Background: Embolic ischemic strokes are commonly considered to be cardiogenic. In clinical practice, however,patients with a pattern of multiple tiny ischemic foci on MRI often have no cardiac source. To identifying its etiology may help selecting the right therapy to treat or prevent recurrent strokes.
Methods: From 1/2010 to 12/2013, records and MRI imaging of 2984 consecutive stroke patients were reviewed. Patients with the following DWI MRI findings were included: 1) ≥3 high intensity lesions in three different arterial territories, 2) each ≤15mm in size and ≤2 sections in thickness. Other data reviewed include general demographics, clinical features and lab results. Patients with known cardiac embolism, aortic arch plaques or aneurysms and recent surgery were excluded. Images of follow-up MRI were reviewed.
Results: Among 2984 cases reviewed, 71 patients had multiple tiny DWI lesions. In order to rule out artery to artery emboli, patients with lesions from the same artery territory or watershed region were excluded. Only 43 met all criteria. Their median age was 65 and 23(53.5%) were male. Extremity weakness and slurred speech were the most common presenting symptoms. The median number of DWI lesions in each brain was 13. Common disorders identified include: infection (81.4%), hyperlipidemia(58.1%), moderate chronic kidney disease(39.5%), previous history of stroke (48.8%). Four (9.3%) had large B cell lymphoma and 2 had lung cancer. The quantity of DWI lesions was related to hyperglycemia, hyperlipidemia and impaired GFR. Patients with primary hypercoagulable state more likely had multiple lesions (median 39). On discharge, 5 (11.6%) patients were prescribed dual antiplatelet therapy and 11 (25.6%) were given oral anticoagulants.
Conclusions: To our knowledge, this was the first review of this type of specific DWI findings with clinical correlation. Multiple tiny or ‘Star-like’ type of lesions on DWI MRI were likely caused by infection, hyperlipidemia CKD and leukemia. They are unlikely cardiogenic and its recurrent rate was high. Recognizing the pattern of these tiny lesions will help clinicians refocus on the work up of stroke, strategies of treatment and stroke prevention strategy.