Faculty Bibliography

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.

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

Purpose: Preoperative cartilage loss is a predictor of poor outcomes after arthroscopic partial meniscectomy (APM). Previous studies have used time-intensive MRI grading systems, such as MOAKS (MRI OsteoArthritis Knee Score), which are not amenable for routine clinical use. This study's purpose was to test whether cartilage loss graded using MOAKS provides better prediction of outcomes than a simpler clinically used grading system.
Material(s) and Method(s): 80 cases were selected meeting the following criteria: 1. Preoperative knee MRI performed within 6 months of APM surgery 2. Outcomes measured at the time of surgery and 1 year after surgery. Surgical failure was defined as a less than 10 point improvement in the Knee Osteoarthritis Pain Score (KOOSpain). Cases were independently evaluated by 2 musculoskeletal (MSK) radiologists and 1 radiology fellow using MOAKS and a modified Outerbridge grading system used clinically. Accuracy of each system in discriminating success and failure was estimated using area under the ROC (AUC) with 95% confidence intervals (CI).
Result(s): 78 patients (38 females) with mean age of 56.6 years (range of 45-77) were studied. 32 patients (41%) were surgical failures. At least Grade 2 (< 50% cartilage thickness loss) ranged from 8% (lateral tibial plateau) to 26% (medial femoral condyle) of the observations. AUC values of the clinical grading system (range 0.585 - 0.625) were very similar to MOAKS (range 0.553 to 0.667) for all cartilage surfaces and non-inferior to MOAKS in the medial femoral condyle (p = 0.015) and trochlea (p =0.031). The lateral femoral condyle was the only surface where MOAKS (0.667) was significantly higher than the clinical grading system (0.614).
Conclusion(s): Cartilage loss graded usingMOAKS and a simpler clinically used system have similar ability in predicting outcomes after APM. This suggests that it is feasible to use routine clinical grading of cartilage to develop models to predict outcomes after APM

Purpose: To better understand alterations in repaired supraspinatus tendons using a multimodality approach including MRI, assessment of tendon vascularity by power Doppler (PD), and tendon mechanical properties using shear wave elastography (SWE). To investigate whether SWE and PD can provide quantitative assessment of tendon healing following rotator cuff repair.
Material(s) and Method(s): This HIPAA compliant prospective study was approved by the institutional review board with informed consent. Between 9/2013 and 6/2016, twelve patients (7 males, 5 females; mean age 61 years) with unilateral full-thickness supraspinatus tendon tears underwent MRI and ultrasound pre-operatively, 3-months and 6-months post-surgery. The supraspinatus tendon MRI signal intensity, PD and SWE properties were measured. Repaired and asymptomatic shoulders were compared over time within and between modalities.
Result(s): No significant association was seen between mean SWE and MRI signal intensity (non-insertional portion -0.25, p=0.467, insertional portion -0.18, p=0.593), or between PD and MRI signal intensity (non-insertional portion -0.19, p=0.599, insertional portion 0.22, p=0.533) within the supraspinatus tendon. MRI signal intensity and PD within the supraspinatus tendon, both increased and then decreased postoperatively. Shear wave velocities increased throughout the postoperative period in the tendon footprint, while increasing and then decreasing in the distal tendon.
Conclusion(s): MRI and ultrasound parameters did not achieve statistically significant correlation; however, their respective trend behavior suggests that a temporal relationship exists between modali ties. We postul a te that a more detai l ed multiparametric imaging approach and/or comparison with a more selective MR measure, such as T2* values, may be required to evaluate rotator cuff repair

