Faculty Bibliography

OBJECTIVE: To assess for a difference in the characteriza - tion of rotator cuff (RC) muscle fatty infiltration (FI) between the sagittal and coronal planes in the setting of a large or massive RC tear. MATERIALS AND METHODS: Retrospective review of pa - tients with MRIs demonstrating large or massive RC tears (study group-SG) and no tearing (control group-CG) was conducted. Sagittal T1W and coronal PD images of the supraspinatus and infraspinatus muscles from each patient were selected, separated, and placed in random order. Three MSK readers reviewed the images blindly and independently and qualified the FI based on the Goutallier classification. RESULTS: The SG included 15 men and 15 women (mean age: 65; range: 45 to 87 years); CG included 10 men and 10 women (mean age: 60; range 45 to 76 years). Statistically significant (SS) discrepancies in the assessment of the FI between the sagittal and coronal images occurred 62% in SG and 33% in CG, (p < 0.001). In SG, each reader demon - strated a SS tendency (p < 0.04) to assign a higher value to each muscle when grading the sagittal images compared to coronal images. In SG, 33% of the time (37% supraspinatus, 29% infraspinatus), there was a grade greater than or equal to 3 assigned on the sagittal images but less than 3 grade on corresponding coronal images. CONCLUSION: There was a statistically significant differ - ence in the characterization of RC FI between the sagittal and coronal planes in the setting of a large or massive tear, likely related to incomplete visualization of the musculature on sagittal imaging secondary to muscle and tendon retrac - tion and more complete visualization on coronal imaging. Awareness of this difference may allow for a more accurate characterization of the degree of fatty infiltration.

OBJECTIVE: Recalling a patient to repeat a radiology examination is an adverse and, in certain cases, preventable event. Our objectives were to assess the rate of patient recalls for all imaging performed in the outpatient setting at our institution and to characterize the underlying reasons for the recalls. MATERIALS AND METHODS: We performed a retrospective review of all repeat imaging requests for an inadequate initial imaging study between January 2012 and March 2015. RESULTS: We identified 100 recall requests (mean, 2.6 requests per month), for an overall recall rate of approximately 1 in 8046 ambulatory studies and 1 in 1684 MRI studies. Nearly all recalls (98%) involved adults. A total of 95% of the recalls were for MRI studies. The most common reason for a patient recall request was an incomplete examination, making up 24% of all requests. The other causes were inadequate coverage of the area of interest (22%), protocoling errors (20%), poor imaging quality (15%), additional imaging to clarify a finding (11%), insufficient contrast visualization (7%), and incorrect patient information (1%). CONCLUSION: We found that patient recalls for imaging in the outpatient setting at our institution are not common. When recalls did occur, they were most often related to the acquisition of MR images. Improved technologist education on MRI protocoling and enhanced communication between ordering clinicians and radiologists to clarify the purpose of imaging might reduce the need for repeat ambulatory imaging.

BACKGROUND: The purpose of this study was to see if 3-dimensional (3D) magnetic resonance imaging (MRI) could improve our understanding of rotator cuff tendon tear shapes. We believed that 3D MRI would be more accurate than two-dimensional (2D) MRI for classifying tear shapes. METHODS: We performed a retrospective review of MRI studies of patients with arthroscopically proven full-thickness rotator cuff tears. Two orthopedic surgeons reviewed the information for each case, including scope images, and characterized the shape of the cuff tear into crescent, longitudinal, U- or L-shaped longitudinal, and massive type. 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 using 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 intraclass correlation coefficients. RESULTS: The study reviewed 34 patients. The accuracy for differentiating between crescent-shaped, longitudinal, and massive tears using measurements on 2D MRI was 70.6% for reader 1 and 67.6% for reader 2. The accuracy for tear shape characterization into crescent and longitudinal U- or L-shaped using 3D MRI was 97.1% for reader 1 and 82.4% for reader 2. When further characterizing the longitudinal tears as massive or not using 3D MRI, both readers had an accuracy of 76.9% (10 of 13). The overall accuracy of 3D MRI was 82.4% (56 of 68), significantly different (P = .021) from 2D MRI accuracy (64.7%). 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.

OBJECTIVE: The purpose of this study was to determine whether the simultaneous MRI evaluation of Hill-Sachs lesions and glenoid bone loss by use of the on-track off-track method can be used to predict engagement during arthroscopy. MATERIALS AND METHODS: The records of 75 consecutively registered patients (60 male patients, 15 female patients) with a history of previous anterior shoulder instability who underwent preoperative MRI of the shoulder and arthroscopy at our institution were reviewed. A total of 76 MRI examinations were included. Two readers reviewed the MR images of each patient blindly and independently and used the on-track off-track method to predict engagement. These results were compared with the findings related to engagement seen during arthroscopy, which was performed by one of seven orthopedic surgeons. Statistical analyses included Fisher exact test, logistic regression, ROC analysis, and calculation of intraclass correlation coefficients. RESULTS: Using the on-track off-track technique of reading MR images, the reviewers correctly predicted 13 of the 18 engaging (off-track) lesions (sensitivity, 72.2%). Among the 58 shoulders that did not engage (on-track), they correctly predicted 51 (specificity, 87.9%). Overall, the accuracy of the on-track off-track method was 84.2% with a positive predictive value of 65.0% and negative predictive value of 91.1%. CONCLUSION: Our study showed that the on-track off-track method can be used in MRI to accurately assess the bipolar bone loss seen in patients with anterior shoulder instability for predicting the presence of engaging, or off-track, lesions. This information can be used preoperatively to help guide the type of stabilization procedure performed on patients with anterior shoulder instability.

