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Purpose To evaluate determinants of hip fracture by assessing soft-tissue composition of the upper thigh at CT. Materials and Methods In this retrospective analysis of prospectively collected data, CT studies in 55 female control participants (mean age, 73.1 years ± 9.3 [standard deviation]) were compared with those in 40 female patients (mean age, 80.2 years ± 11.0) with acute hip fractures. Eighty-seven descriptors of the soft-tissue composition were determined. A multivariable best subsets analysis was used to extract parameters best associated with hip fracture. Results were adjusted for age, height, and weight. Results of soft-tissue parameters were compared with bone mineral density (BMD) and cortical bone thickness. Areas under the receiver operating characteristic curve (AUCs) adjusted for multiple comparisons were determined to discriminate fracture. Results The hip fracture group was characterized by lower BMD, lower cortical thickness, lower relative adipose tissue volume of the upper thigh, and higher extramyocellular lipid (EML) surface density. The relative volume of adipose tissue combined with EML surface density (model S1) was associated with hip fracture (AUC, 0.85; 95% confidence interval [CI]: 0.78, 0.93), as well as trochanteric trabecular BMD combined with neck cortical thickness (model B2) (AUC, 0.84; 95% CI: 0.75, 0.92). The model including all four parameters provided significantly better (P < .01) discrimination (AUC, 0.92; 95% CI: 0.86, 0.97) than model S1 or B2. Conclusion In addition to bone mineral density and geometry of the proximal femur, the amount of adipose tissue of the upper thigh and the distribution of the adipocytes in the muscles are significantly associated with acute hip fracture at CT. © RSNA, 2018 Online supplemental material is available for this article.

Purpose To evaluate the performance of three imaging methods (radiography, dual-energy x-ray absorptiometry [DXA], and quantitative computed tomography [CT]) and that of a numerical analysis with finite element modeling (FEM) in the prediction of failure load of the proximal femur and to identify the best densitometric or geometric predictors of hip failure load. Materials and Methods Institutional review board approval was obtained. A total of 40 pairs of excised cadaver femurs (mean patient age at time of death, 82 years ± 12 [standard deviation]) were examined with (a) radiography to measure geometric parameters (lengths, angles, and cortical thicknesses), (b) DXA (reference standard) to determine areal bone mineral densities (BMDs), and (c) quantitative CT with dedicated three-dimensional analysis software to determine volumetric BMDs and geometric parameters (neck axis length, cortical thicknesses, volumes, and moments of inertia), and (d) quantitative CT-based FEM to calculate a numerical value of failure load. The 80 femurs were fractured via mechanical testing, with random assignment of one femur from each pair to the single-limb stance configuration (hereafter, stance configuration) and assignment of the paired femur to the sideways fall configuration (hereafter, side configuration). Descriptive statistics, univariate correlations, and stepwise regression models were obtained for each imaging method and for FEM to enable us to predict failure load in both configurations. Results Statistics reported are for stance and side configurations, respectively. For radiography, the strongest correlation with mechanical failure load was obtained by using a geometric parameter combined with a cortical thickness (r(2) = 0.66, P < .001; r(2) = 0.65, P < .001). For DXA, the strongest correlation with mechanical failure load was obtained by using total BMD (r(2) = 0.73, P < .001) and trochanteric BMD (r(2) = 0.80, P < .001). For quantitative CT, in both configurations, the best model combined volumetric BMD and a moment of inertia (r(2) = 0.78, P < .001; r(2) = 0.85, P < .001). FEM explained 87% (P < .001) and 83% (P < .001) of bone strength, respectively. By combining (a) radiography and DXA and (b) quantitative CT and DXA, correlations with mechanical failure load increased to 0.82 (P < .001) and 0.84 (P < .001), respectively, for radiography and DXA and to 0.80 (P < .001) and 0.86 (P < .001) , respectively, for quantitative CT and DXA. Conclusion Quantitative CT-based FEM was the best method with which to predict the experimental failure load; however, combining quantitative CT and DXA yielded a performance as good as that attained with FEM. The quantitative CT DXA combination may be easier to use in fracture prediction, provided standardized software is developed. These findings also highlight the major influence on femoral failure load, particularly in the trochanteric region, of a densitometric parameter combined with a geometric parameter. (©) RSNA, 2016 Online supplemental material is available for this article.

