Radioembolization with yttrium-90 resin microspheres for neuroendocrine tumor liver metastases

PURPOSE

We aimed to evaluate the effectiveness and safety of radioembolization with yttrium-90 (⁹⁰Y) microspheres in cases with unresectable neuroendocrine tumor liver metastases (NETLMs).

METHODS

Thirty patients (mean age, 55 years) underwent resin-based ⁹⁰Y radioembolization for unresectable NETLM at a single institution between April 2008 and June 2013. Post-treatment tumor response was assessed by cross-sectional imaging using the Response Evaluation Criteria in Solid Tumors (RECIST). Prognostic variables that affected survival were determined.

RESULTS

The mean follow-up was 23.0±19.4 months and the median overall survival was 39 months (95% CI, 12.6–65.4 months), with one- and two-year survival rates of 71% and 45%, respectively. Imaging follow-up using RECIST at three-month intervals demonstrated partial response in 43%, complete remission in 3%, stable disease in 37%, and progressive disease in 17% of patients. Extent of tumor involvement was found to have a statistically significant influence on overall survival (P = 0.03). The existence of extrahepatic disease at the time of radioembolization, radiographic response, age, and primary neuroendocrine tumor site were not significant prognostic factors.

CONCLUSION

The current study demonstrates the effectiveness and safety of radioembolization for the treatment of unresectable NETLMs. We identified that the extent of tumor involvement has a significant effect on overall survival. The use of imaging methods reflecting metabolic activity or cellularity such as scintigraphy or diffusion-weighted MRI would be more appropriate, for the response evaluation of liver metastases after radioembolization.Neuroendocrine tumors (NETs) are a heterogenous group of slow-growing and hormon-releasing malignant tumors. Even though primary NETs originate from a number of locations, 40%–70% of all carcinoids arise in the small intestine and appendix (1, 2). The most common site for metastasis is the liver. Neuroendocrine tumor liver metastasis (NETLM) results in hormone-secretion-related symptoms leading to carcinoid syndrome, pressure on structures, or liver replacement (1–4). Patients with liver metastasis have a five-year survival rate of less than 20% (5). Over the years, improvements in local treatments yielded better control of the symptoms and survival rates, yet only 10% of the patients have limited illness and are eligible for surgery (6). Patient symptomatology and survival can be improved by transarterial treatments like embolization and chemoembolization (6). Limitations of these techniques include the short duration of the effects and the controversial approaches regarding the optimal timing and sequence of the procedures due to the variability of tumor progression (7, 8). Long-term survival benefit was not achieved with systemic chemotherapy (9–11) and treatment with somatostatin analogues is mostly associated with symptomatic relief; there is no clear knowledge of their effect on survival of patients who have carcinoid tumor and metastasis (12).Selective internal radiation therapy (SIRT) has been used to treat unresectable primary and secondary liver cancers for over a decade. Yttrium-90 (⁹⁰Y) is a pure high-energy β emitter with a mean tissue penetration of 2.5 mm. The radioactive microspheres prefer tumoral vascular distribution, so that normal liver tissue is relatively spared and high doses are directed to the tumoral tissue (13). Also, radioembolization-related acute and subacute toxicities are seemingly more tolerable than the ones related to other hepatic embolization procedures (14–16). In this study, we aimed to evaluate the effectiveness and safety of ⁹⁰Y microspheres in cases with unresectable NETLMs.     

Performance of bone tracer for diagnosis and differentiation of transthyretin cardiac amyloidosis: a systematic review and meta-analysis

PURPOSEBone tracers have been validated for many years in detecting transthyretin cardiac amyloidosis (TTR-CA). However, several new studies suggest conflicting results. Our study aimed to systematically evaluate the accuracy of bone radiotracers for diagnosis and differentiation of TTR-CA via a systematic review and meta-analysis.METHODSWe retrieved articles assessing the performance of bone tracer in diagnosing and differentiating TTR-CA from PubMed, the Cochrane Library, ScienceDirect, and DOAJ databases, dating up to 10 July 2020. The meta-analysis was conducted through Stata 16 software, and the risk of bias for the included studies was assessed by the QUADAS-2 tool. Moreover, we made a comprehensive review.RESULTSFourteen articles were included in the systematic review, and 9 in the meta-analysis. The pooled sensitivity was 0.97 (95% confidence interval [95% CI] 0.85–0.99) with heterogeneity (I²=73.5, 95% CI 55.6–91.2), and the specificity was 0.92 (95% CI 0.82–0.96) with heterogeneity (I²=42.0, 95% CI 0.0–86.9). The pooled positive and negative likelihood ratios were 11.49 (95% CI 5.07–26.0) and 0.03 (95% CI 0.01–0.18), respectively. The diagnostic odds ratio was 341 (95% CI 53–2194), and the area under the receiver operating characteristic curve was 0.96 (95% CI 0.94–0.97).CONCLUSIONThe findings evidence that the bone radiotracer is a valuable noninvasive approach that provides high accuracy for diagnosing TTR-CA and plays a modest role in differentiating TTR-CA from immunoglobulin amyloid light-chain cardiac amyloidosis. ^99mTc-HMDP may be more accurate than ^99mTc-PYP, ^99mTc-DPD, and ¹⁸F-NaF in the TTR-CA detecting process, and ¹⁸F-NaF is a promising bone tracer to diagnose and differentiate TTR-CA.

Cardiac amyloidosis (CA) is a group of fatal diseases with poor prognosis (1, 2), which occurs when amyloid (misfolded protein fragments) are deposited in the myocardial extracellular matrix, small blood vessels, and the conduction system (1, 2). The two most frequent types of CA are transthyretin CA (TTR-CA) and immunoglobulin amyloid light-chain CA (AL-CA) (1–5). TTR-CA could be acquired from the aggregation of wildtype TTR (TTRwt), mutant TTR (TTRm), and other types of TTR (3–6). Without typical symptoms, TTR-CA is easily misdiagnosed and underdiagnosed (7, 8), especially in the early stage. From the clinical perspective, doctors often get frustrated in diagnosing TTR-CA and distinguishing TTR-CA from AL-CA, which would delay the optimal treatment and lead to poor prognosis (2).The well-known gold standard for diagnosing TTR-CA depends on endomyocardial biopsy (EMB) (1, 7, 9). Other diagnostic criteria have also been considered (6, 10, 11), such as biopsies from involved organs combined with significant echocardiography findings. Early diagnosis and differentiation of TTR-CA are crucial for the treatment and prognosis (7, 11). Although biopsy combined with additional measures (genotyping or immunohistochemistry) can diagnose and differentiate TTR-CA, biopsy, especially the EMB, cannot be used as a routine procedure due to its possible invasive complications (1–5). Recently, plenty of studies on noninvasive examinations emerged, trying to discuss the early diagnosis of TTR-CA and the differentiation between TTR-CA and AL-CA (10, 12–26). The most representative method is the application of gamma-emitting bone tracers, such as ^99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (^99mTc-DPD), ^99mTc-pyrophosphate (^99mTc-PYP), and ^99mTc-hydroxymethylene diphosphonate (^99mTc-HMDP) (12–24). Besides, the positron emission tomography (PET) bone tracer ¹⁸F-sodium fluoride (¹⁸F-NaF) has also been used to explore the diagnosis and differentiation of TTR-CA (25, 26).Most studies suggest that bone tracers can diagnose and differentiate TTR-CA. A prior meta-analysis has partly reported the diagnostic accuracy of gamma-emitting bone tracers in TTR-CA (27). Nevertheless, the differentiation of TTR-CA from AL-CA was not fully elaborated, and it did not provide a systematic review and include the positron-emitting bone tracer ¹⁸F-NaF. More importantly, several new studies have indicated that bone radiotracers present suboptimal sensitivity in detecting some TTR-CA (28, 29), which contradicts previous analyses. Therefore, we sought to provide further evidence on the role of bone tracers in TTR-CA diagnosis and CA subtype differentiation by performing a more comprehensive systematic review and a meta-analysis.     

Role of magnetic resonance spectroscopy in differential diagnosis of solitary pulmonary lesions

PURPOSEThe aim of our study was to evaluate the availability of magnetic resonance spectroscopy (MRS) for the differentiation of benign or malignant pulmonary nodules and masses.METHODSA total of 59 patients (45 male, 14 female) with pulmonary nodules and masses were included in this prospective study. MRS was applied to the pulmonary lesions of the patients and choline levels were determined. Afterwards CT-guided percutaneous needle biopsy was performed. According to the biopsy results, pulmonary lesions were benign in 25 patients and malignant in 34 patients.RESULTSCholine levels were significantly higher in malignant lesions compared with benign lesions (p < 0.001). When the other conditions were kept constant, the probability of malignancy significantly increased by 17.38-fold (95% CI, 3.78–79.93) in those with choline levels >1.65 μmol/g compared to those with choline levels ≤1.65 μmol/g (p < 0.001).CONCLUSIONMRS is a noninvasive method that can be used in the differential diagnosis of pulmonary nodules and masses.

