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In this case report, we describe an "uncommon" case of axial gouty arthropathy in a 69-year-old woman with bilateral sciatica that was thoroughly evaluated with conventional radiography, CT scan, magnetic resonance imaging, bone scintigraphy, and PET-CT. Axial gouty arthropathy should be included in the differential diagnosis of chronic low back pain, mainly when several risk factors for gout are present.

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Necrotizing fasciitis is a rare, rapidly spreading, deep-seated infection causing thrombosis of the blood vessels located in the fascia. Necrotizing fasciitis is a surgical emergency. The diagnosis typically relies on clinical findings of severe sepsis and intense pain, although subacute forms may be difficult to recognize. Imaging studies can help to differentiate necrotizing fasciitis from infections located more superficially (dermohypodermitis). The presence of gas within the necrotized fasciae is characteristic but may be lacking. The main finding is thickening of the deep fasciae due to fluid accumulation and reactive hyperemia, which can be visualized using computed tomography and, above all, magnetic resonance imaging (high signal on contrast-enhanced T1 images and T2 images, best seen with fat saturation). These findings lack specificity, as they can be seen in non-necrotizing fasciitis and even in non-inflammatory conditions. Signs that support a diagnosis of necrotizing fasciitis include extensive involvement of the deep intermuscular fascias (high sensitivity but low specificity), thickening to more than 3mm, and partial or complete absence on post-gadolinium images of signal enhancement of the thickened fasciae (fairly high sensitivity and specificity). Ultrasonography is not recommended in adults, as the infiltration of the hypodermis blocks ultrasound transmission. Thus, imaging studies in patients with necrotizing fasciitis may be challenging to interpret. Although imaging may help to confirm deep tissue involvement and to evaluate lesion spread, it should never delay emergency surgical treatment in patients with established necrotizing fasciitis.

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Multi-detector CT imaging (MDCT) becomes routine imaging modality in the assessment of the postoperative orthopedic patients with metallic instrumentation that degrades image quality at MR imaging. This article reviews the physical basis and CT appearance of such metal-related artifacts. It also addresses the clinical value of MDCT in postoperative orthopedic patients with emphasis on fracture healing, spinal fusion or arthrodesis, and joint replacement. MDCT imaging shows limitations in the assessment of the bone marrow cavity and of the soft tissues for which MR imaging remains the imaging modality of choice despite metal-related anatomic distortions and signal alteration.

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This article focuses on spontaneous painful conditions involving the subchondral bone and marrow of mature knee epiphyses. MR imaging is the technique of choice for the work-up of these lesions and enables distinction of two main categories of lesions on the basis of T1-weighted images: avascular necrosis, and lesions presenting the bone marrow edema pattern. This latter category encompasses spontaneous osteonecrosis of the knee, and a variety of self-resolving conditions that may be differentiated by the study of the subchondral bone marrow area on T2-weighted images. Behind definite appellation of lesions, the challenge for the radiologist is to provide a prognosis: the distinction between self-resolving lesions from those that may evolve to epiphyseal collapse and joint impairment should be possible in most cases.

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MR imaging of the spine is routinely performed for the assessment of patients with spine-related symptoms and of patients with cancer. This article addresses normal variants and frequent alterations of the vertebral bone marrow that are encountered on MR imaging studies and can simulate lesions.

