Comparison of susceptibility-weighted and perfusion-weighted magnetic resonance imaging in the detection of penumbra in acute ischemic stroke.

BACKGROUND AND PURPOSE

To investigate detection of ischemic penumbra in stroke patients with acute cerebral infarction by susceptibility-weighted imaging (SWI) in comparison with perfusion-weighted imaging (PWI).

MATERIALS AND METHODS

This study included 18 stroke patients with acute infarction who underwent diffusion-weighted imaging (DWI), SWI, PWI, and magnetic resonance angiography (MRA) within 3 days after symptom onset. The Alberta Stroke Program Early CT Score (ASPECTS) was used to evaluate lesions on DWI, SWI, and PWI. DWI-SWI and DWI-PWI mismatches were calculated.

RESULTS

The DWI-SWI mismatch was not significantly different from the DWI-mean transit time (MTT) mismatch (P=0.163) in evaluating ischemic penumbra. The susceptibility vessel sign (SVS) in SWI occurred in 11 (61%) of 18 patients with cerebral infarction. Stenosis or occlusion of the affected vessels was identified by MRA in 10 (91%) of the 11 SVS-positive patients. The SVS on SWI was significantly associated with the occurrence of damaged vessels or the presence of thrombus in the affected vessels (P=0.047).

CONCLUSIONS

DWI-SWI mismatch is a good marker for evaluating ischemic penumbra in stroke patients with cerebral infarction. SWI can detect thrombus in the affected vessels, and may be useful for guiding intra-arterial thrombolytic therapy.