Direct comparison of choline PET/CT and MRI in the diagnosis of lymph node metastases in patients with prostate cancer.

BACKGROUND: Lymph node detection in prostate cancer is challenging and critical to determine treatment policy. Choline PET/CT (positron emission tomography/computed tomography) and magnetic resonance imaging (MRI) have been used for the evaluation of lymph node metastasis in patients with prostate cancer for the past decade. However, only limited patients underwent direct comparison studies. PURPOSE: To evaluate the diagnostic performance of choline PET/CT compared with MRI imaging for detecting lymph node metastases in prostate cancer patients. MATERIAL AND METHODS: Relevant English-language articles published before February 2018 were searched in PubMed database, Embase database, and Cochrane Library databases search using the keywords: (Prostate Neoplasm OR Prostate Cancer OR prostate carcinoma) and (Lymph Node) and (PET/CT OR positron emission tomography/computed tomography) and (choline or 2-hydroxy-N,N,N-trimethylethanaminium) and (magnetic resonance imaging OR MRI). Articles were included that directly compare the diagnostic performance and clinical utility of choline PET/CT and MRI for detecting lymph node metastases in prostate cancer patients. Study quality was assessed with QUADAS criteria. Analyses were performed on a per patient and a per node basis. The pooled sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (LR+), and negative likelihood ratio (LR-) were calculated using Meta-Disc 1.4 software. Summary receiver-operating characteristic (SROC) curves constructed. RESULTS: A total of 362 patients from 8 studies involving fulfilled the inclusion criteria. On patient-based analysis, the pooled sensitivity, specificity, and DOR with a 95% confidence interval (CI) for choline PET/CT imaging were 0.59 (95%CI, 0.50-0.67), 0.92 (95%CI, 0.87-0.96), 17.37 (95%CI, 4.42-68.33), and for MRI imaging, they were 0.52 (95%CI, 0.44-0.61), 0.87 (95%CI, 0.81-0.92), 6.05 (95%CI, 3.09-11.85), respectively. On node-based, the corresponding values for choline PET/CT imaging were 0.51 (95%CI, 0.46-0.57), 0.99 (95%CI, 0.98-0.99), 65.55 (95%CI, 23.55-182.45), and for MRI imaging, they were 0.39 (95%CI, 0.34-0.44), 0.97 (95%CI, 0.96-0.97), 15.86 (95%CI, 8.96-28.05), respectively. CONCLUSION: Choline PET/CT performed better than MRI imaging in evaluating the lymph nodes metastasis of prostate cancer patients and had the potential to be broadly applied in clinical practice.

[Manifestations of PET/CT Imaging in Primary Central Nervous System Lymphoma].

OBJECTIVE: To investigate the PET/CT features of primary central nervous system lymphoma(PCNSL). METHODS: A retrospective analysis of PET/CT imaging manifestations and clinical data was performed in 4 PCNSL cases which were confirmed by surgery or stereotactic pathologic biopsy. RESULTS: The pathologic biopsy in 4 patients all showed diffuse large B cell lymphoma with a total of 8 lesions. All cases were performed with 18F-FDG PET/CT imaging except 1 patient simultaneously with 18F-FLT PET/CT imaging in the brain. Single lesion was found in 2 cases which both were located in the left frontal lobe. Multiple lesions were found in 2 cases, out of them 1 case located in the corpus callosum and the right lateral ventricle Angle, and the other 1 located in dual lateral ventricle and pineal region. In 18F-FDG PET/CT image, 4 patients were characterized by high metabolism, even higher than the surrounding brain tissue. The patient which underwent 18F-FLT PET/CT imaging was also presented with high metabolism and had better Target and non-target ratio(T/N). 3 cases with surrounded by edema and 2 cases with area of cystic necrosis. CONCLUSION: PCNSL are characterized by high metabolism in 18F-FDG PET/CT images and can better contrast with the surrounding normal brain. Combined use of other tracer such as 18F-FLT can improve the diagnostic value of PET/CT in PCNSL.