Objective To evaluate the early appearance of SARS on chest CT scan and its role in the early diagnosis Methods Forty cases of SARS in keeping with the criteria of the Ministry of Health had chest CT scans within 7 days of onset of symptoms, and CR chest X-ray films were available as well These chest X-rays and CT images were retrospectively reviewed to determine if there were any abnormalities on the images The lesions on the chest CT images were then further analyzed in terms of the number, location, size, and density Results Positive abnormalities on chest CT scans were revealed in all 40 SARS cases Positive findings on CR chest films were showed in only 25 cases, equivocal in 6, and normal in 9 cases The main abnormalities seen on CT and X-rays were pulmonary infiltrations varied markedly in severity 70% cases had 1 or 2 lesions on chest CT scan, 30% cases had 3 or more lesions The lesions seen on chest CT scan tended to be ground-glass opacification, sometimes with consolidation which was very faint and inhomogeneous, easily missed on chest X-rays Typically the lesions were located in the periphery of the lung, or both central and peripheral lung, but very rare in a pure central location They were commonly in the shape of patch or ball Conclusions Chest CT scan is much more sensitive in detecting the lesions of the lung in SARS The early appearance of SARS on chest CT scan is characteristic but non-specific, indicating that chest CT scan plays a very important role in the early diagnosis and differential diagnosis of SARS

Objective To analyze the imaging findings of osteosarcomatosis, and to explore the value of imaging in the diagnosis of osteosarcomatosis.Methods Clinical data and imaging findings in 15 cases of osteosarcomatosis were reviewed.All of them had conventional X-ray films, 13 cases had CT scanning, 11 cases had ECT scanning, 5 cases had MR scanning, and 4 cases with DSA.Results Eight primary lesions were located in the distal femur, 5 in the proximal tibia, 1 in humerus, and 1 in clavicle.Secondary lesions were scattered in proximal tibia in 8, distal femur in 6, spine in 6, pelvis in 2, and other sites.The primary lesion showed typical X-ray finding of osteosarcoma, but lesions at other position showed mainly high density of osteogenesis in all 15 cases.In 13 cases, CT played an important role in defining the extent of the tumor and soft tissue masses.CT scanning was sensitive in detecting osteosclerotic lesions in the bone marrow.In 5 cases, MRI was useful in delineating the extent of tumor and soft tissues mass, as well as the extent of tumor in bone marrow.ECT had the capacity of showing the radionuclide concentration of tumor focus in the whole body in a single scan in 11 patients.Conclusion Osteosarcomatosis has multiple lesions all over the body.Imaging modalities including X-ray plain film, CT, MRI, and ECT are all important in finding the lesions and in diagnosing osteosarcomatosis.

Objective To investigate the value of time-intensity curve of dynamic contrast enhancement MR imaging in the discrimination of benign and malignancy in musculoskeletal tumors. Methods Ninety patients were examined with fast acquisition with muhiphase enhanced fast GRE series. The TIC of lesions were obtained using slope images in which pixel intensity reflected the slope value. The curves were classified according to their shapes as type Ⅰ , washout enhancement; type Ⅱ, plateau enhancement; type Ⅲ, gradual enhancement. Taking pathological diagnosis as gold standard, the power of the maximal enhancement slope and curve types in discriminating benign and malignant lesions was evaluated by appropriate statistic analysis. Results There were 49 malignant and 44 benign lesions. The distribution of curve types for malignant tumors was type Ⅰ 75.5% ( 37/49), type Ⅱ 24. 5% (12/49). While the numbers for benign tumors was type Ⅰ 59. 1% ( 26/44 ), type Ⅱ 15.9% ( 7/44 ) and type Ⅲ 25.0% ( 11/44 ), respectively. The patterns of curve types in malignant lesions were different from benign lesions significantly ( χ2 = 14. 008, P < 0. 01 ). The slope value in benign lesion was 6. 80 + 3. 35 and that in malignant lesion was 6. 80±2. 71. The difference was not statistically significant( t = 0. 008, P > 0. 05 ). Type Ⅰ and type Ⅱ (excluding lesions with typical benign morphology ) were suggestive of malignant tumors. Type Ⅲ was indicator of a benign lesion. The diagnostic indices for the shape of TIC criterion were: sensitivity 100%, specificity 50%, positive predictive value 78%, negative predictive value 100% and accuracy 82%, respectively. Conclusion Combined with the characteristic of morphology, the TIC improves the power of MR imaging in discriminating benign from malignant musculoskeletal tumors.