Table 1 Summary of most common differential diagnosis of HCM phenotypes
From: Differential diagnosis of thickened myocardium: an illustrative MRI review
Myocardial thickening | Differential diagnosis | Characteristics | MRI clues suggesting HCM |
|---|---|---|---|
Concentric | Athlete’s heart | Mild wall hypertrophy Increased ventricular volume Normal diastolic function Absence of LGE Detraining can regress the hypertrophy and ventricular volume | Asymmetric wall hypertrophy Small/normal ventricular size Diastolic LV dysfunction LGE can be present |
HHS | Mild wall hypertrophy Elevated indexed LV mass Increased ventricular volume Uncommon mid-wall LGE Regression of LV hypertrophy after systolic blood pressure control | Asymmetric wall hypertrophy Normal indexed LV mass Small/normal ventricular size Patchy LGE most common | |
Aortic stenosis | Mild/moderate wall hypertrophy Turbulent flow jet across aortic valve Diffuse subendocardial or mid-wall LGE | Normal aortic root and valve Subaortic turbulent flow jet in obstructive HCM Patchy and extensive LGE most common | |
Cardiac amyloidosis | Marked wall thickness Dilatation of both atria Thickening of atrial free wall, interatrial septum and valves Difficult to find the optimal inversion time for nulling the normal myocardium Diffuse, subendocardial or transmural LGE | Asymmetric wall thickness Left atrial dilatation Spared atrial wall, interatrial septum and valves Endocardial LGE is rare | |
Asymmetric | Cardiac sarcoidosis | Basal septal thinning Aneurysms and ventricular dysfunction Myocardial oedema at T2-w T2 mapping: early detection and follow-up during treatment Basal septal and lateral epicardial LGE | Myocardial oedema at T2-w is uncommon Patchy mid-wall or RV insertion points of ventricular septum LGE |
Apical | Mural thrombus | Delayed-enhancement image: very dark thrombus Subendocardial LGE | Delayed-enhancement image: greyish myocardium Patchy mid-wall or RV insertion points of ventricular septum LGE |
LV non-compaction | Apical and mid-wall trabeculations with spared of interventricular septum Non-compacted end-diastolic thickness > 2.3 compacted thickness Cine SSFP images: high signal intensity of intertrabecular recess | Apical myocardial thickening Cine SSFP images: endocardial smooth surface | |
Endomyocardial disease | Obliteration of the apical cavity Mural thrombus Subendocardial and triple-layered LGE | Apical myocardial thickening Patchy mid-wall LGE |