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This study aimed to assess the feasibility of cardiac global function evaluation during a whole-chest multi-slice CT (MSCT) acquisition in patients referred for suspicion of pulmonary embolism (PE), and to compare the results with planar equilibrium radionuclide ventriculography (ERNA). Ten consecutive haemodynamically stable patients (six female, four male; mean age 69.7 years; heart rate 65-99 bpm) with suspicion of PE underwent an MSCT and ERNA within a 6 h period. CT acquisition was performed after contrast medium injection by using 16x1.5 mm collimation and retrospective ECG gating. Left ventricular (LVEF) and right ventricular (RVEF) ejection fractions were calculated using dedicated three-dimensional software. Relationships between measurements obtained with MSCT and ERNA were assessed using linear regression analysis and reliability of MSCT was assessed with intra-class correlation coefficient. Bland-Altman analysis was performed to calculate limits of agreement between MSCT and ERNA. MSCT was performed successfully in ten patients with a mean acquisition time of 16.5+/-2.8 s. Functional cardiac evaluation was possible on CT for all patients except for one due to poor opacification of right ventricle. Linear regression analysis showed a good correlation between MSCT and ERNA for the LVEF (R=0.91) and the RVEF (R=0.89) measurements. Intra-class correlation was superior for LVEF (0.92) than for the RVEF (0.68). Bland-Altman plots demonstrated that MSCT substantially overestimated the ERNA RVEF. Morphological CT data demonstrated PE in four of ten of patients and alternative diagnoses in five of ten patients. Our study reveals that MSCT with retrospective ECG gating may provide in one modality a morphological and a functional cardiopulmonary evaluation. Comparison with ERNA demonstrated a good correlation for both ventricular ejection fractions.

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PURPOSE: To retrospectively evaluate magnetic resonance (MR) imaging for the depiction of meniscal tears with partially detached meniscal fragments displaced in the intercondylar notch or in the meniscal recesses of the knee. MATERIALS AND METHODS: The institutional review board required neither its approval nor informed patient consent for the retrospective review of patient data; however, informed patient consent had been obtained before the MR imaging examinations were performed. The presence of meniscal tears with notch and recess fragments was determined at MR imaging and at subsequent arthroscopy in 101 consecutive knees to determine the value of MR imaging for the depiction of these lesions. Initial reports were reviewed to evaluate results of initial interpretations. MR images were retrospectively analyzed to determine the value of several MR image signs for the detection of displaced tears with notch or recess fragments. RESULTS: At arthroscopy, 37 (41%) of 91 torn menisci had partially detached fragments. Twenty-six torn menisci had notch fragments, and 14 had recess fragments; three torn menisci had one notch and one recess fragment each. At initial MR image analysis, 38 (36%) of 105 torn menisci had partially detached fragments. Twenty-eight torn menisci had notch fragments, and 13 had recess fragments; one torn meniscus had two recess fragments, and three torn menisci had one notch and one recess fragment each. At initial analysis, sensitivities and specificities were, respectively, 69% and 94% for detection of tears with notch fragments and 71% and 98% for detection of tears with recess fragments. At retrospective analysis of sagittal MR images, the presence of at least one sign indicative of meniscal tear with a notch fragment had sensitivities and specificities, respectively, of 65% and 78% for observer 1 and 77% and 73% for observer 2. The presence of at least one sign indicative of a meniscal tear with a recess fragment had sensitivities and specificities, respectively, of 64% and 77% for observer 1 and 64% and 76% for observer 2. CONCLUSION: Meniscal tears with notch and recess fragments are frequently seen at arthroscopy and can be depicted at knee MR imaging with moderate sensitivity and high specificity.

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OBJECTIVE: To explain a cause of high signal intensity on T1-weighted MR images in calcified intervertebral disks associated with spinal fusion. DESIGN AND PATIENTS: Magnetic resonance and radiological examinations of 13 patients were reviewed, presenting one or several intervertebral disks showing a high signal intensity on T1-weighted MR images, associated both with the presence of calcifications in the disks and with peripheral fusion of the corresponding spinal segments. Fusion was due to ligament ossifications (n=8), ankylosing spondylitis (n=4), or posterior arthrodesis (n=1). Imaging files included X-rays and T1-weighted MR images in all cases, T2-weighted MR images in 12 cases, MR images with fat signal suppression in 7 cases, and a CT scan in 1 case. Histological study of a calcified disk from an anatomical specimen of an ankylosed lumbar spine resulting from ankylosing spondylitis was examined. RESULTS: The signal intensity of the disks was similar to that of the bone marrow or of perivertebral fat both on T1-weighted MR images and on all sequences, including those with fat signal suppression. In one of these disks, a strongly negative absorption coefficient was focally measured by CT scan, suggesting a fatty content. The histological examination of the ankylosed calcified disk revealed the presence of well-differentiated bone tissue and fatty marrow within the disk. CONCLUSION: The high signal intensity of some calcified intervertebral disks on T1-weighted MR images can result from the presence of fatty marrow, probably related to a disk ossification process in ankylosed spines.

