DOI: 10.1148/radiol.2352031760
MR-guided Percutaneous Intramyocardial Injection with an MR-compatible Catheter: Feasibility and Changes in T1 Values after Injection of Extracellular Contrast Medium in Pigs1
Gabriele A. Krombach, MD,
Joachim G. Pfeffer,
Sylvia Kinzel, DVM,
Markus Katoh, MD,
Rolf W. Günther, MD and
Arno Buecker, MD
1 From the Departments of Diagnostic Radiology (G.A.K., J.G.P., M.K., R.W.G., A.B.) and Experimental Veterinary Medicine (S.K.), University Hospital of the University of Technology, Pauwelstrasse 30, 52057 Aachen, Germany. Received October 31, 2003; revision requested January 26, 2004; final revision received July 9; accepted August 17. Address correspondence to G.A.K. (e-mail: krombach@rad.rwth-aachen.de)
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Figure 1. Radial steady-state free precession MR images (2.5/1.2; flip angle, 45°; temporal resolution, 66 msec per image) obtained with a long-axis view of the left ventricle. Top row: Catheter is clearly visible as a dark structure (arrow) with a small artifact arising from its tip. Bottom row: The catheter was advanced into the left ventricle (left), while still inside the introducer sheath, and then inserted into the myocardium (arrow). During injection of gadodiamide solution (right), there was a growing area of high signal intensity (arrow) within the myocardium surrounding the needle tip.
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Figure 2. Representative Look-Locker sequence MR images (3000/2.5; flip angle, 10°) obtained with a long-axis view of the heart. In the first image obtained after the inversion pulse (top left), the injection site cannot be differentiated from remote myocardium. The image acquired 228 msec after the inversion pulse (delay time after inversion pulse is in upper left corner of each image) shows the injection site (arrow) as dark because of faster zero crossing after intramyocardial injection of 0.10 mmol/mL gadodiamide solution at the injection site compared with remote myocardium. In consecutive images, the myocardium at the injection site gains bright signal intensity due to a shorter T1 value. The remote myocardium is dark at approximately 468 msec, corresponding to a T1 value of 885 msec ± 9 for myocardium. LV = left ventricle, RV = right ventricle.
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Figure 3. Plot shows changes in T1 values of myocardium at baseline and after injection of 0.10 mmol/mL and 0.05 mmol/mL gadodiamide (Gd-DTPA-BMA) solutions and remote myocardium during an observation period of 30 minutes (mean ± standard error of the mean). T1 values are significantly different for different concentrations at the same point in time of observation (P < .01) and increase significantly over the observation period (P < .05) because of diffusion and convection of the contrast medium. ms = milliseconds.
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Figure 4. Representative Look-Locker sequence MR images (3000/2.5; flip angle, 10°) obtained with a short-axis view of the left ventricle. There are two different injection sites: one immediately after injection of 0.1 mmol/mL gadodiamide (arrow) and one 15 minutes after injection of the same concentration (arrowhead). Zero crossing of the injection site immediately after injection is significantly faster compared with the injection site imaged 15 minutes after injection.
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Figure 5. Bar graph shows size of contrast-enhanced area after topical intramyocardial injection of 2 mL of 0.05 and 0.10 mmol/mL gadodiamide (Gd-DTPA-BMA) measured 3, 15, and 30 minutes after injection. Size of contrast-enhanced myocardium increased significantly (* = P < .05) during the observation period but was not significantly different between the two concentrations of gadodiamide (P > .1).
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Copyright © 2005 by the Radiological Society of North America.
