Marginal Incremental Benefit of Late Gadolinium Enhancement Imaging by MRI in the Screening of Referrals for Arrhythmogenic Right Ventricular Cardiomyopathy

Objective: To investigate the additional clinical utility of routinely incorporating post-gadolinium inversion recovery sequences into a standard clinical MRI protocol for assessment of possible arrhythmogenic right ventricular cardiomyopathy (ARVC).

Materials and Methods: Retrospective review of all patients referred to the Cardiac MRI department of Toronto General Hospital for the assessment of possible ARVD between January 2005 and April 2009. Data on reason for referral, patient demographics, left and right ventricular (RV) size and ejection fraction were abstracted from the clinical report. Presence or absence of regional wall motion abnormalities and/or late gadolinium enhancement were noted in each case. Likelihood of ARVC based on the imaging appearances and supplied clinical information was classified by a single abstractor as: very likely, possible, unlikely, or alternate diagnosis.

Results: Three hundred fifty seven patients underwent post-gadolinium inversion recovery imaging in a minimum of the axial and short axis planes. Mean patient age was 46 years (SD 15 years). Of the 357 patients who received gadolinium, only 10 (3%) had evidence of late gadolinium enhancement (LGE) in the RV and in only three of these cases (0.84%) was the diagnosis thought likely to be ARVC. Other causes of RV LGE included: myocarditis, postablation therapy, and post right coronary angioplasty. The presence of LGE in the RV was associated with larger end-diastolic volume (116 ± 55 mL vs 87 ± 22 mL, p < 0.0003) and lower EF (45 ± 12% vs 53 ± 7% p < 0.003) compared to those patients without LGE. LV LGE was seen in 16 of 357 patients (5%) receiving gadolinium. Those with LGE had significantly larger EDV (97 ± 30 mL vs 82 ± 19 mL, p < 0.004) and lower EF (47 ± 14% vs 57 ± 9%). Diagnoses in the LV LGE positive group were: myocarditis, dilated cardiomyopathy, hypertrophic cardiomyopathy, sarcoidosis, ischemic, and unknown.

Conclusion: There was a low yield from post-gadolinium imaging in this study. Likely ARVC cases with positive RV LGE had significant RV volumetric or wall motion abnormalities already highly suggestive of ARVC. LGE sequences add only marginal diagnostic benefit and may safely be omitted as part of a routine cardiac MR workup for `query ARVC'.