Optimizing Liver Magnetic Resonance Imaging: Does Intuitive Protocol Management Software Save Time and Produce Better Scans than Manually Optimized Protocols?

Free-breathing accelerated whole-body MRI using an automated workflow: Comparison with conventional breath-hold sequences

Whole-body magnetic resonance imaging (MRI) has become increasingly popular in oncology. However, the long acquisition time might hamper its widespread application. We sought to assess and compare free-breathing sequences with conventional breath-hold examinations in whole-body MRI using an automated workflow process. This prospective study consisted of 20 volunteers and six patients with a variety of pathologies who had undergone whole-body 1.5-T MRI that included T1-weighted radial and Dixon volumetric interpolated breath-hold examination sequences. Free-breathing sequences were operated by using an automated user interface. Image quality, diagnostic confidence, and image noise were evaluated by two experienced radiologists. Additionally, signal-to-noise ratio was measured. Diagnostic performance for the overall detection of pathologies was assessed using the area under the receiver operating characteristics curve (AUC). Study participants were asked to rate their examination experiences in a satisfaction survey. MR free-breathing scans were rated as at least equivalent to conventional MR scans in more than 92% of cases, showing high overall diagnostic accuracy (95% [95% CI 92-100]) and performance (AUC 0.971, 95% CI 0.942-0.988; p < 0.0001) for the assessment of pathologies at simultaneously reduced examination times (25 ± 2 vs. 32 ± 3 min; p < 0.0001). Interrater agreement was excellent for both free-breathing (ϰ = 0.96 [95% CI 0.88-1.00]) and conventional scans (ϰ = 0.93 [95% CI 0.84-1.00]). Qualitative and quantitative assessment for image quality, image noise, and diagnostic confidence did not differ between the two types of MR image acquisition (all p > 0.05). Scores for patient satisfaction were significantly better for free-breathing compared with breath-hold examinations (p = 0.0145), including significant correlations for the grade of noise (r = 0.79, p < 0.0001), tightness (r = 0.71, p < 0.0001), and physical fatigue (r = 0.52, p = 0.0065). In summary, free-breathing whole-body MRI in tandem with an automated user interface yielded similar diagnostic performance at equivalent image quality and shorter acquisition times compared to conventional breath-hold sequences.

Utility of the luminance standard deviation to quantify magnetic resonance imaging motion artifact induced by tongue movement

Clear magnetic resonance imaging (MRI) is required to diagnose tongue cancer. However, the absence of occlusal support may cause tongue movements which are known to introduce artifacts on the MR image. This pilot study compared the manifest of artifacts from the tongue at rest and during motion using luminance standard deviation (LSD) to quantify the artifacts, in dentulous subjects. Participants were ten dentulous participants (5 males, 5 females; age 31.50 ± 8.38 years) with occlusal support. MRI was conducted with the tongue at rest and during lateral movement. The LSD was measured in the regions of interest (ROI) in the axial and sagittal planes. Tongue movement evoked unclear MR images, compared with the images taken at rest. Statistical analysis revealed that the LSD significantly differed between the tongue at rest and in motion in the axial (P = 0.004) and sagittal planes (ROI-A: P = 0.002, ROI-P: P = 0.006). These findings suggest that tongue movement introduces motion artifact and the LSD responds quantitatively to the magnitude of artifacts. Future studies will evaluate whether a prosthetic device used to provide occlusive support can decrease these artifacts when analyzed using LSD.