Oscillating Gradient Diffusion-Weighted MRI for Risk Stratification of Uterine Endometrial Cancer.

BACKGROUND: Oscillating gradient diffusion-weighted imaging (DWI) enables elucidation of microstructural characteristics in cancers; however, there are limited data to evaluate its utility in patients with endometrial cancer. PURPOSE: To investigate the utility of oscillating gradient DWI for risk stratification in patients with uterine endometrial cancer compared with conventional pulsed gradient DWI. STUDY TYPE: Retrospective. SUBJECTS: Sixty-three women (mean age: 58 [range: 32-85] years) with endometrial cancer. FIELD STRENGTH/SEQUENCE: 3 T MRI including DWI using oscillating gradient spin-echo (OGSE) and pulsed gradient spin-echo (PGSE) research sequences. ASSESSMENT: Mean value of the apparent diffusion coefficient (ADC) values for OGSE (ADCOGSE ) and PGSE (ADCPGSE ) as well as the ADC ratio (ADCOGSE /ADCPGSE ) within endometrial cancer were measured using regions of interest. Prognostic factors (histological grade, deep myometrial invasion, lymphovascular invasion, International Federation of Gynecology and Obstetrics [FIGO] stage, and prognostic risk classification) were tabulated. STATISTICAL TESTS: Interobserver agreement was analyzed by calculating the intraclass correlation coefficient. The associations of ADCOGSE , ADCPGSE , and ADCOGSE /ADCPGSE with prognostic factors were examined using the Kendall rank correlation coefficient, Mann-Whitney U test, and receiver operating characteristic (ROC) curve. A P value of <0.05 was statistically significant. RESULTS: Compared with ADCOGSE and ADCPGSE , ADCOGSE /ADCPGSE was significantly and strongly correlated with histological grade (observer 1, τ = 0.563; observer 2, τ = 0.456), FIGO stage (observer 1, τ = 0.354; observer 2, τ = 0.324), and prognostic risk classification (observer 1, τ = 0.456; observer 2, τ = 0.385). The area under the ROC curves of ADCOGSE /ADCPGSE for histological grade (observer 1, 0.92, 95% confidence intervals [CIs]: 0.83-0.98; observer 2, 0.84, 95% CI: 0.73-0.92) and prognostic risk (observer 1, 0.80, 95% CI: 0.68-0.89; observer 2, 0.76, 95% CI: 0.63-0.86) were significantly higher than that of ADCOGSE and ADCPGSE . DATA CONCLUSION: The ADC ratio obtained via oscillating gradient and pulsed gradient DWIs might be useful imaging biomarkers for risk stratification in patients with endometrial cancer. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 2.

Dual-Energy CT-Derived Electron Density for Diagnosing Metastatic Mediastinal Lymph Nodes in Non-Small Cell Lung Cancer: Comparison With Conventional CT and FDG PET/CT Findings.

BACKGROUND. Accurate nodal staging is essential to guide treatment selection in patients with non-small cell lung cancer (NSCLC). To our knowledge, measurement of electron density (ED) using dual-energy CT (DECT) is unexplored for this purpose. OBJECTIVE. The purpose of our study was to assess the utility of ED from DECT in diagnosing metastatic mediastinal lymph nodes in patients with NSCLC in comparison with conventional CT and FDG PET/CT. METHODS. This retrospective study included 57 patients (36 men, 21 women; mean age, 68.4 ± 8.9 [SD] years) with NSCLC and surgically resected mediastinal lymph nodes who underwent preoperative DECT and FDG PET/CT. The patients had a total of 117 resected mediastinal lymph nodes (33 metastatic, 84 nonmetastatic). Two radiologists independently reviewed the morphologic features of nodes on the 120-kVp images and also measured the iodine concentration (IC) and ED of nodes using maps generated from DECT data; consensus was reached for discrepancies. Two different radiologists assessed FDG PET/CT examinations in consensus for positive node uptake. Diagnostic performance was evaluated for individual and pairwise combinations of features. RESULTS. The sensitivity, specificity, and accuracy for nodal metastasis were 15.2%, 98.8%, and 75.2% for the presence of necrosis, respectively; 54.5%, 85.7%, and 76.9% for short-axis diameter greater than 8.5 mm; 63.6%, 73.8%, and 70.9% for long-axis diameter greater than 13.0 mm; 51.5%, 79.8%, and 71.8% for attenuation on 120-kVp images of 95.8 HU or less; 87.9%, 58.3%, and 66.7% for ED of 3.48 × 1023/cm3 or less; and 66.7%, 75.0%, and 72.6% for positive FDG uptake. Among pairwise combinations of features, accuracy was highest for the combination of ED and short-axis diameter (accuracy, 82.9%; sensitivity, 54.5%; specificity, 94.0%) and the combination of ED and positive FDG uptake (accuracy, 82.1%; sensitivity, 60.6%; specificity, 90.5%); these accuracies were greater than those for the individual features (p < .05). The remaining combinations exhibited accuracies ranging from 74.4% to 77.8%. Interobserver agreement analysis showed an intraclass correlation coefficient of 0.90 for ED. IC was not significantly different between metastatic and nonmetastatic nodes (p = .18) and was excluded from the diagnostic performance analysis. CONCLUSION. ED derived from DECT may help diagnose metastatic lymph nodes in NSCLC given decreased ED in metastatic nodes. CLINICAL IMPACT. ED may complement conventional CT findings and FDG uptake on PET/CT in diagnosing metastatic nodes.

