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Popa D, Medak A, Chin W, Huchim-Lara O, Fliszar E, Hughes T, Grover I. Dysbaric osteonecrosis (DON) among the artisanal diving fishermen of Yucatán, Mexico. Diving and Hyperbaric Medicine. 2020 December 20;50(4):391–398. doi: 10.28920/dhm50.4.391-398. PMID: 33325021.) Introduction: Artisanal diving fishermen in Yucatán, Mexico have high rates of decompression sickness as a result of frequently unsafe diving practices with surface supplied compressed air. In this study, we investigated the prevalence of dysbaric osteonecrosis (DON), a type of avascular necrosis, in the most susceptible joints in a cohort of these fishermen. Methods: We performed radiographs of bilateral shoulders, hips, and knees of 39 fishermen in Mexico and surveyed them about their medical and diving histories. We performed pairwise correlations to examine if the fishermen’s diving behaviours affected the numbers of joints with DON. Results: The radiographs revealed Grade II or higher DON in 30/39 (76.9%) of the fishermen. Twenty-two of 39 fishermen (56.4%) had at least two affected joints. The number of joints with DON positively correlates with the lifetime maximum diving depth and average bottom time. Conclusions: These findings represent among the highest prevalence rates of DON in divers and reflect the wide-spread scale of decompression sickness among these fishermen. Through this work, we hope to further educate the fishermen on the sequelae of their diving with the aim of improving their diving safety.

Intramuscular myxomas are benign soft-tissue tumors, characterized by bland spindle-shaped cells and fibroblasts within an abundant mucoid matrix on histologic examination. Classically, these are slowly enlarging masses which may occasionally cause pain, paresthesia, and muscle weakness secondary to mass effect. We present an interesting phenomenon of two histologically confirmed cases of intramuscular myxomas that exhibited size and enhancement changes on follow-up imaging after image-guided biopsy. To our knowledge, this is the first report to describe size and enhancement changes of intramuscular myxomas after biopsy.

Author(s): von Drygalski, Annette; Moore, Randy E; Nguyen, Sonha; Barnes, Richard FW; Volland, Lena M; Hughes, Tudor H; Du, Jiang; Chang, Eric Y | Abstract: OBJECTIVES:Point-of-care musculoskeletal ultrasound (US) is increasingly used by hemophilia providers to guide management; however, pathologic tissue differentiation with US is uncertain. We sought to determine the extent to which point-of-care musculoskeletal US can identify and discriminate pathologic soft tissue changes in hemophilic arthropathy. METHODS:Thirty-six adult patients with hemophilia A/B were prospectively enrolled. Point-of-care musculoskeletal US examinations were performed on arthropathic joints (16 knees, 10 ankles, and 10 elbows) using standard views by a musculoskeletal US-trained and certified hematologist, who recorded abnormal intra-articular soft tissue accumulation. Within 3 days, magnetic resonance imaging was performed using conventional and multiecho ultrashort echo time sequences. Soft tissue identification (synovial proliferation with or without hemosiderin, fat, and/or blood products) was performed by a musculoskeletal radiologist. Findings obtained with both imaging modalities were compared and correlated in a blinded fashion. RESULTS:There was perfect agreement between the modalities on the presence of abnormal soft tissue (34 of 36 cases). However, musculoskeletal US was unable to discriminate between coagulated blood, synovium, intrasynovial or extrasynovial fat tissue, or hemosiderin deposits because of wide variations in echogenicity. CONCLUSIONS:Musculoskeletal US is valuable for point-of-care imaging to determine the presence of soft tissue accumulation in discrete areas. However, because of limitations of musculoskeletal US in discriminating the nature of pathologic soft tissues and detecting hemosiderin, magnetic resonance imaging will be required if such discrimination is clinically important.

