Limitations of a Multiplicative Correction of Partial Volume Effects on the Arterial Input Function in Bolus-Tracking Perfusion

Adam Espe Hansen¹, Henrik Pedersen¹, Egill Rostrup¹, Henrik BW Larsson¹

The partial volume effect (PVE) on the arterial input function (AIF) remains a major obstacle to absolute quantification of cerebral blood flow (CBF) using MRI. This study evaluates the validity and performance of a commonly used multiplicative rescaling of the AIF to correct for the PVE. In a group of six patients, perfusion imaging was performed using a T₁-weighted approach. Various degrees of PVE were induced on the AIF and subsequently corrected using a multiplicative AIF rescaling. Our results show that a multiplicative rescaling is not always applicable and can introduce a CBF bias. An easily measurable quantity denoted the tissue signal fraction (TSF) is proposed as a measure of the applicability of a multiplicative rescaling. For the present CBF quantification method a TSF of less than 0.4 results in a CBF bias below 15% after AIF rescaling.