The majority of the solitary pulmonary nodules have a benign character (1). However, all pulmonary nodules should be considered as malignant lesions unless proven otherwise (2). The differential diagnosis of these lesions may be an important problem in routine medical practice. Computed tomography (CT) is the standard method for the examination of the nodules and mass lesions (3). CT imaging of morphological features like size, margins, and calcification enables the investigation of malignancy (4). However, there is some overlap so that some malignant lesions may appear benign, while some benign nodules may show morphological features typical for malignancy (5). CT imaging for differantial diagnosis have problems like false-negative and false-positive results, over-diagnosis, benign nodule resections, and exposure to radiation (6). Biopsy is the most reliable and effective method for the diagnosis of the pulmonary nodules and mass lesions. However, it may cause serious complications such as pneumothorax, hemoptysis, air embolism, tumor cell seeding and death (7, 8). In addition, the tolerability of this invasive intervention is rather low among patients.Magnetic resonance imaging (MRI) provides information about the tumor morphology and magnetic resonance spectroscopy (MRS) provides biochemical information about the physiology and metabolism of the disease (9). MRS enables molecular analysis of the tissues based on the display of different chemical shifts of certain nuclei in the magnetic field (10). MRS was initially used in neuroradiology for characterization of tumor, stroke, epilepsy, infection, and neurodegenerative diseases. In recent years, it was also introduced in the evaluation of lesions in other organs like breast (11), liver (12), pancreas (13), and prostate (14). There are some in vitro studies in the literature on the use of MRS in lung cancer showing higher lactate and total choline peaks compared with normal tissues (15, 16). Also there is one case report in the literature regarding the feasibility of using MRS in lung cancer (17).The objective of this study was to demonstrate the value of MRS, which is a noninvasive method and does not require a contrast agent, in the differential diagnosis of pulmonary nodules and mass lesions.     

Diagnostic performance of radiomics using machine learning algorithms to predict MGMT promoter methylation status in glioma patients: a meta-analysis

PURPOSEWe aimed to assess the diagnostic performance of radiomics using machine learning algorithms to predict the methylation status of the O⁶-methylguanine-DNA methyltransferase (MGMT) promoter in glioma patients.METHODSA comprehensive literature search of PubMed, EMBASE, and Web of Science until 27 July 2021 was performed to identify eligible studies. Stata SE 15.0 and Meta-Disc 1.4 were used for data analysis.RESULTSA total of 15 studies with 1663 patients were included: 5 studies with training and validation cohorts and 10 with only training cohorts. The pooled sensitivity and specificity of machine learning for predicting MGMT promoter methylation in gliomas were 85% (95% CI 79%–90%) and 84% (95% CI 78%–88%) in the training cohort (n=15) and 84% (95% CI 70%–92%) and 78% (95% CI 63%–88%) in the validation cohort (n=5). The AUC was 0.91 (95% CI 0.88–0.93) in the training cohort and 0.88 (95% CI 0.85–0.91) in the validation cohort. The meta-regression demonstrated that magnetic resonance imaging sequences were related to heterogeneity. The sensitivity analysis showed that heterogeneity was reduced by excluding one study with the lowest diagnostic performance.CONCLUSIONThis meta-analysis demonstrated that machine learning is a promising, reliable and repeatable candidate method for predicting MGMT promoter methylation status in glioma and showed a higher performance than non-machine learning methods.

Glioma is the most common type of primary malignant central nervous system (CNS) tumor and accounts for approximately 75% of primary malignant CNS tumors (1). Despite developments in surgery, chemotherapy, and radiotherapy, patients with glioma still suffer an unpleasant prognosis (2). In recent years, increasing attention has been given to molecular markers in patients with glioma. O⁶-methylguanine-DNA methyltransferase (MGMT) is a key gene that encodes a DNA repair enzyme. The methylated MGMT promoter is usually related to better overall survival in temozolomide (TMZ)-treated gliomas (3–5). In addition, the MGMT gene is a potential attractive therapeutic target in the molecularly targeted therapy field (6, 7). Moreover, it has been reported that MGMT promoter methylation status is significantly associated with glioma pseudo-progression in recent studies (8, 9).At present, the approaches for determining MGMT promoter methylation status in glioma are based on surgical sampling (10), which is an invasive procedure and may induce severe complications. The results always take a relatively long period, which may delay important therapeutic decisions and be influenced by intra-tumoral heterogeneity. Thus, identifying a noninvasive, preoperative, and robust means to detect MGMT promoter status is of great significance. Radiomics, which is an advanced imaging analysis technique, utilizes algorithms to automatically extract a large number of data features to convert imaging data into a high-dimensional and mineable feature space (11). Machine learning algorithms have been used to create credible statistical models for classification in radiomics (12), and they have already had a powerful influence on radiology practice and could further change the area of radiology (13–15). For the CNS, magnetic resonance imaging (MRI) is the most common and noninvasive preoperative diagnostic imaging method. Increasing evidence in neuro-oncology has indicated that radiomics features based on MRI can predict the molecular subtype of glioma (16–18).In recent years, a few studies have demonstrated that machine learning performs well in predicting MGMT promoter methylation status in glioma (16, 18–22). However, to our knowledge, no study has performed a systematic assessment of the diagnostic accuracy of machine learning for predicting MGMT promoter methylation status. Thus, our meta-analysis aimed to systematically evaluate the diagnostic efficacy of machine learning for predicting MGMT promoter methylation status in patients with glioma.     

Monitoring the therapeutic efficacy of CA4P in the rabbit VX2 liver tumor using dynamic contrast-enhanced MRI

PURPOSEThe present work aims to evaluate whether dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can monitor the blocking effect of combretastatin-A4-phosphate (CA4P) on microvessels and assess the therapeutic efficacy.METHODSForty rabbits were implanted VX2 tumor specimens. Two weeks later, serial MRI (T1-weighted imaging, T2-weighted imaging, and DCE) were performed at 0 h, 4 h, 24 h, 3 days, and 7 days after CA4P (10 mg/kg) or saline treatment. The parameters of DCE (K^trans, K_ep, V_e and iAUC60) enhancement of tumor portions were measured. Then all tumor samples were stained to count microvessel density (MVD). Finally, two-way repeated measures ANOVA was used to analyze the difference between and within groups. Correlation between the DCE parameters and MVD was analyzed by using the Pearson correlation and Spearman rank correlation.RESULTSK^trans and iAUC60 values at 4 h after CA4P treatment were significantly lower than those in the control group (D-value: −0.133 min⁻¹, 95%CI: −0.169 to −0.097 min⁻¹, F= 59.109, p < 0.001 for K^trans; D-value: −10.533 mmol/s, 95%CI: −17.147 to −3.919 mmol/s, F= 11.110, and p = 0.003 for iAUC60). In the CA4P group, K^trans and iAUC60 reached the minimum values at 4 h, and both parameters showed significant difference between 4 h and other time points (all p < 0.01). Seven-day values of K^trans (r=0.532, p = 0.016 and r=0.681, p = 0.001, respectively) and iAUC60 (r=0.580, p = 0.007 and r=0.568, p = 0.009, respectively) showed correlation with MVD in both groups, while K_ep and V_e did not show correlation with MVD (p > 0.05).CONCLUSIONThe blocking effect of microvessels after CA4P treatment can be evaluated by DCE-MRI, and the parameters of quantitative K^trans and semi-quantitative iAUC60 can assess the change in tumor angiogenesis noninvasively.

Hepatocellular carcinoma (HCC) has the third highest mortality rate worldwide among cancers (1). Although the 5-year survival rate can reach up to 70% of HCC patients by surgical operation, only less than 30% are suitable for surgery. Transarterial chemoembolization (TACE) treated tumors can stimulate angiogenesis and require repeated treatment (2). As HCC is generally hypervascular, vascular targeting strategies can be used to improve the 5-year survival rate (3).There are two kinds of tumor vascular targeted agents (4): angiogenesis inhibitors (AIs) and vascular disrupting agents (VDAs). AIs can prevent the formation of new blood vessels by inhibiting angiogenesis. VDAs can damage the tumor endothelium directly, shutdown vascular development rapidly and selectively and cause tumor cell ischemia; tumor vascular shutdown occurs within 1 h of administration, and lasts for 24 hours (5, 6). Combretastatin A-4-phosphate (CA4P) is a new-style VDA that progressed into clinical trial stage (7–9).The vascular disrupting effects of VDAs can be assessed by microvessel density (MVD), which is the “gold standard” measurement to evaluate angiogenesis. However, the invasiveness of MVD measurement limits its use (10).During the development of targeted treatments, imaging plays an important role in monitoring the treatment efficacy against malignant tumors (11). Although change in tumor size may not be a reliable method to measure treatment efficacy, plenty of imaging sequences have been developed to overcome the drawbacks of traditional efficacy assessments by size measurement (12–14).DCE-MRI could reflect the microvascular structure and function indirectly, noninvasively and quantitatively, and it has been widely applied to predict and evaluate the treatment response (15). DCE-MRI is expected to be useful in evaluating early vascular disrupting efficacy after CA4P administration. But studies focusing on the changes of DCE parameters at different time points after CA4P administration in the VX2 rabbits have been scarce (16–18). The VX2 liver tumor is supplied by liver artery which is similar with high-grade human HCC, and can be used to simulate the microenvironment of human HCC (19).In this study, we aimed to investigate whether quantitative parameters in DCE-MRI can monitor the change in microvasculature of liver tumors at different time points after CA4P treatment.     

