Faculty Bibliography

OBJECTIVES: (1) Assess the association between the B-mode morphologic appearance and elasticity in the rotator cuff tendon using shear wave elastography (SWE). (2) Assess the association between SWE and symptoms. METHODS: Institutional Review Board approval and informed consent were obtained. A retrospective review identified 21 studies in 19 eligible patients for whom SWE was performed during routine sonographic evaluations for shoulder pain. Evaluations were compared with 55 studies from 16 asymptomatic volunteers and 6 patients with asymptomatic contralateral shoulders. Repeated studies were accounted for by resampling. Proximal and distal tendon morphologic characteristics were graded from 1 to 4 (normal to full-thickness tear), and average shear wave velocity (SWV) measurements were obtained at both locations. In 68 examinations, deltoid muscle SWV measurements were available for post hoc analysis. RESULTS: The morphologic grade and SWV showed weak-to-moderate negative correlations in the proximal (P < .001) and distal (P = .002) rotator cuff tendon. A weakly significant SWV decrease was found in the proximal tendon in symptomatic patients (P = .049); no significant difference was seen in the distal tendon. The deltoid muscle SWV showed weak-to-moderate negative correlations with the morphologic grade in the proximal (P = .004) and distal (P = .007) tendon; the deltoid SWV was also significantly lower in symptomatic shoulders (P = .001). CONCLUSIONS: Shear wave elastography shows tendon softening in rotator cuff disease. It captures information not obtained by a morphologic evaluation alone; however, a poor correlation with symptoms suggests that SWE will be less useful in workups for shoulder pain than for preoperative assessments of tendon quality. Deltoid muscle softening seen in morphologically abnormal and symptomatic patients requires further exploration.

The time dependence of the diffusion coefficient is a hallmark of tissue complexity at the micrometer level. Here we demonstrate how biophysical modeling, combined with a specifically tailored diffusion MRI acquisition performing diffusion tensor imaging (DTI) for varying diffusion times, can be used to determine fiber size and membrane permeability of muscle fibers in vivo. We describe the random permeable barrier model (RPBM) and its assumptions, as well as the details of stimulated echo DTI acquisition, signal processing steps, and potential pitfalls. We illustrate the RPBM method on a few pilot examples involving human subjects (previously published as well as new), such as revealing myofiber size derived from RPBM increase after training in a calf muscle, and size decrease with atrophy in shoulder rotator cuff muscle. Finally, we comment on the potential clinical relevance of our results

PURPOSE: To develop an accelerated SEMAC metal implant MRI technique (Sparse-SEMAC) with reduced scan time and improved metal distortion correction. METHODS: Sparse-SEMAC jointly exploits the inherent sparsity along the additional phase-encoding dimension and multicoil encoding capabilities to significantly accelerate data acquisition. A prototype pulse sequence with pseudorandom ky -kz undersampling and an inline image reconstruction was developed for integration in clinical studies. Three patients with hip implants were imaged using the proposed Sparse-SEMAC with eight-fold acceleration and compared with the standard-SEMAC technique used in clinical studies (three-fold GRAPPA acceleration). Measurements were performed with SEMAC-encoding steps (SES) = 15 for Sparse-SEMAC and SES = 9 for Standard-SEMAC using high spatial resolution Proton Density (PD) and lower-resolution STIR acquisitions. Two expert musculoskeletal (MSK) radiologists performed a consensus reading to score image-quality parameters. RESULTS: Sparse-SEMAC enables up to eight-fold acceleration of data acquisition that results in two-fold scan time reductions, compared with Standard-SEMAC, with improved metal artifact correction for patients with hip implants without degrading spatial resolution. CONCLUSION: The high acceleration enabled by Sparse-SEMAC would enable clinically feasible examination times with improved correction of metal distortion. Magn Reson Med, 2016. (c) 2016 Wiley Periodicals, Inc.

