Primary central nervous system lymphoma (PCNSL) is an uncommon but important variant of non-Hodgkin lymphoma and represents up to 6% of all primary central nervous system (CNS) malignancies. Recognition of this entity by radiologist on MRI may avoid unnecessary neurosurgical resection and redirect to biopsy. The pretreatment MRI of patients with biopsy proven PCNSL from the last 5 years at our institution was reviewed. Selected examples were used to construct a pictorial essay to illustrate some of the typical and atypical MR features of PCNSL. MRI of other CNS conditions with imaging similarities to PCNSL was included to demonstrate possible mimics. The typical features of PCNSL lymphoma are intra-axial homogenous single or multiple contrast enhancing lesions, with marked surrounding oedema and restricted diffusion, usually contacting a cerebrospinal fluid (CSF) surface. Necrosis, peripheral enhancement, haemorrhage or calcification are unusual and other diagnoses should be considered if any of these features are present. Potential mimics include high grade glioma, infarcts, metastatic disease, demyelination, abscess and secondary lymphoma. Careful assessment of the MR features and correlation with the clinical findings should enable the radiologists to raise the possibility of PCNSL and minimise the risk of unnecessary resection.

Combined proximal descending aortic endografting plus distal bare metal stenting for aortic dissection provides favorable short-term outcomes and decreases late distal aortic complications compared with conventional endovascular repair. These results support a more widespread application of this approach. A prospective, randomized trial is needed before definite conclusions can be made.

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Purpose Prostate speci c membrane antigen (PSMA) PET/CT is increasingly used in men with biochemical recurrence post-prostatectomy to detect local recurrence and metastatic disease at low PSA levels. The aim of this study was to assess patterns of disease detection, predictive factors and safety using 18 F-DCFPyL PET/CT versus diagnostic CT in men being considered for salvage radiotherapy with biochemical recurrence post-prostatectomy.Methods We conducted a prospective trial recruiting 100 patients with biochemical failure postprostatectomy (PSA 0.2-2.0ng/mL) in men referred for salvage radiotherapy from August 2018 to July 2020. All patients underwent a PSMA PET/CT using the 18 F-DCFPyL tracer and a diagnostic CT. The detection rates of 18 F-DCFPyL PET/CT vs diagnostic CT were compared and patterns of disease are reported. Clinical patient and tumour characteristics were analysed for predictive utility. Thirty-day postscan safety is reported.Results Of 100 patients recruited, 98 were suitable for analysis with a median PSA of 0.32ng/mL. 18 F-DCFPyL PET/CT was positive or equivocal in 52% compared to 19.6% for diagnostic CT. Local recurrence was detected on 18 F-DCFPyL PET/CT in 29.2%, nodal disease was seen in 29.6% and bony metastases in 7.1%. Both ISUP grade group (p = 0.003) and pre-scan PSA (p = 0.061) were signi cant predictors of 18 F-DCFPyL PET/CT positivity, and logistic regression generated probabilities combining the two showed improved prediction rates. No signi cant safety events were reported post 18 F-DCFPyL administration.Conclusions 18 F-DCFPyL PET/CT increases detection of disease in men with biochemical recurrence post-prostatectomy compared to diagnostic CT. Men being considered for salvage radiotherapy with a PSA > 0.2ng/mL should be considered for 18 F-DCFPyL PET/CT scan.