Scheduling surgery after transarterial embolization: does timing make any difference to intraoperative blood loss for renal cell carcinoma bone metastases?

PURPOSEOur purpose is to clarify the optimal timing of surgery after transarterial embolization (TAE) for renal cell carcinoma (RCC) bone metastases.METHODSThis retrospective study included 41 patients with RCC bone metastases embolized between 2013 and 2019. Different-sized particulate and/or liquid embolic agents were used for TAE. Embolizations were categorized into groups 1–3 according to the interval between TAE and surgery (group 1: <1 day, group 2: 1–3 days, group 3: >3 days). Degree of embolization after TAE was graded visually based on angiographic images (<50%, 50%–75%, 75%–90%, >90%). The relationship between the TAE–surgery interval and intraoperative blood loss (IBL) and the correlation between IBL and embolization grade were examined. Lesion sizes and the relationships among lesion localizations and contrast media usage, intervention time, and IBL were also analyzed.RESULTSForty-six pre-operative TAEs (single lesion at each session) were performed in this study (26 in group 1, 13 in group 2, 7 in group 3). Lesion sizes and distributions were similar between groups (p = 0.897); >75% devascularization was achieved in 40 (TAEs 86.96%), but the IBL showed no correlation with the embolization rate (r=0.032, p = 0.831). The TAE–surgery interval was 1–7 days. The median IBL in group 1 (750 mL; range, 150–3000 mL) was significantly lower than those in the other groups (p = 0.002). Contrast media usage (p = 0.482) and intervention times (p = 0.261) were similar for metastases at different localizations. IBL values after TAE were lower for extremity metastases (p = 0.003).CONCLUSIONBone metastases of RCC are well-vascularized, and to achieve lowest IBL values, surgery should preferably be performed <1 day after TAE.

Renal cell carcinomas (RCCs) are one of the leading causes of cancer-related death worldwide (1). About one-third of RCCs are metastatic at initial diagnosis, and skeletal metastases are the second most frequent type of RCC metastases following lung metastases (43%) (2, 3). Surgical intervention is an option for the treatment of skeletal metastases of RCCs. Although local ablative therapies like thermal ablation may be preferred for tumors <3 cm, systemic chemotherapy and radiotherapy are other options for suitable patients (4). However, RCCs are usually chemo/radio-resistant (50%), and these treatment options are usually favored for palliative intent (3–5).The 5-year overall survival of patients with RCC bone metastases increases when surgical metastasectomy is performed (4). However, since RCC metastases in the skeletal system are usually hypervascular, the operative blood loss could be as high as 18500 mL, which could threaten patients’ lives (6). Transarterial embolization (TAE) of bone tumors was first described in 1975 (7). The operative blood loss can be reduced by adequate devascularization after TAE of the bone metastases (8–11), and a blood loss of less than 3000 mL was defined as clinical success for spinal tumor surgeries (12). Selective TAE of bone metastases can be performed pre-operatively in a single session. Successful embolization can clarify the tumor margins from the surrounding tissue planes, simplifying surgical manipulation of the tumors. Thus, recurrence rates may be lower in patients undergoing this treatment combination (13, 14). Different types of permanent and temporary embolic agents can be selected for TAE of bone metastases. The rationale behind TAE is occlusion of the capillary bed of the tumors; therefore, proximal occlusion should not be preferred due to the presence of numerous collateral capillary vessels (5, 8, 15).This study aimed to clarify the optimal interval between TAE and surgery for RCC bone metastasis to minimize blood loss at the time of surgery.     

Are the washout values currently accepted for lesion characterization in dedicated adrenal CT adequate for diagnosis?

PURPOSEWe aimed to investigate the accuracy of density characteristics and washout values of lesions detected on computed tomography (CT) at the cutoff values obtained from the literature by taking the pathological results of adrenalectomy specimens as reference and to determine the cutoff values of parameters evaluated on CT for the differentiation of adenoma and nonadenoma lesions in the study group.METHODSHospital records and standard CT imaging data (noncontrast early phase [65 s] and late phase [15 min] ) of 84 patients with 87 lesions who underwent adrenalectomy between January 2012 and December 2018 were retrospectively reevaluated by two radiologists in consensus. The patients were categorized as having adenoma and nonadenoma lesions according to the pathology results. The sensitivity, specificity and diagnostic accuracy of CT parameters (density values and washout percentages) were evaluated. Differences in the CT parameters (size, noncontrast and early-late enhancement density and absolute and relative washout values) were investigated. The optimal cutoff values of CT parameters were determined by ROC analysis.RESULTSNoncontrast CT had a specificity of 87.75% and 95.9%, sensitivity of 60% and 48.6%, diagnostic accuracy of 77.7% and 89.47% for adenomas, at the cutoff values of ≤10 HU and ≤0 HU, respectively. For absolute washout value ≥ 60%, the sensitivity, specificity and accuracy were 64.7%, 52.38% and 56.75%, respectively; while these rates were 76.47%, 56.52% and 62.16%, respectively, for relative washout value ≥40%. Adenomas and nonadenomas showed significant difference in terms of size (p < 0.0001), unenhanced attenuation (p < 0.0001), relative washout (p = 0.020) and delay enhancement (p < 0.001). But there were no differences in terms of absolute washout (p = 0.230) and early enhancement (p = 0.264). The cutoff values for the differentiation of adenomas and nonadenomas were as follows: size ≤44 mm, noncontrast density <20 HU, early-phase density ≥45 HU, delayed-phase density ≤44 HU, absolute washout 74.83% and relative washout 57.76%.CONCLUSIONThe current washout criteria used in the differentiation of adenoma and nonadenoma lesions in dynamic CT imaging can give false negative and positive results. According to the existing criteria, the most reliable parameter in adenoma–nonadenoma differentiation is ≤ 0 HU noncontrast CT density value.

According to the autopsy studies, adrenal masses are among the most common tumors detected in humans (1). In autopsy series, this prevalence has been reported as 1% to 9.8% (1). With the advances in imaging techniques and their increasing use, there has also been a recent increase in radiologically reported adrenal masses (2–5), varying between 0.35% and 5% for CT examinations (6). Adenomas are the most common adrenal lesions in patients without primary malignancy (1, 7, 8). Although adrenal gland is a common site for distant metastases in patients with known malignancies, adenomas are more common than metastases in these patients. Since the majority of adrenal adenomas are benign and nonfunctional lesions, a clinical and radiological follow-up is sufficient. In nonadenoma lesions, a biopsy or direct surgical resection can be recommended according to the characteristics of the patient. Therefore, determination of whether a detected adrenal mass is an adenoma or nonadenoma is critically important in patient management and changes the form of treatment (9).Computed tomography (CT) is the radiological method of choice in the characterization of adrenal mass lesions (8, 10). Adenomas have low density values in noncontrast CT scans due to their intracytoplasmic fat content (3, 6, 10, 11). However, as much as 30% of adrenal adenomas are poor in fat, thus making it impossible to distinguish them from other masses based on noncontrast CT density (8, 10). In this case, most authors reported that the washout character determined by dynamic contrast-enhanced CT examination differentiates adrenal adenomas from other lesions (10–13). Due to their rich capillary network, adenomas are stained early with the contrast agent, causing them to exhibit a high level of washout (8). However, some nonadenoma lesions, particularly pheochromocytoma, have been reported to show a similar washout pattern (4, 14–18). In the literature, there are many studies that investigated noncontrast and contrast-enhanced CT density and the washout criterion for the differentiation of adenoma and nonadenoma lesions (4, 6, 10–18). However, the scan parameters used in these studies, the characteristics of the devices, the time of wash-in and washout, contrast agent dose, and iodine concentration are not standard and show differences (e.g., 2.5–10 mm collimation; 3–5 mm reconstruction intervals; 80–140 kVp; 150–370 mA; 0.75–3:1 pitch; nonhelical, helical, or multi-slice device; 35–120 s wash-in time; 3–45 min washout time; 100–150 mL contrast agent dose; 300–370 mg/L iodine concentration). In a study using different minutes as washout criteria in the same lesions, different specificity and sensitivity values were found according to the washout time (19). In studies evaluating the effectiveness of adrenal CT in the literature, the reference method also differs. For these reasons, the available literature data is far from being standard. Nonadenoma lesions, which are evaluated as adenoma based on the available data, may cause serious problems in patient management.In the current study, we aimed to investigate the accuracy of density characteristics and washout values of lesions detected on CT at the cutoff values obtained from the literature by taking the pathological results of adrenalectomy specimens as reference to determine the cutoff values of parameters evaluated on CT for the differentiation of adenoma and nonadenoma lesions in the study group.     

