Estimation of perfusion and arterial transit time in myocardium using free‐breathing myocardial arterial spin labeling with navigator‐echo

Abstract

Arterial spin labeling (ASL) provides noninvasive measurement of tissue blood flow, but sensitivity to motion has limited its application to imaging of myocardial blood flow. Although different cardiac phases can be synchronized using electrocardiography triggering, breath holding is generally required to minimize effects of respiratory motion during ASL scanning, which may be challenging in clinical populations. Here a freebreathing myocardial ASL technique with the potential for reliable clinical application is presented, by combining ASL with a navigator-gated, electrocardiography-triggered TrueFISP readout sequence. Dynamic myocardial perfusion signals were measured at multiple delay times that allowed simultaneous fitting of myocardial blood flow and arterial transit time. With the assist of a nonrigid motion correction program, the estimated mean myocardial blood flow was 1.00 6 0.55 mL/g/min with a mean transit time of~400 msec. The intraclass correlation coefficient of repeated scans was 0.89 with a mean within subject coefficient of variation of 22%. Perfusion response during mild to moderate stress was further measured. The capability for noninvasive, free-breathing assessment of myocardial blood flow using ASL may offer an alternative approach to first-pass perfusion MRI for clinical evaluation of patients with coronary artery disease. Magn Reson Med 64:1289-1295,

Non-contrast myocardial perfusion using a novel 4D magnetic resonance arterial spin labeling technique: Initial experience

“…Our 4D Time-SLIP technique differs from the FAIR technique in the following aspects: 1) After the non-selective pulse, we switch the selective pulse on to tag the aortic root and switch it off to serve as control, while FAIR uses a non-selective pulse to tag the whole heart and a selective pulse in the imaging as a control (Zun et al, 2009a); 2) 4D Time-SLIP uses 3D data acquisition with multiple tagging delays, and FAIR uses single slice (Zun et al, 2009a(Zun et al, , 2011Wang et al, 2010) or multiple slice 2D acquisition in general (Cambell-Washburn et al, 2013a,b);…”

“…Most recently, a non-contrast arterial spin labeling (ASL) technique, originally developed to study brain perfusion (Buxton et al, 1998;Petrella and Provenzale, 2000;Kim, 1995), has been applied to study myocardium perfusion (Zun et al, 2009a(Zun et al, ,b, 2011Wang et al, 2010;Epstein and Meyer, 2011). There are two methods of tagging blood in cardiac ASL.…”

Towards the identification of multi-parametric quantitative MRI biomarkers in lupus nephritis

“…To minimize residual motion (particularly in navigatorgated scans), a non-rigid body motion correction was applied by maximizing the cross-correlation between image frames using symmetric diffeomorphic image registration by the ANTs software [20,21]. Afterwards, all images were brought in Osirix for image quality assessment, parameter quantification and region-of-interest (ROI) analyses.…”

Arterial Spin Labeled CMR Detects Clinically Relevant Increase in Myocardial Blood Flow With Vasodilation

“…There has been preliminary work on myocardial ASL in humans (5)(6)(7)(8)(9). These preliminary studies have demonstrated the existence of an ASL signal in the heart, and while some have demonstrated signal increases with pharmacological stress, none has reported sufficient image quality and measurement consistency to provide useful diagnostic information in individual patients.…”