Cardiac fludeoxyglucose-18 positron emission tomography in genotype-positive arrhythmogenic cardiomyopathy.

BACKGROUND: Myocardial inflammation contributes to the pathogenesis of arrhythmogenic cardiomyopathy (ACM), a clinically and genetically heterogenous disorder. Due to phenotypic overlap, some patients with genetic ACM may be evaluated for an underlying inflammatory cardiomyopathy. However, the cardiac fludeoxyglucose (FDG) positron emission tomography (PET) findings in ACM patients have not been elucidated. METHODS: All genotype-positive patients in the Mayo Clinic ACM registry (n = 323) who received a cardiac FDG PET were included in this study. Pertinent data were extracted from the medical record. RESULTS: Collectively, 12/323 (4%; 67% female) genotype-positive ACM patients received a cardiac PET FDG scan as part of their clinical evaluation (median age at scan 49 ± 13 years). Amongst these patients, pathogenic/likely pathogenic variants were detected in LMNA (n = 7), DSP (n = 3), FLNC (n = 1) and PLN (n = 1). Of note, 6/12 (50%) had abnormal myocardial FDG uptake, including diffuse (entire myocardium) uptake in 2/6 (33%), focal (1-2 segments) uptake in 2/6 (33%) and patchy (3+ segments) in 2/6 (33%). Median myocardial standardized uptake value ratio was 2.1. Interestingly, LMNA-positive patients accounted for 3 out of 6 (50%) positive studies (diffuse uptake in 2 and focal uptake in 1). CONCLUSION: Abnormal myocardial FDG uptake is common in genetic ACM patients undergoing cardiac FDG PET. This study further supports the role of myocardial inflammation in ACM. Further investigation is needed to determine role of FDG PET in diagnosis and management of ACM and investigate the role of inflammation in ACM.

Bayesian penalized likelihood PET reconstruction impact on quantitative metrics in diffuse large B-cell lymphoma.

Evaluate the quantitative, subjective (Deauville score [DS]) and reader agreement differences between standard ordered subset expectation maximization (OSEM) and Bayesian penalized likelihood (BPL) positron emission tomography (PET) reconstruction methods. A retrospective review of 104 F-18 fluorodeoxyglucose PET/computed tomography (CT) exams among 52 patients with diffuse large B-cell lymphoma. An unblinded radiologist moderator reviewed both BPL and OSEM PET/CT exams. Four blinded radiologists then reviewed the annotated cases to provide a visual DS for each annotated lesion. Significant (P < .001) differences in BPL and OSEM PET methods were identified with greater standard uptake value (SUV) maximum and SUV mean for BPL. The DS was altered in 25% of cases when BPL and OSEM were reviewed by the same radiologist. Interobserver DS agreement was higher for OSEM (>1 cm lesion = 0.89 and ≤1 cm lesion = 0.84) compared to BPL (>1 cm lesion = 0.85 and ≤1 cm lesion = 0.81). Among the 4 readers, average intraobserver visual DS agreement between OSEM and BPL was 0.67 for lesions >1cm and 0.4 for lesions ≤1 cm. F-18 Fluorodeoxyglucose PET/CT of diffuse large B-cell lymphoma reconstructed with BPL has higher SUV values, altered DSs and reader agreement when compared to OSEM. This report finds volumetric PET measurements such as metabolic tumor volume to be similar between BPL and OSEM PET reconstructions. Efforts such as adoption of European Association Research Ltd accreditation should be made to harmonize PET data with an aim at balancing the need for harmonization and sensitivity for lesion detection.

Predicting Outpatient Appointment Demand Using Machine Learning and Traditional Methods.

Traditional methods have long been used for clinical demand forecasting. Machine learning methods represent the next evolution in forecasting, but model choice and optimization remain challenging for achieving optimal results. To determine the best method to predict demand for outpatient appointments comparing machine learning and traditional methods, this retrospective study analyzed "appointment requests" at a major outpatient department in a destination medical center. Two separate locations (A and B) were assessed with 20 traditional, hybrid (traditional + machine learning) and machine learning methods to determine the best forecasting outcome (lowest Forecast Standard Error, FSE). Data characteristics from both datasets were examined. 20 forecasting models were then assessed and compared for the best result. Location A's data displayed a cyclical and non-trending pattern while Location B's displayed a cyclical and trending pattern. Both Location A and B yielded the feature engineered XGBoost model (machine learning) with the lowest out-of-sample FSE. It is important to carefully analyze and understand the underlying data set pattern and then test a variety of traditional, machine learning, and hybrid prediction methods to achieve optimal predictive results. Additionally, the use of feature engineering or hybrid methods can augment the usefulness of machine learning methods.

99mTc-Tilmanocept Versus 99mTc-Sulfur Colloid in Lymphoscintigraphy: Sentinel Lymph Node Identification and Patient-Reported Pain.

