Correlation of 18F-FDG PET/CT uptake with severity of MRI findings and epidural steroid injection sites in patients with symptomatic degenerative disease of the lumbar spine: a retrospective study

PURPOSEWe aimed to retrospectively correlate ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) metabolic activity with lumbar spine magnetic resonance imaging (MRI) findings and epidural steroid injection sites in patients with symptomatic degenerative disease of the lumbar spine.METHODSA database search was conducted for patients receiving epidural injections <12 months after a positron emission tomography/computed tomography (PET/CT). Maximum standard uptake values (SUVmax) were measured at the facet joints, neural foramina, and spinal canal. Severity of facet arthrosis, disc degeneration, neuroforaminal, and canal stenosis was determined on MRI using previously described grading scales. Spearman rank coefficient assessed association between PET/CT FDG uptake and severity of MRI findings. The SUVmax was also compared with injection sites.RESULTSTwenty-five patients were included, comprising MRI (n=19) and injection (n=22 patients; 18 interlaminar, 8 transforaminal) groups. Injections were performed an average of 2.6 months after PET/CT. The greatest SUVmax occurred at the L5-S1 spinal canal (mean SUVmax = 2.25). A statistically significant, positive correlation between uptake and grade of spinal canal stenosis was seen only at L4-L5 (r=0.60, p = 0.007). No other significant association was found with spinal canal or neuroforaminal stenosis, or grade of facet joint or disc degeneration. All patients reported symptomatic improvement after injections with mean pain score improvement of 4.4 on a 10-point scale (SD, 2.9). There was moderate agreement between sites of epidural injection and highest SUVmax (κ= 0.591, p < 0.001).CONCLUSION¹⁸F-FDG metabolic activity on PET/CT corresponds with MRI findings about the lumbar spinal column, but there is no significant correlation between severity of MRI findings and radiotracer uptake. Given the moderate agreement between metabolic activity and levels of symptomatic spinal stenosis, further studies are warranted to fully evaluate the diagnostic potential of FDG PET/CT as a surrogate for guiding epidural injections.

¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is useful to detect osseous metastases; however, uptake within the musculoskeletal system is frequently incidentally observed related to non-malignant degenerative or inflammatory disease 1–4). Chronic low back pain is extremely common worldwide, with a prevalence of 19.6% among people 20–59 years of age. Image-guided epidural steroid injections can be targeted to address symptomatic focal spinal stenosis (5, 6).Previous studies have examined incidental FDG uptake in the musculoskeletal system in general (1, 7–9) and the spine in particular (10–13), although few have systematically evaluated non-neoplastic uptake as it pertains to patient symptoms. Incidental FDG metabolic activity in the spine is most frequently due to degenerative etiologies involving the intervertebral discs or facet joints (11) with the most common site of uptake at the thoracolumbar junction (10, 13). Despite this, to our knowledge, no study has correlated patterns of radiotracer uptake with MRI findings and patient symptoms.The purpose of our study was therefore to detect possible correlations between FDG metabolic activity and severity of lumbar spine MRI findings as well as epidural injection sites among symptomatic patients.     

Evaluating the added benefit of CT texture analysis on conventional CT analysis to differentiate benign ovarian cysts

PURPOSEWe aimed to evaluate the benefit of adding CT texture analysis on conventional CT features of benign adnexal cystic lesions, especially in identifying mucinous cystadenoma.METHODSThis retrospective study included patients who underwent surgical removal of benign ovarian cysts (44 mucinous cystadenomas, 32 serous cystadenomas, 16 follicular/simple cysts and 43 endometriotic cysts) at our institution between January 2015 and November 2017. The CT images were independently reviewed by an abdominal radiologist (reviewer 1) and a resident (reviewer 2). Both reviewers recorded the conventional characteristics and performed texture analysis. Based on reviewer 1’s results, two decision trees for differential diagnosis were developed. Reviewer 2’s results were then applied to the decision trees. The diagnostic performances of each reviewer with and without the decision trees were compared.RESULTSSeveral conventional features and texture analysis parameters showed significant differences between mucinous cystadenomas and other benign adnexal cysts. The first decision tree selected septum number and thickness as significant features, whereas the second decision tree selected septum number and the mean values at spatial scaling factor (SSF) 0. Reviewer 1’s performance did not change significantly with or without the use of the decision trees. Reviewer 2’s interpretations were significantly less sensitive than reviewer 1’s interpretations (p = 0.001). However, when aided by the first and second decision trees, Reviewer 2’s interpretations were significantly more sensitive than reviewer 1’s interpretations (86.4%, p < 0.001; 72.7%, p = 0.001).CONCLUSIONThis study suggests the benefit of CT texture analysis on conventional images to differentiate mucinous cystadenoma from other benign adnexal cysts, particularly for less experienced radiologists.

