Phase‐sensitive inversion recovery for myocardial T₁ mapping with motion correction and parametric fitting

Abstract

The assessment of myocardial fibrosis and extra-cellular volume requires accurate estimation of myocardial T1s. While image acquisition using the Modified Look-Locker Inversion Recovery technique is clinically feasible for myocardial T1 mapping, respiratory motion can limit its applicability. Moreover, the conventional T1 fitting approach using the magnitude inversion recovery images can lead to less stable T1 estimates and increased computational cost. In this paper, we propose a novel T1 mapping scheme which is based on phase sensitive image reconstruction and the restoration of polarity of the MR signal after inversion. The motion correction is achieved by registering the reconstructed images after background phase removal. The restored signal polarity of the inversion recovery signal helps the T1 fitting resulting in an improved quality of the T1 map and reducing the computational cost. Quantitative validation on a data cohort of 45 patients proves the robustness of the proposed method against varying image contrast. Compared to the magnitude T1 fitting, the proposed phase sensitive method leads to less fluctuation in T1 estimates.

Cardiac T1 Mapping and Extracellular Volume (ECV) in clinical practice: a comprehensive review

“…Motion correction is essential for high quality T1 mapping and is generally achieved with breath holding. Image quality can be improved with respiratory motion compensation methods in patients with poor breath-holding [12] and phase sensitive inversion recovery reconstruction [13] further improved image quality. Nevertheless, residual uncorrected respiratory motion is still problematic particularly if unrecognized and in areas of thin myocardium [14].…”

Native T 1 Mapping by 3-T CMR Imaging for Characterization of Chronic Myocardial Infarctions

“…Motion-corrected native T 1 maps were constructed from the nonrigid motion-corrected pre-contrast MOLLI images as previously described (14) by the scanner's image reconstruction system. All image analyses were performed on cvi 42 (Circle Cardiovascular Imaging Inc., Calgary, Canada).…”

Synthetic late gadolinium enhancement cardiac magnetic resonance for diagnosing myocardial scar

“…The imaging parameters for the LGE were as follows: field of view 340 Â 276 mm, slice thickness 8 mm, image matrix 256 Â 156, voxel size 1.3 Â 1.3 Â 8 mm 3 , time to repetition (TR) 8.25 ms, time to echo (TE) 3.2 ms and flip angle 25 . Post contrast T1 maps were acquired using breath-hold ECG triggered Modified Look Locker Inversion Recovery (MOLLI) sequence using a shorter protocol of 4(1)3(1)2 [9] and motion correction [10]. The CMR parameters included: steady-state free precession single shot read out in end-diastole, field of view 360 Â 270 mm 2 , slice thickness 6 mm, flip angle 35…”