How to Accelerate Cardiac MRI Examination: Cine-Sequences with Compressed Sensing (CS) Technology (Preliminary Results)

Introduction: Long examination times of functional cardiac magnetic resonance imaging (CMR) studies are burdensome especially for pediatric patients and adults in poor general condition. A new compressed sensing technology allows shortening of acquisition time by combination of k-space incoherent subsampling and iterative reconstruction algorithms.

Methods and Results: In five EMAH-patients with a mean age of 26.4 years (18–34 y, 2 males, 3 females) routinely performed cine sequences were compared with accelerated sequences by compressed sensing with regard to quantification results and image quality. All CMR studies were performed on a 3T-MRI scanner (MagnetomVIDA, Siemens Healthineers, Erlangen). Axial stacks with a slice thickness of 5–6 mm were acquired over the whole thorax. Image quality analysis was performed by two experienced readers in consensus (Likert scale, maximum 10points for best quality; criteria: endocardial borders, AV-valves, wall motion assessment, artifacts). Standard cine sequences consisted of TrueFISP or FLASH sequences. CS-trueFISP-sequence parameters were as follows: TR 40.48 ms, TE 1.61 ms, flip angle 55°, acquisition bandwidth 977 Hz/Px, segments 11, number of slices 30, field of view 280 × 236 mm², matrix 256 × 212, CS-factor 9.6—with small interindividual variations. Mean examination duration was approximately five times faster for the CS-sequences (2–3 min vs. 10–14 min). Acquired stroke volumes with regular cine sequences showed a mean deviation of -5.7% for the left ventricle (LV) respectively −0.4% for the right ventricle (RV) compared with the flow volume quantifications in the ascending aorta and pulmonary trunk (AV-valve regurgitation previously excluded). CS-cine sequences showed a mean deviation of −7% for the LV and −4.5% for the RV. Results for the ejection fraction (EF) were not significantly influenced by CS-acceleration (−2.7% LV-EF and 2.0% RV-EF). The regular sequences got a mean image quality score of 9.2 points versus 7.2 points for the CS-sequences.

Conclusion: Quantification results and image quality analysis suggest, that CS-accelerated cine sequences provide a time saving equivalent alternative to regular cine sequences without relevant loss in image quality.

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