18F-FDG PET/CT and MRI features of myxoid liposarcomas and intramuscular myxomas.

OBJECTIVE: To examine the imaging characteristics of intramuscular myxomas (IM) and myxoid liposarcomas (MLS) on 18F-FDG PET/CT and MRI. MATERIALS AND METHODS: With IRB approval, our institutional imaging database was searched for pathologically proven IM and MLS evaluated by 18F-FDG PET/CT and MRI. PET/CT and MRI imaging characteristics were recorded and correlated with pathologic diagnosis. RESULTS: We found eight patients (2 M, 6 F) with IM (mean age 65.6 ± 10.4 years) and 16 patients (7 F, 9 M) with MLS (mean age 42.8 ± 16.3 years). MRI was available in 7/8 IM and 15/16 MLS patients. There was no significant difference between the two groups in SUVmax (IM 2.7 ± 0.8, MLS 3.0 ± 1.0; p = 0.35), SUVmean (1.7 ± 0.4, 1.5 ± 0.5; p = 0.40), total lesion glycolysis (101.8 ± 127.3, 2420.2 ± 4003.3 cm3*g/ml; p = 0.12), metabolic tumor volume (62.3 ± 71.1, 1742.9 ± 3308.0 cm3; p = 0.17) or CT attenuation (p = 0.70). MLS occurred in younger patients (p = 0.0015), were larger (16.4 ± 8.2 vs. 5.6 ± 2.5 cm; p = 0.0015), more often T1 hyperintense (p = 0.03), with nodular enhancement (p = 0.006), and macroscopic fat on CT (p = 0.0013) and MRI (p = < 0.001) compared to myxomas. CONCLUSIONS: IM and MLS most commonly demonstrate low-grade FDG activity and overlapping metabolic measures on PET/CT. MRI is useful in differentiation, but MLS can present without macroscopic fat on MRI, underscoring the importance of radiologic-pathologic correlation for accurate diagnosis.

Impact of FDG PET Standardized Uptake Value in Resected Clinical Stage IA Non-Small Cell Lung Cancer.

BACKGROUND: A significant proportion of patients with clinical stage IA non-small cell lung cancer (NSCLC) experience will recurrence and decreased survival after surgery. This study examined the impact of preoperative primary tumor positron emission tomography (PET) scan maximum standardized uptake value (SUVmax) on oncologic outcomes after surgery. METHODS: This was a retrospective review of 251 patients who underwent surgical treatment of clinical stage IA NSCLC at an academic medical center (2005-2014). Patients were classified according to PET SUVmax level (low vs high) for analysis of upstaging, tumor recurrence, and overall survival. RESULTS: Median SUVmax values were higher in squamous cell carcinoma than in adenocarcinoma (median 3.3 vs 7.2; P < .0001). There were 109 (43.4%) patients in the SUVmax low group and 142 (56.6%) in the SUVmax high group. Patients with SUVmax high had larger tumors. SUVmax high was associated with higher rates of nodal upstaging (16.2% vs 4.6% in SUVmax low; P = .004), particularly in N1 nodes. SUVmax high was independently associated with nodal upstaging (adjusted odds ratio, 3.95; 95% CI, 1.36-11.46; P = .011). SUVmax high was associated with time to recurrence (hazard ratio, 1.62; 95% CI, 1.03-2.54; P = .036), but this association was lost on multivariable analysis (hazard ratio, 1.52; 95% CI, 0.91-2.54; P = .106). SUVmax was not associated with overall survival. CONCLUSIONS: Preoperative PET SUVmax level is strongly associated with nodal upstaging, particularly in N1 nodes, in patients with clinical stage IA NSCLC who undergo resection. PET SUVmax should be regarded as a risk factor when considering candidacy for sublobar resections and in future trials involving patients with stage I NSCLC.