Magnetic resonance angiography with compressed sensing: An evaluation of moyamoya disease

Abstract

Compressed sensing (CS) reconstructions of under-sampled measurements generate missing data based on assumptions of image sparsity. Non-contrast time-of-flight MR angiography (TOF-MRA) is a good candidate for CS based acceleration, as MRA images feature bright trees of sparse vessels over a well-suppressed anatomical background signal. A short scan time derived from CS is beneficial for patients of moyamoya disease (MMD) because of the frequency of MR scans. The purpose of this study was to investigate the reliability of TOF-MRA with CS in the evaluation of MMD. Twenty-two patients were examined using TOF-MRA with CS (CS-TOF) and parallel imaging (PI-TOF). The acceleration factors were 3 (CS3) and 5 (CS5) for CS-TOF, and 3 (PI3) for PI-TOF. Two neuroradiologists evaluated the MMD grading according to stenosis/occlusion scores using the modified Houkin’s system, and the visibility of moyamoya vessels (MMVs) using a 3-point scale. Concordance was calculated with Cohen’s κ. The numbers of MMVs in the basal ganglia were compared using Bland-Altman analysis and Wilcoxon’s signed-rank tests. MRA scan times were 4:07, 3:53, and 2:42 for PI3, CS3, and CS5, respectively. CS-reconstruction completed within 10 minutes. MMD grading and MMV visibility scales showed excellent correlation (κ > .966). Although the number of MMVs was significantly higher in CS3 than in PI3 (p < .0001) and CS5 (p < .0001), Bland-Altman analysis showed a good agreement between PI3, CS3, and CS5. Compressed sensing can accelerate TOF-MRA with improved visualization of small collaterals in equivalent time (CS3) or equivalent results in a shorter scan time (CS5).

Clinical feasibility study of 3D intracranial magnetic resonance angiography using compressed sensing

“…From our results, CS techniques also can reduce the SENSE ghost artifacts, highlight the blood signal in the blood vessel, and suppress the background signal. Similar findings have been found in previous studies that the image quality of CS‐MRA is higher than MRA which only using a parallel imaging technique, with more than an acceleration factor of 3 . CS‐MRA scan was successfully performed in all enrolled patients without any technical problems in our study, which demonstrated its good feasibility and stability, consistent with a previous study …”

“…In addition, CS‐MRA could reduce the scanning time through reconstruction with sparse undersampling of k ‐space data by exploiting image redundancies. In our study, the mean acquisition time of CS‐MRA was 2 minutes and 54 seconds, whereas Con‐MRA took 5 minutes and 49 seconds, the same as a previous study where the scanning time of CS‐MRA was 2 minutes and 42 seconds with an acceleration factor of 5 . The scanning time of Con‐MRA (nearly 6 min) is slightly longer for patients throughout the MRA scan, especially for patients with severe brain disease.…”

“…In our study, the mean acquisition time of CS-MRA was 2 minutes and 54 seconds, whereas Con-MRA took 5 minutes and 49 seconds, the same as a previous study where the scanning time of CS-MRA was 2 minutes and 42 seconds with an acceleration factor of 5. 25 The scanning time of Con-MRA (nearly 6 min) is slightly longer for patients throughout the MRA scan, especially for patients with severe brain disease. The scanning time of CS-MRA (less than 3 min) would be much easier for patient cooperation to remain still through the entire scan to obtain good-quality images.…”

Hybrid of Compressed Sensing and Parallel Imaging Applied to Three-dimensional Isotropic T₂-weighted Turbo Spin-echo MR Imaging of the Lumbar Spine

“…Hybrid CS was effective in high-contrast areas, so it was applied to MRA, the cine-image sequences of cardiac MRI, and MRCP. 8,12,16 The contrast and SNR of CSF for hybrid-CS were significantly higher compared with those for SENSE. However, contrast and SNR of muscle and fat for hybrid-CS were significantly lower compared with those for SENSE.…”

“…Previous reports mainly evaluated the usefulness of CS technique for reducing the scan time preserving image quality in sparse data such as magnetic resonance choledochopancreatography (MRCP) and brain MR angiography. 11,12 However, most MR images are not sparse in generalmost of the pixels in an MR image are not black, but contain many levels of the grayscale. Therefore, CS is not widely used for routine examinations.…”