Accelerated whole brain intracranial vessel wall imaging using black blood fast spin echo with compressed sensing (CS-SPACE)

Abstract

Objective Develop and optimize an accelerated, high-resolution (0.5 mm isotropic) 3D black blood MRI technique to reduce scan time for whole-brain intracranial vessel wall imaging. Materials and methods A 3D accelerated T1-weighted fast-spin-echo prototype sequence using compressed sensing (CS-SPACE) was developed at 3T. Both the acquisition [echo train length (ETL), under-sampling factor] and reconstruction parameters (regularization parameter, number of iterations) were first optimized in 5 healthy volunteers. Ten patients with a variety of intracranial vascular disease presentations (aneurysm, atherosclerosis, dissection, vasculitis) were imaged with SPACE and optimized CS-SPACE, pre and post Gd contrast. Lumen/wall area, wall-to-lumen contrast ratio (CR), enhancement ratio (ER), sharpness, and qualitative scores (1–4) by two radiologists were recorded. Results The optimized CS-SPACE protocol has ETL 60, 20% k-space under-sampling, 0.002 regularization factor with 20 iterations. In patient studies, CS-SPACE and conventional SPACE had comparable image scores both pre- (3.35 ± 0.85 vs. 3.54 ± 0.65, p = 0.13) and post-contrast (3.72 ± 0.58 vs. 3.53 ± 0.57, p = 0.15), but the CS-SPACE acquisition was 37% faster (6:48 vs. 10:50). CS-SPACE agreed with SPACE for lumen/wall area, ER measurements and sharpness, but marginally reduced the CR. Conclusion In the evaluation of intracranial vascular disease, CS-SPACE provides a substantial reduction in scan time compared to conventional T1-weighted SPACE while maintaining good image quality.

Visualizing wall enhancement over time in unruptured intracranial aneurysms using 3D vessel wall imaging

“…This is generally unacceptably long for routine clinical use. We and others are conducting studies using accelerated undersampling techniques that provide substantial reductions in acquisition times, and it appears that it is likely that these methods will provide reductions of acquisition time . Similarly, acquisitions at higher field strength provide opportunities for exploring signal‐to‐noise ratio (SNR) improvements that can be used to either provide increased resolution or reduced acquisition times .…”

“…We and others are conducting studies using accelerated undersampling techniques that provide substantial reductions in acquisition times, and it appears that it is likely that these methods will provide reductions of acquisition time. 23 Similarly, acquisitions at higher field strength provide opportunities for exploring signal-to-noise ratio (SNR) improvements that can be used to either provide increased resolution or reduced acquisition times. 8 Although the study results were encouraging in that only one acquisition failed to detect the aneurysm wall and artifact manifestation was low, reduced acquisition times would further limit any effects such as patient motion and could help improve all evaluation scores, providing a more complete assessment of the full surface area of each aneurysm.…”

SCMR Position Paper (2020) on clinical indications for cardiovascular magnetic resonance

“…This does not only concern imaging of atherosclerotic plaque, but also inflammatory changes associated with vasculitis and rheumatological diseases. CMR vessel wall imaging has been shown to be capable of detecting, characterizing and quantifying atherosclerotic plaque in the aorta [ 143 , 144 ], carotid arteries [ 145 , 146 ], lower extremity arteries [ 147 , 148 ] and even the coronary [ 149 , 150 ] and intracranial arteries [ 151 , 152 ]. The large FOV allows depiction of arterial wall changes over large anatomical trajectories.…”

Contrast-Enhanced High-Resolution Intracranial Vessel Wall MRI with Compressed Sensing: Comparison with Conventional T1 Volumetric Isotropic Turbo Spin Echo Acquisition Sequence

“…Several prior studies reported that CS achieved substantial scan time reduction while providing similar or superior SNR, CNR, VW delineation, and image quality in intracranial VW-MRIs (13,14). Those studies enrolled mostly healthy volunteers; therefore, validation in large patient cohorts was necessary to use CS in clinical practice.…”