Combination of FDG PET/CT Radiomics and Clinical Parameters for Outcome Prediction in Patients with Hodgkin's Lymphoma.

PURPOSE: The aim of the study is to evaluate the prognostic value of a joint evaluation of PET and CT radiomics combined with standard clinical parameters in patients with HL. METHODS: Overall, 88 patients (42 female and 46 male) with a median age of 43.3 (range 21-85 years) were included. Textural analysis of the PET/CT images was performed using freely available software (LIFE X). 65 radiomic features (RF) were evaluated. Univariate and multivariate models were used to determine the value of clinical characteristics and FDG PET/CT radiomics in outcome prediction. In addition, a binary logistic regression model was used to determine potential predictors for radiotherapy treatment and odds ratios (OR), with 95% confidence intervals (CI) reported. Features relevant to survival outcomes were assessed using Cox proportional hazards to calculate hazard ratios with 95% CI. RESULTS: albumin (p = 0.034) + ALP (p = 0.028) + CT radiomic feature GLRLM GLNU mean (p = 0.012) (Area under the curve (AUC): 95% CI (86.9; 100.0)-Brier score: 3.9, 95% CI (0.1; 7.8) remained significant independent predictors for PFS outcome. PET-SHAPE Sphericity (p = 0.033); CT grey-level zone length matrix with high gray-level zone emphasis (GLZLM SZHGE mean (p = 0.028)); PARAMS XSpatial Resampling (p = 0.0091) as well as hemoglobin results (p = 0.016) remained as independent factors in the final model for a binary outcome as predictors of the need for radiotherapy (AUC = 0.79). CONCLUSION: We evaluated the value of baseline clinical parameters as well as combined PET and CT radiomics in HL patients for survival and the prediction of the need for radiotherapy treatment. We found that different combinations of all three factors/features were independently predictive of the here evaluated endpoints.

Nasopharyngeal Carcinoma Radiomic Evaluation with Serial PET/CT: Exploring Features Predictive of Survival in Patients with Long-Term Follow-Up.

PURPOSE: We aim determine the value of PET and CT radiomic parameters on survival with serial follow-up PET/CT in patients with nasopharyngeal carcinoma (NPC) for which curative intent therapy is undertaken. METHODS: Patients with NPC and available pre-treatment as well as follow up PET/CT were included from 2005 to 2006 and were followed to 2021. Baseline demographic, radiological and outcome data were collected. Univariable Cox proportional hazard models were used to evaluate features from baseline and follow-up time points, and landmark analyses were performed for each time point. RESULTS: Sixty patients were enrolled, and two-hundred and seventy-eight (278) PET/CT were at baseline and during follow-up. Thirty-eight percent (38%) were female, and sixty-two patients were male. All patients underwent curative radiation or chemoradiation therapy. The median follow-up was 11.72 years (1.26-14.86). Five-year and ten-year overall survivals (OSs) were 80.0% and 66.2%, and progression-free survival (PFS) was 90.0% and 74.4%. Time-dependent modelling suggested that, among others, PET gray-level zone length matrix (GLZLM) gray-level non-uniformity (GLNU) (HR 2.74 95% CI 1.06, 7.05) was significantly associated with OS. Landmark analyses suggested that CT parameters were most predictive at 15 month, whereas PET parameters were most predictive at time points 3, 6, 9 and 15 month. CONCLUSIONS: This study with long-term follow up data on NPC suggests that mainly PET-derived radiomic features are predictive for OS but not PFS in a time-dependent evaluation. Furthermore, CT radiomic measures may predict OS and PFS best at initial and long-term follow-up time points and PET measures may be more predictive in the interval. These modalities are commonly used in NPC surveillance, and prospective validation should be considered.

Diagnostic performance of [18F]-FDG PET/MR in evaluating colorectal cancer: a systematic review and meta-analysis.

