RESUMEN
The purpose of this study was to investigate the appearance of Paget's disease (PD) on 11C choline PET/CT and correlate these findings to serum alkaline phosphatase (ALP) level and skeletal scintigraphy. With IRB approval, our institutional 11C choline PET/CT database (9/2005-6/2015) was searched for patients with PD. Site of osseous involvement, CT appearance, and multiple semi-quantitative measures were measured and correlated with ALP and degree of uptake on bone scan. Our search identified 10 males (mean age 79.6 ± 7.8 years). Four had polyostotic disease and seven had more than one 11C choline PET/CT. In total, 58 affected bones were evaluated on 25 PET/CTs. Mean lesion SUVmax was 2.6 ± 0.89 (range 1.0-4.4), SUVmax/Liver SUVmean 0.33 ± 0.13 (0.12-0.61), SUVmax/Liver SUVmax 0.29 ± 0.11 (0.10-0.52), SUVmax/BP SUVmean 2.47 ± 0.86 (0.91-4.22), and SUVmax/BP SUVmax 1.92 ± 0.71 (0.68-3.45). There was no correlation between ALP and any semiquantitative measure. Bone scan uptake was marked in 41 bones, moderate in nine, and mild in six. There was no correlation between lesion SUVmax and bone scan uptake (P = 0.26). Paget's disease on 11C choline PET/CT demonstrates mild to moderate activity, which does not correlate with bone scan uptake or ALP level. It is important to recognize Paget's disease as a potential pitfall on 11C choline PET/CT. However, the characteristic appearance on the CT portion of PET/CT examinations should allow confident diagnosis and differentiation from prostate cancer osseous metastases.
RESUMEN
PURPOSE: To compare MR hepatic fractional extracellular space (fECS) to liver stiffness (LS) with magnetic resonance elastography (MRE) for evaluation of liver fibrosis. METHODS AND MATERIALS: 71 consecutive patients with suspected chronic liver disease underwent standard liver MRI with MR elastography and additional delayed Gd-DTPA-enhanced sequences at 5 and 10 min in order to calculate hepatic fECS (%) and LS (kilopascals, kPa). Two radiologists blinded to clinical history examined MR images and calculated fECS and LS in identical locations for every patient. Interobserver agreement was calculated using the intraclass correlation coefficient. Pearson's correlation was calculated for LS and fECS measures, as was the area under the receiver operatic curve (AUROC), sensitivity and specificity of fECS to predict liver stiffness ≥2.93 and ≥5 kPa. The sensitivity of fECS for detecting fibrosis was separately analyzed in the subgroup of patients without anatomic findings of cirrhosis. RESULTS: Substantial to excellent interobserver agreement for both LS and fECS measurements was seen with intraclass correlation of 0.88 (95% CI 0.81-0.92) for LS, 0.77 (95% CI 0.66-0.85) for fECS5 and 0.76 (95% CI 0.64-0.84) for fECS10. A significant correlation was found between MRE and fECS5 (r = 0.47, p < 0.0001) and fECS10 (r = 0.44, p < 0.0001). The performance of fECS improved for detection of advanced fibrosis (≥5 kPa) with AUROC, sensitivity and specificity of 0.72, 38%, and 94% for fECS5 and 0.72, 67%, and 66% for fECS10. CONCLUSION: fECS correlates modestly with MRE-determined LS. fECS at MRI is a simple calculation to perform and may represent a practical way to suggest the presence of fibrosis during routine liver evaluation.