Faculty Bibliography

Purpose: Study the diagnostic accuracy of the 'smoke sign' on routine shoulder MR examinations for detection of pectoralis tendon humeral insertional injury.
Material(s) and Method(s): IRB approved, HIPAA compliant study. Radiology database queried for MR with reports containing 'pectoralis' and 'shoulder' from 9/2012 to 7/2018. Patients without prior pectoralis surgery with shoulder and pectoralis MR within 4 months, and shoulder MRpositive for pectoralis injury based on report and imaging review that clearly depicted pectoralis injury were included. Anonymized, randomized shoulder MR reviewed independently by two musculoskeletal fellowship-trained radiologists for 'smoke sign' on coronal- and sagittal-oblique sequences. Teaching session provided guidelines for smoke sign (ill-defined edema lateral or anterior to short head biceps/ coracobrachialis on coronal- and sagittal-oblique fluid-sensitive images, respectively) before reader review. AllMR reviewed by senior author for presence and location of pectoralis injury.
Result(s): 52 shoulder MR exams total: 33 patients with shoulder and pectoralis MR, 4 patients with shoulder MR and pectoralis imaging on same exam, 15 patients with shoulder MR only.14/52 exams didn't have pectoralis injury on shoulder or pectoralis MR; 'smoke sign' was present in none of these cases. Remaining 38 patients had pectoralis injuries; 24/38 (humeral avulsion), 4/38 (tendon tear) 8/38 (myotendinous junction), 2/38 (intramuscular injury). Pooled sensitivity, specificity, negative and positive predictive value for 'smoke sign' was 86%, 100%, 76% and 100%. When only tendon tears and avulsions were assessed, this rose to 100%, 100%, 100% and 100%. Kappa coefficient was 0.922 for the presence of the sign on coronal oblique 0.876 on sagittal oblique images. Smoke sign was present in all 8 surgically proven pectoralis injuries.
Conclusion(s): 'Smoke sign' is sensitive and specific for pectoralis humeral insertional injury, especially tendon tears and avulsions. Detection of this sign on routine shoulder MR should prompt careful evaluation of the distal pectoralis tendon and recommendation for dedicated pectoralis imaging

Purpose: To explore variation in downstream costs associated with cartilage lesions incidentally detected on radiographs. Materials andMethods: The cohort was composed of 120 patients with incidental, not previously diagnosed, cartilage lesions seen on appendicular plain radiographs. The population was divided into three subgroups based on the interpreting radiologist's description: enchondroma, lowgrade cartilage lesion, and chondrosarcoma. Downstream events (follow-up imaging, office visits, biopsy, tumor resection) associated with the lesions were identified from the electronic medical record. American College of Radiology (ACR) Appropriateness Criteria were used to classify radiologists' recommendations. NationalMedicare rates were used to estimate costs of downstream events. Average cost per lesion was stratified, and cost ratios were computed among subgroups.
Result(s): Average downstream cost per lesion was $75.56. Costs were 4.6 times greater in patients under the age of 65 than over. Costs were 13.2 and 13.7 times higher when radiologists characterized lesions as chondrosarcoma versus low-grade cartilage lesion and enchondroma, respectively. There was no statistically significant difference in costs between the subgroups when accounting for size and location of lesions. Compared to when follow-up imaging was neither recommended nor obtained, costs rose from $0 to $26.03 per patient when follow-up imaging was recommended and obtained, and $62.21 per patient when followup imaging was obtained despite not being recommended. Costs rose from $0 to $14.83 per patient when radiologists' recommendations for follow-up were adherent to the ACR guidelines for management of incidental bone lesions. Costs were 2.3 times greater when ordering physicians overmanaged compared with radiologists' recommendations. No malignancy was pathologically proven in the cohort.
Conclusion(s): Costs for incidental cartilage lesions vary. Size and location of lesions do not have a significant effect on downstream costs; however, radiologists' characterization and recommendation have an impact. Therefore, it is imperative that radiologists accurately characterize such lesions and recommendations reflect the best value for patient care

OBJECTIVE:To determine if hip 3D-MR imaging can be used to accurately demonstrate femoral and acetabular morphology in the evaluation of patients with femoroacetabular impingement. MATERIALS AND METHODS/METHODS:We performed a retrospective review at our institution of 17 consecutive patients (19 hips) with suspected femoroacetabular impingement who had both 3D-CT and 3D-MRI performed of the same hip. Two fellowship-trained musculoskeletal radiologists reviewed the imaging for the presence and location of cam deformity, anterior-inferior iliac spine variant, lateral center-edge angle, and neck-shaft angle. Findings on 3D-CT were considered the reference standard. The amount of radiation that was spared following introduction of 3D-MRI was also assessed. RESULTS:All 17 patients suspected of FAI had evidence for cam deformity on 3D-CT. There was 100% agreement for diagnosis (19 out of 19) and location (19 out of 19) of cam deformity when comparing 3D-MRI with 3D-CT. There were 3 type I and 16 type II anterior-inferior iliac spine variants on 3D-CT imaging with 89.5% (17 out of 19) agreement for the anterior-inferior iliac spine characterization between 3D-MRI and 3D-CT. There was 64.7% agreement when comparing the neck-shaft angle (11 out of 17) and LCEA (11 out of 17) measurements. The use of 3D-MRI spared each patient an average radiation effective dose of 3.09 mSV for a total reduction of 479 mSV over a 4-year period. CONCLUSION/CONCLUSIONS:3D-MR imaging can be used to accurately diagnose and quantify the typical osseous pathological condition in femoroacetabular impingement and has the potential to eliminate the need for 3D-CT imaging and its associated radiation exposure, and the cost for this predominantly young group of patients.