Purpose To determine the in vivo effects of several particulate steroids on microvascular perfusion by using intravital microscopy in a mice model and to investigate the in vitro interactions between these particulate steroids and red blood cells (RBCs). Materials and Methods The study was conducted in agreement with the guidelines of the National Committee of Ethic Reflection on Animal Experimentation. By using intravital microscopy of mouse cremaster muscle, the in vivo effects of several particulate steroids on microvascular perfusion were assessed. Four to five mice were allocated to each of the following treatment groups: saline solution, dexamethasone sodium phosphate, a nonparticulate steroid, and the particulate steroids cortivazol, methylprednisolone, triamcinolone, and prednisolone. By using in vitro blood microcinematography and electron microscopy, the interactions between these steroids and human RBCs were studied. All results were analyzed by using nonparametric tests. Results With prednisolone, methylprednisolone, or triamcinolone, blood flow was rapidly and completely stopped in all the arterioles and venules (median RBC velocity in first-order arterioles, 5 minutes after administration was zero for these three groups) compared with a limited effect in mice treated with saline, dexamethasone, and cortivazol (20.3, 21.3, and 27.5 mm/sec, respectively; P < .003). This effect was associated with a large decrease in the functional capillary density (4.21, 0, and 0 capillaries per millimeter for methylprednisolone, triamcinolone, or prednisolone, respectively, vs 21.0, 21.4, and 19.1 capillaries per millimeter in mice treated with saline, dexamethasone, and cortivazol, respectively; P < .003). This was because of the rapid formation of RBC aggregates. However, no change in microvascular perfusion was associated with administration of cortivazol or dexamethasone. In vitro experiments confirmed the formation of RBC aggregates associated with the transformation of RBCs into spiculated RBCs with the same steroids. Conclusion Several particulate steroids have an immediate and massive effect on microvascular perfusion because of formation of RBC aggregates associated with the transformation of RBCs into spiculated RBCs. (©) RSNA, 2016 Online supplemental material is available for this article.

Purpose: To assess the morphologic changes of osteoid osteomas on computed tomographic (CT) scans in association with pain duration., Materials and Methods: Institutional review board approval was obtained. Informed consent was waived. From January 2008 to December 2012, 235 patients were treated with interstitial laser ablation at the Hôpital Lariboisière. Ninety-six patients with histopathologically proven osteoid osteomas, complete clinical files, and CT data were studied retrospectively. The following variables were assessed: age, sex, bone location, bone segment, location of the osteoid osteoma in relation to the native cortex, nidus area, nidus calcification area and attenuation at CT, and nidus mineralization ratio (percentage of the calcification area over the total nidus area). Analysis of variance, Kaplan-Meier method, and Cox multivariate regression model were used for statistical analyses., Results: The study sample consisted of 96 patients, 68 of whom were male (71%) and 28 of whom were female (29%) (ratio of male to female patients, 2.4:1). Mean age ± standard deviation was 22.2 years ± 10.4 (range, 4-54 years; median, 18.5 years). The patients' age and nidus mineralization ratio increased significantly with pain duration (hazard ratio, 0.975 [P = .031] and 0.193 [P = .007], respectively). No significant association was found between pain duration and other variables, including the nidus area. In long bones, diaphyseal osteoid osteomas were significantly less mineralized than those in other locations (P = .009)., Conclusion: The nidus mineralization ratio of osteoid osteomas increases significantly with pain duration and may be a marker of tumor age. Diaphyseal osteoid osteomas demonstrate a lower ratio of nidus mineralization. At the onset of symptoms, older patients experience pain for a longer period before treatment.

