对比剂铁羧葡胺在正常兔MR脑灌注的初步实验研究

A primary study for dynamic susceptibility-contrast MR perfusion imaging using superparamagnetic iron oxide particles in normal brain of rabbits

目的探讨铁羧葡胺（Resovist）应用于脑MR灌注加权成像（PWI）的可行性、给药方法以及最佳剂量。方法健康新西兰大白兔30只，随机数字法平均分为A、B、C、D、E组。其中A、B、C、D4组分别给予4、8、16、32μmolFe／kg；E组设为对照，给予0．2mmol／kg的钆喷替酸葡甲胺（Gd-DTPA）。所有动物均行MR PWI，获得相应信号强度-时间曲线图，并分别计算脑灰质、白质的最大信号下降百分比（SRRmax）、局部脑血容量（rCBV）和灰质与白质rCBV之比（QrCBV）、SRRmax之比（QSRR max）。所得数据，根据资料性质，行配对t检验和单因素方差分析。结果Resovist能快速团注，4组均获得满意的信号强度-时间曲线图；4种剂量的Resovist对实验兔脑灰质和白质均有良好的分辨率。A、B、C、D、E5组脑灰质和白质的rCBV分别为（50．48±3．84）、（25．57±2．10），（94．69±2．60）、（45．33±3．14），（141．13±6．26）、（67．67±4．65），（243．75±5．90）、（162．06±5．14），（84.60±3、60）、（41.36±2．18）ml／100g；灰质和白质的SRRm,1分别为：（13．70±1．50）％、（7.38±0．41）％，（31．01±4．06）％、（16．49±2．35）％，（43．81±3．42）％、（21．64±4．14）％，（64．49±5．35）％、（43．61±5．78）％，（27．78±2．98）％、（14．42±2．25）％；各组脑灰质与白质检测数据比较差异均有统计学意义（P值均〈0．01）。A、B、C、D、E5组QrCBV分别为1．98±0．07、2．09±0．11、2．09±0．07、1．50±0．01、2．05±0．03；QSRRmax分别为：1．85±0．11、1．88±0．06、2．06±0．25、1．49±0．09、1．94±0．12；5组间差异均有统计学意义（QrCBV的F值为85．076，QSRR max的F值为13．915，P均〈0．01）。A、B、C3组QrCBV值和QSRR max值差异无统计学意义（P〉0．05）；而D组QrCBV值和QSRRmax值显著低于A组（P〈0．01）。结论Resovist应用于MR脑灌注是可行的，适宜剂量4—16μmolFe／kg。

Objective To study the feasibility of cerebral perfusion weighted imaging（PWI） using superparamagnetic iron oxide particles （SPIO） Resovist in normal rabbits, and investigate the methodology and the proper contrast agent dose of SPIO in PWI. Methods All 30 rabbits were randomly divide into 5 groups（n =6 for each）, group A, B,C,D were divided according to the different dose of Resovist （4, 8, 16 and 32 μmol Fe/kg） and group E was operated as control study with 0. 2 mmol/kg C,d-DTPA. The dynamic MR perfusion imaging series were acquired in each group. The signal intensity time curves were analyzed in gray matter and white matter, and the parameters （rCBV, SRRmax, QrCBV, QSRRmax ） were calculated and compared in all groups and correlated with control one. Results a bolus injection was succeed for all studies, and a dose-dependent strong reduction in signal intensity of gray and white matter in all groups was demonstrated. The rCBV values of gray and white matter for group A, B, C, D and E were （50.48 ± 3.84）,（25.57±2.10）; （94.69 ±2.60）, （45.33 ± 3.14）; （141.13±6.26）,（67.67± 4.65）; （243.75 ± 5.90）, （162.06 ± 5.14）; and （84.60 ± 3.60）, （41.36 ± 2.18） ml/100 g, respectively. The SRRmax values of gray and white matter for group A, B, C, D and E were （ 13. 70 ± 1.50）% ,（7. 38 ± 0.41 ）% ; （31.01 ± 4.06）%, （ 16.49 ± 2. 35 ）% ; （43.81 ± 3.42）%, （21.64 ± 4.14）%; （64.49 ± 5.35）%, （43.61 ± 5.78）%; and （27.78 ± 2.98）%, （14.42 ± 2.25）%; respectively. The QrCBV values for group A, B, C, D and E were 1. 98 ± 0. 07, 2. 09 ± 0. 11,2. 09 ± 0. 07,1.50 ±0. 01 ,and 2. 05 ±0. 03, respectively, and the QsRRmax values for group A, B,C,D and E were 1.85 ± 0. 11,1.88 ± 0.06,2. 06 ± 0. 25,1.49 ± 0. 09, and 1.94 ± 0. 12, respectively. All above values among group were significantly different （P 〈 0. 01 ）. For the QrCBV and QsRRmax values between group, there were no significant difference between group A and B, B and C, A and C; while the values of group A was significantly larger than those of group D （ P 〈 0. 01 ）. Conclusion Resovist （SPIO） can be used in the study of MR perfusion weighted imaging in the brain, and the proper contrast agent dose is 4-16μmol Fe/kg.