Predicting tumor response and prognosis to neoadjuvant chemotherapy in esophageal squamous cell carcinoma patients using PERCIST: a multicenter study in Japan.

PURPOSE: To investigate the usefulness of the positron emission tomography response criteria in solid tumors 1.0 (PERCIST1.0) for predicting tumor response to neoadjuvant chemotherapy and prognosis and determine whether PERCIST improvements are necessary for esophageal squamous cell carcinoma (ESCC) patients. PATIENTS AND METHODS: We analyzed the cases of 177 ESCC patients and examined the association between PERCIST and their pathological responses. Associations of whole-PERCIST with progression-free survival (PFS) and overall survival (OS) were evaluated by a Kaplan-Meier analysis and Cox proportional hazards model. To investigate potential PERCIST improvements, we used the survival tree technique to understand patients' prognoses. RESULTS: There were significant correlations between the pathologic response and PERCIST of primary tumor (p < 0.001). The optimal cutoff value of the primary tumors' SULpeak response to classify pathologic responses was -50.0%. The diagnostic accuracy of SULpeak response was 87.3% sensitivity, 54.1% specificity, 68.9% accuracy, positive predictive value 60.5%, and negative predictive value 84.1%. Whole-PERCIST was significantly associated with PFS and OS. The survival tree results indicated that a high reduction of the whole SULpeak response was significantly correlated with the patients' prognoses. The cutoff values for the separation of prognoses were - 52.5 for PFS and - 47.1% for OS. CONCLUSION: PERCIST1.0 can help predict tumor responses and prognoses. However, 18F-FDG-PET/CT tends to underestimate residual tumors in histopathological response evaluations. Modified PERCIST, in which the partial metabolic response is further classified by the SULpeak response (-50%), might be more appropriate than PERCIST1.0 for evaluating tumor responses and stratifying high-risk patients for recurrence and poor prognosis.

The clinical value of texture analysis of dual-time-point 18F-FDG-PET/CT imaging to differentiate between 18F-FDG-avid benign and malignant pulmonary lesions.

OBJECTIVES: To examine whether the texture analysis of dual-time-point (DTP) F-18-fluorodeoxyglucose (18F-FDG)-PET/CT imaging can differentiate between 18F-FDG-avid benign and malignant pulmonary lesions. METHODS: We compared standardized uptake value (SUV)-related (SUVmax [g/ml] and SUVmean [g/ml]), volumetric (metabolic tumor volume [MTV] [cm3] and total lesion glycolysis [TLG] [g]), and texture (entropy, homogeneity, dissimilarity, intensity variability [IV], size-zone variability [SZV], and zone percentage [ZP]) (MTV ≥ 5.0 cm3 and SUV ≥ 2.5 g/ml) parameters between 13 benign and 46 malignant lesions using the Mann-Whitney U test. Diagnostic performance was evaluated by receiver operating characteristic (ROC) analysis. Stepwise logistic regression analysis was performed to identify and use the independent variables that correctly differentiate between benign and malignant lesions. RESULTS: Malignant pulmonary lesions showed significantly higher SUVmax, SUVmean, MTV, TLG, entropy, dissimilarity, IV, and SZV and significantly lower homogeneity and ZP than benign pulmonary lesions (all p < 0.05) in both early and delayed images. Their areas under the ROC curves (AUCs) ranged between 0.69 and 0.94, and diagnostic accuracies between 64.4% and 93.2%. Entropy-early (p = 0.014), SUVmean-delay (p = 0.039), and dissimilarity-delay (p = 0.027) were independent parameters, and combined use of them yielded the highest AUC (0.98) with 100% sensitivity (46/46), 84.6% specificity (11/13), and 96.7% (57/59) accuracy for distinguishing between benign and malignant lesions. CONCLUSIONS: The individual early and delayed SUV-related, volumetric, and texture parameters showed a wide range of accuracy. Combined use of independent parameters extracted from DTP imaging might yield a high diagnostic accuracy with balanced sensitivity and specificity to differentiate between benign and malignant 18F-FDG-avid pulmonary lesions. KEY POINTS: • Malignant pulmonary lesions showed significantly higher SUV-related (SUVmax and SUVmean) and volumetric (MTV and TLG) parameters than benign pulmonary lesions in both early and delayed images. • Malignant pulmonary lesions showed significantly more heterogeneous18F-FDG uptake than benign pulmonary lesions in both early and delayed images. • Combined use of independent parameters extracted from DTP imaging might yield a high diagnostic accuracy to differentiate between benign and malignant18F-FDG-avid pulmonary lesions.