Rationale and Objectives There has been waxing and waning of popularity of radiology as a career choice over the last few years. These fluctuations may in part be due to misconceptions such as the perceived lack of patient contact, as well as the perception of decreasing numbers of entry-level jobs. To address such misconceptions, it is important to reach medical students early in their training, both to give them a comprehensive and balanced understanding of radiology practice, and to appropriately frame radiologists as clinicians. Realizing the benefits of direct student outreach, a number of medical specialties are moving toward more direct recruitment efforts often through student interest groups and career fairs. The Medical Student Radiology Expo (MSRE) was proposed and executed by the Alliance of Medical Students Educators in Radiology, which was supported by the Association of University Radiologists (AUR) and the American College of Radiology. The MSRE was held immediately after the 2016 AUR annual meeting and hosted at the Moores Cancer Center at the University of California, San Diego. The goals of the MSRE were threefold: (1) to showcase radiology as a distinct and exciting specialty to all medical students, (2) to foster an interest in pursuing a career in radiology among medical students, and (3) to create a distributable and customizable combined symposium and workshop that could be easily replicated elsewhere. Methods The activities of this 1-day expo started with a morning of didactic elements, including a session identifying inaccurate myths surrounding radiology, specific details of interest pertaining to diagnostic radiology and interventional radiology residency programs, followed by interactive imaging diagnosis games, and question and answer sessions. A casual lunch with faculty members and attendees provided for more sustained direct and informal interactions between the students and the faculty. During the afternoon sessions, students participated in hands-on workshops, including ultrasound, imaging-guided biopsies, catheter manipulation, and post-processing image analysis, as well as roundtable discussions about radiology with the faculty. Results The results from the post-program survey of the medical students were overall positive. Conclusions The MSRE, with the combined efforts of multiple organizations, was successful. A customizable, modular toolkit has been posted on the AUR website. Using this toolkit as a template, this recruitment and informational activity can be replicated at individual institutions, local radiology chapters, multidisciplinary meetings, and radiology meetings.

Introduction and Objectives Intra-articular corticosteroid injections are standard of care for managing joint pain secondary to osteoarthritis or rheumatoid arthritis but are rarely used in haemophilic arthropathy. We have introduced and evaluated the efficacy and safety of ultrasound-guided corticosteroid injections for pain relief in patients with haemophilic arthropathy. Patients and methods Ultrasound-guided intra-articular injections performed on haemophilia patients at UCSD between March 2012 and January 2016 were analysed. Needle placement and injection (40 mg triamcinolone; 3–5 mL lidocaine) were performed with musculoskeletal ultrasound and Power Doppler. Analysis included patient demographics, joint-specific parameters such as tissue hypervascularity and effusions, pain relief, and procedure-associated complications. Results Forty-five injections (14 ankles, 13 elbows, 18 knees) were administered in 25 patients. Advanced arthropathy with hypervascularity and/or effusions was present in 91% and 61% of joints, respectively. Ninety-one per cent of injections resulted in pain relief which was significant in 84% (>30% reduction). Median pain score was reduced from 7 of 10 to 1 of 10 (P < 0.001), usually within 24 h. Median duration of pain relief was 8 weeks (range 1–16 weeks). Haemophilia B patients experienced longer periods of relief, and high Pettersson scores were associated with shorter duration of relief. There were no procedure-associated complications. Repeat ultrasound of eight joints within 4 weeks of injection demonstrated nearly complete resolution of hypervascularity. Conclusions Point-of-care ultrasound enabled intra-articular corticosteroid injections that provided highly effective, safe, and relatively long-lasting pain relief in haemophilic arthropathy. This approach should be used to improve pain management in haemophilic arthropathy.

