OBJECTIVETo characterize the clinical and cardiac MRI features of dilated cardiomyopathy (DCM) and left ventricular noncompaction (LVNC).

METHODSCompared the clinical and MRI features between 25 patients with LVNC and 21 patients with DCM. The MRI derived diastolic left ventricular wall thickness and the number and degree of noncompaction (NC) were evaluated using the 17-segment model.

RESULTSChest distress, shortness of breath and abnormal ECG were presented in all DCM patients, abnormal ECG was evidenced in 22 LVNC patients and 21 out of 25 LVNC patients presented similar clinical symptoms as DCM patients while the rest 4 LVNC patients were asymptomatic. Left atrial and ventricular dimensions were significantly smaller in LVNC patients compared to DCM patients. The degree of left ventricular (LV) spherical remodeling was significantly greater in patients with DCM (sphericity index, SI = 0.81 +/- 0.06) than in patients with LVNC (SI = 0.74 +/- 0.11, P < 0.05). The LV ejection fraction (LVEF) was significantly higher in patients with LVNC (32.7% +/- 14.2%) than that in patients with DCM (15.0% +/- 5.1%). The number of NC segments in LVNC patients (9 +/- 1) was significantly higher than the number of hypertrabeculation segment in DCM patients (5 +/- 2). The left ventricular apex (the 17th segment) was unexceptionally involved in all LVNC patients, while hypertrabeculation was absent in the 17th segment of DCM patients. The NC was more common in the apical and mid segments (16th, 12th and 11th segments) than in basal and mid septal segments (2nd, 3rd, 8th and 9th segments) in both LVNC and DCM patients. The thickness of compacted myocardium of the segments associated with noncompaction appeared thin in two groups. The wall thickness of noncompaction myocardium segments was thicker in LVNC patients than in DCM patients. The end-diastolic NC/C ratio was, on average, higher in patients with LVNC (3.3 +/- 0.6) than in patients with DCM (1.9 +/- 0.3).

CONCLUSIONSThe clinical manifestation is similar while there are significant differences in the morphology and function of left atria and left ventricle between the LVNC and DCM patients. The different distribution and degree of NC were helpful to differentiate LVNC from DCM.