ABSTRACT
Objective To explore the value of dual-source CT spectrum energy curve and iodine quantification in determining the degree of differentiation of clear cell renal carcinoma(ccRCC).Methods The radiographic data of 38 cases with pathologically confirmed ccRCC were analyzed retrospectively.All patients underwent dual-source CT,cortical phase and nephrographic phase dual energy scan,including 22 well-moderated differentiated(gradeⅠ,gradeⅡ)and 16 poorly differentiated neoplasms(gradeⅢ,gradeⅣ).The slope of spectrum energy curve (40-70 keV,70-100 keV,100-140 keV)and the normalized iodine concentration (NIC)between the two grades were compared. Results In the spectrum energy curve 40-70 keV and 70-100 keV segment interval,the slope of spectrum of well-moderated differentiated group was higher than that of poorly differentiated group,the difference was statistically significant(P<0.05).In the 100-140 keV segment interval,the slope of spectrum of well-moderated differentiated group was higher than that of poorly differentiated group, but the difference was insignificant(P>0.05).The NIC of well-moderated differentiated group was significantly higher than that of poorly differentiated group(P<0.05).Conclusion The slope of spectrum energy curve and NIC are correlated with the differentiation degree of ccRCC.The slope of spectrum energy curve and iodine quantification of dual-source CT could be used as new methods for preoperative grading of ccRCC.
ABSTRACT
OBJECTIVE: To correlate CT parameters on detector-based dual-energy CT enterography (DECTE) with Crohn's disease activity index (CDAI) and externally validate quantitative CT parameters. MATERIALS AND METHODS: Thirty-nine patients with CD were retrospectively enrolled. Two radiologists reviewed DECTE images by consensus for qualitative and quantitative CT features. CT attenuation and iodine concentration for the diseased bowel were also measured. Univariate statistical tests were used to evaluate whether there was a significant difference in CTE features between remission and active groups, on the basis of the CDAI score. Pearson's correlation test and multiple linear regression analyses were used to assess the correlation between quantitative CT parameters and CDAI. For external validation, an additional 33 consecutive patients were recruited. The correlation and concordance rate were calculated between real and estimated CDAI. RESULTS: There were significant differences between remission and active groups in the bowel enhancement pattern, subjective degree of enhancement, mesenteric fat infiltration, comb sign, and obstruction (p < 0.05). Significant correlations were found between CDAI and quantitative CT parameters, including number of lesions (correlation coefficient, r = 0.573), bowel wall thickness (r = 0.477), iodine concentration (r = 0.744), and relative degree of enhancement (r = 0.541; p < 0.05). Iodine concentration remained the sole independent variable associated with CDAI in multivariate analysis (p = 0.001). The linear regression equation for CDAI (y) and iodine concentration (x) was y = 53.549x + 55.111. For validation patients, a significant correlation (r = 0.925; p < 0.001) and high concordance rate (87.9%, 29/33) were observed between real and estimated CDAIs. CONCLUSION: Iodine concentration, measured on detector-based DECTE, represents a convenient and reproducible biomarker to monitor disease activity in CD.