Extent of Myocardial Ischemia on Positron Emission Tomography and Survival Benefit With Early Revascularization.

BACKGROUND: Prior studies with single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) have shown a survival benefit with early revascularization in patients with >10% to 12.5% ischemic myocardium. The relationship among positron emission tomography (PET)-derived extent of ischemia, early revascularization, and survival is unknown. OBJECTIVES: The purpose of this study was to evaluate the association among percent ischemia on PET MPI, revascularization, and survival. METHODS: A total of 16,029 unique consecutive patients who were undergoing Rubidium-82 rest-stress PET MPI from 2010 to 2016 were included. Patients with known cardiomyopathy and nondiagnostic perfusion results were excluded. Percent ischemic myocardium was estimated from a 17-segment model. Propensity scoring was used to account for nonrandomized referral to early revascularization (90 days of PET). A Cox model was developed, adjusting for propensity scores for early revascularization and percent ischemia, and an interaction between ischemia and early revascularization was tested. RESULTS: Median follow-up was 3.7 years. Overall, 1,277 (8%) patients underwent early revascularization and 2,493 (15.6%) died (738 cardiac). Nearly 37% of patients (n = 5,902) had ischemia, with 13.5% (n = 2,160) having ≥10%. In propensity-adjusted analyses, there was a significant interaction between ischemia and early revascularization (p < 0.001 for all-cause and cardiac death), such that patients with greater ischemia had improved survival with early revascularization, with a potential ischemia threshold at 5% (upper limit 95% confidence interval at 10%). There was no differential association between ischemia and early revascularization on death based on history of known coronary artery disease (interaction p = 0.72). CONCLUSIONS: In a contemporary cohort of patients undergoing PET MPI, patients with greater ischemia had a survival benefit from early revascularization. On exploratory analyses, this threshold was lower than that previously reported for SPECT. These findings require future validation in prospective cohorts or trials.

Prognostic and Predictive Values of Metabolic Parameters of 18F-FDG PET/CT in Patients With Non-Small Cell Lung Cancer Treated With Chemotherapy.

OBJECTIVES: Increasing interests have been focused on using artificial intelligence (AI) to extend prognostic value of medical imaging. Feature extraction is a critical step for successful application of AI. The aim of this study was to explore several metabolic parameters measured by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) as potential AI features in predicting the effectiveness of chemotherapy in patients with non-small cell lung cancer (NSCLC). METHODS: A set of metabolic parameters of PET/CT and clinical characteristics were detected from 137 patients with NSCLC treated with at least 1 cycle of chemotherapy. Survival receiver-operating characteristic (ROC) analysis was used to define the more significant parameters chosen for the following survival analysis. Patient survival was analyzed by Kaplan-Meier method, log-rank test, and Cox regression. RESULTS: Survival ROC showed that maximum standardized uptake value (SUVmax), metabolic tumor volume 50% (MTV50), and total lesion glycolysis 50% (TLG50) had larger area under the curve, and the optimal cutoff values were 11.72, 4.04, and 34.55, respectively. Univariate and multivariate analyses synergistically showed that late PET/CT stage and MTV50 >4.04 were independent factors of poor survival in patients with NSCLC who received chemotherapy. CONCLUSIONS: Several potential prognostic biomarkers of PET/CT imaging have been extracted for predicting survival and selecting patients with NSCLC who are more likely to benefit from chemotherapy. The identification may accelerate the development of AI methods to improve treatment outcome for NSCLC.

The prognostic value of SUVmax measuring on primary lesion and ALN by 18F-FDG PET or PET/CT in patients with breast cancer.

