Diagnostic value of dual-phase contrast enhancement CT combined with virtual non-enhanced images by dual-energy CT in clear cell renal cell carcinoma / 中华放射学杂志

ABSTRACT

Objective To explore the diagnositic value of dual-phase contrast enhancement CT combined with virtual non-enhanced images by dual-energy CT in clear cell renal cell carcinoma.Methods Sixty patients who were suspected of clear cell renal cell carcinoma underwent non-enhanced CT and contrast enhancement CT of early interface-phase between cortex -medulla and parenchymal phase on a dual-energy CT.The true non-enhanced kidney CT(TNCT) was performed in a single-energy acquisition mode,but the dual-phase contrast enhancement CT were performed in a dual-energy mode of 80 kV and 140 kV respectively.The virtual non-enhanced CT ( VNCT ) images were derived from the data of early interfacephase using liver virtual non-contrast software.The diagnosises according to VNCT combined dual-phase contrast enhancement CT and dual-phase contrast enhancement CT only were made respeetively and compared with x2 test.Between the true non-contrast CT and the virtual non-contrast CT,the image quality was compared with Wilcoxon test ; The radiation dose of volume CT dose index ( CTDlvol ) and dose length product(DLP) in a single-phase and total examination,the mean CT HU values of the tumours werecompared with t test.Results The accuracy of VNCT combined dual-phase contrast enhancement CT was higher than that of dual-phase contrast enhancement CT only [93.3％ ( 56/60 ) vs.78.3％ ( 47/60 ) ; x2 =5.6,P ＜0.05].The detective ability (score) of VNCT was near to that of TNCT and the difference was not obvious( Z =0.00,P ＞ 0.05 ). The radiation dose of volume CT dose index ( CTDIvol ) and dose length product(DLP) in a single phase and total examination of VNCT[(8.85 ± 1.28) mGy,(196.45 ±21.12) mGy·cm,(17.69±2.35) mGy,(392.90±42.25) mGy · cm] were lower than that of TNCT [( 10.20 ± 1.44 ) mGy,( 218.29 ± 29.60 ) mGy · cm,( 30.61 ± 3.27 ) mGy and ( 654.86 ± 88.81 ) mGy ·cm],t =4.21,3.58,23.63,16.12 respectively,P ＜0.05.The mean CT HU values of tumours on VNCT images was higher than that on TNCT images and the difference was significant [(39.37 ± 6.35 ) vs.(34.94 ± 7.00 )HU,t =- 14.39,P ＜ 0.05].Conclusions The diagnositic value of dual-phase contrast enhancement CT combined virtual non-enhanced CT by dual-energy CT for clear cell renal cell carcinoma was obvious,most tumours can be diagnosed correctly,and the radiate dose can be decreased obviously,the normal single-energy non-enhanced and contrast enhancement CT might be replaced in the future.