PET/CT in the management of differentiated thyroid cancer

The standard treatment of differentiated thyroid cancer (DTC) consists of surgery followed by iodine-131 (¹³¹I) administration. Although the majority of DTC has a very good prognosis, more aggressive histologic subtypes convey a worse prognosis. Follow-up consists of periodically measurements of serum thyroglobulin, thyroglobulin antibodies and neck ultrasound and ¹²³I/¹³¹I whole-body scan. However, undifferentiated thyroid tumors have a lower avidity for radioiodine and the ability of DTC to concentrate ¹³¹I may be lost in metastatic disease. Positron emission tomography (PET)/computed tomography (CT) has been introduced in the evaluation of patients with thyroid tumors and the 2-[18F]-fluoro-2-deoxyd-glucose (¹⁸F-FDG) has been largely validated as marker of cell's metabolism. According to the 2015 American Thyroid Association guidelines, ¹⁸F-FDG PET/CT is recommended in the follow-up of high-risk patients with elevated serum thyroglobulin and negative ¹³¹I imaging, in the assessment of metastatic patients, for lesion detection and risk stratification and in predicting the response to therapy. It should be considered that well-differentiated iodine avid lesions could not concentrate ¹⁸F-FDG, and a reciprocal pattern of iodine and ¹⁸F-FDG uptake has been observed. Beyond ¹⁸F-FDG, other tracers are available for PET imaging of thyroid tumors, such as Iodine-124 (¹²⁴I), ¹⁸F-tetrafluoroborate and Gallium-68 prostate-specific membrane antigen. Moreover, the recent introduction of PET/MRI, offers now several opportunities in the field of patients with DTC. This review summarizes the evidences on the role of PET/CT in management of patients with DTC, focusing on potential applications and on elucidating some still debating points.     

18F-FDG PET/CT评价非霍奇金淋巴瘤骨髓浸润

目的探讨^18F-FDG PET／CT评价非霍奇金淋巴瘤（NHL）骨髓浸润的临床应用价值,并与骨髓活检（BMB）及流式细胞分析（FCM）进行比较。方法回顾性分析89例经病理证实且未经治疗的NHL患者^18F-FDG PET／CT资料,其中侵袭性NHL76例,惰性NHL13例。所有患者均在^18F-FDG PET／CT检查2周内接受BMB及FCM,对^18F-FDG PET／CT显示骨髓局灶性^18F—FDG摄取增高而BMB及FCM阴性患者,根据PET／CT所示骨髓异常部位再次行BMB确定骨髓是否受累。结果89例NHL患者中,根据BMB、FCM及PET／CT引导下再次BMB结果,共检出骨髓浸润26例,检出率为29．21％（26／89）,PET／CT检出率为21．35％（19／89）。PET／CT诊断骨髓浸润的灵敏度为73．08％（19／26）,特异度为96．83％（61／63）,准确率为89．89％（80／89）,阳性预测值为90．48％（19／21）,阴性预测值为89．71％（61／68）。BMB及FCM检出率均为19．10％（17／89）,PET／CT较BMB、FCM骨髓浸润检出率稍高,但差异无统计学意义（P〉0．05）。将PET／CT、FCM及BMB三种方法联合诊断骨髓浸润,其检出率高于其中任意一种方法（P〈0．05）。PET／CT对侵袭性NHL骨髓浸润的检出率22．37％（17／76）高于对惰性NHL骨髓浸润的检出率15．38％（2／13,P〈0．06）。结论^18F-FDG PET／CT在诊断NHL骨髓浸润中有较高的应用价值。对局灶性骨髓浸润患者,PET／CT有助于引导BMB部位,提高骨髓浸润的检出率。PET／CT未检出骨髓浸润的惰性NHL患者,应进一步行BMB及FCM检查。推荐PET／CT、FCM及BMB三种方法联合应用判断NHL骨髓浸润,从而更准确地进行分期、治疗及判断预后。     

La tomographie par émission de positons au 18F-FDG en pathologie rénale non oncologique : indications actuelles et perspectives

Positron emission tomography combined with computed tomography (PET/CT) is a nuclear imaging technique which provides anatomical and functional information. PET/CT is increasingly used in non-oncological nephrology since conventional radiological approaches after injection of contrast agents are relatively contra-indicated in patients with chronic kidney disease (CKD). PET/CT after i.v. injection of ¹⁸F-fluoro-deoxy-glucose (FDG) is not toxic and is characterized by a high sensitivity. The level of irradiation (∼5 mSv) is acceptable. CKD does not significantly influence tissue uptake of ¹⁸F-FDG. The purpose of the present review aims at detailing the non-oncological indications of ¹⁸F-FDG PET/CT in general nephrology and after kidney transplantation. Particularly, ¹⁸F-FDG PET/CT appears useful in the diagnosis of cyst infection in patients with autosomal dominant polycystic kidney disease, as well as in the characterization of retroperitoneal fibrosis. In kidney transplant recipients, ¹⁸F-FDG PET/CT may help in the diagnostic work-up of suspected acute rejection, thereby eventually avoiding unnecessary kidney transplant biopsy. Perspectives in ¹⁸F-FDG PET/CT imaging are discussed, including innovative approaches of image analysis.     