PURPOSE: To calculate the diagnostic performance of [18F]-FDG PET/MR in colorectal cancer (CRC). METHODS: This study was designed following the PRISMA-DTA guidelines. To be included, published original articles (until December 31, 2021) that met the following criteria were considered eligible: (1) evaluated [18F]-FDG PET/MR as the diagnostic method to detect CRC; (2) compared [18F]-FDG PET/MR with histopathology as the reference standard, or clinical/imaging composite follow-up when pathology was not available; (3) provided adequate crude data for meta-analysis. The diagnostic pooled measurements were calculated at patient and lesion levels. Regarding sub-group analysis, diagnostic measurements were calculated in "TNM staging," "T staging," "N staging," "M staging," and "liver metastasis" sub-groups. Additionally, we calculated the pooled performances in "rectal cancer: patient-level" and "rectal cancer: lesion-level" sub-groups. A hierarchical method was used to pool the performances. The bivariate model was conducted to find the summary points. Analyses were performed using STATA 16. RESULTS: A total of 1534 patients from 18 studies were entered. The pooled sensitivities in CRC lesion detection (tumor, lymph nodes, and metastases) were 0.94 (95%CI: 0.89-0.97) and 0.93 (95%CI: 0.82-0.98) at patient-level and lesion-level, respectively. The pooled specificities were 0.89 (95%CI: 0.84-0.93) and 0.95 (95%CI: 0.90-0.98) at patient-level and lesion-level, respectively. In sub-groups, the highest sensitivity (0.97, 95%CI: 0.86-0.99) and specificity (0.99, 95%CI: 0.84-1.00) were calculated for "M staging" and "rectal cancer: lesion-level," respectively. The lowest sensitivity (0.81, 95%CI: 0.65-0.91) and specificity (0.79, 95%CI: 0.52-0.93) were calculated for "N staging" and "T staging," respectively. CONCLUSION: This meta-analysis showed an overall high diagnostic performance for [18F]-FDG PET/MR in detecting CRC lesions/metastases. Thus, this modality can play a significant role in several clinical scenarios in CRC staging and restaging. Specifically, one of the main strengths of this modality is ruling out the existence of CRC lesions/metastases. Finally, the overall diagnostic performance was not found to be affected in the post-treatment setting.

Combined 18 F-FDG PET/CT Radiomics and Sarcopenia Score in Predicting Relapse-Free Survival and Overall Survival in Patients With Esophagogastric Cancer.

PURPOSE: The aim of this study was to determine if radiomic features combined with sarcopenia measurements on pretreatment 18 F-FDG PET/CT can improve outcome prediction in surgically treated adenocarcinoma esophagogastric cancer patients. PATIENTS AND METHODS: One hundred forty-five esophageal adenocarcinoma patients with curative therapeutic intent and available pretreatment 18 F-FDG PET/CT were included. Textural features from PET and CT images were evaluated using LIFEx software ( lifexsoft.org ). Sarcopenia measurements were done by measuring the Skeletal Muscle Index at L3 level on the CT component. Univariable and multivariable analyses were conducted to create a model including the radiomic parameters, clinical features, and Skeletal Muscle Index score to predict patients' outcome. RESULTS: In multivariable analysis, we combined clinicopathological parameters including ECOG, surgical T, and N staging along with imaging derived sarcopenia measurements and radiomic features to build a predictor model for relapse-free survival and overall survival. Overall, adding sarcopenic status to the model with clinical features only (likelihood ratio test P = 0.03) and CT feature ( P = 0.0037) improved the model fit for overall survival. Similarly, adding sarcopenic status ( P = 0.051), CT feature ( P = 0.042), and PET feature ( P = 0.011) improved the model fit for relapse-free survival. CONCLUSIONS: PET and CT radiomics derived from combined PET/CT integrated with clinicopathological parameters and sarcopenia measurement might improve outcome prediction in patients with nonmetastatic esophagogastric adenocarcinoma.

