3D Evaluation of Myocardial Edema: Experimental Study on 22 Pigs Using Magnetic Resonance and Tissue Analysis*

Background: Myocardial edema (ME) adversely affects ventricular function. Thus, we performed an animal study to demonstrate (1) 3D-ME using magnetic resonance imaging (MRI), which can show ME depending on myocardial location, (2) type of cardioplegic solution, and (3) quantification tools. Methods: Pig hearts (n = 22) were perfused using Bretschneider's solution (BRET, n = 8), butanedionemonoxime (BDM, n=8), or no cardioplegia as controls (CTRL, n = 6). Hearts underwent MRI (T₁-inversion recovery). Myocardial water content (MWC, reference method) was determined from left ventricle anterior, posterior (PW), lateral wall, interventricular septum, papillary muscle, right ventricle wall. Images underwent 3D reconstruction using ray-tracing. Gray-value analysis was performed on „virtual” samples. For statistical analysis, ANOVA, Student's t-test, and the Student-Newman-Keuls test were used. Results: (1) ME was induced (p < 0.0001 vs. control). Localization differed in MWC, p = 0.003 (BRET), p = 0.023 (BDM), highest at PW (p < 0.01). (2) Differences between the cardioplegia groups were not significant. (3) “Virtual” samples showed equal distribution (BRET: p = 0.007, BDM: p = 0.003), highest at PW (p < 0.01). Conclusions: We validated 3D assessment of induced ME in pig hearts using MRI. The method may therefore become an exact tool in monitoring cardioplegia.

Key words:

Myocardial edema - Magnetic resonance tomography - Tissue analysis - Myocardial perfusion - Cardioplegia

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*This paper was presented at the 3^rd joint meeting of the German, the Austrian and the Swiss Societies for Thoracic and Cardiovascular Surgery, February 9 - 12, Lucerne (P 194, Thorac Cardiovasc Surg 2000, 48 Suppl 1: 145).