Dual-Time <Superscript>18</Superscript>F-FDG PET/CT Imaging in Initial Locoregional Staging of Breast Carcinoma: Comparison with Conventional Imaging and Pathological Prognostic Factors

The aims of this retrospective study were to consider the diagnostic role of dual-time ¹⁸F-fluorodeoxyglucose positron emission tomography and computed tomography (¹⁸F-FDG PET/CT) in detection of breast carcinoma and axillary lymph node (ALN) status and to evaluate the primary tumor ¹⁸F-FDG uptake pattern. Preoperative staging was performed by ¹⁸F-FDG PET/CT in 78 female patients with breast carcinoma. Conventional imaging results were evaluated by breast magnetic resonance imaging (MRI) of 79 lesions in 78 patients, bilateral mammography (MMG) of 40 lesions in 40 patients, and breast ultrasonography (USG) of 47 lesions in 46 patients. The primary tumor detection rate using ¹⁸F-FDG PET/CT was higher than those using MRI, USG, and MMG. The sensitivity and specificity of ¹⁸F-FDG PET/CT scans for detecting multifocality were higher than those of MRI. The specificity of ALN metastasis detection with MRI was higher than that with ¹⁸F-FDG PET/CT, but ¹⁸F-FDG PET/CT had higher sensitivity. Higher ¹⁸F-FDG uptake levels were detected in patients with ALN metastasis, histologic grade 3, estrogen–progesterone-negative receptor status, lymphatic invasion, and moderate to poor prognostic groups. There was no statistical difference for the retention index in categorical pathological parameters except for progesterone-negative status. In conclusion, ¹⁸F-FDG PET/CT scans may be a valuable imaging technique for evaluating primary tumor and axillary status in staging breast carcinoma and ¹⁸F-FDG uptake may be a prognostic factor that indicates aggressive tumor biology and poor prognosis. Dual-time imaging in breast carcinoma staging may not be used for predicting pathological criteria and the aggressiveness of primary lesions.     

Diffusion-weighted MRI and PET/CT reproducibility in epithelial ovarian cancers during neoadjuvant chemotherapy

PurposeTo investigate the reproducibility of diffusion-weighted (DW) MRI and ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG)-Positron emission tomography/CT (PET/CT) in monitoring response to neoadjuvant chemotherapy in epithelial ovarian cancer.Materials and methodsTen women (median age, 67 years; range: 41.8–77.3 years) with stage IIIC-IV epithelial ovarian cancers were included in this prospective trial (NCT02792959) between 2014 and 2016. All underwent initial laparoscopic staging, four cycles of carboplatine-paclitaxel-based chemotherapy and interval debulking surgery. PET/CT and DW-MRI were performed at baseline (C0), after one cycle (C1) and before surgery (C4). Two nuclear physicians and two radiologists assessed five anatomic sites for the presence of ≥ 1 lesion. Target lesions in each site were defined and their apparent diffusion coefficient (ADC), maximal standardized uptake value (SUV-max), SUV-mean, SUL-peak, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were monitored (i.e., 10 patients × 5 sites × 3 time-points). Their relative early and late changes were calculated. Intra/inter-observer reproducibilities of qualitative and quantitative analysis were estimated with Kappa and intra-class correlation coefficients (ICCs).ResultsFor both modalities, inter- and intra-observer agreement percentages were excellent for initial staging but declined later for DW-MRI, leading to lower Kappa values for inter- and intra-observer variability (0.949 and 1 at C0, vs. 0.633 and 0.643 at C4, respectively) while Kappa values remained > 0.8 for PET/CT. Inter- and intra-observer ICCs were > 0.75 for SUV-max, SUL-peak, SUV-mean and their change regardless the time-point. ADC showed lower ICCs (range: 0.013–0.811). ANOVA found significant influences of the evaluation time, the measurement used (ADC, SUV-max, SUV-mean, SUV-max, SUL-peak, MTV or TLG) and their interaction on ICC values (P = 0.0023, P< 0.0001 and P =0.0028, respectively).ConclusionWhile both modalities demonstrated high reproducibility at baseline, only SUV-max, SUL-peak, SUV-mean and their changes maintained high reproducibility during chemotherapy.     

Characteristics of Primary Papillary Thyroid Carcinoma with False-Negative Findings on Initial 18F-FDG PET/CT

Background

We often observe that uptake of tracer is not detected in the primary cancer focus in patients with histologically proven papillary thyroid carcinoma (PTC) on preoperative ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT). Therefore, we analyzed the clinical and pathologic variables affecting false-negative findings in primary tumors on preoperative ¹⁸F-FDG PET/CT.