In the assessment of a possible adnexal mass, it is paramount to differentiate benign lesions from malignancies, since their treatment strategies and prognoses drastically differ (1). Approaches to the lesions can even vary among different benign masses. Simple or follicular cysts do not require surgery at all, whereas epithelial tumors need to be resected for pathologic confirmation of their benignity and relief of the symptoms caused by mass effects. The treatment plan for endometriotic cysts varies based on the extent and severity of symptoms.Ultrasonography (US) is often the first imaging method performed in the evaluation of an ovarian lesion because it is widely available, well accepted by the patients, noninvasive and inexpensive (2). Magnetic resonance imaging (MRI) is an essential problem solving tool for characterizing an US-indeterminate adnexal mass, owing to its high resolution with excellent soft tissue contrast, possessing proven superiority over other modalities (1–4). Computed tomography (CT) is generally not intended for primary pelvic or gynecologic evaluation in women, unlike US or MRI (5). Its value in tumor characterization is limited by the detection of fat or calcifications within the lesion and the assessment of its rough shape, which may, but not necessarily, lead to a specific diagnosis (2, 3). In contrast to its suboptimal diagnostic value, recent widespread use of CT has commonly resulted in the incidental initial detection of an adnexal lesion (4–7).Common benign adnexal cystic lesions include functional cysts, serous cystadenomas, mucinous cystadenomas, and endometriotic cysts. Mucinous cystadenomas are characterized as multilocular cystic adnexal masses with variable internal mucinous contents and relatively large size at the time of presentation (2, 3, 8). As with most ovarian masses, it is challenging to make a specific diagnosis of mucinous cystadenoma and exclude other pathologic types, particularly when either US or CT is the only available modality. Two prior studies reported that the detection rates for mucinous cystadenoma using US, CT, and MRI were 50%, 62%, and 70%, respectively (9, 10). On MRI, mucinous tumors classically have a “stained glass appearance” with variable intralocular signal intensities, which allows a more specific differential diagnosis from other tumors than is possible with US and CT (2, 11). However, MRI is too costly and time-consuming to be performed routinely for incidentally found benign diseases.Recent advances in endoscopic surgical techniques have offered new possibilities for the laparoscopic treatment of large ovarian cysts, including mucinous cystadenomas, rather than laparotomy (12). The fluid content of a large cyst must be aspirated before it can be laparoscopically excised and removed (12). However, thick internal materials such as mucin or fat may impair this procedure. One reported case of laparoscopy had to be converted to open laparotomy due to an inability to aspirate the cyst’s liquid contents (13). The laparoscopic removal of large mucinous cystadenomas also poses the risk of spillage, which can cause pseudomyxoma peritonei (14–16). Therefore, it would be helpful to properly analyze the cyst’s internal contents and correctly preoperatively characterize the nature of the lesion to plan the surgery and avoid complications. Because of the limited availability of MRI, we evaluated the utility of CT with added texture analysis to differentiate the internal mucinous contents of ovarian cysts from serous fluid and eventually predict the pathologic diagnosis of the adnexal cystic lesion. Texture analysis is a method used to quantitatively evaluate pixel densities in medical images. Although texture analysis had been used in some previous studies on ovarian cancers, no study has performed texture analysis in ovarian cysts (17–19).Consequently, the purpose of this study is to evaluate the benefit of adding CT texture analysis to conventional CT features when diagnosing benign adnexal cystic lesions, and especially when identifying mucinous cystadenoma.     

Reduction of cardiac motion artifact in step-and-shoot coronary CT angiography with third-generation as compared with second-generation dual-source CT scanners

PURPOSEWe aimed to compare the effects of misregistration (stair-step artifact) occurrence during coronary computed tomography angiography (CCTA) using third- and second-generation dual-source computed tomography (DSCT) scanners.METHODSCCTA was performed in consecutive patients with suspected coronary heart disease. Patients were randomly assigned to two groups and imaged using a third-generation (n=68; group A) or second-generation (n=63; group B) DSCT scanner. Heart rate (HR), heart rate variability (HRV), the number of acquisition steps required, and the anatomical cardiac length of each patient were recorded and compared between the two groups. Qualitative interpretation and analyses were scored with respect to subjective image quality and misregistration (stair-step artifact) by two interpreters. Cohen’s kappa was used to evaluate the consistency between the observers.RESULTSAll CCTA images (100%) on both DSCT scanners yielded satisfactory image quality, with a subjective image quality score of 4.21±0.17. The consistency between the two observers with respect to misregistration and subjective scores were good (κ= 0.91 and 0.92, respectively). Both the number of acquisition steps required and the scan length of each patient in group A differed significantly (p < 0.001) from those in group B; there were significantly fewer artifacts in group A than in group B (p < 0.001). Misregistration artifacts did not correlate with the HRs or HRVs between two required acquisition steps (p > 0.20).CONCLUSIONAs compared with second-generation DSCT, the reduced number of acquisition steps required and the shorter scan length in third-generation DSCT reduced the occurrence of misregistration artifacts in CCTA images.

