Comparison of PET/CT and electronic endoscopy for measuring the length of esophageal squamous cell carcinoma / 中华核医学与分子影像杂志

ABSTRACT

Objective To compare 18 F-FDG PET/CT and electronic endoscopy for measuring the length of esophageal squamous cell carcinoma (ESCC) and to evaluate the optimal SUV threshold for contour determination of the size of the lesion.Methods Twenty-four patients (19 males and 5 females,median age59 years) with histologically confirmed ESCC were enrolled.Three patients had stage Ⅱ,14 had stage Ⅲ and 7 had stage Ⅳ diseases.PET studies were performed before treatment.The length of ESCC was measured on FDG PET imaging using different SUV thresholds of 2.0 (L2.0),2.5 (L2.5),3.0 (L3.0),3.5 (L3.5),and 35％(L35),40％(L40),45％(L45),50％(L50),55％(L55) of SUVmax.The length of ESCC on PET imaging was compared with the length of gross tumor in vivo measured by electronic endoscopy (Lst) to determine the optimal threshold of SUV using paired t test.Pearson correlation analysis was used to assess the correlation.Results The SUVmax of primary tumor was 14.51±5.72 and the Lst was (5.27± 2.45) cm.The length was in a descending order of L2.0,L2.5,Lst,L3.0,L3.5,L35,L40,L45,L50 and L55 when using different criteria.There were significant differences between the Lst and the lengths measured on PET except those by L2.5 and L3.0((5.65±2.69) cm,(5.11±2.51) cm; t=-1.74 and 0.76,both P＞0.05).The lengths measured on PET by all criteria were significandy correlated with the Lst,respectively,with the better r values by L3.5(0.935),L2.5(0.920) and L3.0(0.919) (all P＜0.01).When SUVm~＜15,there were no significant differences between the Lst ((4.82±2.14) cm) and L2.5((4.95±2.76) cm),L3.0((4.45±2.50) cm) and L35((4.42±1.85) cm),respectively (t=-0.439,1.299,2.011,all P＞0.05).The best correlation (r=0.953,P＜0.05) was between Lst and Lz5.When SUVmax ≥ 15,there was no significant difference between Lst ((5.67±2.64) cm) and L3.0((6.11±2.61) cm; t=-0.897,P＞0.05; r=0.791,P＜ 0.05).Conclusions For better correlation of ESCC lesion size,it is suggested that the optimal threshold of SUV for contouring is 2.5 for tumor SUVmax＜15,and 3.0 for tumor SUVmax ≥ 15.A larger sampling size is needed for further confirmation or modification.