Scholarly article on topic 'Dependence of scar contrast in LGE images on the time interval after contrast injection'

Dependence of scar contrast in LGE images on the time interval after contrast injection Academic research paper on "Veterinary science"

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Academic research paper on topic "Dependence of scar contrast in LGE images on the time interval after contrast injection"

Vijayakumar et al. Journal of Cardiovascular Magnetic Resonance 2011, 13(Suppl 1):P42 http://jcmr-online.com/content/13/S1/P42

Magnetic Resonance

POSTER PRESENTATION Open Access

Dependence of scar contrast in LGE images on the time interval after contrast injection

Sathya Vijayakumar*, Eugene G Kholmovski, Nassir F Marrouche

From 2011 SCMR/Euro CMR Joint Scientific Sessions Nice, France. 3-6 February 2011

To study the dependence of post-ablation scar visibility in late gadolinium enhancement (LGE) images of left arial wall on time interval after contrast agent injection

Introduction

It was shown that LGE imaging can be used to evaluate post-ablation scar [1,2] and pre-ablation remodeling of left atrium [3]. Visibility of scar depends on a time interval between contrast agent injection and LGE scan. In this study, we try to determine, what time post contrast injection would give optimal contrast between post-ablation scar and blood (CNRSB) and scar and normal myocardium (CNRSM).

Methods

The study was performed retrospectively on 3-month post ablation LGE data acquired on a 3T Verio scanner (Siemens Healthcare, Erlangen, Germany) with a full dose (0.1mmol/kg) of contrast agent (Multihance, Bracco Diagnostic Inc., Princeton, NJ). The data were separated into 3 groups based on time post contrast:

1) 20-30 mins post contrast

2) 30-40 mins post contrast

3) 40-45 mins post contrast

Each group had 12 patients. Contrast to Noise Ratio (CNR) was computed as the ratio of the difference in signal intensity over a chosen region of interest in the scar and normal myocardium and the standard deviation

of the noise observed in the blood pool. CNR was computed between scar and normal myocardium CNRSM & between scar and blood CRNSB.

Results

Table 1 shows the results of the analysis. Figure 1 shows a comparative image of the CNR measurement made in 3 datasets, one from each group. Unpaired Student's t-test was performed on these datasets and the p values were found to be - p=0.24 (for CNRSB between <30min and 30-40min); p=0.69 (for CNRSB between 30-40min and >40min); p=0.97 (for CNRSM between <30min and 30-40min) and p=0.54 (for CNRSM between 30-40min and >40min). Thus, the difference in CNR between scar and normal myocardium and scar and blood observed in all three groups is not statistically significant.

Conclusion

From these preliminary results, it follows that LGE imaging performed between 25 to 45 minutes post contrast injection give comparable visibility of post ablation scar.

Table 1 CNR computed for each studied group

Time post contrast CNRSM (mean ± std) CRNSB (mean ± std)

25.2 ± 4 minutes 20.3 ± 9.1 8.7 ± 4.8

34.3 ± 2.5 minutes 20.2 ±8.8 11.3 ± 5.9 42. ± 2.8 minutes 17.3 ± 3.5 10 ± 1.9

University of Utah, Salt Lake City, UT, USA

O© 2011 Vijayakumar et al; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative CGntfcll Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Vijayakumar et al. Journal of Cardiovascular Magnetic Resonance 2011, 13(Suppl 1):P42 http://jcmr-online.com/content/13/S1/P42

Page 2 of 2

Figure 1 The measurement of CNR in representative images from the studied groups.

Published: 2 February 2011 References

1. Peters DC, et al: Radiology 2007, 243(3):690-5.

2. McGann CJ, et al: JACC 2008, 52(15):1263-71.

3. Oakes RS, et al: Circulation 2009, 119(13):1758-67.

doi:10.1186/1532-429X-13-S1-P42

Cite this article as: Vijayakumar et al.: Dependence of scar contrast in LGE images on the time interval after contrast injection. Journal of Cardiovascular Magnetic Resonance 2011 13(Suppl 1):P42.

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