Delay correction for the assessment of blood-brain barrier permeability using first-pass dynamic perfusion CT

Abstract

Hemorrhagic transformation is a serious potential complication of ischemic stroke with damage to the BBB as one of the contributing mechanisms. BBB permeability measurements extracted from PCT by using the Patlak model can provide a valuable assessment of the extent of BBB damage. Unfortunately, Patlak assumptions require extended PCT acquisition, increasing the risk of motion artifacts. A necessary correction is presented for obtaining accurate BBB permeability measurements from first-pass PCT.

Fig 1.

A 75-year-old patient with a left MCA ischemic stroke. Prognostic PCT map shows a mixed pattern of infarct core (red) and penumbra (green).

Fig 2.

Absolute permeability (milliliters per 100 g per minute) maps for the reference standard 90- to 240-second delayed acquisition and for the 0- to 90-second first-pass acquisition with delay correction, the 30- to 90-second first-pass acquisition with delay correction, and the 0- to 90-second first-pass acquisition without delay correction. BBBP values calculated from the delay-corrected 30- to 90-second first-pass acquisition overlapped with the ones calculated from the reference standard 90- to 240-second delayed acquisition in the ischemic parenchymal tissue and were slightly underestimated in the nonischemic parenchymal tissue. The delay-corrected first-pass did not show the overestimation of BBBP values in the penumbra that were seen with the first-pass acquisition without delay correction.