肥厚型心肌病(hypertrophic cardiomyopathy, HCM)是一遺傳性心肌病，其特徵是左心室肥厚(left ventricular hypertrophy, LVH)。LVH可由某些病因所引起，如高血壓、主動脈瓣狹窄或瀰漫性心肌纖維化(diffuse myocardial fibrosis, DMF)。過去的研究已證實心血管磁振造影(cardiovascular magnetic resonance imaging, CMR)的細胞外體積分率(extracellular volume fraction, ECV)可用來定量心肌的DMF嚴重程度。本研究目的主要是探討HCM病患的心室肥厚是否與患者心肌的DMF嚴重程度有關。本研究回顧性收集了125位臨床確診的HCM患者及58位臨床上無心肌結構異常的Brugada症候群受試者為控制組。使用造影劑前後的T1 Mapping和Cine圖像來評估心肌的DMF嚴重程度和相對應的心肌壁厚。分別測量心肌四個不同區域(包括前區、中膈區、後區和側面區)的ECV和厚度，使用Mann-Whitney U檢驗分析HCM和控制組其各區域的DMF與厚度之間的比較。並利用spearman相關係數來評估DMF與厚度間的關聯性。統計檢驗是兩尾的，統計學意義定義為p<0.05。結果發現，HCM患者的心肌壁厚顯著高於控制組(11.3 ±5.1 mm對6.0 ±2.2 mm，p<0.001)。細胞外體積分率也高於控制組(27.5 ±4.9％對25.0 ±2.3％，p<0.001)。在關聯性分析方面，細胞外體積分率與左心室壁厚呈現具統計意義的正相關性(r =0.46，p<0.001)。從研究結果顯示，認為HCM患者的左心室心肌厚度的確有明顯的增加，而增加之程度可能與其心肌組織內的瀰漫性纖維化嚴重程度是有關的。因此，利用CMR可以用來評估HCM病患者其DMF的進展，提供臨床醫師進行早期診療的參考，避免進一步惡化影響病患心臟功能。

Hypertrophic cardiomyopathy (HCM) is hereditary cardiomyopathy that is characterized by left ventricular hypertrophy (LVH). LVH can develop in response to some factors, such as hypertension, aortic stenosis, or diffuse myocardial fibrosis (DMF). Cardiovascular magnetic resonance (CMR) has been widely used to quantify DMF by calculating the extracellular volume fraction (ECV) of the myocardium. Our aim was to investigate whether the severity of ventricular hypertrophy is associated with the degree of DMF in patients with HCM. Patients with HCM (n=125) and Brugada syndrome which was considered as the relative normal heart control (n=58) were retrospectively enrolled in this study. Pre- and postcontrast T1 maps and Cine images were acquired at 1.5T for the assessment of ECV and wall thickness (WT). ECV and WT measurements at 4 different regions, including the anterior, septal, posterior, and lateral wall regions, were measured, and all groups were compared. Regional ECV was correlated with the corresponding regional WT. Group comparison between two groups in ECV and WT were analyzed with the Mann-Whitney U test. Spearman was used to obtain a correlation coefficient between regional ECV and WT. The statistical tests were two-tailed, and statistical significance was defined as p < 0.05.For the group comparison, HCM patients showed a significantly higher WT compared to that in controls (11.3±5.1 mm vs. 6.0±2.2 mm, p<0.001). In addition, HCM patients also revealed significantly higher ECV compared to that in controls (27.5±4.9% vs. 25.0±2.3%, p<0.001). The average ECV was significantly correlated with the average WT in patients with HCM (r=0.46, p<0.001). In this study, we demonstrated that HCM patients with higher WT compared with controls. This finding supports that HCM patients have significant LVH. The increased ECV was positively associated with the corresponding regional wall thickness. This finding suggests that the severity of LVH might be associated with the degree of DMF in patients with HCM.