The influence of the maximal value and peak enhancement value of arterial and venous enhancement curve on CT perfusion parameters and signal-to-noise ratio

Abstract

Objective To explore the influence of the maximal value and peak enhancement value of arterial and venous enhancement curve on CT perfusion parameters and signal-to-noise ratio(SNR). Methods Seventeen patients underwent brain CT perfusion scanning.All row data were analyzed with perfusion software for 6 times,and get different arterial and venous enhancement curves for each patient.The maximal values and peak enhancement values of each arterial and venous enhancement curves,as well as mean perfusion parameters including cerebral blood flow(CBF)、cerebral blood volume(CBV)、mean transit time(MTF),permeability surface area product(PS),and their standard deviations(SD)in homolateral white and gray matter were measured and recorded.SNR was calculated by dividing the mean perfusion parameter value by its SD.Pearson correlation analysis and two-tailed paired Student t test were used for statistics.Results The maximal values and peak enhancement values of arterial and venous curves were correlated with mean SNR_(CBF),SNR_(CBV)and SNR_(MTT)in both white matter and gray matters(r value range: 0.332—0.922,P0.01).The maximal value of venous curve was also correlated with SNR_(PS)in white matter(r=0.256,P0.05).No correlation was found either between SNR_(PS)(in both white matter and gray matters)and arterial peak enhancement values,the maximal values and venous peak enhancement values,or between SNR_(PS)(in gray matter)and the maximal values of venous curve(r value range:-0.058— 0.210,P0.05).(2)Mean CBF,CBV and PS values in the group with low venous peak enhancement values were significantly different from the group with high venous peak enhancement values in both white and gray matters(t value range:3.830—5.337,P0.01),but no significant difference in mean MTT values.There were no significant differences for all mean perfusion parameter values in both the low and high arterial peak enhancement values groups(t value range:-0.987—1.197,P0.05).Conclusions The mean perfusion parameters and SNR are influenced by the maximal values and peak enhancement values of the arterial and venous curves.Peak enhancement of arterial and venous curves should be adjusted to higher level to make parameter values more reliable and increase the SNR.