Original ArticleAssessment of Irradiated Brain Metastases by Means of Arterial Spin-Labeling and Dynamic Susceptibility-Weighted Contrast-Enhanced Perfusion MRI Initial ResultsWeber, Marc-André MD*; Thilmann, Christoph MD†; Lichy, Matthias P. MD*; Günther, Matthias PhD‡; Delorme, Stefan MD*; Zuna, Ivan PhD†; Bongers, André PhD‡; Schad, Lothar R. PhD‡; Debus, Jürgen MD, PhD†; Kauczor, Hans-Ulrich MD*; Essig, Marco MD*; Schlemmer, Heinz-Peter MD*Author Information From the *Division of Radiology, †Division of Radiation Oncology, and the ‡Division of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany. Matthias Günther's present address is Advanced MRI Technologies, 652 Petaluma Avenue, Suite I, Sebastopol, CA 95472, USA. Heinz-Peter Schlemmer's present address is Department of Radiology, University of Tuebingen, Hoppe-Seyler-Str. 3, D-72076 Tuebingen, Germany. Received November 3, 2003 and accepted for publication, after revision, January 15, 2004. Reprints: Marc-André Weber, MD, Division of Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany; E-mail: [email protected] Investigative Radiology: May 2004 - Volume 39 - Issue 5 - p 277-287 doi: 10.1097/01.rli.0000119195.50515.04 Buy Metrics Abstract Rationale and Objectives: To assess if preradiation and early follow-up measurements of relative regional cerebral blood flow (rrCBF) can predict treatment outcome in patients with cerebral metastases and to evaluate rrCBF changes in tumor and normal tissue after stereotactic radiosurgery using arterial spin-labeling (ASL) and first-pass dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion MRI. Methods: In 25 patients with a total of 28 brain metastases, DSC MRI and ASL perfusion MRI using the Q2TIPS sequence were performed with a 1.5-T unit. Measurements were performed prior to and at 6 weeks, 12 weeks, and 24 weeks after stereotactic radiosurgery. Follow-up examinations were completely available in 25 patients for Q2TIPS and 17 patients with 18 metastases for DSC MRI. The rrCBF of the metastases and the normal brain tissue was determined by a region-of-interest analysis. rrCBF values were correlated with the treatment outcome that was classified according to tumor volume changes at 6 months. Results: The alteration of the rrCBF at the 6-week follow-up was highly predictive for treatment outcome. A decrease of the rrCBF value predicted tumor response correctly in all metastases for Q2TIPS and in 13 of 16 metastases for DSC MRI. The pretherapeutic rrCBF was not able to predict treatment outcome. The rrCBF values in normal brain tissue affected by radiation doses less than 0.5 Gy remained unchanged after therapy. Conclusion: These preliminary results suggest that ASL and DSC MRI techniques determining rrCBF changes in brain metastases after stereotactic radiosurgery allow the prediction of treatment outcome. © 2004 Lippincott Williams & Wilkins, Inc.