Methods

We retrospectively reviewed the medical records of 115 consecutive patients who underwent ¹⁸F-FDG PET/CT for initial evaluation and were diagnosed with PTC by postoperative permanent biopsy. The clinical and pathologic characteristics that influence the ¹⁸F-FDG PET/CT findings in these patients were analyzed with respect to the following variables: age, gender, tumor size, multifocality of the primary tumor, perithyroidal invasion, lymphovascular or capsular invasion, and central lymph node metastasis-based final pathology.

Results

Twenty-six (22.6%) patients had false-negative ¹⁸F-FDG PET/CT findings. In patients with negative ¹⁸F-FDG PET/CT findings, tumor size, and perithyroidal and lymphovascular invasion were significantly less than in patients with positive ¹⁸F-FDG PET/CT findings. Tumors >1 cm in size were correlated with ¹⁸F-FDG PET/CT positivity. On multivariate analysis, perithyroidal invasion (P = 0.026, odds ratio = 7.714) and lymphovascular invasion (P = 0.036, odds ratio = 3.500) were independent factors for ¹⁸F-FDG PET/CT positivity. However, there were no significant differences between ¹⁸F-FDG PET/CT positivity and age, gender, capsular invasion, and central lymph node metastasis based on final pathology.

Conclusions

Tumor size and perithyroidal and lymphovascular invasion of papillary carcinoma can influence ¹⁸F-FDG PET/CT findings. Absence of perithyroidal and lymphovascular invasion were independent variables for false-negative findings on initial ¹⁸F-FDG PET/CT in patients with PTC.     

Clinical value of 18FDG PET/MRI in muscle-invasive,locally advanced,and metastatic bladder cancer

ObjectiveMetastatic bladder cancer is an aggressive disease that can often be difficult to diagnose and stage with conventional cross-sectional imaging. The primary objective of this study was to determine the clinical value of fluorine-18 2-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) PET/MRI for surveillance and restaging of patients with muscle-invasive, locally advanced, and metastatic bladder cancer compared to conventional imaging methods.Materials and MethodsThis retrospective study enrolled patients with muscle-invasive, locally advanced and metastatic bladder cancer in a single institute evaluated with ¹⁸F-FDG PET/MRI. All patients also underwent conventional imaging with CT. Additional imaging may also have included ¹⁸F-FDG PET/CT (¹⁸F-FDG PET), or sodium fluoride (NaF) PET/CT in some patients. Images were reviewed by a diagnostic radiologist/nuclear medicine physician. Number of lesions and sites of disease were captured and compared between ¹⁸F-FDG PET/MRI and conventional imaging. Lesions were confirmed by sequential imaging or lesion biopsy. All patients were followed for survival.ResultsFifteen patients (4 for surveillance; 11 for restaging) underwent 34 ¹⁸F-FDG PET/MRI scans. Each patient received a corresponding conventional CT around the time of the ¹⁸F-FDG PET/MRI (median 6 days). The 15 patients (11 male; 4 female) had a median age of 61.5 years (range 37–73) and histologies of urothelial carcinoma (n = 13) and small-cell carcinoma of the bladder (n = 2) diagnosed as stage 4 (n = 13), stage 3 (n = 1), or stage 2 (n = 1). ¹⁸F-FDG PET/MRI detected 82 metastatic malignant lesions involving lymph nodes (n = 22), liver (n = 10), lung (n = 34), soft tissue (n = 12), adrenal glands (n = 1), prostate (n = 1), and bone (n = 2) with a resultant advantage of 36% for lesion visibility in comparison with CT. Serial imaging or biopsy confirmed these lesions as malignant.Conclusion¹⁸F-FDG PET/MRI can detect metastatic lesions which cannot be identified on conventional CT, and this can allow for better treatment planning and improved disease monitoring during therapy.     

Clinical and Pathological Factors Related to 18F-FDG-PET Positivity in the Diagnosis of Recurrence and/or Metastasis in Patients with Differentiated Thyroid Cancer

