Accelerated MRI of the Lumbar Spine Using Compressed Sensing: Quality and Efficiency

Abstract

Background Decreasing MRI scan time is a key factor to increase patient comfort and compliance as well as the productivity of MRI scanners. Purpose/Hypothesis Compressed sensing (CS) should significantly accelerate 3D scans. This study evaluated the clinical application and cost effectiveness of accelerated 3D T2 sequences of the lumbar spine. Study Type Prospective, cross‐sectional, observational. Population Twenty healthy volunteers and 10 patients. Field Strength/Sequence A 3D T2 TSE sequence, identical 3D sequences with three different parallel imaging and CS accelerating factors, and 2D TSE sequences as a clinical reference were obtained on a 3T scanner. Assessment Three readers evaluated the sequences for delineation of anatomical structures and image quality. A quantitative analysis consisting of root mean square error, structural similarity index, signal‐to‐noise ratio, and contrast‐to‐noise ratio were performed. The scan times were used to calculate cost differences for each sequence. Statistical Tests An analysis of variance with repeated measurements and the Friedman test were used to test for potential differences between the sequences. Post‐hoc analysis was made with the chi‐squared and Tukey–Kramer test. Results CS with factor 4.5 results in unchanged image quality compared to the T2 TSE for volunteers and patients (overall image impression: 4.75 vs. 4.20 [P = 0.73] and 4.90 vs. 4.47 [P = 0.44]). The CS 4.5 scan is 167 seconds (–39%) faster than the 3D and 216.5 seconds (–45%) faster than the 2D sequences. No significant differences was found for the diagnostic certainty in the volunteers and patients between 2D TSE and 3D CS 4.5 (P = 0.89 and P = 0.43). A reduction of scan time to 148 seconds (CS 8) was still rated acceptable for most diagnosis. Data Conclusion CS accelerates the 3D T2 without compromising image quality. The 3D sequences offer comparable diagnostic quality to the clinical 2D standard with less scan time (–45%), potentially increasing the productivity of MRI scanners. Level of Evidence: 1 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2019;49:e164–e175.

Reduction of procedure times in routine clinical practice with Compressed SENSE magnetic resonance imaging technique

“…We did observe differences with the exemplary acceleration factors published by the vendor, in some anatomies we did not achieve the same numbers, such as in brain imaging, where we achieved 25% acceleration compared to 45% predicted. In other anatomies we observed much higher acceleration factors, for example in lumbar spine where 25% was predicted, but in our case 41% acceleration was realized supporting previously published data of a scan time reduction of 45% for a 3D T2 TSE sequence of the lumbar spine [10]. These differences can be explained by the fact that the total acceleration factor is highly dependent on the protocols in the a priori situation, and therefore it is difficult to predict total acceleration factors of exam protocols without knowledge of the local situation and starting protocols.…”

Clinical application of free-breathing 3D whole heart late gadolinium enhancement cardiovascular magnetic resonance with high isotropic spatial resolution using Compressed SENSE

“…Recently, Compressed SENSE was introduced, which combines compressed sensing and parallel imaging using SENSitivity Encoding (SENSE) [29][30][31]. Compressed SENSE enables image-acquisition acceleration currently not achievable by compressed sensing or parallel imaging alone and has shown promising results in musculoskeletal and cardiovascular imaging [29][30][31][32][33][34][35][36].…”

Acceleration of Brain TOF-MRA with Compressed Sensitivity Encoding: A Multicenter Clinical Study

“…Each participant was scanned head-first in the supine position at 3T (Ingenia CX; Philips Healthcare) at 1 of the 5 centers where the MR imaging systems were located, with a 32-channel head coil using compressed SENSE as the acceleration technique 19,20 (a combination of CS and SENSE, hereafter referred to as CS-SENSE) with the reconstruction algorithm shown in Equation 1, which essentially followed the technique described by Lustig and Pauley: 21…”

“…In addition, the structural similarity index (SSIM) 24 was calculated to measure the image similarity between each of the 7 accelerated scans and the RS scan. 20 The whole MIP radial axis in the foot-head direction (radial angle ¼ 12°, fifteen projections in total, no preprocessing) was used for visual depiction of the cerebral arteries. Qualitative image evaluation was performed independently by 2 neuroradiologists (J.Y.…”