Objectives: Proper surgical planning requires accurate and reliable pre-operative patient information. The more comprehensive the data, the more the surgeon can tailor a general surgical technique to an individual patient's unique anatomy. A previous retrospective study demonstrated that three-dimensional magnetic resonance imaging more accurately characterized rotator cuff tears compared to two-dimensional images when checked against intraoperative pictures. The purpose of this study was to determine if three-dimensional MRI imaging would continue to be more accurate than two-dimensional imaging in a prospective study. Methods: Patients were prospectively included if they had a full-thickness primary rotator cuff tear on pre-operative MRI. Intra-op videos were taken from the posterior and lateral portals, with a grasper fully mobilizing the torn tendon in each view. 7 surgeons then reviewed the videos and independently characterized the shape of the tears into crescent, U-shaped tears, L-shaped tears, or massive tears. This was considered the gold-standard. Two musculoskeletal radiologists reviewed the corresponding MRI studies independently and blind to the arthroscopic findings and characterized the shape on the basis of the tear's retraction and size 2D MRI. The 3D reconstructions of each cuff tear were reviewed by each radiologist to characterize the shape. Statistical analysis included 95% confidence intervals and fleiss's kappa. Results: 37 patients were enrolled in the study. Among the 7 surgeons, agreement on cuff tear was 93% ( =.87). The accuracy for differentiating between crescent-shaped, longitudinal, and massive tears using measurements on 2D MRI was 73.4% for reader 1 and 71.2% for reader 2. The accuracy for tear shape characterization into crescent and longitudinal U- or L-shaped using 3D MRI was 92% for reader 1 and 94% for reader 2. When further characterizing the longitudinal tears as massive or not using 3D MRI, both readers had an accuracy of 83%. The overall accuracy of 3D MRI was 91%, significantly different (P=.07) from 2D MRI accuracy (70.4). Conclusion: Our study has demonstrated that 3D MR reconstructions of the rotator cuff improve the accuracy of characterizing rotator cuff tear shapes compared with current 2D MRI-based techniques. (Figure Presented)

AIMS: To evaluate whether an ultra-low-dose CT protocol can diagnose selected limb fractures as well as conventional CT (C-CT). PATIENTS AND METHODS: We prospectively studied 40 consecutive patients with a limb fracture in whom a CT scan was indicated. These were scanned using an ultra-low-dose CT Reduced Effective Dose Using Computed Tomography In Orthopaedic Injury (REDUCTION) protocol. Studies from 16 selected cases were compared with 16 C-CT scans matched for age, gender and type of fracture. Studies were assessed for diagnosis and image quality. Descriptive and reliability statistics were calculated. The total effective radiation dose for each scanned site was compared. RESULTS: The mean estimated effective dose (ED) for the REDUCTION protocol was 0.03 milliSieverts (mSv) and 0.43 mSv (p < 0.005) for C-CT. The sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) of the REDUCTION protocol to detect fractures were 0.98, 0.89, 0.98 and 0.89 respectively when two occult fractures were excluded. Inter- and intra-observer reliability for diagnosis using the REDUCTION protocol (kappa = 0.75, kappa = 0.71) were similar to those of C-CT (kappa = 0.85, kappa = 0.82). Using the REDUCTION protocol, 3D CT reconstructions were equivalent in quality and diagnostic information to those generated by C-CT (kappa = 0.87, kappa = 0.94). CONCLUSION: With a near 14-fold reduction in estimated ED compared with C-CT, the REDUCTION protocol reduces the amount of CT radiation substantially without significant diagnostic decay. It produces images that appear to be comparable with those of C-CT for evaluating fractures of the limbs. Cite this article: Bone Joint J 2016;98-B:1668-73.

There has been a rapid increase in the number of shoulder arthroplasties, including partial or complete humeral head resurfacing, hemiarthroplasty, total shoulder arthroplasty, and reverse total shoulder arthroplasty, performed in the United States over the past two decades. Imaging can play an important role in diagnosing the complications that can occur in the setting of these shoulder arthroplasties. This review is divided into two parts. The first part provides a general discussion of various imaging modalities, comprising radiography, CT, MRI, ultrasound, and nuclear medicine, and their role in providing useful, treatment-guiding information. The second part focuses on the most appropriate imaging algorithms for shoulder arthroplasty complications such as aseptic loosening, infection, fracture, rotator cuff tendon tear, and nerve injury. The evidence-based ACR Appropriateness Criteria guidelines offered in this report were reached via an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (the RAND/UCLA Appropriateness Method and the Grading of Recommendations Assessment, Development, and Evaluation) for rating the appropriateness of imaging and treatment procedures for specific clinical scenarios. Further analysis and review of the guidelines were performed by a multidisciplinary expert panel. In those instances in which there was insufficient or equivocal data for recommending the appropriate imaging algorithm, expert opinion may have supplemented the available evidence.

