Vahid Yaghmai MD, Abstract Co-Author: Nothing to Disclose

Keyur Parekh MD, Abstract Co-Author: Grant, Siemens AG

Adeel Rahim Seyal MD, Presenter: Grant, Siemens AG

Thomas Patrick O'Donnell, Abstract Co-Author: Researcher, Siemens AG

Bevacizumab, an antiangiogenic agent, can lead to morphological changes in colorectal liver metastasis. Tumor margin intensity slope (TMIS) was used to objectively quantify morphological changes in liver metastasis after treatment.

The HIPAA compliant retrospective study was approved by IRB. Seventy-two colorectal liver metastases in 29 patients treated with bevacizumab with at least one pre- and one post-treatment MDCT scan were evaluated. Metastasis response was classified as optimal, incomplete or no response according to changes in tumor density, enhancement and margins (morphologic criteria). Tumor margin intensity slope, the first derivative of the plot of median intensities of concentric layers of voxels from outside the tumor towards its core, was calculated to compare different response categories. A greater negative value of TMIS corresponds to sharper tumor margins. Treatment response groups were compared using one-way analysis of variance (ANOVA). Student-Newman-Keuls test was applied for multiple comparisons.

Based on the morphological changes, 23/72 metastasis showed optimal response with remainder showing either incomplete (29/72) or no response (20/72). Mean TMIS values were -11.65 ± 3.5 HU/layer, -8.74 ± 5.2 HU/layer, and -7.58 ± 4.8 HU/layer (P=0.013) for lesions with optimal, incomplete and no response, respectively. On multiple comparisons, TMIS was significantly different for optimal response when compared with incomplete and no response. TMIS values between the latter two groups were comparable (P>0.05).

Tumor margin intensity slope provides objective quantification of morphological changes in colorectal liver metastasis and identifies lesions with optimal response to bevacizumab treatment.

Tumor margin intensity slope is a promising imaging biomarker of response in colorectal liver metastases treated with antiangiogenics.

Yaghmai, V, Parekh, K, Seyal, A, O'Donnell, T, Tumor Margin Intensity Slope to Quantify Morphological Changes in Colorectal Liver Metastasis after Anti-angiogenic Therapy.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14012277.html