Introduction: Gadolinium-based contrast agents (GBCA) are necessary to enhance MRI studies. However, patients can have adverse allergic reactions. GBCA deposits in the brain[5-8] and dechelated gadolinium is toxic[1,2]. In 2006, the FDA issued a black box warning given the dose-dependent relationship between MRI contrast and the rare but serious adverse event of nephrogenic systemic fibrosis[3,4]. Patients with meningiomas require regular MRIs over decades, and the risk of contrast administration must be balanced with the need to monitor for interval tumor growth[9]. We hypothesized that non-contrast MRI sequences such as T2/FLAIR could determine growth in convexity meningiomas. Our study aims would allow us to reduce unnecessary contrast administration by demonstrating that non-contrast MRIs accurately monitor convexity meningioma growth.

Methods: This Institutional Review Board (IRB)-approved retrospective chart review included 106 MR sequences from 18 patients. Inclusion criteria were adult patients with asymptomatic convexity meningiomas who received baseline contrast-enhanced and non-contrast axial MRI imaging of the brain. Exclusion criteria included the following: 1) baseline or follow-up axial images were not available 2) baseline scan was obtained without contrast 3) the diagnosis of meningioma was later disputed. Percent tumor growth was measured by comparing cross-sectional area measured at maximum tumor diameter from the earliest and most recent scan. For each patient, change in tumor size over time was compared using T1+ contrast, T2, and T2 FLAIR sequences. These were compared to a qualitative consensus reading by a neurosurgeon and a neuroradiologist.

Results: Tumor growth of less than 10% was taken to represent stability. In 17/18 patients, noncontrast studies (T2, T2 FLAIR) accurately assessed tumor growth compared to consensus. For one patient, noncontrast studies indicated 12% growth while consensus was stability.

Conclusions: Our results suggest non-contrast MRI images may be equivalent to contrast weighted MRI images to follow change in tumor size over time in asymptomatic convexity meningiomas.

Patient Care: This research directly impacts patient care by providing an alternative to contrast-based MR studies for the long term monitoring of convexity meningiomas. This reduces patient time in the hospital, reduces the cost of management, minimizes needle sticks, and decreases the potential for allergic reactions and adverse effects of contrast such as NSF.

Learning Objectives: By the conclusion of this session, participants should be able to 1) describe the risks of long term gadolinium exposure and 2) identify alternative MR sequences for monitoring tumor growth in meningioma patients over time

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