Objectives Musculoskeletal ultrasound (US) is used increasingly to examine hemophilic arthropathy. However, quantitative algorithms to document findings are lacking. We developed and sought to validate a protocol quantifying hemophilic joint abnormalities. Methods Thirty-one patients with hemophilia were examined serially for 2 years with musculoskeletal US (≈600 joint examinations and ≈6000 images). Based on the spectrum of pathologies, a quantitative algorithm, named Joint Tissue Activity and Damage Examination (JADE), was developed for soft tissue and osteochondral measurements, including power Doppler, using nominal group techniques. To study intra- and inter-rater reliability, 8 musculoskeletal US-experienced hemophilia providers performed anatomic landmark recognition and tissue measurements on 86 images with arthropathic changes, with repetition 1 month later. Twenty-three musculoskeletal US-inexperienced providers performed similar assessments. Inter-operator reliability was established by 6 musculoskeletal US-experienced hemophilia providers, each acquiring images and JADE assessments of 3 hemophilic arthropathic joints. A radiologist and musculoskeletal sonographer functioned as adjudicators. The statistical analysis was performed with the intraclass correlation coefficient (ICC), Fleiss κ, and Cohen κ where appropriate. Results The musculoskeletal US-experienced providers showed excellent intra-and inter-rater reliability for tissue measurements (ICCs, 0.94-0.96). Agreement was good to excellent for landmark recognition (Fleiss κ, 0.87-0.94). Inter-operator reliability was excellent for measurements and landmark recognition (ICC, 0.90; Fleiss κ, 1.0). Agreement with adjudicators was mostly good to excellent. Musculoskeletal US-inexperienced providers showed excellent inter-rater reliability for measurements (ICC, 0.96) and moderate agreement for landmark recognition (Fleiss κ, 0.58). Conclusions The JADE protocol appears feasible for quantifying hemophilic intra-articular abnormalities. Musculoskeletal US-trained hemophilia providers showed high intra-rater, inter-rater, and inter-operator reliability, supporting JADE as a protocol for clinical management and research.

Hemophilic arthropathy is a debilitating condition that can develop as a consequence of frequent joint bleeding despite adequate clotting factor replacement. The mechanisms leading to repeated spontaneous bleeding are unknown. We investigated synovial, vascular, stromal, and cartilage changes in response to a single induced hemarthrosis in the FVIII-deficient mouse. We found soft-tissue hyperproliferation with marked induction of neoangiogenesis and evolving abnormal vascular architecture. While soft-tissue changes were rapidly reversible, abnormal vascularity persisted for months and, surprisingly, was also seen in uninjured joints. Vascular changes in FVIII-deficient mice involved pronounced remodeling with expression of α-Smooth Muscle Actin (SMA), Endoglin (CD105), and vascular endothelial growth factor, as well as alterations of joint perfusion as determined by in vivo imaging. Vascular architecture changes and pronounced expression of α-SMA appeared unique to hemophilia, as these were not found in joint tissue obtained from mouse models of rheumatoid arthritis and osteoarthritis and from patients with the same conditions. Evidence that vascular changes in hemophilia were significantly associated with bleeding and joint deterioration was obtained prospectively by dynamic in vivo imaging with musculoskeletal ultrasound and power Doppler of 156 joints (elbows, knees, and ankles) in a cohort of 26 patients with hemophilia at baseline and during painful episodes. These observations support the hypothesis that vascular remodeling contributes significantly to bleed propagation and development of hemophilic arthropathy. Based on these findings, the development of molecular targets for angiogenesis inhibition may be considered in this disease.

Point-of-care musculoskeletal ultrasound (US) is increasingly used by hemophilia providers to guide management; however, pathologic tissue differentiation with US is uncertain. We sought to determine the extent to which point-of-care musculoskeletal US can identify and discriminate pathologic soft tissue changes in hemophilic arthropathy.Thirty-six adult patients with hemophilia A/B were prospectively enrolled. Point-of-care musculoskeletal US examinations were performed on arthropathic joints (16 knees, 10 ankles, and 10 elbows) using standard views by a musculoskeletal US-trained and certified hematologist, who recorded abnormal intra-articular soft tissue accumulation. Within 3 days, magnetic resonance imaging was performed using conventional and multiecho ultrashort echo time sequences. Soft tissue identification (synovial proliferation with or without hemosiderin, fat, and/or blood products) was performed by a musculoskeletal radiologist. Findings obtained with both imaging modalities were compared and correlated in a blinded fashion.There was perfect agreement between the modalities on the presence of abnormal soft tissue (34 of 36 cases). However, musculoskeletal US was unable to discriminate between coagulated blood, synovium, intrasynovial or extrasynovial fat tissue, or hemosiderin deposits because of wide variations in echogenicity.Musculoskeletal US is valuable for point-of-care imaging to determine the presence of soft tissue accumulation in discrete areas. However, because of limitations of musculoskeletal US in discriminating the nature of pathologic soft tissues and detecting hemosiderin, magnetic resonance imaging will be required if such discrimination is clinically important.

