7-T clinical MRI of the shoulder in patients with suspected lesions of the rotator cuff

Abstract

Background: To evaluate feasibility and diagnostic performance of clinical 7-T magnetic resonance imaging (MRI) of the shoulder.Methods: Eight patients with suspected lesions of the rotator cuff underwent 7-T MRI before arthroscopy. Image quality was scored for artifacts, B 1 + inhomogeneities, and assessability of anatomical structures. A structured radiological report was compared to arthroscopy. In four patients, a visual comparison with pre-existing 1.5-T examinations was performed. Results: Regarding image quality, the majority of the sequences reached values above the middle of each scoring scale. Fat-saturated proton density sequences showed least artifacts and best structure assessability. The most homogenous B 1 + field was reached with gradient-echo sequences. Arthroscopy did not confirm tendinopathy/ partial tear of supraspinatus in 5/8 patients, of subscapularis in 5/6, and of infraspinatus in one patient; only a partial lesion of the subscapularis tendon was missed. Pathologic findings of long bicipital tendon, acromioclavicular joint, glenohumeral cartilage, labrum, and subacromial subdeltoideal bursa were mainly confirmed; exceptions were one lesion of the long bicipital tendon, one subacromial bursitis, and one superior glenoid labrum anterior-to-posterior lesion, missed on 7-T MRI. Evaluating all structures together, sensitivity was 86%, and specificity 74%. A better contrast and higher image resolution was noted in comparison to previous 1.5-T examinations. Conclusions: 7-T MRI of the shoulder with diagnostic image quality is feasible. Overrating of tendon signal alterations was the main limitation. Although the diagnostic performance did not reach the current results of 3-T MRI, our study marks the way to implement clinical 7-T MRI of the shoulder.

Musculoskeletal MRI at 7 T: do we need more or is it more than enough?

“…Compared to 1.5-T MRI, higher contrast and spatial resolution obtained at 7 T led to a better image quality and morphological assessment of alterations of the articular structures, including cartilage. Nevertheless, the diagnostic performance of 7-T MRI did not result superior to the results of 3-T MRI reported in the literature [ 17 ].…”

“…Lazik-Palm et al [ 17 ] first demonstrated the feasibility of shoulder clinical protocol acquisition at 7 T with diagnostic image quality. Compared to 1.5-T MRI, higher contrast and spatial resolution obtained at 7 T led to a better image quality and morphological assessment of alterations of the articular structures, including cartilage.…”

“…A comparison between 7-T MRI and arthroscopy of the shoulder has been performed by Lazik-Palm et al [ 17 ], demonstrating the feasibility of clinical protocol acquisition at 7 T with diagnostic image quality in patients with suspected tendinopathy of the rotator cuff. Compared to the arthroscopic evaluation, 7-T MRI led to an overestimation of tendinopathy, especially regarding supraspinatus and subscapularis tendons.…”

“…This was explained by the authors, on the one hand, with the interpretation bias due to the magic angle effect, which creates artefactual hyperintensities in structures orientated at 55° to the main magnetic field, even if reduced compared to lower field strengths. On the other hand, the expected higher resolution of 7-T imaging and the patient selection criteria might have led to a misinterpretation of the signal alterations [ 17 ]. At the state of the art, the diagnostic accuracy of 3-T MRI still remains superior to 7-T MRI of the shoulder [ 17 ] and further studies are needed in order to include UHF-MRI of the shoulder in clinical practice.…”

“…On the other hand, the expected higher resolution of 7-T imaging and the patient selection criteria might have led to a misinterpretation of the signal alterations [ 17 ]. At the state of the art, the diagnostic accuracy of 3-T MRI still remains superior to 7-T MRI of the shoulder [ 17 ] and further studies are needed in order to include UHF-MRI of the shoulder in clinical practice.…”