Guidewire-catheter induced hydrodissection to assist radiofrequency ablation for subcapsular hepatocellular carcinoma with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion

PURPOSEWe aimed to evaluate the usefulness of guidewire-catheter induced hydrodissection (GIH) to assist radiofrequency ablation (RFA) for subcapsular hepatocellular carcinoma (HCC) with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion.METHODSThis retrospective study included 17 patients with small subcapsular HCC ineligible for ultrasonography-guided RFA who received RFA under guidance of fluoroscopy and cone-beam computed tomography immediately after iodized oil transarterial chemoembolization (TACE) between April 2011 and January 2016. In the study patients, creation of artificial ascites to protect the perihepatic structures failed due to perihepatic adhesion and GIH was attempted to separate the perihepatic structures from the ablation zone. The technical success rate of GIH, technique efficacy of RFA with GIH, local tumor progression (LTP), peritoneal seeding, and complications were evaluated.RESULTSThe technical success rate of GIH was 88.24% (15 of 17 patients). Technique efficacy was achieved in all 15 patients receiving RFA with GIH. During an average follow-up period of 48.1 months, LTP developed in three patients. Cumulative LTP rates at 1, 2, 3, and 5 years were 13.3%, 20.6%, 20.6%, and 20.6%, respectively. No patient had peritoneal seeding. Two of the 15 patients receiving RFA with GIH had a CIRSE grade 3 liver abscess, but none had complications associated with thermal injury to the diaphragm or abdominal wall near the ablation zone.CONCLUSIONGIH can be a useful method to assist RFA for subcapsular HCC with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion.

Radiofrequency ablation (RFA) is widely accepted as a curative treatment for patients with small (≤3 cm) hepatocellular carcinoma (HCC) not suitable for surgery (1, 2). However, when the tumor is located close to the liver surface, RFA carries a risk of unintended collateral thermal injury to the perihepatic structures (i.e., diaphragm and abdominal wall). To overcome this problem, adjunctive techniques such as introduction of artificial ascites or pleural effusion have been applied (3–8). Nonetheless, patients with perihepatic peritoneal adhesion may still be at risk of collateral thermal injury as adhesion prevents separation of the perihepatic structures by artificial ascites from the ablation zone (6, 9, 10). Some investigators have used an alternative technique making localized hydrodissection by using an 18–22 G needle at the contact point between the index tumor and perihepatic structure (9, 11). However, this also seems to be not applicable when the lung or bowel interposes on the access route.Prior iodized oil transarterial chemoembolization (TACE) enhances the feasibility of subsequent RFA for small tumors with poor conspicuity (12, 13). This is because intratumoral retention of radio-opaque iodized oil provides radiographic contrast to the index tumor. As the index tumor with iodized oil retention is clearly seen on fluoroscopy and the perihepatic peritoneal space is easily accessed by traditional methods of making artificial ascites (6, 9, 14), an angiographic catheter and guidewire system can reach the region near the tumor through the perihepatic space under fluoroscopic guidance. Therefore, in patients with perihepatic adhesion, if forceful advancement of the catheter and guidewire system could dissect the adhesion, introduction of fluid via the catheter tip at the region near the tumor may protect the perihepatic structures from thermal injury during RFA for subcapsular HCC.The aim of this study was to evaluate the usefulness of guidewire-catheter induced hydrodissection (GIH) to assist RFA for subcapsular HCC with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion.     

The position of transarterial chemoembolization with drug-eluting beads and yttrium-90 transarterial radioembolization in patients with hepatocellular carcinoma: Consensus statements from a Delphi-method expert panel in Turkey

PURPOSEClinical studies conducted in different geographic regions using different methods to compare transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) have demonstrated discordant results. Meta-analyses in this field indicate comparable overall survival (OS) with TACE and TARE, while reporting a longer time to progression and a higher downstaging effect with TARE treatment. In terms of isolated procedure costs, treatment with TARE is 2 to 3 times more, and in some countries even more, expensive than TACE. However, relevant literature indicates that TARE is more advantageous compared to TACE regarding the need for repeat procedures, costs of complication management, total hospital stay and quality of life. Heterogeneity of hepatocellular carcinoma (HCC) patients as well as the shortcomings of clinical classifications, randomized clinical trials and cost-effectiveness studies make it difficult to choose between treatment alternatives in this field. As in other countries, these challenges lead to differences in treatment choice across different centers in Turkey.METHODSThe present expert panel used two round modified Delphi method to investigate the resources and clinical parameters referenced while selecting patients for drug-eluting beads (DEB)-TACE and TARE treatment modalities in Turkish clinical practice. The cost-effectiveness parameters and comparisons of these treatments have also been evaluated at a prediction level.RESULTSThe panelists stated that they most commonly use the BCLC staging system for the management of HCC patients in Turkey. However, they did not find any of the staging systems or treatment guidelines sufficient enough for their clinical practice in terms of covering the down-staging intent of treatments. Since living donor transplant preference is higher in Turkey than the rest of the Western countries, down-staging treatments are thought to be more prioritized in Turkey than that in other Western countries. The panelists reached a consensus that TARE may provide improved OS and reduce the number of repeat procedures compared to DEB-TACE in intermediate-stage patients with a single tumor spanning a diameter above 5 cm who experience recurrence after previous treatment with TACE and most TACE-naïve patient groups in intermediate stage.CONCLUSIONBased on the consensus on OS and the number of procedures, the panelists assumed that TARE would be more cost-effective than DEB-TACE in most groups of TACE-naïve patients in intermediate stage and in those with a single tumor spanning a diameter above 5 cm. It was also stated that the predicted cost-effectiveness advantage of TARE could be more pronounced in patients with a tumor diameter greater than 7 cm.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death (1). Unlike other cancers, disease course and treatment vary based on the underlying liver disease and remaining liver reservoir in addition to tumor burden (2). Based on the treatment guidelines in this field, cases in the early stage are candidates for curative treatment options such as ablation, resection, and transplantation (2–4). Available clinical data show that only a limited number of cases are diagnosed at early stage and HCC cases encountered in daily clinical practice are often in more advanced stages of the disease (1, 5).According to the Barcelona Clinic Liver Cancer (BCLC) staging system, which is commonly referenced in this field, and treatment guidelines that adopt this system, transarterial chemoembolization (TACE) is the standard of care for patients with intermediate HCC (BCLC-B) (2, 6–11). Currently, the transarterial chemoembolization with drug-eluting beads (DEB-TACE) method is a novel TACE modality and a candidate to replace the lipiodol-TACE (conventional TACE) approach, which has been in use for a long time (12). Although transarterial radioembolization (TARE; selective internal yttrium-90 radiotherapy or SIRT) is not included in the BCLC staging system, it appears to be an alternative treatment method with increasing indications in parallel with the advances in angiography techniques and dosimetry at every stage included in BCLC guidelines (13).Clinical studies conducted in different geographic regions using different methods to compare TACE and TARE have demonstrated discordant results. Meta-analyses in this field indicate comparable overall survival (OS) with TACE and TARE, while reporting a longer time to progression (TTP) and a higher downstaging effect with TARE treatment (14–21).In terms of isolated procedure costs, treatment with TARE is 2 to 3 times more, and in some countries even more, expensive than TACE (22, 23). However, relevant literature indicate that TARE is more advantageous compared to TACE with regard to need for repeat procedures, costs of complication management, total hospital stay, and quality of life (24). Globally, there is only a limited number of studies investigating the effects of TACE and TARE on national health budgets and comparing the cost-effectiveness of these methods (23, 25).Heterogeneity of HCC patients as well as the shortcomings of clinical classifications, randomized clinical trials and cost-effectiveness studies make it difficult to choose between treatment alternatives in this field (2). As in other countries, these challenges lead to differences in treatment choice across different centers in Turkey.The present expert panel used the modified Delphi method to investigate the resources and clinical parameters referenced while selecting patients for DEB-TACE and TARE treatment modalities in Turkish clinical practice. The cost-effectiveness parameters and comparisons of these treatments have also been evaluated at a prediction level.     