Objective Hemophilic arthropathy is associated with pronounced vascular joint remodeling. Also, compared to the general population, PWH have a higher prevalence of hypertension not explained by usual risk factors. Since vascular remodeling in various vascular beds is a hallmark of hypertension, we hypothesized that vascular joint remodeling is associated with elevated blood pressures and hypertension. Methods Elbows, knees and ankles of 28 adult PWH were evaluated for vascular abnormalities with MSKUS/PD, as well as for radiographic and clinical status and pain. Logistic and linear regression models were fitted to examine associations between hypertension, blood pressure and PD score. Results The extent of vascular abnormalities was associated with hypertension and blood pressures. Hypertensive patients had a higher PD score compared to non-hypertensive patients and the risk of hypertension increased steeply with PD score. SBP was also strongly associated with PD score, while DBP was only weakly associated. Conclusions Vascular remodeling in hemophilic joints is associated with hypertension and elevated blood pressures. Since hypertension is a grave risk factor for intracranial hemorrhage, a prominent cause of mortality in hemophilia patients, future studies are needed to address the causal pathways between vascular joint remodeling and blood pressure. This article is protected by copyright. All rights reserved.

Purpose To correlate ankle and foot fracture patterns with the presence of tenosynovial fat on computed tomography (CT). Materials and Methods In this retrospective, cross-sectional, observation study, two blinded musculoskeletal radiologists independently reviewed 89 CT scans of patients with ankle or foot fractures and recorded the presence of fat about Henry’s knot, tibialis posterior tendon, and peroneus longus tendon. Results The agreement between the two readers ranged from excellent to substantial. Sixteen to 23 percent of fractures were associated with tenosynovial fat. Conclusions The finding of tenosynovial fat following ankle or foot trauma warrants a closer search for a fracture.