Human-level COVID-19 diagnosis from low-dose CT scans using a two-stage time-distributed capsule network.

Reverse transcription-polymerase chain reaction is currently the gold standard in COVID-19 diagnosis. It can, however, take days to provide the diagnosis, and false negative rate is relatively high. Imaging, in particular chest computed tomography (CT), can assist with diagnosis and assessment of this disease. Nevertheless, it is shown that standard dose CT scan gives significant radiation burden to patients, especially those in need of multiple scans. In this study, we consider low-dose and ultra-low-dose (LDCT and ULDCT) scan protocols that reduce the radiation exposure close to that of a single X-ray, while maintaining an acceptable resolution for diagnosis purposes. Since thoracic radiology expertise may not be widely available during the pandemic, we develop an Artificial Intelligence (AI)-based framework using a collected dataset of LDCT/ULDCT scans, to study the hypothesis that the AI model can provide human-level performance. The AI model uses a two stage capsule network architecture and can rapidly classify COVID-19, community acquired pneumonia (CAP), and normal cases, using LDCT/ULDCT scans. Based on a cross validation, the AI model achieves COVID-19 sensitivity of [Formula: see text], CAP sensitivity of [Formula: see text], normal cases sensitivity (specificity) of [Formula: see text], and accuracy of [Formula: see text]. By incorporating clinical data (demographic and symptoms), the performance further improves to COVID-19 sensitivity of [Formula: see text], CAP sensitivity of [Formula: see text], normal cases sensitivity (specificity) of [Formula: see text] , and accuracy of [Formula: see text]. The proposed AI model achieves human-level diagnosis based on the LDCT/ULDCT scans with reduced radiation exposure. We believe that the proposed AI model has the potential to assist the radiologists to accurately and promptly diagnose COVID-19 infection and help control the transmission chain during the pandemic.

Influence of sarcopenia, clinical data, and 2-[18F] FDG PET/CT in outcome prediction of patients with early-stage adenocarcinoma esophageal cancer.

PURPOSE: To determine the prognostic value of sarcopenia measurements done on staging 2-[18F] FDG PET/CT together with metabolic activity of the tumor in patients with adenocarcinoma esophagogastric cancer with surgical treatment. METHODS: Patients with early-stage, surgically treated esophageal adenocarcinoma and available pre-treatment 2-[18F] FDG PET/CT were included. The standard uptake value (SUV) and SUV normalized by lean body mass (SUL) were recorded. Skeletal muscle index (SMI) was measured at the L3 level on the CT component of the PET/CT. Sarcopenia was defined as SMI < 34.4cm2/m2 in women and < 45.4cm2/m2 in men. RESULTS: Of the included 145 patients. 30% were sarcopenic at baseline. On the univariable Cox proportional hazards analysis, ECOG, surgical T and N staging, lymphovascular invasion (LVI) positive lymph nodes, and sarcopenia were significant prognostic factors concerning RFS and OS. On multivariable Cox regression analysis, surgical N staging (p = 0.025) and sarcopenia (p = 0.022) remained significant poor prognostic factors for OS and RFS. Combining the clinical parameters with the imaging-derived nutritional evaluation of the patient but not metabolic parameters of the tumor showed improved predictive ability for OS and RFS. CONCLUSION: Combining the patients' imaging-derived sarcopenic status with standard clinical data, but not metabolic parameters, offered an overall improved prognostic value concerning OS and RFS.

Detection of clinically significant prostate cancer with 18F-DCFPyL PET/multiparametric MR.

