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Objective To determine the imaging characteristics and stability over time of sternal lesions identified on breast MRI in patients without history of cancer. Methods An IRB-approved retrospective analysis of all breast MRIs performed at our institution from September 1, 2017 to December 1, 2021 that included one of several key words related to the sternum. Studies with history of non-dermatologic malignancy including breast cancer, absence of a true sternal lesion, or presence of symptoms during the examination were excluded. Imaging was reviewed for size, distribution, signal characteristics, and presence of contrast enhancement, perilesional edema, periosteal edema, or intralesional fat. Available comparison imaging, clinical history, and follow-up recommendations were reviewed. Descriptive statistics were used to summarize lesion data. Results Of 60 lesions included from 60 patients, 40 lesions with more than two years of comparison imaging were either stable or decreased in size and none demonstrated change in signal characteristics. The majority of these presumed benign lesions demonstrated hypointense signal on T1-weighted sequences (21/40, 52.5%), hyperintense signal on fluid-sensitive sequences (33/40, 82.5%), contrast enhancement (32/40, 80.0%), and absence of clear intralesional fat (29/40, 72.5%). One patient who did not have comparison imaging was diagnosed with malignancy (multiple myeloma) eight months following their MRI. This lesion demonstrated uniquely diffuse and heterogeneous enhancement but did not undergo biopsy. Conclusion Sternal lesions in women without history of non-dermatologic malignancy have a very low likelihood of malignancy. Common imaging characteristics of the presumed benign lesions can inform imaging recommendations when incidental sternal lesions are discovered.

Inflammatory back pain is a hallmark feature of axial spondyloarthritis, a heterogeneous group of inflammatory disorders which affects the sacroiliac joints and spine. Imaging plays a key role in diagnosis of this disease and in facilitating appropriate treatment. This document provides evidence-based recommendations on the appropriate use of imaging studies during multiple stages of the clinical evaluation of patients with suspected or known axial spondyloarthritis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Compare radiation dose of lumbar spine epidural steroid injections (ESIs) performed under fluoroscopy guidance and ultralow-dose CT-fluoroscopy guidance. Retrospective review of consecutive lumbar ESIs performed using fluoroscopy, between May 2017 and April 2019, and using ultralow-dose CT-fluoroscopy, between August 2019 and February 2021, was performed. Ultralow-dose CT-fluoroscopy technique omits a planning CT scan, utilizes CT-fluoroscopy, and minimizes radiation dose parameters. Patient characteristics (age, sex, height, weight, body mass index (BMI)), procedural characteristics (anatomic level, type of ESI, procedure time, pain reduction, complications, trainee participation), and radiation dose were compared. Chi-square tests and two-sample t-tests were performed for statistical analysis. One hundred and forty-seven patients (mean age 55.8 ± 16.7; 85 women) underwent ESIs using fluoroscopy. Sixty-six patients (mean age 60.9 ± 16.7; 33 women) underwent ESIs using ultralow-dose CT-fluoroscopy. The effective dose for the fluoroscopy group was 0.30 mSv ± 0.34, compared to 0.15 mSV ± 0.11 for ultralow-dose CT-fluoroscopy (p

To 1) Determine whether virtual reading room (VRR) engagement endured after initial inception amidst the COVID-19 pandemic, 2) Understand factors affecting VRR utilization by radiologists and consulting providers.This Institutional Review Board-exempt study was performed at a large academic medical center. In response to pandemic-induced social-distancing requirements, divisional VRRs replicated the ability for provider "drop-in" consultation including speaking with a radiologist while viewing images together. Average daily users were compared between 7/1/2020-9/28/2020 (more stringent social-distancing guidelines) vs. 11/8/2021-2/5/2022 (more relaxed guidelines), using chi-squared tests. Focus group data on utilization within year one of inception was gathered from radiologists and consulting providers (Internal Medicine, Surgery, and Emergency Medicine), and responses used to predict probability of continued utilization post-social distancing. Linear regression compared 2022 total active user replies from inception through 1/31/22 with 2021 predictive divisional utilization data.There were no significant differences in average daily users during the 2020 period (73) vs. the 2022 period (65; p=0.09). 2022 VRR utilization was higher in radiology divisions with standardized workflows (relying more on cross-sectional imaging) than those with interrupted workflows (relying more on real-time imaging such as ultrasound), RVRR engagement endured two years post-inception despite reduced social-distancing guidelines, indicating VRRs may serve as a lasting part of healthcare architecture. Reading room workflow and consulting provider question type predict VRR utilization at the divisional level.

Objective 1) To describe a simplified multidisciplinary grading system for the most clinically relevant lumbar spine degenerative changes. 2) To measure the inter-reader variability among non-radiologist spine experts in their use of the classification system for interpretation of a consecutive series of lumbar spine magnetic resonance imaging (MRI) examinations. Methods ATS multidisciplinary and collaborative standardized grading of spinal stenosis, foraminal stenosis, lateral recess stenosis, and facet arthropathy was developed. Our institution’s picture archiving and communication system was searched for 50 consecutive patients who underwent non-contrast MRI of the lumbar spine for chronic back pain, radiculopathy, or symptoms of spinal stenosis. Three fellowship-trained spine subspecialists from neurosurgery, orthopedic surgery, and physiatry interpreted the 50 exams using the classification at the L4–L5 and L5–S1 levels. Inter-reader agreement was assessed with Cohen’s kappa coefficient. Results For spinal stenosis, the readers demonstrated substantial agreement (κ = 0.702). For foraminal stenosis and facet arthropathy, the three readers demonstrated moderate agreement (κ = 0.544, and 0.557, respectively). For lateral recess stenosis, there was fair agreement (κ = 0.323). Conclusions A simplified universal grading system of lumbar spine MRI degenerative findings is newly described. Use of this multidisciplinary grading system in the assessment of clinically relevant degenerative changes revealed moderate to substantial agreement among non-radiologist spine physicians. This standardized grading system could serve as a foundation for interdisciplinary communication.