Introduction: Acute painful joint episodes in hemophilia are not always associated with hemarthrosis. Point-of-Care Musculoskeletal Ultrasound with Power Doppler (POC MSKUS/PD) is a fast and sensitive imaging modality to determine the presence of hemarthrosis and direct management. Systemic collagen cleavage products reflecting extracellular matrix, bone and soft tissue turnover may serve as an alternative tool for the detection of hemarthrosis. Based on previous observations of pronounced vascular remodeling within the synovial tissue during hemarthrosis in patients and hemophilic mouse models, we hypothesized that cleavage products of collagen IV, found in the basement membrane of blood vessels may differentiate between bleeding and non-bleeding states. Methods: Joint bleeding was induced in FVIII-/- mice (+/- FVIII-treatment before and shortly after injury). Synovial vascular remodeling was assessed 14 days later by MSKUS/PD and histology including αSmooth Muscle Actin (αSMA)-staining. Murine plasma samples were analyzed for C4M2 and P4NP-7S, which are type IV collagen turnover products. To determine human relevance, 31 adult patients with hemophilia (PWH), ≥ age 21, were studied prospectively for 3 years with MSKUS/PD during pain-free intervals and painful events for bleed status, vascular flow and 11 plasma markers of collagen turnover(C2M, ARGS, C3M, Pro-C3, C5M, Pro C5, C4M2, P4NP-7S, Col18N, DCN- CS, ColNeo10, NIC). Results: Type IV collagen turn-over markers were significantly elevated in plasma of FVIII-/- deficient mice 14 days after joint bleeding when compared to baseline (C4M2: 2.575 ng/mL vs. 1.94 ng/mL, p=0.029 and P4NP-7S: 80.3 ng/mL vs. 67.81 ng/mL, p= 0.0152 respectively ). This increase coincided with a significant increase in vessel number (2.3 fold, p=0.0008), vascular flow by PD (2.3 fold, p= 0.014) and αSMA staining (5.1 fold, p= 0.0007). C4M2 and P4NP7S plasma levels correlated negatively with αSMA staining, suggesting a role for αSMA in vessel stabilization (C4M2 p=0.02, Pearson r= -0.5707; P4NP-7S p= 0.0130, Pearson r= -0.6238). FVIII-treatment reduced plasma C4M2 and P4NP-7S levels to baseline (C4M2 1.98 ng/mL vs. 1.94 ng/mL, P4NP-7S 59.98 ng/mL vs. 67.81 ng/mL), but had no effect on the other vascular parameters. In patients, results from 91 visits were compiled. Twenty five were due to acute painful episodes with 16 confirmed hemarthroses. Of the 11 biomarkers evaluated, only C4M2 and P4NP-7S were transiently but significantly elevated in plasma during joint bleeding compared to pain free intervals or to non-bleeding painful episodes. Plasma C4M2 levels during acute painful bleeding episodes when compared to non-bleeding states were 41.65 vs. 29.69 ng/mL (p=0.0003), and P4NP-7S levels were 418.9 vs 278.1 ng/mL (p=0.0007), respectively. Baseline levels of C4M2 and P4NP-7S in PWH were above the lab reported normal range, indicating ongoing high vascular basement membrane turnover. Additionally, PWH who developed joint bleeding episodes had a higher level of collagen IV biomarkers at baseline when compared to PWH who did not experience joint bleeding (C4M2 33.91 vs 29.07 ng/mL, P4NP7s 320.6 vs 292.8 ng/mL), although this was not statistically significant. Hemarthrosis was accompanied by pronounced abnormal synovial microvascular flow evidenced by PD, while plasma levels of both biomarkers correlated positively with joint PD signal (C4M2, p= 0.0400, Pearson r=0.4409; P4NP7S-p=0.0141, Pearson r=0.5154). Conclusions: Our findings suggest that systemic vascular collagen turn-over products may be novel biomarker candidates to identify patients at high risk for joint bleeding and to diagnose acute hemarthrosis. Hemarthrosis in hemophilia is associated with pronounced synovial vascular remodeling. Cleavage products of type IV collagen, but not of any other collagen, were systemically elevated in PWH and distinguished bleeding from non-bleeding painful episodes. Type IV collagen is found exclusively in basement membranes and in the case of joint bleeding, the presumed source of these turnover markers is newly formed synovial blood vessels. Therefore, our findings support the concept that vascular instability during neovascularization is involved in the dynamics of hemophilic joint bleeding. These findings broaden the scope of potential diagnostic tools substantially, opening new avenues for personalized treatment of PWH. Disclosures von Drygalski: Bioverativ/Sanofi: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Novo Nordisk: Consultancy, Honoraria; HemaBiologics: Consultancy; Genentech: Consultancy; Biomarin: Consultancy, Honoraria; Uniqure: Consultancy, Honoraria; Shire: Consultancy, Honoraria; Hematherix: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.

Objective.To assess whether inflammation on ultrasound is predictive of clinical response to intraarticular (IA) corticosteroid injections in patients with knee osteoarthritis (OA).Methods.Patients with symptomatic knee OA were randomized to receive either an IA injection of 40 mg triamcinolone acetonide in the treatment group or 1 cc 0.9% saline in the placebo group. Clinical response was assessed by changes in baseline Western Ontario and McMaster Universities (WOMAC) index scores and physician global assessment at 4 and 12 weeks. Ultrasounds were performed at each visit. Patients and assessors were blinded to treatment status.Results.Seventy-nine patients were enrolled into the study. Four-week data were available for 67 patients in the primary analysis comparing change in WOMAC pain score from baseline to 4 weeks. There was almost no change in the WOMAC pain subscale score from baseline to 4 weeks in the control group, but there was a significant improvement in WOMAC pain subscale score from 10.8 (SD ± 3.2) at baseline to 8.75 (SD ± 4.0) at 4 weeks in the treatment group (adjusted p = 0.001). Of the 34 patients in the treatment group; 16 (47%) had inflammatory disease and 18 (53%) had noninflammatory disease as determined by ultrasound. There was no difference in the change in WOMAC pain score between the inflammatory and noninflammatory patients in the treatment group at 4 weeks. There was a statistically significant greater improvement in pain subscale scores among noninflammatory patients than among inflammatory patients at 12 weeks.Conclusion.Intraarticular corticosteroid injections are an effective short-term treatment for symptomatic knee OA compared to placebo. Patients with noninflammatory characteristics on ultrasound had a more prolonged benefit from IA corticosteroids compared to inflammatory patients.