Coronary computed tomography angiography (CCTA) has gained widespread acceptance as the first choice for noninvasive assessment of a wide variety of cardiac diseases, as it has strong negative-predictive value and is effective in ruling out coronary artery disease in symptomatic patients, particularly those with intermediate risk (1). However, despite recent advances in cardiac computed tomography (CT) technologies, such as faster gantry rotation and an increased number of detector rows, CCTA images remain vulnerable to a number of artifacts due to patient- and technique-specific causes. Artifacts in cardiac CT may cause image degradation and interference in diagnosis (2–4), leading to either underdiagnosis or overtreatment, both of which are associated with increased patient morbidity and mortality (5).Misregistration (stair-step) artifact, a type of cardiac motion artifact, appears when the heart is not in an identical position during consecutive heartbeats, because of arrhythmias (5). Avoiding misregistration artifacts between adjacent acquisition steps remains a challenge in step-and-shoot CCTA (6). Numerous studies have investigated step-and-shoot CCTA with different types of CT scanners. A previous study investigated misregistration artifacts with a 64-slice single-source CT (7), another study investigated image quality obtained with 128-slice dual-source CT (DSCT) (8), while yet another study investigated the effect of heart rate (HR) and heart rate variability (HRV) on image quality when using a 256-slice CT scanner (6). Most guidelines state that decreasing the mean HR and HRV is the most important factor for minimizing cardiac motion artifacts (9, 10), including misregistration artifacts. However, it is not clear whether the incidence of misregistration artifacts would be similar in the new-generation DSCT scanners, with their faster gantry speed and increased Z-coverage.Hence, the aim of this study was to investigate the frequency of occurrence of misregistration artifacts in step-and-shoot CCTA with a third-generation DSCT scanner, as compared with that of a second-generation DSCT scanner.     

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.     

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.     

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.     

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.     

Spin-echo and diffusion-weighted MRI in differentiation between progressive massive fibrosis and lung cancer

PURPOSEWe aimed to investigate the value of magnetic resonance imaging (MRI)-based parameters in differentiating between progressive massive fibrosis (PMF) and lung cancer.METHODSThis retrospective study included 60 male patients (mean age, 67.0±9.0 years) with a history of more than 10 years working in underground coal mines who underwent 1.5 T MRI of thorax due to a lung nodule/mass suspicious for lung cancer on computed tomography. Thirty patients had PMF, and the remaining ones had lung cancer diagnosed histopathologically. The sequences were as follows: coronal single-shot turbo spin echo (SSH-TSE), axial T1- and T2-weighted spin-echo (SE), balanced turbo field echo, T1-weighted high-resolution isotropic volume excitation, free-breathing and respiratory triggered diffusion-weighted imaging (DWI). The patients’ demographics, lesion sizes, and MRI-derived parameters were compared between the patients with PMF and lung cancer.RESULTSApparent diffusion coefficient (ADC) values of DWI and respiratory triggered DWI, signal intensities on T1-weighted SE, T2-weighted SE, and SSH-TSE imaging were found to be significantly different between the groups (p < 0.001, for all comparisons). Median ADC values of free-breathing DWI in patients with PMF and cancer were 1.25 (0.93–2.60) and 0.76 (0.53–1.00) (× 10⁻³ mm²/s), respectively. Most PMF lesions were predominantly iso- or hypointense on T1-weighted SE, T2-weighted SE, and SSH-TSE, while most malignant ones predominantly showed high signal intensity on these sequences.CONCLUSIONMRI study including SE imaging, specially T1-weighted SE imaging and ADC values of DWI can help to distinguish PMF from lung cancer.

Pneumoconiosis, defined as the accumulation of inhaled particles is relatively common in industrial areas (1). Coal worker’s pneumoconiosis, silicosis, and asbestosis are the most common forms of pneumoconiosis (2). Progressive massive fibrosis (PMF) of the lung is defined as a combination of anthracosilicotic nodules and connective tissue, and it may be seen in the chronic stage of pneumoconiosis (1).The imaging features of PMF on chest radiography and computed tomography (CT) have been well investigated (3, 4). The main characteristic finding of PMF on CT is an irregular nodule or mass with or without calcification, located mostly in the upper and middle lung zones (5). However, it is occasionally difficult to distinguish PMF from lung cancer due to a similar appearance on these imaging modalities as well as similar clinical presentation. The differentiation is especially difficult, when PMF lesion appears as a mass or mass-like lesion and grows in size during the follow-up. Additionally, lung cancer may be seen together with underlying PMF lesion. 18F-fluoro-2-deoxy-D-glucose positron emission tomography/CT (¹⁸F-FDG PET/CT) can be used in differentiation between PMF and lung cancer but it may not be helpful in some cases (6).Magnetic resonance imaging (MRI) with high conrast resolution and additional diignostic facility tools may be helpful in terms of avoiding biopsy and its possible complications in the differentiation between PMF and lung cancer (7, 8). A low signal intensity (SI) on T2-weighted MRI and a gradual increase in SI in a dynamic MRI study are the reported, characteristic MRI findings of PMF (9, 10). However, the use of several MRI sequences has not yet been fully explored for the differentiation between PMF and lung cancer. In addition to the SI changes, assessment of quantitative MRI parameters could also be helpful in the differentiation of these entities. The purpose of this study was to investigate the value of MRI-based parameters in differentiating between PMF and lung cancer.     