Purpose: To evaluate the accuracy of ultrasonography (US) in determining the anatomic variations in the first extensor compartment of the wrist., Materials and Methods: Approval from the anatomic donations department was obtained. The first extensor compartment of the wrist of 40 nonembalmed cadaveric forearms (15 male and 25 female; age range at death, 65-100 years) were assessed at US by two observers for the presence or absence of a vertical septum, the presence or absence of an osseous ridge with a double groove in the bony floor, and whether there were single or multiple slips of the abductor pollicis longus and the extensor pollicis brevis tendons. These findings were also evaluated at dissection., Results: The accuracies of US in depicting a septum and an osseous ridge with a double groove were respectively 95% (95% confidence interval [CI]: 83%, 99%) and 100% (95% CI: 91%, 100%). At dissection, a septum was invariably associated with the presence of an osseous ridge. The accuracies of US in depicting multiple tendon slips of the abductor pollicis longus and the extensor pollicis brevis were respectively 80% (95% CI: 64%, 91%) and 97% (95% CI: 86%, 100%)., Conclusion: US was highly accurate in depicting anatomic variations in the first extensor compartment. US detection of an osseous ridge was an indirect sign of the presence of a septum dividing the first extensor compartment into two subcompartments., (© RSNA, 2010.)

Purpose: To use standard radiographs to determine which combination of co-occurrence textural parameters, geometric measurements, and cortical thickness measurements from femur radiographs provided the best estimate of femoral failure load and to compare these with total hip dual-energy x-ray absorptiometry bone mineral density (BMD) evaluation., Materials and Methods: Digital radiographs of 40 pairs of excised femurs (24 women, 16 men; mean age, 82 years + or - 12 [standard deviation]) were obtained. Regions of interest in the femoral neck, greater trochanter, intertrochanteric area, and femoral head were then selected. Three textural parameters derived from a co-occurrence matrix were estimated with imaging software. Neck-shaft angle, femoral neck axis length, calcar femorale thickness, and internal and external femoral shaft thickness were assessed. The femurs were randomly allocated to single-stance (femoral neck fracture) or side-impact (intertrochanteric fracture) configurations for failure load measurement., Results: Textural parameters correlated significantly with site-matched BMD. Stepwise regression analysis was performed, and total hip BMD explained 73% and 78% of the failure load in single-stance and side-impact configurations, respectively. Combining internal femoral shaft thickness with one or two textural parameters explained 72%-79% of failure load variance in the single-stance configuration and 63%-76% of failure load variance in the side-impact configuration., Conclusion: In these excised femurs, combining textural parameters with cortical thickness measurements had a performance comparable to that of BMD alone in the explanation of femoral failure load.

Purpose: To retrospectively evaluate the magnetic resonance (MR) imaging findings of vertebral involvement in patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome., Materials and Methods: Ethics committee approval and informed patient consent were not required for this retrospective study. MR images obtained in 12 patients (seven female, five male; mean age, 42 years; range, 16-65 years) with SAPHO syndrome involving the spine were reviewed. One vertebral lesion separated by one or more normal vertebrae was analyzed as a distinct lesion. For each lesion, the number of associated vertebrae with abnormal signal intensity (SI) (ie, single vertebra, two adjacent vertebrae, or more than two adjacent vertebrae) was noted. The following MR imaging findings were evaluated: cortical bone erosion, abnormal vertebral body SI compared with normal vertebral body SI, increased anteroposterior diameter of the vertebral body, soft-tissue involvement, vertebral body height loss of more than 30%, and abnormal SI of the adjacent intervertebral disk compared with the SI of the other disks., Results: Of 24 vertebral lesions found, 17 involved a single vertebra, four involved two adjacent vertebrae, and three involved three or four adjacent vertebrae. Vertebral corner cortical erosion was present in all lesions, and 23 (96%) lesions had anterior vertebral corner involvement. The erosion was confined to a vertebral corner in five (21%) lesions and included the adjacent endplate and/or the anterior cortex of the vertebral body in the remaining 19 (79%) lesions. In four (17%) lesions, involvement of two adjacent vertebral corners on either side of an intervertebral disk mimicked to some extent early disk space infection. An adjacent disk space was narrowed in six (25%) lesions and exhibited abnormal SI in two (8%). Prevertebral tissue thickening was observed in eight (33%) lesions., Conclusion: Erosion of a vertebral body corner is consistently seen on MR images of SAPHO vertebral lesions and may support the diagnosis of SAPHO syndrome in the appropriate clinical context.

