Diffusion-weighted magnetic resonance imaging in two patients with polycythemia rubra vera and early ischemic stroke

Polycythemia rubra vera (PRV) is a rare myeloproliferative disorder with a high risk of ischemic stroke. Although thrombosis of large cerebral arterie s is the most frequently presumed pathomechanism, various infarct patterns have been described in patients with PRV and ischemic stroke. We report two patients with mild acute ischemic strokes and known PRV, in whom a scatter ed lesion pattern was detected by diffusion-weighted magnetic resonance ima ging (DWI), but was not visible on computed tomography (CT) and conventiona l magnetic resonance imaging (MRI). Further diagnostic work-up including ex tra- and transcranial Doppler sonography (ECD, TCD), transesophageal echoca rdiography (TEE), magnetic resonance angiography and Holter monitoring reve aled no obvious sources of cerebral embolism in both cases. However, TEE in one patient demonstrated spontaneous echo contrast (SEC) in the left atriu m. In both patients the symptomatology resolved completely. The detection o f a scattered infarct pattern by DWI in patients with PRV and acute ischemi c stroke has not been reported previously. DWI findings together with the S EC in one patient emphasize the assumption that a prothrombotic state with subsequent arterial embolism rather than local arterial thrombosis may be t he underlying pathomechanism of stroke in some patients with PRV. Adding DW I to the diagnostic work-up may help to clarify etiology in patients with P RV and acute ischemic stroke.