Collapse-Related Bone Changes in Osteonecrotic Femoral Heads at Multidetector CT: Comparison between Femoral Heads with Limited and Advanced Collapse.

Aim: To assess the frequency of bone changes in resected osteonecrotic femoral head (ONFH) specimens at multidetector computed tomography (MDCT) and compare their frequencies between ONFH with limited or advanced collapse. Method: Fourteen ONFH were imaged using MDCT (n = 14) and microcomputed tomography ([µCT]; n = 8). Preoperative staging was performed using radiographs and MRI. Coronal reformats of MDCT images of the specimens were analyzed using the grid overlay method. There were 2,933 grid boxes containing cortical bone and 10,596 containing trabecular bone. Two MSK radiologists assessed in every grid box the presence of interface-related sclerosis, cortical bone interruption, trabecular bone interruption, and trabecular bone resorption. The frequency of grid boxes with bone changes at MDCT was calculated and compared between ONFH with limited (<1.5 mm) or advanced (≥1.5 mm) collapse. Results: For both readers R1 and R2, there were 1111/10596 (10.5%) and 1362/10596 (12.9%) grid boxes with interface-related bone sclerosis, 557/2933 (19%) and 413/2933 (14.1%) with cortical bone interruption, 796/10596 (7.5%) and 665/10596 (6.3%) with trabecular bone interruption, and 331/10596 (3.1%) and 595/10596 (5.6%) with trabecular bone resorption. The frequency of grid boxes with cortical interruption and trabecular bone resorption was significantly higher in ONFH with advanced than in ONFH with limited collapse. There was no significant difference in frequency of grid boxes with trabecular interruption and interface-related bone sclerosis between ONFH with advanced or limited collapse. Conclusion: Cortical interruption and trabecular resorption, but not trabecular interruption, were more frequent in osteonecrotic femoral heads with advanced than with limited collapse.

Imaging of treatment response and minimal residual disease in multiple myeloma: state of the art WB-MRI and PET/CT.

Bone imaging has been intimately associated with the diagnosis and staging of multiple myeloma (MM) for more than 5 decades, as the presence of bone lesions indicates advanced disease and dictates treatment initiation. The methods used have been evolving, and the historical radiographic skeletal survey has been replaced by whole body CT, whole body MRI (WB-MRI) and [18F]FDG-PET/CT for the detection of bone marrow lesions and less frequent extramedullary plasmacytomas.Beyond diagnosis, imaging methods are expected to provide the clinician with evaluation of the response to treatment. Imaging techniques are consistently challenged as treatments become more and more efficient, inducing profound response, with more subtle residual disease. WB-MRI and FDG-PET/CT are the methods of choice to address these challenges, being able to assess disease progression or response and to detect "minimal" residual disease, providing key prognostic information and guiding necessary change of treatment.This paper provides an up-to-date overview of the WB-MRI and PET/CT techniques, their observations in responsive and progressive disease and their role and limitations in capturing minimal residual disease. It reviews trials assessing these techniques for response evaluation, points out the limited comparisons between both methods and highlights their complementarity with most recent molecular methods (next-generation flow cytometry, next-generation sequencing) to detect minimal residual disease. It underlines the important role of PET/MRI technology as a research tool to compare the effectiveness and complementarity of both methods to address the key clinical questions.

Giant intraosseous ganglion of the fibula: multimodality imaging.

Intraosseous ganglia around the knee are most commonly located in the proximal tibia and limited to the epiphyseal-metaphyseal region. We report the case of a giant intraosseous ganglion of the fibula. MRI demonstrated the fluid avascular content of the lesion. CT arthrography of the knee demonstrated partial opacification of the lesion through a cortical bone defect. The lesion was treated with curettage and bone grafting. Anatomopathological examination confirmed the medical imaging diagnosis of intraosseous ganglion. This case highlights the value of joint opacification with CT arthrography to demonstrate the communication between the articular cavity and the ganglion.

Osteoid osteoma of the hip: imaging features.

Osteoid osteoma (OO), a small bone tumor relatively common in young subjects, frequently involves the hip. In addition to typical findings, we emphasize unsuspected clinical and imaging features including painless OO causing limping gait, non-visibility of totally mineralized nidus, absence of hyperostosis or adjacent edema, and recurrence at distance from the initial location. We also discuss the option of medical treatment for some cases of deep hip locations.

Two-point Dixon fat-water swapping artifact: lesion mimicker at musculoskeletal T2-weighted MRI.