OBJECTIVE: To see if there is an association between engagement on physical examination (PE) and the location of the Hill-Sachs lesion (HSL) as assessed by the modified biceps angle. MATERIALS AND METHODS: Sixty-two patients with a history of anterior shoulder dislocation, who underwent preoperative MRI and arthroscopy at our institution and were tested for engagement on PE, were collected. Two musculoskeletal radiologists reviewed the MR studies, noting the presence of an HSL and documenting the location of the HSL with the modified biceps angle. Statistical analysis included the Mann-Whitney (MW) test and ROC (receiver-operating characteristic) curve. RESULTS: Of 62 patients, there were 58 males and 4 females with a mean age of 30 (range 18-59 years). Twenty patients demonstrated engagement on PE, while 42 did not. All patients had evidence of an HSL on MRI and arthroscopy. The mean biceps angle for the engaging group was 151.5 +/- 13.9 degrees , and 142.4 +/- 17.3 degrees for the non-engaging group. The biceps angle was statistically significantly higher among patients who had engagement compared to those who did not (p = 0.027). Overall, diagnostic accuracy was highest for a biceps angle >149 degrees , which resulted in a sensitivity of 70 % and specificity of 67 %. CONCLUSION: The modified biceps angle, as measured on MRI, was significantly higher in patients who demonstrated engagement on physical examination than in those who did not. This supports the theory that the location of the Hill-Sachs lesion may play a role in engagement and may be its most important characteristic when determining its significance.

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

Purpose: To evaluate whether there is a correlation between T2/T2* mapping and ultrasound elastography measurements in the supraspinatus tendon. Materials and Methods: Seven shoulders in 6 patients (2 males/4 females; mean age 60.7 years/range 44-72 years) clinically suspected of having rotator cuff pathology underwent shoulder MR imaging, including coronal, sagittal, and axial fat suppressed T2W and sagittal T1W sequences, with the addition of T2 and T2* mapping sequences. The T2 mapping sequence consisted of 2D multi-echo SE sequence with 5 echoes (TR/TE =1000/9.9 ms/DELTATE = 9.9 ms/FA 180degree/b andwidth = 337 Hz/px/ FOV= 128 mm/resolution = 0.5 x 0.5 x 3.0 mm³), while the T2* mapping sequence consisted of 2D multi-echo spoiled GRE sequence with 6 echoes (TR/TE = 428/3.01 ms/DELTATE = 6.33 ms/FA 60degree/bandwidth = 480 Hz/px/ resolution = 0.5 x 0.5 x 3.0 mm3). SNR was estimated using the background ROI method and corrected with the background Rayleigh distribution. T2/T2* maps were constructed inline by using pixelwise monoexponential fit with nonnegative least squares provided by the vendor (MapIt). The anteroposterior (AP) extent, degree of retraction, and percent thickness of tendon tearing, as well as the Goutallier grade of fatty degeneration of the supraspinatus/infraspinatus musculature were measured on the conventional MRI sequences. Each shoulder then underwent ultrasound that included elastography (USE), derived from acoustic radiation force impulse pulses produced by a 9 MHz transducer. Ultrasound shear-wave-velocities (SWV) were obtained in multiple ROIs drawn within the insertional 1-2 cm of the supraspinatus tendon at the mid-portion of the greater tuberosity superior facet using specialized built-in software. ROIs were organized, and averaged when necessary, into three equidistant groups, medial, middle, and lateral, corresponding to their location relative to the tendon insertion. T2 and T2* values were calculated from the T2 and T2* maps using three equidistant ROIs corresponding to the same medial, middle, and lateral locations as on the USE. Statistical analysis included Pearson correlation coefficients (r). Results: Average SNR in the supraspinatus tendon was 26.8 in the T2W images and 59.2 in the T2*W images. Five shoulders had full-thickness supraspinatus tendon tears with mean retraction of 26 mm and AP extent of 21.4 mm, one shoulder had a non-retracted partial-thickness tear involving less than 50 % of the tendon thickness, and one had tendinosis without a tear. All shoulders had Goutallier grade 1-2 fatty degeneration of the supraspinatus/infraspinatus musculature. The mean +/- standard deviation of the values across all ROIs were 9.4 +/- 2.8 m/s for the SWVon USE, 35.2 +/- 9.3 ms on T2 maps, and 21.3 +/- 3.9 ms on T2* maps. There was strong negative correlation between T2* and SWV values when comparing both lateral ROI's (r=-0.92/p = 0.03) and mean of all three ROI locations (r = -0.90/p = 0.04). There was also strong correlation between T2 values and degree of supraspinatus tendon retraction when comparing the mean of all three ROIs (r = 0.79/p=0.03). Conclusion: There may be an association between T2* values measured on MRI and shear wave velocities measured on ultrasound in the degenerated supraspinatus tendon. This has the potential to provide more quantitative information on tendon quality in terms of elasticity on MRI, and, in turn,more clinically useful information to the orthopaedic surgeon planning rotator cuff repair