Sith Phongkitkarun MD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: Vascular permeability is a fundamental property of vessels in tumor angiogenesis. Its evaluation has the potential to monitor the effects of antiangiogenic therapy. Recently developed functional CT (fCT) can derive the permeability surface area product (PS), but PS is expected to vary with molecular weights of the contrast medium and the duration of data acquisition. In this study, we measure PS in a murine mammary tumor model, using contrast agents of two different molecular weights, and two different durations of data acquisition. Methods and Materials: FCT was performed on tumors in mammary fat pads of nine Fisher rats two weeks after implantation of a murine mammary cancer cell line (FN13762). We used low molecular weight contrast media (MWCM) at 1.0ml/kg (Ioversol, 320mg iodine/ml, Mallinckrodt Inc, MO, 0.8 kDa) and high MWCM at 1.5ml/kg (P743, 225 mg iodine/ml, Guerbet, France, 13 kDa), injected sequentially after a 2-hour delay. CT data was acquired in a cine mode (1s scan time) for 50 seconds and subsequently delayed phases every 30 seconds for 10 minutes. We used the initial 'cine only' and combined 'cine and delayed' data and CT perfusion 3 software (GE Medical Systems, WI) to measure PS in the tumors and the normal liver. Differences in PS between the low and high MWCM and between the modes of data acquisition were compared using the paired t-test. Results: There was a significant difference in PS in the tumors between the low and high MWCM in both the 'cine only' data, (mean±SD) 13.7±3.2 vs. 3.7±1.6 ml/min/100g (p<0.01); and the 'cine and delayed' data, 5.0±1.0 vs. 1.1±0.7 (p<0.01), respectively. PS was also significantly different in PS between the 'cine only' and 'cine and delayed' data in the same MWCM (p<0.01). Significant differences were also demonstrated in the normal liver between low and high MWCM, with the 'cine only' data, 12.1±3.9 vs. 5.1±2.6 (p=0.01); but not in the 'cine and delay' data, 2.6±2.0 vs. 0.8±0.8 (p=0.2), respectively. Conclusion: Measurement of vascular permeability is affected by the molecular weight of contrast medium used and the duration of fCT data acquisition. We speculate that high MWCM may provide a better estimate of permeability in tissues with high leakage. (S.P. will use the name of the contrast medium, P743, that was provided by the Guerbet Company. T.L. has received a grant from GE Medical Systems.)       Questions about this event email: phongkitkarun_sith@hotmail.com

Phongkitkarun MD, S, Vascular Permeability of a Murine Mammary Tumor Model Assessed by Functional CT Using Low and High Molecular Weight Contrast Media.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3102155.html