Ultrasound-MRI Correlation for Healing of Rotator Cuff Repairs Using Power Doppler, Sonographic Shear Wave Elastography and MR Signal Characteristics: A Pilot Study
OBJECTIVE:To determine whether the healing response in rotator cuff repairs can be quantitatively characterized using a multimodality imaging approach with MR signal intensity, power Doppler and shear wave elastography (SWE). MATERIALS AND METHODS/METHODS:Patients scheduled for rotator cuff repair were prospectively enrolled between September 2013 and June 2016. A 12 patient cohort with unilateral, full-thickness, supraspinatus tendon tears underwent MRI and ultrasound both preoperatively and postoperatively (at 3 and 6 months post-surgery). The MR signal intensity ratio of tendon-to-deltoid muscle (TMR), vascularity score by power Doppler (PD) and shear wave velocity (SWV) were measured. Repaired and asymptomatic control shoulders were compared over time and between modalities. RESULTS:TMR and vascularity of the tendon repair initially increased and then decreased postoperatively. Although not achieving statistical significance, postoperative SWV initially decreased and later increased, which negatively correlated with the TMR at 3 months (r = -0.73, p = 0.005). PD demonstrated a statistically significant change in tendon vascularity over time compared to the contralateral control (p = 0.009 at 3 months; p = 0.036 at 6 months). No significant correlation occurred between TMR and SWE at 6 months, or with PD at any time point. CONCLUSION/CONCLUSIONS:Despite a small patient cohort, this prospective pilot study suggests a temporal relationship of MRI and ultrasound parameters that parallels the expected phases of healing in the repaired rotator cuff.
Does Magnetic Resonance Imaging After Diagnostic Ultrasound for Soft Tissue Masses Change Clinical Management?
OBJECTIVES/OBJECTIVE:To evaluate whether a follow-up magnetic resonance imaging (MRI) scan performed after initial ultrasound (US) to evaluate soft tissue mass (STM) lesions of the musculoskeletal system provides additional radiologic diagnostic information and alters clinical management. METHODS:A retrospective chart review was performed of patients undergoing initial US evaluations of STMs of the axial or appendicular skeleton between November 2012 and March 2019. Patients who underwent US examinations followed by MRI for the evaluation of STM lesions were identified. For inclusion, the subsequent pathologic correlation was required from either a surgical or image-guided biopsy. Imaging studies with pathologic correlations were then reviewed by 3 musculoskeletal radiologists, who were blinded to the pathologic diagnoses. The diagnostic utility of MRI was then assessed on the basis of a 5-point grading scale, and inter-reader agreements were determined by the Fleiss Îº statistic. RESULTS:Ninety-two patients underwent MRI after US for STM evaluations. Final pathologic results were available in 42 cases. Samples were obtained by surgical excision or open biopsy (n = 34) or US-guided core biopsy (n = 8). The most common pathologic diagnoses were nerve sheath tumors (n = 9), lipomas (n = 5), and leiomyomas (n = 5). Imaging review showed that the subsequent MRI did not change the working diagnosis in 73% of cases, and the subsequent MRI was not considered to narrow the differential diagnosis in 68% of cases. There was slight inter-reader agreement for the diagnostic utility of MRI among individual cases (Îº = 0.10) between the 3 readers. CONCLUSIONS:The recommendation of MRI to further evaluate STM lesions seen with US frequently fails to change the working diagnosis or provide significant diagnostic utility.
The Femoroacetabular Impingement Resection (FAIR) Arc: An Intraoperative Aid for Assessing Bony Resection During Hip Arthroscopy
Symptomatic femoroacetabular impingement is one of the most common hip pathologies in young athletes. Intraoperative fluoroscopy is commonly used during hip arthroscopy to aid with portal placement and resection of the cam and pincer lesions. However, there are currently no universally agreed-on tools to allow for the assessment of adequacy of femoral and acetabular osteoplasty. Despite the general lack of consensus among hip arthroscopists, the senior author recommends using the femoroacetabular impingement resection arc to guide the adequacy of cam and pincer resection in hip arthroscopy. Using intraoperative fluoroscopy, one should aim to create a continuous "Shenton's line"-type arc along the inferior aspect of the anterior-inferior iliac spine and superolateral femoral neck base by resecting any bone that causes a break in the continuity of this arc.