Background  Objectives were to analyze the relationship between a positive ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) result and clinical and tumor factors in patients treated for differentiated thyroid cancer (DTC) and under suspicion of recurrence or metastasis, and to determine the diagnostic validity of PET in DTC patients with elevated serum thyroglobulin (Tg) and negative ¹³¹I whole-body scan (¹³¹I-WBS). Methods  We studied 50 DTC patients with elevated serum Tg and negative WBS treated with total thyroidectomy and ¹³¹I ablation. Thyroxin treatment was withdrawn and patients were on iodine-free diet before WBS. Tg, anti-Tg antibodies, and thyroid-stimulating hormone (TSH) were determined. Patients with negative WBS and elevated Tg underwent PET study 1 week later. PET findings were verified by pathology findings or other imaging techniques [computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US)] and/or 12-month follow-up. The relationship between PET findings and tumor (histological type, size, multifocality, thyroid capsular invasion, lymph-node and/or metastatic involvement) and clinical (age at diagnosis, sex, Tg, accumulated iodine dose, and recurrence time) variables was analyzed. Results  PET was positive in 32/39 patients with confirmed disease (82% sensitivity) and negative in 7/11 of disease-free cases (64% specificity), a positive predictive value (PPV) of 89%. Tumor size (P < 0.05) and thyroid capsular invasion (P < 0.05) were significantly associated with positive PET study. The relationship of PET findings with Tg levels and age at diagnosis was close to significance. Conclusion   ¹⁸F-FDG-PET study offers a high sensitivity and positive predictive value (PPV) in patients with negative WBS and Tg positive. The use of FDG-PET is strongly recommended in DTC patients with large tumors, thyroid capsule invasion or poor-prognosis variants.     

Utility of ¹⁸F-FDG PET/CT in identifying penile squamous cell carcinoma metastatic lymph nodes

ObjectivesDue to the significant potential morbidity of inguinal and pelvic lymphadenectomy, the search for an imaging modality that can accurately identify penile squamous cell carcinoma (SCCA) lymphatic metastases continues. Initial ¹⁸F-FDG PET/CT studies have reported 80% sensitivity and 100% specificity in the detection of inguinal and obturator lymph node metastasis. We review a single institutional experience of ¹⁸F-FDG PET/CT imaging of SCCA of the penis to assess for accuracy and potential impact on clinical management.MethodsThree patients diagnosed with penile SCCA at a single institution underwent staging ¹⁸F-FDG PET/CT and went on to subsequent inguinal lymph node dissection. The ¹⁸F-FDG PET machine was a Philips Gemini Time-of-Flight PET with LYSO crystals with 4.7 mm spatial resolution. The CT was a 16-slice helical CT with 5 mm slice widths. ¹⁸F-FDG PET/CT findings were compared with the histologic findings of these procedures. Decision to proceed with lymphadenectomy was based on clinical judgment of a single urologist and all fused ¹⁸F-FDG PET/CT imaging was assessed by a single experienced radiologist.ResultsNo patient received chemotherapy or radiation before the ¹⁸F-FDG PET/CT or surgery. The first patient was obese (BMI > 30), clinically node negative, and the ¹⁸F-FDG PET/CT showed inflammation. Histologic examination showed a positive 2 cm right inguinal metastatic node. The second patient's ¹⁸F-FDG PET/CT showed a suspicious 1 cm left inguinal node. Histologically, the suspicious lymph node was positive for SCCA as was a second positive 2 cm lymph node not identified on preoperative ¹⁸F-FDG PET/CT. Clinical exam of this patient was negative. The third patient was ¹⁸F-FDG PET/CT and clinically negative but subsequently developed a palpable lymph node approximately 1 month later, which was suspicious on repeat ¹⁸F-FDG PET/CT and positive for SCCA on histological examination.Conclusions¹⁸F-FDG PET/CT has shown initial promise in the staging of penile SCCA. However, our review shows that false negative studies occur at alarmingly high rates, and ¹⁸F-FDG PET/CT is poor in detection of micro-metastasis. Thus, close follow-up in these patients is imperative.     

Imaging of multiple myeloma: Current concepts

Medical imaging is of crucial importance for diagnosis and initial staging as well as for differentiation of multiple myeloma (MM) from other monoclonal plasma cell diseases. Conventional radiography represents the reference standard for diagnosis of MM due to its wide availability and low costs despite its known limitations such as low sensitivity, limited specificity and its inability to detect extraosseous lesions. Besides conventional radiography, newer cross-sectional imaging modalities such as whole-body low-dose computed tomography (CT), whole-body magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT are available for the diagnosis of osseous and extraosseous manifestations of MM. Whole-body low-dose CT is used increasingly, replacing conventional radiography at selected centers, due to its higher sensitivity for the detection of osseous lesions and its ability to diagnose extraosseous lesions. The highest sensitivity for both detection of bone marrow disease and extraosseous lesions can be achieved with whole-body MRI and ¹⁸F-FDG PET/CT. According to current evidence, MRI is the most sensitive method for initial staging while ¹⁸F-FDG PET/CT allows monitoring of treatment of MM. There is an evolving role for assessment of treatment response using newer MR imaging techniques. Future studies are needed to further define the exact role of the different imaging modalities for individual risk stratification and therapy monitoring.     

