First-pass contrast-enhanced myocardial perfusion MRI in mice on a 3-T clinical MR scanner

Abstract

First-pass contrast-enhanced myocardial perfusion MRI in rodents has so far not been possible due to the temporal and spatial resolution requirements. We developed a new first-pass perfusion MR method for rodent imaging on a clinical 3.0-T scanner (Philips Healthcare, Best, The Netherlands) that employed 10-fold k-space and time domain undersampling with constrained image reconstruction, using temporal basis sets (k-t principle component analysis) to achieve a spatial resolution of 0.2 × 0.2 × 1.5mm(3) and an acquisition window of 43 msec. The method was successfully tested in five healthy and four infarcted mice (C57BL/6J) at heart rates of 495.1 ± 45.8 beats/min. Signal-intensity-time profiles showed a percentage myocardial signal increase of 141.3 ± 38.9% in normal mice, compared with 44.7 ± 32.4% in infarcted segments. Mean myocardial blood flow by Fermi function for constrained deconvolution in control mice was 7.3 ± 1.5 mL/g/min, comparable to published literature, with no significant differences between three myocardial segments. In infarcted segments, myocardial blood flow was significantly reduced to 1.2 ± 0.8 mL/g/min (P < 0.01). This is the first report of first-pass myocardial perfusion MR in a mouse model on a clinical 3-T MR scanner and using a k-t undersampling method. Data were acquired on a 3-T scanner, using an approach similar to clinical acquisition protocols, thus facilitating translation of imaging findings between rodent and human studies.