PURPOSE: To assess whether 18F-DCFPyL PET/multiparametric (mp)MR contributes to the diagnosis of clinically significant (cs) prostate cancer (PCa) compared to mpMR in patients with suspicion of PCa, or patients being considered for focal ablative therapies (FT). PATIENTS AND METHODS: This ethics review board-approved, prospective study included 55 men with suspicion of PCa and negative systematic biopsies or clinically discordant low-risk PCa (n = 21) or those being considered for FT (n = 34) who received 18F-DCFPyL PET/mpMR. Each modality, PET, mpMR, and PET/MR (using the PROMISE classification), was assessed independently. All suspicious lesions underwent PET/MR-ultrasound fusion biopsies. RESULTS: There were 45/55 patients (81.8%) that had histologically proven PCa and 41/55 (74.5%) were diagnosed with csPCa. Overall, 61/114 lesions (53.5%) identified on any modality were malignant; 49/61 lesions (80.3%) were csPCa. On lesion-level analysis, for detection of csPCa, the sensitivity of PET was higher than that of mpMR and PET/MR (86% vs 67% and 69% [p = 0.027 and 0.041, respectively]), but at a lower specificity (32% vs 85% and 86%, respectively [p < 0.001]). The performance of MR and PET/MR was comparable. For identification of csPCa in PI-RADS ≥ 3 lesions, the AUC (95% CI) for PET, mpMR, and PET/MR was 0.75 (0.65-0.86), 0.69 (0.56-0.82), and 0.78 (0.67-0.89), respectively. The AUC for PET/MR was significantly larger than that of mpMR (p = 0.04). CONCLUSION: PSMA PET detects more csPCa than mpMR, but at low specificity. The performance PET/MR is better than mpMR for detection of csPCa in PI-RADS ≥ 3 lesions. CLINICAL REGISTRATION: NCT03149861.

Quantitative 68Ga-DOTATATE PET/CT Parameters for the Prediction of Therapy Response in Patients with Progressive Metastatic Neuroendocrine Tumors Treated with 177Lu-DOTATATE.

The aim of this study was to determine whether quantitative PET parameters on baseline 68Ga-DOTATATE PET/CT and interim PET (iPET) performed before the second cycle of therapy are predictive of the therapy response and progression-free survival (PFS). Methods: Ninety-one patients with well-differentiated neuroendocrine tumors (mean Ki-67 index, 8.3%) underwent 68Ga-DOTATATE PET/CT to determine suitability for peptide receptor radionuclide therapy as part of a prospective multicenter study. The mean follow-up was 12.2 mo. Of the 91 patients, 36 had iPET. The tumor metrics evaluated were marker lesion-based measures (mean SUVmax and ratio of the mean lesion SUVmax to the SUVmax in the liver or the SUVmax in the spleen), segmented 68Ga-DOTATATE tumor volumes (DTTVs), SUVmax and SUVmean obtained with the liver and spleen as thresholds, and heterogeneity parameters (coefficient of variation, kurtosis, and skewness). The Wilcoxon rank sum test was used for the association between continuous variables and the therapy response, as determined by the clinical response. Univariable and multivariable Cox proportional hazards models were used for the association with PFS. Results: There were 71 responders and 20 nonresponders. When marker lesions were used, higher mean SUVmax and ratio of the mean lesion SUVmax to the SUVmax in the liver were predictors of the therapy response (P = 0.018 and 0.024, respectively). For DTTV parameters, higher SUVmax and SUVmean obtained with the liver as a threshold and lower kurtosis were predictors of a favorable response (P = 0.025, 0.0055, and 0.031, respectively). The latter also correlated with a longer PFS. The iPET DTTV SUVmean obtained with the liver as a threshold and the ratio of mean SUVmax obtained from target lesions at iPET to baseline PET correlated with the therapy response (P = 0.024 and 0.048, respectively) but not PFS. From the multivariable analysis with adjustment for age, primary site, and Ki-67 index, the mean SUVmax (P = 0.019), ratio of the mean lesion SUVmax to the SUVmax in the liver (P = 0.018), ratio of the mean lesion SUVmax to the SUVmax in the spleen (P = 0.041), DTTV SUVmean obtained with the liver (P = 0.0052), and skewness (P = 0.048) remained significant predictors of PFS. Conclusion: The degree of somatostatin receptor expression and tumor heterogeneity, as represented by several metrics in our analysis, were predictive of the therapy response or PFS. Changes in these parameters after the first cycle of peptide receptor radionuclide therapy did not correlate with clinical outcomes.

