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Experimental Studies |
1 From the Physikalisches Institut (EP5) (M.N., K.H.H., A.H.) and Medizinische Universitätsklinik (K.H., C.W., R.K., G.E., W.R.B.), Universität Würzburg, Josef Schneider-Strasse 2, 97080 Würzburg, Germany; and Medizinisches Laserzentrum Lübeck, Germany (D.T., R.B.). Received August 6, 2001; revision requested September 24; final revision received March 18, 2002; accepted April 1. Supported by Sonderforschungsbereich 355 Herzinsuffizienz and Graduiertenkolleg HA 1232/8-1. Address correspondence to W.R.B. (e-mail: w.bauer@medizin.uni-wuerzburg.de).
PURPOSE: To monitor perfusion changes in remote myocardium caused by transmyocardial laser revascularization (TMLR) and to investigate the influence of TMLR on left ventricular morphology and function.
MATERIALS AND METHODS: The coronary arteries were ligated in 32 Wistar rats. Eight weeks later, cine magnetic resonance (MR) imaging was performed in both the treatment (n = 12) and control group (n = 8). TMLR was then performed in the remote myocardium in the treated group. Twelve weeks after myocardial infarction, cine MR imaging, including dobutamine-induced (10 µg per kilogram of body weight per minute via the tail vein) stress, was repeated and followed with hemodynamic measurements in both groups and with perfusion MR imaging (in-plane resolution, 140 x 140 µm) of the isolated heart at rest and during nitroglycerin-induced stress in the TMLR group (n = 10).
RESULTS: Left ventricular dilatation and hypertrophy were enhanced in the TMLR group (change in end-diastolic volume at 812 weeks: control group, 24.6 µL ± 16.7 and TMLR group, 81.7 µL ± 15.7; change in left ventricular mass: control group, 54.5 mg ± 19.2 and TMLR group, 124.1 mg ± 30.7; P < .03 for both). Ejection fractions at rest were approximately equal (control group, 40% ± 2; TMLR group, 38% ± 2; P value not significant), but during dobutamine-induced stress, the ejection fraction was higher in the TMLR group (54.4% ± 4.9; control group, 47.4% ± 4.8; P < .05). TMLR-treated areas were better perfused than was untreated myocardium (difference in perfusion: TMLR-treated vs control region, 3.89 mL/min/g ± 0.83 at rest vs 2.29 mL/min/g ± 1.06 during nitroglycerin-induced stress; P < .05 for both). Hemodynamic measurements revealed no differences between groups.
CONCLUSION: High-spatial-resolution perfusion MR imaging depicted a significant perfusion improvement after TMLR. Postmyocardial infarction remodeling of the left ventricle was found to be enhanced.
© RSNA, 2002
Index terms: Animals Experimental study Heart, experimental studies, 511.129 Heart, MR, 51.121412 Heart, perfusion Lasers Myocardium, infarction, 511.771
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