PURPOSE: To evaluate the prognostic value of maximum standardized uptake values (SUVmax) measured in the primary lesion and axillary lymph nodes (ALN) by pretreatment fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) in patients with breast cancer. METHODS: We systematically searched PubMed, Embase, and the Cochrane Library. The primary prognosis endpoint was event-free survival (EFS), and the secondary endpoint was overall survival (OS). The pooled hazard ratio (HR) was estimated by using random-effects model according to the results of heterogeneity. RESULTS: Fifteen eligible studies with 3574 breast cancer patients were included. For EFS, patients with higher primary SUVmax showed a poorer survival prognosis with pooled HR of 1.96 (95% confidence interval (CI) 1.40-2.73). The combined HR of high SUVmax in ALN and ALN-to-primary SUVmax ratio (N/T ratio) were 1.89 (95% CI 0.70-5.07) and 2.06 (95% CI 0.59-7.21), respectively. In analyzing invasive ductal carcinoma (IDC) patients, the pooled HR was 1.91 (95% CI 1.40-2.64). For OS, the pooled HR of SUVmax in primary lesion and ALN were 0.64 (95% CI 0.23-1.84) and 1.09 (95% CI 0.07-16.53), respectively. CONCLUSIONS: Our meta-analysis suggested that patients with high primary SUVmax may experience a higher risk for recurrence or a poor progression. Moreover, the SUVmax of 18F-FDG showed a significant prognostic value in IDC patients.

Tumor thrombus in the large veins draining primary pelvic osteosarcoma on cross sectional imaging.

PURPOSE: To evaluate the frequency of tumor thrombus in the large veins draining primary pelvic osteosarcoma on early cross-sectional imaging studies and its effect on patient survival. MATERIALS AND METHODS: Our retrospective study included all patients with primary pelvic osteosarcoma treated at our facility between January 2000 and May 2014, who were ≤ 45 years of age, and had adequate imaging studies and clinical follow up. Four radiologists evaluated for tumor in the large draining veins on initial CT, MRI and PET/CTs. A consensus evaluation by the four radiologists together with findings on operative reports, pathology reports or follow-up imaging was used as the reference standard. RESULTS: Thirty-nine patients with primary pelvic osteosarcoma met final inclusion criteria. Tumor thrombus was identified in the large draining veins in 10 of the 22 (45%) patients who underwent tumor resection and 10 of the 17 (59%) who did not. In the 22 patients who underwent tumor resection, tumor thrombus was significantly associated with worse overall survival (p = 0.03). CONCLUSIONS: Tumor thrombus in the large draining veins is identified in a significant proportion of initial imaging studies in patients with pelvic osteosarcoma, and is associated with worse overall survival in patients who undergo tumor resection.

Prognostic value of interim fluorodeoxyglucose and fluorothymidine PET/CT in diffuse large B-cell lymphoma.

OBJECTIVE:: To examine the prognostic value of fluorodeoxyglucose (FDG) and fluorothymidine (FLT) interim positron emission tomography/CT (PET/CT) for diffuse large B-cell lymphoma (DLBCL). METHODS:: 44 patients with newly diagnosed DLBCL underwent both fluorine 18 FDG (18F-FDG) and 18F-FLT PET/CT scans at baseline and after two cycles of a rituximab-containing chemotherapy regimen. Maximum standard uptake values (SUVmax) and changes in SUV (ΔSUV) were calculated for both tracers for the predominant lesion of each patient, for prediction of progression-free survival (PFS) and overall survival (OS). RESULTS:: The median follow-up period was 71 months. Receiver operating characteristic (ROC) analysis indicated that the best ΔSUV cut-off values for FDG (ΔSUVFDG) and FLT (ΔSUVFLT) were 79 and 76%, respectively. A ΔSUVFLT cut-off of 76% had the highest significance for prediction of PFS (p = 0.003) and OS (p = 0009), with sensitivity, specificity, and accuracy of 80.0, 85.7, and 81.8% respectively in response assessment. CONCLUSION:: Interim FLT PET/CT had higher specificity and accuracy than standard FDG PET/CT-based interpretation. ADVANCES IN KNOWLEDGE:: This study demonstrated that interim FLT PET/CT had higher accuracy than standardized FDG-based interpretation for therapeutic response assessment in DLBCL. FLT had the advantage of potentially reducing false positive of interim FDG PET/CT.