Hip MRI and arthroscopy have important roles for the evaluation of the patient with hip pain. An understanding of what orthopedic surgeons want to know before and after hip arthroscopy as well as the limitations of arthroscopy would enable radiologists to improve their imaging interpretations and produce more clinically relevant, management guiding reports. The goal of this article is to review the basic principles of hip arthroscopy and MRI and compare their strengths and weaknesses. Normal clinically relevant hip anatomy, important pathologic conditions such as labral tears and cartilage injuries, femoroacetabular impingement specific findings like cam and pincer morphology, extra-articular conditions such as abductor and iliopsoas tendons pathology and common post-operative appearances are reviewed on MRI and arthroscopy.

BACKGROUND:The goal of the Latarjet procedure is restoration of shoulder stability enabled by accurate graft positioning and union. This study aimed to establish a reproducible method of quantitatively assessing coracoid graft osseous union percentage (OUP) using computed tomography (CT) scans and to determine the effect of other factors on the OUP. MATERIALS AND METHODS/METHODS:Postoperative CT scans of 41 consecutive patients treated with the open Latarjet procedure (37% primary, 63% revision) for anterior glenohumeral instability were analyzed for the OUP, position of the graft, and screw type and angle. Two musculoskeletal radiologists independently examined the images 2 times, and intraobserver and interobserver reliability was calculated using intraclass correlation coefficient (ICC). RESULTS:Mean OUP was 66% (range, 0%-94%) using quantitate methods, with good intraobserver reliability (ICC = 0.795) and interobserver reliability (ICC = 0.797). Nonunion and significant graft resorption was found in 2 patients. No significant difference was found in the mean OUP in the primary (63%) vs. revision Latarjet procedure (67%). Grafts were flush in 39%, medial in 36%, and lateral in 8%. The medial and neutral graft position was associated with slightly higher OUP (72% and 69%) compared with lateral (65%). OUP was higher when the superior screw angle was less than 17° and the inferior screw angle was less than 24°. This difference did not reach statistical significance. Screw type was not associated with significant difference in OUP. CONCLUSION/CONCLUSIONS:Quantitative assessment of osseous union of the graft using a reproducible method that we introduced showed similar OUP in the primary and revision Latarjet procedure.

OBJECTIVE:The aim of this article is to review the postoperative MRI appearances of irreparable massive rotator cuff tears (RCTs) after surgery was performed using newer techniques, including patch repair, muscle tendon transfer, superior capsular reconstruction, and subacromial balloon implantation. CONCLUSION/CONCLUSIONS:Newer surgical techniques are emerging for the management of massive RCTs. As radiologists become increasingly likely to encounter postoperative imaging studies of RCTs repaired using these techniques, familiarity with the normal postoperative appearances and complications associated with these techniques becomes important.

OBJECTIVE:The purpose of this study was to determine whether adding DWI to conventional MRI of the sacroiliac joints improves the diagnostic performance of MRI readers in the detection of sacroiliitis. MATERIALS AND METHODS/METHODS:values of patients with and those without sacroiliitis were compared. RESULTS:AUC was 0.758 (95% CI, 0.67-0.83). CONCLUSION/CONCLUSIONS:The addition of DWI to conventional MRI does not significantly improve overall diagnostic performance in terms of accuracy, sensitivity, or confidence in the detection of inflammatory sacroiliitis, but it does have increased specificity and interobserver agreement. ADC threshold values can be used as predictors of sacroiliitis but give no added advantage over MRI with DWI.

Purpose: As glenohumeral osteoarthritis progresses, there is increased risk for posterior glenoid bone loss which impacts an increasingly common treatment for these patients, total shoulder arthroplasty. Defining the level of maximum posterior bone loss and accurate assessment of its severity, using glenoid version measurements, are crucial to correctly align the glenoid prosthesis with glenoid to prevent prosthetic failure. While the importance of this information is clear, how these measurements should be performed remains in question with several techniques described in the literature. The purpose of this study was to define the most accurate level to measure glenoid version on CT for the most clinically relevant variants of posterior glenoid bone loss, Walch B2 and B3 types. Materials and Methods: 386 consecutive CT shoulder studies performed for shoulder arthroplasty preoperative planning between 2013- 2016 were retrospectively reviewed. Patients with B2 and B3 glenoid types were included. Two radiologists measured glenoid retroversion independently according to Friedman method on true axial CT images using the "intermediate glenoid line", at three glenoid heights: 25% (upper) 50% (equator) and 75% (lower). Results: 29 B2 and 8 B3 glenoid types were included. There was no statistically significant difference found in the retroversion measurements performed by each reader at the three glenoid levels on the B2 or B3 glenoid types (Mean angles (%) in upper, equator and lower in B2: 16.5, 17,0 and 17.5 and B3: 20.6, 20.7 and 23.2, respectively). There was substantial inter-reader correlation (r>=0.7) in angle measurements. Conclusion: Our study suggests that glenoid version can be accurately measured at any level between 25%-75%of the glenoid height forWalch B2 and B3 types. We recommend that the glenoid equator be used as the reference in order to assure consistent and reliable version measurements in this group of patients

We present two cases of pseudoaneurysm (PSA) about the shoulder mimicking more common clinical entities-soft tissue neoplasm and septic arthritis-for which biopsy of the mass and joint aspiration were requested respectively. We review the imaging findings of PSA with emphasis on findings in musculoskeletal protocol MRI, including the identification of pulsation artifact in both cases, which was critical to establishing the correct diagnosis. In the proper clinical setting, with imaging findings demonstrating a complex mass or fluid collection, MR images should be scrutinized for the presence of pulsation artifact, which can help diagnose a high-flow vascular lesion and avoid a potentially harmful invasive procedure such as biopsy.