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.     

Antireflux catheter improves tumor targeting in liver radioembolization with resin microspheres

PURPOSEWe aimed to determine whether antireflux (ARC) catheter may result in better tumor targeting in liver radioembolization using ⁹⁰Y-resin microspheres.METHODSPatients treated with resin microspheres for hepatocellular carcinoma (HCC) and secondary liver malignancies were retrospectively analyzed. All patients underwent a ^99mTc-macroaggregated albumin (^99mTc-MAA) single photon emission computed tomography (SPECT) following the planning arteriography with a conventional end-hole catheter. For ⁹⁰Y-microspheres injection, two groups were defined depending on the type of catheter used: an ARC group (n=38) and a control group treated with a conventional end-hole catheter (n=23). ⁹⁰Y positron emission tomography computed tomography (PET/CT) was performed after the therapeutic arteriography. The choice of the catheter was not randomized, but left to the choice of the interventional radiologist. ^99mTc-MAA SPECT and ⁹⁰Y PET/CT were co-registered with the baseline imaging to determine a tumor to normal liver ratio (T/NL_{[MAA or 90Y]}) and tumor dose (TD_{[MAA or 90Y]}) for the planning and therapy.RESULTSOverall, 38 patients (115 lesions) and 23 patients (75 lesions) were analyzed in the ARC and control groups, respectively. In the ARC group, T/NL_90Y and TD_90Y were significantly higher than T/NL_MAA and TD_MAA. Median (IQR) T/NL_90Y was 2.16 (2.15) versus 1.74 (1.43) for T/NL_MAA (p < 0.001). Median (IQR) TD_90Y was 90.96 Gy (98.31 Gy) versus 73.72 Gy (63.82 Gy) for TD_MAA (p < 0.001). In this group, the differences were highly significant for neuroendocrine metastases (NEM) and HCC and less significant for colorectal metastases (CRM). In the control group, no significant differences were demonstrated.CONCLUSIONThe use of an ARC significantly improves tumor deposition in liver radioembolization with resin microspheres.

Yttrium-90 (⁹⁰Y) radioembolization is a locoregional therapy for hepatocellular carcinoma (HCC) and secondary liver malignancies. ⁹⁰Y-loaded microspheres are injected in the liver target volume (containing tumors) during arterial catheterization. This treatment aims at reaching an efficient absorbed dose to tumors while minimizing radiation dose to the healthy liver in order to prevent toxicity (1).Before treatment, a planning arteriography is always performed for evaluating the feasibility of radioembolization. For this purpose, the treatment is simulated with intra-arterial injection of ^99mTc-macroaggregated albumin (MAA) particles (2). Afterwards, ⁹⁹Tc-MAA nuclear imaging is performed to estimate lung shunt, for ruling out extrahepatic deposition and for dosimetry calculations (3, 4). Previous studies demonstrated a strong relationship between the tumor dose evaluated on ^99mTc-MAA single photon emission computed tomography (SPECT) imaging and the tumor response, especially for HCC (3).Better tumor targeting is a real challenge to improve clinical results of radioembolization. An increase in the tumor dose leads to an increase in the tumor control probability and in patient outcome (5). The technique has evolved recently, especially in the field of interventional radiology, for instance by the use of cone beam computed tomography (CT) for accurate planning or by using special microcatheters, such as antireflux catheters (ARC), i.e., Surefire Infusion System^® (Surefire Medical Inc.). ARC has a funnel shaped expanding tip designed to minimize reflux of radioactive microspheres and the risk of extrahepatic deposition (6, 7). Changes in the downstream hepatic arterial blood pressure were reported using this catheter (8). When the ARC is deployed, the arterial blood pressure decreases in the antegrade distribution and may reduce the resistance in the tumor vasculature. This hemodynamic effect seems responsible for an increase in tumor targeting in some previous reports (9, 10).Our study aims to compare tumor to normal liver ratio (T/NL) and tumor absorbed doses (TD) when a conventional end-hole catheter (EHC) and an ARC are used in the same patient at two different time points. As a second endpoint, we investigated this effect as a function of the tumor type.     

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.     

Patient doses from CT examinations in Turkey

PURPOSE

We aimed to establish the first diagnostic reference levels (DRLs) for computed tomography (CT) examinations in adult and pediatric patients in Turkey and compare these with international DRLs.

METHODS

CT performance information and examination parameters (for head, chest, high-resolution CT of the chest [HRCT-chest], abdominal, and pelvic protocols) from 1607 hospitals were collected via a survey. Dose length products and effective doses for standard patient sizes were calculated from the reported volume CT dose index (CTDI_vol).

