Premed Academy, Colby College, Waterville, ME A Comparison between MRI Findings and Post Operative Reports of Labral Tears in the Shoulder Breanna Davis ‘16, Dr. Chris Lutrzykowski MD, Dr. James Dunlap MD, Dr. Anthony Mancini MD Premed Academy, Colby College, Waterville, ME Abstract This experiment investigates the effectiveness of MR arthrography in 28 patients seen at Maine General Orthopedics over the last three years. All 28 patients had an arthroscopic surgery on the shoulder’s labrum by Dr. Anthony Mancini. I hypothesized the MR arthrography was accurate in diagnosing tears, but not accurate in describing the size and location of the tears. The results found portray the accuracy between MR arthrography findings and the post-operative reports. The study focuses not only on the ability of the MR arthrography to detect a labral tear, but also its effectiveness of finding the location (superior, posterior, inferior, or anterior) and size (Type I, II, III, IV). Using the details in reports, the MR arthrography’s ability to describe and diagnose labral tears was found to be exact only 54% of the time, which supported my hypothesis. Methods MR arthrography and operative reports of patients who had an arthroscopic surgery for labral lesions by Dr. Anthony Mancini at Maine General Orthopedics in the last 3 years were compared. Dr. Mancini completed a total of 35 surgeries since January 1, 2012, but only 28 patients had MR Arthrograms before the surgery and could be considered in the results. The patients ranged from 16 to 70 years old (mean, 37 years old). The summaries of findings from the two reports were recorded and the difference between the two was noted. Differences noted were in size, location, and misdiagnosis of the tear. Results 28 of the 35 patients that received arthroscopic surgeries by Dr. Mancini for labral tears had MR Arthrography done prior to the surgery. From the MRI with contrast, 27 patients of 28 (96%) were diagnosed with a labral tear. Comparing the post-operative reports to the MR Arthrography reports, 15 (54%) of 28 had the same diagnosis and 13 (46%) of 28 differed. The MRI with contrast reports differed completely in location of the tear (4 of 28, 14%), partially in locations (4 of 28, 14%), and tear size (3 of 28, 11%). One did not show any tear at all (1 of 28, 4%). Interesting findings that were not the focus of the study included that 4 (14%) of the 28 patients MR Arthrograms missed rotator cuff tears, 2 (100%) of 2 Type I SLAP, Superior Labrum Anterior to Posterior, tears were not found in MRI reports, and one patient with a MRI without contrast reported a rotator cuff tear, but the operative report found a Type II SLAP tear and no tear in the rotator cuff. Introduction A special type of MRI procedure, known as MR arthrography, is used to verify a labral lesion in both the shoulder and hip joints. MR Arthrography, also known as MRI with contrast, has been found to be the most effective way to diagnose a labral tear before surgery. MR arthrography, MR imaging, CT arthrography are all tools used in medicine to diagnose labral injuries without surgery. Of the three, MR arthrography has been found to be the best at detecting a labral tear (Figure 1) and to give the clearest image of the inferior part of the labrum (Glenoid Labral Tears: Prospective Evaluation with MR Imaging, MR arthrography, and CT Arthrography, Chandnani, et al.). MR arthrography has also been reported to enhance accuracy MRI report of both the glenoid labrum and the rotator cuff tendon (MR Arthrography of the Shoulder: Comparison with Conventional MR Imaging, Flannigan, et al.). I hypothesized that MR arthrography was often inaccurate in identifying exact location and size of tears. To test the hypothesis, this study compares the MRI with contrast reports to the operative findings of 28 patients with labral tears of the shoulder that were seen by Dr. Anthony Mancini since January 2012. The consistency between the findings will reveal the accuracy of the MRI procedure at Maine General Orthopedics over the last 3 years.  Discussion Although MR arthrography has proved to be the most effective way thus far to identify a labral tear without operation, clinicians at Maine General Orthopedics have found it to not give the most accurate results. Over the last 3 years at Maine General Orthopedics, Dr. Mancini has reported the exact same findings as the MR arthrogram in only 54% of his shoulder labrum procedures. MR arthrography did effectively (96%) detect a labral tear, however the entire location (14%), the size (11%), or some of the locations (14%) of the tear differed in 46% of the total patients. These results support my hypothesis and concludes there was a lack of accuracy in either the imaging of MR arthrography, or in the interpretation of the images.   This study did not focus on rotator cuff tears, however, 14% of the 28 patient had rotator cuff tears that were not reported in MRI findings and one patient was reported to have a rotator cuff tear on their MRI without contrast, but actually had a labral tear. MRIs, with and without contrast, appear to be ineffective at visually describing the difference between a tear in the rotator cuff and a tear in the labrum. Further studies comparing the MRI reports to the operative reports of labral and rotator cuff surgeries might portray even more information towards the lack of accuracy in finding the exact type of labral tear is present. Lastly, all of the Type I SLAP tears found in surgery were not on the MRI with contras reports. Therefore, MR arthrography failed to find Type I SLAP tears in this study. Figure 1: MR arthrogram of right shoulder. SLAP lesion is circled in the yellow circle.