Purpose: To assess spiral multidetector computed tomographic (CT) arthrography for the depiction of cartilage thickness in hips without cartilage loss, with evaluation of anatomic slices as the reference standard., Materials and Methods: Permission to perform imaging studies in cadaveric specimens of individuals who had willed their bodies to science was obtained from the institutional review board. Two independent observers measured the femoral and acetabular hyaline cartilage thickness of 12 radiographically normal cadaveric hips (from six women and five men; age range at death, 52-98 years; mean, 76.5 years) on spiral multidetector CT arthrographic reformations and on coronal anatomic slices. Regions of cartilage loss at gross or histologic examination were excluded. CT arthrographic and anatomic measurements in the coronal plane were compared by using Bland-Altman representation and a paired t test. Differences between mean cartilage thicknesses at the points of measurement were tested by means of analysis of variance. Interobserver and intraobserver reproducibilities were determined., Results: At CT arthrography, mean cartilage thickness ranged from 0.32 to 2.53 mm on the femoral head and from 0.95 to 3.13 mm on the acetabulum. Observers underestimated cartilage thickness in the coronal plane by 0.30 mm +/- 0.52 (mean +/- standard error) at CT arthrography (P < .001) compared with the anatomic reference standard. Ninety-five percent of the differences between CT arthrography and anatomic values ranged from -1.34 to 0.74 mm. The difference between mean cartilage thicknesses at the different measurement points was significant for coronal spiral multidetector CT arthrography and anatomic measurement of the femoral head and acetabulum and for sagittal and transverse CT arthrography of the femoral head (P < .001). Changes in cartilage thickness from the periphery to the center of the joint ("gradients") were found by means of spiral multidetector CT arthrography and anatomic measurement., Conclusion: Spiral multidetector CT arthrography depicts cartilage thickness gradients in radiographically normal cadaveric hips., ((c) RSNA, 2007.)

Purpose: To retrospectively review the bone findings at radiography, scintigraphy, computed tomography (CT), and magnetic resonance (MR) imaging in 11 patients with immunohistochemical and histologic proof of Erdheim-Chester disease., Materials and Methods: This study was designed as a retrospective review; approval of the institutional review board and patient consent were not required for this type of study. Eleven patients (eight men and three women; mean age, 49 years; range, 17-68 years) with Erdheim-Chester disease underwent conventional radiography of the skeleton and bone scintigraphy. Two patients underwent CT of the femora and 10 underwent CT of the skull. Eight patients underwent MR imaging. Conventional radiographs, bone scintigrams, CT scans, and MR images were reviewed in consensus by four musculoskeletal radiologists., Results: All 11 patients had involvement of the long bones and normal axial skeleton, hands, and feet. Bilateral and symmetric osteosclerosis of the diaphysis of the long bones was present in 52 (26 pairs) (98%) of the 53 bone lesions visible on conventional radiographs. Osteosclerosis was heterogeneous in 65% of the patients and homogeneous in 35%. Diaphysis was involved in 100% and metaphysis in 44 (83%) lesions. Partial epiphyseal involvement sparing the subchondral bone was present in 24 (45%) lesions. Periostitis was seen in 35 (66%) and endosteitis in 50 (94%) of the 53 long bones involved. Bone scintigraphy depicted tracer uptake in all bone lesions visible on radiographs. Skull and face bone lesions were present in two patients. MR imaging depicted a replacement of the normal fatty bone marrow by heterogeneous signal intensity on T1- and T2-weighted spin-echo images. Lesion extent, epiphyseal involvement, and periostitis were clearly depicted at MR imaging., Conclusion: This series provides a detailed description of bone involvement in Erdheim-Chester disease. Periostitis and partial epiphyseal involvement of the long bones are also features of this disease. (c) RSNA, 2005., ((c) RSNA, 2005)