A focused hip MRI (FHMR) for the detection of radiographically occult hip fractures was implemented in our emergency department (ED) in 2013. The goal of this study was to assess the clinical utility of this protocol. We retrospectively reviewed radiology reports of 262 unique patients who underwent 263 FHMR (coronal T1, coronal STIR, axial T2 fat saturated) for suspected hip fracture in the ED from October 2013 to March 2020. Electronic medical records were reviewed for the ED course, follow-up imaging, and clinical management within 90 days. Seventy-one patients had one or more fractures identified by FHMR: one-third had proximal femoral fractures; two-third had pelvic fractures. Of these 71 patients, 53 (74%) had radiographically occult fractures, including 14 (20%) with occult proximal femoral fractures; 4 patients had fractures occult on CT. Nineteen patients with a suspected fracture on radiography were found to have no fracture on FHMR. Four fractures not reported on FHMR were later seen on follow-up imaging: these included 1 isolated greater trochanter, 1 additional ischial tuberosity, 1 additional superior pubic ramus, and 1 additional sacrum. All four fractures were treated non-operatively. Muscle/tendon injury was the most common type of injury, seen in 50% (130/262) patients with the most commonly torn tendons being the hamstring (44%; 15/34) followed by gluteus medius tendon (18%; 6/34). A full-hip or pelvis MRI was done after FHMR in only 5 patients, primarily for the purpose of better characterizing findings already identified on FHMR (2 for fracture, 2 for tendon injury, 1 for soft tissue metastasis). Only one of these five studies provided new information: ruling out a previously questioned fracture. Clinical management of the vast majority of patients was based solely on findings from the FHMR. FHMR offers reliable identification of radiographically occult hip fractures and muscle/tendon injuries. The protocol is well trusted in guiding patient management in our ED.

Objective To systematically review the published literature on genicular artery embolization (GAE) for osteoarthritis (OA) related knee pain. Materials and Methods Using three databases, a systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Outcome measures included the Visual Analog Scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Results Three single-arm studies were included from an initial search yielding 305 results. One hundred and eighty-six knees in 133 patients with either mild-to-moderate (174/186, 94%) or severe (12/186, 6%) OA underwent embolization with either imipenem/cilastatin sodium (159/186, 85%) or embozene (27/186, 15%). Technical success was 100%. Average VAS improved from baseline at 1 day, 1 week, 1 month, 3 months, 4 months, 6 months, 1 year and 2 years (66.5 at baseline vs 33.5, 32.7, 33.8, 28.9, 29.0, 22.3, 14.8 and 14.0, respectively). Average WOMAC scores improved from baseline at 1, 3, 4, 6, 12 and 24 months (45.7 at baseline vs 24.0, 31.0, 14.8, 14.6, 8.2 and 6.2). Severe OA in 12 cases showed initially improved VAS, but was not sustained. Minor adverse events such as erythema in the region of embolization (21/186, 11%), puncture-site hematoma (18/186, 10%), paresthesia (2/186, 1%) and fever (1/186, 0.5%) were reported. Conclusion Limited single-arm studies report GAE is promising for treating OA-related pain. Most treatments performed for mild-to-moderate OA demonstrated durable clinical responses from 6 months to 4 years. Limited data for severe OA suggest a non-durable response. Future studies should be standardized to facilitate comparison and control for placebo effect.

Meniscal allograft transplantation is an emerging surgical option for younger patients with symptomatic meniscal deficiency, which aims to restore anatomic biomechanics and load distribution in the knee joint, and by so doing to potentially delay accelerated osteoarthritis. In this review article, we summarize the structure and biomechanics of the native meniscus, describe indications and procedure technique for meniscal allograft transplantation, and demonstrate the spectrum of expected postoperative imaging and role of imaging to identify potential complications.

While weight-bearing radiographs are considered the optimal method for evaluation of joint spaces in osteoarthritis, non-weight-bearing radiographs are often performed. The purpose of this study is to evaluate the rate of follow-up radiographs in patients receiving non-weight-bearing radiographs for chronic knee pain in the outpatient setting, compared with patients receiving weight-bearing radiographs. Consecutive patients who received non-weight-bearing knee radiographs for chronic knee pain between January 1, 2018, and June 15, 2019, were included. Exclusion criteria included trauma, concern for infection or tumor, and post-surgical radiographs. An age- and sex-matched control group of 100 patients who received weight-bearing knee radiographs was compiled. The proportion of follow-up radiographs within 1 year was compared between the study and control groups with chi-squared tests. Four hundred non-weight-bearing knee radiographic examinations were included. There were 74/400 (18.5%) follow-up radiographs within 12 months. All follow-up radiographs were weight-bearing. In the control group, 4/100 (4%) had follow-up weight-bearing radiographs within 1 year (p

Background and Purpose The purpose of this study is to assess the differences in degenerative spine MRI reporting between subspecialty-trained attending neuroradiologists and musculoskeletal radiologists (MSK) at a single institution, academic medical center. Materials and Methods Fifty consecutive outpatient noncontrast lumbar spine examinations were selected from the Picture Archiving and Communication System. Three MSK and 3 neuroradiologists (NR) independently reviewed and interpreted the exams at the L4-L5 and L5-S1 levels in the same manner as in clinical practice. The assessment of neural foraminal stenosis (NFS) and spinal canal stenosis (SCS) was converted to a 5-point ordinal scale. The assessment of lateral recess stenosis (LRS) and facet osteoarthritis (FO) was recorded as present/absent. Intersubspecialty and intrasubspecialty analysis was performed using Cohen's kappa coefficient with a binary matrix of all reader pairs. Results There was moderate intersubspecialty agreement (k = 0.527) for NFS and SCS (k = 0.540). Intersubspecialty agreement was slight for LRS (k = 0.0818) and FO (k = 0.176). The MSK group demonstrated greater intrasubspecialty agreement in assessment of NFS and SCS compared to the NR group, with nonoverlapping confidence intervals. The NR group demonstrated greater nominal intrasubspecialty agreement in the assessment of both LRS and FO, although with nonoverlapping confidence intervals. Conclusion There is moderate intersubspecialty agreement between MSK radiologists and neuroradiologists in reporting the severity of NFS and SCS, although MSK radiologists demonstrated greater intrasubspecialty agreement. There is slight intersubspecialty agreement for LRS and FO. The demonstration of differences in inter-reader agreement is a crucial first step to attempt to ameliorate these variabilities.

