Optimizing scan times in clinical neuroimaging: the potential of synthetic MRI

Synthetic Magnetic Resonance Imaging (SI) generates images from parametric maps of tissue properties and derives contrast weightings from the same acquisition. We aimed to evaluate the potential for scan time reduction using SI in patients with neurological indications in a tertiary care cantonal hospital.

We searched our hospital database for head imaging performed between March 2020 and August 2022. Sequences were categorized as either fully replaceable (Scenario A) or potentially replaceable (Scenario B) if replacement would lead to limitations, such as resolution or contrast. We calculated the time used and potentially saved if all replaceable sequences and their respective planning were replaced by a 3-dimensional (3D) SI sequence lasting 3 or 5 min.

We identified 4,320 head examinations. Total examination time for replaceable sequence imaging in Scenario A was 656 h 54 min (minimum: 506 h 26 min; maximum: 982 h 53 min) and 778 h 38 min (minimum: 602 h 34 min; maximum: 1,223 h 34 min) for Scenario A & B. If 3D SI had been used, the estimated time required would have been 216 h for a 3-minute 3D SI and 360 h for a 5-minute 3D SI. The application of SI would have yielded an estimated reduction of 440 h 54 min (minimum: 290 h 26 min; maximum: 766 h 53 min) for Scenario A, and 562 h 38 min (minimum: 386 h 34 min; maximum: 907 h 34 min) for Scenario A & B.

Reducing scan time with 3D SI is feasible and depends on the scan time of 3D SI, the type and frequency of performed protocols, and its ability to meet high-quality requirements. The effectiveness is most pronounced when 3D SI can replace traditional weighted images while maintaining diagnostic standards.