Extracellular volume fraction determined by equilibrium contrast-enhanced dual-energy CT as a prognostic factor in patients with stage IV pancreatic ductal adenocarcinoma.

OBJECTIVES: To evaluate the feasibility of equilibrium contrast-enhanced dual-energy CT (DECT), as compared with single-energy CT (SECT) and to calculate extracellular volume (ECV) fraction to predict the survival outcomes of pancreatic ductal adenocarcinoma (PDAC) patients with distant metastases (stage IV) treated with chemotherapy. METHODS: The study cohort included a total of 66 patients with stage IV PDAC who underwent DECT before systemic chemotherapy between July 2014 and March 2017. Unenhanced and 120-kVp equivalent images during the equilibrium phase were used to calculate tumor SECT-derived ECV fractions, and iodine density images were obtained from equilibrium-phase DECT for DECT-derived ECV fractions. Correlations between SECT- and DECT-derived ECV fractions were identified using the Pearson correlation coefficient and Bland-Altman analysis. The effects of clinical prognostic factors and tumor SECT- and DECT-derived ECV fractions on progression-free survival (PFS) and overall survival (OS) were assessed by univariate and multivariate analyses using Cox proportional hazards models. RESULTS: The correlation between SECT- and DECT-derived ECV fractions was strong (r = 0.965; p < 0.001). The Bland-Altman plot between SECT- and DECT-derived ECV fractions showed a small bias (- 3.4%). Increasing tumor SECT- and DECT-derived ECV fractions were associated with a positive effect on PFS (SECT, p = 0.002; DECT, p = 0.007) and OS (DECT, p = 0.014; DECT, p = 0.015). Only tumor DECT-derived ECV fraction was an independent predictor of PFS (p = 0.018) and OS (p = 0.022) in patients with stage IV PDAC treated with chemotherapy on multivariate analysis. CONCLUSIONS: The ECV fraction determined by equilibrium contrast-enhanced DECT can potentially predict the survival of patients with stage IV PDAC treated with chemotherapy. KEY POINTS: • Extracellular volume fraction of stage IV pancreatic ductal adenocarcinoma determined by dual-energy CT was strongly correlated to that with single-energy CT (r = 0.965, p < 0.001). • Tumor extracellular volume fraction was an independent predictor of progression-free survival (p = 0.018) and overall survival (p = 0.022). • Extracellular volume fraction determined by dual-energy CT could be a useful imaging biomarker to predict the survival of patients with stage IV pancreatic ductal adenocarcinoma treated with chemotherapy.

Response to neoadjuvant chemotherapy for breast cancer judged by PERCIST - multicenter study in Japan.

PURPOSE: The purpose of this study was to evaluate therapeutic response to neoadjuvant chemotherapy (NAC) and predict breast cancer recurrence using Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST). MATERIALS AND METHODS: Fifty-nine breast cancer patients underwent fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) before and after NAC prior to planned surgical resection. Pathological complete response (pCR) of the primary tumor was evaluated using PERCIST, while effects of clinicopathological factors on progression-free survival (PFS) were examined using log-rank and Cox methods. RESULTS: Fifty-six patients and 54 primary tumors were evaluated. Complete metabolic response (CMR), partial metabolic response, stable metabolic disease, and progressive metabolic disease were seen in 45, 7, 3, and 1 patients, respectively, and 43, 7, 3, and 1 primary tumors, respectively. Eighteen (33.3%) of the 54 primary tumors showed pCR. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PERCIST to predict pCR were 100% (18/18), 30.6% (11/36), 41.9% (18/43), 100% (11/11), and 53.7% (29/54), respectively. An optimal percent decrease in peak standardized uptake value for a primary tumor corrected for lean body mass (SULpeak) of 84.3% was found to have a sensitivity of 77.8% (14/18), specificity of 77.8% (28/36), PPV of 63.6% (14/22), NPV of 87.5% (28/32), and accuracy of 77.8% (42/54). Seven (12.5%) of the 56 patients developed recurrent disease (median follow-up 28.1 months, range 11.4-96.4 months). CMR (p = 0.031), pCR (p = 0.024), and early TNM stage (p = 0.033) were significantly associated with longer PFS. CONCLUSION: PERCIST is useful for predicting pathological response and prognosis following NAC in breast cancer patients. However, FDG-PET/CT showed a tendency toward underestimation of the residual tumor, and relatively low specificity and PPV of PERCIST showed that a combination of other imaging modalities would still be needed to predict pCR.

Impairment of Iodine-123-Metaiodobenzylguanidine (123I-MIBG) Uptake in Patients with Pulmonary Artery Hypertension.