Temporomandibular disorders encompass multiple pathologies of the temporomandibular joint that manifest as middle/inner ear symptoms, headache, and/or localized TMJ symptoms. There is an important although somewhat limited role of imaging in the diagnostic evaluation of temporomandibular disorders. In this manuscript, we provide a comprehensive review of TMJ anatomy, outline potentially important features of TMJ disc ultrastructure and biochemistry in comparison with the intervertebral disc and knee meniscus, and provide imaging examples of the TMJ abnormalities currently evaluable with MRI and CT. In addition, we provide an overview of emerging and investigational TMJ imaging techniques in order to encourage further imaging research based on the biomechanical alterations of the TMJ disc.

Prompt identification of traumatic pelvic fractures in the elderly is critical to guide clinical management; however, the accuracy of pelvic radiographs is often compromised by multiple factors. The purpose of this study is to examine the diagnostic accuracy of radiographs for the detection of pelvic fractures, with CT as the standard of reference.A retrospective review was performed of patients ≥ 65 years with traumatic pelvic fractures evaluated with both pelvic radiography and computed tomography (CT) from May 2016 to October 2019. Pelvic fractures were classified into fractures of the pubis, ilium, ischium, sacrum, and acetabulum. All pelvic radiographs were independently reviewed by two emergency radiologists. Original CT reports were utilized for the reference standard.177 patients were included, with a total of 555 fractures. The mean age was 81 years and 68% were female. The most common mechanism of injury was fall (62%), followed by motor vehicle accidents (18%). The most fractured bone was the pubis (314/555 fractures). Global pooled sensitivity for pelvic radiographs in detecting pelvic fractures compared to CT was 48%, with a specificity of 93%. Sensitivity for the detection of pelvic fractures is classified by the following types: pubis 61%, acetabulum 60%, ilium 41%, sacrum 20%, and ischium 17%. Eighteen patients (10%) required surgical fixation. Mortality was 8%.Pelvic radiographs have low sensitivity in detecting traumatic pelvic fractures. These radiographically occult fractures may be clinically significant as a cause of long-term pain and may require orthopedic consultation and possible surgical management.

OBJECTIVE. The purpose of this study was to assess the diagnostic performance of CT for detection of occult proximal femoral fracture. MATERIALS AND METHODS. A systematic search adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed for studies of the sensitivity and specificity of CT for detection of hip fracture. Two independent investigators extracted data and assessed the quality of each study using the revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). A qualitative systematic review and quantitative meta-analysis were performed. A Bayesian bivariate random effects meta-analysis model with integrated nested Laplace approximation was used to estimate sensitivity and specificity. RESULTS. Thirteen heterogeneously reported studies were assessed that included 1248 patients (496 with a hip fracture and 752 without) with MRI or clinical follow-up as the reference standard. There were 50 false-negative examinations. The summary estimate of sensitivity was 94% and of specificity was 100%. CONCLUSION. CT can be considered a reasonable choice when occult proximal femoral fracture is suspected clinically in patients for whom MRI is contraindicated or not readily available. However, for patients with ongoing clinical concern about hip fracture despite normal CT findings, MRI should be performed.

The purpose of this study was to demonstrate the ability of a custom window blending algorithm to depict multicompartmental disease processes of the maxillofacial region in a single image, using routine computed tomography (CT) DICOM data. Five cases were selected from case files demonstrating trauma, infection, and malignancy of the maxillofacial region on routine CT examinations. Images were processed with a modified Relative Attenuation-Dependent Image Overlay (RADIO) window-blending algorithm in Adobe Photoshop controlled by ExtendScript. The modified RADIO algorithm was able to demonstrate pertinent multicompartmental imaging findings in each of the examinations, allowing simultaneous visualization of clinically relevant bone and soft tissue findings in a single image, without needing to change window and level settings. A custom window blending algorithm can demonstrate a range of multicompartmental pathology in the maxillofacial region in a single image.

To compare the diagnostic performance and inter-reader agreement of an abbreviated (5 min) MR protocol compared to a complete (25 min) protocol, for evaluation of suspected tibial bone stress injury. This IRB-approved retrospective study consisted of 95 consecutive MR examinations in 88 patients with suspected tibial bone stress injury. Three musculoskeletal radiologists independently classified all examinations utilizing both an abbreviated protocol consisting only of axial T2-weighted images with fat suppression, and after a washout period again classified the complete examinations. Accuracy was calculated as proportion of cases classified exactly, within 1 grade, within 2 grades, and also utilizing a simplified “clinically relevant” classification combining grades 2, 3, and 4A into a single group. Significance testing was performed with the chi-test, and a post-hoc power analysis was performed. Inter-reader agreement was calculated with Kendall’s coefficient of concordance, with significance testing performed utilizing the z-test after bootstrapping to obtain the standard error. There was no significant difference in accuracy of grading tibial bone stress injuries between complete and abbreviated examinations. For complete exams, pooled exact accuracy was 47.8%; accuracy within 1 grade was 82.8%; and accuracy within 2 grades was 96.1%. For the abbreviated protocol, corresponding accuracies were 50.2, 82.0, and 93.9%. With the “clinically relevant” simplified classification, accuracy was 58.6% for complete exams and 64.2% for abbreviated exams. There was no significant difference in inter-reader agreement, with substantial agreement demonstrated for both complete (Kendall coefficient of concordance 0.805) and abbreviated examinations (coefficient of 0.767).

The purpose of this study is first to determine the clinical utility of the postprocedure scan in detecting postinterventional complications after CT-guided musculoskeletal biopsies, and second to evaluate the contribution to the radiation dose of the postprocedural CT scan. Retrospective analysis of 500 consecutive CT-guided musculoskeletal biopsies over an 18-month period from 29 March 2017 to 28 September 2018, where spiral postprocedure scans were obtained in every case. To assess the clinical utility of postinterventional CT scans, it was determined whether immediate post-procedural complications were detected on the postprocedural scans only or were also seen on the procedural images. To evaluate the relative radiation exposure of postprocedural scans, a ratio was obtained of the dose–length product (DLP) of the postprocedural scan compared with the total DLP of each case. A total of 397 bone biopsies and 103 soft-tissue biopsies were performed in 471 patients. The immediate postprocedural complication rate was 0.4% (2 out of 500) in all procedures. Both complications were minor (small hematomas) and detected only on postinterventional CT scans. The average total DLP for the procedures was 383.5 mGy*cm. The average DLP of the postprocedural scan was 64.0 mGy*cm. The average radiation dose contribution of the postprocedural CT scans toward the total DLP was 17.4%. Immediate postprocedural complications in CT-guided musculoskeletal interventions are rare. When complications do occur, they are usually minor. To substantially reduce radiation dose, postinterventional CT scans should not be performed routinely.

