Is an Intravenous Injection of Gadolinium Really Necessary for Intralabyrinthine Schwannomas MR Examination?. Issue 7 (August 2018)

• Record Type: Journal Article
• Authors: Karol, Anne; Veillon, Francis; Huynh, Thaï; Severac, François; Charpiot, Anne; Venkatasamy, Aïna
• Is Part Of: Otology & neurotology. Volume 39:Issue 7(2018)
• Publication Date: 2018-08
• Subjects: Gadolinium -- Intralabyrinthine schwannomas -- Magnetic resonance imaging (MRI) -- Schwannoma -- Steady-state free precession MRI; Otology -- Periodicals; Ear -- Diseases -- Periodicals; Skull base -- Surgery -- Periodicals; 617.8005
• DOI: 10.1097/MAO.0000000000001881
• Languages: English
• ISSNs: 1531-7129

Abstract

Abstract : Objectives: Our aim was to confirm the usefulness of T2-weighted (T2W) gradient-echo sequence for detection and topographic diagnosis of intralabyrinthine schwannomas (ILS) compared with T1W contrast-enhanced sequence as gold standard, to evaluate the necessity of intravenous gadolinium injection for ILS follow-up imaging. Methods: Thirty patients with ILS were retrospectively enrolled and compared to a control group of 30 patients with no inner ear pathology. All patients underwent a T2W gradient-echo steady-state free precession (SSFP) acquisition at 3T, which was visually analyzed by two radiologists and compared to contrast-enhanced T1W sequence. A quantitative analysis was also performed, with the measurement of the tumor and inner ear signal on T2W images and the measurement of the tumor length in cochlear schwannomas. Results: T2W FIESTA-C sequence correctly diagnosed ILS with a sensitivity (Se) of 95% and a specificity (Sp) of 100%, with matching results for their topographic evaluation (Se 92%, Sp 98%) compared with the gold-standard. The difference between the two sequences was only 2.5%, with excellent interobserver agreement. The tumor signal on T2W images was significantly lower than the normal bright signal of the normal inner ear fluids (mean signal ratio = 0.42 vs 0.98). Conclusion: The positive and topographic diagnostic accuracy of T2W FIESTA-C sequence was excellent compared with the T1W contrast-enhanced sequence, even though the latter remains easier and faster to analyze for an untrained radiologist. The performances of T2W gradient-echo sequence at 3T make it a reasonable alternative strategy for following ILS after they are diagnosed.