Return to Play Following Concussion: Role for Imaging?

This review surveys concussion management, focusing on the use of neuroimaging techniques in return to play (RTP) decisions. Clinical assessments traditionally were the foundation of concussion diagnoses. However, their subjective nature prompted an exploration of neuroimaging modalities to enhance diagnosis and management. Magnetic resonance spectroscopy provides information about metabolic changes and alterations in the absence of structural abnormalities. Diffusion tensor imaging uncovers microstructural changes in white matter. Functional magnetic resonance imaging assesses neuronal activity to reveal changes in cognitive and sensorimotor functions. Positron emission tomography can assess metabolic disturbances using radiotracers, offering insight into the long-term effects of concussions. Vestibulo-ocular dysfunction screening and eye tracking assess vestibular and oculomotor function. Although these neuroimaging techniques demonstrate promise, continued research and standardization are needed before they can be integrated into the clinical setting. This review emphasizes the potential for neuroimaging in enhancing the accuracy of concussion diagnosis and guiding RTP decisions.

Bone Bruise versus Fracture on MRI and the Relevance to Return to Play.

We review the spectrum of acute osseous injuries in athletes, ranging from osseous contusion (bone bruise) injuries to nondisplaced cortical fractures. The basic biomechanical concepts, underlying histopathologic changes, and characteristic magnetic resonance imaging (MRI) features of acute osseous injuries are presented. Bone bruise injuries of varying severity are highlighted to showcase the breadth of imaging findings on MRI and methods for characterizing such lesions. We emphasize the importance of accurately assessing patterns of injury on MRI to communicate more effectively with team medical staff and recognize the implications on return to play. This article offers the foundational tools for approaching bone bruise injuries in elite athletes to add value to the diagnosis and treatment of this unique patient population.

Synchronous Low-Grade Central Osteosarcoma and Ewing Sarcoma: A Rare Case Report.

A 23-year-old female patient presented with radicular back pain, perineal numbness, and urinary retention. The patient was diagnosed with cauda equina syndrome and magnetic resonance imaging (MRI) of the spine revealed an enhancing osseous lumbar lesion causing severe central stenosis. A core needle biopsy of the lumbar spine showed microscopic features compatible with a small round blue cell tumor. CD99 and FLI1 were positive in the tumor cells. Next-generation sequencing demonstrated a EWSR1::FLI1 fusion. Given these findings, the spine lesion was diagnosed as Ewing sarcoma. The patient underwent surgical decompression of L2. On further workup, an MRI revealed an ill-defined enhancing mass of the right distal femur. This area was biopsied, demonstrating a fibro-osseous lesion with osteoblast proliferation containing nuclear atypia, low mitotic activity, and SATB2 positivity, diagnosed as low-grade central osteosarcoma (LGCOS). The patient underwent resection, which showed a classic LGCOS by histomorphology. Although fluorescence in-situ hybridization study for MDM2 gene amplification was negative, the overall findings are most consistent with LGCOS. These neoplasms are considered to be synchronous due to the presentation of each entity within 6 months. Considering the aggregate yearly incidence of Ewing sarcoma (approximately 1 case per 750 000 per year) and LGCOS (approximately 1 case per 10 million per year), the aggregate yearly probability of developing both of these genetically unrelated tumors in a single individual is 1 per 7.5 trillion per year, and it is likely such an event has never happened in the past.

Deep Learning-Assisted Identification of Femoroacetabular Impingement (FAI) on Routine Pelvic Radiographs.

To use a novel deep learning system to localize the hip joints and detect findings of cam-type femoroacetabular impingement (FAI). A retrospective search of hip/pelvis radiographs obtained in patients to evaluate for FAI yielded 3050 total studies. Each hip was classified separately by the original interpreting radiologist in the following manner: 724 hips had severe cam-type FAI morphology, 962 moderate cam-type FAI morphology, 846 mild cam-type FAI morphology, and 518 hips were normal. The anteroposterior (AP) view from each study was anonymized and extracted. After localization of the hip joints by a novel convolutional neural network (CNN) based on the focal loss principle, a second CNN classified the images of the hip as cam positive, or no FAI. Accuracy was 74% for diagnosing normal vs. abnormal cam-type FAI morphology, with aggregate sensitivity and specificity of 0.821 and 0.669, respectively, at the chosen operating point. The aggregate AUC was 0.736. A deep learning system can be applied to detect FAI-related changes on single view pelvic radiographs. Deep learning is useful for quickly identifying and categorizing pathology on imaging, which may aid the interpreting radiologist.