RESULTS

The median number of protocols reported from the 167 responding hospitals (10% response rate) was 102 across five different age groups. Third quartile CTDI_vol values for adult pelvic and all pediatric body protocols were higher than the European Commission standards but were comparable to studies conducted in other countries.

CONCLUSION

The radiation dose indicators for adult patients were similar to those reported in the literature, except for those associated with head protocols. CT protocol optimization is necessary for adult head and pediatric chest, HRCT-chest, abdominal, and pelvic protocols. The findings from this study are recommended for use as national DRLs in Turkey.Computed tomography (CT) scanners have been used in diagnostic radiology since the early 1970s and have gained popularity worldwide owing to their substantial and life-saving clinical benefits. However, the increase in the use of CT applications has led to the emergence of radiologic concerns, such as cancer risk, because of the incremental collective effective dose (ED) associated with its use. Even if the number of CT exams is small among all radiography procedures, a large proportion of medical radiation exposure comes from CT applications. CT contributes the biggest part of radiation from medical sources in the United States (~66%), United Kingdom (~47%), and Germany (~60%) (1, 2). Owing to these concerns, protection of patients of all age groups from the effects of unnecessary and harmful radiation has become a priority in CT examinations (1–3).Dose constraint is one of the fundamental radiation protection principles; however, this cannot be applied in radiologic examinations (3). Therefore, the optimization principle has become increasingly important and needs to be performed with considerable attention in medical practice. Comparison of CT application parameters and patient radiation doses with diagnostic reference levels (DRLs) is a recommended method often considered the first step for optimization in CT examinations (4). Medical practitioners utilize national DRLs as an indicator of dose, in accordance with hospital CT protocols. When patient doses exceed the national DRL, CT examinations should be re-evaluated and optimized (5). The establishment of DRLs for individual countries has been recommended by international organizations such as the International Commission on Radiological Protection (ICRP) and the European Commission (EC) (6–8).The justification of CT examinations may necessitate the willingness of radiology personnel to participate in decision-making regarding the use of radiographic examinations; however, more important input may be derived from the optimization of scanning protocols. Patient radiation doses originating from radiologic examinations can exhibit large variations, even when they are performed in the same hospital department (9, 10). The existence of DRLs for specific radiologic examinations enables standardization across the majority of patients. However, DRLs are neither realistic boundaries for CT technicians nor are they regarded as an indicator of good medical practice. Determination of actual dose levels for targeted patient groups and attempts to maintain radiation exposure below the DRLs may reduce the detrimental health effects associated with radiologic procedures (11, 12).A recent study performed in Turkey investigated patients who underwent CT examinations while pregnant, unbeknownst to the patient and technicians. Mean patient radiation doses from abdominal CT examinations were reported to be approximately three-fold higher than those published in the literature (13). Therefore, there is an urgent need for establishment of national DRLs and for the optimization of CT scanning protocols. In 2012, there were more than 1600 CT devices used in Turkey and a technical report from the country’s national authority revealed that there is insufficient information concerning radiation doses from CT devices (14).     

Traumatic diaphragmatic injury: a review of CT signs and the difference between blunt and penetrating injury

PURPOSE

We aimed to present the frequency of computed tomography (CT) signs of diaphragmatic rupture and the differences between blunt and penetrating trauma.

MATERIALS AND METHODS

The CT scans of 23 patients with surgically proven diaphragmatic tears (both blunt and penetrating) were retrospectively reviewed for previously described CT signs of diaphragmatic injuries. The overall frequency of CT signs was reported; frequency of signs in right- and left-sided injuries and blunt and penetrating trauma were separately tabulated and statistically compared.

RESULTS

The discontinuous diaphragm sign was the most common sign, observed in 95.7% of patients, followed by diaphragmatic thickening (69.6%). While the dependent viscera sign and collar sign were exclusively observed in blunt-trauma patients, organ herniation (P = 0.05) and dangling diaphragm (P = 0.0086) signs were observed significantly more often in blunt trauma than in penetrating trauma. Contiguous injury on either side of the diaphragm was observed more often in penetrating trauma (83.3%) than in blunt trauma (17.7%).

