左心室心肌致密化不全的MRI诊断及与过度小梁化的鉴别诊断

目的 探讨MRI对左心室心肌致密化不全(LVNC)的诊断及与过度小梁化的鉴别诊断价值.方法 利用心脏MR检查,采用不同成像序列对25例LVNC、39例扩张型心肌病(DCM)、16例主动脉瓣狭窄(AS)、15例主动脉瓣关闭不全(AR)、19例高血压患者(HT)和22名正常人进行扫描,将左心室划分为17节段,采用方差分析对左心房及心室径线、左心功能及小梁化节段数目、程度进行统计学分析.结果 心脏MRI显示LVNC患者小梁化的节段最多为(10±2)段.所有LVNC患者的心尖段(第17节段)均受累,而其他组心尖段很少受累;其他易受累节段在所有受检者中分布大致相似,即侧壁中远段(第16、12、11节段)是最常见的受累节段,而室间隔近中段(第2、3、8、9节段)均未见受累.致密化不全心肌厚度与致密化心肌厚度比值(NC/C)在LVNC患者最高(3.3±0.6),与其他各组(AS:1.0±0.3,AR:1.0±O.3,HT:0.8±0.1,正常人:0.9±0.2)差异有统计学意义(F=169.62,P<0.05).通过ROC曲线分析,左心室舒张期NC/C比值>2.5能够鉴别LVNC与DCM,其敏感性为96.O%(24/25),特异性为94.9%(37/39).在25例LVNC患者中NC/C比值>2.5的节段数为4.0 ±2.0,而39例DCM患者中仅8例患者各有1个节段NC/C比值>2.5.结论 MRI是诊断LVNC和鉴别过度小梁化的一个理想方法,诊断LVNC应满足左心室心尖段明显呈致密化不全改变及游离壁中2个或2个以上节段舒张期NC/C比值>2.5.

Diagnosing left ventricular noncompaction by cardiac MRI and its differential diagnosis on left ventricular hypertrabeculation

Objective To define the diagnostic criteria of cardiovascular magnetic resonance imaging in distinguishing isolated left ventricular noncompaction (LVNC) from lesser degrees of hypertrabeculation. Methods Twenty-five patients with LVNC, 39 with dilated cardiomyopathy ( DCM), 16 with aortic stenosis(AS), 15 with aortic regurgitation(AR) , 19 with hypertension (HT) and 22 normal subjects were enrolled in this study. Cardiac magnetic resonance imaging was performed to evaluate the left chamber diameter, functional parameters and noncompaction or hypertrabeculation of the left ventricle in diastole with one-way ANOVA. The left ventricle was divided into 17 segments for localizing all involved segments in this present study. Results The LVNC patients had the commonest myocardial segments involved (10±2)in all subjects. Each patient with LVNC was unexceptionally associated with apical noncompaction (17th segment) , which was seldom found in the other subjects. The lateral walls including 16th, 12th and 11th segments were the most vulnerable segments in all subjects, but nobody was found to involve the basal and mid septum including 2nd, 3rd, 8th and 9th segments. The end-diastolic NC/C (noncompaction/compaction) ratio was, on average, the greatest in patients with LVNC (3.3±0.6), compared with all other subjects(AS:1.0 ±0.3, AR:1.0 ±0.3,HT:0.8 ±0.1,healthy volunteers:0.9 ±0. 2) (F = 169. 62,P <0.05). Receiver operating characteristics analysis identified the end-diastolic NC/C ratio of>2.5 as a valuable parameter to distinguish LVNC from DCM.with values for sensitivity of 96.O%(24/25)and specificity of 94.9%(37/39),respectively.The mean number of NC/C ratio>2.5 segments in the LVNC patients was 4.0 ±2.0.while 8 of 39 patients with DCM had only one segment of NC/C ratio >2.5.Conclusions MRI is all exceUent imaging modality to diagnose LVNC and distinguish LIVNC from hypertrabeeulation.The criteria of LVNC is the NC/C ratio>2.5 in two or more than two segments of free ventricular walls associated with the left ventrieular apex involved.