不同显像时间窗对^11C—CFT PET／CT显像测多巴胺转运蛋白分布半定量值的影响

Influence of scanning time window on the binding potentials of dopamine transporter in the brain of healthy volunteers with nC-CFT PET imaging

目的通过^11C-甲基-N-2β-甲基酯-3β-（4-氟苯基）托烷（CFT）PET／CT显像，观察不同显像时间窗基底节区DAT分布的半定量值，寻找最佳显像时间窗并分析不同年龄和性别间的DAT分布差异。方法将31名[男20名，女11名，平均年龄（55．7＋2．3）岁]知情同意的健康受试者按随机区组法分为年龄匹配的3组，分别在注射^13C—CFT后40～60min、60～80min和80～100min进行PET／CT静态显像，计算机自动勾画ROI，获得不同显像时间窗内尾状核及壳核DAT分布的半定量值（尾状核或壳核放射性计数／顶枕叶放射性计数-1），使用单因素方差分析及最小显著差异t检验对不同脑区半定量值进行比较。采用两独立样本t检验比较不同年龄（≥60岁和〈60岁）和性别患者最佳显像时间窗内尾状核及壳核半定量值的差异。结果左侧尾状核（2．08±0．06、1．75±0．07和1．77±0．12）、右侧壳核前部（2．33±0．06、1．95±0．09和2．08±0．12）、双侧壳核后部（左：1．88±0．06、1．55±0．88和1．72±0．09，右：1．98±0．07、1．61±0．09和1．69±0．12）的DAT分布半定量值在3个时间窗内的差异具有统计学意义（F=3．588、3．345、4．479和3．557，均P〈0．05）。其中，40～60min显像与60-80min相比，左侧尾状核、右侧壳核前部、双侧壳核后部半定量值差异具有统计学意义（均P〈0．05）；与80～100min相比，左侧尾状核半定量值差异具有统计学意义（P〈0．05）。而60～80min与80～100mira显像差异均不具有统计学意义（均P〉0．05）。〈60岁的健康人尾状核、壳核DAT分布半定量值高于≥60岁者（t值分别为-3．260、-3．090、-3．270、-3．190、-2．270及-3．110，均P〈0．05）；不同性别尾状核及壳核DAT分布差异均无统计学意义（t值分别为0．367、0．522、0．144、0．524、0．166及0．004，均尸〉0．05）。结论脑内^13C—CFT在注射后60rain达到稳定，^13C—CFTPET／CT显像检测DAT分布的最佳显像时间窗为注射后60～80min；≥60岁和〈60岁健康人的DAT分布有差异。显像时间窗的统一和不同年龄段的半定量正常值的建立，有助于^13C—CFTPET／CT显像在PD诊断方面的临床应用。

Objective To find the optimal scanning time window and then set up the normal hind- ing potentials （BPs） of 2β-carbomethoxy-3β-（4-fluorophenyl） -（ N-11 C-methyl） tropane （11 C-CFT） DAT PET/CT imaging. Methods Thirty-one healthy volunteers （ 20 males, 11 females, average age ： （ 55.7 ± 2.3 ） years） , who all gave written informed consent, were divided into three age and gender-matched groups according to block randomization. Each group underwent static PET/CT scan in different time windows from 40-60 min, 60-80 min to 80-100 min after ^13C_CFT injection. To determine the best scanning time window, the ratios of caudate and putamen of all volunteers were analyzed using automatic ROI method （ caudate （putamen）/parieto-occipital cotex-1 ） and compared by one-way analysis of variance and the least significant difference （LSD） t test. The ratio of the same area between different age-groups and gender-groups was compared with independent two-sample t test. Results Ratios of left caudate （2.08±0.06, 1.75±0.07 and 1.77±0.12 respectively）, right anterior putamen （2.33±0.06, 1.95±0.09 and 2.08±0.12 respectively） and bilateral posterior putamen （ left ： 1.88±0.66, 1.55±0.88 and 1.72±0.09 ; right ： 1.98±0. 07, 1.61±0.09 and 1.69±0. 12） were all different in three time windows （F=3.588, 3.345, 4.479, 3.557, all P〈0.05）. There were significant differences in ratios of left caudate, right anterior and bilateral posterior putamen between 40-60 min and the 60-80 min （all P〈0.05 ） , as well as the ratios of left candate between 40-60 min and the 80-100 rain group （P〈0.05）. While no valid differences in ratios of those areas were shown between the groups of 60-80 min and 80-100 rain scanning time window （all P〉0.05）. DAT densities in fight and left side of caudate, anterior and posterior putamen were significantly lower in the group over 60 years of age than those under 60 years （t =-3.260, -3.090, -3.270, -3.190, -2.270, -3.110, all P〈0.05）, but were not different between gender-groups （t= 0.367, 0.522, 0.144, 0.524, 0. 166, 0. 004, all P〉 0. 05）. Conclusions Sixty min after injection of HC-CFT, the BPs achieve stable stage, so the best scan- ning time window of 11 C-GET DAT PET imaging was 60-80 min after injection. Identification of normal DAT distribution and understanding of normal BPs of ^11C-CFT are necessary before its clinical application.