Generalized Joint Hypermobility Is Associated With Decreased Hip Labrum Width: A Magnetic Resonance Imaging-Based Study
Purpose/UNASSIGNED:To explore the relationship between generalized joint hypermobility and hip labrum width. Methods/UNASSIGNED:and Fisher exact testing as well as linear regression. Results/UNASSIGNED:Â = .004). Conclusions/UNASSIGNED:Patients with a BTS â‰¥4 were found to have significantly thinner labra than those with a BTS of <4. Level of Evidence/UNASSIGNED:III, retrospective comparative trial.
Imaging Spectrum of Calvarial Abnormalities
Calvarial abnormalities are usually discovered incidentally on radiologic studies or less commonly manifest with symptoms. This narrative review describes the imaging spectrum of the abnormal calvaria. The extent, multiplicity, and other imaging features of calvarial abnormalities can be combined with the clinical information to establish a final diagnosis or at least narrow the differential considerations. Prior trauma (congenital depression, leptomeningeal cysts, posttraumatic osteolysis), surgical intervention (flap osteonecrosis and burr holes), infection, and inflammatory processes (sarcoidosis) can result in focal bone loss, which may also be seen with idiopathic disorders without (bilateral parietal thinning and Gorham disease) or with (Parry-Romberg syndrome) atrophy of the overlying soft tissues. Anatomic variants (arachnoid granulations, venous lakes, parietal foramina) and certain congenital lesions (epidermoid and dermoid cysts, atretic encephalocele, sinus pericranii, and aplasia cutis congenita) manifest as solitary lytic lesions. Other congenital entities (lacunar skull and dysplasia) display a diffuse pattern of skull involvement. Several benign and malignant primary bone tumors involve the calvaria and manifest as lytic, sclerotic, mixed lytic and sclerotic, or thinning lesions, whereas multifocal disease is mainly due to hematologic or secondary malignancies. Metabolic disorders such as rickets, hyperparathyroidism, renal osteodystrophy, acromegaly, and Paget disease involve the calvaria in a more diffuse pattern. Online supplemental material is available for this article. Â©RSNA, 2021.
Improved Functional Outcome Scores Associated with Greater Reduction in Cam Height Using the Femoroacetabular Impingement Resection Arc During Hip Arthroscopy
PURPOSE/OBJECTIVE:To evaluate the association between postoperative cam lesion measured by the "femoroacetabular impingement resection (FAIR) arc" and 2-year patient outcomes following hip arthroscopy. METHODS:A retrospective review of prospectively gathered data from 2013-2017 was performed. All patients who underwent hip arthroscopy for FAI with â‰¥ 2-year follow-up were included. Cam FAIR arc measurements were made pre and postoperatively on a 45Â° Dunn view radiograph. The clinical effect of postoperative cam maximal radial distance (MRD) was assessed using the modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS). Patients were divided into subgroups based on relationship to the mean and standard deviations for cam MRD. One half standard deviation above the mean was found to be 3.15 mm. RESULTS:=0.004). Subgroup analysis demonstrated that patients in the cam MRD < 3.15 mm group had significantly higher mHHS (89.7 vs 70.0 p<0.001) and NAHS scores (90.5 vs 72.9, p<0.001) than those in the >3.15 mm group. Additionally, more patients in the <3.15 mm group reached the minimal clinically important difference (MCID) (95.2% vs 78.9%, p=0.048) and were above patient acceptable symptomatic state (PASS) (95.2% vs 52.6%, p<0.001) compared to the >3.15 mm group. CONCLUSION/CONCLUSIONS:Patients with a lower postoperative cam MRD relative to the FAIR arc demonstrated significantly improved outcomes as compared to those with higher postoperative MRD at two-year follow-up.
