Yoo Jin Hong MD, Abstract Co-Author: Nothing to Disclose

Donghyun Hong MS, Abstract Co-Author: Nothing to Disclose

Chul hwan Park MD, Presenter: Nothing to Disclose

Byoung Wook Choi MD, Abstract Co-Author: Nothing to Disclose

To examine the change of myocardial extracellular volume (ECV) fraction using contrast enhanced magnetic resonance imaging in rabbit during the dilated cardiomyopathy modeling and to investigate the correlation between ECV and the degree of fibrosis and electron microscopic findings in dilated cardiomyopathy rabbit (DCR) models.

DCR (male adult New Zealand White rabbit, 3−4 kg) models were made by injecting doxorubicin (Doxorubicin Hydrochloride, Cayman) with doses of 1.0mg/kg twice a week for maxi16weeks. Every rabbit underwent cardiac MRI pre- and post- T1 mapping using modified Look-Locker inversion recovery (MOLLI) sequence, LGE, and cine MRI on a clinical 3-T cardiac magnetic resonance (CMR) system before drug administration (Control group) and at 6th , 12th , and 16th week after drug administration (DCR modeling) On MRI, ECV was calculated at the septum using the myocardial pre, post T1 value, LV blood pool T1 value, and hematocrit(Hct) as follows: ECV = [(1/T1post-contrast myocardium)-(1/T1pre-contrast myocardium)/(1/T1post-contrast blood)-(1/T1pre-contrast blood)] × (1-Hct). Fibrosis was quantitatively measured by image J (V. 1.47, NIH, Bethesda, MA) with digital images of specimens stained with picrosirius red. For electron microscopic findings, specimens were obtained at interventricular septum and lateral wall.  

Three pre-model and fifteen post-models (five: 6–week, three; 12-week, seven; 16week models) were included. The mean ECV values significantly increased from the 6th week (pre vs. 6th week vs. 12th week vs. 16th week; 29.4±2.0 vs. 31.8±3.4 vs. 36.1±5.4 vs. 40.1±4.1, p-value<0.05). There was a good correlation between myocardial ECV measured by cardiac MRI and the degree of fibrosis (r=0.75, p-value<0.001). On electron microscopy, myocyte hypertrophy, mitochondrial swelling, pleomorphism and Z band disruption were noted. Collage bundle and strands were significantly increased in extracelluar space in 12 and 16 week model specimens.  

The ECV measured by contrast enhanced MRI in DCR models significantly increased from 6th week and ECV showed good correlation with histologic fibrosis.    

MR ECV is a noninvasive useful method for a quantification of diffuse myocardial fibrosis which can replace endomyocardial biopsy.  

Hong, Y, Hong, D, Park, C, Choi, B, The Cumulative Effect of Doxorubicin on the Change of Myocardial Extracellular Volume Fraction Measured by Contrast Enhanced Magnetic Resonance Imaging in Dilated Cardiomyopathy Rabbit Models; Histopathology Analysis and Electron Microscopic Findings.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14016635.html