Table 1.

Examples of Echocardiographic and CMR Approaches to Determining the Extent of LV Trabeculations

	Jenni et al3	Petersen et al17	Jacquier et al105	Stacey et al139	Captur et al140
Modality	Echocardiography	CMR	CMR	CMR	CMR
Sample size	Noncompaction (n = 34) No control group	Noncompaction (n = 7) Control subjects (n = 170)	Noncompaction (n = 16) Control subjects (n = 48)	Noncompaction (n = 122) No control group	Noncompaction (n = 30) Control subjects (n = 105)
Study design/external validation	Retrospective/no external validation cohort	Retrospective/no external validation cohort	Retrospective/no external validation cohort	Retrospective/no external validation cohort	Retrospective/no external validation cohort
Definition of noncompaction	Absence of coexisting cardiac disease Numerous excessively prominent trabeculations and deep intertrabecular recesses Intertrabecular spaces filled by direct blood flow from the ventricular cavity, on color Doppler imaging	Bilayered appearance on echocardiography combined with increased pretest probability (eg, similar appearance in first-degree relatives, associated neuromuscular disorder, or complications, such as systemic embolization and regional wall motion abnormalities)	Diagnosis of noncompaction was established on echocardiographic criteria	Consecutive patients from CMR reports that mention trabeculation or noncompaction	Diagnosis of noncompaction on echocardiographic criteria and at least 1 of the following: positive family history, associated neuromuscular disorder, regional wall motion abnormality, noncompaction-related complications (arrhythmia, heart failure, or thromboembolism)
Description	Noncompaction to compaction ratio Decreased thickening and hypokinesia present within, but not limited to, the noncompacted segments	Two-layered myocardium Measured at the most pronounced trabeculations, avoiding apex Measurement perpendicular to compact myocardium	Short-axis cines for total LV mass and compact mass to define trabecular mass Papillary muscle included in the myocardial mass	Apical short-axis views 16-24 mm from the true apical slice Region with the largest noncompaction to compaction ratio	Loss of base-to-apex fractional dimension gradient
Cardiac phase	End-systole	End-diastole	End-diastole	End-systole	End-diastole
Cardiac view	Short axis	Long axes (4-chamber, 2-chamber, 3-chamber)	Short-axis stack	Apical short axis	Short-axis stack
Excessive trabeculation cutoff	Noncompaction to compaction ratio >2	Noncompaction to compaction ratio >2.3	Trabecular mass >20%	Noncompaction to compaction ratio ≥2	Fractal dimension ≥1.30

These definitions highlight variation in current definitions of excessive trabeculation. Because imaging studies are typically needed to define disease presence without other independent standard of reference, inclusion bias is typically present in such studies. Note that “noncompaction” refers to terms in the original references, rather than the more contemporary description of excessive trabeculation.

CMR = cardiac magnetic resonance; LV = left ventricular.