E³ 1422 - Advanced imaging techniques in brain tumours
E³ 1422 - Advanced imaging techniques in brain tumoursSaturday, March 4, 10:30 - 12:00 Room: M 5 Session Type: E³ - ECR Academies: Neuroradiology: from Morphology to Function Topics: Nuclear Medicine, Physics in Medical Imaging, Neuro Moderator: P. C. Maly Sundgren (Lund/SE) Add session to my schedule In your schedule (remove)
As session chairman, I will give a brief introduction to the topics related to advanced techniques in brain tumour imaging that will be discussed in this session and give some highlight as well as some future ideas regarding advanced brain tumour imaging with respect to new magnetic resonance imaging sequences.
1. To provide practical tips and tricks for performing CT and MR perfusion in patients with brain tumours.
2. To illustrate how certain perfusion derived parameters (rCBV) can be correlated with tumour histology (e.g. angiogenesis, capillary leakage, malignancy grade).
3. To show that intense contrast enhancement is not identical to perfusion.
"no abstract submitted"
1. To show that amino acid PET is gaining increasing importance in assessment of tumour activity and malignancy.
2. To demonstrate how amino acid PET can be useful in glioma delineation for treatment planning (e.g., resection, biopsy, radiation), detection of post-therapeutic effects, assessment of treatment response, and prognostication.
3. To provide information on new PET tracers (targeting tumour hypoxia, enzymes in neoplastic metabolic pathways, etc.) and the combination of tracers with therapeutic agents.
In the last years, PET using radiolabelled amino acids has gained increasing interest in the diagnostics of brain tumour patients and has been established in many neurooncological centres as a complementary diagnostic tool to conventional MRI. Amino acid PET offers important additional information in the diagnosis of unclear space-occupying brain lesions and an improved delineation of glioma extent, which is helpful for biopsy guidance, planning of resection and radiation therapy. Furthermore, amino acid PET imaging may provide prognostic information in untreated, newly diagnosed glioma patients, helps to differentiate tumour progression or recurrence from treatment-related changes in low- and high-grade gliomas as well as in brain metastasis (e.g. pseudoprogression, radiation necrosis) and allows to evaluate the metabolic response following brain tumour therapy, particularly chemoradiation, alkylating chemotherapy and antiangiogenic therapy, earlier than with conventional MRI.
C. Assessment of brain tumour perfusion and abnormal vascular structure using arterial spin-labelling
1. To offer a short update on the physical principles and technique of arterial spin-labelling in assessing brain tumour perfusion.
2. To review the advantages and disadvantages of ASL as compared to contrast-enhanced perfusion imaging.
3. To provide clinical examples where ASL has contributed significantly to management and clinical decision making in brain tumour patients.
Haemodynamic alterations are present in many brain tumours, and in general, CBF and cerebral blood volume (CBV) increase with grade. Much of our MR imaging-based knowledge about these changes has been gained from Gd-based techniques, in particular dynamic susceptibility contrast (DSC) and dynamic contrast-enhanced (DCE) imaging. Thus, so far, most literature has focused on relative CBV changes, because it is easier to assess using such techniques than CBF, and most of the data available are of relatively poor spatial resolution and prone to artefacts, due to the rapid passage of the intravascularly confined tracer necessitates. ASL cannot measure relative CBV, but provides a straightforward assessment of CBF. In particular, since water has high permeability in the normal and neoplastic tissue, there is no need with ASL to use complicated leakage-correction algorithms to obtain quantitative results. Initial reports demonstrated that ASL and DSC show largely concordant results in glioblastoma multiformae (GBM) (for reference, see 1). Higher CBF in GBM correlates with genetic markers and is associated with shorter progression-free survival time. Lower grade tumours typically demonstrate lower CBF. In fact, some have suggested that CBF quantification provides a better estimate of event-free survival for a wide range of gliomas than does a histologic grading scale. Finally, CBF has also been used to assess metastatic disease and treatment response, in particular in the assessment of radiation necrosis vs. recurrence. Ref: 1) Haller et al., Radiology, 281(2):337-356 (2016).