Objective.Pannus formation in the atlanto-axial joint is a well-recognized complication of rheumatoid arthritis (RA). Occasionally, atlanto-axial pannus is reported when patients without a history of RA undergo magnetic resonance imaging (MRI) of the cervical spine. We sought to further characterize these patients.Methods.The Partners HealthCare Research Patient Data Registry was free-text searched for “atlanto-axial” AND “pannus” in cervical spine MRI reports from 2001 to 2015. Cases with MRI reports describing pannus were reviewed. Clinical data were extracted by chart review in cases with confirmed atlanto-axial pannus (n = 105).Results.Twenty-nine patients (27.6%) had RA, all of whom except one carried this diagnosis at the time of the MRI scan. Only 1 of 77 patients without a history of RA was subsequently diagnosed with RA (1.3%, 95% CI 0.1–7.0%, median followup 3.6 yrs). Non-RA patients were significantly older (median age 79 vs 63 yrs, p < 0.0001), less frequently female (55% vs 86%, p = 0.0032), and more likely to have undergone prior cervical spine surgery (18% vs 0%, p = 0.016) compared with RA patients. Thirty-four non-RA patients (44.7%) either had a clinical diagnosis of calcium pyrophosphate dihydrate disease (CPPD) or imaging evidence for tissue calcification. There were no significant differences in age or sex between the CPPD subgroup and other non-RA patients. Twenty-eight patients (26.7%) underwent cervical spine surgery.Conclusion.Patients without RA diagnosis and incidental atlanto-axial pannus on cervical spine MRI are unlikely to have previously unrecognized RA. Degenerative disease and tissue calcification may contribute to pannus formation in these patients.

Compare radiation dose of lumbar spine epidural steroid injections (ESIs) performed under fluoroscopy guidance and ultralow-dose CT-fluoroscopy guidance.Retrospective review of consecutive lumbar ESIs performed using fluoroscopy, between May 2017 and April 2019, and using ultralow-dose CT-fluoroscopy, between August 2019 and February 2021, was performed. Ultralow-dose CT-fluoroscopy technique omits a planning CT scan, utilizes CT-fluoroscopy, and minimizes radiation dose parameters. Patient characteristics (age, sex, height, weight, body mass index (BMI)), procedural characteristics (anatomic level, type of ESI, procedure time, pain reduction, complications, trainee participation), and radiation dose were compared. Chi-square tests and two-sample t-tests were performed for statistical analysis.One hundred and forty-seven patients (mean age 55.8 ± 16.7; 85 women) underwent ESIs using fluoroscopy. Sixty-six patients (mean age 60.9 ± 16.7; 33 women) underwent ESIs using ultralow-dose CT-fluoroscopy. The effective dose for the fluoroscopy group was 0.30 mSv ± 0.34, compared to 0.15 mSV ± 0.11 for ultralow-dose CT-fluoroscopy (p 0.001). The average age in the CT-fluoroscopy group was older (p = 0.04), and there was more trainee participation in the fluoroscopy group (p 0.001); otherwise there was no statistically significant difference in patient or procedural characteristics between the conventional fluoroscopy group and the ultralow-dose CT-fluoroscopy group. There was no statistically significant difference in immediate post-procedure pain reduction between the groups (p = 0.16). Four intrathecal injections occurred only in the fluoroscopy group, though this difference was not significant (p = 0.18).Ultralow-dose CT-fluoroscopy technique for image-guided lumbar spine ESIs can lower radiation dose compared to fluoroscopy-guided technique.

Background and Purpose To determine the efficacy of standardized definitions of degenerative change in reducing variability in interpretation of lumbar spine magnetic resonance imaging within and between groups of subspecialty-trained neuroradiologists (NR) and musculoskeletal radiologists (MSK). Materials and Methods Six radiologists, three from both NR and MSK groups were trained on a standardized classification system of degenerative change. After an 11-month washout period, they independently re-interpreted fifty exams at the L4-L5 and L5-S1 levels. Responses were converted to a six-point ordinal scale for the assessment of neural foraminal stenosis and spinal canal stenosis (SCS), three-point scale for lateral recess stenosis, and four-point scale for facet osteoarthritis (FO). Intra-subspecialty and inter-subspecialty analysis was performed using the weighted Cohen's kappa with a binary matrix of all reader pairs. Results Inter-subspecialty agreement improved from k=0.527 (moderate) to k=0.602 (substantial) for neural foraminal stenosis, from k=0.540 (moderate) to k=0.652 (substantial) for SCS, from k=0.0818 (slight) to k=0.337 (fair) for lateral recess stenosis, and from k=0.176 (slight) to k=0.495 (moderate) for FO. The NR group demonstrated improved intra-subspecialty agreement for the assessment of SCS, from k=0.368 (fair) to k=0.638 (substantial). The MSK group demonstrated improved intra-subspecialty agreement for the assessment of FO, from k=0.134 (slight) to k=0.413 (moderate). Intra-subspecialty agreement was similar for other parameters before and after training. Conclusions As result of the standardized definitions training, the NR and MSK groups each improved in one of the four parameters, while inter-subspecialty variability improved in all four parameters. These definitions may be useful in clinical practice across radiology subspecialties.

Objective To systematically review the published literature on genicular artery embolization (GAE) for osteoarthritis (OA) related knee pain. Materials and Methods Using three databases, a systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Outcome measures included the Visual Analog Scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Results Three single-arm studies were included from an initial search yielding 305 results. One hundred and eighty-six knees in 133 patients with either mild-to-moderate (174/186, 94%) or severe (12/186, 6%) OA underwent embolization with either imipenem/cilastatin sodium (159/186, 85%) or embozene (27/186, 15%). Technical success was 100%. Average VAS improved from baseline at 1 day, 1 week, 1 month, 3 months, 4 months, 6 months, 1 year and 2 years (66.5 at baseline vs 33.5, 32.7, 33.8, 28.9, 29.0, 22.3, 14.8 and 14.0, respectively). Average WOMAC scores improved from baseline at 1, 3, 4, 6, 12 and 24 months (45.7 at baseline vs 24.0, 31.0, 14.8, 14.6, 8.2 and 6.2). Severe OA in 12 cases showed initially improved VAS, but was not sustained. Minor adverse events such as erythema in the region of embolization (21/186, 11%), puncture-site hematoma (18/186, 10%), paresthesia (2/186, 1%) and fever (1/186, 0.5%) were reported. Conclusion Limited single-arm studies report GAE is promising for treating OA-related pain. Most treatments performed for mild-to-moderate OA demonstrated durable clinical responses from 6 months to 4 years. Limited data for severe OA suggest a non-durable response. Future studies should be standardized to facilitate comparison and control for placebo effect.

