3T versus 1.5T phased‐array MRI in the presurgical work‐up of patients with partial epilepsy of uncertain focus

Abstract

Purpose:To study 3T compared to 1.5T phased array magnetic resonance imaging (MRI) in the presurgical work-up of patients with epilepsy with complex focus localization. Materials and Methods:In all, 37 patients (Ͼ10 years) in preoperative work-up for epilepsy surgery were offered 3T in addition to 1.5T MRI if ambiguity existed about the epileptic focus. Scans were randomly reviewed by two observers, blinded for prior imaging, patient-identifying information, and each other's assessments, followed by a consensus meeting. The number of abnormal scans, detected lesions, and interobserver agreement were calculated and compared. The final consensus was compared to original scan reports. Results:One observer identified 22 lesions in both 3 and 1.5T scans, while the second identified more lesions in 1.5T scans (28 vs. 20). 3T MRI had better interobserver agreement. 3T revealed more dysplasias, while 1.5T revealed more tissue loss and mesial temporal sclerosis (MTS). The final consensus yielded 29 lesions, whereas original reports identified only 17 lesions. Conclusion:The 3T scans revealed different lesions compared to 1.5T. Patients can benefit most from 3T scans when a dysplasia is suspected. Reevaluation by another experienced neuroradiologist is advised in case of negative or equivocal MRIs.

7TMRIin focal epilepsy with unrevealing conventional field strength imaging

“…Previous studies had compared the diagnostic yield of 3T versus 1.5T MRI in patients with focal epilepsy, reporting rates of improved lesion detection of 3T scanners ranging from 5% to 65%. [15][16][17][18][19][20] These highly variable rates were likely influenced by multiple factors, including differences in field strength, [15][16][17][18][19][20] coils used, 15,[17][18][19] expertise between reviewers, [15][16][17][18]20 use of a dedicated epilepsy protocol, [15][16][17] and clinical characteristics of patients. [15][16][17]19 Although an accurate comparison remains difficult, there seems to be no doubt that in a non-negligible percentage of patients, 3T provides additional information compared to lower field strengths.…”

“…9,10,13,14 The diagnostic yield of MRI in detecting subtle lesions is influenced by reader expertise and the accuracy with which the suspected epileptogenic zone is indicated, but it is also strongly dependent on technical considerations such as the field strength, use of phased array head coils, dedicated epilepsy MRI protocols, and novel quantitative analyses. 6,[15][16][17][18][19][20] Although applying a higher magnetic field strength could theoretically increase image resolution, the few studies comparing the diagnostic yield of 3T versus 1.5T imaging in detecting structural lesions in patients with focal epilepsy reached contradictory conclusions concerning the rates of newly detected lesions at 3T (5-65%). [15][16][17][18][19][20] So far, no comparative studies have investigated the diagnostic yield of 7T with respect to conventional MRI.…”

“…6,[15][16][17][18][19][20] Although applying a higher magnetic field strength could theoretically increase image resolution, the few studies comparing the diagnostic yield of 3T versus 1.5T imaging in detecting structural lesions in patients with focal epilepsy reached contradictory conclusions concerning the rates of newly detected lesions at 3T (5-65%). [15][16][17][18][19][20] So far, no comparative studies have investigated the diagnostic yield of 7T with respect to conventional MRI.…”

Patient’s Comfort and Technical Quality Exams at 1.5 and 3.0 T Magnetic Resonance Imaging

“…Research by Phal and associates showed that artifacts, due to displacements, were In the paper by Zijlmans and associates of the examined 27 patients, artifacts were registered in 1 patient who underwent 1.5 T MRI due to displacement and in 2 patients who underwent 3.0 T MRI, and one patient was excluded from analysis due to demonstrated artefacts at 3.0 T MRI [21]. Zijmans considers that the institutions in which the 3.0 T MRI is standard, in some cases would repeat exam at 1.5 T MRI where the artifacts in temporal and fronto-basilars regions were less demonstrated.…”

Mogućnosti detekcije i karakterizacije epileptogenih lezija primjenom magnetne rezonance jačine 1,5T i 3,0T

“…U istraživanju koje su sproveli Zijlmans i saradnici [13] pregledano je 37 pacijenata na 1,5 i 3,0T u sklopu preoperativne obrade, broj lezija identifikovanih na jačem aparatu je bio manji u odnosu na aparat sa manjom jačinom. Detaljnijom analizom dobijenih rezultata autori sugerišu prednost 3,0T u detekciji displazija dok se gubitak moždanog tkiva i temporalna mezijalna skleroza bolje prikazuje na 1,5T MR. Suštinska razlika u mogućnos-ti dijagnostikovanja temporalne hipokampalne skleroze prilikom FLAIR snimanja nije pronađena između 1,5T i 3,0T MR ni u studiji Hashiguchi i saradnika [14].…”