Fat-water swapping is an artifact specific to chemical shift encoded MRI and so-called Dixon methods. It is more frequent using the 2-point than the multi-point (> 2) Dixon method. Actually, fat-water swapping on the 2-point Dixon sequences partly triggered the development of the multi-point techniques. Fat-water swapping occurs on post-processing calculated fat- and water-only images, but not on the directly acquired in-phase and out-of-phase source images. It originates from a natural ambiguity between fat and water peaks that may cause inverted calculation between fat- and water-only voxels. Fat-water swapping artifact over large areas encompassing multiple tissues can easily be recognized, but it may be confusing when the calculation errors are limited to a single anatomic structure or a small area, especially on T2-weighted images. We report four cases with 2-point Dixon fat-water swapping artifacts mimicking musculoskeletal lesions at T2-weighted MRI and propose hints to avoid misinterpretation.

Fasciae of the musculoskeletal system: MRI findings in trauma, infection and neoplastic diseases.

The fascial system is a continuum of connective tissues present everywhere throughout the body that can be locally involved in a large variety of disorders. These disorders include traumatic disorders (Morel-Lavallée lesion, myo-aponeurotic injuries, and muscle hernia), septic diseases (necrotizing and non-necrotizing cellulitis and fasciitis), and neoplastic diseases (superficial fibromatosis, desmoid tumors, and sarcomas). The current pictorial review aims to focus on these localized disorders involving the fasciae of the musculoskeletal system and their appearance at MRI.

Diagnostic Accuracy of Echo Envelope Statistical Modeling Compared to B-Mode and Power Doppler Ultrasound Imaging in Patients With Clinically Diagnosed Lateral Epicondylosis of the Elbow.

OBJECTIVES: To compare the accuracy of homodyned K quantitative ultrasound (QUS) with that of B-mode and Doppler ultrasound imaging for discriminating between lateral epicondylosis (LE) and asymptomatic elbows. METHODS: This prospective study received Institutional Review Board approval, and participants provided written informed consent. Between February 2015 and March 2017, 30 LE elbows in 27 patients and 24 asymptomatic elbows in 13 volunteers underwent B-mode, Doppler, and radiofrequency ultrasound imaging of the common extensor tendon (CET) and radial collateral ligament (RCL). Two readers classified the elbows independently on the basis of a review of B-mode and Doppler images. The global and local estimates of QUS parameters (µ n , 1/α, and k) were computed in the CET and CET-RCL regions, respectively, and the area of each region was calculated. A random-forest classifier identified the most discriminating 3-parameter combination: CET global estimate of 1/α, CET-RCL area, and local estimate of k. RESULTS: The patients with LE had a mean age of 50 years (range, 31-66 years), and the volunteers had a mean age of 50 years (range, 37-57 years). The area under the receiver operating characteristic curve, sensitivity, and specificity of reader 1, reader 2, and the QUS-based model were 0.80 (95% confidence interval [CI], 0.66-0.95), 0.72 (95% CI, 0.56-0.89), and 0.88 (95% CI, 0.72-1.04); 0.79 (95% CI, 0.66-0.93), 0.65 (95% CI, 0.47-0.82), and 0.84 (95% CI, 0.67-1.01); and 0.82 (95% CI, 0.80-0.85), 0.73, and 0.79, respectively. CONCLUSIONS: An automated, computer-based QUS technique diagnosed LE with accuracy of 0.82. This technique could provide quantitative biomarkers for the characterization of LE disease.

Femoral osteochondroma responsible for ischiofemoral impingement, bursitis, and secondary lipoma arborescens mimicking malignant transformation.

We present the case of a 53-year-old woman with a known history of hereditary multiple exostosis disease referred for further imaging work-up after ultrasound and computed tomography leading to the suspicion of malignant transformation of an osteochondroma (exostosis) located on the posteromedial aspect of the right proximal femur. Imaging examinations suggested an ischiofemoral impingement resulting in a secondary bursitis associated with the development of an internal lipoma arborescens. This rare association explained the complexity of the diagnosis. Magnetic resonance imaging (MRI) played a key role in correctly identifying this benign complication of the osteochondroma and in distinguishing those observations from a secondary exostotic chondrosarcoma. MRI findings were subsequently confirmed at surgery and pathological examination.

Unusual proximal fragment migration of an os peroneum fracture with associated peroneus longus tendon injury-a tree often hides a forest.