Objective: The objective of this study was to demonstrate the anatomical features of metacarpal heads that can simulate bone erosions. Materials and Methods: After performing computed tomography scanning of 6 cadaveric hand specimens, normal anatomy was identified; the maximum depth, height, and area of the osseous concavities in the ulnar, radial, and intersesamoid aspects of the metacarpal heads were measured. An average value was determined for each of the measurements of the 5 fingers, and statistical analysis was done. Results: Three concavities were identified in the first metacarpal head (intersesamoid, ulnar, and radial) and 2 in the others fingers (ulnar and radial). All of them had sharp regular margins without sclerotic reaction. The measurements of these concavities were done. Conclusions: We analyzed the normal osseous anatomy of the metacarpal heads. Knowledge of this normal anatomy enables the radiologist to differentiate normal concave regions from bone erosions that accompany a variety of synovial inflammatory diseases.

The purpose of our study was to characterize and describe normal osseous contours of the metatarsal heads that may simulate erosive changes.CT of the metatarsal heads was performed in six human cadaveric feet, and 3D reformatted images were analyzed. Subsequently, five feet were sectioned in planes corresponding to those at imaging for anatomic correlation, and one foot was anatomically dissected for correlation. The normal anatomic osseous contours of the metatarsal heads were analyzed and described.Normal osseous anatomy of the greater (first) and lesser (second through fifth) metatarsal heads was identified. The normal osseous landmarks that simulate erosive changes were identified. Variations in the normal anatomic osseous contours, including those related to the medial and lateral condyles, were present in all specimens. The lateral condyle of the first metatarsal head was found to be more prominent than the medial condyle. In addition, anatomic variations in the normal osseous concavities of the lateral and medial aspects of each metatarsal head were measured. An intersesamoidal ridge, present on the plantar surface of the first metatarsal head, was identified in all specimens.The normal anatomic contours of the metatarsal head are a potential major source for diagnostic error when viewing sectional CT and MR images in patients with suspected erosive arthritis. These normal variations, although common and varied, produce characteristic findings that can be differentiated from bone erosions.

Neurogenic tumors account for approximately 10–12% of all benign soft tissue tumors and 7–8% of all malignant soft tissue tumors. These can be divided into neoplastic and pseudotumors. Neoplastic tumors include those derived from the Schwann cell (collectively referred to as “peripheral nerve sheath tumors” or PNSTs), such as neurilemoma, neurofibroma, and rare malignant counterparts. Another neurogenic tumor is the neural fibrolipoma. This is likely to be congenital in origin and presents as fibrofatty infiltration of the nerve, usually the median nerve at the wrist. Following trauma or surgery a neuroma may develop at the site of injury. Tumors may also develop from peripheral autonomic nerves; an example of this is the glomus tumor, commonly seen beneath the fingernail in women.

The Medical Imaging Resource Center (MIRC) software of the Radiological Society of North America is used to share teaching files and clinical trial data. By using the MIRC service for clinical trials, teaching file cases can be automatically generated directly from picture archiving and communication systems (PACS). The advantage of using the clinical trials service over the authoring service is the need for minimal user intervention, because data already present in the Digital Imaging and Communications in Medicine (DICOM) header can be automatically inserted into teaching file cases. When reading a case on the PACS workstation, the radiologist needs only to select the images for the teaching file case, write the diagnosis in the “Study Comments” box (usually used for “wet” readings), and send the case to the MIRC server directly from the workstation. The MIRC server automatically makes the images anonymous and fills in the modified teaching file template by using the data in the DICOM header (patient ag...

