RESUMO
Objective To analyze the characteristics and to evaluate the application of quantitative CT spectral parameters in patients with suspected lung cancer.Methods One hundred and thirty two patients with occupying lesions of the lung underwent chest plain and two-phase contrast enhanced CT scan with gemstone spectral imaging (GSI) mode.The CT images of patients with confirmed lung cancer by pathological evidence were analyzed with GSI viewer.Optimal energy value supplying optimal contrast-tonoise ratio (CNR) was recorded.The CT values of lesions at 40 keV,70 keY and optimal energy level were measured.Spectral curve slope at different intervals of 40-70 keV,40-100 keV and 40-140 keV was computed.Effective atomic number (Zeff),iodine concentration (IC) and water concentration (WC) were measured and analyzed by statistical methods.Results Sixty six patients with confirmed lung cancer were included in the analysis.The optimal energy values for optimal CNR on plain scan,arterial phase and venous phase were (63.09±5.33) keV,(52.65±6.44) keV and (54.06±5.53) keV,respectively.The difference of CT values at different energy levels on each scan phase was statistically significant (F=4.561,P=0.025).The spectral curve slope values among three different energy intervals were significantly different (F=2.137,P＜0.001).The differences of the slope between arterial phase and venous phase at same energy interval were not significant (40-70 keY:t=1.165,P=0.248;40-100 keV:t=1.102,P=0.274;40-140 keV:t=1.118,P=0.268).Zeff on plain scan,arterial phase and venous phase was 7.73±0.14,8.35±0.37 and 8.39±0.30,respectively.There was positive correlation between IC and Zeff on enhanced phase (arterial phase:r=0.998,P＜0.001;venous phase:r=0.998,P＜0.001).Conclusion CT spectral imaging can supply the optimal energy value for optimal CNR.CT value at optimal energy level and spectral curve slope at 40-140 keV are suitable for analysis.IC and Zeff can be used jointly in evaluation of patients with suspected lung cancer.
RESUMO
Objective To evaluate the diagnostic value of 64-slice VCT reconstruction techniques in the diseases of joints of foot and hand.Methods 50 patients with diseases of joints of foot and hand underwent MSCT scans,the data were reconstructed,including multiplanar reconstruction(MPR),maximum intensity projection(MIP),shaded surface display(SSD)and volume rendering(VR),the results were analysed.Results 33 patients with fractures,40 and 51 fractures were found by X-ray and MPR,VR,respectively.The joint surface involved in 7 fractures,which was best with VR and MPR to show the whole fractures.SSD was better to demonstrate the soft tissue and the vessels of the skin.3D bone reconstruction with MIP was better than plain film in showing the fractures in 4 patients with plaster external fixation.Conclusion 64-slice VCT reconstruction techniques are effective in diagnosis of the diseases of joints of foot and hand.