Performance characteristics of 18F-fluciclovine positron emission tomography/computed tomography prior to retroperitoneal lymph node dissection

IntroductionWe aimed to determine whether anti-1-amino-3-¹⁸F-fluorocyclobutane-1-carboxylic acid (¹⁸F-fluciclovine) positron emission tomography/computed tomography (PET/CT) can accurately detect residual non-seminomatous germ cell tumor (NSGCT) prior to retroperitoneal lymph node dissection (RPLND). There is no reliable way to differentiate between fibrosis/necrosis, teratoma, and viable germ cell tumor in patients receiving post-chemotherapy RPLND. Functional imaging, including ¹⁸F-fludeoxyglucose (18F-FDG) PET/CT, has been disappointing. Due to the need for better imaging modalities, our prospective, pilot study aims to investigate the accuracy of ¹⁸F-fluciclovine PET/CT in detecting residual tumor prior to RPLND.MethodsFrom March 2018 to May 2019, 10 eligible patients underwent preoperative ¹⁸F-fluciclovine PET/CT prior to undergoing bilateral, full-template RPLND or excision of mass (for one re-do RPLND) in a prospective, phase 2 study. Correlation between ¹⁸F-fluciclovine PET/CT and RPLND pathology were evaluated on a per-patient level.ResultsA total of 10 patients (mean age 29±7.6 years) underwent ¹⁸F-fluciclovine PET/CT prior to surgery. Nine of 10 patients received chemotherapy prior to RPLND. Correlation between ¹⁸F-fluciclovine PET/CT and RPLND pathology was seen in 3/10 (30%) patients. Five of 10 patients (50%) with negative ¹⁸F-fluciclovine PET/CT were found to have residual disease/teratoma on RPLND. Compared to the reference standard of RPLND, ¹⁸F-fluciclovine PET/CT demonstrated 29% sensitivity and 33% specificity. No patients experienced any adverse events due to ¹⁸F-fluciclovine PET/CT.ConclusionsDespite a different mechanism of action from ¹⁸F-FDG, ¹⁸F-fluciclovine has low sensitivity and specificity for residual teratoma in the retroperitoneum.     

18F-FDG Uptake at Initial Staging of the Adrenocortical Cancers: A Diagnostic Tool but Not of Prognostic Value

Background

Adrenocortical carcinoma (ACC) is a rare cancer for which little level evidence exists to guide management. ¹⁸F-FDG PET (¹⁸F-fluorodeoxyglucose positron emission tomography) is an increasingly used diagnostic tool in patients with suspicious or indeterminate adrenal tumors. In some other solid tumors, ¹⁸F-FDG PET may offer prognostic information that can guide optimal patient treatment. The aim of the present study was to evaluate whether preoperative ¹⁸F-FDG PET based on SUVs assessments has a prognostic value in ACC patients.

Methods

A retrospective analysis was performed in patients who underwent ¹⁸F-FDG PET/CT for the evaluation of ACC. Inclusion criteria were an unequivocal diagnosis of ACC; all data from primary diagnosis available; ¹⁸F-FDG PET/CT performed prior to surgery or other treatment of the primary tumor; a minimum of 6-months follow-up for surviving patients. All ¹⁸F-FDG PET/CT procedures were reinterpreted in a blind fashion.

Results

Thirty-seven patients (23 without metastasis [M0], 14 with metastasis [M1]) fulfilled the study criteria. Median uptake values were tumor standardized uptake values (SUV)_max = 11 (range: 3–56) and a tumor/liver SUV_max ratio = 4.2 (range: 1.3–15). Median follow-up was 20 months. Although classic risk factors (tumoral stage, Weiss score) were associated with poor outcome, there was no correlation between primary tumor FDG uptake with overall survival (OS) and disease free survival (DFS) in M0 patients and with overall survival in M1 patients. ¹⁸F-FDG uptake correlated inconsistently with sinister histological features, such as atypical mitoses or necrosis.

Conclusions

At initial staging, primary tumor FDG uptake in ACC patients does not correlate with OS and DFS at 2 years. Patient prognosis and treatment strategy should not be based on uptake values.     

Utility of 18F-FDG PET/CT for Detecting Neck Metastasis in Patients with Salivary Gland Carcinomas: Preoperative Planning for Necessity and Extent of Neck Dissection

Background:

The precise diagnosis of cervical lymph node metastasis (CLNM) of salivary gland cancer is important to determine the surgical extent and adjuvant therapy. This study assessed the clinical utility of ¹⁸F-FDG PET in identifying CLNM in such patients.

Methods:

Fifty-four patients with intermediate or high-grade salivary gland cancer were preoperatively evaluated with ¹⁸F-FDG PET/CT and CT/MRI. Histopathologic analysis of neck dissection tissues was used as the gold standard for assessing imaging techniques. Tumor and nodal maximum standardized uptake values (SUVmax) were measured for each patient. Univariate and multivariate analyses were used to identify CLNM predictive factors.