CONCLUSION

Knowledge of the mechanism of injury and familiarity with all CT signs of diaphragmatic injury are necessary to avoid a missed diagnosis because there is variability in the overall occurrence of these signs, with significant differences between blunt and penetrating trauma.Traumatic diaphragmatic injury has been found in 3%–8% of patients undergoing surgical exploration after blunt trauma and in 10% of patients with penetrating trauma (1, 2). The rate of initially missed diagnoses on computed tomography (CT) ranges from 12% to 63%. A missed diagnosis can later present as intrathoracic visceral herniation and strangulation with a mortality rate of 30%–60% (2, 3). In this era of increasing nonoperative management for most cases of blunt abdominal trauma, it becomes essential to diagnose diaphragmatic rupture on imaging to ensure early and timely operative repair of the rupture. The reasons for missed early diagnoses include potentially distracting and more severe thoracic and abdominal visceral injuries and lack of familiarity with all the imaging appearances and signs of diaphragmatic rupture (2, 4).Various imaging modalities including chest radiographs, ultrasonography, CT, and magnetic resonance imaging have been used in the diagnosis of diaphragmatic rupture (1). Currently, multidetector CT (MDCT) is the modality of choice for the detection of diaphragmatic injury. MDCT has increased the accuracy of diagnosis of diaphragmatic rupture. MDCT has inherent technical advantages, such as rapid, volumetric data acquisition for the chest and abdomen within a single breath hold, minimization of motion artifacts, thin-section reconstruction and sagittal and coronal reformat-reducing partial-volume effects that assist in diagnosing subtle defects (1). MDCT also aids in detecting the associated chest, abdomen, ribs, and bony injuries in these polytrauma patients. Various studies have revealed CT to have a variable sensitivity and specificity of 61%–87% and 72%–100%, respectively, for the diagnosis of diaphragmatic rupture (1, 5–7). Killeen et al. (6) demonstrated that the sensitivity for detecting left-sided ruptures (78%) is higher than for right-sided ruptures (50%). This finding has been attributed to the better soft tissue-fat contrast on the left side and the difficulty in diagnosing subtle liver herniation on the right side.Various signs of diaphragmatic rupture have been described on CT. These signs have been divided into direct and indirect signs and signs of uncertain/controversial origin, according to Desir and Ghaye (8), and have been tabulated in 2, 3).

Table 1.

CT signs of diaphragmatic injury^a

Evaluation of repeat distal transradial access in the anatomic snuffbox

PURPOSEThere is increasing interest in the distal radial artery in the anatomic snuffbox as an alternative arterial access point, but the durability of the distal radial artery to support repetitive accesses over multiple procedures is not well established. The purpose of this study was therefore to evaluate success rates for repeated left-sided distal transradial access (ldTRA) in the anatomic snuffbox.METHODSIn this single institution retrospective study, all patients undergoing radioembolization treatments from January 1st, 2019 to May 1st, 2020 were prospectively evaluated for ldTRA. ldTRA was performed by 15 different operators. Exclusion criteria were a left radiocephalic hemodialysis fistula, inability to properly position the arm, Barbeau D waveform, or failed prior ldTRA due to tortuosity. Barbeau patterns, arterial sizes, and success rates at the first, second, and third ldTRA were compared.RESULTSFifty patients were evaluated for ldTRA and 44, 39, and 10 underwent one, two, and three ldTRA attempts for a total of 93 procedures. There was no significant change in Barbeau patterns between the first and second (p = 0.13) or first and third (p = 1.0) ldTRA. There was no significant change in artery size between the first (mean, 2.3 mm; range, 1.5–3.4 mm) and second (mean, 2.3 mm; range, 1.6–3.3 mm) (p = 0.59) and first and third (mean, 2.4 mm; range, 1.9–3.3) (p = 0.45) ldTRA. The success rate was not significantly different between the first (93%, 41/44, 95% CI 81%–99%), second (95%, 37/39, 95% CI 83%–99%), and third (100%, 10/10, 95% CI 69%–100%) procedure (p = 1.0). The asymptomatic occlusion rate was 4.1% (2/49, 95% CI 0%–14%), and subsequent ldTRA was successfully completed in both patients with occlusions. There were no hemorrhagic or ischemic complications.CONCLUSIONSuccess rates are indistinguishable among first, second, and third time ldTRA suggesting that this is a durable access point.

The radial artery has been established as a favorable arterial access point for endovascular procedures, with the potential benefits of reduced risk of complications (1) and increased patient comfort (2, 3) compared with the common femoral artery. As an extension to conventional transradial access (cTRA) upstream of the radial styloid, there has recently been interest in distal transradial access (dTRA) in the anatomic snuffbox as an alternative radial artery access point (4, 5).For interventional radiologists several benefits of left-sided distal transradial access (ldTRA) have been proposed. ldTRA with the patient’s hand across the lower abdomen simulates the positioning of right common femoral artery access, a potentially more ergonomic configuration for operators used to working right-handed (6). In this location, the left arm is tucked across the body in a more compact position for cone beam computed tomography (CT) (4). Beyond these ergonomic considerations, it has been suggested that dTRA may reduce the risk of injury to the palmar arch compared with cTRA (4) although this remains to be shown empirically (5).One limitation of dTRA compared with cTRA is that dTRA is less extensively studied. In particular, the durability of this slightly smaller (4) access point which is associated with a slightly higher failure rate (5, 7) for repeat procedures is not well established. Although the occlusion rate is reportedly low (5), few studies have specifically reported outcomes for repeated ldTRA attempts (6, 8).The purpose of this study was to evaluate success rates for repeated left-sided distal transradial access in the anatomic snuffbox.     

