Study design

A retrospective analysis of patients with TDLs was conducted, managed at both the Royal North Shore Hospital (RNSH) and North Shore Private Hospital (NSPH) in Sydney, Australia. The study was approved by the National Health and Medical Research Council. Patients with TDL were drawn from a database of all patients with TDLs managed at the RNSH and NSPH from November 2015 to present. Patients with HGG were randomly drawn from the Sydney Neuro-Oncology Group database of gliomas treated at RNSH from 2014 to present and matched with the TDL group with respect to demographics, presentation, and MRI characteristics. Clinical, laboratory, and radiological data were retrospectively collected.

Demographic characteristics of the cohort pertain to gender and age at the time of first presentation with the cerebral lesion. Symptom type and onset were also recorded. Onset was delineated as acute (<7 days), subacute (>7 days–<3 weeks), and chronic (>3 weeks).

The MRI images were evaluated independently by two neuroradiologists, K.B and C.S.Y.N; with 4 and 5 years of experience in neuroimaging, respectively. Conventional MRI characteristics were standardized in accordance with the previous literature[8,13,22] and agreement between the two radiologists. They were defined as enhancement border (none, irregular, and regular), enhancement patterns (open, closed, and heterogeneous), mass effect: none, mild (sulcal effacement), moderate (subfalcine and uncal herniation <1 cm and/or midline shift <0.5 cm), and severe (subfalcine and uncal herniation >1 cm and/or midline shift >0.5 cm), perilesional edema: none, mild (<1 cm from the lesion), moderate (1–3 cm from the lesion), and severe (>3 cm from the lesion), size of the lesion (largest diameter), T1 intensity (hypointense, hypointense, and mixed), and T2 hypointense rim, if the lesion crosses the corpus callosum. MRI images were also evaluated for other lesions characteristic of MS neuraxis including periventricular and juxtacortical lesions and spinal cord lesions.