Bone bruise vs. non-displaced fracture on MRI: a novel grading system for predicting return-to-play.

OBJECTIVE: To devise an MRI grading scheme for osseous contusion patterns in elite hockey players for predicting return-to-play (RTP). METHODS: A retrospective review was performed to identify traumatic lower extremity osseous injuries in professional hockey players. A total of 28 injuries (17 players) were identified over a 10-year period. All had MRIs acquired at ≥ 1.5 T within a mean interval of 2 days from initial injury. MRIs were retrospectively reviewed by 3 musculoskeletal radiologists for osseous contusion pattern, classified as grade 1 (mild), 2 (moderate), or 3 (severe). Grade 3 contusions were further subdivided by the presence or absence of fracture, defined as discrete cortical disruption on MRI or follow-up CT. RTP was calculated from date of injury to next game played based on game log data. Statistical analysis was performed using ANOVA and post hoc unpaired t test. RESULTS: Mean RTP for grade 1, 2, and 3 injuries was 2.8, 4.5, and 20.3 days, respectively. Grade 3 injuries without and with cortical fractures had mean RTP of 18.3 and 21.4 days, respectively. ANOVA analysis between groups achieved statistical significance (p < 0.001). Post hoc t test demonstrated statistically significant differences between grade 3 and grades 1 (p < 0.001) and 2 (p < 0.001) injuries. There was no statistical difference in RTP between grade 3 subgroups without and with fracture (p = 0.327). CONCLUSION: We propose a novel MRI grading system for assessing severity of osseous contusions and predicting RTP. Clinically, there was no statistically significant difference in RTP between severe osseous contusions and nondisplaced fractures in elite hockey players.

Presence of subchondral fracture in cases diagnosed as transient osteoporosis of the hip: a retrospective independent reader-based study.

OBJECTIVE: Transient osteoporosis of the hip (TOH) is an uncommon, typically self-limited diagnosis of uncertain etiology. We hypothesize that TOH represents an underlying subchondral fracture, and a discrete fracture line can often be detected on high-resolution MRI. MATERIALS AND METHODS: A retrospective PACS query identified patients meeting imaging criteria for TOH with intense bone marrow edema (BME) in the femoral head on MRI. Those with poor quality studies, other underlying pathologies, or antecedent trauma were excluded. Three musculoskeletal radiologists independently reviewed each case for presence of a definite subchondral fracture line on small field of view (FOV) MR images of the affected hip. Extent of BME, reciprocal acetabular BME, and joint effusion size were also recorded. Binomial logistic regression was performed to determine statistically significant predictors of subchondral fracture. RESULTS: Fifty patients met inclusion criteria (29 females, 0 pregnant). Mean age was 62±12 years (range 35-84). Average duration of symptoms before MRI was 102±135 days. Ten patients had bone densitometry within 2 years of MRI, six demonstrating osteopenia or osteoporosis. Subchondral fractures were unanimously identified in 44/50 (88%). Interclass correlation coefficient with absolute agreement was 0.73, 95% CI (0.57-0.84), indicating near-excellent agreement. Most cases demonstrated a large joint effusion (23/50, 46%) and acetabular BME (31/50, 62%). Increasing size of joint effusion was a statistically significant predictor of subchondral fracture (p=0.05), with 6.9 higher odds. There was a strong correlation with osteopenia/osteoporosis and fracture (p<0.001). CONCLUSION: Discrete subchondral fractures were identified unanimously on small FOV imaging in the majority of TOH cases.

Edema-like marrow signal intensity (ELMSI) associated with nonossifying fibroma (NOF) on MRI: an uncommon finding in a common bone lesion.

OBJECTIVE: To investigate the association between nonossifying fibroma (NOF) and perilesional edema-like marrow signal intensity (ELMSI) on MRI and discuss the clinical and diagnostic implications of this finding. MATERIALS AND METHODS: A retrospective search for "nonossifying fibroma" and "NOF" on knee MRI reports of patients up to 20 years of age over a 5-year period was performed. A total of 77 patients (34 males, 43 females, ages 11-20) were identified, and each MRI was reviewed to evaluate for ELMSI associated with the NOF. Statistical analysis was performed to determine if there was a correlation with the presence of perilesional ELMSI and age, gender, lesion size, or signal characteristics. RESULTS: Twelve patients out of 77 (16%) had ELMSI associated with a NOF. Excluding patients who had additional findings of pathologic fracture (n = 2), a known potential complication of NOFs, and edema related to an adjacent osteoid osteoma (n = 1), a total of 9 patients (12%) had otherwise unexplained perilesional ELMSI. There was no statistically significant difference between patients with vs. without perilesional ELMSI with respect to age (p = 0.08), gender (p = 0.28), lesion size (p = 0.52), or appearance on fluid-sensitive sequences (p = 0.81). CONCLUSION: ELMSI can be seen about NOFs encountered around the knee joint on MRI, which may represent active healing and/or involutional change of this "do not touch" lesion in cases where no other explanation is identified.

