CNS lymphoma consists of 2 major subtypes: secondary CNS involvement by systemic lymphoma and PCNSL. Contrast-enhanced MR imaging is the method of choice for detecting CNS lymphoma. In leptomeningeal CNS lymphoma, representing two-thirds of secondary CNS lymphomas, imaging typically shows leptomeningeal, subependymal, dural, or cranial nerve enhancement. Single or multiple periventricular and/or superficial contrast-enhancing lesions are characteristic of parenchymal CNS lymphoma, representing one-third of secondary CNS lymphomas and almost 100% of PCNSLs. New CT and MR imaging techniques and metabolic imaging have demonstrated characteristic findings in CNS lymphoma, aiding in its differentiation from other CNS lesions. Advanced imaging techniques may, in the future, substantially improve the diagnostic accuracy of imaging, ultimately facilitating a noninvasive method of diagnosis. Furthermore, these imaging techniques may play a pivotal role in planning targeted therapies, prognostication, and monitoring treatment response.

Aim: To evaluate the diagnostic performance of fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for the preoperative assessment of lymph node metastases (LNM) in endometrial cancer patients and for the assessment of endometrial cancer recurrence (ECR) after primary surgical treatment. Methods: A comprehensive search was performed on Pubmed/MEDLINE databases for studies reporting the diagnostic performance of FDG-PET/CT for assessment of LNM and ECR published up to August 15th 2015. Twenty one studies (13 for LNM and 8 for ECR) were included in the systematic review and meta-analysis. Pooled estimates of sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and diagnostic odds ratio (DOR) of the FDG-PET/CT were calculated along with 95% confidence intervals (CI). A summary receiver operating characteristics curve (SROC) was constructed and the area under the SROC curve (AUC) was determined along with Q* index. Results: The overall pooled sensitivity, specificity, PLR, NLR, DOR and AUC (with 95% CI) of FDG-PET/CT for detection of LNM were 0.72 (0.63-0.80), 0.94 (0.93- 0.96), 10.9 (7.9-15.1), 0.36 (0.27-0.48), 39.7 (21.4-73.6) and 0.94 (0.85-0.99), respectively; whereas the corresponding numbers for detection of ECR were 0.95 (0.91-0.98), 0.91 (0.86-0.94), 8.8 (6.0-12.7), 0.08 (0.05-0.15), 171.7 (67.9-434.3) and 0.97 (0.95-0.98), respectively. The overall diagnostic accuracy (Q* index) in LNM and ECR were 0.88 and 0.93, respectively. Conclusion: FDG-PET/CT has an excellent diagnostic performance for detecting LNM preoperatively and disease recurrence postoperatively in endometrial cancer patients.