According to recent studies, lung uptake of iodine-123-metaiodobenzylguanidine (123I-MIBG) is impaired in many lung diseases and low lung uptake of 123I-MIBG suggests endothelial dysfunction of the pulmonary artery. 123I-MIBG scintigraphy in patients with pulmonary hypertension (PH) has not yet been clinically evaluated. We hypothesized that the lung uptake of 123I-MIBG is reduced in patients with PH and differs among PH subtypes. The purpose of the present study was to analyze the lung uptake of 123I-MIBG in patients with PH and compare it with the data obtained by echocardiography or right heart catheterization. 123I-MIBG scintigraphy was performed in 286 consecutive patients from 2003 to 2014. We enrolled 21 patients with PH and 8 control patients. The 21 patients with PH were categorized into those with pulmonary artery hypertension (PAH, n = 12) and those with chronic thromboembolic pulmonary hypertension (CTEPH, n = 9). The mean pulmonary artery pressure was not significantly different between patients with CTEPH and PAH (37.7 ± 6.8 versus 32.3 ± 5.3 mmHg respectively; P = 0.054). There were no significant differences in any other hemodynamic parameters between the two groups. The lung uptake of 123I-MIBG in PAH patients (early image: 1.54 ± 0.18, delayed image: 1.41 ± 0.16) was significantly lower than that of CTEPH patients (early image: 2.17 ± 0.25, P < 0.0001; delayed image: 1.99 ± 0.20, P = 0.0001, adjusted for age and World Health Organization classification) and controls (early image: 2.32 ± 0.27, P = 0.0007; delayed image: 1.92 ± 0.19, P = 0.0007). In conclusion, we found for the first time that the lung uptake of 123I-MIBG in patients with PAH is lower than that in patients with CTEPH and controls.

A pilot study for texture analysis of 18F-FDG and 18F-FLT-PET/CT to predict tumor recurrence of patients with colorectal cancer who received surgery.

PURPOSE: This retrospective study was done to examine whether the heterogeneity in primary tumor F-18-fluorodeoxyglucose (18F-FDG) and 18F-3'-fluoro-3'-deoxythymidine (18F-FLT) distribution can predict prognosis of patients with colorectal cancer who received surgery. METHODS: The enrolled 32 patients with colorectal cancer underwent both 18F-FDG- and 18F-FLT-PET/CT studies before surgery. Clinicopathological factors, stage, SUVmax, SUVmean, metabolic tumor volume (SUV ≥ 2.5), total lesion glycolysis, total lesion proliferation and seven texture heterogeneity parameters (coefficient of variation, local parameters: entropy, homogeneity, and dissimilarity; and regional parameters: intensity variability [IV], size-zone variability [SZV], and zone percentage [ZP]) were obtained. Progression free survival (PFS) was calculated by the Kaplan-Meier method. Prognostic significance was assessed by Cox proportional hazards analysis. RESULTS: Eight patients had eventually come to progression, and 24 patients were alive without progression during clinical follow-up [mean follow-up PFS; 55.9 months (range, 1-72)]. High stage (p = 0.004), high 18F-FDG-IV (p = 0.015), high 18F-FDG-SZV (p = 0.013) and high 18F-FLT-entropy (p = 0.015) were significant in predicting poor 5-year PFS. Other parameters did not predict the disease outcome. At bivariate analysis, disease event hazards ratios for 18F-FDG-IV and 18F-FDG-SZV remained significant when adjusted for stage and 18F-FLT-entropy (18F-FDG-IV; p = 0.004 [adjusted for stage], 0.007 [adjusted for 18F-FLT-entropy]; 18F-FDG-SZV; p = 0.028 [adjusted for stage], 0.040 [adjusted for 18F-FLT-entropy]). CONCLUSION: 18F-FDG PET heterogeneity parameters, IV and SZV, have a potential to be strong prognostic factors to predict PFS of patients with surgically resected colorectal cancer and are more useful than 18F-FLT-PET/CT heterogeneity parameters.

Texture analysis of 18F-FDG PET/CT to predict tumour response and prognosis of patients with esophageal cancer treated by chemoradiotherapy.

