多层螺旋CT灌注成像对鼻咽癌放疗后患者感兴趣血管选择的研究

目的 研究不同感兴趣血管选择对鼻咽癌放疗后局部复发瘤和纤维化灶CT灌注参数的影响,探讨鼻咽癌放疗后患者CT灌注成像时选择替代感兴趣血管的可行性.方法 对复发组(19例)和纤维化组(11例)进行CT灌注后,采用颈内动脉-颈内静脉(颈内-颈内组)、颈外动脉-下颌后静脉(颈外-下颌后组)和颈外动脉-颈内静脉(颈外-颈内组)分别作为3组感兴趣血管测量复发组和纤维化组患者的灌注参数,研究其差异性；利用ROC曲线计算3组灌注参数对复发瘤的诊断效能.对所获数据的组间差异进行秩和检验.结果 CT灌注感兴趣血管颈内-颈内、颈外-下颌后、颈外-颈内组的复发组血流量(BF)M值分别为201.88、439.59、252.23ml· min-1·100g-1,纤维化组分别为98.96、180.50、106.55 ml·min-1·100 g-1;复发组血容量(BV)M值分别为6.71、12.39、6.70 ml/100 9,纤维化组分别为2.35、4.76、2.95ml/100 9；复发组平均通过时间(MTT)M值分别为1.66、1.50、1.56 s,纤维化组分别为2.13、1.96、1.79 s；复发组表面通透性(PS)M值分别为19.31、36.39、15.22 ml· min-1·100g-1,纤维化组分别为16.58、29.08、16.63 ml· min-1·100g-1；各组内复发组与纤维化组的BF、BV值差异均有统计学意义(P值均＜0.05),而MTT及PS值差异均无统计学意义(P值均＞ 0.05).颈内-颈内组BF、BV、MTT、PS的ROC曲线下面积(AUC)分别为0.909、0.947、0.677、0.703;颈外-下颌后组分别为0.938、0.967、0.648、0.679；颈外-颈内组分别为0.861、0.890、0.641、0.656;分别与AUC的诊断阈值(0.5)比较,3组灌注参数BF、BV测量值的AUC值具有诊断效能(P值均＜0.01).结论 用3组不同感兴趣血管进行CT灌注成像,BF、BV对鼻咽癌放疗后局部复发瘤及纤维化灶均具有鉴别诊断效能；3组不同感兴趣血管可相互替代完成鼻咽癌放疗后的CT灌注检查.

Study on the selection of reference vessel on multi-slice spiral CT perfusion in patients with nasopharyngeal carcinoma after radiation therapy

Objective To 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.Methods Thirty 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).Results In 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 ).Conclusions Both 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.