Purpose: To report complications of direct fibrosing agent injection in the treatment of aneurysmal bone cysts (ABCs) in children., Materials and Methods: The authors retrospectively analyzed all cases of ABCs treated with direct fibrosing agent injection (Ethibloc; Ethnor Laboratories, Ethicon, Noderstedt, Germany) at Robert Debré Hospital since 1994. Histologic diagnosis was assigned by means of surgical biopsy findings prior to treatment. Treatment responses were categorized. Injection was administered with general anesthesia, computed tomographic guidance, and use of a 14- to 16-gauge needle. Contrast material was injected to determine presence of intracystic septa and verify absence of venous opacification. Amount of fibrosing agent injected corresponded to amount of contrast material necessary to fully opacify the cyst. Intraosseous needle track was obliterated with histoacryl injection., Results: Fifteen patients were treated. Mean follow-up was 80 months; no patient was lost to follow-up. One patient experienced pulmonary embolus that necessitated a 7-day intensive care unit stay. Four patients experienced early aseptic fistulization after the first injection, which led to surgical débridement and curettage. Five patients had transient inflammatory reaction with mild 38 degrees C fever, which was controlled with analgesic and antiinflammatory drugs. Eleven patients did not require surgery, and results at latest follow-up were considered to indicate complete healing (type 1 results) in nine and incomplete healing (type 2 results) in two. For type 1 results: Six patients received one injection, two received two injections, and one received three injections. For type 2 results: one patient received one injection, and one received three injections., Conclusion: A high rate of major local and general complications was encountered with use of direct fibrosing agent injection; the technique has been abandoned for treatment of ABCs., (Copyright RSNA, 2004)

Purpose: To determine whether computed tomography (CT) can be used to quantify age- and site-related changes in cortical bone mineral density (cBMD) at the middiaphyseal femur and whether cBMD differences are related to intracortical porosity., Materials and Methods: Cortical bone specimens from 163 femurs were studied with CT and microradiography. Femurs were from 77 males and 86 females in a white anthropologic collection covering a broad age spectrum. In each sample, the cBMD was measured in the entire cortical width and in periosteal, midcortical, and endosteal subregions of interest. Age- and site-related changes in cBMD were tested for significance by using a two-way analysis of variance for both sexes. By using linear regression, cBMD was compared with porosity in the entire cortical width and in each subregion., Results: There were significant age-related differences in cBMD (P <.001 in females, P =.008 in males). In addition, cBMD values were significantly different between the three cortical subregions (P <.001 for both sexes), decreasing from the periosteum to the midcortex to the endosteum. The cBMD values were closely related to porosity, and porosity contributed to 71.6% of the variance in cBMD in the overall population., Conclusion: CT is effective in the measurement of age- and site-related changes in cBMD. Decreases in cBMD are closely correlated with increased cortical porosity.

Purpose: To study the results of facet joint intraarticular steroid injections in patients with symptomatic lumbar facet joint synovial cysts., Materials and Methods: Data from 30 patients (age range, 44-82 years; mean age, 67 years) with nerve root pain due to a lumbar facet joint synovial cyst and treated with facet joint steroid injection were retrospectively studied. On the basis of MacNab criteria, the clinical course of nerve root pain was evaluated after 1 (n = 30) and 6 (n = 28) months. Data from long-term follow-up (mean, 26 months) were also available in 14 nonsurgically treated patients., Results: After 1 month, the nerve root pain outcome was excellent or good in 20 patients (67%) and fair or poor in 10 (33%). After 6 months, 10 (50%) of these 20 patients still had excellent or good results, and 18 (60%) of the 30 patients had a fair or poor clinical status, 14 of whom underwent surgery; two patients (7%) were lost to follow-up. Excellent and good results were maintained at further follow-up (range, 9-50 months)., Conclusion: One-third of patients with symptomatic lumbar facet joint synovial cysts had long-lasting acceptable benefit from facet joint steroid injections in this study. Steroid injection should be indicated before surgery.