The Limited Reliability of Physical Examination and Imaging for Diagnosis of Iliopsoas Tendinitis
PURPOSE/OBJECTIVE:To determine if any association exists between physical examination and/or imaging findings [ultrasound (US) and magnetic resonance imaging (MRI)] and IPT in order to characterize the reliability of these diagnostic modalities. METHODS:Patients who had undergone US-guided iliopsoas tendon sheath injection (of lidocaine and a corticosteroid agent) as well as MRI performed within one year of injection between 2014-2019 were retrospectively reviewed. Demographic data, response to physical exam maneuvers, and response to injection were queried from patient records. US and MRIs were reviewed by 2 independent musculoskeletal-trained radiologists. Response to injection was considered positive if the patient improved by >2 points on a 0-10 VAS score. Chi-square and Fischer exact testing was utilized to assess for any associations. Sensitivities, specificities, positive predictive values, and negative predictive values were calculated. RESULTS:Sixty-three patients, with mean age 52.3 years +/- 17.3, with average BMI 27.4 +/- 4.3, and average follow-up was 33.6 months +/- 20.6 met inclusion criteria. No physical exam maneuvers, sonographic features, or MRI findings were significantly associated with response to iliopsoas tendon injection (p>0.05). Groin pain had a sensitivity of 100%, though a specificity of 7%. Snapping hip had a specificity of 82%, though a sensitivity of 24%. Pain with resisted SLR (sensitivity 62%, specificity 25%), and weakness with resisted SLR (sensitivity 15%, specificity 71%) both were non-reliable. Sonographic bursal distension and tendinosis had low sensitivities (67% and 63%, respectively) and specificities (35% and 32%, respectively). Bursal distension on MRI had sensitivity and specificity of 64% and 45% respectively. Tendon thickening had sensitivity and specificity of 55% and 60%, respectively, while heterogeneity had sensitivity and specificity of 52% and 65%, respectively. CONCLUSION/CONCLUSIONS:Neither physical examination, nor US, nor MRI findings were associated with a positive response to peritendinous iliopsoas corticosteroid injections in patients with suspected IPT.
Distance of the Posterior Interosseous Nerve From the Bicipital (Radial) Tuberosity at Varying Positions of Forearm Rotation: A Magnetic Resonance Imaging Study With Clinical Implications
BACKGROUND:The proximity of the posterior interosseous nerve (PIN) to the bicipital tuberosity is clinically important in the increasingly popular anterior single-incision technique for distal biceps tendon repair. Maximal forearm supination is recommended during tendon reinsertion from the anterior approach to ensure the maximum protective distance of the PIN from the bicipital tuberosity. PURPOSE:To compare the location of the PIN on magnetic resonance imaging (MRI) relative to bicortical drill pin instrumentation for suspensory button fixation via the anterior single-incision approach in varying positions of forearm rotation. STUDY DESIGN:Descriptive laboratory study. METHODS:Axial, non-fat suppressed, T1-weighted MRI scans of the elbow were obtained in positions of maximal supination, neutral, and maximal pronation in 13 skeletally mature individuals. Distances were measured from the PIN to (1) the simulated path of an entering guidewire (GWE-PIN) and (2) the cortical starting point of the guidewire on the bicipital tuberosity (CSP-PIN) achievable from the single-incision approach. To radiographically define the location of the nerve relative to constant landmarks, measurements were also made from the PIN to (3) the prominent-most point on the bicipital tuberosity (BTP-PIN) and (4) a perpendicular plane trajectory from the bicipital tuberosity exiting the opposing radial cortex (PPT-PIN). All measurements were subsequently compared between positions of pronation, neutral, and supination. In supination only, BTP-PIN and PPT-PIN measurements were made and compared at 3 sequential axial levels to evaluate the longitudinal course of the nerve relative to the bicipital tuberosity. RESULTS:< .001). CONCLUSION:This MRI study supports existing evidence that supination protects the PIN from the entering guidewire instrumentation during anterior, single-incision biceps tendon repair using cortical button fixation. The distances between the entering guidewire trajectory and PIN show that guidewire-inflicted injury to the nerve is unlikely during the anterior single-incision approach. CLINICAL RELEVANCE:When a safe technique is used, PIN injuries during anterior repair are likely the result of aberrant retractor placement, and we recommend against the use of retractors deep to the radial neck. Guidewire placement as close as possible to the anatomic footprint of the biceps tendon is safe from the anterior approach. MRI evaluation confirms that ulnar and proximal guidewire trajectory is the safest technique when using single-incision bicortical suspensory button fixation.