Ultra-low dose CT abdomen and pelvis for the detection of acute abdominal pathology in the emergency room: initial experience from an academic hospital.

PURPOSE: The aim of this study is to describe our initial experience using ULDCT performed in the emergency room in the evaluation of acute abdominal pathology. METHODS: Data from consecutive patients who underwent ULDCT for assessment of bowel obstruction, free intraperitoneal air, unexplained abdominal pain, or fecal loading for constipation between June 1, 2016 and March 31, 2017 was retrospectively assessed. Demographic data, radiation dose, CT findings, and clinical outcomes including performance of full dose contrast-enhanced CT (CECT), hospitalization, and surgery was collected. Concordance of ULDCT to CECT was calculated. RESULTS: ULDCT was performed in 325 patients (188 women and 137 men; mean age, 65.1 years). ULDCT detected acute abdominal pathology in 134/325 (41.2%), and in 89/134 (66.4%) it was concordant with the clinical working diagnosis. The average dose length product (DLP) was 101.6 mGy cm (range 51.7-614; median, 82.6). CECT was performed in 44/325 patients (13.5%). In 7/44 (15.9%), CECT identified discordant findings which likely impacted management. A greater proportion of patients were admitted to hospital after a positive ULDCT 99/137 (72.3%), compared to those with a negative study 81/188 (43.1%); p < 0.0001(Chi2, 27.30). Of those admitted to hospital, 11/99 (11.1%) with positive ULDCT had surgery compared to 1/81 (1.2%) with a negative ULDCT; p < 0.008 (Chi2, 6.98). CONCLUSION: With its high clinical yield and similar radiation dose, ULDCT appears as a suitable alternative to abdominal radiography for the detection of select acute abdominal pathology in the emergency room.

Prognostic significance of nutritional markers in metastatic gastric and esophageal adenocarcinoma.

BACKGROUND: Malnutrition and sarcopenia are poor prognostic factors in many cancers. Studies in gastric and esophageal (GE) cancer have focused on curative intent patients. This study aims to evaluate the prognostic utility of malnutrition and sarcopenia in de novo metastatic GE adenocarcinoma. METHODS: Patients with de novo metastatic GE adenocarcinoma seen at the Princess Margaret Cancer Centre from 2010 to 2016 with an available pre-treatment abdominal computed tomography (CT) were included. Malnutrition was defined as nutritional risk index (NRI) <97.5. Skeletal muscle index (SMI) was measured at the L3 level (sarcopenia defined as SMI <34.4 cm2 /m2 in women and <45.4 cm2 /m2 in men). Patients receiving chemotherapy had NRI and SMI recalculated at the time of first restaging CT. RESULTS: Of 175 consecutive patients, 33% were malnourished and 39% were sarcopenic at baseline. Patients with pretreatment malnourishment had significantly shorter overall survival (OS; 5.8 vs. 10.9 months, p = 0.000475). Patients who became malnourished during chemotherapy had worse OS compared to those who maintained their nutrition (12.2 vs. 17.5 months p = 0.0484). On univariable analysis, ECOG (p < 0.001), number of metastatic sites (p = 0.029) and NRI (p < 0.001) were significant prognostic factors while BMI (p = 0.57) and sarcopenia (p = 0.19) were not. On multivariable analysis, ECOG (p < 0.001), baseline NRI (p = 0.025), and change in NRI during treatment (p < 0.001) were significant poor prognostic factors for OS. CONCLUSIONS: In de novo metastatic GE adenocarcinoma patients, ECOG, pretreatment NRI and change in NRI were significant prognostic factors for OS while sarcopenia was not. Use of NRI at baseline and during treatment can provide useful prognostic information.

