Isotropic MR imaging of the shoulder with multiplanar reconstruction (MPR) is a useful method in diagnosing labrum and rotator cuff tears, especially for anterior labral tears related to anterior instability, according to a study by Korean researchers.
The imaging modality and technique also are beneficial in diagnosing supraspinatus and infraspinatus complex tears with an accuracy rate of greater than 90%.
The study comes from the radiology department at Samsung Medical Center at Sungkyunkwan University School of Medicine in Seoul. Lead author Dr. Young Cheol Yoon presented the results at the recent RSNA meeting in Chicago.
Yoon cited previous research, which concluded that shoulder imaging with conventional 3-tesla MRI "produces high accuracy in the diagnosis of labrum tears and abnormalities of the supraspinatus tendons."
"On the other hand, isotropic [3T] imaging can allow us to save scan time by using single data acquisition and by obtaining diverse images," he noted.
3-tesla MRI advances
In addition, 3-tesla MRI has improved signal-to-noise ratio for use when speed is needed for faster and higher-resolution images. "The faster imaging can lead to decreased motion artifacts and increase the convenience of the patient," Yoon added.
Isotropic imaging using MPR with a 3-tesla MRI system shows the labrum and rotator cuff region as well as conventional imaging in a short time. However, there are no prospective studies concerning the usefulness of short imaging using isotropic imaging, Yoon noted.
Thus, the purpose of the study was to prospectively compare the diagnostic accuracy of isotropic 3-tesla MR imaging using the MPR technique with conventional MR arthrography for diagnosing labrum and rotator cuff lesions.
Patient protocol
Over a period of four months, 36 patients (16 men and 20 women, with an average age of 53 years) were enrolled in the study.
All patients were scheduled for shoulder arthroscopic surgery and underwent preoperative indirect MR arthrography one day before their respective operations. After an intravenous injection of gadolinium, adequate exercise of affected shoulder was encouraged. Isotropic MR images were obtained in a 180-mm field-of-view with a slice thickness of 0.7 mm, using a 3-tesla MRI system from Philips Healthcare of Andover, MA.
Two musculoskeletal radiologists evaluated the isotropic MR images with MPR using 3D software. The pair recorded the presence or absence of superior labrum from anterior to posterior (SLAP) lesions, anterior labral tears related to anterior instability, subscapularis tears, supraspinatus and infraspinatus (SSP-ISP) complex tears, and long head of the biceps tendon (LBT) tears.
An orthopedic surgeon performed shoulder arthroscopic surgery, using that procedure as the gold standard for comparison and diagnosis, and noted the same conditions of each patient.
Lesion discoveries
The surgeon discovered and confirmed 11 SLAP lesions, 10 anterior labral tears related to anterior instability, 21 subscapularis tears, 24 SSP-ISP complex tears, and 18 LBT tears.
In their analysis, the researchers found that isotropic 3-tesla MRI had 100% specificity and positive predictive value (PPV) for anterior labral tears related to anterior instability. The modality also had 100% sensitivity and negative predictive value (NPV) for supraspinatus and infraspinatus complex tears. Isotropic 3-tesla MRI also was perfect in specificity and PPV for LBT tears.
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One limitation noted by Yoon was that "all the patients in the study were scheduled for arthroscopic surgeries, so the diagnostic areas could have been overestimated."
Still, with those results, the researchers concluded that isotropic MR imaging of the shoulder with the MPR technique is beneficial in diagnosing labrum and rotator cuff tears, especially for anterior labral tears related to anterior instability.
And, with the compatible results between 3-tesla isotropic MRI with MPR and conventional MRI, the shorter scan time of isotropic 3-tesla MRI will be more convenient for patients.
By Wayne Forrest
AuntMinnie.com staff writer
December 29, 2008
Related Reading
MR arthrography outdoes 3-tesla MR on tendon tears, December 12, 2008
MR arthrography study finds 'optimal injection site,' October 24, 2008
Making the most of MRI to assess the rotator cuff pre- and postinjury, November 9, 2007
MRI keeps pace with rapidly evolving musculoskeletal systems of young athletes, May 20, 2007
MR arthrography depicts tears, instability in triangular fibrocartilage complex, January 19, 2007
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