Background:
Red thrombi, composed of fibrin and trapped erythrocytes, have magnetic susceptibility effect. Susceptibility vessel sign (SVS) is visualized more sensitively using susceptibility weighted imaging (SWI) than T2*-weighted imaging. Bright vessel appearance (BVA) on arterial spin labeling (ASL) imaging can visualize occluded arterial segment by arterial transit artifact, more sensitively in small and peripheral branches. We investigated the usefulness of SWI-SVS with BVA to visualize different thrombus and predict stroke mechanisms.
Methods:
From a total of 564 stroke cases who admitted to Seoul National University Hospital in 2014, the authors collected eligible cases with the following inclusion criteria; (1) Lesion-documented ischemic stroke (N=425); (2) SWI and ASL MRI performed (N=407); (3) Symptomatic arterial occlusion with BVA (N=141). All images were analyzed for the presence and location of SWI-SVS and BVA. The location of SWI-SVS and BVA were classified into (1) proximal, large arteries; distal ICA, M1/2, A1, P1, basilar artery, V4 and (2) peripheral, small arteries; M3/4, P2/3, A2/3, lenticulostriate arteries, three cerebellar arteries. The relationships between SWI-SVS in the presence of BVA and stroke etiologies are explored.
Results:
Male was 58.2% (n=82) and mean age was 65.7±14.3. Thirty-four percent (n=48/141) of BVA and 30.3% (n=30/99) of SVS was located within small, peripheral arteries. SWI-SVS was more commonly associated with other determined etiology (20.2% vs. 4.8%) and cardioembolism (39.4% vs. 14.3%), but less with large artery atherosclerosis (26.3% vs. 69.0%, P <0.01) compared to the patients without SWI-SVS. Cancer-related hypercoagulability (60%, n=12/20) was most common in other determined cases with SWI-SVS. Multivariate analysis showed that SWI-SVS was an independent predictor of other determined etiology (adjusted OR, 7.20; 95% CI, 1.48-34.99) and cardioembolism (adjusted OR, 5.76; 95% CI, 1.27-26.02)
Conclusions:
SWI-SVS with BVA may predict ischemic stroke of cardioembolism and other determined etiology. Occlusions of small, peripheral arteries are well visualized with BVA and composition of thrombus can be identified by SWI-SVS.
Screening for early detection of lung cancer: results from Seoul National University Hospital.
