Comparison of MRI Sequences to CT in Identification of Calcified Subependymal Nodules in Tuberous Sclerosis Patients (P03.134)

Abstract

Objective: To determine if MRI is as effective as CT in identification of calcified subependymal nodules in tuberous sclerosis (TS) patients, so that the number of CT scans that TS patients undergo may be able to be reduced, leading to less radiation exposure and less cost. Background CT has been used to look for calcifications in TS patients, especially if they have enlarging subependymal nodules concerning for subependymal giant cell astrocytomas. However, CT has been found to be a source of significant radiation, and MRI techniques have advanced. Design/Methods: TS patients who underwent both a CT and MRI within a 120 day period were evaluated. CT and MR studies from the same patient were compared. CT was considered the gold standard in identification of calcification. Calcification on CT was considered a true positive (TP). Results: Neuroimaging from 9 patients has been reviewed. Patient ages ranged from 2 months to 7 7/12 years, with an average of 3.9 years. Only 2 patients had SWI sequences, which was a limitation of this study. Fifty-five subependymal nodules were identified. MRI overall detected 52 of 55 lesions. The sensitivity for detecting subependymal nodules was 94.5% for T2-weighted imaging, 85% for B0 sequences, and 87% for SWI. The overall sensitivity of CT for detecting subenpendymal nodules was 94.5%; however, most of the lesions were calcified. The sensitivity of CT for uncalcified subependymal nodules was 25%. Among the MRI sequences, the sensitivity for detecting calcifications on T2-weighted sequences was 78%, B0 sequences was 82%, and SWI was 87%. Conclusions: CT is more sensitive than MRI at detecting calcified subependymal nodules. However, it is not sensitive for uncalcified nodules. Traditional MRI (without SWI) tended to underestimate calcified subependymal nodules. However, addition of SWI, which appeared to be the most sensitive MRI sequence to calcification, may allow closer approximation to CT findings. Disclosure: Dr. McGregor has received royalty payments from MedHumor Publishing. Dr. Caron has nothing to disclose. Dr. Perkins has nothing to disclose. Dr. Wheless has received personal compensation for activities with Abbott, UCB, GSK, Novartis, Ortho-McNeil, Cyberonics, Abbott, Cyberonics, Inc., Novartis, Ovation Pharmaceuticals, Marinus Pharmaceuticals, Questcor, Valeant, Pfizer Inc as a consultant and/or participant on an advisory board. Dr. Wheless has received research support from Abbott Laboratories, Cyberonics, Inc., Ortho-McNeil Pharmaceuticals, Novartis, UCB Pharma and Ovation Pharmaceauticals. Dr. Choudhri has nothing to disclose.