Results:

Of the 54 patients, 24 patients (44 %) had CLNM. On a per-patient basis, the sensitivity and specificity of ¹⁸F-FDG PET/CT and CT/MRI were not significantly different (92 vs. 83 %, P = 0.625 and 93 vs. 97 %, P = 1.000, respectively). On a per-level basis, ¹⁸F-FDG PET/CT was significantly more sensitive and accurate than CT/MRI in the ipsilateral neck (96 vs. 54 %, P < 0.001 and 92 vs. 83 %, P < 0.001, respectively). The mean nodal SUVmax values of patients with and without nodal metastasis were 4.9 and 2.1, respectively (P = 0.008). Histologic grade was a significant predictor of CLNM (P = 0.014, odds ratio 14.46, 95 % confidence interval 1.73–120.79).

Conclusions:

¹⁸F-FDG PET/CT imaging and histologic grade are useful for detecting CLNM in patients with salivary gland carcinoma. This finding may guide preoperative planning for the necessity and extent of neck dissection in these patients.     

Pulmonary epithelioid hemangioendothelioma

We report two cases of pulmonary epithelioid hemangioendothelioma (PEH). Both patients presented with multiple bilateral pulmonary nodules, <10 mm diameter, on computed tomography (CT). Multiple pulmonary metastases were considered, but no primary malignant lesion was detected by other imaging modalities including ¹⁸F-fl uorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET)/CT. Moreover, the nodules did not show increased uptake of ¹⁸F-FDG. We performed pulmonary wedge resections by video-assisted thoracoscopic surgery (VATS). Histological and immunohistochemical analysis revealed PEH in both. Positivity for the monoclonal antibody MIB-1 in the tumor cells was 5% in the fi rst case and 5%–10% in the second case. Slow tumor progression was detected with CT in the second case. Although ¹⁸F-FDG PET/CT is effective for screening other malignant lesions, it does not appear to be of direct use in the diagnosis and surgical planning of PEH. Pathological diagnosis by VATS is the most effective method. MIB-1 positivity should be analyzed as to whether it is a prognostic factor of PEH.     

18F-FDG PET/CT在胆道系统恶性肿瘤中的应用

目的探讨~(18)F-FDG PET/CT诊断胆道系统恶性肿瘤的价值。方法回顾性分析34例临床疑似胆道恶性肿瘤患者的PET/CT影像资料,均获得术后病理结果,其中12例经手术切除淋巴结或淋巴结穿刺活检对18枚淋巴结获得病理诊断;与病理结果对照,计算PET/CT对胆道恶性病变原发灶、淋巴结转移的灵敏度、特异度、阳性预测值、阴性预测值及准确率。结果 34例中,31例为恶性病变,3例为良性病变。PET/CT诊断胆道恶性肿瘤原发灶的灵敏度100%(31/31),特异度66.67%(2/3),阳性预测值96.88%(31/32),阴性预测值100%(2/2),准确率97.06%(33/34)。胆道恶性病变原发灶最大标准摄取值(SUV_(max))为8.42±4.27;3例胆道良性疾病SUV_(max)分别为12.90、2.00及1.90。共18枚淋巴结获得病理结果,包括转移性淋巴结13枚,良性增生5枚。PET/CT诊断淋巴结转移的灵敏度76.92%(10/13),特异度60.00%(3/5),阳性预测值83.33%(10/12),阴性预测值50.00%(3/6),准确率72.22%(13/18)。结论 PET/CT对胆道系统恶性肿瘤的诊断具有重要价值。     

Radioactive Iodine Remnant Uptake After Completion Thyroidectomy: Not Such a Complete Cancer Operation

Background

Given limitations in preoperative diagnostics, thyroid lobectomy followed by completion thyroidectomy (CT) for differentiated thyroid cancer (DTC) may be required. It is unclear whether resection quality by CT differs from that by total thyroidectomy (TT). Additional surgeon or patient factors may also influence the “completeness” of resection. This study evaluated how CT and surgeon volume influence the adequacy of resection as measured by radioactive iodine (RAI) remnant uptake.

Methods

A retrospective review of a prospectively collected thyroid database was queried for patients treated for DTC with TT or CT followed by RAI ablation. CT patients were matched 1:2 by age, sex, and tumor size to TT patients. Surgeon volume, time to completion, and continuity of surgeon care were reviewed.

Results

Over 18 years, 45 patients with DTC had CT and RAI. Mean age was 48 ± 2 years, and 76 % were female, with a tumor size of 2.7 ± 0.3 cm. CT had higher remnant uptake than TT (0.07 vs. 0.04 %; p = 0.04). CT performed by a high-volume surgeon had much lower remnant uptakes (0.06 vs. 0.22 %; p = 0.04). Remnant uptake followed a stepwise decrease with involvement of a high-volume surgeon for part or all of the surgical management (p = 0.11). Multiple regression analysis found CT (p = 0.02) and surgeon volume (p = 0.04) to significantly influence uptake after controlling for other factors.