PURPOSE: This retrospective study was done to examine whether the heterogeneity in primary tumour F-18-fluorodeoxyglucose (18F-FDG) distribution can predict tumour response and prognosis of patients with esophageal cancer treated by chemoradiotherapy (CRT). METHODS: The enrolled 52 patients with esophageal cancer underwent 18F-FDG-PET/CT studies before CRT. SUVmax, SUVmean, metabolic tumour volume (MTV, SUV ≥ 2.5), total lesion glycolysis (TLG) and six heterogeneity parameters assessed by texture analysis were obtained. Patients were classified as responders or non-responders according to Response Evaluation Criteria in Solid Tumors. Progression-free survival (PFS) and overall survival (OS) were calculated by the Kaplan-Meier method. Prognostic significance was assessed by Cox proportional hazards analysis. RESULTS: Thirty four non-responders showed significantly higher MTV (p = 0.006), TLG (p = 0.007), intensity variability (IV; p = 0.003) and size-zone variability (SZV; p = 0.004) than 18 responders. The positive and negative predictive values for non-responders were 77 % and 69 % in MTV, 76 % and 100 % in TLG, 78 % and 67 % in IV and 78 % and 82 % in SZV, respectively. Although PFS and OS were significantly shorter in patients with high MTV (PFS, p = 0.018; OS, p = 0.014), TLG (PFS, p = 0.009; OS, p = 0.025), IV (PFS, p = 0.013; OS, p = 0.007) and SZV (PFS, p = 0.010; OS, p = 0.007) at univariate analysis, none of them was an independent factor, while lymph node status, stage and tumour response status were independent factors at multivariate analysis. CONCLUSION: Texture features IV and SZV, and volumetric parameters MTV and TLG can predict tumour response, but all of them have limited value in prediction of prognosis of patients with esophageal cancer treated by CRT.

ADC histogram analysis for adrenal tumor histogram analysis of apparent diffusion coefficient in differentiating adrenal adenoma from pheochromocytoma.

PURPOSE: To determine the diagnostic performance of apparent diffusion coefficient (ADC) histogram analysis in diffusion-weighted (DW) magnetic resonance imaging (MRI) for differentiating adrenal adenoma from pheochromocytoma. MATERIALS AND METHODS: We retrospectively evaluated 52 adrenal tumors (39 adenomas and 13 pheochromocytomas) in 47 patients (21 men, 26 women; mean age, 59.3 years; range, 16-86 years) who underwent DW 3.0T MRI. Histogram parameters of ADC (b-values of 0 and 200 [ADC200 ], 0 and 400 [ADC400 ], and 0 and 800 s/mm2 [ADC800 ])-mean, variance, coefficient of variation (CV), kurtosis, skewness, and entropy-were compared between adrenal adenomas and pheochromocytomas, using the Mann-Whitney U-test. Receiver operating characteristic (ROC) curves for the histogram parameters were generated to differentiate adrenal adenomas from pheochromocytomas. Sensitivity and specificity were calculated by using a threshold criterion that would maximize the average of sensitivity and specificity. RESULTS: Variance and CV of ADC800 were significantly higher in pheochromocytomas than in adrenal adenomas (P < 0.001 and P = 0.001, respectively). With all b-value combinations, the entropy of ADC was significantly higher in pheochromocytomas than in adrenal adenomas (all P ≤ 0.001), and showed the highest area under the ROC curve among the ADC histogram parameters for diagnosing adrenal adenomas (ADC200 , 0.82; ADC400 , 0.87; and ADC800 , 0.92), with sensitivity of 84.6% and specificity of 84.6% (cutoff, ≤2.82) with ADC200 ; sensitivity of 89.7% and specificity of 84.6% (cutoff, ≤2.77) with ADC400 ; and sensitivity of 94.9% and specificity of 92.3% (cutoff, ≤2.67) with ADC800 . CONCLUSION: ADC histogram analysis of DW MRI can help differentiate adrenal adenoma from pheochromocytoma. LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:1195-1203.

Present and future roles of FDG-PET/CT imaging in the management of gastrointestinal cancer: an update.

Positron emission tomography/computed tomography (PET/CT) integrated with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) is a useful tool for acquisition of both glucose metabolism and anatomic imaging data, as only a single device and one diagnostic session is required, thus opening a new field in clinical oncologic imaging. FDG-PET/CT has been successfully used for initial staging, restaging, assessment of early treatment response, evaluation of metastatic disease response, and prognostication of intestinal cancer as well as various malignant tumors. We reviewed the current status and role of FDG-PET/CT for management of patients with esophageal cancer, gastric cancer, and colorectal cancer, with focus on both its usefulness and limitations.

Dexamethasone Suppression FDG PET/CT for Differentiating between True- and False-Positive Pulmonary and Mediastinal Lymph Node Metastases in Non-Small Cell Lung Cancer: A Pilot Study of FDG PET/CT after Oral Administration of Dexamethasone.