We report the case of a 55-year-old male patient who presented to the emergency department after sustaining a right ankle trauma. Swelling and tenderness of the lateral aspect of the right ankle were present on physical examination without evidence of motor or sensory deficit. Ankle radiographs were performed and showed two bony fragments, the first located postero-inferiorly to the cuboid bone while the second was adjacent to the tip of the lateral malleolus. The diagnosis of an os peroneum fracture was made with high suspicion of an associated peroneus longus tendon rupture. Computed tomography (CT) and magnetic resonance imaging (MRI) of the right ankle confirmed the diagnosis of a subtotal retracted tendinous rupture. Successful surgical repair of the injured tendon was performed. This article illustrates the imaging findings of an os peroneum fracture with its associated tendinous injury and reviews the literature.

Fasciae of the musculoskeletal system: normal anatomy and MR patterns of involvement in autoimmune diseases.

The fascial system is a three-dimensional continuum of connective tissues present everywhere throughout the body, from the head to the toes and from the skin to the bone. The current article aims to review the normal anatomy of the fasciae of the musculoskeletal system with macroscopic and microscopic correlations and to describe their appearance at MRI in normal subjects and in patients with autoimmune diseases of the musculoskeletal system. KEY POINTS: • The fascial system is a three-dimensional continuum of connective tissues. • It is present everywhere throughout the body, from the head to the toes and from the skin to the bone. • The normal fascial system is barely visible at MRI. • MR patterns of fascial involvement in autoimmune diseases reflect the complex anatomy of the fasciae of the musculoskeletal system.

Uncommon observation of bifocal giant subchondral cysts in the hip: diagnostic role of CT arthrography and MRI, with pathological correlation.

Subchondral cysts (or geodes) are common in osteoarthritis (OA), usually in association with other typical signs, i.e., joint space narrowing, subchondral bone sclerosis, and osteophytosis. However, large lesions without the typical signs of OA or lesions located outside the weight-bearing areas are unusual and may be confused for other conditions, in particular, those of tumoral origin. We report the findings in a 48-year-old man who had been complaining of left buttock pain for 3 years, getting worse over the last year, and an evolutive limited range of motion of the hip. The pain was increased by weight-bearing and was not relieved by nonsteroidal anti-inflammatory drugs. Radiographs and CT showed a large multilocular lytic lesion within the femoral head and a large lytic lesion in the left ilio-ischiatic ramus, raising the question of bifocal tumoral involvement. On MRI, the lesions had low signal intensity on T1- and high signal intensity on T2-weighted MR images, with subtle peripheral enhancement on post-contrast T1-weighted images. CT arthrography, by demonstrating a communication between the femoral head and ischiatic cysts and the joint space allowed us to definitively rule out malignant conditions and to make the diagnosis of subchondral bone cysts. Total hip arthroplasty was performed. Pathological analysis of the resected femoral head and of material obtained at curettage of the ischiatic lesion confirmed the diagnosis of degenerative geodes. This case illustrates an atypical bifocal location of giant subchondral cysts in the hip joint mimicking lytic tumors, in the absence of osteoarthritis or rheumatoid arthritis, and highlights the role of CT arthrography in identifying this condition.

Anterior shoulder instability: the role of advanced shoulder imaging in preoperative planning.

Despite advances in the understanding of anterior shoulder instability, recurrence rates after arthroscopic and open surgery have been reported to be as high as 30%. A successful operative outcome for patients with anterior shoulder instability requires the surgeon to perform a complete preoperative evaluation based on a thorough physical examination and advanced imaging techniques. In addition to the Bankart lesion, the treating surgeon must be aware of other copathologies, such as bony lesions of the glenoid or humeral head, humeral avulsion of the glenohumeral ligament, and articular cartilage defects that can occur in concert with capsular pathology and may necessitate a change in surgical strategy. This article focuses specifically on the osseous, labroligamentous, cartilage, and rotator cuff lesions demonstrated on preoperative imaging that are important to recognize in the preoperative work-up to optimize surgical outcomes for anterior instability.

Radiographical texture analysis improves the prediction of vertebral fracture: an ex vivo biomechanical study.

