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Updated: Aug 27, 2025
Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
Application of deep learning-based image reconstruction in MR imaging of the shoulder joint to improve image quality
Malwina Kaniewska1,2, Eva Deininger-Czermak3,4,5, Jonas M Getzmann3,4
1Institute of Diagnostic and Interventional Radiology, University Hospital Zurich (USZ), Raemistrasse 100, CH-8091, Zurich, Switzerland. malwina.kaniewska@usz.ch.
Objectives:
To compare the image quality and diagnostic performance of conventional motion-corrected periodically rotated overlapping parallel line with enhanced reconstruction (PROPELLER) MRI sequences with post-processed PROPELLER MRI sequences using deep learning-based (DL) reconstructions.
Methods:
In this prospective study of 30 patients, conventional (19 min 18 s) and accelerated MRI sequences (7 min 16 s) using the PROPELLER technique were acquired. Accelerated sequences were post-processed using DL. The image quality and diagnostic confidence were qualitatively assessed by 2 readers using a 5-point Likert scale. Analysis of the pathological findings of cartilage, rotator cuff tendons and muscles, glenoid labrum and subacromial bursa was performed. Inter-reader agreement was calculated using Cohen's kappa statistic. Quantitative evaluation of image quality was measured using the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).
Results:
Mean image quality and diagnostic confidence in evaluation of all shoulder structures were higher in DL sequences (p value = 0.01). Inter-reader agreement ranged between kappa values of 0.155 (assessment of the bursa) and 0.947 (assessment of the rotator cuff muscles). In 17 cases, thickening of the subacromial bursa of more than 2 mm was only visible in DL sequences. The pathologies of the other structures could be properly evaluated by conventional and DL sequences. Mean SNR (p value = 0.01) and CNR (p value = 0.02) were significantly higher for DL sequences.
Conclusions:
The accelerated PROPELLER sequences with DL post-processing showed superior image quality and higher diagnostic confidence compared to the conventional PROPELLER sequences. Subacromial bursa can be thoroughly assessed in DL sequences, while the other structures of the shoulder joint can be assessed in conventional and DL sequences with a good agreement between sequences.
Key Points:
• MRI of the shoulder requires long scan times and can be hampered by motion artifacts. • Deep learning-based convolutional neural networks are used to reduce image noise and scan time while maintaining optimal image quality. The radial k-space acquisition technique (PROPELLER) can reduce the scan time and has potential to reduce motion artifacts. • DL sequences show a higher diagnostic confidence than conventional sequences and therefore are preferred for assessment of the subacromial bursa, while conventional and DL sequences show comparable performance in the evaluation of the shoulder joint.
Insights
Deep learning (DL) reconstructions of accelerated PROPELLER MRI sequences significantly improve shoulder imaging quality and diagnostic confidence compared to conventional methods. DL sequences are particularly beneficial for assessing the subacromial bursa, offering superior visualization.
Area of Science:
- Radiology
- Medical Imaging
- Artificial Intelligence in Medicine
Background:
- Shoulder MRI scans often involve lengthy acquisition times and are susceptible to motion artifacts.
- Accelerated MRI techniques, such as PROPELLER, aim to reduce scan duration and motion-induced artifacts.
- Deep learning (DL) based reconstructions offer potential for noise reduction and image quality enhancement in MRI.
Purpose of the Study:
- To compare the diagnostic performance and image quality of conventional PROPELLER MRI sequences with DL-reconstructed PROPELLER sequences.
- To evaluate the effectiveness of DL in accelerating scan times while maintaining or improving image quality for shoulder MRI.
Main Methods:
- A prospective study involving 30 patients comparing conventional PROPELLER MRI (19 min 18 s) with accelerated DL-reconstructed PROPELLER MRI (7 min 16 s).
- Qualitative assessment of image quality and diagnostic confidence by two readers using a 5-point Likert scale.
- Quantitative analysis of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).
Main Results:
- DL-reconstructed sequences demonstrated significantly higher mean image quality and diagnostic confidence (p=0.01).
- Mean SNR (p=0.01) and CNR (p=0.02) were significantly improved with DL sequences.
- Subacromial bursa thickening (>2 mm) was detected exclusively in 17 cases using DL sequences, while other structures showed comparable evaluation between conventional and DL methods.
Conclusions:
- Accelerated PROPELLER MRI with DL post-processing yields superior image quality and diagnostic confidence over conventional PROPELLER MRI.
- DL sequences are preferred for detailed subacromial bursa assessment, while both conventional and DL sequences provide comparable evaluation for other shoulder joint structures.
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