Purpose: To distinguish malignant from osteoporotic acute vertebral collapses., Materials and Methods: Sixty-three osteoporotic and 30 malignant vertebral collapses were studied in 51 patients (aged 33-88 years) with T1-weighted magnetic resonance (MR) images (n=93), gadolinium-enhanced T1-weighted images (n=72), and T2-weighted images (n=53)., Results: Four findings were suggestive of osteoporosis: retropulsion of a bone fragment (10 osteoporotic cases vs 0 malignant cases), preservation of normal signal intensity on T1-weighted images (43 vs four), return to normal signal intensity after gadolinium injection (42 vs four) with horizontal bandlike patterns, and isointense vertebrae on T2-weighted images (28 vs two). Six findings were suggestive of malignancy: convex posterior cortex (21 malignant cases vs four osteoporotic cases), epidural mass (24 vs 0), diffuse low signal intensity within the vertebral body on T1-weighted images (23 vs 12) and in the pedicles (24 vs four), high or inhomogeneous signal intensity after gadolinium injection (17 vs 0) and on T2-weighted images (17 vs 0)., Conclusion: Gadolinium-enhanced and unenhanced MR images are useful in the differentiation of vertebral collapses.

Purpose: The value of computed tomography (CT) for differentiating benign from malignant causes of nontraumatic acute vertebral collapse (AVC) (associated with pain of less than 3 months duration) was evaluated., Materials and Methods: The CT findings of 34 benign (osteoporotic) and 32 malignant (metastatic or myelomatous) nontraumatic AVCs were compared., Results: The following CT findings were significantly more frequent in benign AVCs: cortical fractures of the vertebral body without cortical bone destruction, retropulsion of a bone fragment of the posterior cortex of the vertebral body into the spinal canal, fracture lines within the cancellous bone of the vertebral body, an intravertebral vacuum phenomenon, and a thin diffuse paraspinal soft-tissue mass (PSTM). The following CT findings were significantly more frequent in malignant AVCs: destruction of the anterolateral or posterior cortical bone of the vertebral body, destruction of the cancellous bone of the vertebral body, destruction of a vertebral pedicle, a focal PSTM, and an epidural mass., Conclusion: CT can help distinguish benign from malignant causes of nontraumatic AVC.

Thirty-two vertebral hemangiomas (VHs) were evaluated with nonenhanced computed tomography (CT), T1-weighted magnetic resonance (MR) imaging, CT enhanced with contrast material, and selective spinal arteriography. The stroma between the osseous trabeculae was found to correspond to either fatty tissue or soft tissue or both. All 11 asymptomatic VHs showed complete fatty stroma at CT and increased signal intensity at MR imaging. In contrast, all four compressive VHs had soft-tissue attenuation at CT. Three compressive VHs showed low signal intensity on MR images. Predominantly fatty stroma at CT and increased signal intensity at MR imaging were associated with normal or only slightly increased vascularization at selective spinal arteriography or contrast-enhanced CT, while soft-tissue stroma at CT and low signal intensity at MR imaging were associated with distinct hypervascularization. The authors' experience suggests that fatty VHs may represent inactive forms of VH, while soft-tissue content at CT and low signal intensity at MR imaging may indicate a more active vascular lesion with potential to compress the spinal cord. CT and MR imaging may be especially valuable for evaluating patients with clinical signs or symptoms of uncertain origin and findings compatible with VH at plain radiography.

Radiologic studies of 57 solitary vertebral hemangiomas (VHs) were reviewed to find radiographic and computed tomographic (CT) criteria by which to distinguish asymptomatic lesions from those compressing the spinal cord. Six features were seen significantly more often in those compressing the cord: location between T-3 and T-9, involvement of the entire vertebral body, extension to the neural arch, an expanded cortex with indistinct margins, an irregular honeycomb pattern, and soft-tissue mass. Contrast material-enhanced CT scans and selective spinal angiograms demonstrated extension into the spinal canal. In patients with a VH and back pain of uncertain origin, the presence of three or more of these signs may indicate a potentially symptomatic VH. In such patients, spinal angiography and, in some cases, embolization, are indicated.