Painful type II os naviculare: introduction of a standardized, reproducible classification system.

OBJECTIVE: To provide a novel MRI classification system for the symptomatic type II os naviculare by creating a standardized grading of associated bone marrow edema (BME) and correlating with patient symptoms. METHODS: BME was classified on an ordinal scale: grade 1, faint signal immediately adjacent to the synchondrosis; grade 2, intermediate signal within the os and navicular tuberosity without extending to the navicular body; grade 3, intense signal extending to the navicular body. BME on 59 MRIs was independently graded by three radiologists. Inter- and intra-observer agreement was analyzed using intraclass correlation coefficient. Univariate and multivariate analyses assessed for patient and imaging characteristics predictive of subjective pain score. A cohort of 82 patients without BME represented a control group. RESULTS: Inter-observer agreement of BME grade was 0.95 (CI 0.93-0.97) and intra-observer was 0.92 (CI 0.87-0.96), indicating excellent agreement. In patients with BME, predictors of more severe pain were longer duration of pain (p = 0.02) and presence of soft tissue edema overlying the os naviculare (p < 0.001). One hundred percent of subjects with BME localized their pain to the medial midfoot (59/59) versus 25.6% (21/82) of controls (p < 0.001). CONCLUSIONS: This novel grading system provides reliable quantification of BME associated with os naviculare, which is a specific cause of medial foot/ankle pain. Early diagnosis is important as pain severity worsens with longer duration of symptoms. Pain severity is correlated with soft tissue edema overlying the os, which may be secondary to extrinsic compression, reactive to biomechanical stress, or reflect direct trauma.

Extensive multifocal emphysematous osteomyelitis: fatal outcome in a patient with psychiatric history.

Emphysematous osteomyelitis is a rare entity with potentially devastating consequences, even after prompt and aggressive intervention. It is characterized by intraosseous gas and may be complicated by adjacent abscess formation. There are a handful of previously reported cases of emphysematous osteomyelitis, but none to the degree as reported here. Specifically, we report an extremely rare case of extensive multifocal emphysematous osteomyelitis involving both the axial and appendicular skeleton in a 20-year-old woman.

Predicting osteomyelitis in patients whose initial MRI demonstrated bone marrow edema without corresponding T1 signal marrow replacement.

PURPOSE: We endeavored to determine which characteristics of diabetic ulcers portend the strongest risk for osteomyelitis in patients whose initial T1-weighted imaging was normal. By determining which features have a greater risk for osteomyelitis, clinicians can treat patients more aggressively to reduce the sequela of inadequately treated osteomyelitis. MATERIALS AND METHODS: We performed a retrospective analysis of MR imaging from 60 pedal ulcers with suspected osteomyelitis. Ulcer dimensions and depth were measured. Ratios of marrow ROI/joint fluid ROI on T2/STIR sequences were obtained. Progression to osteomyelitis on subsequent MRI was characterized by loss of normal marrow signal on T1-weighted images. Statistical analysis was performed with a two-sample t test and Cox proportional hazard model. A p value < 0.05 was used as the threshold for statistical significance. RESULTS: Sixty MR exams were identified. Thirty-four progressed to osteomyelitis. Marrow ROI/joint fluid ratios averaged 65% in the osteomyelitis group, and 45% in the non-osteomyelitis group, p < 0.001. ROI ratios > 53% had a 6.5-fold increased risk of osteomyelitis, p < 0.001. Proximity to bone averaged 6 mm in the osteomyelitis group and 9 mm in the non-osteomyelitis group, p = 0.02. Ulcer size averaged 4 cm2 in the osteomyelitis group versus 2.4 cm2 in the non-osteomyelitis group, p = 0.07. Ulcers greater than 3 cm2 has a 2-fold increase in the risk of osteomyelitis, p = 0.04. CONCLUSION: Increasing bone marrow ROI signal/joint fluid ratios on T2/STIR images were the strongest risk factors for developing osteomyelitis, while ulcer size and depth are weaker predictors.

Efficacy of image-guided synovial biopsy.

