A new diffusion metric, diffusion kurtosis imaging, used in the serial examination of a patient with stroke
A 40-year-old woman complained of headache and speech disturbance without motor dysfunction for the previous two weeks. An interview revealed that she had no history of disease. Brain MRI demonstrated multiple cerebral infarctions and a more subacute infarcted lesion in the right frontal deep white matter on DWI and the calculated ADC map (Fig. a and b). A corresponding mean DK image showed the peripherally high intensity and dark dot in the stroke lesion (Fig. c). Infarction in the left temporal cortex was also observed, which was thought to be the cause of the speech dysfunction (not shown). Moreover, MR angiography poorly depicted the bilateral middle and anterior cerebral arteries (not shown). The patient was ultimately diagnosed with Moyamoya disease. Two weeks later, repeated MR scanning revealed a homogenous high signal on both DWI and the ADC map (Fig. d and e) and partially normalized mean DK (Fig. f) in the corresponding ischemic lesion. In the FLAIR image taken 6 months later (Fig. g), the stroke lesion displayed a low signal in the central cystic portion with peripheral high intensity, as reflected in the DK image.