Conclusions

Single-stage TT provides a better resection based on smaller thyroid remnant uptakes than CT for patients with thyroid cancer. If a staged operation for cancer is necessary, surgeon volume may affect the completeness of resection.     

What Is the Comparative Ability of 18F-FDG PET/CT, 99mTc-MDP Skeletal Scintigraphy,and Whole-body MRI as a Staging Investigation to Detect Skeletal Metastases in Patients with Osteosarcoma and Ewing Sarcoma?

BackgroundSkeletal metastases of bone sarcomas are indicators of poor prognosis. Various imaging modalities are available for their identification, which include bone scan, positron emission tomography/CT scan, MRI, and bone marrow aspiration/biopsy. However, there is considerable ambiguity regarding the best imaging modality to detect skeletal metastases. To date, we are not sure which of these investigations is best for screening of skeletal metastasis.Question/purposeWhich staging investigation—¹⁸F-fluorodeoxyglucose positron emission tomography/CT (¹⁸F-FDG PET/CT), whole-body MRI, or ^99mTc-MDP skeletal scintigraphy—is best in terms of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in detecting skeletal metastases in patients with osteosarcoma and those with Ewing sarcoma?MethodsA prospective diagnostic study was performed among 54 of a total 66 consecutive osteosarcoma and Ewing sarcoma patients who presented between March 2018 and June 2019. The institutional review board approved the use of all three imaging modalities on each patient recruited for the study. Informed consent was obtained after thoroughly explaining the study to the patient or the patient’s parent/guardian. The patients were aged between 4 and 37 years, and their diagnoses were proven by histopathology. All patients underwent ^99mTc-MDP skeletal scintigraphy, ¹⁸F-FDG PET/CT, and whole-body MRI for the initial staging of skeletal metastases. The number and location of bone and bone marrow lesions diagnosed with each imaging modality were determined and compared with each other. Multidisciplinary team meetings were held to reach a consensus about the total number of metastases present in each patient, and this was considered the gold standard. The sensitivity, specificity, PPV, and NPV of each imaging modality, along with their 95% confidence intervals, were generated by the software Stata SE v 15.1. Six of 24 patients in the osteosarcoma group had skeletal metastases, as did 8 of 30 patients in the Ewing sarcoma group. The median (range) follow-up for the study was 17 months (12 to 27 months). Although seven patients died before completing the minimum follow-up, no patients who survived were lost to follow-up.ResultsWith the number of patients available, we found no differences in terms of sensitivity, specificity, PPV, and NPV among the three staging investigations in patients with osteosarcoma and in patients with Ewing sarcoma. Sensitivities to detect bone metastases for ¹⁸F-FDG PET/CT, whole-body MRI, and ^99mTc-MDP skeletal scintigraphy were 100% (6 of 6 [95% CI 54% to 100%]), 83% (5 of 6 [95% CI 36% to 100%]), and 67% (4 of 6 [95% CI 22% to 96%]) and specificities were 100% (18 of 18 [95% CI 82% to 100%]), 94% (17 of 18 [95% CI 73% to 100%]), and 78% (14 of 18 [95% CI 52% to 94%]), respectively, in patients with osteosarcoma. In patients with Ewing sarcoma, sensitivities to detect bone metastases for ¹⁸F-FDG PET/CT, whole-body MRI, and ^99mTc-MDP skeletal scintigraphy were 88% (7 of 8 [95% CI 47% to 100%]), 88% (7 of 8 [95% CI 47% to 100%]), and 50% (4 of 8 [95% CI 16% to 84%]) and specificities were 100% (22 of 22 [95% CI 85% to 100%]), 95% (21 of 22 [95% CI 77% to 100%]), and 95% (21 of 22 [95% CI 77% to 100%]), respectively. Further, the PPVs for detecting bone metastases for ¹⁸F-FDG PET/CT, whole-body MRI, and ^99mTc-MDP skeletal scintigraphy were 100% (6 of 6 [95% CI 54% to 100%]), 83% (5 of 6 [95% CI 36% to 100%]), and 50% (4 of 8 [95% CI 16% to 84%]) and the NPVs were 100% (18 of 18 [95% CI 82% to 100%]), 94% (17 of 18 [95% CI 73% to 100%]), and 88% (14 of 16 [95% CI 62% to 98%]), respectively, in patients with osteosarcoma. Similarly, the PPVs for detecting bone metastases for ¹⁸F-FDG PET/CT, whole-body MRI, and ^99mTc-MDP skeletal scintigraphy were 100% (7 of 7 [95% CI 59% to 100%]), 88% (7 of 8 [95% CI 50% to 98%]), and 80% (4 of 5 [95% CI 28% to 100%]), and the NPVs were 96% (22 of 23 [95% CI 78% to 100%]), 95% (21 of 22 [95% CI 77% to 99%]), and 84% (21 of 25 [95% CI 64% to 96%]), respectively, in patients with Ewing sarcoma. The confidence intervals around these values overlapped with each other, thus indicating no difference between them.ConclusionBased on these results, we could not demonstrate a difference in the sensitivity, specificity, PPV, and NPV between ¹⁸F-FDG PET/CT, whole-body MRI, and ^99mTc-MDP skeletal scintigraphy for detecting skeletal metastases in patients with osteosarcoma and Ewing sarcoma. For proper prognostication, a thorough metastatic workup is essential, which should include a highly sensitive investigation tool to detect skeletal metastases. However, our study findings suggest that there is no difference between these three imaging tools. Since this is a small group of patients in whom it is difficult to make broad recommendations, these findings may be confirmed by larger studies in the future.Level of EvidenceLevel II, diagnostic study.     

