CAJ | 학술논문

目的初步探讨MRI有效横向弛豫时间图(T2* map)序列对兔心肌铁超负荷模型心肌铁负荷定量评价的可行性.方法日本长耳兔11只,分为心肌铁超负荷组(10只)和正常对照组(1只).采用兔大腿深部肌内注射50 mg/kg右旋糖酐铁剂,制作心肌铁超负荷模型,注射12周.于注射铁剂前、注射铁剂后l～12周每周分别行血清铁和MR检查,MR扫描序列包括心脏短轴面和肝脏横轴面的T2* map序列,并测量心脏和肝脏的T2*和弛豫效率(R2*)值.于注射铁剂前、注射铁剂后1～8、11、12周的MR扫描完成后分别处死1只动物,剥离心脏和肝脏标本,进行离体MR扫描,扫描序列和测量方法同在体心脏和肝脏.MR扫描完成后切取左心室中间段心肌和部分肝组织进行石蜡包埋及普鲁士蓝染色.Pearson相关分析用于评价各测量参数之间的关系.结果心肌T2*[(32.5±8.3)ms]、R2*值[(38.4±7.9)Hz]与注入铁含量[(1 033.2±673.4) mg]呈显著线性相关(r值分别为-0.799和0.770,P值分别为0.001和0.002).心肌T2*值与肝脏T2*值无显著相关性(r=0.566,P=0.070).在体心脏和肝脏T2*值分别为(32.5±8.3)和(8.8 ±5.4)ms,与离体心脏和肝脏T2*值[(19.4±6.5)和(9.8±5.0)ms]相关性均强(r =0.757,P=0.007和r=0.861,P=0.001).在体与离体心脏和肝脏的T2*和R2*值与血清铁相关性均无统计学意义(P值均＞0.05).随着注入铁含量的增加,心肌内蓝染颗粒逐渐增多；肝窦和肝细胞内蓝染颗粒显著增加.结论 MRI的T2* map无创定量心肌铁负荷是可行的,可以为临床铁超负荷患者早期检出心肌铁超负荷提供可靠依据.
목적 초보탐토MRI유효횡향이예시간도(T2* map)서렬대토심기철초부하모형심기철부하정량평개적가행성.방법 일본장이토11지,분위심기철초부하조(10지)화정상대조조(1지).채용토대퇴심부기내주사50 mg/kg우선당항철제,제작심기철초부하모형,주사12주.우주사철제전、주사철제후l～12주매주분별행혈청철화MR검사,MR소묘서렬포괄심장단축면화간장횡축면적T2* map서렬,병측량심장화간장적T2*화이예효솔(R2*)치.우주사철제전、주사철제후1～8、11、12주적MR소묘완성후분별처사1지동물,박리심장화간장표본,진행리체MR소묘,소묘서렬화측량방법동재체심장화간장.MR소묘완성후절취좌심실중간단심기화부분간조직진행석사포매급보로사람염색.Pearson상관분석용우평개각측량삼수지간적관계.결과 심기T2*[(32.5±8.3)ms]、R2*치[(38.4±7.9)Hz]여주입철함량[(1 033.2±673.4) mg]정현저선성상관(r치분별위-0.799화0.770,P치분별위0.001화0.002).심기T2*치여간장T2*치무현저상관성(r=0.566,P=0.070).재체심장화간장T2*치분별위(32.5±8.3)화(8.8 ±5.4)ms,여리체심장화간장T2*치[(19.4±6.5)화(9.8±5.0)ms]상관성균강(r =0.757,P=0.007화r=0.861,P=0.001).재체여리체심장화간장적T2*화R2*치여혈청철상관성균무통계학의의(P치균＞0.05).수착주입철함량적증가,심기내람염과립축점증다；간두화간세포내람염과립현저증가.결론 MRI적T2* map무창정량심기철부하시가행적,가이위림상철초부하환자조기검출심기철초부하제공가고의거.
Objective To preliminarily investigate the feasibility of MRI-T2* map in evaluating myocardial iron load of myocardial iron overload rabbit models.Methods Eleven rabbits were included in this study and divided into two groups,myocardial iron overload group (n =10) and the control group (n =1).Iron dextrin (dose of 50 mg/kg) was injected in muscles of thigh once a week,totally 12 weeks.Serum iron test and MRI examination were performed before iron injection,and 1 week to 12 weeks after iron injection.MRI scan protocol included short axial T2* map of the left ventricle and cross-section T2* map of the liver.T2* and R2* of the heart and the liver were measured.One rabbit was killed after MRI examination at pre-iron injection,1 week to 8 weeks,11 weeks and 12 weeks after iron injection,respectively.Heart and liver were avulsed to undergo in vitro MRI scan and then paraffin embedded for pathological slices.MRI scan protocol and measurements of the heart and the liver samples were the same to that of in vivo ones.Pearson correlation was used to calculate the relationships between the parameters.Results Myocardial T2* [(32.5 ± 8.3 ms)] and R2* values [(38.4 ± 7.9) Hz] had significant correlation with injecting iron content(1 033.2 ± 673.4 mg),the Pearson coefficients were-0.799 (P =0.001) and 0.770 (P =0.002),respectively.Myocardial T2 had no significant correlation with liver T2* values (r =0.556,P =0.070).T2* values of heart and liver in vivo [(32.5 ± 8.3) ms and (8.8 ± 5.4) ms],respectively had strong correlation with those in vitro [(19.4 ± 6.5) ms and (9.8 ± 5.0) ms],respectively (r =0.757,P =0.007 and r=0.861,P=0.001).T2* and R2* values of the heart and the liver in vivo and in vitro had no significant correlations with serum iron (P ＞ 0.05).On Prussian blue staining slices,blue particles of myocardium,sinus hepaticus and hepatocyte increased with injecting iron content.Conclusions It is feasible for MRI-T2* map to evaluate the myocardial iron load noninvasively.It may provide reliable information for detecting myocardial iron overload in patients with iron overload at an early stage.