Comparison of Susceptibility Weighted Imaging and Time of Flight MR Angiography in the Detection of Intra-Arterial Thrombus in Acute Ischemic Stroke Patients

Susceptibility weighted imaging (SWI) and time of flight (TOF) magnetic resonance angiography (MRA) techniques can be used in the detection of major vessel occlusion. Our aim was to compare diagnostic accuracies of SWI and TOF MRA in the detection of arterial thrombotic occlusion in acute ischemic stroke patients. In this prospective study, we included 63 consecutive patients presenting with acute ischemic stroke symptoms in whom diagnoses were based on clinical findings and diffusion-weighted imaging (DWI) studies performed within 24 hours of the onset of symptoms. The susceptibility vessel sign (SVS) and TOF MRA findings of the patients were statistically evaluated in terms of detecting acute thrombotic arterial occlusion. In  50 out of 63 patients, SVS on SWI in major intracranial artery territories and a corresponding occlusion or severe stenosis of vessels on TOF MRA were detected with a concordance. In 5 patients, although the SVS was available, TOF MRA did not reveal any occlusion or stenosis in the corresponding artery territory. On the contrary, 3 patients showed stenosis or occlusion on TOF MRA in whom SVS was negative. Finally, in the remaining 5 patients with acute infarct, neither SVS on SWI nor occlusion or stenosis on TOF MRA were displayed. SVS on SWI yielded slightly higher sensitivity than TOF MRA  in detecting intra-arterial thrombus in acute ischemic stroke patients. Although SWI and TOF MRA have similar diagnostic accuracies in the diagnosis of acute thrombotic occlusion in stroke patients, SWI has been found slightly superior to TOF MRA.