Non-Contrast T2-Weighted MR Sequences for Long Term Monitoring of Asymptomatic Convexity Meningiomas.

BACKGROUND: Gadolinium-based contrast agents (GBCAs) used to enhance magnetic resonance imaging (MRI) scans have been linked to tissue deposition, including in the brain. The management of indolent tumors such as meningiomas requires frequent MRI scans to monitor for interval growth. Given concern regarding GBCA deposition, we sought to determine if noncontrast MRI scans in patients with asymptomatic meningiomas were equivalent to GBCA-enhanced MRI scans in surveillance monitoring. METHODS: This institutional review hoard-approved retrospective chart review included 106 MRI sequences from 18 patients. Inclusion criteria were adult patients with asymptomatic meningiomas who received baseline contrast-enhanced and noncontrast axial brain MRI scan. Exclusion criteria included the following: 1) baseline or follow-up axial images were not available for review, 2) baseline scan was obtained without contrast, and 3) diagnosis of meningioma was uncertain. Percent tumor growth was measured by comparing cross-sectional area at maximum tumor diameter from the earliest and most recent scans. For each patient, change in tumor size over time was compared using T1 + contrast, T2, and T2 fluid-attenuated inversion recovery (FLAIR) sequences. These were compared with a qualitative consensus reading by a neurosurgeon and a neuroradiologist. RESULTS: Measured change of greater than 10% was taken to represent tumor growth. In 17 out of 18 patients, measurement of noncontrast studies (T2 and T2 FLAIR) matched consensus. For one patient, imaging on T2 suggested 11% growth, whereas T2 FLAIR and overall consensus was stability. CONCLUSIONS: Our study provides evidence that noncontrasted MRI scans are equivalent to contrast-weighted MRI scans to follow change in tumor size over time in asymptomatic meningiomas.