Faculty Bibliography

The Society of Skeletal Radiology (SSR) Practice Guidelines and Technical Standards Committee identified musculoskeletal infection as a White Paper topic, and selected a Committee, tasked with developing a consensus on nomenclature for MRI of musculoskeletal infection outside the spine. The objective of the White Paper was to critically assess the literature and propose standardized terminology for imaging findings of infection on MRI, in order to improve both communication with clinical colleagues and patient care.A definition was proposed for each term; debate followed, and the committee reached consensus. Potential controversies were raised, with formulated recommendations. The committee arrived at consensus definitions for cellulitis, soft tissue abscess, and necrotizing infection, while discouraging the nonspecific term phlegmon. For bone infection, the term osteitis is not useful; the panel recommends using terms that describe the likelihood of osteomyelitis in cases where definitive signal changes are lacking. The work was presented virtually to SSR members, who had the opportunity for review and modification prior to submission for publication.

BACKGROUND:There is a paucity of literature describing MRI patterns of high ankle sprains in pediatric patients. Radiologists should understand MRI patterns of these injuries in both adults and children. OBJECTIVE:To describe normal MRI appearance of pediatric syndesmotic ligaments and compare MRI patterns of high ankle sprains in children versus adults. MATERIALS AND METHODS/METHODS:We reviewed consecutive ankle MRIs performed over 3 years and divided them into three cohorts: a normal pediatric (≤16 years) cohort, and pediatric and adult cohorts with acute/subacute ankle syndesmosis injuries. Our retrospective review assessed interobserver agreement (Cohen kappa coefficient) and normal pediatric syndesmotic anatomy. We compared patterns of high ankle sprains (Fisher exact test) including ligament tears, periosteal stripping, avulsions and fractures. RESULTS:Of the 582 ankle MRIs, we included 25 in the normal pediatric cohort, 20 in the pediatric injury cohort and 23 in the adult injury cohort. The anterior and posterior tibiofibular ligaments all attached to cortex or cartilaginous precursor, while the interosseous ligament/membrane complex attached to the fibrous periosteum in 22/25 (88%) normal pediatric cases. Tibial periosteal stripping at the interosseous ligament/membrane complex attachment occurred in 7/20 (35%) pediatric and 1/23 (4%) adult injury cases (P=0.02). No other statistically significant differences were found. Interobserver agreement ranged from kappa=0.46 to kappa=0.82 (ligament tears), 0.38 to 0.45 (avulsions) and 0.69 to 0.77 (periosteal stripping). CONCLUSION/CONCLUSIONS:The normal interosseous ligament/membrane complex typically attaches to fibrous periosteum rather than bony cortex. Tibial periosteal stripping, usually without tibial fracture, is significantly more common among pediatric high ankle sprains. MRI patterns of high ankle sprains are otherwise not significantly different between children and adults.

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 κ 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 (κ = 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.

OBJECTIVE:The purpose of the current study is to evaluate the clinical and radiographic outcomes at early to midterm follow-up between fresh precut cores versus hemi-condylar osteochondral allograft (OCAs) in the treatment of symptomatic osteochondral lesions. DESIGN/METHODS:A retrospective review of patients who underwent an OCA was performed. Patient matching between those with OCA harvested from an allograft condyle/patella or a fresh precut allograft core was performed to generate 2 comparable groups. The cartilage at the graft site was assessed with use of a modified Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring system and patient-reported outcomes were collected. RESULTS:= 0.93). CONCLUSIONS:This study found that there was no difference in patient-reported clinical outcomes or MOCART scores following OCA implantation using fresh precut OCA cores or size matched condylar grafts at early to midterm follow-up.

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. ^©RSNA, 2021.

BACKGROUND:Sacroiliitis is an inflammatory arthritis of the sacroiliac joints and is associated with inflammatory bowel disease (IBD). Yet, sacroiliitis often goes undiagnosed in IBD, and the clinical association between IBD disease activity and sacroiliitis is not well established. Patients with Crohn's disease (CD) often receive magnetic resonance enterography (MRE) to assess disease activity, affording clinicians the opportunity to evaluate for the presence of sacroiliitis. We aimed to identify the prevalence and disease characteristics associated with sacroiliitis in CD patients undergoing MRE. METHODS:All CD patients undergoing MRE for any indication between 2014 and 2018 at an IBD referral center were identified. The MREs were reviewed for the presence of sacroiliitis based on bone marrow edema (BME) and structural lesions. We analyzed demographics, IBD characteristics, clinical and endoscopic disease activity, and management between CD patients with and without sacroiliitis. RESULTS:Two hundred fifty-eight patients with CD underwent MRE during the study period. Overall, 17% of patients had MR evidence of sacroiliitis, of whom 73% demonstrated bone marrow edema. Female gender, back pain, and later age of CD diagnosis were associated with sacroiliitis (P = 0.05, P < 0.001, P = 0.04, respectively). Disease location and CD therapy were not associated with sacroiliitis on MRE. Clinical, endoscopic, and radiographic disease activity were not associated with sacroiliitis on MRE. CONCLUSION/CONCLUSIONS:Sacroiliitis is a common comorbid condition in CD. With limited clinical clues and disease characteristics to suggest sacroiliitis, physicians may utilize MRE to identify sacroiliitis, especially in CD patients with back pain.