STUDY DESIGN: Compression biomechanical tests using fresh cadaveric thoracolumbar motion segments. OBJECTIVE: The purpose of this study was to determine if the combination of bone texture parameters using bone microarchitecture, and bone mineral density (BMD) measurement by dual-energy x-ray absorptiometry provided a better prediction of vertebral fracture than BMD evaluation alone. SUMMARY OF BACKGROUND DATA: Bone strength is routinely evaluated using BMD, as measured by dual-energy x-ray absorptiometry. Currently, there is an ongoing debate about the strengths and limitations of bone densitometry in clinical practice. To assess the fracture risk properly, other factors are important to be taken into account such as the macro- and microarchitecture of the bone. Recently, a new high-resolution x-ray device with direct digitization, named bone microarchitecture (BMA, D3A Medical Systems), has been developed to provide a better precision of texture parameters than those previously obtained on digitized films. METHODS: Twenty-seven 3-level thoracolumbar motion segments (T11, T12, L1, and L2, L3, L4) of excised spines, obtained at the Anatomy Department of Marseille, were studied using bone microarchitecture to estimate 3 textural parameters: fractal parameter Hmean, co-occurrence matrix, and run-length matrix, dual-energy x-ray absorptiometry to measure BMD, and mechanical compression tests to failure. All specimens were examined by computed tomography before and after compression. The prediction of the vertebral failure load was evaluated using multiple regression analyses. RESULTS: Twenty-seven vertebral fractures were observed with a mean failure load of 2636.3 N (standard deviation, 996 N). Fractal parameter Hmean, co-occurrence matrix, and run-length matrix were each significantly correlated with BMD (P< 0.01) and bone strength (P< 0.01). Combining bone texture parameters and BMD significantly improved the fracture load prediction from adjusted r = 0.701 to adjusted r = 0.806 (P< 0.01). CONCLUSION: In these excised vertebrae, the combination of bone texture parameters with BMD demonstrated a better performance in the failure load prediction than that of BMD alone. LEVEL OF EVIDENCE: N/A.

Preoperative imaging of anterior shoulder instability: diagnostic effectiveness of MDCT arthrography and comparison with MR arthrography and arthroscopy.

OBJECTIVE: The purpose of this article is to assess the diagnostic effectiveness of MDCT arthrography in the preoperative planning of anterior shoulder instability compared with MR arthrography and arthroscopy. SUBJECTS AND METHODS: Shoulder MDCT arthrography and MR arthrography examinations prospectively performed in 40 consecutive patients (30 male and 10 female patients; mean age, 26 years) were independently evaluated by two musculoskeletal radiologists who were blinded to the arthroscopic findings, which represented the reference standard. Sensitivity, specificity, and agreement with arthroscopy were determined for osseous, cartilage, and labroligamentous injuries. RESULTS: In detecting glenoid rim fractures, MDCT arthrography had a sensitivity of 100% (12/12), a specificity of 96% (27/28), and better agreement with surgery (κ = 0.94) than did MR arthrography (κ = 0.74). For the depiction of glenoid cartilage lesions, MDCT arthrography had a sensitivity of 82% (18/22), a specificity of 89% (16/18), and slightly better agreement with surgery (κ = 0.70) than did MR arthrography (κ = 0.66). In identifying anterior labral periosteal sleeve avulsion lesions, MDCT arthrography had a sensitivity of 93% (26/28), a specificity of 100% (12/12), and better agreement with surgery (κ = 0.89) than did MR arthrography (κ = 0.74). For the diagnosis of humeral avulsion of the inferior glenohumeral ligament lesions, MDCT arthrography had a sensitivity and a specificity of 100% (2/2) and better agreement with surgery (κ = 1) than did MR arthrography (κ = 0.79). CONCLUSION: MDCT arthrography showed better accuracy than did MR arthrography in the detection of osseous, cartilage, and labroligamentous injuries related to anterior shoulder instability. Because MDCT arthrography was particularly reliable for the detection of glenoid rim fractures and humeral avulsion of the inferior glenohumeral ligament lesions, which represent crucial findings in the preoperative planning, this technique may beneficially affect treatment by means of selecting the proper surgical treatment.

Congenital anomalies of inferior vena cava in young patients with iliac deep venous thrombosis.

Venous thromboembolism (VTE) in young patients is frequently associated with hereditary biological thrombophilia, autoimmune disorders, or neoplasia. Advances in venous ultrasound and contrast-enhanced computed tomography have allowed for the identification of inferior vena cava (IVC) anomalies as newly considered etiologic factor. We present two cases of VTE in young patients: the first case involves left IVC in a 22-year-old man and the second involves IVC atresia in a 39-year-old man. IVC anomalies should be identified in young patients with spontaneous VTE involving the iliac veins because they are at a high risk for thrombotic recurrence and adaptation to long periods of antithrombotic therapy.