Purpose: To present an automatic humeral head and glenoid segmentation method based on two-dimensional deep convolutional neural networks (CNNs).
Material(s) and Method(s): The study received institutional review board approval. A retrospective dataset of volumetric structural MR images of the shoulder from 100 subjects, including 73 normal cases and 27 cases with a Hill-Sachs lesion and/or anterior glenoid bone loss in the setting of anterior shoulder instability, were manually segmented by experts. A 2D CNN architecture was trained with multiple initial feature maps and layers. Its segmentation performance was then tested against the gold standard of manual segmentation using four-fold cross-validation. The time needed to manually segment each shoulder MRI was documented for each case.
Result(s): Automatic segmentation of the humeral head achieved a mean average precision for object detection of 0.99, a dice similarity score of 0.95, a segmentation precision of 0.95, and recall of 0.95. The Hausdorff distance was 26.9mm, the mean square distance of 0.5mm, and the residual mean square distance of 1.5mm. For the glenoid, automatic segmentation achieved a mean average precision for object detection of 0.92, a dice similarity score of 0.86, a segmentation precision of 0.88, and recall of 0.86. The Hausdorff distance was 20.7mm, themean square distance of 0.8mm, and the residual mean square distance of 1.8mm. On average, the time for manual segmentation ranged between 90 to 120 minutes per imaging study.
Conclusion(s): Using CNNs, we were able to accurately segment the humeral head and glenoid on MRI. Our results serve as an important initial step towards the automatic diagnosis and quantification of Hill-Sachs lesions and glenoid bone loss and determination of on/off track status. This, in turn, has the potential to provide consistently accurate imaging information that can be used to guide the selection of the most appropriate initial treatment for the anterior shoulder instability patient population

PURPOSE/OBJECTIVE:To correlate the histopathologic appearances of resected long head of the biceps tendon (LHBT) specimens following biceps tenodesis, with pre-operative MRI and arthroscopic findings, with attention to the radiologically normal biceps. MATERIAL AND METHODS/METHODS:Retrospective analysis of patients who had undergone preoperative MRI, subsequent arthroscopic subpectoral tenodesis for SLAP tears and histopathologic inspection of the excised sample between 2013 and 16. Those with a normal MRI appearance or mildly increased intrasubstance signal were independently analyzed by 2 blinded radiologists. A blinded orthopedic surgeon and pathologist reviewed all operative imaging and pathologic slides, respectively. RESULTS:Twenty-three LHBT resected samples were identified on MRI as either normal (Reader 1 n = 15; Reader 2 n = 14) or demonstrating low-grade increased signal (Reader 1 n = 8; Reader 2 n = 9). Of these, 86.9% demonstrated a histopathological abnormality. 50% of samples with histopathological abnormality demonstrated normal appearance on MRI. The most common reported histopathology finding was myxoid degeneration (73.9%) and fibrosis (52.2%). The most common arthroscopic abnormality was fraying (18.2%) and erythema (13.6%). Utilizing histopathology as the gold standard, the two radiologists demonstrated a sensitivity of 35.0% v 42.9%, specificity of 66.7% v 100%, PPV of 87.5% v 100%, and NPV of 13.3% v 14.3%. Corresponding arthroscopic inspection demonstrated a sensitivity of 31.6%, specificity of 66.6%, PPV 85.7% and NPV of 13.3%. There was moderate agreement between the two radiologists, κ = 0.534 (95% CI, 0.177 to 0.891), p = 0.01. CONCLUSION/CONCLUSIONS:Histopathological features of low grade tendinosis including mainly myxoid degeneration and fibrosis are frequently occult on MR imaging.

