Left ventricular noncompaction: a proposal of new diagnostic criteria by multidetector computed tomography.

Background: Left ventricular noncompaction (LVNC) is a cardiomyopathy characterized by a noncompacted myocardial layer in the left ventricle, primarily diagnosed by echocardiographic and magnetic resonance criteria. Multidetector computed tomography (MDCT) is an imaging method that has been increasingly used in cardiac evaluation. However, tomographic criteria to diagnose LVNC have not been determined.

Objectives: We assessed the structural characteristics of LVNC with MDCT and proposed tomographic criteria that may differentiate LVNC from healthy subjects and patients with other cardiomyopathies that might be associated with increased myocardial trabeculation.

Methods: Between March 2007 and June 2009 we studied 10 consecutive patients with LVNC diagnosed by echocardiogram and/or magnetic resonance imaging who underwent electrocardiogram-gated coronary CT angiography. We evaluated the ratio of noncompacted to compacted myocardium (NC/C ratio) in end diastole in each of the 17 segments established by the American Heart Association (excluding the apex). The results were compared with 9 healthy subjects, 14 patients with hypertrophic cardiomyopathy, and 17 patients with dilated cardiomyopathy to determine the cutoff that would distinguish patients with LVNC.

Results: When considering involvement of more than 1 segment, the NC/C ratio of 2.2 distinguished pathologic noncompaction, with sensitivity and specificity of 100% and 95%, respectively. In addition, the involvement of ≥2 segments allows the distinction of all patients with LVNC from other cardiomyopathies and from healthy subjects.

Conclusions: LVNC can be accurately diagnosed with MDCT when using a cutoff NC/C ratio of 2.2 at end diastole involving ≥2 segments.