Erdheim-Chester disease (ECD) is a rare form of non-Langerhans cell histiocytosis characterized by xanthogranulomatous infiltration of foamy histiocytes frequently involving bone and other organ systems. We herein report a unique case of ECD discovered incidentally in an explanted liver in a 65-year-old male with end-stage liver disease secondary to hepatitis C cirrhosis. Histological examination and immunohistochemical studies in the explanted liver revealed prominent foamy histiocytes that were CD68 positive, but CD1a and S100 negative. Mutational hotspot analysis of the explanted liver using a panel of 47 most common cancer-related genes performed by next generation sequencing (NGS) revealed likely somatic mutations in the PDGFRA, PTEN, and HNF1A genes, but no BRAF codon 600 mutations were detected. The bone marrow showed similar findings as in the liver. Whole body PET and bone scans demonstrated increased heterogeneous uptake in bilateral humeral and femoral diaphysis, most compatible with ECD. To our knowledge, this is the first case report of ECD that involves mainly bone marrow and liver with novel genomic alterations. Our case highlights the diversity and complexity of this disease entity and the importance of multi-modality approach integrating clinical and radiologic features with histopathologic and molecular/genomic findings.

Hemophilic arthropathy is a debilitating condition that can develop as a consequence of frequent joint bleeding despite adequate clotting factor replacement. The mechanisms leading to repeated spontaneous bleeding are unknown. We investigated synovial, vascular, stromal and cartilage changes in response to a single induced hemarthrosis in the FVIII-deficient mouse. We found soft tissue hyperproliferation with marked induction of neoangiogenesis and evolving abnormal vascular architecture. While soft tissue changes were rapidly reversible, abnormal vascularity persisted for months and, surprisingly, was also seen in uninjured joints. Vascular changes in FVIII-deficient mice involved pronounced remodeling with expression of α-Smooth Muscle Actin (SMA), Endoglin (CD105) and vascular endothelial growth factor, as well as alterations of joint perfusion as determined by in vivo imaging. Vascular architecture changes and pronounced expression of α-SMA appeared unique to hemophilia, as these were not found in joint tissue obtained from mouse models of rheumatoid arthritis (RA) and osteoarthritis (OA) and from patients with the same conditions. Evidence that vascular changes in hemophilia were significantly associated with bleeding and joint deterioration was obtained prospectively by dynamic in vivo imaging with musculoskeletal ultrasound and power Doppler of 156 joints (elbows, knees and ankles) in a cohort of 26 patients with hemophilia at baseline and during painful episodes. These observations support the hypothesis that vascular remodeling contributes significantly to bleed propagation and development of hemophilic arthropathy. Based on these findings, the development of molecular targets for angiogenesis inhibition may be considered in this disease.

MR arthrography combines the techniques of arthrography with MR imaging to benefit from the added imaging information afforded by intra-articular distention. This article reviews technical considerations for MR arthrography, potential complications, indications, pitfalls in imaging diagnosis, and commonly encountered pathology. It is an elegant study that can offer precise diagnostic information in the appropriate clinical setting.