Palliative local treatment of bone metastases by 125I seed brachytherapy under DynaCT guidance: single-center experience

PURPOSEWe aimed to evaluate the clinical benefit of ¹²⁵I seed brachytherapy under DynaCT guidance for palliative local treatment of bone metastases.METHODSFrom December 2014 to September 2017, 82 patients with painful bone metastases, who experienced treatment failure using standard strategies or rejected treatment were enrolled in this retrospective study. All patients underwent ¹²⁵I seed brachytherapy under DynaCT guidance. Technical success, visual analogue scale (VAS), numerical rating scale (NRS), verbal rating scale (VRS), Karnofsky performance status (KPS) and complications were analyzed.RESULTSThe success rate of ¹²⁵I seed implantation was 100%. The VAS and NRS scores for the most severe pain were 7.0 (5.0–9.0) and 8.0 (6.0–9.0) before brachytherapy. The pain scores assessed every 2 hours gradually decreased within 12 hours (p < 0.001). A comparison of KPS scores showed that patients had significantly better quality of life on weeks 1, 4, and 8 than on week 0 (p < 0.001). The associated complications were mild subcutaneous hemorrhage 25.6% (21/82), fever 7.3% (6/82), minor displacement of radioactive seeds 5.0% (4/82), pathologic fracture 2.4% (2/82), and local skin reaction 2.4% (2/82). After symptomatic treatment, all complications were relieved. Minor displacement of radioactive seeds did not cause damage to adjacent tissues. No serious life-threatening complications occurred in the study group.CONCLUSIONDynaCT-guided ¹²⁵I seed implantation is a safe and effective method for palliation of painful bone metastases from cancer after failure or rejection of conventional treatments.

Bone metastasis is a common problem in patients with advanced cancer, which is detrimental to their quality of life (1, 2). The incidence of bone metastasis and metastatic sites varies significantly depending on the primary tumor (3). It is estimated that about 50% or more cancer patients will have bone metastasis (4, 5). In fact, patients with bone metastases still suffer from poorly controlled pain during the treatment or progression of the disease, which can seriously affect diet, sleep, emotion, and daily activities (6). Therefore, the most important task of advanced cancer treatment is not only to improve survival rate, but also to relieve pain and improve the quality of life.Palliative radiation therapy combined with analgesia is the standard treatment of painful bone metastasis (7, 8). Although external beam radiotherapy (EBRT) is an important method to relieve bone pain, it remains ineffective in 30% of patients, while nearly 50% of patients have recurrent pain after EBRT (9–11). Furthermore, due to previous EBRT treatment, patients with bone metastases (particularly spine metastases) may have reached the value of dose tolerance, limiting their treatment options. As an alternative to EBRT, percutaneous iodine-125 (¹²⁵I) seed brachytherapy may resolve this issue by providing a high dose of radiation straight to the tumor target, while reducing the effects on adjacent normal tissues (12). This study focused on the safety and efficacy of DynaCT-guided ¹²⁵I seed brachytherapy for bone metastases at different sites.     

Malpositioned endoscopically inserted biliary stent causing massive hematemesis managed with vascular plug and stenting

A 46-year-old man with a history of hepatitis B cirrhosis and hepatocellular carcinoma (HCC) status post liver transplantation two years ago complicated by HCC recurrence and biliary stenosis presented with hypovolemic shock and melena one month after endoscopic exchange of plastic biliary stents. During endoscopic retrograde cholangiopancreatography, patient was found to have hemobilia and developed uncontrollable bleeding after a common bile duct (CBD) sweep managed by insertion of a stent-graft across major papilla into presumed CBD. The bleeding continued with subsequent negative angiography, and a computed tomography angiography showed malpositioned stent-graft between major papilla and inferior vena cava (IVC). This was successfully managed by the deployment of a vascular plug inside the stent graft and excluding it by deploying a stent across the affected area in IVC.

Endoscopic retrograde cholangiopancreatography (ERCP) is the most common procedure used to diagnose and treat primary pancreaticobiliary disorders and manage postoperative complications. Overall, ERCP has a high technical success and is considered a safe procedure (1). Although with increasing operator experience and advances in technology the safety profile of ERCP is improving, it still could potentially result in severe complications (2). In liver transplant recipients, biliary complications such as biliary stenosis and Oddi sphincter dysfunction are common and can happen in 5%–20% of the patients (3, 4). With the refinement of orthotopic liver transplantation surgical technique, especially donor to recipient biliary duct-to-duct anastomosis and preserving the gastrointestinal anatomy, ERCP plays a central role for the minimally invasive management of biliary complications (5). ERCP outcomes and complications in the general population is very well understood; however, the evidence regarding post-ERCP complications in liver transplant recipients is poor, and few more recent studies suggest an overall complication rate of 9%–15% (5, 6), including a bleeding risk of 2%–3.8% (5, 6) and perforation risk of 0.6% (6), which is higher than what is reported in the general population (7).Interventional radiology (IR) procedures such as percutaneous transhepatic cholangiography and drainage are the second line in managing biliary complications of liver transplant recipients. However, IR still plays a vital role in managing procedural complications, such as bleedings that are challenging to control. We are reporting a rare severe ERCP complication in a liver transplant recipient resulting in uncontrolled bleeding. The bleeding was due to perforation between the common bile duct and inferior vena cava (IVC) and inadvertent deployment of a stent-graft connecting the IVC and duodenum. The complication resulted in massive hematemesis and pulmonary emboli and was successfully managed by an unusual IR approach.     

Diagnostic performance rates of the ACR-TIRADS and EU-TIRADS based on histopathological evidence

PURPOSEIn this study, we aimed to assess the effectiveness of malignancy stratification algorithms of the American College of Radiology (ACR) and European Thyroid Association (ETA) in the delineation of thyroid nodules using a database of nodules that were unequivocally diagnosed by means of histopathological examination and meticulously matched with the imaged nodules.METHODSA total of 165 patients having 251 thyroid nodules with histopathologically proven definitive diagnoses during a 5-year period were included in this study. All patients had preoperatively undergone ultrasonography (US) examination, and US characteristics of the thyroid nodules were retrospectively analyzed and assigned in compliance with the thyroid imaging reporting and data system categories recommended by the ACR (ACR-TIRADS) and ETA (EU-TIRADS). The diagnostic effectiveness in the delineation of thyroid nodules and unnecessary fine-needle aspiration (FNAB) rates were evaluated.RESULTSOverall, 189 nodules (75.30%) were diagnosed as benign, while 62 nodules (24.70%) were reported to be malignant based on histopathological assessment. Sensitivity and specificity rates were 71% and 75% for ACR-TIRADS and 73% and 80% for EU-TIRADS. The area under the curve values were 0.78 and 0.80 for ACR-TIRADS and EU-TIRADS, respectively. The unnecessary FNAB rates were 61% for ACR-TIRADS and 64% for EU-TIRADS as per the recommended criteria of each algorithm.CONCLUSIONThe diagnostic performance of both malignancy stratification systems was signified to be moderate and sufficient in a cohort of nodules with definite histopathological diagnosis. In light of our results, we demonstrated the strengths and weaknesses of the ACR- and EU-TIRADS for physicians who should be familiar with them for optimal management of thyroid nodules.

The number of detected thyroid nodules has been increasing in recent years with the widespread application of ultrasonography (US). The reported incidence varies from 20% to 68% in patients undergoing high-frequency US examination (1, 2). In case of a newly detected nodule, the primary concern is to discriminate benign ones, which constitute almost 90%, from malignant ones that require additional invasive procedures (3, 4). Fine-needle aspiration biopsy (FNAB) is the primary diagnostic tool due to its high sensitivity and specificity in distinguishing malignancy, yet it has several shortcomings, including inconclusive results and potential overdiagnosis (5).The particular nodular US features suggestive of malignancy are well known and thus US is employed for the indication of FNAB (6, 7). Nevertheless, none of those characteristics individually predicts the malignancy risk sufficiently (8, 9). Hence, various risk-stratification systems that consider a set of nodular US features have been established to predict the malignancy risk, mitigate superfluous FNABs, and enhance interobserver concordance. Among them, the Thyroid Imaging Reporting and Data System of the American College of Radiology (ACR-TIRADS) was set up in 2017 to classify all detected thyroid nodules according to its issued lexicon (10–12). Similarly, the European Thyroid Association TIRADS (EU-TIRADS) was developed to improve the sensitivity together with high negative predictive value (NPV) in characterization with a more straightforward scoring method (12, 13). Several studies have compared the effectiveness of these two risk-stratification systems (14–18), yet their performance in different thyroid nodules with various histopathologic results and subtypes still needs to be investigated.The objectives of our study were to appraise the diagnostic effectiveness of the ACR- and EU-TIRADS classification systems in nodular characterization and to analyze the rates of inappropriate FNABs according to the proposed criteria based on unequivocal histopathological results.     

