Kejia Cai PhD, Presenter: Nothing to Disclose

Karen Xie DO, Abstract Co-Author: Nothing to Disclose

Jillian A. Karow MD, Abstract Co-Author: Nothing to Disclose

Lauren Green MD, Abstract Co-Author: Nothing to Disclose

Alison Palumbo MD, Abstract Co-Author: Nothing to Disclose

Xiaohong Joe Zhou PhD, Abstract Co-Author: Nothing to Disclose

Grace Knuttinen, Abstract Co-Author: Nothing to Disclose

Uterine artery embolization (UAE) has emerged to be an effective treatment option for women with symptomatic uterine leiomyomas. Factors to predict treatment outcome before UAE is critical for patient selection, procedure planning and postprocedural follow up. Previous studies using MRI have shown variable correlations between MRI predictors and the responses to UAE. Our study is to investigate whether tumor MR contrast normalized to surrounding normal myometrium, the relative contrast, may predict the fibroid response to UAE given that both MR contrast enhancement and UAE are related to tumor vascularization.

The study was performed under an approved IRB protocol. Eight patients (cumulative tumor number n = 42) completed pre and 3-6 moths post treatment contrast-enhanced MRI of pelvis at 3T using a fat-suppressed 3D gradient-echo T1-weighted sequence pre and post administration of Gadolinium (0.01 mmol/kg). 100 -200 axial slices were acquired with a slice thickness of 5mm,TR/TE=5.2/2.5 ms, and in-plane resolution less than 1 x 1 mm2. Tumor relative contrast and contrast to noise ratio (CNR) were quantified. Two-tailed unpaired Student’s t tests were performed and a significance level was set at p<0.05.

After UAE treatment, 33/42 leiomyomas were found to be completely necrotic and considered to be fully responsive (group A). The remaining 9/42 leiomyomas showed partial or no necrosis, considered to be partial responsive or nonresponsive (group B). Group A exhibited significantly higher relative contrast than group B (1.6±0.4 vs. 1.0±0.4, *p<0.05). While, the conventional CNRs of these two groups were not significantly different (74.2±24.8 vs. 64.6±38.6, p=0.34). Using an optimum threshold of 1.3, pre-UAE tumor relative contrast correctly predicted 7/9 not-fully responsive tumors and 30/33 fully responsive tumors. On the other hand, tumor CNR correctly predicted 7/9 not-fully responsive tumors while only 22/33 fully responsive tumors at its optimum threshold of 70.

With a limited sample size, we demonstrated that pre-UAE highly enhanced leiomyomas were found more likely to have poor response to UAE presumably due to the presence of complex tumor vasculature, including existing collateral supplies in the poorly responsive tumors.

Upon further validation, pre-UAE normalized relative contrast may help to predict UAE treatment outcome of leiomyomas.

Cai, K, Xie, K, Karow, J, Green, L, Palumbo, A, Zhou, X, Knuttinen, G, Normalized Relative Contrast May Improve the Power of Contrast-Enhanced MRI to Predict the Prognosis of Uterine Leiomyoma Treated with Uterine Artery Embolization.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14003665.html