肥厚型心肌病^(18)F-FAPI PET/CT显像的初步探索:与心脏磁共振比较

Preliminary study of ^(18)F-FAPI PET/CT in hypertrophic cardiomyopathy: comparisonwith cardiac magnetic resonance imaging

目的探讨肥厚型心肌病(hypertrophic cardiomyopathy,HCM)患者^(18)F标记的成纤维细胞活化蛋白抑制剂(fibroblast activation protein inhibitor,FAPI)正电子发射型计算机断层扫描显像/电子计算机断层显像(positron emission tomography/computed tomography,PET/CT)显像特点,并与心脏磁共振(cardiac magnetic resonance,CMR)延迟强化(late gadolinium enhancement,LGE)技术比较,探讨两种检查方法的关系。方法前瞻性纳入经超声或CMR证实为HCM的患者22例,所有患者均行^(18)F-FAPI PET/CT和CMR,并于CMR检查时抽取静脉血行实验室检查。正常对照组纳入22名与HCM组年龄、性别相符的健康志愿者,仅行^(18)F-FAPI PET/CT。通过后处理软件获得HCM患者左心室心肌的最大标准摄取值(maximum standardized uptake value,SUV_(max))和最大靶本底比值(maximum target-to-background ratio,TBR_(max))。将^(18)F-FAPI摄于大于SUV_(max)值40%的心肌定义为摄取心肌,并通过CMR获得的左心室心肌体积计算摄取百分比,即FAPI%。CMR检查使用3.0 T磁共振扫描仪,通过后处理软件获得HCM患者的左心室室壁最大厚度和左心室心肌LGE百分比(LGE%)。使用独立样本t检验或Mann–Whitney U检验比较HCM患者和健康志愿者心肌^(18)F-FAPI摄取的差异,使用Pearson或Spearman相关性检验来比较^(18)F-FAPI PET/CT参数和CMR参数的相关性及与实验室检查的相关性。结果HCM患者的左心室心肌^(18)F-FAPI摄取明显高于健康志愿者(TBR_(max)中位数:8.96 vs 1.19,P<0.001)。HCM患者左心室心肌^(18)F-FAPI摄取的范围大于LGE的范围(FAPI%vs LGE%,中位数:73.77 vs 6.69,P<0.001)。^(18)F-FAPI摄取的范围和CMR测量的LGE范围、左室射血分数(left ventricular ejection fraction,LVEF)呈中等相关(FAPI%,LGE%and LVEF,r=0.67,-0.49,P<0.05)。同时,^(18)F-FAPI摄取的范围和血清N末端B型利钠肽原(N-terminal pro-B-type natriuretic peptide,NT-proBNP)和肌酸激酶同工酶(creatine kinase-MB,CK-MB)的水平呈中等相关(FAPI%,NT-proBNP and CK-MB,r=0.58,0.54,P<0.05)。CMR的参数和实验室检查无相关性。结论^(18)F-FAPI与CMR参数中等相关,^(18)F-FAPI PET/CT可以识别出更多的受累心肌。

Objective To explore the characteristics of ^(18)F-labeled fibroblast activation protein inhibitor(FAPI)positron emission tomography/computed tomography(PET/CT)in the patients with hypertrophic cardiomyopathy(HCM),as well as the correlation between ^(18)F-FAPI activity and cardiac magnetic resonance(CMR)late gadolinium enhancement(LGE)technique.Methods Twenty-two HCM patients were prospectively recruited in this study with ^(18)F-FAPI PET/CT examination,CMR examination and blood tests.A control group of twenty-two healthy participants with the same age and sex as the HCM group was also recruited and only underwent ^(18)F-FAPI PET/CT examination.The _(max)imum standardized uptake value(SUV _(max))and _(max)imum target-to-background ratio(TBR _(max))of left ventricular(LV)myocardium were then obtained by post-processing software.The region grow algorithm with a threshold of 40%of the SUV _(max) was set to determine the ^(18)F-FAPI volume.The ^(18)F-FAPI volume was further expressed as a percentage of LV volume derived from CMR,which was defined as the ^(18)F-FAPI extent(FAPI%).CMR examination was performed on a 3.0 Tesla scanner.The _(max)imum thickness and LGE extent(LGE%)of LV myocardium were then obtained by post-processing software.The independent-sample t test or Mann Whitney U test was used to evaluate the differences of ^(18)F-FAPI uptake between the patients with HCM and healthy participants.The correlation of ^(18)F-FAPI activity and CMR parameters were assessed by Pearson/Spearman’s correlation test.Results The myocardial ^(18)F-FAPI uptake of LV in patients with HCM was significantly higher than that in the healthy participants(TBR _(max),median:8.96 vs 1.19,P<0.001).In patients with HCM,the ^(18)F-FAPI extent was larger than LGE extent(FAPI%vs LGE%,median:73.77 vs 6.69,P<0.001),and moderate correlation was observed between ^(18)F-FAPI extent,LGE extent and LVEF(FAPI,LGE%and LVEF,r=0.67,-0.49,P<0.05).Moreover,moderate correlation was observed between ^(18)F-FAPI extent with N-terminal pro-B-type natriuretic peptide(NT-proBNP)and creatine kinase-MB(CK-MB)(FAPI%,NT-proBNP and CK-MB,r=0.58,0.54,P<0.05).No correlation was observed between CMR parameters and blood tests.Conclusion The measurement of ^(18)F-FAPI was moderately correlated with the CMR,and ^(18)F-FAPI PET/CT could detect a wider range of myocardium than CMR.