OBJECTIVE: A variety of benign and neoplastic lesions can affect the synovium, including pigmented villonodular synovitis (PVNS) and synovial chondromatosis. Prior to surgical resection, accurate characterization of synovial lesions is necessary for appropriate treatment planning. Additionally, recent advances in potential medical therapies for PVNS could decrease or eliminate the need for surgery in some cases. Such treatment options demand accurate characterization of synovial lesions prior to treatment. METHODS AND MATERIALS: Institutional IRB approval was obtained. We identified 54 synovial biopsies performed at our institution using a comprehensive database search under ultrasound (US) or computed tomography (CT) guidance. Cases were reviewed for pre-procedure imaging, location, biopsy approach, biopsy results, post-procedure complications, and surgical pathology if synovectomy was performed. RESULT: A total of 54 image-guided synovial biopsies were performed, 36 using CT guidance and 18 using US guidance. Six different anatomic locations were biopsied (the hip, knee, shoulder, elbow, ankle, and temporomandibular joint). Synovial tissue was obtained in 89% of cases (48/54). CT-guided biopsies had a positive yield of 86% (31/36) and US-guided biopsies had a positive yield of 94% (17/18). Surgical pathology was obtained in 30 of the cases and image-guided biopsy concordance was 90% (27/30). Of the patients taken for synovectomy, biopsy concordance of suspected neoplastic lesions was 100% (23/23). In cases of suspected neoplasm, the concordance between image-guided biopsy and surgical pathology was 96% (22/23). There were no reported complications. CONCLUSION: Image-guided biopsy of synovial lesions is safe and effective for establishing a definitive diagnosis prior to surgical or other intervention.

Talus Partitus: a review of five cases diagnosed by MRI.

Talus partitus is a rare skeletal developmental abnormality characterized by a split of the posterior talar bone in the coronal plane. Patients with talus partitus typically present with posterior ankle pain and instability, often displaying varying degrees of chondrosis and secondary degenerative change on imaging. To date, only few case reports describing the imaging appearance of talus partitus have been published. The majority of these publications are limited to radiographic and computed tomography (CT) imaging findings, despite the ubiquity of magnetic resonance imaging (MRI). To the authors' knowledge, there is little description of typical MRI findings of the symptomatic talus partitus in the radiologic literature. We present a series of five cases of talus partitus identified on MRI and examine pitfalls in diagnosis, differential considerations, pathophysiology, and treatment options.

Sports Injuries about the Hip: What the Radiologist Should Know.

Injuries of the hip and surrounding structures represent a complex and commonly encountered scenario in athletes, with improper diagnosis serving as a cause of delayed return to play or progression to a more serious injury. As such, radiologists play an essential role in guiding management of athletic injuries. Familiarity with hip anatomy and the advantages and limitations of various imaging modalities is of paramount importance for accurate and timely diagnosis. Magnetic resonance (MR) imaging is often the modality of choice for evaluating many of the injuries discussed, although preliminary evaluation with conventional radiography and use of other imaging modalities such as ultrasonography (US), computed tomography, and bone scintigraphy may be supplementary or preferred in certain situations. Stress fractures, thigh splints, and posterior hip dislocations are important structural injuries to consider in the athlete, initially imaged with radiographs and often best diagnosed with MR imaging. Apophyseal injuries are particularly important to consider in young athletes and may be acute or related to chronic repetitive microtrauma. Femoroacetabular impingement has been implicated in development of labral tears and cartilage abnormalities. Tear of the ligamentum teres is now recognized as a potential cause of hip pain and instability, best evaluated with MR arthrography. Greater trochanteric pain syndrome encompasses a group of conditions leading to lateral hip pain, with US playing an increasingly important role for both evaluation and image-guided treatment. Muscle injuries and athletic pubalgia are common in athletes. Lastly, snapping hip syndrome and Morel-Lavallée lesions are two less common but nonetheless important considerations. ©RSNA, 2016.

Core Injuries Remote from the Pubic Symphysis.

The core, or central musculoskeletal system of the torso, is essential for participating in sports and other physical activities. Core injuries are commonly encountered in athletes and active individuals. The importance of the midline pubic plate and rectus abdominis-adductor aponeurosis for core stability and function is discussed in the literature. This review article examines other important core injuries remote from the pubic symphysis, relevant clinical features, and preferred approaches to imaging. Several specific syndromes encountered in the core are reviewed. By protocoling imaging studies and identifying pathology, radiologists can add value to the clinical decision-making process and help guide therapeutic options.