SPR Unknown #72 -- FINAL
Publication Date: 2012-07-03
16 year old male collapsed playing basketball
The right ventricle was of moderately increased size, RV EDV = 123 cc/m^2. There was no significant right ventricular hypertrophy. The basilar inferior, basilar anterolateral, mid-anterolateral, and mid-inferior segment showed evidence of macroscopic fatty infiltration and segmental replacement of the myocardium on black-blood imaging (small arrows). There was diastolic dilatation of the basilar anterolateral RV wall.
The left ventricle was of normal size, LV EDV = 78 cc/ m^2. There was no left ventricular hypertrophy. In the posterior apical-lateral segment of the left ventricular wall, a small area of fatty infiltration is present (arrowhead).
Arrhythmogenic right ventricular dysplasia (ARVD) is a genetic myocardial disease that predominantly affects the right ventricle. Diagnosis of ARVD is difficult due to non-specific clinical findings and presentation. MRI is used to assess morphological changes and functional abnormalities, including dilatation, myocardial thinning, fibro-fatty infiltration, and ventricular wall motion abnormalities. Morphological changes observed include dilatation of the right ventricle, common but non-specific, and myocardium thinning associated with aneurismal outpouchings during systole described in the literature as the “accordion sign”, a sensitive finding. Dysfunction of the right ventricle is the most specific and sensitive finding of ARVD, therefore, wall motion abnormalities on MRI are a reliable finding in the diagnosis of ARVD. Spin-echo black–blood imaging sequences can demonstrate fatty changes in the myocardium, but not considered specific or sensitive when identified as an isolated finding.
Interestingly, our patient demonstrated a small area of fatty change in the left ventricle. In most cases, fatty changes preferentially involve the right ventricle, but the genetic desmosomal mutation can also present with the involvement of the left ventricle, although less commonly observed. Following post-processing of the images, there was moderately decreased right ventricular systolic function, RV EF = 36%, with basilar inferior and basilar anterolateral regional wall motion abnormalities. There was normal left ventricular systolic function, LV EF = 57%, with no obvious wall motion abnormalities.
Echocardiography has been used to assess morphological abnormalities associated with ARVD but has found to be nonspecific and insensitive due to the limitation of the lack of spatial resolution needed to assess for fatty and fibrotic changes typically seen in the myocardium of the right ventricle. Echocardiograph was not obtained in our patient prior to his presentation to the ED.
- Yoo SJ, Grosse-Wartman L, Hamilton M. Magnetic Resonance Imaging Assessment of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia in Children. Korean Circ J 2012;40:357-267
- Kayser H, van der Wall E, Sivananthan M, et al. Diagnosis of Arrhythmogenic Right Ventricular Dysplasia: A Review. Radiographics 2002; 22:639-650