PURPOSE: To examine whether dexamethasone suppression can reduce fluorine 18 fluorodeoxyglucose (FDG) uptake in false-positive (FP) findings in pulmonary and mediastinal lymph nodes in non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Institutional ethics review board approved this prospective study with written informed consent. The study population was composed of 17 patients with NSCLC who underwent both baseline and dexamethasone suppression (24 hours after oral administration of 8 mg dexamethasone) FDG positron emission tomography/computed tomography and surgery. FDG uptake was evaluated by using a five-point visual scoring system (negative findings, score of 0-1; positive findings, score of 2-4) and maximum standardized uptake value (SUVmax). The Mann-Whitney U, Wilcoxon signed-rank, Kruskal-Wallis, or Spearman rank correlation tests were used as necessary for statistical evaluations. RESULTS: In 17 primary lesions, no significant difference was noted in visual score between baseline (mean, 3.4 ± 1.2) and dexamethasone suppression scans (mean, 3.3 ± 1.2; P = .16), although SUVmax was significantly lower on dexamethasone suppression scans (mean, 7.1 ± 5.2) than on baseline scans (mean, 8.6 ± 6.6; P = .005). In eight nodes with true-positive (TP) findings, there were no significant differences in visual score (mean for both, 3.8 ± 0.5) and SUVmax (mean, 5.3 ± 2.3 vs 5.5 ± 2.5, respectively; P = .81) between baseline and dexamethasone suppression scans. In 19 nodes with FP findings at baseline, dexamethasone suppression resulted in significantly lowered visual score (mean, 3.4 ± 0.6 vs 2.4 ± 0.8, respectively; P < .001) and SUVmax (mean, 3.5 ± 0.8 vs 2.7 ± 0.7, respectively; P < .001), and four nodes with FP findings were rated as true-negative findings on dexamethasone suppression scans, which resulted in a significant difference in SUVmax between nodal lesions with TP and FP findings (P = .014). CONCLUSION: Oral dexamethasone has the potential to reduce FDG uptake in pulmonary and mediastinal nodes with FP findings in NSCLC.

FDG-PET/CT and FLT-PET/CT for differentiating between lipid-poor benign and malignant adrenal tumours.

OBJECTIVE: To compare F-18-fluorodeoxyglucose (FDG) and F-18-fluorothymidine (FLT) PET/CT examinations for differentiating between benign and malignant adrenal tumours. METHODS: Thirty lipid-poor benign and 11 malignant tumours of 40 patients were included. FDG- and FLT-based indices including visual score, maximum standardized uptake value (SUVmax) and FDG adrenal lesion/liver SUVmax (A/L SUVmax) or FLT adrenal lesion/back muscle SUVmax (A/B SUVmax) ratio were compared between benign and malignant tumours using the Mann-Whitney's U or Wilcoxon signed-rank test, and their diagnostic performances were evaluated by means of the area under the curve (AUC) values derived from the receiver operating characteristic analysis. RESULTS: All indices were significantly higher in malignant than benign tumours on both images (p < 0.05 each). On FDG-PET/CT, the sensitivity, specificity, and accuracy were 91 %, 63 % and 71 % for visual score, 91 %, 67 % and 73 % for SUVmax, and 100 %, 70 % and 78 % for A/L SUVmax ratio, respectively. On FLT-PET/CT, they were 100 %, 97 % and 98 % for visual score, SUVmax and A/B SUVmax ratio, respectively. All FLT indices were significantly higher than those of FDG in AUC (p < 0.05 each). CONCLUSION: FLT-PET/CT may be superior to FDG-PET/CT in differentiating lipid-poor benign from malignant adrenal tumours because of higher specificity and accuracy. KEY POINTS: • All FDG indices were significantly higher in malignant than in benign tumours. • All FLT indices were significantly higher in malignant than in benign tumours. • All FLT indices were significantly higher than those of FDG in AUC.

Diagnostic performances of FDG-PET/CT and diffusion-weighted imaging indices for differentiating benign pheochromocytoma from other benign adrenal tumors.

PURPOSE: The purpose of this study is to compare diagnostic performances of (18)F-fluorodeoxyglucose (FDG) visual score, maximum standardized uptake value (SUVmax), ratio of adrenal SUVmax to liver SUVmax (A/L SUVmax), apparent diffusion coefficient (ADC) from diffusion-weighted imaging, and SUVmax/ADC ratio to differentiate adrenal pheochromocytoma from other benign tumors. METHODS: Eleven pheochromocytomas and 22 other benign tumors in 30 patients were included. FDG-based indices, ADC, and SUVmax/ADC ratio were compared between groups using the Mann-Whitney U test, and sensitivity, specificity, accuracy, and area under the curve (AUC) for diagnosing pheochromocytoma by receiver operating characteristic analyses. The correlation between SUVmax and ADC was analyzed using the Spearman's rank test. RESULTS: Pheochromocytoma showed significantly higher visual score (2.8 ± 0.4 vs. 1.3 ± 0.9), SUVmax (11.0 ± 8.9 vs. 3.2 ± 1.4), A/L SUVmax ratio (3.96 ± 3.48 vs. 0.96 ± 0.51), and SUVmax/ADC ratio (10.6 ± 8.09 vs. 2.28 ± 0.98) (each P < 0.001) and significantly lower ADC (1.08 ± 0.23 × 10(-3) mm(2)/s vs. 1.43 ± 0.29 × 10(-3) mm(2)/s, P = 0.003) than other benign tumors. Sensitivity, specificity, and accuracy for diagnosing pheochromocytoma were 100, 73, and 82% for visual score, 100, 86, and 91% for both SUVmax and A/L SUVmax ratio, and 64, 100, and 88% for ADC and 82, 95, and 91% for SUVmax/ADC ratio. No significant differences in AUC were found between FDG-based indices, ADC, and SUVmax/ADC ratio. A significant negative correlation was noted between SUVmax and ADC (ρ = -0.36, P = 0.039). CONCLUSION: FDG-based indices and ADC appear comparably useful for differentiating pheochromocytoma from other benign adrenal tumors.