Radiomics signature for predicting postoperative disease-free survival of patients with gastric cancer: development and validation of a predictive nomogram

PURPOSE Radiomics can be used to determine the prognosis of gastric cancer (GC). The objective of this study was to predict the disease-free survival (DFS) after GC surgery based on computed tomography-enhanced images combined with clinical features.METHODS Clinical, imaging, and pathological data of patients who underwent gastric adenocarcinoma resection from June 2015 to May 2019 were retrospectively analyzed. The primary outcome was DFS. Radiomics features were selected using Least Absolute Shrinkage and Selection Operator algorithm and converted into the Rad-score. A nomogram was constructed based on the Rad-score and other clinical factors. The Rad-score and nomogram were validated in the training and validation groups.Results Totally, 179 patients were randomly divided into the training (n = 124) and validation (n = 55) groups. In the training group, validation group, and overall population, the Rad-score could be divided into categories indicating low, moderate, and high risk of recurrence, metastasis, or death; all risk categories showed a significant difference between the training, validation, and overall population groups (all P < .001). Positive lymph nodes (hazard ratio (HR) = 3.07, 95% CI: 1.52-6.23, P = .002), cancer antigen-125 (HR = 3.24, 95% CI: 1.54-6.80, P = .002), and the Rad-score (HR = 0.73, 95% CI: 0.61-0.87, P < .001) were independently associated with DFS. These 3 variables were used to construct a nomogram. In the training group, the areas under the curve at 3 years were 0.758 and 0.776 for the Rad-score and the nomogram, respectively, while they were both 1.000 in the validation group. The net benefit rate was analyzed using a decision curve in the training and validation groups, and the nomogram was superior to the single Rad-score.CONCLUSION Rad-score is an independent factor for DFS after gastrectomy for GC. The nomogram established in this study could be an effective tool for the clinical prediction of DFS after gastrectomy.

Main points

• Rad-score is an independent factor for disease-free survival (DFS) after gastrectomy for gastric cancer.
• Rad-score could be divided into categories indicating low, moderate, and high risk, and each category was associated with distinct DFS.
• Nomogram could be an effective tool for the clinical prediction of DFS after gastrectomy.

Gastric adenocarcinomas are the most common type of stomach cancer.^1,2 There are 1 033 701 new gastric cancer (GC) cases and 872 685 GC-related deaths worldwide in 2018.³ Some regions including Eastern Asia, Eastern Europe, and South America have the highest incidence of GC.^2,4 The treatment management of GC includes surgery, ­chemotherapy, radiation therapy, and targeted therapy.^1,4,5 The 5-year survival of GC patients with localized, regional, and distant-stage diseases are 67%, 31%, and 5%, respectively.^1,4,5The classical prognostic factors for GC include tumor size, lymphovascular invasion, nodal involvement, positive peritoneal cytology, signet ring cell adenocarcinoma,^1,2,4 age, sex,⁶ and obesity.^7,8 TNM (T: primary tumor, N: lymph node, M: distant metastasis) staging system and histopathological classification have been widely used as the prognostic tools for GC, which can help to formulate the treatment strategy.^1,4,5 However, their predictive ability remains limited.^9-11 Novel prognostic biomarkers are also being explored, with similar restrictions.^12-14 In recent years, several functional imaging methods such as computed tomography (CT) perfusion, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced magnetic resonance imaging have been developed. The stomach is a hollow moving organ filled with liquid and gas, and its motion may exacerbate artifacts, resulting in image distortion and ghosting. In addition, concerning the DWI sequence, susceptibility artifacts, distortions, and blurring are inevitable due to the slow traversal through the k-space line and the narrow bandwidth along the phase encoding direction.¹⁵ Among them, emerging radiomics is a promising prognostic tool for GC. Radiomics signatures, which compose of a series of CT texture features, are considered to be a stronger predictive factor, providing additional information beyond the traditional clinical factors.^16,17Previous studies examined the predictive value of radiomics in GC prognosis. A study showed that radiomics could predict recurrence-free survival (RFS) in locally advanced GC.¹⁸ Another radiomics-based model could predict lymphovascular invasion and progression-free survival (PFS) but not overall survival (OS).¹⁹ However, GC radiomics is still in its infancy, facing multiple challenges.²⁰Therefore, this study aimed to predict the disease-free survival (DFS) after GC surgery based on preoperative CT-enhanced images combined with clinical features. The results may help to improve the ability to predict DFS after gastrectomy.     

Establishment of a large animal model for research on transbronchial arterial intervention for lung cancer

PURPOSEWe aimed to evaluate whether bronchial artery can supply a percutaneously inoculated canine transmissible venereal tumor (CTVT) in a lung tumor model.METHODSFresh CTVT tissue blocks were percutaneously inoculated into unilateral or bilateral lungs of six immunosuppressed dogs at the mid zone of the middle or lower lobe. Tumor growth was monitored by computed tomography (CT). Ten weeks after inoculation, pulmonary arterial digital subtraction angiography (DSA), bronchial arterial DSA, transpulmonary arterial contrast-enhanced multislice CT, transbronchial arterial contrast-enhanced multislice CT (BA-MSCT), and transpulmonary arterial lipiodol multislice CT were performed.RESULTSTumor growth was seen in all 10 inoculated sites, with a maximum diameter of 2.734±0.138 cm at 10th week. Bronchial arterial blood supply was evident in 9 nodules on DSA, and was equivocal in one which was later demonstrated on BA-MSCT. No obvious pulmonary arterial blood supply was observed in any of the nodules. Lipiodol deposition was displayed in two of the small distant metastases, which indicated that pulmonary artery was involved in the supply of the metastases.CONCLUSIONOur results demonstrated bronchial arterial blood supply in this new lung cancer model. This model may be used in further research on transbronchial arterial intervention for lung cancer.

Bronchial arterial infusion chemotherapy (BAI) for lung cancer was introduced into clinical practice 50 years ago (1–3). Theoretically, better reductions in tumor size and symptoms, and less adverse effects of anticancer drugs could be achieved with direct infusion of high-density chemotherapeutics into tumors. However, BAI for lung cancer is not widely accepted. In the last two decades, only a few small case series were published in the English literature showing favorable results (4–9). This may be explained by several reasons: the outcomes have not been confirmed, severe complications have been reported (10, 11), the pharmacokinetics of BAI has not been fully understood, the indications and the treatment protocols have not been defined (4, 12). In the near future, the role of BAI or other transbronchial arterial therapy in the combined treatment of lung cancer may be reappraised, given the poor 5-year survival rate of less than 17% despite improvements in therapeutic management (13).Unfortunately, there is currently no large animal lung cancer model for fundamental research on transbronchial arterial therapy. In 2002, Ahrar et al. (14) developed a canine lung tumor model by intra-arterial or percutaneous inoculation of canine transmissible venereal tumor (CTVT) fragments, which was later used for study on percutaneous radiofrequency ablation (15). It is well known that metastatic lung cancer receives blood supply from both pulmonary artery and bronchial artery, with peripheral tumors having a predominant pulmonary circulation and central tumors having a predominant bronchial circulation (16). Our study goal is to evaluate the blood supply of this large animal lung tumor model.     

Assessment of complication rates based on time of feeding initiation in radiologically guided gastrostomy tubes: a retrospective study

PURPOSEWe aimed to assess the association between complication rate and time to feeding in a cohort of patients undergoing radiologically guided placement of gastrostomy tubes.METHODSA retrospective study was conducted of all patients receiving pull-type and push-type gastrostomy tubes placed by interventional radiologists between January 1^st, 2017 and December 31^st, 2018 at a single institution. Primary outcomes included procedural and tube-related complications per medical chart review with a follow-up interval of 30 days. Exclusion criteria were enteral nutrition delayed more than 48 hours, no feeding information, and tubes placed for venting (n=20). Overall, 303 gastrostomy tubes (pull-type, n=184; push-type, n=119) were included. The most common indications for placement included head and neck carcinoma for push-type tubes (n=76, 63.9%) and cerebral vascular accident for pull-type tubes (n=78, 42.4%).RESULTSIn a multiple regression analysis, there was no statistically significant association between complications and time to feeding (p = 0.096), age (p = 0.758), gender (p = 0.127), indication for tube placement (p = 0.206), or type of tube placed (p = 0.437). Average time to initiation of enteral nutrition was 12.3 hours for the pull-type and 21.7 hours for the push-type cohort (p < 0.001). Additional multiple regression analyses of pull-type tubes and push-type tubes separately also did not find any significant association between complications and the above factors (p > 0.05).CONCLUSIONThere was no statistically significant correlation between time to feed and complications, suggesting that there is no clinical difference between early and late feeding following gastrostomy tube placement.