Sedated ultrasound guided saline reduction (SUR) of ileocolic intussusception: 20 year experience.

BACKGROUND: Ileocolic intussusception is a common abdominal emergency in children, diagnosed routinely with ultrasound and treated most frequently with fluoroscopic pneumatic reduction without sedation. Alternatively, ultrasound can also be used to obviate ionizing radiation and sedation can be used to avoid discomfort from the procedure. The purpose of this study was to present our experience with sedation using saline enema under ultrasound guided control to reduce ileocolic intussusception. MATERIALS AND METHODS: This is a retrospective study of patients with ileocolic intussusception presenting to a tertiary care hospital between 1998 and 2018. We excluded the data of patients that underwent either fluoroscopic guided reduction with barium enema or primary surgery. All patients received sedation with propofol and subsequently underwent our sedated ultrasound guided saline reduction (SUR) protocol until reduction was confirmed. RESULTS: 414 total reductions were performed in the 338 children who underwent our SUR protocol, of which 86.0% were successful. Zero perforations occurred during attempted reduction. 58 patients required surgery after a failed reduction (14.0%). There were 76 recurrent episodes that underwent our SUR protocol, of which 93.4% had a successful reduction. CONCLUSION: The success rate of reduction was high and compared similarly to techniques that either use pneumatic reduction under radiation or refrain from administering a sedative prior to enema. LEVEL OF EVIDENCE: Treatment study level III.

18F-DCFPyL PET/CT in Patients with Subclinical Recurrence of Prostate Cancer: Effect of Lesion Size, Smoothing Filter, and Partial-Volume Correction on PROMISE Criteria.

Our purpose was to determine the effect of a smoothing filter and partial-volume correction (PVC) on measured prostate-specific membrane antigen (PSMA) activity in small metastatic lesions and to determine the impact of these changes on molecular imaging PSMA (miPSMA) scoring. Methods: Men who had biochemical recurrence of prostate cancer with negative findings on CT and bone scintigraphy were referred for 18F-DCFPyL (2-(3-(1-carboxy-5-[(6-18F-fluoro-pyridine-3-carbonyl)-amino]-pentyl) PET/CT. Examinations were performed on 1 of 2 different brands of PET/CT scanner. All suspected tumor sites were manually contoured on coregistered CT and PET images, and each was assigned an miPSMA score as per the PROMISE criteria. The PVC factors were calculated for every lesion using the anatomic CT and then applied to the unsmoothed PET images. The miPSMA scores, with and without the corrections, were compared, and a simplified rule-of-thumb (RoT) correction factor (CF) was derived for lesions at various sizes (<4 mm, 4-7 mm, 7-9 mm, and 9-12 mm). This CF was then applied to the original dataset and the miPSMA scores that were obtained using the RoT CF were compared with those obtained using the actual corrections. Results: There were 75 men (median age, 69 y; median serum PSA, 3.69 µg/L) with 232 metastatic nodes less than 12 mm in diameter (mean lesion volume, 313.5 ± 309.6 mm3). The mean SUVmax before and after correction was 11.0 ± 9.3 and 28.5 ± 22.8, respectively (P < 0.00001). The mean CF for lesions smaller than 4 mm (n = 22), 4-7 mm (n = 140), 7-9 mm (n = 50), and 9-12 mm (n = 20) was 4 (range, 2.5-6.4), 2.8 (range, 1.6-4.9), 2.3 (range, 1.6-3.3), and 1.8 (range, 1.4-2.4), respectively. Overall, the miPSMA scores were concordant between the corrected dataset and the RoT dataset for 205 of 232 lesions (88.4%). Conclusion: A smoothing filter and PVC had a significant effect on measured PSMA activity in small nodal metastases, impacting the miPSMA score.

Impact of 18F-fluorodeoxyglucose PET/CT in the management of patients with plasma cell disorders.

