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Objective To evaluate the feasibility of adaptive statistical iterative reconstruction-V (ASIR-V) to improve image quality in low-dose CT colonography.Methods A series of thirty artificial polyps were established by ligation in an isolated segment of porcine colon.Volume data was acquired on Revolution CT scanner (GE,USA) with High Definition scan mode and different scan parameter combinations:120 kVp with different mAs (10,30,50,70,90,100,120,140,160,180,200,220,240,260,respectively).Images were reconstructed with six different ASIR-V levels of 0 (filtered back projection,FBP),10％,30％,50％,70％ and 90％.Two radiologists were blinded to measure and analyze the objective data independently,including image noise (SD),signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).The kappa test was used to assess interobserver agreement in subjective image quality score.ICC test was used to examine the consistency of the measurements between two observers.SD,SNR,CNR were performed for statistical analysis in different tube current and different levels of ASIR-V using variance analysis (ANOVA).Results Interobserver agreement for subjective image quality score was good with a kappa value of 0.683.The variation of the tube current(r =0.734,P =0.000) and ASIR-V level(r =0.220,P =0.044) is related to the subjective score of image quality.Under the condition of the same tube current,image quality score of 50％ ASIR-V reconstruction was the highest.Two objective data consistency is good.The differences of image noise (F =423.58,P ＜ 0.05),SNRs(F =124.26,P ＜ 0.05) and CNRs (F =1 030.17,P ＜ 0.05) of different tube current and different levels of ASIR-V reconstruction were statistically significant.In the same tube current,with increased levels of ASIR-V,image noise reduced,CNRs increased.Only in 10,120,140,160,220,240,260 mA,the differences of SNRs were statistically significant(F =8.75-31.36,P ＜ 0.05).For the same level of ASIR-V reconstruction,with the increase of tube current,the image noise decreased,SNR and CNR increased gradually.Conclusions In the CT colonography,the application of ASIR-V algorithm can significantly reduce the noise and enhance the image contrast noise ratio and improve image quality.ASIR-V algorithm with 50％ has better performance in reducing CT image noise.
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Objective To evaluate the value of ADC and FA of diffusion tensor imaging (DTI) in differentiating clear cell renal cell carcinoma (ccRCC) and transitional cell carcinoma (TCC) of kidney pelvis.Methods Thirty-eight histopathology proven ccRCC and TCC patients (29 cases of ccRCC and 9 cases of TCC) were retrospectively enrolled.All the patients were performed abdominal MR fat saturation T1WI,fat saturation T2WI,LAVA and DTI (b=0,600 s/mm2).MR images were reviewed and analyzed by two radiologists in a double-blind manner with the value of ADC and FA measured using the Functool on AW 4.4 workstation.The data of two observers were analyzed with intra-class correlation coefficients (ICC) to assess inter-observer consistency.The differences of ADC values and FA values between ccRCC and TCC were compared by independent t-test.The ROC curves were used to analyze and compare the diagnostic value of DTI in differentiating ccRCC and TCC.Results The inter-observer agreements were good (ICC＞0.75).The ADC value of ccRCC was statistically higher than that of TCC ([2.03 ± 0.49] × 10-3 mm2/s vs [1.57 ± 0.43] × 10-3 mm2/s,P =0.015).But the FA value of ccRCC was statistically lower than that of TCC ([0.24±0.10] vs [0.42±0.22],P=0.002).The area under the ROC curve of ADC was 0.761 (P＜0.05),and the sensitivity and specificity were 79.3％ and 77.8％.The ADC threshold for differentiating ccRCC from TCC was 1.59× 10-3 mm2/s.The area under the ROC of FA was 0.762 (P＜ 0.05),and the sensitivity and specificity were 66.7 ％ and 93.1％.The FA threshold for differentiating ccRCC from TCC was 0.326.Conclusion MR DTI can effectively discriminate ccRCC and TCC.FA values has good diagnostic specificity in differentiating between ccRCC and TCC.
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OBJECTIVE:To conduct supplementary study for quality standard for Compound vaccariae tablets. METHODS:TLC was used for the qualitative identification of Vaccariae;HPLC was used to determine the contents of vaccarin and anthranilic acid. The column was YMC-Pack Pro C18 with mobile phase of methanol- 0.3% phosphpric acid(gradient elution)at the flow rate of 1.0 ml/min,the detection wavelength was 280 nm,column temperature was 35 ℃ and volume size was 10 μl. RESULTS:The chromatographic spots were clear and well-separated without interference from negative control. The linear range was 0.055 7-2.228 7μg(r=0.999 9)for vaccarin and 2.011 4-40.227 9 μg(r=0.999 9)for anthranilic acid;RSDs of precision,stability and reproduc-ibility tests were no more than 1.01%;average recoveries were respectively 99.69%(RSD=1.11%,n=6) and 99.84%(RSD=1.18%,n=6). CONCLUSIONS:The method is simple,rapid and accurate with good reproducibility,and can be used for quality control of Compound vaccariae tablets.