Intracranial tumor response to respiratory challenges at 3.0 T: Impact of different methods to quantify changes in the MR relaxation rate R2*
✍ Scribed by Andreas Müller; Stefanie Remmele; Ingobert Wenningmann; Hans Clusmann; Frank Träber; Sebastian Flacke; Roy König; Jürgen Gieseke; Winfried A. Willinek; Hans H. Schild; Petra Mürtz
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 178 KB
- Volume
- 32
- Category
- Article
- ISSN
- 1053-1807
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✦ Synopsis
Abstract
Purpose:
To compare two ΔR2* quantification methods for analyzing the response of intracranial tumors to different breathing gases. The determination of changes in the magnetic resonance imaging (MRI) relaxation rate R2* (ΔR2*), induced by hyperoxic and hypercapnic respiratory challenges, enables the noninvasive assessment of blood oxygenation changes and vasoreactivity.
Materials and Methods:
Sixteen patients with various intracranial tumors were examined at 3.0 T. The response to respiratory challenges was registered using a dynamic multigradient‐echo sequence with high temporal and spatial resolution. At each dynamic step, ΔR2* was derived in two different ways: 1) by subtraction of R2* values obtained from monoexponential decay functions, 2) by computing ΔR2* echo‐wise from signal intensity ratios. The sensitivity for detection of responding voxels and the behavior of the “global” response were investigated.
Results:
Significantly more responding voxels (about 4%) were found for method (1). The “global” response was independent from the chosen quantification method but showed slightly larger changes (about 6%) when ΔR2* was derived from method (1).
Conclusion:
Similar results were observed for the two methods, with a slightly higher detection sensitivity of responding voxels when ΔR2* was obtained from monoexponential approximation. J. Magn. Reson. Imaging 2010;32:17–23. © 2010 Wiley‐Liss, Inc.