Dual-energy CT is increasingly being used in the emergency department to help diagnose acute conditions. Its applications include demonstrating bone marrow edema (BME) seen in the setting of occult fractures and other acute conditions. Dual-energy CT acquires data with two different x-ray energy spectra and is able to help differentiate materials on the basis of their differential energy-dependent x-ray absorption behaviors. Virtual noncalcium (VNCa) techniques can be used to suppress the high attenuation of trabecular bone, thus enabling visualization of subtle changes in the underlying attenuation of the bone marrow. Visualization of BME can be used to identify occult or mildly displaced fractures, pathologic fractures, metastases, and some less commonly visualized conditions such as ligamentous injuries or inflammatory arthritis. The authors' major focus is use of dual-energy CT as a diagnostic modality in the setting of trauma and to depict subtle or occult fractures. The authors also provide some scenarios in which dual-energy CT is used to help diagnose other acute conditions. The causes and pathophysiology of BME are reviewed. Dual-energy CT image acquisition and VNCa postprocessing techniques are also discussed, along with their applications in emergency settings. The authors present potential pitfalls and limitations of these techniques and their possible solutions.©RSNA, 2020.

While weight-bearing radiographs are considered the optimal method for evaluation of joint spaces in osteoarthritis, non-weight-bearing radiographs are often performed. The purpose of this study is to evaluate the rate of follow-up radiographs in patients receiving non-weight-bearing radiographs for chronic knee pain in the outpatient setting, compared with patients receiving weight-bearing radiographs.Consecutive patients who received non-weight-bearing knee radiographs for chronic knee pain between January 1, 2018, and June 15, 2019, were included. Exclusion criteria included trauma, concern for infection or tumor, and post-surgical radiographs. An age- and sex-matched control group of 100 patients who received weight-bearing knee radiographs was compiled. The proportion of follow-up radiographs within 1 year was compared between the study and control groups with chi-squared tests.Four hundred non-weight-bearing knee radiographic examinations were included. There were 74/400 (18.5%) follow-up radiographs within 12 months. All follow-up radiographs were weight-bearing. In the control group, 4/100 (4%) had follow-up weight-bearing radiographs within 1 year (p 0.001).Outpatients who underwent non-weight-bearing knee radiographs for chronic pain had a higher frequency of repeat imaging than those who initially underwent weight-bearing knee radiographs. These results suggest that non-weight-bearing knee radiographs are of lower clinical utility compared with weight-bearing radiographs.

To demonstrate the effect of teaching a simplified treatment-based classification of proximal femoral fractures on the accuracy, confidence, and inter-reader agreement of radiology residents. The authors hypothesize that these measures will improve after viewing an educational presentation. Three radiology residents independently classified 100 operative proximal femoral fractures, both before and after viewing a 45-min educational video describing the simplified classification scheme, with a washout period of at least 12 weeks between sessions. Based on the gold standard established by consensus of two radiologists and an orthopedic trauma surgeon utilizing intraoperative fluoroscopic imaging, operative reports, and pre-procedural imaging, accuracy of classification was calculated for each reader before and after viewing the educational video. Reader confidence was recorded on a 0–10 scale, and inter-reader agreement was calculated with Fleiss’s kappa. McNemar’s test was used to compare accuracy, a paired t test was used to compare confidence, and the Z-test was used to compare kappa values after bootstrapping to determine the standard error of the mean. The study cohort included 60/100 females, with a mean age of 76.6 years. The pooled classification accuracy was initially 65%, which improved to 80% in the second reading session after viewing the educational video (p

Traumatic and atraumatic fractures are entities with distinct but often overlapping clinical manifestations, imaging findings, and management protocols. This article is a review of terminology, etiology, and key imaging features that affect management of atraumatic fractures including stress fractures, atypical femoral fractures, and pathologic fractures. The terminology of atraumatic fractures is reviewed, with an emphasis on the distinctions and similarities of stress, atypical, and pathologic fractures. The basic biomechanics of normal bone is described, with an emphasis on the bone remodeling pathway. This framework is used to better convey the shared etiologies, key differences, and important imaging findings of these types of fractures. Next, the characteristic imaging findings of this diverse family of fractures is discussed. For each type of fracture, the most clinically relevant imaging features that guide management by the multidisciplinary treatment team, including orthopedic surgeons, are reviewed. In addition, imaging features are reviewed to help discriminate stress fractures from pathologic fractures in patients with challenging cases. Finally, imaging criteria to risk stratify an impending pathologic fracture at the site of an osseous neoplasm are discussed. Special attention is paid to fractures occurring in the proximal femur because the osseous macrostructure and mix of trabecular and cortical bone of the proximal femur can function as a convenient framework to understanding atraumatic fractures throughout the skeleton. Atraumatic fractures elsewhere in the body also are used to illustrate key imaging features and treatment concepts. ©RSNA, 2018.

Rationale and Objectives This study aims to demonstrate the feasibility of processing computed tomography (CT) images with a custom window blending algorithm that combines soft-tissue, bone, and lung window settings into a single image; to compare the time for interpretation of chest CT for thoracic trauma with window blending and conventional window settings; and to assess diagnostic performance of both techniques. Materials and Methods Adobe Photoshop was scripted to process axial DICOM images from retrospective contrast-enhanced chest CTs performed for trauma with a window-blending algorithm. Two emergency radiologists independently interpreted the axial images from 103 chest CTs with both blended and conventional windows. Interpretation time and diagnostic performance were compared with Wilcoxon signed-rank test and McNemar test, respectively. Agreement with Nexus CT Chest injury severity was assessed with the weighted kappa statistic. Results A total of 13,295 images were processed without error. Interpretation was faster with window blending, resulting in a 20.3% time saving (P Conclusions In this pilot study utilizing retrospective data, window blending allows faster preliminary interpretation of axial chest CT performed for trauma, with no significant difference in diagnostic performance compared to conventional window settings. Future studies would be required to assess the utility of window blending in clinical practice.