Purpose: Assess, utilizing MRI, the normal maturation and stress injury to the coracoid process and bipolar growth plate, at the interface with the underlying scapula. To the best of our knowledge this has not yet been described in the literature. Materials and Methods: The study was divided into 2 parts: (A) Maturation of the coracoid process and bipolar growth plate. Retrospective review of 182 consecutive shoulder MRIs in 160 children without clinical or MRI evidence of coracoid pathology (107 boys, 53 girls, ages 0 to <5, n=36, 5 to <10, n = 25, 10 to <15, n = 67, and 15 to 18, n = 54). The studies were reviewed with special attention to the development and fusion of the coracoid to the scapula, via the bipolar growth plate. (B) Growth plate injuries. Retrospective review of shoulder MRIs with coracoid growth plate disturbance (7 boys, 1 girl, mean age 15). Results: (A)Maturation of the coracoid process and bipolar growth plate. At 0 to <5 years the cartilaginous coracoid precursor conformed to the shape of a mature coracoid process, with a small oval primary ossification center within it. The bony margins at the coracoid-scapular interface transformed from smooth to irregular with advancing age. At 5 to <10 years of age, a more distinct, undulating, bipolar growth plate developed. Complete closure of the bipolar plate was observed as early as 11 years of age and was noted in 41 % of patients by age 14 and in 86 % of 15 to 18 year olds. (B) Growth plate injuries. The 8 patients with growth plate stress injuries included 2 patients with neuromuscular disorders and 6 patients with sports related symptoms. The growth plate demonstrated widening, irregularity, and increased signal, with surrounding soft tissue and opposing bony marrow edema and hypertrophy. Conclusion: MRimaging of normal maturation as well as stress injury of the base of the coracoid is crucial for accurate imaging diagnosis. Injury to the base of the coracoid, while uncommon, should be considered when assessing adolescents with shoulder symptomatology

Purpose: To characterize the utility of shoulder imaging in the outpatient setting; Define predictor variables for useful shoulder imaging in terms of guiding the selection of the primary diagnosis and treatment Materials and Methods: We conducted a retrospective review of adult patients over a 32 month period evaluated and imaged for a primary complaint of shoulder pain in one of three outpatient settings: (1) orthopaedics, (2) emergency department [ED], and (3) internal medicine [IM]. Our sample population was chosen through a review of electronic medical records, using shoulder related ICD-9 codes and physician names. The main outcome variable for this study was imaging utility. A useful imaging examination was defined as a study that satisfied at least one of the following 4 criteria: changed the clinical diagnosis, guided a change in treatment selection, provided a final diagnosis, or guided definitive treatment. A utility score was assigned to each study based on the number of criteria satisfied (range 0-4) with a score of 0 defined as no utility, 1 low utility, 2 moderate utility, and score of > 3 high utility. For patients receiving multiple sequential imaging studies during their workup, each study was included and scored separately. The potential predictor variables evaluated for useful imaging included age, gender, trauma history, symptom chronicity, and injury setting (sports vs. non-sports). Statistical analysis included 95 % confidence intervals and binary logistic regression. Results: A total of 122 patients (70 female/52 male; mean age 47 years (range 18-84)) underwent a total of 171 imaging studies (109 radiographs/57 MRIs/3 CT/2 ultrasound) as part of their initial workup. 106 studies were ordered from orthopaedics, 64 from ED, and 1 from IM. CT and ultrasound utility were not assessed due to low number of cases. Overall, 95.9 % of the imaging studies met the minimum criteria for utility, most commonly helping guide the selection of a definitive treatment (71.9 %). 30.4 % of the studies were categorized as moderately useful, while 12.9 % were classified as highly useful. 95.4 % of radiographs met the criteria for utility, the majority of which were categorized as low utility (78.9 %). Both sports related injury history and trauma were predictive of at least moderate utility for radiographs (p = 0.039, p = 0.004). Younger age was a significant predictor of at least moderate utility for radiographs, most commonly in patients under 32 (p=0.003, AUC 0.748). 96.5 % of MRIs met the criteria for utility, the majority of which were categorized as moderate or high utility (84.2 %). None of the variables investigated were found to significantly predict MRI utility. For patients undergoing radiographs and MRI, MRI was found more useful than radiographs in 53 % of patients with an average utility score of 2.1. Equal utility was found in 42 % of cases, while radiographs were found most useful in 5 % of patients. Conclusion: Our study suggests that both radiographs and MRI have utility in the outpatient evaluation of shoulder pain. This serves as a potential first step towards the development of evidence based imaging algorithms that can be used and tested in future studies

