Reduction in Acquisition Time and Improvement in Image Quality in T2-Weighted MR Imaging of Musculoskeletal Tumors of the Extremities Using a Novel Deep Learning-Based Reconstruction Technique in a Turbo Spin Echo (TSE) Sequence

Abstract

Background: The aim of this study was to assess the technical feasibility and the impact on image quality and acquisition time of a deep learning-accelerated fat-saturated T2-weighted turbo spin echo sequence in musculoskeletal imaging of the extremities. Methods: Twenty-three patients who underwent MRI of the extremities were prospectively included. Standard T2w turbo inversion recovery magnitude (TIRMStd) imaging was compared to a deep learning-accelerated T2w TSE (TSEDL) sequence. Image analysis of 23 patients with a mean age of 60 years (range 30−86) was performed regarding image quality, noise, sharpness, contrast, artifacts, lesion detectability and diagnostic confidence. Pathological findings were documented measuring the maximum diameter. Results: The analysis showed a significant improvement for the T2 TSEDL with regard to image quality, noise, contrast, sharpness, lesion detectability, and diagnostic confidence, as compared to T2 TIRMStd (each p < 0.001). There were no differences in the number of detected lesions. The time of acquisition (TA) could be reduced by 52−59%. Interrater agreement was almost perfect (κ = 0.886). Conclusion: Accelerated T2 TSEDL was technically feasible and superior to conventionally applied T2 TIRMStd. Concurrently, TA could be reduced by 52−59%. Therefore, deep learning-accelerated MR imaging is a promising and applicable method in musculoskeletal imaging.

Keywords: accelerated turbo spin echo MRI; artificial intelligence; deep learning; musculoskeletal imaging; musculoskeletal tumors.

Figure 1

Bland-Altman plot to display the differences in the measurements of the lesion diameter between the T2-weighted TIRM_Std and the TSE_DL in reader 1 (left) and reader 2 (right).

Figure 2

Comparison of T2-weighted TSE_DL and T2 TIRM_Std. The T2 TIRM_Std shows a better image quality, contrast, and sharpness.

Figure 3

Follow up MRI examination of a 49-year-old with a T2w hyperintense lesion (arrows) of the right proximal femur, the finding would be compatible with enchondroma. The TSE_DL shows a better image quality, contrast, sharpness, and noise and thus, allows a better diagnostic confidence.

Figure 4

Follow-up MRI examination of an 81-year-old patient with Merkel cell carcinoma. As an incidental finding, the coronal TIRM_Std sequence shows a lipoma of the medial vastus muscle. The T2w TSE_DL shows a better image quality, noise, and sharpness than the TIRM_Std.

Figure 5

Follow-up MR examination of a 56-year-old male patient with histopathologically proven myxofibrosarcoma. T2w TSE_DL allows a better delineation of the conglomerate tumor of the left thigh due to better image quality, noise, sharpness, and contrast.