To explore clinical applications of a novel conventional computed tomography (CT) color post-processing algorithm to increase conspicuity of nondisplaced trabecular fractures. The algorithm was created in Adobe Photoshop and Adobe Extendscript, utilizing DICOM images from conventional CT as source images. A total of six representative cases were selected and processed. No statistical analyses were performed. A total of six cases are demonstrated, five with MRI correlation demonstrating corresponding fractures and bone marrow edema, including a case of sacral insufficiency fracture, two cases of vertebral body fracture, two cases of nondisplaced hip fracture, and a knee bone marrow edema lesion (without MRI correlate). All cases were processed successfully without error. A conventional CT color post-processing algorithm may be clinically useful in increasing conspicuity of nondisplaced fractures and bone marrow edema. A potential pitfall is the presence of subchondral or marrow sclerosis, which may mimic edema. Future prospective studies will be necessary to evaluate diagnostic performance.

The objective of this study is to assess the clinical utility of internal rotation traction radiography in the classification of proximal femoral fractures.The study cohort included 78 consecutive patients who were surgically treated for a proximal femoral fracture and for whom preoperative physician-assisted internal rotation traction radiographs of the fractured hip were obtained in addition to standard radiographs. Two radiologists who were blinded to clinical information independently classified each fracture without the traction view and then with the traction view. The radiologists also reported their confidence (expressed as a percentage) in their classifications. The reference standard was the consensus interpretation of intraoperative C-arm fluoroscopic images by two orthopedic surgeons and one radiologist. Classification accuracy was compared using the McNemar test. Subjective confidence and confidence-weighted accuracy were compare using paired t tests. Agreement with the reference standard and interreader agreement were calculated using the kappa statistic and were compared using the z-test after bootstrapping was performed to obtain the standard error.With the traction view, the pooled accuracy increased from 44.9% to 72.4%, subjective confidence increased from 87% to 94%, and confidence-weighted accuracy increased from 51.7% to 74.3% (p0.001). With the traction view, the kappa statistic for agreement with the reference standard increased from 0.530 to 0.791 and from 0.381 to 0.625 for the two readers, and interreader agreement increased from 0.480 to 0.678 (p0.001).The addition of an internal rotation traction radiographic view significantly improves radiologist accuracy and confidence as well as interreader agreement in the classification of proximal femoral fractures, all of which would be expected to best guide appropriate surgical management.

Rationale and Objectives The purpose of this study was to integrate web-based forms with a zero-footprint cloud-based Picture Archiving and Communication Systems (PACS) to create a tool of potential benefit to radiology research and education. Materials and Methods Web-based forms were created with a front-end and back-end architecture utilizing common programming languages including Vue.js, Node.js and MongoDB, and integrated into an existing zero-footprint cloud-based PACS. Results The web-based forms application can be accessed in any modern internet browser on desktop or mobile devices and allows the creation of customizable forms consisting of a variety of questions types. Each form can be linked to an individual DICOM examination or a collection of DICOM examinations. Conclusions Several uses are demonstrated through a series of case studies, including implementation of a research platform for multi-reader multi-case (MRMC) studies and other imaging research, and creation of an online Objective Structure Clinical Examination (OSCE) and an educational case file.

To determine the prevalence of intra-articular gas (IAG) on elbow radiography and evaluate variables, including IAG, as predictors of UCL injury. This IRB-approved retrospective study consisted of 241 consecutive elbow radiographic studies containing AP radiographs with valgus stress of both symptomatic and asymptomatic sides in 234 patients. The IAG, medial joint space (MJS), and MJS difference between the symptomatic and asymptomatic elbow (MJSD) were evaluated by two readers, as well as patient age, gender, sport played, and handedness. Primary outcomes included IAG on valgus stress radiographs and UCL injury, which was determined by intraoperative findings as the reference standard or MRI if surgery was not performed. Univariate analysis with Student’s t, Fisher’s exact, and chi-square tests were performed. IAG only manifested with valgus stress and was demonstrated in 30/482 (6.2%) valgus stress radiographs in 27/234 (11.5%) patients. Overall, 21/241 (8.7%) valgus stress radiographs of the symptomatic elbow demonstrated IAG in 21 patients. A total of 128/241 (53.1%) elbow studies had evidence of UCL injury. MJS IAG (p = 0.0147) and increased MJSD (p = 0.0088) were significantly associated with UCL injury. Patient gender, age, handedness, laterality, sport played, and absolute MJS were not associated with UCL injury. MJS IAG with valgus stress demonstrates a sensitivity of 11.7% and specificity of 98.3% in detecting UCL injury for the symptomatic elbow. MJS IAG infrequently manifests on valgus stress radiographs, but is specific for UCL injury in the symptomatic elbow of overhead throwing athletes. MJS IAG and increased MJSD are significantly associated with UCL injury.

Hamstring muscle deficiency is increasingly recognized as a risk factor for anterior cruciate ligament (ACL) tears. The purpose of this study is to evaluate the vastus medialis to semimembranosus cross-sectional area (VM:SM CSA) ratio on magnetic resonance imaging (MRI) in patients with ACL tears compared to controls. One hundred knee MRIs of acute ACL tear patients and 100 age-, sex-, and side­matched controls were included. Mechanism of injury, contact versus non-contact, was determined for each ACL tear subject. The VM:SM CSA was measured on individual axial slices with a novel method using image-processing software. One reader measured all 200 knees and the second reader measured 50 knees at random to assess inter-reader variability. The intraclass correlation coefficient (ICC) was calculated to evaluate for correlation between readers. T-tests were performed to evaluate for differences in VM:SM CSA ratios between the ACL tear group and control group. The ICC for agreement between the two readers was 0.991 (95% confidence interval 0.984–0.995). Acute ACL tear patients have an increased VM:SM CSA ratio compared to controls (1.44 vs. 1.28; p = 0.005). Non-contact acute ACL tear patients have an increased VM:SM CSA ratio compared to controls (1.48 vs. 1.20; p = 0.003), whereas contact acute ACL tear patients do not (1.23 vs. 1.26; p = 0.762). Acute non-contact ACL tears are associated with increased VM:SM CSA ratios, which may imply a relative deficiency in hamstring strength. This study also demonstrates a novel method of measuring the relative CSA of muscles on MRI.