18F-FDGPET/CT在非小细胞肺癌早期化疗疗效评价中的应用

18F-FDG PET/CT是一种从细胞分子水平反映肿瘤组织生化和代谢变化的功能显像方法,其监测肿瘤治疗疗效的原理是基于肿瘤细胞在化疗后对葡萄糖代谢的变化。近年来,越来越多的研究致力于18 F-FDG PET/CT在评价非小细胞肺癌化疗疗效方面的作用。本文就18F-FDG PET/CT在非小细胞肺癌早期化疗疗效评价中的应用价值进行综述。     

Incidental focal colonic lesions found on 18Fluorodeoxyglucose positron emission tomography/computed tomography scan: further support for a national guideline on definitive management

Aim ¹⁸Fluorodeoxyglucose (¹⁸FDG) positron emission tomography/computed tomography (PET/CT) is an established part of staging in a wide variety of malignancies. Incidental abnormal uptake of ¹⁸FDG of unknown significance is frequently encountered. Therefore, we investigated patients with abnormal colonic uptake of ¹⁸FDG, determined by PET/CT images, using colonoscopy. Method The radiology reports of all patients referred to a tertiary referral centre for a PET/CT scan were reviewed retrospectively. Patients with abnormal colonic uptake of ¹⁸FDG were identified and the PET/CT findings were correlated with colonoscopic findings. Results Of 555 consecutive patients identified over a 26‐month period, 53 had abnormal colonic uptake of ¹⁸FDG, as determined by PET/CT images. Twenty‐nine were not investigated following discussion in a specialist multidisciplinary (MDT) meeting, according to local protocol. Twenty out of 24 patients investigated by endoscopy had a colonic lesion correlating to the site identified on the PET/CT image: 16 patients had tubulovillous adenomas (nine of which were > 10 mm), two had invasive adenocarcinomas, two had diverticular disease and one had collagenous colitis; no colonic lesion was detected in three. These findings were incidental and not related to the primary diagnosis for which the scan was being performed. Accordingly, a positive predictive value of 83% is associated with the finding of abnormal uptake of ¹⁸FDG on PET/CT images. Conclusion Incidental abnormal colonic uptake of ¹⁸FDG, determined by a PET/CT scan requires definitive colonic investigation in patients suitable for further treatment because significant colonic pathology is frequently identified. The benefit of this approach should be discussed in specialist MDT meetings and tailored to each patient; however, national guidelines for management are required.     

Cardiac functional imaging

During the last 20 years, cardiac imaging has drastically evolved. Positron emission tomography (PET), fast three-dimensional (3D) imaging with the latest generations of echocardiography & multi-detector computed tomography (CT), stress perfusion assessed by magnetic resonance imaging (MRI), blood flow analysis using four-dimensional (4D) flow MRI, all these techniques offer new trends for optimal noninvasive functional cardiac imaging. Dynamic functional imaging is obtained by acquiring images of the heart at different phases of the cardiac cycle, allowing assessment of cardiac motion, function, and perfusion. Between CT and Cardiac MRI (CMR), CMR has the best temporal resolution, which is suitable for functional imaging while cardiac CT provides higher spatial resolution with isotropic data that have an identical resolution in the three dimensions of the space. The latest generations of CT scanners enable whole heart assessment in one beat, offering also an acceptable temporal resolution with the possibility to display the images in a dynamic mode. Another rapidly growing technique using functional and molecular imaging for the assessment of biological and metabolic pathways is the PET using radio-labeled tracers. Meanwhile, the oldest cardiac imaging tool with doppler ultrasound technology has never stopped evolving. Echocardiography today performs 3D imaging, stress perfusion, and myocardial strain assessment, with high temporal resolution. It still is the first line and more accessible exam for the patient. These different modalities are complementary and may be even combined into PET-CT or PET-MRI. The ability to combine the functional/molecular data with anatomical images may implement a new dimension to our diagnostic tools.