Percutaneous radiologic gastrostomy is a well-established safe and effective feeding method (1–5). Early initiation of feeding after tube placement has several benefits, including decreased hospital stay and shorter time on intravenous nutrition, but the theoretical risk of increased complication rate has led many physicians to delay feeding initiation. While several studies have found that early initiation of feeding after tube placement is safe in the endoscopic literature (6–10), the association between time to feed and complications has been less frequently studied in the radiologic literature. Studies that have done so have been limited in the methods of tube placement included, sample size, and types of patients included (11, 12). Furthermore, despite evidence in the endoscopic literature, many physicians do not initiate early feeding after either endoscopic or radiologic gastrostomy placement (13).Within interventional radiology, the time to initiation of enteric feeding is one variable that remains discrepant between institutions and may pose consequence with respect to complications in the early post-placement setting (6–9, 11, 14, 15). Fora of interventional radiologists have demonstrated physicians are using a wide variety of fasting times following tube placement ranging from “early” (commonly less than 6 hours) to “delayed” (commonly 24 hours or greater) that is neither directly based on evidence nor guideline based (16). Furthermore, time to feeding following gastrostomy remains an important clinical metric that may impact initiation of therapy, feeding, and hospital discharge. The purpose of this study was to analyze the rate of feeding related complications in a cohort of all patients undergoing either “push” or “pull” type radiologic gastrostomy placement at a single institution based on time to initiation of feeding following tube placement.     

Digital breast tomosynthesis-based peritumoral radiomics approaches in the differentiation of benign and malignant breast lesions

PURPOSE We aimed to evaluate digital breast tomosynthesis (DBT)-based radiomics in the differentiation of benign and malignant breast lesions in women.METHODS A total of 185 patients who underwent DBT scans were enrolled between December 2017 and June 2019. The features of handcrafted and deep learning-based radiomics were extracted from the tumoral and peritumoral regions with different radial dilation distances outside the tumor. A 3-step method was used to select discriminative features and develop the radiomics signature. Discriminative clinical factors were identified by univariate logistic regression. The clinical factors with P < .05 were used to build a clinical model with multivariate logistic regression. The radiomics nomogram was developed by integrating the radiomics signature and discriminative clinical factors. Discriminative performance of the radiomics signature, clinical model, nomogram, and breast imaging reporting and data system assessment were evaluated and compared with the receiver operating characteristic and decision curves analysis (DCA).RESULTS A total of 2 handcrafted and 2 deep features were identified as the most discriminative features from the peritumoral regions with 2 mm dilation distances and used to develop the radiomics signature. The nomogram incorporating the radiomics signature, age, and menstruation status showed the best discriminative performance with area under the curve (AUC) values of 0.980 (95% CI, 0.960 to 1.000; sensitivity = 0.970, specificity = 0.946) in the training cohort and 0.985 (95% CI, 0.960 to 1.000; sensitivity = 0.909, specificity = 0.966) in the validation cohort. DCA confirmed the potential clinical usefulness of our nomogram.CONCLUSION Our results illustrate that the radiomics nomogram integrating the DBT imaging features and clinical factors (age and menstruation status) can be considered as a useful tool in aiding the clinical diagnosis of breast cancer.

Main points

1. The features of handcrafted and deep radiomics were extracted and analyzed from the digital breast tomosynthesis images of 185 patients.
2. The discriminative performance of tumoral and peritumoral regions was evaluated.
3. The discriminative performance of the clinical model, radiomics signature, and BI-RADS assessment was evaluated and compared. A radiomics nomogram incorporating the radiomics signature and important clinical factors (age and menstruation status) was developed for potential clinical applications.

Breast cancer is the most common cancer among females with fast-growing prevalence rates, accounting for approximately 30% of all cancer diagnoses.^1-3 Previous reports have demonstrated that early detection and timely treatment are key to the prognosis of breast cancer patients.⁴ In clinical practice, the most widely used early detection technique for breast tumor is standard X-ray mammography, due to its advantages of fast processing, low cost, and easy operation.⁵ However, the specificity and sensitivity of dense and heterogeneous breasts tend to significantly reduce because normal tissues can obscure the breast lesions, which cause limitations during visual examinations.⁴ In addition, structural disorder, which is also known as the early sign of breast cancer, is the most easily ignored false-negative sign in standard X-ray breast screenings, thus misleading the detection performance of early diagnosis.^6,7 In order to differentiate occlusions from the presence of other issues, the digital breast tomosynthesis (DBT) scanning has been applied widely for early-stage breast cancer screening,⁸ which employs rotating the X-ray tubes at a limited angle, thus allowing improved identification of anomalies obscured by normal breast tissue.⁹ Early studies have shown the DBT examination can effectively reduce false-positive and false-negative rates compared with traditional X-ray mammography on all breast density subtypes, especially on heterogeneously dense breasts,^10,11 and demonstrated great clinical values of DBT for breast cancer patients^12,13 The wide applications of DBT screenings have some limitations since well-experienced radiographers are needed during visual examination of DBT data to give clinical decisions by analyzing the morphological changes in the DBT image.¹⁴In recent years, radiomics has drawn increasing attraction in the fields of disease diagnosis, staging, and therapeutic response prediction because it makes precision medicine possible in a non-invasive manner by extracting and selecting high volumes of quantitative imaging features and revealing the features and the underlying pathophysiology.^15-19 Previous studies have demonstrated improvements in the detection performance of breast cancer using radiomics compared with those using visual examination by radiologists.^20-22 Recent reports have also highlighted the importance of radiomics in breast cancer diagnosis by breast mammography,^23,24 ultrasound,²⁵ magnetic resonance imaging,²⁶ and positron emission tomography/computed tomography,²⁷ although the reports on radiomics in breast DBT data are still limited.^13,28-30 The published studies have inherent limitations with limited feature types, limited number of patients, and lack of correlating their findings with clinical evaluation, which may further limit the clinical applicability. In this study, we evaluated the tumoral and peritumoral regions in the breast DBT image in differentiating malignant from benign lesions using handcrafted and deep features and developed a radiomics nomogram by integrating the radiomics signature and important clinical factors for facilitating early diagnosis of breast cancer.     

Prognostic role of iodine values for gastric cancer after neoadjuvant chemotherapy: a strong independent prognostic factor

PURPOSEWe aimed to systematically explore the value of iodine values calculated from dual-energy computed tomography (DECT) as potential prognostic factors for locally advanced gastric cancer (LAGC) patients undergoing neoadjuvant chemotherapy (NAC).METHODSEighty-five LAGC patients were examined using DECT before and after NAC and were divided into responders and non-responders based on the tumor regression grade (TRG). The iodine values including portal- and delayed-phase iodine uptake (IU_p and IU_d, mg/mL) and total iodine uptake (TIU_p and TIU_d, mg) were acquired. Correlations between the reduction ratios of iodine values and TRG were analyzed. The diagnostic performance of parameters for differentiating responders from non-responders was calculated. Kaplan–Meier method was used for survival analysis.RESULTSThe reduction ratios of total iodine uptake (%ΔTIU_p and %ΔTIU_d) were significantly correlated with TRG (P < .001). The ypN stage, %ΔTIU_p, and %ΔTIU_d were significant factors influencing progression-free survival (PFS) (P < .050). A value of %ΔTIU_d ≤ 62.19% was associated with negative prognosis [relative risk (RR):2.103; P = 0.021], as was ypN stage (RR: 4.250; P = .003).CONCLUSIONIodine values (especially the TIU) are noninvasive quantitative parameters that are potentially helpful for evaluating the treatment response and survival prognosis of LAGC after NAC. %ΔTIU_d represents a strong independent prognostic factor, increasing preoperative risk assessment performance.

Main points

• Iodine values (especially the total iodine uptake) are noninvasive quantitative parameters that are potentially helpful for evaluating the treatment response and survival prognosis of gastric cancer after neoadjuvant chemotherapy.
• The reduction ratio of total iodine uptake in the delayed phase represents a strong independent prognostic factor, increasing preoperative risk assessment performance.
• The reduction ratio of total iodine uptake can serve to guide patients toward individual treatment and predict the prognosis.