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.

Background: Literature on glenohumeral dislocations has focused on younger patient populations due to high recurrence rates. However, the spectrum of injuries sustained in younger versus older patient populations is reported to be quite different. Objective: To describe MRI findings and management of anterior shoulder instability in the aging (≥60 years) population. Methods: Shoulder MRIs of anterior glenohumeral dislocators aged ≥40 were subdivided into <60 or ≥60 age groups, and reviewed by two musculoskeletal radiologists for: Hill-Sachs lesion, other fracture, glenoid injury, capsulolabral injury, rotator cuff tear, muscle atrophy, and axillary nerve injury. Fischer exact and logistic regression evaluated for significant differences between cohorts, and inter-reader agreement was assessed. Surgical management was recorded, if available. Results: 104 shoulder MRIs (40-79 years, mean=58.3, 52 females, 52 males) were reviewed (N=54 age <60, N=50 age ≥60). Acute high-grade or full-thickness supraspinatus (64.0% vs. 37.0%, p=0.001), infraspinatus (28.0% vs. 14.8%, p=0.028), and subscapularis tears (22.0% vs. 3.7%, p=0.003) were more common in the ≥60 group. Hill-Sachs lesions were more common in the <60 group (81.5% vs. 62.0%, p=0.046). Greater tuberosity fractures were seen in 15.3% of the overall cohort, coracoid fractures in 4.8%, and axillary nerve injuries in 16.3%. Inter-reader concordance was 88.5-89.4% for rotator cuff tears, and 89.4-97.1% for osseous injury. The <60 group had rotator cuff repair in 11/37 subjects (29.7%), and labral repair in 11/37 (29.7%), while the ≥60 group underwent rotator cuff repair in 17/36 (47.2%), reverse shoulder arthroplasty in 6/36 (16.7%), and labral repair in 6/36 (16.7%). Conclusion: Radiologists should have a high index of suspicion for acute rotator cuff tears in anterior shoulder instability, especially in aging populations. Greater tuberosity or coracoid fractures and axillary nerve injury occur across all ages, while Hill-Sachs injuries are more common in younger patients. Clinical Impact: Acute, high-grade or full-thickness rotator cuff tears are seen with higher frequency in older populations after anterior glenohumeral dislocation in the elderly. Osseous and nerve injuries are important causes of patient morbidity that, if not carefully sought out, may be overlooked by the interpreting radiologist on routine imaging.

PURPOSE/OBJECTIVE:With clinical volumes decreased, radiologists volunteered to participate virtually in daily clinical rounds and provide communication between frontline physicians and patients with coronavirus disease 2019 (COVID-19) and their families affected by restrictive hospital visitation policies. The purpose of this survey-based assessment was to demonstrate the beneficial effects of radiologist engagement during this pandemic and potentially in future crises if needed. METHODS:After the program's completion, a survey consisting of 13 multiple-choice and open-ended questions was distributed to the 69 radiologists who volunteered for a minimum of 7 days. The survey focused on how the experience would change future practice, the nature of interaction with medical students, and the motivation for volunteering. The electronic medical record system identified the patients who tested positive for or were suspected of having COVID-19 and the number of notes documenting family communication. RESULTS:In all, 69 radiologists signed or cosigned 7,027 notes. Of the 69 radiologists, 60 (87.0%) responded to the survey. All found the experience increased their understanding of COVID-19 and its effect on the health care system. Overall, 59.6% agreed that participation would result in future change in communication with patients and their families. Nearly all (98.1%) who worked with medical students agreed that their experience with medical students was rewarding. A majority (82.7%) chose to participate as a way to provide service to the patient population. CONCLUSION/CONCLUSIONS:This program provided support to frontline inpatient teams while also positively affecting the radiologist participants. If a similar situation arises in the future, this communication tool could be redeployed, especially with the collaboration of medical students.