Lymphoscintigraphy plays a vital role in sentinel lymph node (SLN) identification in oncologic breast surgery. The effectiveness of SLN localization and the degree of patient pain were compared between filtered 99mTc-sulfur colloid (99mTc-SC) and 99mTc-tilmanocept. Methods: A retrospective review of patients undergoing lymphoscintigraphy for breast cancer using 99mTc-SC (June 1, 2010, to December 31, 2011) or 99mTc-tilmanocept (June 1, 2013, to January 31, 2014) was performed. SLN appearance time and uptake, SLN pathology, proportion of positive SLNs removed, and pain scores were compared for each radiopharmaceutical using the χ2 test, Fisher exact test, and unequal variance t test, as appropriate. Results: In total, 76 patients, with 86 evaluated axillae, underwent lymphoscintigraphy: 29 with 99mTc-SC and 47 with 99mTc-tilmanocept. The mean SLN appearance time was 11.0 min for 99mTc-SC and 19.3 min for 99mTc-tilmanocept (P = 0.003). There was no difference in the mean transit uptake percentage: 2.2% for 99mTc-SC and 1.9% for 99mTc-tilmanocept (P = 0.55). 99mTc-tilmanocept identified a greater proportion of intraoperative blue nodes than did 99mTc-SC (P = 0.03). There was no significant difference between 99mTc-SC and 99mTc-tilmanocept in the number of SLNs removed, number of patients with positive SLNs, or pain score. Conclusion: 99mTc-SC use in lymphoscintigraphy is an acceptable alternative to 99mTc-tilmanocept for SLN detection in breast cancer, on the basis of the similarity in intraoperative SLN identification and pain scores.

Prognostic significance of FDG-PET in relapsed or refractory classical Hodgkin lymphoma treated with standard salvage chemotherapy and autologous stem cell transplantation.

Positron emission tomography using [(18)F]fluorodeoxyglucose (FDG-PET) has emerged as the standard response assessment tool in frontline therapy for classical Hodgkin lymphoma (cHL). The ability of FDG-PET to predict outcomes in patients with relapsed cHL treated with modern standard salvage chemotherapy and autologous stem cell transplantation (ASCT) remains uncertain. Forty-six patients with relapsed/refractory cHL treated from 2001 to 2007 with standard salvage/ASCT therapy had FDG-PET available for blinded review. The results of pre-ASCT FDG-PET interpreted by the international harmonization project (IHP) criteria were compared with published prognostic models for prediction of event-free survival (EFS) and overall survival (OS). Overall, 3-year EFS was 62% and OS was 78%, with a median follow-up of 38 months. Pre-ASCT FDG-PET response significantly predicted 3-year EFS in FDG-PET-negative (82%) versus FDG-PET-positive (41%) patients (P = .02). A trend was observed for 3-year OS comparing FDG-PET-negative (91%) versus -positive (64%) patients (P = .08). Multivariate analysis demonstrated the independent prognostic significance of pre-ASCT FDG-PET for EFS with a hazard ratio (HR) of 3.2 (confidence interval [CI] 1.1-9.0, P = .03). Pre-ASCT FDG-PET scans predict EFS in patients with relapsed cHL patients treated with modern salvage/ASCT therapy and warrant prospective evaluation.

18F-FDG PET/CT for early response assessment in diffuse large B-cell lymphoma: poor predictive value of international harmonization project interpretation.

UNLABELLED: PET using (18)F-FDG has prognostic value when performed at the completion of initial chemotherapy in patients with diffuse large B-cell lymphoma (DLBCL). (18)F-FDG PET may also be predictive of outcome when performed during the treatment course of DLBCL, but robust prospective studies and standardization of (18)F-FDG PET interpretation in this setting are lacking. METHODS: In this prospective study, patients with advanced-stage DLBCL were treated with standard rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy, and (18)F-FDG PET/CT was performed after cycle 2 or 3 and at the end of therapy. The (18)F-FDG PET/CT scans were interpreted according to the International Harmonization Project for Response Criteria in Lymphoma, and the maximum standardized uptake value (SUV) of the most (18)F-FDG-avid lesions was recorded. RESULTS: Fifty patients were enrolled, and all underwent interim (18)F-FDG PET/CT. At a median follow-up of 33.9 mo, the positive predictive value (PPV) of interim (18)F-FDG PET/CT for relapse or progression was 42%, and the negative predictive value (NPV) was 77%. Interim (18)F-FDG PET/CT was significantly associated with event-free survival (P = 0.017) and with progression-free survival (P = 0.04) but not with overall survival (P = 0.08). End-of-therapy (18)F-FDG PET/CT had high PPV and NPV (71% and 80%, respectively) and was significantly associated with event-free survival, progression-free survival, and overall survival (P < 0.001). SUV measurements did not discriminate patients who relapsed or progressed from those who remained in remission. CONCLUSION: When performed after 2 cycles of immunochemotherapy and interpreted according to International Harmonization Project criteria, early response assessment with PET/CT has a high NPV but low PPV in patients with advanced-stage DLBCL. Prospective trials are required to validate different criteria for the interpretation of interim (18)F-FDG PET/CT and establish the role of interim (18)F-FDG PET/CT in the management of patients with DLBCL.