Cardiac Mri in Cardiomyopathies

Figures & data

Figure 1. Flow diagram illustrating notable causative factors of dilated cardiomyopathy.

Figure 2. Difference in cardiac pathology between hypertrophic cardiomyopathy and dilated cardiomyopathy.

Created with Biorender.com.

Figure 3. Hypertrophic versus dilated cardiomyopathy.

Left: two-chamber delayed gadolinium enhancement imaging showing apical hypertrophic cardiomyopathy with diffuse mid-wall fibrosis in the hypertrophied segments. Right: Four-chamber SSFP imaging showing the typical appearance of dilated cardiomyopathy-related ventricular thinning.

Table 1. Adapted table illustrating the results from Halliday and colleagues showing the respective hazard ratios for risk of all-cause mortality, and a composite of sudden cardiac death and aborted sudden cardiac death, for extent, pattern and location of late gadolinium enhancement.

LGE	Adjusted hazard ratio
	All-cause mortality	SCD + aborted SCD
Extent of LGE as a percentage of total myocardial mass:
0–2.55%	1.59	2.79
2.55–5.10%	1.56	3.86
>5.10%	2.31	4.87
Pattern of LGE:
Linear mid-wall	1.70	3.21
Sub-epicardial	1.29	5.54
Focal	2.85	3.16
Multiple patterns of enhancement	2.00	5.72
Location of LGE:
Septum only	1.96	3.13
LV free-wall only	0.77	-
Septum + LV free-wall	1.99	5.82

LGE: Late gadolinium enhancement; LV: Left ventricle; SCD: Sudden cardiac death.

Data taken with permission from [30].

Figure 4. Delayed enhancement image demonstrating mid-wall fibrosis in a dilated cardiomyopathy.

Table 2. Summary of the various roles of cardiac MRI in dilated cardiomyopathy.

CMR sequence	Relevant findings in DCM
Ejection fraction measurement	• A mean difference in EF measurement between TTE and CMR of 4%   • LVEF as measured by CMR being more predictive of mortality   • The choice of imaging technique for EF could result in the reclassification of a significant number of patients for life-saving ICD implantation
Late gadolinium enhancement	• LGE occurs in approximately 30% of patients   • Different patterns and locations of LGE are associated with both different risks of adverse events and different etiological subsets of DCM   • Not a purely binary measurement as variances in intensity of LGE can be predictive of variances in outcome
Extracellular volume fraction	• More accurate than LGE in imaging diffuse fibrosis, with increased predictive value for major adverse events, such as death or hospitalization   • Increased percentage of ECV correlated with increased risk of adverse events   • Similar to LGE, the location of ECV had a predictive role   • Can be combined with LVEF to increase predictive value
T1 sequences	• T1 mapping shown to be most predictive factor in differentiating cause of initial LV dilatation, i.e., athlete’s heart or the initial stages of DCM in comparison to T2 mapping or ECV measurements   • Can be used in other organ systems, such as the liver, to track development of DCM to heart failure

CMR: Cardiac MRI; DCM; Dilated cardiomyopathy; ECV: Extracellular volume fraction; EF: Ejection fraction; ICD: Implanted cardioverter defibrillator; LGE: Late gadolinium enhancement; LV: Left ventricle; LVEF: Left ventricular ejection fraction; TTE; Transthoracic echocardiography.

Figure 5. An illustration of ventricular wall thickening and areas of fibrosis in a heart with hypertrophic cardiomyopathy.

Table 3. Summary of the various roles of cardiac magnetic resonance imaging in hypertrophic cardiomyopathy.

CMR sequence	Relevant findings in HCM
Diagnostic potential	• CMR can more easily differentiate different causes of LVH, i.e., HCM vs hypertensive cardiomyopathy
LGE	• Lack of correlation between presence of LGE and outcomes in HCM
T1 mapping and ECV measurements	• Small scale studies have shown that ECV maps have predictive value for adverse outcomes   • Needs to be tested in larger, multi-center trials
T2 mapping	• T2-weighted CMR can provide both pathophysiological insights to the progression of HCM   • High intensity signals on T2-weighted images have been shown to correlate with troponin T levels and hypothesized to be a marker of myocardial injury in HCM patients

CMR: Cardiac MRI; ECV: Extracellular volume fraction; HCM; Hypertrophic cardiomyopathy; LGE: Late gadolinium enhancement; LVH: Left ventricular hypertrophy.

Halliday BP , BaksiAJ, GulatiAet al. Outcome in dilated cardiomyopathy related to the extent, location, and pattern of late gadolinium enhancement. JACC Cardiovasc. Imaging, 12(8 Pt 2), 1645–1655 (2019).

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