Quantitative myocardial perfusion

Quantifying cardiac perfusion with MR is an increasingly popular method to diagnose myocardial ischemia and assess myocardial disease. While the feasibility of 2D cardiac perfusion has been established, the increased coverage and slice resolution of 3D methods aid in identifying subendocardial ischemia, increase confidence that any defects have been identified, may improve estimation of ischemic burden, offer improved handling of respiratory motion and reduce dark rim artifacts. Despite these advantages, reduced clinical utility of 3D methods has been historically observed. We have designed a 3D stack-of-stars sequence to achieve a 150ms readout time suitable for both stress and rest quantitative perfusion with an efficiently measured arterial input function.

perfusion
Figure 1: Standard and efficient methods of acquiring an AIF. For the standard method on top (a), the AIF (yellow slice) is measured at the center of the 3D volume (blue volume) and consequently must be applied before or after the entire 3D acquisition including its non-selective saturation pulse (NS-Sat) and SRT delay. In the efficient method on the bottom (b), the AIF is acquired basal to the 3D volume and shares the saturation pulse of the 3D volume.
perfusion 3D
Figure 2: Quantitative 3D perfusion source images at the beginning of myocardial enhancement. Shown are all 8 slices in systole for a 31 year old female volunteer (a) and a 63 year old male subject with quadruple bypass surgery (c) and a known infarct (red arrow). The arterial input function along with tissue uptake curves are shown in (b) and (d) for one mid ventricular slice in both these subjects.