Routine Administration of Contrast Is Not Required for Surveillance of Treated and Untreated Meningiomas

Introduction: Patients diagnosed with meningiomas routinely undergo contrast enhanced magnetic resonance imaging (MRI) for serial assessment of tumor size and growth. Contrast administration increases resource utilization and risk; including preparation, scanning and interpretation time and cannulation of the patient. The long-term consequences of gadolinium accumulation are as yet unknown. We hypothesized that treated and untreated meningiomas could be adequately monitored using unenhanced MRI.

Methods: We retrospectively identified 136 adult patients (99 female, 37 male) with treated (47.8%) and untreated (52.2%) meningiomas who had two MRI scans with contrast enhanced T1 (T1+C) and T2 weighted sequences (T2) at least 6 months apart (average 20.5, range 6-76). Two radiologists reviewed scans for each sequence separately and assessed tumor location, dimensions, growth, venous invasion and edema. The agreement between growth and venous invasion assessed on T2 and that assessed on T1+C or T2 was evaluated with Cohen’s kappa test. Intra-rater reliability between T2 and T1+C measurements of tumor dimension was calculated for each observer.

Results: Growth assessed on T2 showed excellent agreement with growth assessed when both sequences were available (K = 0.945), with 100% specificity, 92.3% sensitivity and 97.8% accuracy. There was substantial agreement between venous invasion on T2 and venous invasion on both sequences (K = 0.771). There was substantial intra-rater agreement between T2 and T1+C measurements of anteroposterior and transverse tumor dimensions (all calculated ICC values >0.883 for Observer 1, >0.767 for Observer 2). Inter-rater agreement between the observers for tumor dimensions measured on both sequences was substantial (all calculated ICC values >0.843). Subgroup analysis for skull base (58.1%) and treated (47.8%) meningiomas did not show any significant difference in agreement between T2 only and T1+C and T2 assessments of growth and venous invasion.

Conclusion : T2 weighted imaging can be used for radiological surveillance of treated and untreated meningiomas without additional contrast enhanced sequences.