Background: We describe the topographic anatomy of the lateral ligament complex of the ankle using 3-dimensional (3D) computed tomography (CT) imaging. Methods: Dissection of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) was performed on 8 unpaired fresh-frozen cadaver feet. Ligaments were sharply dissected from bone, and the footprint was outlined with radio-opaque paint. The specimen underwent a 0.625-mm slice CT scan of the ankle with 3D reconstructions. Software was used to determine the surface area of the ligament footprint as well as measure the distance from the peroneal tubercle to the center of the CFL footprint. Data are presented as mean ± standard error. Results: Six specimens had a bifid ATFL. Seven ankles had a bifid ATFL footprint on the talus. All specimens had intact CFL fibers. The intact superior and inferior limbs of the ATFL measured 19.7 ± 1.2 mm and 16.7 ± 1.1 mm. The CFL measured 24.8 ± 2.4 mm. The area of the footprints of the superior ATFL and inferior ATFL on the talus measured 1.5 ± 0.26 cm2 and 0.90 ± 0.07 cm2. The CFL and ATFL origins on the fibula were continuous and measured 3.48 ± 0.39 cm2. The CFL insertion on the calcaneus measured 2.68 ± 0.20 cm2. The CFL was found 27.1 ± 1.0 mm posterior and superior from the peroneal tubercle. Conclusions: In presumably uninjured specimens, both the ATFL and its footprint on the talus were bifid. The CFL and ATFL origins have a single confluent footprint on the anterior border of the distal fibula. The CFL footprint on the calcaneus is almost 3 cm posterior and superior to the peroneal tubercle. Clinical Relevance: This study may assist surgeons in anatomically reconstructing the lateral ligament complex of the ankle.

The magnetic resonance imaging (MRI) scans of 26 patients with histopathologically proven pigmented villonodular synovitis (PVNS), involving joints but excluding tendon sheaths, were reviewed retrospectively. The purpose of this study is to define the spectrum and frequency of MRI characteristics for PVNS using conventional spin echo (in two cases before and after intravenous administration of gadopentate dimeglumine) and also gradient echo techniques. A cystic variety is presented, the MRI appearances of which have not been found in a review of the literature.

Nonunion of the posterior arch of the atlas is an uncommon but normal developmental variant. It is usually asymptomatic in the patient but may be associated with greater incidence of fracture because of increased stress on the anterior arch.We sought to determine whether anterior arch hypertrophy is present in cases of congenital nonunion of the posterior arch of the atlas.A retrospective analysis of 1 year (February 2005-January 2006) of computed tomography cervical spine studies requested by the University of California San Diego Medical Center Trauma Department was undertaken.All patients matching the search criteria (see Study design) were included.Area density product, defined as the midline cross-sectional area of the anterior arch on sagittal reformat multiplied by the average areal radiodensity in Hounsfield units (HU) as measured by two raters, was calculated for cases and controls.Cases of posterior arch nonunion were identified and matched to controls. The significance of differences in area density product between cases and controls were established by the Student t test. Interrater correlation was calculated.Posterior arch nonunion was identified in 26 individuals (3.1% of 839 studies reviewed). Compared with age- and sex-matched controls, a 21% increase in area density product of the midline anterior arch was observed in posterior arch nonunion cases (773 HU-cm2 in cases vs. 637 HU-cm2 in controls; p.001). This increase was attributable to a 21% increase in cross-sectional area (1.05 cm2 in cases vs. 0.87 cm2 in controls; p.002). In contrast, there was no significant difference with regard to increased average radiodensity.It has long been subjectively recognized but not objectively quantified, until the present study, that the anterior arch of the atlas is hypertrophied in cases of posterior arch nonunion. Anterior arch hypertrophy may represent an adaptive response to chronically elevated mechanical stress and loss of hoop strength in cases of posterior nonunion.

The imaging evaluation of the rotator cuff augments the clinical evaluation. Radiography, computed tomography, and magnetic resonance imaging all have various roles in the assessment of the rotator cuff, which can be combined with arthrography for added detail. Furthermore, ultrasound is a very useful technique that provides functional information that is not offered by simple anatomic imaging.

Standard magnetic resonance imaging (MRI) as well as MR arthrography (MRA) have been important diagnostic tools to assess for a spectrum of clinical presentations related to the hip. MRA has allowed the radiologist to closely examine intracapsular structures such as the acetabular labrum. In this article, we provide a general review of soft tissue and osseous anatomy of hips, especially focusing on the MR appearances of the acetabular labrum and the osseous morphology of the greater trochanter and ischial tuberosity with their muscle and tendon attachments. In addition, current topics in recent literature will be discussed such as femoroacetabular impingement (FAI) and rotator cuff tears of the hip.