Proton Magnetic Resonance Spectroscopic Imaging in Newly Diagnosed Glioblastoma
Predictive Value for the Site of Postradiotherapy Relapse in a Prospective Longitudinal Study
URL: http://sciencedirect.com/science?_ob=ArticleURL&_udi=B6T7X-4RSFS1Y-C…
Anne Laprie M.D., Ph.D*, †, , ,
Isabelle Catalaa M.D., Ph.D†, §,
Emmanuelle Cassol Ph.D.†,
Tracy R. McKnight Ph.D.¶,
Delphine Berchery M.D.,
Delphine Marre Ph.D.*,
Jean-Marc Bachaud M.D.*,
Isabelle Berry M.D., Ph.D†
Elizabeth Cohen-Jonathan Moyal M.D., Ph.D*, ‡
Department of Medical Information, Institut Claudius Regaud, Toulouse, France
†Laboratory of Biophysics and Medical Imaging, Universite Toulouse III Paul Sabatier, Toulouse, France
‡Department of Therapeutic Innovation and Molecular Oncology, Institut Claudius Regaud, INSERM, U563, Toulouse, France
*Department of Radiation Oncology, Institut Claudius Regaud, Toulouse, France
§Department of Neuroradiology, Hôpital Rangueil, CHU Toulouse, Toulouse, France
¶Center for Molecular and Functional Imaging, University of California–San Francisco, San Francisco, CA
Received 24 August 2007; revised 26 October 2007; accepted 30 October 2007. Available online 6 February 2008.
Purpose
To investigate the association between magnetic resonance spectroscopic imaging (MRSI)–defined, metabolically abnormal tumor regions and subsequent sites of relapse in data from patients treated with radiotherapy (RT) in a prospective clinical trial.
Methods and Materials
Twenty-three examinations were performed prospectively for 9 patients with newly diagnosed glioblastoma multiforme studied in a Phase I trial combining Tipifarnib and RT. The patients underwent magnetic resonance imaging (MRI) and MRSI before treatment and every 2 months until relapse. The MRSI data were categorized by the choline (Cho)/N-acetyl–aspartate (NAA) ratio (CNR) as a measure of spectroscopic abnormality. CNRs corresponding to T1 and T2 MRI for 1,207 voxels were evaluated before RT and at recurrence.
Results
Before treatment, areas of CNR2 (CNR ?2) represented 25% of the contrast-enhancing (T1CE) regions and 10% of abnormal T2 regions outside T1CE (HyperT2). The presence of CNR2 was often an early indicator of the site of relapse after therapy. In fact, 75% of the voxels within the T1CE+CNR2 before therapy continued to exhibit CNR2 at relapse, compared with 22% of the voxels within the T1CE with normal CNR (p < 0.05). The location of new contrast enhancement with CNR2 corresponded in 80% of the initial HyperT2+CNR2 vs. 20.7% of the HyperT2 voxels with normal CNR (p < 0.05).
ConclusionM
Metabolically active regions represented a small percentage of pretreatment MRI abnormalities and were predictive for the site of post-RT relapse. The incorporation of MRSI data in the definition of RT target volumes for selective boosting may be a promising avenue leading to increased local control of glioblastomas.
