FIG 1. Voxels in CVTs exhibited the shortest stdTTP.

A, Conventional TTP map from an image obtained at the level of the basal ganglia by using contrast-enhanced DSC MR imaging with a T2*-weighted echo-planar fast-field-echo sequence (74/30/1; flip angle, 30°) with a 240-mm field of view, an aquisition matrix of 128 x 128 voxels, and a time resolution of 355 ms. Manual rescaling using an offset for TTP derived from the M1 segment of the left middle cerebral artery was performed to obtain an adequate perfusion map for diagnostic purposes.

B, Automatically calculated stdTTP map using the same data and scale as in panel A provides a comparable good result for TTP measurement without any loss of diagnostic information. CVTs of the anterior, middle, and posterior cerebral arteries can be differentiated as voxels with short TTP (yellow), and such voxels in BZs exhibit longer TTP (magenta and blue).