Assessment of consistency of the whole tumor and single section perfusion imaging with 256-slice spiral CT: a preliminary study / 中华放射学杂志

ABSTRACT

Objective To determine the consistency between quantitative CT perfusion measurements of colorectal cancer obtained from single section with maximal tumor dimension and from average of whole tumor,and compare intra-and inter-observer consistency of the two analysis methods.Methods Twenty-two patients with histologically proven colorectal cancer were examined prospectively with 256-slice CT and the whole tumor perfusion images were obtained.Perfusion parameters were obtained from region of interest (ROI) inserted in single section showing maximal tumor dimension,then from ROI inserted in all tumor-containing sections by two radiologists.Consistency between values of blood flow (BF),blood volume (BV) and time to peak (TTP) calculated by two methods was assessed.Intra-observer consistency was evaluated by comparing repeated measurements done by the same radiologist using both methods after 3 months.Perfusion measurements were done by another radiologist independently to assess inter-observer consistency of both methods.The results from different methods were compared using paired t test and Bland-Altmnan plot.Results Twenty-two patients were examined successfully.The perfusion parameters BF,BV and TTP obtained by whole tumor perfusion and single-section analysis were (35.59 ± 14.59) ml · min-1 · 100 g-1,(17.55 ±4.21) ml · 100 g-1,(21.30 ±7.57) s and (34.64 ± 13.29)ml· min-1 · 100 g-1,(17.61 ±6.39)ml± · 100 g-1,(19.82 ±9.01)s,respectively.No significant differences were observed between the means of the perfusion parameters (BF,BV,TTP)calculated by the two methods (t =0.218,-0.033,-0.668,P ＞ 0.05,respectively).The intra-observer 95％ limits of consistency of perfusion parameters were BF-5.3％ to 10.0％,BV-13.8％ to 10.8％,TTP-15.0％ to 12.6％ with whole tumor analysis,respectively; BF-14.3％ to 16.5％,BV-24.2％ to 22.2％,TTP-19.0％ to 16.1％ with single section analysis,respectively.The inter-observer 95％ limits of consistency of perfusion parameters were BF-8.0％ to 8.3％,BV-10.9％ to 11.5％,TTP -14.5％ to 11.1％ with whole volume analysis,respectively; BF-10.2％ to 14.1％,BV-19.0％ to 17.6％,TTP-22.0％ to 24.0％ with single section analysis,respectively.Conclusion There was no statistically different between the single section and whole volume analysis of tumor perfusion CT.The whole volume perfusion analysis apparently improves intra-and inter-observer consistency and can reflect the whole tumor angiogenesis more accurately and repeatedly.