Efficacy of CT in diagnosis of transudates and exudates in patients with pleural effusion

PURPOSE

We aimed to evaluate the efficacy of multidetector computed tomography (CT) imaging in diagnosis of pleural exudates and transudates using attenuation values.

MATERIALS AND METHODS

This retrospective study included 106 patients who were diagnosed with pleural effusion between January 2010 and June 2012. After the patients underwent chest CT, thoracentesis was performed in the first week. The attenuation values of the pleural effusions were measured in all patients.

RESULTS

According to Light’s criteria, 30 of 106 patients with pleural effusions had transudates, and the remaining patients had exudates. The Hounsfield unit (HU) value of the exudates (median, 12.5; range, 4–33) was significantly higher than that of the transudates (median, 5; range, 2–15) (P = 0.001). Additionally, when evaluated by disease subgroups, congestive heart failure and empyema were predictable in terms of median HU values of the pleural effusions with high and moderate sensitivity and specificity values (84.6% and 81.2%, respectively; 76.9% and 66.7%, respectively). Compared with other patients, the empyema patients had significantly more loculation and pleural thickening.

CONCLUSION

CT attenuation values may be useful in differentiating exu-dates from transudates. Although there is an overlap in most effusions, exudate can be considered when the CT attenuation values are >15 HU. Because of overlapping HU values, close correlation with clinical findings is essential. Additional signs, such as fluid loculation and pleural thickness, should be considered and may provide further information for the differentiation.Pleural effusion is a common clinical problem; indeed, it can arise from many diseases (1, 2). The first step in assessing a pleural effusion is to decide whether the pleural fluid is a transudate or an exudate (3). Transudate is caused by imbalances in hydrostatic and oncotic forces. It results from diseases such as heart failure, kidney failure, and cirrhosis. However, an exudate occurs when local factors influencing the accumulation of pleural fluid are altered. Exudates can be caused by clinical conditions such as pneumonia, malignancy, and thromboembolism (4).Although clinical and radiological findings may provide significant evidence about the cause(s) of pleural effusion(s), it may still be necessary to evaluate some cases with diagnostic thoracentesis (4, 5). Clinically, exudative effusion can be successfully separated from transudative effusion using Light’s criteria. The nature of the pleural effusion is based on diagnostic thoracentesis (1, 2). However, computed tomography (CT) can be used to evaluate the nature of pleural effusions to avoid the complications of thoracentesis (6, 7). Features such as pleural nodules, pleural thickening, loculation, extrapleural fat tissue thickness, and effusion density can be evaluated by CT to discriminate between exudates and transudates (8). Only two reported studies have examined CT attenuation values in patients with pleural effusions (9, 10); these showed different attenuation values for evaluation of pleural effusions.The aim of the present study was to evaluate the efficacy of multidetector CT (MDCT) images in diagnosing pleural exudates and transudates using attenuation values.     

Adverse effects of irreversible electroporation of malignant liver tumors under CT fluoroscopic guidance: a single-center experience

PURPOSE

We aimed to describe the frequency of adverse events after computed tomography (CT) fluoroscopy-guided irreversible electroporation (IRE) of malignant hepatic tumors and their risk factors.

METHODS

We retrospectively analyzed 85 IRE ablation procedures of 114 malignant liver tumors (52 primary and 62 secondary) not suitable for resection or thermal ablation in 56 patients (42 men and 14 women; median age, 61 years) with regard to mortality and treatment-related complications. Complications were evaluated according to the standardized grading system of the Society of Interventional Radiology. Factors influencing the occurrence of major and minor complications were investigated.

RESULTS

No IRE-related death occurred. Major complications occurred in 7.1% of IRE procedures (6/85), while minor complications occurred in 18.8% (16/85). The most frequent major complication was postablative abscess (4.7%, 4/85) which affected patients with bilioenteric anastomosis significantly more often than patients without this condition (43% vs. 1.3%, P = 0.010). Bilioenteric anastomosis was additionally identified as a risk factor for major complications in general (P = 0.002). Minor complications mainly consisted of hemorrhage and portal vein branch thrombosis.

