Nobuyuki Kosaka MD, Presenter: Nothing to Disclose

Hidemasa Uematsu MD, PhD, Abstract Co-Author: Nothing to Disclose

Hirohiko Kimura MD, PhD, Abstract Co-Author: Nothing to Disclose

Yoshiyuki Ishimori PhD, Abstract Co-Author: Nothing to Disclose

Tetuji Kurokawa MD, Abstract Co-Author: Nothing to Disclose

Harumi Itoh MD, Abstract Co-Author: Nothing to Disclose

Recent advances in magnetic resonance (MR) techniques allow the assessment of tissue perfusion such as blood volume in various tumors of the central nervous system. The relative tumor blood volume (rBV) provided by perfusion-weighted MRI (PWI) has been used to evaluate the aggressiveness of tumors and effectiveness of therapy. PWI can be applied to pelvic organs such as the uterus. However, to the best of our knowledge, validation of PWI-calculated rBV by histopathologic analysis has not been performed in pelvic organs. In this study, our aim was to evaluate the feasibility of PWI in the pelvic organs by correlating it with histopathologic analysis of uterine leiomyoma.

Twelve patients with 15 uterine leiomyomas were included in this study. PWI was performed with a 1.5T MR scanner using a double-echo gradient-echo sequence to obtain a T1-bias-free estimate of the time-concentration curve. The rBV was calculated in relation to the external iliac artery. We also produced parametric maps to visually evaluate the rBV of tumors. Histologic sections of each tumor corresponding to the PWI slice were immunostained using an endothelial marker (CD34). The vascular area (VA) was defined as the total area of inside of the immunostained blood vessels divided by the whole area of the field of view. The VAs of 3 histologic sections were averaged.

In the semi-quantitative analysis, the rBV calculated by PWI ranged from 0.06 to 0.55 (0.18 ± 0.13: means ± SD), and the VA ranged from 1.7 to 8.5 (3.22 ± 1.63). Because one tumor had significantly higher rBV and VA than the others (rBV=0.55, VA=8.5), we excluded it from the statistical analysis. The correlation between rBV and VA was statistically significant (r2=0.67, p<0.001). In the visual assessment, higher rBVs corresponded to higher VAs. Thus, the degree of rBV on the parametric map was concordant with the degree of VA.

Our results suggest that the rBV calculated by PWI reflects tumor vascularity as determined by histopathology. PWI may be reliable for further clinical applications in the pelvic organs.

Recent advances in magnetic resonance (MR) techniques allow the assessment of tissue perfusion such as blood volume in various tumors of the central nervous system. The relative tumor blood volume (rBV) provided by perfusion-weighted MRI (PWI) has been used to evaluate the aggressiveness of tumors and effectiveness of therapy. PWI can be applied to pelvic organs such as the uterus. However, to the best of our knowledge, validation of PWI-calculated rBV by histopathologic analysis has not been performed in pelvic organs. In this study, our aim was to evaluate the feasibility of PWI in the pelvic organs by correlating it with histopathologic analysis of uterine leiomyoma.

Twelve patients with 15 uterine leiomyomas were included in this study. PWI was performed with a 1.5T MR scanner using a double-echo gradient-echo sequence to obtain a T1-bias-free estimate of the time-concentration curve. The rBV was calculated in relation to the external iliac artery. We also produced parametric maps to visually evaluate the rBV of tumors. Histologic sections of each tumor corresponding to the PWI slice were immunostained using an endothelial marker (CD34). The vascular area (VA) was defined as the total area of inside of the immunostained blood vessels divided by the whole area of the field of view. The VAs of 3 histologic sections were averaged.

In the semi-quantitative analysis, the rBV calculated by PWI ranged from 0.06 to 0.55 (0.18 ± 0.13: means ± SD), and the VA ranged from 1.7 to 8.5 (3.22 ± 1.63). Because one tumor had significantly higher rBV and VA than the others (rBV=0.55, VA=8.5), we excluded it from the statistical analysis. The correlation between rBV and VA was statistically significant (r2=0.67, p<0.001). In the visual assessment, higher rBVs corresponded to higher VAs. Thus, the degree of rBV on the parametric map was concordant with the degree of VA.

Our results suggest that the rBV calculated by PWI reflects tumor vascularity as determined by histopathology. PWI may be reliable for further clinical applications in the pelvic organs.

Kosaka, N, Uematsu, H, Kimura, H, Ishimori, Y, Kurokawa, T, Itoh, H, Semiquantitative Measurement of the Vascularity of Uterine Leiomyomas by Double-Echo Dynamic Perfusion-weighted MRI: Correlation with Histopathology.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4405777.html