Acute and subacute intracerebral hemorrhages: comparison of MR imaging at 1.5 and 3.0 T--initial experience

Abstract

Purpose: To assess and describe the appearance of intracerebral hemorrhage (ICH) at 3.0-T magnetic resonance (MR) imaging as compared with the appearance of this lesion type at 1.5-T MR imaging.

Materials and methods: Sixteen patients with 21 parenchymal ICHs were examined. ICHs were classified as hyperacute, acute, early subacute, late subacute, or chronic. Patients underwent 1.5- and 3.0-T MR imaging with T2-weighted fast spin-echo, fluid-attenuated inversion-recovery (FLAIR), and T1-weighted spin-echo (1.5-T) and gradient-echo (3.0-T) sequences within 4 hours of each other. The central (ie, core) and peripheral (ie, body) parts of the ICHs were analyzed quantitatively by using contrast-to-noise ratio (CNR) calculations derived from signal intensity (SI) measurements; these values were statistically evaluated by using the Mann-Whitney U test. Two readers qualitatively determined SIs of the cores and bodies of the ICHs, degrees of apparent susceptibility artifacts, and lesion ages. The chi(2) test was used to determine statistically significant differences.

Results: With the exception of the bodies of late subacute ICHs at 3.0-T T2-weighted imaging, which had increased positive CNRs and SI scores (P </=.05), all parts of the ICHs at all stages showed increased negative CNRs and SI scores at 3.0-T FLAIR and T2-weighted imaging, as compared with these values at 1.5 T (P </=.05). No significant CNR or SI score differences at any ICH stage were observed between 1.5-T spin-echo and 3.0-T gradient-echo T1-weighted imaging (P >.05). With the exception of minor susceptibility artifacts seen in acute and early subacute ICHs at 3.0-T T1-weighted gradient-echo imaging, no susceptibility artifacts were noticed. The ages of most lesions were identified correctly without significant differences between the two field strengths (P >.05), with the exception of the ages of acute ICHs, which were occasionally misinterpreted as early subacute lesions at 3.0 T.

Conclusion: At 3.0 T, all parts of acute and early subacute ICHs had significantly increased hypointensity on FLAIR and T2-weighted MR images as compared with the SIs of these lesions at 1.5 T. However, 1.5- and 3.0-T MR images were equivalent in the determination of acute to late subacute ICHs.