CONCLUSION

The current study suggests that CT fluoroscopy-guided IRE ablation of malignant liver tumors may be a relatively low-risk procedure. However, patients with bilioenteric anastomosis seem to have an increased risk of postablative abscess formation.About 70% of hepatic metastases are nonresectable because of their anatomic location, the presence of comorbidities, or limited hepatic functional reserve (1). In these patients and in case of nonresectable primary liver tumors, percutaneous thermal ablation procedures, such as radiofrequency (RF) and microwave ablation, have become effective tools for treating hepatic malignancies (2–4). However, the effectiveness of RF and microwave treatment may be limited, either because of thermal damage to temperature-sensitive structures located in close proximity to the target tissue (5) or because of incomplete ablation of tumors adjacent to major hepatic vessels due to a phenomenon commonly termed “heat-sink effect” (6–10) which describes the loss of the applied thermal energy through the blood flow in those major vessels, whereby the effective energy application remains inadequate to ablate the target lesion.Irreversible electroporation (IRE) is a theoretically nonthermal ablation technique that delivers a series of high-voltage millisecond electrical pulses to the surrounding tissue, thus leading to irreversible disruption of the integrity of cell membranes and subsequent cell death by apoptosis (11–14). IRE may overcome the problems raised with thermal ablation: previous animal studies reported that bile ducts, blood vessels, nerves, and connective tissues are affected by IRE; however, regeneration is possible to some extent due to preservation of the tissue architecture (12, 13, 15–19). Moreover the feasibility of inducing cell death up to a vessel wall without any perivascular sparing was shown with IRE (12, 13, 18). The safety of IRE in the treatment of humans has been described (20). First reports have described potential complications after IRE, such as hemorrhage requiring blood transfusion (1.2%, two of 167 ablation procedures), portal vein thrombosis (3.2%, one of 31 ablation procedures), injury to bile ducts (1.8%, three of 167 ablation procedures), and infection (3.6%, six of 167 ablation procedures) (21, 22). However, few data are available for evaluating the potential risk factors associated with the occurrence of post-IRE complications.The purpose of this study was to review the frequency of mortality and morbidity after computed tomography (CT) fluoroscopy-guided liver IRE conducted at a single center and assess the factors influencing the occurrence of major complications.     

Adrenal venous sampling for stratifying patients for surgery of adrenal nodules detected using dynamic contrast enhanced CT

PURPOSE

We aimed to assess the value of adrenal venous sampling (AVS) for diagnosing primary aldosteronism (PA) subtypes in patients with a unilateral nodule detected on adrenal computed tomography (CT) and scheduled for adrenalectomy.

MATERIALS AND METHODS

This retrospective study included 80 consecutive patients with PA undergoing CT and AVS. Different lateralization indices were assessed, and a cutoff established using receiver operating characteristic curve analysis. The value of CT alone versus CT with AVS for differentiating PA subtypes was compared. The adrenalectomy outcome was assessed, and predictors of cure were determined using univariate analysis.

RESULTS

AVS was successful in 68 patients. A cortisol-corrected aldosterone affected-to-unaffected ratio cutoff of 2.0 and affected-to-inferior vena cava ratio cutoff of 1.4 were the best lateralization indices, with accuracies of 82.5% and 80.4%, respectively. CT and AVS diagnosed 38 patients with aldosterone-producing adenomas, five patients with unilateral adrenal hyperplasia, and 25 patients with bilateral adrenal hyperplasia. Of the 52 patients with a nodule detected on CT, subsequent AVS diagnosed bilateral adrenal hyperplasia in 14 patients (27%). Compared to the results of combining CT with AVS, the accuracy of CT alone for diagnosing aldosterone-producing adenomas was 71.1% (P < 0.001). The cure rate for hypertension after adrenalectomy was 39.2%, with improvement in 53.5% of patients. On univariate analysis, predictors of persistent hypertension were male gender and preoperative systolic blood pressure.

CONCLUSION

To avoid inappropriate surgery, AVS is necessary for diagnosing unilateral nodules with aldosterone hypersecretion detected by CT.Primary aldosteronism (PA) is the most common form of secondary hypertension, with a prevalence of 5%–11% (1–3). PA is due primarily to the hypersecretion of aldosterone by an aldosterone-producing adenoma (APA) or unilateral (primary) adrenal hyperplasia (UAH), which constitute 30%–40% of cases; the remainder are presumed to be secondary to idiopathic bilateral adrenal hyperplasia (BAH) (1, 4, 5). APA and UAH are two forms of unilateral aldosterone hypersecretion, and both are curable with adrenalectomy. BAH induces bilateral aldosterone hypersecretion, and anti-aldosterone drugs are used in its medical management (5–7).The plasma aldosterone-to-renin ratio is used to screen for PA in patients at high risk for PA (8). Recent guidelines recommend using computed tomography (CT) of the adrenal gland to categorize the subtype after confirming PA. However, CT cannot reliably visualize a microadenoma or distinguish between an incidentaloma or BAH and APA. It has been suggested that adrenal venous sampling (AVS) be performed to determine the subtype of PA and to differentiate between unilateral and bilateral production of aldosterone preoperatively (9). AVS to measure the adrenal vein aldosterone and cortisol is the gold standard for lateralizing aldosterone secretion (10). Lateralization is defined using several ratios. In patients with APA or UAH, a unilateral adrenalectomy results in a complete cure or improved hypertension and potassium normalization in approximately 30% of patients, with reported rates up to 86% (11–15).This study assessed several lateralization ratios to establish the most predictive of unilateral disease. We also compared the CT results with those of bilateral AVS for differentiating the PA subtype, with the assumption that AVS is necessary before surgery, even in patients with nodules <10 mm detected with CT. Finally, we assessed the outcomes of adrenalectomy in our patients to identify preoperative predictors of a good outcome.