The incidence and mortality of gastric cancer (GC) are very high in the world.^1,2 Eighty to 90 percent³ of these patients were diagnosed as having locally advanced gastric cancer (LAGC), which has a poor prognosis primarily due to recurrence after surgery. Neoadjuvant chemotherapy (NAC) is a safe treatment modality that appears to have many advantages: it reduces tumor stage and size, increases the R₀ resection rate, and significantly improves survival.^4-6The assessment of prognosis after NAC can help to timely adjust the therapeutic regimens and to avoid potential toxicity. Therefore, the identification of preoperatively prognostic biomarkers is important. p53 codon 72 polymorphism⁷ in blood samples from LAGC patients after NAC and some immunohistochemistry biomarkers, such as thymidylate synthase,⁸ C-C motif chemokine 22,⁹ and orphan nuclear receptor,¹⁰ were considered to be independent prognostic factors. Other studies^11,12 found that immune-inflammation indicators are associated with survival. After assessing the clinical-pathologic variables (including ypT, ypN, ypTNM stage, complications, and perineural or vascular invasion),^10,13-15 lymph node status after NAC was established to be an independent prognostic factor. However, preoperative imaging prognostic factors of NAC, which identify the LAGC patients who are potential possibly to benefit from it, are limited at present.With the rapid development of imaging technology, dual-energy computed tomography (DECT) has become an important technological milestone. Specifically, it uses 2 acquisitions with X-ray spectra that differ in their mean photon energies to gain additional information on the scanned material. Based on the material decomposition algorithm from DECT,^16,17 quantitative material concentrations can be obtained, including iodine uptake (IU, mg/mL) and total iodine uptake (TIU, mg). Our previous research¹⁸ found that the reduction ratios of tumor TIU in the portal phase were helpful to predict the pathological regression and may be a valuable potential predictor of progression-free survival in LAGC after NAC. However, we only analyzed TIU in the portal phase. Along with an improvement in the vascular enhancement, the tumor contrast-to-noise ratio was remarkably improved. In addition, enhanced scanning showed that LAGC lesions were continuously enhanced layer by layer from inside to outside. Whether iodine values (IU and TIU) from the portal phase and delayed phase can be used as independent prognostic factors for LAGC patients after NAC has not yet been fully evaluated.Therefore, this study was aimed to systematically explore the value of iodine values calculated from DECT as potential prognostic factors for LAGC patients after NAC.     

MR angiography-planned prostatic artery embolization for benign prostatic hyperplasia: single-center retrospective study in 56 patients

PURPOSEWe aimed to evaluate the advantages of magnetic resonance angiography (MRA)-planned prostatic artery embolization (PAE) for benign prostatic hyperplasia (BPH).METHODSIn this retrospective study, MRAs of 56 patients (mean age, 67.23±7.73 years; age range, 47–82 years) who underwent PAE between 2017 and 2018 were evaluated. For inclusion, full information about procedure time and radiation values must have been available. To identify prostatic artery (PA) origin, three-dimensional MRA reconstruction with maximum intensity projection was conducted in every patient. In total, 33 patients completed clinical and imaging follow-up and were included in clinical evaluation.RESULTSThere were 131 PAs with a second PA in 19 pelvic sides. PA origin was correctly identified via MRA in 108 of 131 PAs (82.44%). In patients in which MRA allowed a PA analysis, a significant reduction of the fluoroscopy time (−27.0%, p = 0.028) and of the dose area product (−38.0%, p = 0.003) was detected versus those with no PA analysis prior to PAE. Intervention time was reduced by 13.2%, (p = 0.25). Mean fluoroscopy time was 30.1 min, mean dose area product 27,749 μGy·m², and mean entrance dose 1553 mGy. Technical success was achieved in all 56 patients (100.0%); all patients were embolized on both pelvic sides. The evaluated data documented a significant reduction in international prostate symptom scores (p < 0.001; mean 9.67 points).CONCLUSIONMRA prior to PAE allowed the identification of PA in 82.44% of the cases. MRA-planned PAE is an effective treatment for patients with BPH.

A profound knowledge about pelvic vessel anatomy is essential for achieving successful prostatic artery embolization (PAE), to improve the safety of PAE and to avoid major complications as non-target embolization (1–6). This knowledge can be achieved by using angiographic techniques to show pelvic artery anatomy, although the best method is still controversially discussed. In some studies, computed tomography (CT) angiography (CTA) was used for pre-interventional evaluation as it is described to have high certainty in analyzing prostatic artery (PA) anatomy (1, 3, 7). Other institutes use digital subtraction angiography (DSA) and cone beam CT (CBCT) for analysis without any pre-procedural vessel imaging (8–11). Since peri-interventional DSA findings may be ambiguous and CTA or CBCT would imply additional radiation, magnetic resonance angiography (MRA) seems to be a promising method to analyze PA origin without radiation. However, Maclean et al. (3) recommend CT for planning PAE instead of magnetic resonance imaging (MRI) as the latter is more expensive and more time-consuming. Pisco et al. (5, 12) state that MRA does not have enough resolution for clear identification of PA origin and does not provide the same information as CTA.Currently only a few studies discuss the suitability of MRA for preprocedural planning of PAE. Kim et al. (13) first investigated this subject with a sample size of 17 patients and documented an accuracy of 76.5% for PA origin analysis. However, in this study no clinical evaluation was included. Zhang et al. (4) investigated MRA analysis prior to PAE in a randomized clinical trial with 100 patients. A sensitivity of 91.5% and a significant reduction of procedure time, fluoroscopy time, radiation dose, and contrast medium volume due to pre-interventional MRA were documented. In his review, Prince (14) agrees with Zhang et al. (4) that MRA may be a suitable method for planning PAE.Because of the skeptical comments whether performing MRA prior to PAE is practical on a daily basis in a radiological institution, an assessment of these parameters in a less selective nature was necessary. In addition, contrary to Zhang et al. (4) who used MIP-reconstructions and 5° interval images for their assessment, we used a three-dimensional (3D) reconstruction of the pelvic arterial tree based on the MRA sequences. The main advantage of the 3D reconstruction is that it can be freely rotated in all directions which allowed an easy identification and tracking of the PA.In this study, the advantages and clinical outcome of pre-interventional analysis of PA via MRA as a possible radiation-free planning method and its influence on procedure time and radiation dose were investigated.     

MRI features of breast lymphoma: preliminary experience in seven cases

PURPOSE

We aimed to evaluate the imaging features of breast lymphoma using magnetic resonance imaging (MRI).

METHODS

This retrospective study consisted of seven patients with pathologically confirmed breast lymphoma. The breast lymphomas were primary in six patients and secondary in one patient. All patients underwent preoperative dynamic contrast-enhanced MRI and one underwent additional diffusion-weighted imaging (DWI) with a b value of 600 s/mm². Morphologic characteristics, enhancement features, and apparent diffusion coefficient (ADC) values were reviewed.

RESULTS

On MRI, three patients presented with a single mass, one with two masses, two with multiple masses, and one with a single mass and a contralateral focal enhancement. The MRI features of the eight biopsied masses in seven patients were analyzed. On MRI, the margins were irregular in six masses (75%) and spiculated in two (25%). Seven masses (87.5%) displayed homogeneous internal enhancement, while one (12.5%) showed rim enhancement. Seven masses (87.5%) showed a washout pattern and one (12.5%) showed a plateau pattern. The penetrating vessel sign was found in two masses (25%). One patient with two masses underwent DWI. Both masses showed hyperintense signal on DWI with ADC values of 0.867×10⁻³ mm²/s and 0.732×10⁻³ mm²/s, respectively.

CONCLUSION

Breast lymphoma commonly presents as a homogeneously enhancing mass with irregular margins and displays a washout curve pattern on dynamic MRI. A low ADC value may also indicate a possible diagnosis of breast lymphoma.Breast lymphoma, which constitutes only 0.04%–0.5% of all breast malignancies (1), can be divided into primary or secondary breast lymphoma (2). The majority of breast lymphomas are diffuse large B-cell lymphoma (3). The spontaneous regression of a breast lymphoma is rare and the five-year overall survival rate is 53% (1, 4). Early-stage identification and the use of radiotherapy are favorable prognostic factors, while mastectomy is associated with a poorer survival (1, 5). Therefore, a preoperative diagnosis of breast lymphoma would mean an earlier diagnosis and likely avoid unnecessary aggressive procedures.Previous studies demonstrated mammographic and ultrasonographic findings of breast lymphoma (6–8). Most lesions were high-density masses without spiculated margins and calcifications on mammography and noncircumscribed hypoechoic masses on ultrasonography (6–8). However, none were pathognomonic.Data on the magnetic resonance imaging (MRI) of breast lymphoma are limited to some single case reports (4, 7, 9–19) and small sample size case series (8, 20–23). The morphology and time-signal intensity curve (TIC) of breast lymphoma on MRI are variable. Diffusion-weighted imaging (DWI) is a functional imaging technique that is useful for distinguishing lymphoma from other malignant tumors in other systems (24, 25). However, to the best of our knowledge, the value of DWI in differentiating breast lymphoma from other malignant breast lesions has not been discussed. Therefore, the purpose of this study is to assess the MRI and DWI features of breast lymphoma.