Study on the selection of reference vessel on multi-slice spiral CT perfusion in patients with nasopharyngeal carcinoma after radiation therapy / 中华放射学杂志

ABSTRACT

ObjectiveTo investigate the effect of different reference vessel groups on CT perfusion in patients with nasopharyngeal carcinoma (NPC) after radiation therapy,and explore the feasibility of substitution of reference vessel.MethodsThirty patients with NPC after radiation therapy were divide into two groups,recurrence group ( n =19) and fibrosis group ( n =11 ).All patients underwent CT perfusion scans,and the CT parameters were calculated with different arterial input and vein output in order to study their differences.The vessels were internal carotid artery-internal jugular vein( ICA-IJV group),external carotid artery-retomandibular vein (ECA-RTV group)and external carotid artery-internal jugular vein( ECAIJV group) respectively.The differences of the CT parameters between local recurrence group and fibrosis group were compared among the various vessel groups by rank sum test.With the help of receiver operating characteristic curve (ROC),the diagnostic efficiencies were compared by the area under the ROC curve (AUC).ResultsIn ICA-IJV group,ECA-RTV group and ECA-IJV group,bloood flow(BF) of local recurrence group were 201.88,439.59,252.23 ml · min-1 · 100 g-1,while BF of fibrosis group were 98.96,180.50,106.55 ml · min-1 · 100 g-1.Blood volume (BV) of local recurrence group were 6.71,12.39,6.70 ml/l00 g,while BV of fibrosis group were 2.35,4.76,2.95 ml/100 g.Mean transit time (MTT) of local recurrence group were 1.66,1.50,1.56 s,while MTT of fibrosis group were 2.13,1.96,1.79 s.Permeability surface (PS) of local recurrence group were 19.31,36.39,15.22 ml · min- 1 ·100 g-1,while they were 16.58,29.08 ,16.63 ml · min-1 · 100 g-1 in the fibrosis group.The differencesof BF and BV between the local recurrence group and fibrosis group were statistically significant in each vessel group (P ＜ 0.05 ) but MTT and PS showed no significant difference( P ＞ 0.05 ).In ICA-IJV group,the AUC of BF,BV,MTT,PS were 0.909,0.947,0.677,0.703,respectively.BF,BV,MTT,PS in ECA-RTV group were 0.938,0.967,0.648,0.679 respectively,and those in ECA-IJV group were 0.861,0.890,0.641,0.656 respectively.However,AUC of BF and BV of three groups all had significant difference ( P ＜ 0.01 ).ConclusionsBoth BF and BV values calculated by three pairs of reference vessels had enough diagnosis efficiency for local recurrence and fibrosis,so all of the three groups of vessels may substitute each other in CT perfusion.