Decreased Hip Labral Width Measured via Preoperative MRI is Associated with Inferior Outcomes for Arthroscopic Labral Repair for Femoroacetabular Impingement
PURPOSE/OBJECTIVE:To determine the association between labral width as measured on preoperative MRI with hip-specific validated patient self-reported outcomes at a minimum of 2 years follow-up. METHODS:An IRB-approved retrospective review of prospectively gathered hip arthroscopy patients from 2010 to 2017 was performed. Inclusion criteria was defined as patients >18 years old with radiographic evidence of femoroacetabular impingement who underwent a primary labral repair and had a minimum of 2 years clinical follow-up. Exclusion criteria was defined as inadequate preoperative imaging, prior hip surgery, Tonnis grade â‰¥2 or lateral central edge angle <25 degrees. An a-priori power analysis was performed. MRI measurements of labral width were conducted by two blinded, musculoskeletal fellowship-trained radiologists at standardized "clockface" locations using a previously validated technique. Outcomes were assessed using the Harris Hip Score (HHS), Modified HHS (mHSS), and NonArthritic Hip Score (NAHS). For mHHS, a minimal clinically important difference (MCID) and Patient Acceptable Symptomatic State (PASS) of 8 and 74 were used, respectively. Patients were divided into groups by labral width of < (hypoplastic) and â‰¥ 1 standard deviation below the mean. Statistical analysis was performed using linear and polynomial regression, Mann-Whitney U, chi-square, Fischer exact, and interclass-correlation coefficients (ICC) testing. RESULTS:=0.26, p<0.001). CONCLUSION/CONCLUSIONS:Hip labral width < 1 standard deviation below the mean measured via preoperative MRI was associated with significantly worse functional outcomes following arthroscopic labral repair and treatment of FAI. The negative relationship between labral width and outcomes may be non-linear.
Artificial Intelligence for Classification of Soft-Tissue Masses at US
Purpose/UNASSIGNED:To train convolutional neural network (CNN) models to classify benign and malignant soft-tissue masses at US and to differentiate three commonly observed benign masses. Materials and Methods/UNASSIGNED:= 227) were used to train and evaluate a CNN model to distinguish malignant and benign lesions. Twenty percent of cases were withheld as a test dataset, and the remaining cases were used to train the model with a 75%-25% training-validation split and fourfold cross-validation. Performance of the model was compared with retrospective interpretation of the same dataset by two experienced musculoskeletal radiologists, blinded to clinical history. A second group of US images from 275 of the 419 patients containing the three common benign masses was used to train and evaluate a separate model to differentiate between the masses. The models were trained on the Keras machine learning platform (version 2.3.1), with a modified pretrained VGG16 network. Performance metrics of the model and of the radiologists were compared by using the McNemar test, and 95% CIs for performance metrics were estimated by using the Clopper-Pearson method (accuracy, recall, specificity, and precision) and the DeLong method (area under the receiver operating characteristic curve). Results/UNASSIGNED:The model trained to classify malignant and benign masses demonstrated an accuracy of 79% (95% CI: 68, 88) on the test data, with an area under the receiver operating characteristic curve of 0.91 (95% CI: 0.84, 0.98), matching the performance of two expert readers. Performance of the model distinguishing three benign masses was lower, with an accuracy of 71% (95% CI: 61, 80) on the test data. Conclusion/UNASSIGNED:The trained CNN was capable of differentiating between benign and malignant soft-tissue masses depicted on US images, with performance matching that of two experienced musculoskeletal radiologists.Â© RSNA, 2020.