Correlations of (18)F-fluorothymidine uptake with pathological tumour size, Ki-67 and thymidine kinase 1 expressions in primary and metastatic lymph node colorectal cancer foci.

OBJECTIVE: To examine correlations of (18)F-fluorothymidine (FLT) uptake with pathological tumour size and immunohistochemical Ki-67, and thymidine kinase 1 (TK-1) expressions in primary and metastatic node colorectal cancer foci. METHODS: Thirty primary cancers (PCs) and 37 metastatic nodes (MNs) were included. FLT uptake was assessed by visual scores (non-visible: 0-1 and visible: 2-4), standardized uptake value (SUV), and correlated with size, Ki-67, and TK-1. SUV was measured in visible lesions. FLT heterogeneity was assessed by visual scores (no heterogeneous uptake: 0 and heterogeneous uptake: 1-4). RESULTS: Forty-two lesions were visible. The visible group showed significantly higher values than the non-visible group in size, Ki-67, and TK-1 (each p < 0.05). Size correlated significantly with visual score (PC; ρ = 0.74 and MN; ρ = 0.63), SUVmax (PC; ρ = 0.49, and MN; ρ = 0.76), and SUVmean (PC; ρ = 0.40 and MN; ρ = 0.76) (each p < 0.05). Visual score correlated significantly with size (ρ = 0.86), Ki-67max (ρ = 0.35), Ki-67mean (ρ = 0.38), TK-1max (ρ = 0.35) and TK-1mean (ρ = 0.25) (each p < 0.05). No significant correlations were found between FLT uptake and Ki-67 or TK-1 in 42 visible lesions (each p > 0.05). Heterogeneous FLT uptake was noted in 73 % (22/30) of PCs. CONCLUSION: FLT uptake correlated with size. Heterogeneous FLT distribution in colorectal cancers may be one of the causes of weak or lack of FLT uptake/Ki-67 or TK-1 correlation. KEY POINTS: FLT uptake correlated well with tumour size in colorectal cancer. Weak or lack of FLT uptake/Ki-67 and TK-1 correlations were observed. Immunohistochemical Ki-67 and TK-1 expressions are not always correlated with FLT uptake.

Effects and safety of ¹³¹I-metaiodobenzylguanidine (MIBG) radiotherapy in malignant neuroendocrine tumors: results from a multicenter observational registry.

Effective treatments for malignant neuroendocrine tumors are under development. While iodine-131 metaiodobenzylguanidine (¹³¹I-MIBG) radiotherapy has been used in the treatment of malignant neuroendocrine tumors, there are few studies evaluating its therapeutic effects and safety in a multicenter cohort. In the current study, we sought to evaluate the effects and safety of ¹³¹I-MIBG therapy for conditions including malignant pheochromocytoma and paraganglioma within a multicenter cohort. Forty-eight malignant neuroendocrine tumors (37 pheochromocytoma and 11 paraganglioma) from four centers underwent clinical ¹³¹I-MIBG radiotherapy. The tumor responses were observed before and 3 to 6 months after the ¹³¹I-MIBG radiotherapy in accordance with RECIST criteria. We also evaluated the data for any adverse effects. The four centers performed a total of 87 ¹³¹I-MIBG treatments on 48 patients between January 2000 and March 2009. Of the treatments, 65 were evaluable using RECIST criteria. One partial response (PR), 40 stable disease (SD), and 9 progressive disease (PD) in malignant pheochromocytoma were observed after each treatment. Fourteen SD and one PD-were observed in paraganglioma. Patients with normal hypertension (systolic blood pressure (BP) > 130 mmHg) showed significantly reduced systolic BP after the initial follow-up (n=10, 138.1±8.2 to 129.5±13.5 mmHg, P=0.03). In adult neuroendocrine tumors with a treatment-basis analysis, there were side effects following 41 treatments (47.1%) and most of them (90.2%) were minor. In this multicenter registry, PR or SD was achieved in 84.6% of the treatment occasions in adult neuroendocrine tumors through ¹³¹I-MIBG radiotherapy. This indicated that most of the ¹³¹I-MIBG radiotherapy was performed safely without significant side effects.

Clinical application of 18F-fluorodeoxyglucose positron emission tomography/computed tomography radiomics-based machine learning analyses in the field of oncology.