OBJECTIVES: To evaluate the impact of F-fluorodeoxyglucose PET/CT examinations on the management of patients with plasma cell disorders. METHODS: This is a retrospective review of patients in a provincial database with PET/CT performed for plasma cell disorders between 2011 and 2018. The impact of PET/CT on actual patient management and outcome was assessed by two independent readers who compared planned pre-PET/CT management, documented at time of PET/CT requisition, to actual management received through linkages to administrative databases. PET/CT was considered of high impact if it altered the provision of active treatment, changed the modality of treatment or chemotherapy regimen. Change in management and the proportion of patients with high impact PET/CT were assessed. RESULTS: There were 44 patients with plasma cell disorders, including multiple myeloma, solitary plasmacytoma, Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein, Skin changes syndrome, or monoclonal gammopathy of undetermined significance or biclonal gammopathy of undetermined significance. Management was altered after 38/56 (67.9%) PET/CT scans. Considering just the initial PET/CT scan in patients who underwent multiple scans, 31/44 (70.5%) patients had their management altered subsequent to PET/CT. CONCLUSION: PET/CT resulted in a change in planned management in more than two-thirds of patients with plasma cell disorders in the current selected patient cohort. These results should be validated in a larger prospective trial.

FDG PET/CT of Mediastinal Epithelioid Hemangioendothelioma.

Epithelioid hemangioendothelioma is a rare low- to intermediate-grade malignant vascular neoplasm with a variable clinical course and currently no standardized treatment. We present a case of a 65-year-old woman diagnosed as having mediastinal epithelioid hemangioendothelioma, a location which is very exceptional. FDG PET/CT was more sensitive than CT for staging, revealing intense FDG uptake in the primary tumor and in the metastatic disease. Despite high FDG uptake, the disease was stable with no further specific treatment. Only few reports utilizing FDG PET/CT are available; review of the literature on this subject is included.

68Ga-DOTATATE PET/CT in Focal Fatty Sparing of the Liver.

Ga-DOTATATE imaging is commonly used for the detection of metastatic disease in neuroendocrine tumors. We present a case of a 69-year-old woman postsurgery for lung carcinoid tumor in which sequential follow-up Ga-DOTATATE PET/CT studies identified focal hepatic uptake that was presumed to represent a liver metastasis. However, correlative imaging with MRI revealed a focal fatty sparing of the liver composed of benign hepatic parenchyma at that area accompanied with diffuse liver steatosis in the background of the "pseudolesion." This report demonstrates a potential "false-positive" hepatic finding that can strikingly mimic a metastasis in neuroendocrine tumor imaging.

Postchemotherapy Histiocyte-Rich Pseudotumor of the Spleen Simulating Residual Disease in a Patient With Non-Hodgkin Lymphoma on FDG PET/CT.

A 64-year-old man was treated with multiagent chemotherapy owing to high-grade non-Hodgkin lymphoma presenting as a bulky disease involving the spleen. Interim and posttreatment sequential FDG PET/CT scans revealed a residual splenic mass showing markedly intense FDG uptake suspected of a residual viable lymphoma. To definitely decide about the appropriate treatment, a laparoscopic splenectomy was performed. Histopathologic specimen was compatible with the rare diagnosis of postchemotherapy histiocyte-rich pseudotumor of the spleen, a potential pitfall simulating viable disease on FDG PET/CT.

The Contribution of Multiparametric Pelvic and Whole-Body MRI to Interpretation of 18F-Fluoromethylcholine or 68Ga-HBED-CC PSMA-11 PET/CT in Patients with Biochemical Failure After Radical Prostatectomy.

