Diffusion tensor imaging for target volume definition in glioblastoma multiforme

作者：Berberat Jatta^*; McNamara Jane; Remonda Luca; Bodis Stephan; Rogers Susanne

来源：Strahlentherapie und Onkologie, 2014, 190(10): 939-943.

DOI：10.1007/s00066-014-0676-3

• Magnetic resonance imaging
• White matter
• Intensity-modulated radiation therapy
• Glioma
• Recurrence

Introduction. Diffusion tensor imaging (DTI) is an MR-based technique that may better detect the peritumoural region than MRI. Our aim was to explore the feasibility of using DTI for target volume delineation in glioblastoma patients.
Materials and methods. MR tensor tracts and maps of the isotropic (p) and anisotropic (q) components of water diffusion were coregistered with CT in 13 glioblastoma patients. An in-house image processing program was used to analyse water diffusion in each voxel of interest in the region of the tumour. Tumour infiltration was mapped according to validated criteria and contralateral normal brain was used as an internal control. A clinical target volume (CTV) was generated based on the T-1-weighted image obtained using contrast agent (T-1Gd), tractography and the infiltration map. This was compared to a conventional T-2-weighted CTV (T-2-w CTV).
Results. Definition of a diffusion-based CTV that included the adjacent white matter tracts proved highly feasible. A statistically significant difference was detected between the DTI-CTV and T-2-w CTV volumes (p < 0.005, t = 3.480). As the DTI-CTVs were smaller than the T-2-w CTVs (tumour plus peritumoural oedema), the pq maps were not simply detecting oedema. Compared to the clinical planning target volume (PTV), the DTI-PTV showed a trend towards volume reduction. These diffusion-based volumes were smaller than conventional volumes, yet still included sites of tumour recurrence.
Conclusion. Extending the CTV along the abnormal tensor tracts in order to preserve coverage of the likely routes of dissemination, whilst sparing uninvolved brain, is a rational approach to individualising radiotherapy planning for glioblastoma patients.

• 出版日期2014-10