Stress fractures of the foot and ankle are a commonly encountered problem among athletes and individuals participating in a wide range of activities. This illustrated review, the second of two parts, discusses site-specific etiological factors, imaging appearances, treatment options, and differential considerations of stress fractures of the foot and ankle. The imaging and clinical management of stress fractures of the foot and ankle are highly dependent on the specific location of the fracture, mechanical forces acting upon the injured site, vascular supply of the injured bone, and the proportion of trabecular to cortical bone at the site of injury. The most common stress fractures of the foot and ankle are low risk and include the posteromedial tibia, the calcaneus, and the second and third metatarsals. The distal fibula is a less common location, and stress fractures of the cuboid and cuneiforms are very rare, but are also considered low risk. In contrast, high-risk stress fractures are more prone to delayed union or nonunion and include the anterior tibial cortex, medial malleolus, navicular, base of the second metatarsal, proximal fifth metatarsal, hallux sesamoids, and the talus. Of these high-risk types, stress fractures of the anterior tibial cortex, the navicular, and the proximal tibial cortex may be predisposed to poor healing because of the watershed blood supply in these locations. The radiographic differential diagnosis of stress fracture includes osteoid osteoma, malignancy, and chronic osteomyelitis.

We present two cases of pseudoaneurysm (PSA) about the shoulder mimicking more common clinical entities-soft tissue neoplasm and septic arthritis-for which biopsy of the mass and joint aspiration were requested respectively. We review the imaging findings of PSA with emphasis on findings in musculoskeletal protocol MRI, including the identification of pulsation artifact in both cases, which was critical to establishing the correct diagnosis. In the proper clinical setting, with imaging findings demonstrating a complex mass or fluid collection, MR images should be scrutinized for the presence of pulsation artifact, which can help diagnose a high-flow vascular lesion and avoid a potentially harmful invasive procedure such as biopsy.

Percutaneous musculoskeletal US-guided procedures are minimally invasive and allow real-time needle visualization, and some major uses of these procedures include injection of anesthetics and gluco...

OBJECTIVE. Variability in reports of the same imaging study performed at the same institution may be confusing to referrers and patients, hindering results communication. The purpose of this study was to introduce a quality improvement initiative aimed at reducing variation in radiology report templates at a large academic center. MATERIALS AND METHODS. The quality improvement initiative was undertaken at a large multisite, multidivision academic radiology practice performing more than 820,000 radiologic examinations annually. A project charter defined the goals, scope, and personnel of the initiative and an escalation pathway for conflict resolution. Standard requirements for templates were initially developed. From September 2017 to May 2018, an oversight committee (24 organ system and modality-based work groups with representatives from nine subspecialty divisions) reviewed and harmonized all institutional radiology report templates across the enterprise irrespective of the imaging site or division that interpreted the study. The primary outcome measure was percentage reduction in report templates after harmonization. The secondary outcome measure was monthly adherence to harmonized templates for 9 months after implementation assessed by manual review of 40 randomly selected reports per month. The paired t test was used to assess template reduction, and the chi-square trend test was used to study trend in adherence to harmonized templates. RESULTS. Among 19,687 total templates at baseline, 597 harmonized templates remained after harmonization (p < 0.001). There was variation in template reduction by work group (multiple p < 0.05; reduction range, 79.2-99.3%). Radiologist adherence to harmonized templates ranged from 88.0% to 100%, unchanged in the 9 months after implementation (p = 0.23, chi-square trend). CONCLUSION. A radiology report harmonization initiative reduced 97.0% of report templates with a sustained high degree of adherence to harmonized templates after implementation at a large multisite multidivision academic radiology practice.

Deep learning with convolutional neural networks (CNN) is a rapidly advancing subset of artificial intelligence that is ideally suited to solving image-based problems. There are an increasing number of musculoskeletal applications of deep learning, which can be conceptually divided into the categories of lesion detection, classification, segmentation, and non-interpretive tasks. Numerous examples of deep learning achieving expert-level performance in specific tasks in all four categories have been demonstrated in the past few years, although comprehensive interpretation of imaging examinations has not yet been achieved. It is important for the practicing musculoskeletal radiologist to understand the current scope of deep learning as it relates to musculoskeletal radiology. Interest in deep learning from researchers, radiology leadership, and industry continues to increase, and it is likely that these developments will impact the daily practice of musculoskeletal radiology in the near future.

Injuries to the syndesmotic ligaments of the ankle or "high ankle sprains" are common in acute ankle trauma but can be difficult to diagnose both clinically and on imaging. Missed injuries to the syndesmosis can lead to chronic ankle instability, which can cause persistent pain and lead to early osteoarthritis. This review will illustrate the anatomy of the syndesmotic ligamentous complex, describe radiographic, CT, and MR imaging of the syndesmosis, demonstrate typical mechanisms of injuries and associated fracture patterns, and provide an overview of important management considerations.

This chapter discusses distal radius fractures, which are one of the most commonly encountered orthopedic injuries and cause significant pain in both the nonoperative and operative setting. Regional anesthesia, administered commonly in the form of brachial plexus blocks, provides for reliable analgesia during closed reduction, operative fixation, and the postoperative period. Complications related to distal radius fractures include carpal tunnel syndrome, compartment syndrome, symptomatic malunion, persistent wrist pain, and complex regional pain syndrome (CRPS). Following distal radius fracture management, follow-up is warranted for the development of CRPS, for which a variety of pharmacologic and interventional therapies may be considered.

Lipohemarthrosis is well known to be associated with intra-articular fractures throughout the body. Despite the relatively common occurrence of hip fracture and the frequency of communication between the hip joint and iliopsoas bursa, to the best of our knowledge, a fat-fluid level involving the iliopsoas bursa secondary to a hip fracture has not previously been reported. The following is a case report of a 48-year-old male who sustained an acute femoral neck fracture and was found to have distension of the iliopsoas bursa with a fat-fluid level resulting from extra-capsular extension of a lipohemarthrosis. The imaging findings, relevant anatomy, and potential importance of this finding for the detection of hip fracture are discussed.

Standard computed tomography windows are limited in the thorax because they can only display 1 tissue at a time. Computed tomography window blending allows for simultaneous viewing of all 3 tissues in a single image, which may improve evaluation of diseases that contiguously affect multiple compartments. In this article, we use examples to illustrate the utility of window blending in aggressive infections, metastatic cancer, and penetrating trauma.

