Dynamic susceptibility contrast perfusion imaging of radiation effects in normal-appearing brain tissue: Changes in the first-pass and recirculation phases

✍ Scribed by Michael C. Lee; Soonmee Cha; Susan M. Chang; Sarah J. Nelson

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 585 KB
• Volume: 21
• Category: Article
• ISSN: 1053-1807
• DOI: 10.1002/jmri.20298

✦ Synopsis

Abstract

Purpose

To identify radiation‐induced changes in the cerebral vasculature of healthy tissue in the first four months following radiotherapy through the analysis of dynamic‐susceptibility contrast perfusion imaging.

Materials and Methods

Dynamic gradient‐echo imaging was performed on 22 patients during injection of a bolus of Gd‐DTPA contrast. The relative cerebral blood volume (rCBV), maximum ΔR2* of the first passage of the bolus, and a recirculation parameter were derived from gamma‐variate fits of the dynamic data. The white matter (WM) rCBV and peak heights were estimated through correlation with segmented T1‐weighted images. A percent recovery to baseline was also computed to further describe the recirculation phase.

Results

A significant elevation of the recirculation phase was observed at doses > 15 Gy at two months following radiotherapy. This was reflected in an increased recirculation parameter in the fitted curves in the 15–30, 30–45, and >45 Gy dose groups to 2.8%, 3.8%, and 2.4% above the <15 Gy voxels, as well as in a decline in percent recovery to baseline. A trend toward lower rCBV and peak heights was observed at that same time point.

Conclusion

The observed results suggest a dose‐dependent decline in vessel density and increase in vascular permeability and/or tortuosity in irradiated normal‐appearing brain tissue at two months following radiotherapy. J. Magn. Reson. Imaging 2005;21:683–693. © 2005 Wiley‐Liss, Inc.