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Elastofibroma dorsi is a tumor or pseudotumor typically located under the tip of the scapula. It is far from uncommon in older individuals. The mass contains both fibrous tissue and fatty tissue. Imaging studies can provide the definite diagnosis in many cases. Computed tomography (CT) and magnetic resonance imaging (MRI) are particularly effective, as they visualize the characteristic layered pattern of fatty tissue (low-density by CT, high-signal on T1 images and intermediate signal on T2 images by MRI) and fibrous tissue (similar to muscle in terms of density by CT and signal intensity by MRI). To a lesser extent, plain radiographs and ultrasonography identify a number of suggestive features (location and layered structure). When the lesion exhibits typical imaging features and produces no symptoms, as is usually the case, further investigations are probably unnecessary.

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PURPOSE: To assess the effectiveness of dual-detector row spiral computed tomographic (CT) arthrography of the knee in the evaluation of the postoperative meniscus for recurrent or residual meniscal tear. MATERIALS AND METHODS: Spiral CT arthrography was performed in 20 patients who presented with pain after partial meniscectomy. Findings at the initial reading of the images and at two retrospective independent readings were compared with those at second-look arthroscopy performed in all patients. At initial interpretation, conventional criteria for meniscal tear were used, including partial- or full-thickness tear of any size and meniscal separation. At retrospective interpretation, criteria for meniscal tear included large partial- and full-thickness tear and meniscal separation but not small partial-thickness tear. Sensitivity and specificity for the detection of tear of the postoperative menisci were calculated for initial and retrospective readings. RESULTS: At initial interpretation, the sensitivity and specificity for the detection of tear of the postoperative menisci were 100% and 78%, respectively. At retrospective interpretation, the sensitivity and specificity for the detection of tear of the postoperative menisci were 79% and 89% at reading 1 and 93% and 89% at reading 2, respectively. CONCLUSION: Spiral CT arthrography is valuable for the assessment of postoperative menisci, but the application of conventional definitions of meniscal tear to arthrographic findings in postoperative menisci can lead to overestimation of the clinical importance of meniscal lesions.

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OBJECTIVE: Our purpose was to determine the contribution of mammography followed by sonography for the detection of nonpalpable breast cancers in Breast Imaging Reporting and Data System (BI-RADS) density grades 1-4 breasts, in grades 1 and 2 breasts, and in grades 3 and 4 breasts. MATERIALS AND METHODS: The results of physical, mammographic, and sonographic examinations performed in 4236 patients were reviewed to determine the sensitivities of mammography and sonography for the detection of nonpalpable breast cancers and to calculate the relative risk for detecting nonpalpable breast cancers using sonography in comparison with mammography in density grades 1-4, grades 1 and 2, and grades 3 and 4 breasts. Sonography was performed after mammographic interpretation. RESULTS: Sensitivities of mammography and subsequent sonography for the detection of nonpalpable breast cancers were 69% and 88% in grades 1-4, 80% and 88% in grades 1 and 2, and 56% and 88% in grades 3 and 4 breasts, respectively. The relative risk for detecting nonpalpable breast cancers using sonography was statistically significantly greater than that for detecting nonpalpable breast cancers using mammography in grades 1-4 (relative risk, 1.29; p = 0.024) and in grades 3 and 4 (relative risk, 1.57; p = 0.013) but not in grades 1 and 2 (relative risk, 1.1; p = 0.445) breasts. CONCLUSION: Sonography is a useful adjunct after mammography for the detection of nonpalpable breast cancer, particularly in the dense breast.