PURPOSE/OBJECTIVE:Characterize the clinical utility of diagnostic shoulder imaging modalities commonly used in the outpatient workup of shoulder pain. MATERIALS/METHODS/METHODS:Retrospective review of adults imaged for outpatient shoulder pain from 1/1/2013 to 9/1/2015. To be categorized as "useful", a study had to meet one of the following criteria: change the clinical diagnosis or treatment plan, provide a final diagnosis, or guide definitive treatment. A utility score was assigned to each study based on the number of utility criteria met (range 0-4). A score of 1 was considered low utility; a score of greater than or equal to 2 was considered high utility. Statistical analysis included binary logistic regression and generalized estimating equations. RESULTS:210 subjects (65% male); mean age 47 (range 18-84), underwent 302 imaging studies (159 X-ray, 137 MRI, 2 CT, 4 ultrasound) during the study period. 92.1% of all studies met minimum criteria for utility (score >1). Most commonly, diagnostic studies obtained during the outpatient workup of shoulder pain were found to guide definitive treatment (70.5%) or provide a final diagnosis (53%). Most X-rays were categorized as no or low utility (85.5%). 97.8% of the MRI studies were categorized as useful with most being high utility (73%). Overall, MRI was the most useful modality in all clinical scenarios (P = 0.002) and more likely to be high utility (P < 0.001) compared to X-rays. None of the investigated patient or injury characteristics were significant predictors of useful imaging. CONCLUSION/CONCLUSIONS:Our study suggests that both radiographs and MRI are useful in the evaluation of adult unilateral shoulder pain in the outpatient setting. MRI appears to be the most useful imaging modality in terms of helping guide diagnosis and treatment selection. This serves as a potential first step towards the development of evidence based imaging algorithms that can be used and tested in future studies.

OBJECTIVE:The purpose of this study is to familiarize the radiologist with knee arthroscopy, including the setup, equipment, and standard procedure used. This is followed by a discussion of the strengths and weaknesses of knee MRI and arthroscopy and presentation of images showing normal knee anatomy and pathologic findings. CONCLUSION/CONCLUSIONS:By having an understanding of basic arthroscopic principles as well as the strengths and limitations of MRI and arthroscopy in the diagnosis of knee abnormalities, radiologists will improve image interpretation and add value to interactions with the consulting orthopedic surgeon.

OBJECTIVE:The purpose of this study is to assess downstream costs associated with pancreatic cysts incidentally detected at MRI. MATERIALS AND METHODS/METHODS:Two hundred patients with an incidental pancreatic cyst detected at MRI were identified. Downstream events (imaging, office visits, endoscopic ultrasound-guided fine-needle aspiration, or chemotherapy) were identified from the electronic medical record. Radiologists' recommendations and ordering physician management were classified relative to the American College of Radiology (ACR) incidental findings committee recommendations. Costs for the downstream events were estimated using national Medicare rates and a 3% annual discount rate. Mean costs were computed. RESULTS:Estimated downstream costs averaged $460 per cyst ($872 per cyst with any follow-up testing). Nine patients had a clinically relevant outcome during follow-up (increase in cyst size, development of new cyst, or development of pancreatic cancer). Downstream cost per cyst with a clinically relevant outcome was $1364. Costs were greater when ordering physicians overmanaged ($842) versus when they were adherent ($631) or undermanaged ($252) relative to radiologist recommendation. Although costs were $252 when ordering physicians undermanaged relative to ACR incidental findings committee recommendations, costs were similar when ordering physicians were adherent ($811) or overmanaged ($845) relative to ACR incidental findings committee recommendations. Costs did not vary significantly according to whether radiologists recommended follow-up testing ($317-$491) or whether radiologist recommendations were adherent, undermanaged, or overmanaged relative to ACR incidental findings committee recommendations ($344-$528). CONCLUSION/CONCLUSIONS:The findings suggest a role for targeted educational efforts, collaborative partnerships, and other initiatives to foster greater adherence to radiologist recommendations, including critical test results notification systems, automated reminders within electronic health systems, and stronger language within radiology reports when no follow-up testing is recommended.

Shoulder pain is one of the most common reasons for musculoskeletal-related physician visits. Imaging plays an important role in identifying the specific cause of atraumatic shoulder pain. This review is divided into two parts. The first part provides a general discussion of various imaging modalities (radiographs, arthrography, nuclear medicine, ultrasound, CT, and MRI) and their usefulness in evaluating atraumatic shoulder pain. The second part focuses on the most appropriate imaging algorithms for specific shoulder conditions including: rotator cuff disorders, labral tear/instability, bursitis, adhesive capsulitis, biceps tendon abnormalities, postoperative rotator cuff tears, and neurogenic pain. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.