Validation of quantitative computed tomography-derived areal bone mineral density with dual energy X-ray absorptiometry in an elderly Chinese population / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The performance of computed tomography X-ray absorptiometry (CTXA) against the dual energy X-ray absorptiometry (DXA) as standard has not been studied in Chinese population. The aim of this study was to evaluate the precision of this measurement and validate the value of quantitative computed tomography (QCT) by comparing CTXA results with DXA results in an elderly Chinese population.</p><p><b>METHODS</b>One hundred and three females of 46 to 76 years old and 49 males of 52 to 76 years old were recruited from the Prospective Urban Rural Epidemiology study. All subjects underwent hip scans by both QCT and DXA on the same day. For precision determination, 30 subjects had duplicate DXA hip scans. The hip QCT data of a subset of 27 subjects were separately analyzed by two observers and reanalyzed by one observer at a different time. The inter- and intra-observer variations of CTXA measurement were assessed, and the difference and correlation between CTXA and DXA results were analyzed.</p><p><b>RESULTS</b>The inter- and intra-observer variations of CTXA were 0.070 and 0.024 g/cm(2) in the femoral neck (FN), and 0.030 and 0.012 g/cm(2) in the total hip (TH), which were comparable to the DXA inter-scan variations (0.013 g/cm(2) for FN and 0.014 g/cm(2) for TH). The results of CTXA bone mineral density (BMD) were highly correlated with those of DXA (R(2) = 0.810 for FN and R(2) = 0.878 for TH). The BMD values of CTXA in FN and TH were lower than those of DXA by 21.0% and 17.8% (P < 0.05), respectively. However, after appropriate transformation, the difference was eliminated and a comparable T score could be obtained.</p><p><b>CONCLUSIONS</b>CTXA shows good agreement with DXA for the measurement of BMD in the proximal femur, which makes QCT suitable for the quantification of bone mineral content in the hip and helpful for the diagnosis of osteoporosis.</p>

The clinical and imaging features of pulmonary metastasis of giant cell tumor of bone / 中华放射学杂志

Objective To analyze the clinical and imaging features of pulmonary metastasis of giant cell tumor of bone for clinical diagnosis and treatment.Methods Five patients with histologically proven pulmonary metastasis from giant cell tumor of bone were reviewed,the imaging features and the progression of the pulmonary metastasis were evaluated.Results The first operation of primary tumor was curettages and then local recurrence was seen in all 5 cases.The interval to metastasis ranged from 5 to 26 months.Pulmonary metastasis was diagnosed by chest radiographs in 4 cases and CT in all 5 cases.The imaging findings included solitary solid nodule (n =1),multiple solid nodules and mass (n =5),multiple groundglass nodules (n =1) and complex form (n =2).The dynamic follow-up CT findings showed spontaneous regress nodules (n =1),metastasis occurring again 19 months after surgery of solitary nodule (n =1),some solid nodules unchangable for a long time in 3 patients with multiple nodules.Conclusions The dynamic follow-up CT findings of pulmonary metastasis of giant cell tumor of bone are specific.The regular follow-up could play an essential role in early detection and prognosis of pulmonary metastasis within 2 years after primary tumor diagnosed.

Assessment of the degenerative cartilage of hip dysplasia with three dimensional delayed enhanced MRI of cartilage / 中华放射学杂志

Objective To evaluate the feasibility of assessing osteoarthritis (OA) in hip dysplasia using 3D delayed gadolinium-enhanced MRI of cartilage (dGEMRIC).Methods Thirty-five hips in 20 patients with radiographic evidence of hip dysplasia underwent 3D-dGEMRIC scanning.Clinical symptoms were assessed with the Western Ontario and McMaster Universities Osteoarthritis ( WOMAC ) questionnaire.Radiographic measurement of lateral center-edge angle and T(o)nnis grading were performed on the X-rays.Hips of T(o)nnis grade 1were included in the group of hips with early OA,while the hips with no evidence of OA and without pain symptom were included in the group of hips with normal morphology.The 3D-dGEMRC scans were completed on a 1.5 T MR scanner.The data of 3D-dGEMRIC was reconstructed radically.The dGEMRIC indices were measured on six sites of periphery zones of hip cartilage on reconstructed images.The dGEMRIC indices among different groups were analyzed by non-parametric tests.The differences of dGEMRIC indices among six sites in the group of early OA or the group of normal morphology were analyzed by Wilcoxon test.Results The mean dGEMRIC indices of six sites were lower in group of T(o)nnis grade 1than in group of T(o)nnis grade 0 ( Z =- 2.149,P =0.032 ),and lower in group of T(o)nnis grade 2 than in group of T(o)nnis grade 1( Z =- 1.990,P =0.047 ).The dGEMRIC indices of the anterior site,anterosuperior site,superior-anterior site,and superior site were significantly different between the group of hips with early OA and the group of hips with normal morphology (Z =-2.333--2.041,all of the P values were lower than 0.05).In the group of hips with normal morphology,the dGEMRIC indices of superior-anterior site of hip were lower than superior site(P =0.028).In the group of hips with early OA,the dGEMRIC indices of superior-anterior site were lower than the other sites except for anterior-superior site ( Z =- 3.041- - 2.277,all of the P values were lower than 0.05 ).Conclusions 3 D-dGEMRIC might be a sensitive technique for detection of glycosaminoglycans alteration in early OA and staging of OA in hip dysplasia.Radial reconstruction could provide an accurate assessment of OA,and the results demonstrated that early cartilage alteration could be detected in the anterior to superior sites of hips,and the earliest cartilage alteration may occur in the superior-anterior site of hips.