Three-Territory DWI Acute Infarcts: Diagnostic Value in Cancer-Associated Hypercoagulation Stroke (Trousseau Syndrome)

DWI infarcts involving the bilateral anterior and posterior circulation suggest an embolic etiology. In the absence of an identifiable embolic source, we analyzed DWI lesions involving these 3 cerebral territories to determine the diagnostic value for ischemic infarction caused by cancer-associated hypercoagulation. A retrospective analysis of all brain MR imaging studies at our institution from July 2014 to June 2015 was conducted, yielding 4075 studies. Of those, 17% ( = 709) contained the terms "restricted-diffusion" plus either "numerous," "innumerable," "multiple," or "bilateral." Of these 709 reports, 6% ( = 41) of DWI lesions involving 3 or more vascular territories of the bilateral anterior and posterior circulation were analyzed. Of the 41 patients, 19 separate etiologies were identified, the most frequent being malignancy-related infarctions (22% [ = 9]) and hypoxic-ischemic injury (12% [ = 5]). Only 2 patients had an indeterminate etiology. The most frequent etiology of infarctions not suspected clinically or radiographically was malignancy ( < .001). Infarctions of malignancy had a characteristic appearance, being nonenhancing, nonring-appearing clusters or single areas of restricted diffusion of 0.5-2 cm with a peripheral location or larger vascular territories, uncommonly in a watershed distribution, and with absence of diffuse cortical ribbon or deep gray nuclei involvement. Approximately 1 in 5 ischemic infarcts in patients with DWI lesions involving 3 vessel territories are malignancy related. In the absence of an identifiable embolic source, ischemic infarction with cancer-associated hypercoagulation accounts for 75% of cases. Cancer-associated hypercoagulation infarction should be considered, particularly when no other cause is apparent.