Work

Improved late gadolinium enhancement imaging of left ventricle with isotropic spatial resolution

Year: 2012

Type: article

Abstract: Recent studies have shown the prognostic value of the infarct border zone of late gadolinium enhancement (LGE) images in patients with myocardial infarction [ 1 ]. This border zone has also been associated with ventricular arrhythmia [ 2 , 3 ]. The accuracy of the characterization of this area depends on spatial resolution of the imaging. 3D LGE allows improved spatial resolution, especially in through-plane direction. However imaging with an isotropic spatial resolution necessitates very long scan time. In this study, we sought to investigate if compressed-sensing (CS) based image acceleration method [ 4 ] allows LGE imaging with isotropic spatial resolution. A prospective random under-sampling LGE acquisition was implemented on 1.5T Philips scanner. A free-breathing ECG-triggered inversion-recovery GRE sequence with navigator-gating was used for all acquisitions on 18 patients (5 females, 52.8±16.3 years) 10 to 20 minutes after bolus infusion of contrast agent. Each subject were imaged using two LGE sequence in random order: a) a 3-fold-accelerated LGE scan with isotropic spatial resolution of 1.2-to-1.7 mm , b) LGE scan with non-isotropic resolution of 1.7×1.7×4.0mm were performed with imaging parameters of TR/TE/α=5.2/2.6ms/25°, FOV=320×320×100mm . Random undersampling was implemented as described in [ 5 ], where the central k-space (45×35 in ky-kz) was fully-sampled. Acquisition times were 3 mins assuming 100% scan efficiency at 70 bpm for both scans. The images from the accelerated scans were reconstructed using an advanced CS-technique, called LOST [ 4 ]. Figure 1 shows LGE images from a patient with hypertrophic cardiomyopathy acquired using two different approaches. An improved isotropic spatial resolution allows better characterization of the scar morphology. Figure 2 shows another example in a patient undergoing ICD implantation as a primary prevention of sudden cardiac death. Reformatted LGE images from a patient with HCM, acquired using non-isotropic spatial resolution (top), and isotropic spatial resolution (bottom). An isotropic resolution allows better visualization of scar morphology in images acquired using LOST-accelerated acquisition. Axial (left) and reformatted long-axis (right) LGE images from a patient. Non-isotropic LGE was acquired with a spatial resolution 1.7×1.7×4.0 mm (top), whereas LOST-reconstructed isotropic resolution images from the accelerated scan had a resolution of 1.2×1.2×1.2 mm (bottom). Accelerated LGE imaging with isotropic spatial resolution allows improved visualization of scar morphology. Further quantitative measurements of infarct border zones in a larger cohort of patients are needed to better understand the prognostic value of the improved scar imaging.

Source: Journal of Cardiovascular Magnetic Resonance

DOI: 10.1186/1532-429x-14-s1-o22