Purpose: Examine the accuracy of diagnosing adhesive capsulitis (AC) on MRI, using physical exam and clinical impression of an orthopedic sports clinician as the diagnostic reference standard. Materials and Methods: Retrospective query of our digital database was performed to identify all shoulder MRIs performed at our institution in 2013. The first 100 consecutive subjects aged >40 were included for further review. MRI reports were assessed for the presence of the following information: 1. Thickening of the capsule at the axillary recess (AR), 2. Thickening of the coracohumeral ligament (CHL), 3. Infiltration/ edema of subcoracoid fat, 4. Disproportionate fluid within the proximal biceps tendon sheath, and 5. Imaging impression ofAC. Orthopedic notes were assessed for documented range of shoulder motion and overall clinical impression (10 sports fellowship-trained orthopedic surgeons, 1 shoulder and elbow fellowship-trained orthopedic surgeon, and 1 sports medicine trained primary care physician). Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and overall accuracy were calculated. Fisher exact tests were performed to determine whether each imaging finding was predictive of a positive clinical diagnosis of AC, or likely to predispose to a false positive diagnosis of AC. Results: One hundred shoulder MRI reports in 99 patients were analyzed (59men, 40 women;mean age 58, range 40-87). 17 patients were diagnosed with AC based on imaging findings. Of these patients, frequency of imaging findings included: thickening of the AR (11) or the CHL (8), infiltration of subcoracoid fat (13), and disproportionate fluid in the proximal biceps tendon sheath (3). Six patients had a clinical diagnosis of AC. Fifteen MRIs demonstrated false positive results, while false negative results were seen in 4 cases. The overall sensitivity for theMRI diagnosis of AC was 33.3%with a specificity of 84%. The PPV was 11.8 %,NPV 95.2 %, and overall accuracy 81 %. Fisher exact test P values to determine whether each imaging finding was predictive of a reference standard diagnosis of AC ranged from 0.109 to 1.000. P values to determine whether each imaging finding would lead to a false positive MRI diagnosis were <0.001 for subcoracoid fat infiltration, thickening of the AR, and thickening of the CHL, and p = 1.000 for disproportionate fluid in the biceps tendon sheath. Conclusion: The predictive value of the established MRI findings of adhesive capsulitis may not be as strong as previously shown. Radiologists should be aware of potential imaging over diagnosis and should correlate imaging findings with documented physical exam, when available

Purpose: A routine shoulderMRI protocolwith multi-planar 2D fast spin echo (FSE) sequences usually requires 15-20 min of imaging time.With recent technological advances of multichannel coils and MRI systems, these same sequences can nowbe acquired rapidly using parallel imaging. The purpose of this study was to evaluate if a 5-min shoulder MRI protocol using parallel imaging is interchangeable with a routine shoulder MRI protocol. Materials and Methods: 153 shoulder MRI exams performed on an 8 channel 3 T system (Siemens Verio) with a 4 channel shoulder coil (Invivo) were retrospectively reviewed. All scans included a routine 5 sequence protocol (coronal oblique fat suppressed (fs) PD-weighted and T2-weighted FSE sequences, sagittal oblique fs fluid sensitive and non fs T1-weighted FSE sequences, and an axial fluid sensitive FSE sequence) and 4 fast sequences with an acceleration factor of 2 and slightly larger voxels (coronal oblique, sagittal oblique, and axial fs fluid sensitive sequences and a sagittal oblique non fs T1-weighted sequence). After separation and anonymization of the two protocols, 2 musculoskeletal radiologists independently evaluated the following structures: supraspinatus and infraspinatus tendons (normal/tendinosis, low grade partial-thickness tear, high grade partial-thickness tear, full thickness tear); subscapularis tendon (normal/tendinosis, partial thickness tear, incomplete full thickness tear, and complete full thickness tear); rotator cuff muscle fatty infiltration (none, minimal, mild, moderate, marked); biceps tendon (normal, tendinosis/ partial tear, complete tear); and labrum by quadrant (intact, tear). A test for interchangeability between the fast and routine protocols was performed by comparing the difference between the inter-reader agreement for the routine protocol with the inter-reader agreement when 1 reader was reading the routine protocol and the other reader was reading the fast protocol. Results: The mean age of the patients was 46.75 years (18 - 80) with 85 men and 68 women. The average imaging time was 5 min, 23 s (4:47 - 6:45) for the fast protocol and 14 min, 6 s (12:43 - 16:34) for the routine protocol. The inter-reader agreement for supraspinatus/ infraspinatus pathology was 79.5 % for the routine protocol versus 80.8 % between the routine and fast protocols (95 % CI for difference -5.5 to 2.9 %, p = 0.539). The agreement for subscapularis pathology was 83.4 % for the routine protocol versus 83.4 % between the two protocols (95 % CI -3.8 to 3.8%, p = 1.0). The agreement on muscle fatty infiltration was 89.4 % for the routine protocol versus 91.4 % between the two protocols (95 % CI -4.5 to 0.6 %, p = 0.141). The agreement on biceps pathology was 70.9 % for the routine protocol versus 68.2 % between the two protocols (95 % CI -2.4 to 7.7 %, p = 0.302). The agreement on labrum was between 77.5 and 94.0 % for the routine protocol versus 75.5-93.4 % between the two protocols (95 % CI -3.2 to 6.6 %, p value=0.105-1.0). Conclusion: A 5-min shoulder MRI is clinically interchangeable with a routine shoulderMRI for evaluation of the rotator cuff, biceps tendon and glenoid labrum. Using a 5-min protocol could improve the efficiency and lower the costs of performing a shoulder MRI