Abstract TP85: The Characteristics of Diffusion Weighted Image Patterns in Different Potential Embolic Source

Abstract

Introduction: Few studies have focused on the characteristics of diffusion weighted image (DWI) pattern in different embolic stroke. Hypothesis: Studying the DWI pattern in patients with embolic stroke of determined source may help presume the cause of ESUS. Methods: From a prospective registry of 1,764 consecutive patients with acute ischemic strokes , we selected 422 patients with embolic stroke of determined source comprising of 4 groups as follows. 1: continuous atrial fibrillation (cAf) (n=232), 2: paroxysmal Af (pAf) (n=99), 3: paradoxical embolism associated with the foramen ovale (PXE) (n=48) and 4: aortogenic embolism associated with aortic atheroma (≥4mm, ulcer or mobile) (AoE) (n=56). The DWI patterns were classified as follows. First, cortical infarcts were classified according to the affected area of middle cerebral artery (MCA) segments such as M1: the horizontal segment, M2: after the bifurcation segments within the Sylvian fissure and M4: terminal cortical branch. Among patients with M1, pure striatocapsular infarction (SCI) was identified. Moreover, patients with the M2 and the M4 were divided into 2 groups including parietal ascending branches and temporal descending branches. Second, cortical and subcortical small multiple infarcts (<20mm) (sMI) were identified. Finally, infarcts in the anterior cerebral artery (AC) and the posterior circulation (PC) were identified. Results: The distribution of the DWI patterns in the 4 groups (cAf: pAf: PXE: AoE, %) are as follows: M1 (n=100) (76.0: 17.0: 7.0: 0), M2 (n=118) (59.3: 30.5: 7.6: 2.5), M4 (n=50) (50.0: 26.0: 18.0: 6.0), SCI (n=20) (2.1: 4.0: 14.5: 0), sMI (n=49) (18.3: 16.3: 18.3: 46.9), AC (n=13) (46.1: 46.1: 0: 7.6), and PC (n=92) (50.0: 20.6: 15.2: 14.1). Among 162 patients with M2 and M4 infarction, there were 57 involvements of descending branches (35.1%), comprising of 38 patients (41.7%) in cAf, 17 (34.6) in pAf, 1 (6.2) in PXE and 1(7.4) in AoE. Conclusions: Infarct sized was large in the Af groups. The involvement of inferior division of the MCA was exclusively found in the Af groups. The SCI was most prevalent in the PX. Multiple small scattered pattern was characteristically found in the AoE. The different DWI patterns relatively well associated with different embolic source.