Retro-odontoid pseudotumor, or mass-like retro-odontoid soft tissue thickening, is an uncommon but important imaging finding that may be associated with rheumatoid arthritis, crystal deposition diseases, as well as non-inflammatory conditions such as cervical degenerative changes and mechanical alterations. Retro-odontoid pseudotumor is commonly associated with atlantoaxial microinstability or subluxation. MRI and CT have an important role in the detection and diagnosis of retro-odontoid pseudotumor. However, due to a wide range of imaging characteristics and ambiguous etiology, it is a frequently misunderstood entity. The purpose of this article is to review relevant anatomy of the craniocervical junction; describe various imaging appearances, pathophysiology and histology in both rheumatoid and non-rheumatoid etiologies; and discuss differential diagnosis of retro-odontoid pseudotumor in order to help guide clinical management.

The purpose of this study was to demonstrate the diagnostic performance and effect on reader confidence of a custom computed tomography (CT) color postprocessing algorithm for assessment of nondisplaced proximal femoral fractures. Four radiologists, including two PGY-3 radiology residents and two emergency radiologists, independently interpreted 30 CT examinations of the hip and/or pelvis performed for trauma, consisting of a total of 15 cases positive for nondisplaced hip fracture and 15 age and sex-matched controls. Images were reviewed first with conventional CT images and after at least 8 weeks, all images were reviewed again with the addition of coronal color postprocessed images. Sensitivity and specificity were compared with McNemar’s test, and diagnostic confidence was compared with paired t tests. There was no significant difference in diagnostic performance between conventional and postprocessed images, although there was nominally increased sensitivity and decreased specificity with the postprocessed images: for all readers, the sensitivity and specificity for conventional images was 88.3 and 95.0%, compared to 93.3% (p = 0.25) and 88.3% (p = 0.14) for postprocessed images. Three of four readers (including both attending radiologists) reported an increase in confidence with postprocessed images for cases negative for fracture (10-point confidence scale of 7.25 for conventional images, compared to 8.2 for postprocessed images for all readers, p = 0.0053). There was no difference in diagnostic confidence for cases positive for fracture. A custom color CT postprocessing algorithm did not demonstrate a significant difference in diagnostic performance for assessment of nondisplaced proximal femoral fractures within the limitations of a relatively small sample size; however, postprocessing increases confidence of experienced readers in cases negative for fracture.

To summarize relevant anatomy, imaging, and treatment of hip fractures, and to synthesize a treatment-based approach for description and classification of hip fractures. Hip fractures are predominantly seen in the elderly, where they are increasing in incidence, and can substantially reduce healthy life-years. The osseous and vascular anatomy of the proximal femur can help to understand the clinical implications of various types of hip fracture. Radiographs are the principal imaging modality for assessment of hip fracture, although there is a clear role for CT and MRI for assessment of radiographically occult fractures. There are multiple classifications of hip fractures in the orthopedic literature; however, these are not commonly used in clinical practice due to complexity, poor reported inter-observer agreement, and relatively few methods of surgical fixation. A simplified anatomic and treatment-based approach to hip fractures can help guide image interpretation and clinical management.

To determine the effect of needle position and foraminal stenosis on contrast flow directionality during CT-guided transforaminal epidural steroid injections (TFESI). One hundred five consecutive CT-guided injections were performed in 68 patients (mean age, 65.5 years) from January 1 to December 31 2017, all with preceding MRI. Two readers independently reviewed CT images to assess needle position and to determine direction of contrast flow, which was defined as central or peripheral. The MRIs were independently reviewed by the readers to determine the degree of foraminal stenosis. Inter-reader agreement for both was evaluated with the kappa statistic. Analyses were performed to determine effect of needle position, degree of foraminal stenosis, and volume of contrast injected with directionality of contrast flow, and association between contrast flow directionality with immediate post-procedural pain scores. Central direction of contrast flow was demonstrated in 41/78 (52.6%) of cases with posterolateral needle position, and 20/27 (74.1%) with central or anteromedial needle position (p = 0.07). There was no difference in direction of contrast flow with high-grade versus absence of high-grade neuroforaminal narrowing, or with volume of contrast injected. There was no difference in immediate post-procedure pain scores regardless of contrast flow directionality. Needle position is not significantly associated with contrast flow directionality during CT-guided TFESI, although there was a trend towards relatively decreased central flow with posterolateral positioning. Degree of foraminal stenosis and volume of injected contrast did not affect contrast flow directionality. There was no difference in immediate post-procedural pain scores with either direction of contrast flow.

The purpose of this study was to evaluate the diagnostic performance of CT for assessment of occult fractures of the proximal femur, pelvis, and sacrum. A retrospective review was performed on patients who received a CT of the hip or pelvis for suspected occult fracture after negative or equivocal radiographs performed within 24 h. The official radiology report was utilized for the determination of CT findings and calculation of sensitivity and specificity. Surgical reports, MRI reports, and clinical follow-up were used as the standard of reference. Sensitivity and specificity were calculated with 95% confidence intervals. Seventy-four patients received CT of the hip or pelvis for clinical concern for occult fracture after negative or equivocal radiographs. By the reference standard, a total of 40 fractures were present in 25/74 (33.8%) patients, including 35 conservatively treated fractures of the greater trochanter, pelvis, and sacrum, and 5 operatively treated proximal femoral fractures. A total of 14/74 (18.9%) of patients had an MRI within 1 day of CT. MRI identified an operatively treated femoral neck fracture not seen on CT and an operatively treated intertrochanteric fracture, which CT described as a greater trochanteric fracture. There were two false negative conservatively treated pelvic fractures not seen on CT but diagnosed on MRI. On a per-patient basis, CT had an overall sensitivity of 88% (22/25; 95% confidence intervals 69–97%), specificity of 98% (48/49; 95% confidence intervals 89–100%), and negative predictive value of 94%. For the five operative proximal femoral fractures, the sensitivity of CT was 60% (3/5; 95% confidence intervals 15–95%), specificity was 99% (68/69; 95% confidence intervals 92–100%), and negative predictive value was 97%. In the clinical setting of suspected occult fracture, the sensitivity of clinical CT reports for detection of any type of fracture of the proximal femur, pelvis, or sacrum was 88%. For the small number of operatively treated proximal femoral fractures seen in the study, sensitivity of CT was 60% (3/5) and negative predictive value was 97%, although the relatively few patients needing fixation precludes statistical analysis.