Our purpose was to assess whether the addition of data from multiparametric pelvic MRI (mpMR) and whole-body MRI (wbMR) to the interpretation of 18F-fluoromethylcholine (18F-FCH) or 68Ga-HBED-CC PSMA-11 (68Ga-PSMA) PET/CT (=PET) improves the detection of local tumor recurrence or of nodal and distant metastases in patients after radical prostatectomy with biochemical failure. Methods: The current analysis was performed as part of a prospective, multicenter trial on 18F-FCH or 68Ga-PSMA PET, mpMR, and wbMR. Eligible men had an elevated level of prostate-specific antigen (PSA) (>0.2 ng/mL) and high-risk features (Gleason score > 7, PSA doubling time < 10 mo, or PSA > 1.0 ng/mL) with negative or equivocal conventional imaging results. PET was interpreted with mpMR and wbMR in consensus by 2 radiologists and compared with prospective interpretation of PET or MRI alone. Performance measures of each modality (PET, MRI, and PET/mpMR-wbMR) were compared for each radiotracer and each individual patient (for 18F-FCH, or 68Ga-PSMA for patients who had 68Ga-PSMA PET) and to a composite reference standard. Results: There were 86 patients with PET (18F-FCH [n = 76] and/or 68Ga-PSMA [n = 26]) who had mpMR and wbMR. Local tumor recurrence was detected in 20 of 76 (26.3%) on 18F-FCH PET/mpMR, versus 11 of 76 (14.5%) on 18F-FCH PET (P = 0.039), and in 11 of 26 (42.3%) on 68Ga-PSMA PET/mpMR, versus 6 of 26 (23.1%) on 68Ga-PSMA PET (P = 0.074). Per patient, PET/mpMR was more often positive for local tumor recurrence than PET (P = 0.039) or mpMR (P = 0.019). There were 20 of 86 patients (23.3%) with regional nodal metastases on both PET/wbMR and PET (P = 1.0) but only 12 of 86 (14%) on wbMR (P = 0.061). Similarly, there were more nonregional metastases detected on PET/wbMR than on PET (P = 0.683) or wbMR (P = 0.074), but these differences did not reach significance. Compared with the composite reference standard for the detection of disease beyond the prostatic fossa, PET/wbMR, PET, and wbMR had sensitivity of 50%, 50%, and 8.3%, respectively, and specificity of 97.1%, 97.1%, and 94.1%, respectively. Conclusion: Interpretation of PET/mpMR resulted in a higher detection rate for local tumor recurrence in the prostatic bed in men with biochemical failure after radical prostatectomy. However, the addition of wbMR to 18F-FCH or 68Ga-PSMA PET did not improve detection of regional or distant metastases.

18F-FDG PET/CT in Intramuscular Mantle Cell Lymphoma With Elongated Lymphomatous Neurovascular Extension.

Skeletal muscle involvement by lymphoma is rare, particularly for mantle cell lymphoma. We describe a 65-year-old man who presented with a rapidly growing left thigh mass. FDG PET/CT characterized the mass as malignant. Interestingly, an unusual hypermetabolic elongated tumorous extension was demonstrated arising from the intramuscular mass disseminating alongside the neurovascular bundle of the thigh up to the groin. Histopathology revealed intramuscular mantle cell lymphoma. In this case, we aim to highlight this interesting FDG PET/CT imaging finding, which can serve as a clue allowing one to strongly suggest lymphoma as the leading diagnosis.

Evolution of a Schmorl's Node and a Degenerative Osteophyte on Sequential 68Ga-DOTATATE PET/CT Scans: Potential Pitfalls in Neuroendocrine Tumor Imaging.

Schmorl's node (SN) arises from the herniation of the nucleus pulposus of the disc through the cartilaginous endplate into the body of the vertebra. Our report describes a patient with carcinoid tumor who underwent a series of Ga-DOTATATE PET/CT scans for follow-up, demonstrating gradually increasing focal vertebral uptake in absence of CT abnormality, suspicious for a metastasis. Both CT and MRI eventually revealed classical findings of a SN. Also observed in the same vertebra is a degenerative osteophyte showing intense Ga-DOTATATE uptake. This interesting case shows 2 benign spinal lesions, which potentially can simulate bone metastasis in patients with neuroendocrine tumors.