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Our objective was to analyze the peripheral pulmonary arteries using thin-collimation multi-slice spiral CT. Twenty consecutive patients underwent enhanced-spiral multi-slice CT using 1-mm collimation. Two observers analyzed the pulmonary arteries by consensus on a workstation. Each artery was identified on axial and 3D shaded-surface display reconstruction images. Each subsegmental artery was measured at a mediastinal window setting and compared with anatomical classifications. The location and branching of every subsegmental artery was recorded. The number of well-visualized sub-subsegmental arteries at a mediastinal window setting was compared with those visualized at a lung window setting. Of 800 subsegmental arteries, 769 (96%) were correctly visualized and 123 accessory subsegmental arteries were identified using the mediastinal window setting. One thousand ninety-two of 2019 sub-subsegmental arteries (54%) identified using the lung window setting were correctly visualized using the mediastinal window setting. Enhanced multi-slice spiral CT with thin collimation can be used to analyze precisely the subsegmental pulmonary arteries and may identify even more distal pulmonary arteries.

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PURPOSE: To assess dual-detector spiral computed tomographic (CT) arthrography of the knee in the evaluation of anterior cruciate ligament (ACL) tears and associated meniscal lesions. MATERIALS AND METHODS: ACL and meniscal abnormalities in 125 consecutive patients who underwent dual-detector spiral CT arthrography of the knee were evaluated on the basis of both initial interpretations and retrospective review of CT images and were compared with arthroscopic findings. The sensitivity and specificity of CT arthrography for the detection of ACL tears and meniscal lesions in knees with abnormal ACLs were determined. RESULTS: The sensitivities and specificities for the detection of ACL tears were 90% and 96%, respectively, at initial interpretation and 95% and 99%, respectively, at retrospective interpretation. The sensitivities and specificities for the detection of meniscal tears in knees with abnormal ACLs were 92% and 88%, respectively, at initial interpretation and 96% and 94%, respectively, at retrospective interpretation. CONCLUSION: Dual-detector spiral CT arthrography of the knee is an accurate method for detecting ACL tears and associated meniscal lesions.

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Our objective was to determine the value of the Ottawa knee rules when applied by users with different levels of clinical training. We used a prospective patient survey by the medical students and surgery residents of a European university trauma centre. The study group consisted of 261 eligible patients who presented with acute knee trauma during a 6-month period. Radiography or follow-up was obtained for each patient. Data were separately analysed according to the degree of qualification of the initial examiner. The Ottawa knee rules had a sensitivity and a negative predictive value of 1.00. Variable degree of medical competence of the users did not alter the accuracy of the rules. Application of the rules would have reduced knee radiography requests by 25%. The Ottawa knee rules remain highly sensitive when applied by medical users with different levels of qualification, such as encountered in a teaching setting.

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PURPOSE: To assess dual-detector spiral CT arthrography in the evaluation of the entire knee cartilage obtained from cadavers. MATERIALS AND METHODS: Two independent observers characterized articular cartilage in 12 cadaver knees in which MR imaging and dual-detector spiral CT arthrography were performed and compared their findings to those found during macroscopic assessment. The sensitivity and specificity of MR imaging and spiral CT arthrography for detecting grade 2A or higher and grade 2B or higher cartilage lesions, the Spearman correlation coefficient between arthrographic and macroscopic grading, and kappa statistics for assessing interobserver reproducibility were determined. RESULTS: At spiral CT arthrography, sensitivities and specificities ranged between 80% and 88% for the detection of grade 2A or higher cartilage lesions and ranged between 85% and 94% for the detection of grade 2B or higher cartilage lesions. At MR imaging, sensitivities and specificities ranged between 78% and 86% and between 76% and 91% for the detection of grade 2A or higher and grade 2B or higher cartilage lesions, respectively. Spearman correlation coefficients between spiral CT arthrography or MR imaging and macroscopic grading of articular surfaces were 0.797 and 0.702, respectively. CONCLUSION: Dual-detector spiral CT arthrography of the knee is a valuable method for the assessment of open cartilage lesions of the entire knee.

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