Optimization of shoulder synthetic MRI through post-processing and comparison with conventional MRI

To evaluate the utility of synthetic MRI of the shoulder compared with conventional MRI and to optimize the parameters of morphological images through post-processing. Additionally, we aimed to assess the agreement of T2 values between multi-echo spin-echo (MESE) and multi-dynamic multi-echo (MDME) sequences.

Twenty healthy volunteers underwent shoulder MRI. The optimal post-processing parameters for the tendon-muscle contrast were examined using synthetic MRI, and two radiologists analyzed three image sets: conventional images, synthetic images using preset parameters, and optimized images. Qualitative analysis included assessment of the visibility of anatomical structures, overall image quality, and magic angle effect, whereas the quantitative analysis included measurement of the relative signal intensity and relative contrast. The T2 values of the articular cartilage and supraspinatus muscle were measured for each sequence.

Images synthesized with short echo times and long repetition times showed high tendon-muscle contrast. For fat-suppressed T2-weighted images, conventional images showed the highest image quality (p < 0.001), whereas the optimized images achieved comparable visibility of the rotator cuff (p = 0.031-1.0). No significant differences were observed among image sets in proton density-weighted images and T1-weighted images (p > 0.05). The T2 values of the MDME sequence were consistent with those of the MESE sequence at the muscle (p = 0.81), but were approximately 8.3 ms longer at the cartilage (p < 0.001).

Synthetic MRI provided acceptable image quality using appropriate post-processing parameters. The simultaneous acquisition of multiple morphological images and quantitative maps within five minutes holds promise for shoulder examination.