TY - JOUR
T1 - Assessment of absolute blood volume in carcinoma by USPIO contrast-enhanced MRI
AU - Gambarota, Giulio
AU - Van Laarhoven, Hanneke W.M.
AU - Philippens, Marielle
AU - Lok, Jasper
AU - Van Der Kogel, Albert
AU - Punt, Cornelius J.A.
AU - Heerschap, Arend
N1 - Funding Information:
This study was supported by a grant from the Dutch Cancer Society, Grant KUN 2000-2307.
PY - 2006/4
Y1 - 2006/4
N2 - Objectives: The characterization of tumor vasculature is essential in studying tumor physiology. The aim of this study was to develop a new method - based on water proton MR density measurements, in combination with ultrasmall superparamagnetic iron oxide (USPIO) administration - to measure absolute blood volume (BV) in murine colon carcinoma. Materials and Methods: MRI experiments were performed at 7 T. CPMG imaging was performed on subcutaneous murine colon carcinoma in six mice before and after administration of an USPIO blood-pool contrast agent. Density maps were obtained from the signal amplitude at TE=0 of the CPMG decay fit. Post-USPIO density maps were subtracted from pre-USPIO density maps to quantitatively yield absolute tumor BV maps. In a separate group of mice (n=6), the relative vascular area (RVA) of tumors was determined by immunohistochemistry. Results: Ultrasmall superparamagnetic iron oxide administration resulted in a small decrease in the water proton MR density. The BV averaged over the six tumors was 4.6±1.6%. The value of the RVA measured by immunohistochemical staining was equal to 3.9±2.2%. Conclusions: After administration of an USPIO blood-pool agent (T2 relaxivity > 100 mM-1 s-1), the blood water protons become MRI invisible, and pixel-by-pixel BV map can be obtained by subtracting the calculated post-USPIO density map from the pre-USPIO density map. The value of absolute BV obtained with this novel MR approach is in good agreement with the value of the relative vascular measured by immunohistochemical staining.
AB - Objectives: The characterization of tumor vasculature is essential in studying tumor physiology. The aim of this study was to develop a new method - based on water proton MR density measurements, in combination with ultrasmall superparamagnetic iron oxide (USPIO) administration - to measure absolute blood volume (BV) in murine colon carcinoma. Materials and Methods: MRI experiments were performed at 7 T. CPMG imaging was performed on subcutaneous murine colon carcinoma in six mice before and after administration of an USPIO blood-pool contrast agent. Density maps were obtained from the signal amplitude at TE=0 of the CPMG decay fit. Post-USPIO density maps were subtracted from pre-USPIO density maps to quantitatively yield absolute tumor BV maps. In a separate group of mice (n=6), the relative vascular area (RVA) of tumors was determined by immunohistochemistry. Results: Ultrasmall superparamagnetic iron oxide administration resulted in a small decrease in the water proton MR density. The BV averaged over the six tumors was 4.6±1.6%. The value of the RVA measured by immunohistochemical staining was equal to 3.9±2.2%. Conclusions: After administration of an USPIO blood-pool agent (T2 relaxivity > 100 mM-1 s-1), the blood water protons become MRI invisible, and pixel-by-pixel BV map can be obtained by subtracting the calculated post-USPIO density map from the pre-USPIO density map. The value of absolute BV obtained with this novel MR approach is in good agreement with the value of the relative vascular measured by immunohistochemical staining.
KW - Absolute blood volume
KW - CPMG
KW - Murine colon carcinoma
KW - Ultra-small superparamagnetic iron oxide particles
UR - http://www.scopus.com/inward/record.url?scp=33645086698&partnerID=8YFLogxK
U2 - 10.1016/j.mri.2005.12.003
DO - 10.1016/j.mri.2005.12.003
M3 - Article
C2 - 16563957
AN - SCOPUS:33645086698
SN - 0730-725X
VL - 24
SP - 279
EP - 286
JO - Magnetic Resonance Imaging
JF - Magnetic Resonance Imaging
IS - 3
ER -