Anterior Labral Tear: Diagnostic Value of MR Arthrography of the Shoulder

PURPOSE: To assess the accuracy of magnetic resonance(MR) arthrography in the diagnosis of anterior labral tear of the shoulder. MATERIALS AND METHODS: Between Semptember 1996 and February 2000, MR arthrography of the shoulder was performed in 281 patients with a history of shoulder pain or instability. Among this total, only 157 shoulders in 154 patients who underwent arthroscopy or open surgery 0 to 230 (average, 20.9) days after MR arthrography were included in this study; the subjects comprised of 150 males and 4 females with an average age of 23.3 years. MR arthrographs of these 154 patients were analyzed for the presence of anterior labral tears, and the findings were correlated with the arthroscopic and surgical findings. Anterior labral tear was classified as A to D according to its location, as determined by arthroscopy and surgery. (A=4 to 6 o 'clock direction, anteroinferior; B=2 to 4 o 'clock direction, central; C=12 to 2 o 'clock direction, anterosuperior; D= SLAP lesions). The retrospective analysis of MR arthrographs showing false-positive and negative findings was also undertaken. RESULTS: In the diagnosis of anterior labral tear, MR arthrography showed a sensitivity of 94%, a specificity of 90% and an accuracy of 91%. Anterior labral tears were confirmed by arthroscopy or surgery in 62 of the 157 shoulders (39%). Among 62 lesions, two (3%) were observed in area A, 32(52%) in area A+B, nine (15%) in area A+B+C, one(2%) in area A+B+D, 13(21%) in area A+B+C+D, two (3%) in area B+C, one(2%) in area B+D, and two(3%) in area C. Among ten false-positive cases, seven were focal lesions (two, three and two lesions in area A, B and C, respectively), and in the remaining three cases, located in area A+B, MR arthrography revealed thickening and deformation. All four false negatives were focal lesions (two in area A and two in area C). CONCLUSION: Other than in focal lesions, in which accuracy was relatively low, MR arthrography showed high sensitivity, specificity and accuracy in the diagnosis of anterior labral tear of the shoulder.

Subchondral Cysts of the Humeral Head: MR Imaging Findings

PURPOSE: To evaluate the findings of subchondral cyst of the humeral head, as seen on shoulder MRarthrography MATERIALS AND METHODS: Sixty-three patients( M:F=62:1 ; mean age 23 years) who underwent shoulder MRarthrography between September 1996 and May 1998 were retrospectively reviewed. No patient had a history of eithershoulder dislocation or certain diseases known to be commonl accompanied by subchondral cysts. All MR images wereobtained using a 1.5 Tesla unit after intraarticular injection of 20ml of diluted contrast material. T1 andT2-weighted axial, oblique coronal, and oblique sagittal images were analysed for the presence, location, number,shape, size, and connection to the joint cavity of subchondral cysts. RESULTS: We identified 58 subchondral cystsin 43(71.7%) of 63 cases. All were located in the posterolateral portion of the humeral head, and on the physealline. Twenty-eight patients(65.1%) had one cyst, and 15(34.9%) had two. Thirty-four cysts(58.6%) were round orovoid in shape and, 2-8mm in diameter(average, 3.9mm) ; 24(41.4%) were lobulated and 3-10mm in diameter(average5.3mm). Fifty-three cysts(91.4%) were connected to the joint cavity. CONCLUSIONS: In symptomatic patients, the incidence of subchondral cyst of the humeral head was 71.7%. All were located in the posterolateral portion, andon the physeal line. Most subchondral cysts were connected with the joint cavity.

A Study to Assess by Means of MR Arthrography the Causal Relationship between Anterior Capsular Attachment Typeand Anterior Instability of the Glenohumeral Joint

PURPOSE: To evaluate by means of MR arthrography the causal relationship between anterior capsularattach-ment type and anterior instability of the glenohumeral joint. MATERIALS AND METHODS: Sixty-five patients (M:F=64:1; mean age, 23 years), who had undergone shoulder MR arthrography were retrospectively reviewed. There wasno history of traumatic dislocation, and medical records relating to anterior instability were available. Physicalexamination revealed anterior instability in 25 patients(Group A), while in 40 (Group B), this was eithersuspicious or absent. With the aid of general anesthe-sia, 32 patients who had undergone surgery were physicallyexamined. Anterior instability was evident in 16 patients(Group C), and suspicious or absent in the remaining 16(Group D). All images were obtained after in-traarticular injection of Gd-DTPA. Fat-suppressed T1 axial imagingwas used to evaluate anterior capsular at-tachment type at mid and distal three-fourths levels of the glenoidfossa. The causal relationship between ante-rior capsular attachment types and anterior instability was analyzedusing the x2 test RESULTS: In group A, type I was most common at distal three-fourths level, and types I and IIwere equal and more common than type III at mid level. In group B, type I anterior capsular attachment type wasmost com-mon at both mid and distal three-fourths level. In these groups, no statistical significance was notedbetween anterior capsular attachment type and anterior instability (p value 0.611: 0.567). In group C, types I andII were equal and more common than type III at both mid and distal three-fourths level, while in group D, type IIwas most common at mid level, and type I was most common at distal three-fourths level. In these groups, nostatistical significance was noted between anterior capsular attachment type and anterior instability (p val-ue,0.772). CONCLUSION: There was no statistically significant difference between anterior capsular attachment typeand anterior instability of the shoulder joint.