Susceptibility-Weighted Imaging is More Reliable Than T2*-Weighted Gradient-Recalled Echo MRI for Detecting Microbleeds

Abstract

Background and Purpose-We investigated the sensitivity and reliability of MRI susceptibility-weighted imaging (SWI) compared with routine MRI T2*-weighted gradient-recalled echo (GRE) for cerebral microbleed (CMB) detection. Methods-We used data from a prospective study of cerebral amyloid angiopathy (n=9; mean age, 71±8.3) and healthy non-cerebral amyloid angiopathy controls (n=22; mean age, 68±6.3). Three raters (labeled 1, 2, and 3) independently interpreted the GRE and SWI sequences (using the phase-filtered magnitude image) blinded to clinical information. Results-In 9 cerebral amyloid angiopathy cases, the raters identified 1146 total CMBs on GRE and 1432 CMBs on SWI.In 22 healthy control subjects, the raters identified ≥1 CMBs in 6/22 on GRE (total 9 CMBs) and 5/22 on SWI (total 19 CMBs). Among cerebral amyloid angiopathy cases, the reliability between raters for CMB counts was good for SWI (intraclass correlation coefficient, 0.87) but only moderate for GRE (intraclass correlation coefficient, 0.52). In controls, agreement on the presence or absence of CMBs in controls was moderate to good on both SWI (κ coefficient ranged from 0.57 to 0.74 across the 3 combinations of rater pairs) and GRE (κ range, 0.31 to 0.70). A review of 114 hypointensities identified as possible CMBs indicated that increased detection and reliability on SWI was related to both increased contrast and higher resolution, allowing better discrimination of CMBs from the background and better anatomic differentiation from pial vessels. Conclusions-SWI confers greater reliability as well as greater sensitivity for CMB detection compared with GRE, and should be the preferred sequence for quantifying CMB counts. (Stroke. 2013;44:2782-2786.)

The expanding phenotype of COL4A1 and COL4A2 mutations: clinical data on 13 newly identified families and a review of the literature

“…We recommend adding susceptibility-weighted imaging because it improves the detection of microbleeds. 51 Performing magnetic resonance angiography to identify cerebral aneurysms is still under debate; to date no ruptured aneurysms have been reported in mutation carriers, suggesting a slow progression rate and discouraging the use of magnetic resonance angiography. Follow-up data on the course of aneurysms identified in this specific group of patients, however, are lacking.…”

Double Inversion Recovery MR Sequence for the Detection of Subacute Subarachnoid Hemorrhage

“…[18][19][20] A recent study focusing on the detection of microbleeds also demonstrated that SWI had a greater sensitivity for blood products than the conventional T2* sequence. 21 However, no study available compares the diagnostic performance of T2* and SWI for the detection of spontaneous SAH, to our knowledge. Double inversion recovery (DIR) MR imaging is useful for the detection of cortical lesions.…”

SWI or T2*: Which MRI Sequence to Use in the Detection of Cerebral Microbleeds? The Karolinska Imaging Dementia Study

“…3 While both T2* and SWI have demonstrated good histopathologic correlation, 11-13 the use of the 2 different CMB sequences in CMB detection has complicated the comparison of results across studies. SWI has been shown to increase the number of CMBs detected, 3,14,15 and studies using the SWI sequence rather than T2* show a higher number and, in some cases, prevalence of CMBs. 14,16,17 The conventional SWI sequence has a thinner section thickness than the T2* sequence.…”

“…SWI has been shown to increase the number of CMBs detected, 3,14,15 and studies using the SWI sequence rather than T2* show a higher number and, in some cases, prevalence of CMBs. 14,16,17 The conventional SWI sequence has a thinner section thickness than the T2* sequence. A thin section thickness has been shown to increase CMB detection 15 ; thus, this might contribute to the increased CMB detection seen with SWI.…”