Evaluation of the rotator cuff and glenoid labrum using a 0.2‐Tesla extremity magnetic resonance (MR) system: MR results compared to surgical findings

Abstract

The purpose of this investigation was to evaluate the diagnostic capabilities of magnetic resonance imaging (MRI) performed using a dedicated-extremity MR system in detecting lesions of the rotator cuff and glenoid labrum. This retrospective study compared the MR results obtained in 47 patients that underwent MRI using a 0.2-Tesla extremity MR system (E-scan) to the surgical findings. MR images of the shoulder were obtained as follows: shoulder coil, T1-weighted, coronal-oblique and axial images; short Tau inversion recovery (STIR), coronal-oblique images; and T2-weighted, coronal-oblique, sagittal-oblique, and axial images. The MR examinations were interpreted by three highly experienced, musculoskeletal radiologists. Open surgical (N ‫؍‬ 26) or arthroscopic (N ‫؍‬ 21) procedures were performed within a mean time of 33 days after MRI. The surgical findings revealed rotator cuff tears in 28 patients and labral lesions in 9 patients. For the rotator cuff tears, the sensitivity, specificity, positive predictive value, and negative predictive value were 89%, 100%, 100%, and 90%, respectively. For the labral lesions, the sensitivity, specificity, positive predictive value, and negative predictive value were 89%, 95%, 80%, and 97%, respectively. The findings indicated that there was good agreement comparing the MR results obtained using the low-field extremity MR system to the surgical findings for determination of lesions of the rotator cuff and glenoid labrum. Notably, the statistical values determined for the use of this MR system were comparable to those reported in the peerreviewed literature for the use of whole-body, mid-and high-field-strength MR systems.

Assessment of the rotator cuff and glenoid labrum using an extremity MR system: MR results compared to surgical findings from a multi‐center study

“…Notably, findings from the present study are comparable to those reported for shoulder MR imaging performed using mid-and high-field-strength MR systems. Additionally, our results are similar to those reported by Shellock et al (3), that also utilized an extremity MR system (sensitivity, 89%; specificity, 100%) and, as such, extend the experience of the use of this scanner to a multi-center study. With regard to the false negative rotator cuff examinations, most of these occurred at one orthopedic MRI facility (Oklahoma City, OK) and, thus, may be related to the particular surgical technique, diagnostic criteria, or patient population associated with this site.…”

“…The radiologists were not provided instructions or guidance with regard to specific criteria to use in interpreting the MR images, nor were concessions made for the low-field-strength MR images. However, standard, previously described, well-accepted interpretation criteria were used (1)(2)(3)(4)(5)(12)(13)(14)19). A partial rotator cuff tear was designated as an incomplete tendon defect that was outlined by high signal intensity on MR images with T2-weighted contrast.…”

“…Accordingly, data for the MR findings were obtained directly from the original preoperative reports, while data for the surgical findings were obtained from the original operative reports. With regard to the rotator cuff, terms such as tendinosis, tendonopathy, fraying, fibrillation, and degeneration were categorized as no tear in this study (3).…”

“…MAGNETIC RESONANCE (MR) IMAGING is regarded as a useful and accurate technique for diagnosing shoulder disorders, including rotator cuff disease and lesions of the glenoid labrum (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). MR imaging of the shoulder has been predominantly performed by using wholebody MR systems operating at high-field-strengths (1.0 -1.5 Tesla) or, more recently, utilizing low-fieldstrength (0.2-0.35 Tesla) scanners (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16).…”

“…MR imaging of the shoulder has been predominantly performed by using wholebody MR systems operating at high-field-strengths (1.0 -1.5 Tesla) or, more recently, utilizing low-fieldstrength (0.2-0.35 Tesla) scanners (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). In 2001, Shellock et al (3) studied the diagnostic capabilities of an extremity MR system for identifying shoulder pathology.…”