MRI assessment of percutaneous ablation of liver tumors: Value of subtraction images
Article first published online: 28 SEP 2012
Copyright © 2012 Wiley Periodicals, Inc.
Journal of Magnetic Resonance Imaging
Volume 37, Issue 2, pages 407–413, February 2013
How to Cite
Tatli, S., Acar, M., Tuncali, K., Sadow, C. A., Morrison, P. R. and Silverman, S. G. (2013), MRI assessment of percutaneous ablation of liver tumors: Value of subtraction images. J. Magn. Reson. Imaging, 37: 407–413. doi: 10.1002/jmri.23827
- Issue published online: 24 JAN 2013
- Article first published online: 28 SEP 2012
- Manuscript Received:
- Manuscript Accepted:
- image-guided therapy;
- tumor ablation;
- contrast enhancement;
To evaluate the value of subtraction images when using MRI to assess liver tumors treated with percutaneous ablation.
Materials and Methods:
Following percutaneous ablation of 35 liver tumors, two abdominal radiologists, blinded to outcomes, independently reviewed follow-up MRI examinations for tumoral enhancement suggestive of residual/recurrent tumor and rated their confidence level. After one year, the readers reviewed the same examinations with added subtraction images. Accuracy of the detection of residual/recurrent tumor and contrast-to-noise ratios (CNR; for tumoral enhancement-to-liver, tumoral enhancement-to-ablation zone, and ablation zone-to-liver) were calculated with and without subtraction images and compared using Wilcoxon signed rank test. Interobserver variability was computed using Kappa (κ) statistics.
Residual/recurrent tumor was present in 8 (23.5%) of 34 tumors. Accuracy of detecting residual/recurrent tumor with subtraction images and interobserver agreement (κ = 0.72, good) were better than accuracy of detecting residual/recurrent tumor and interobserver agreement (κ = 0.57, moderate) of enhanced MR images without subtraction. Mean CNR of subtraction images was significantly higher than that of enhanced MR images for tumoral enhancement-to-liver (0.2 ± 5 versus 11.6 ± 14.4, P = 0.03), tumoral enhancement-to-ablation zone (10.1 ± 12.5 versus 34.4 ± 29.4, P = 0.02), and ablation zone-to-liver (11.8 ± 13.3 versus 102.5 ± 238.4, P = 0.03).
When using MRI, subtraction images help both detect and exclude residual/recurrent tumor following percutaneous liver ablations. J. Magn. Reson. Imaging 2013;37:407–413. © 2012 Wiley Periodicals, Inc.