Machine learning (ML) analyses using 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) radiomics features have been applied in the field of oncology. The current review aimed to summarize the current clinical articles about 18F-FDG PET/CT radiomics-based ML analyses to solve issues in classifying or constructing prediction models for several types of tumors. In these studies, lung and mediastinal tumors were the most commonly evaluated lesions, followed by lymphatic, abdominal, head and neck, breast, gynecological, and other types of tumors. Previous studies have commonly shown that 18F-FDG PET radiomics-based ML analysis has good performance in differentiating benign from malignant tumors, predicting tumor characteristics and stage, therapeutic response, and prognosis by examining significant differences in the area under the receiver operating characteristic curves, accuracies, or concordance indices (> 0.70). However, these studies have reported several ML algorithms. Moreover, different ML models have been applied for the same purpose. Thus, various procedures were used in 18F-FDG PET/CT radiomics-based ML analysis in oncology, and 18F-FDG PET/CT radiomics-based ML models, which are easy and universally applied in clinical practice, would be expected to be established.

Adult T-cell Leukemia/Lymphoma (ATL) in the Nasal and Paranasal Cavity: Four Cases Report.

Adult T-cell leukemia/lymphoma (ATL) is a form of leukemia caused by the human T-cell leukemia virus type I (HTLV-1). Otolaryngologists often diagnose ATL based on cervical lymphadenopathy or Waldeyer ring lesions. However, there are few reports of ATL occurring in the nasal and paranasal cavity. Here, we report four such cases of ATL. Case 1: An 82-year-old man diagnosed with acute-type ATL with a tumor in the nasal cavity underwent 5 courses of THP-COP, but died after 36 months due to ATL. Case 2: A 62-year-old woman diagnosed with lymphoma-type ATL with a tumor in the frontal sinus was treated with 5 courses of VCAP-AMP-VECP, and has survived for more than 10 years. Case 3: A 64-year-old man diagnosed with lymphoma-type ATL with a tumor in the maxillary sinus underwent 8 courses of VCAP-AMP-VECP and 2 courses of mogamulizumab, but died after 34 months due to ATL. Case 4: A 52-year-old woman diagnosed with lymphoma-type ATL with tumors in both ethmoid sinuses received 2 courses of CHOP, 2 courses of DeVIC, radiotherapy (32 Gy) and 2 courses of mogamulizumab, but died after 9 months due to ATL.

Nuclear medicine practice in Japan: a report of the ninth nationwide survey in 2022.

Subcommittee on Survey of Nuclear Medicine Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5 years since 1982 to survey contemporary nuclear medicine practice and its changes over the years. The subcommittee sent questionnaires, including the number and category of examinations as well as the kind of the radiopharmaceuticals during the 30 days of June 2022 to all nuclear medicine institutes in Japan. The total numbers of them for the year 2022 were estimated depends on the 1-month data. A total of 1095 institutes responded to the survey, including 364 positron emission tomography (PET) centers. The recovery rate was 90.6%. The number of gamma cameras installed was 1299 in total, with 2.5% decrease in 5 years. Dual-head cameras and hybrid SPECT/CT scanners accounted for 83.8% and 35.5%, respectively. The number of single-photon tracer studies in 2022 was 1.11 million which means increase in 2.7% in 5 years. Bone scintigraphy was a leading examination (31.0%), followed by myocardial scintigraphy (27.1%) and cerebral perfusion study (23.8%) in order. The percentage of SPECT studies showed an increase from 63.5% in previous survey to 66.8% in this survey. PET centers have also increased from 389 to 412, as compared with the previous one. One hundred and twenty-two PET centers have installed one or two in-house cyclotrons. Increasing trends of the PET studies were observed from 1992 to 2017, the trend changed and PET studies showed 1.5% decrease in 5 years. 18F-FDG accounted for 98.6% (610,497 examinations). PET examinations using 11C-methionine, 13N-NH3 and 11C-PIB have decreased, with 1624, 2146 and 525 examinations, respectively in 2022. The total number of nuclear medicine examination was eventually increased by 1.0%. Therapies for pheochromocytoma or paraganglioma (PPGL) with 131I-MIBG and for neuroendocrine tumor with 177Lu-DOTA-TATE were newly started, however, a total number of targeted radionuclide therapy was decreased by 17.7% because 131I-radioiodine and 223Ra targeted therapies were decreased and supply of some radioisotopes was discontinued. 131I-radioiodine targeted therapy showed a decrease in 5 years (- 15.9%), including 4099 patients for thyroid cancer. The number of out-patient thyroid bed ablation therapy with 1110 MBq of 131I was also decreased to 1015 per year. The number of admission rooms specialized for radionuclide targeted therapy increased from 157 to 160. The number of 223Ra targeted therapies for castration-resistant metastatic prostate cancer (mCRPC) was 1041 patients. This survey was performed during COVID-19 pandemic, however, total number of nuclear medicine examinations was almost same as previous survey (+ 1.0%). Radionuclide therapies with 131I-MIBG and 177Lu-DOTA-TATE were newly started, and new radionuclide therapy will be available in future, therefore, the development of radionuclide therapy will be continued. We are convinced that this survey report is useful in understanding the current status of the nuclear medicine practice in Japan, and in devising the new strategy to strengthen a role of nuclear medicine.