Perfusion MRI And Other Perfusion Imaging Techniques For Clinical Trials

By Vera Kovacevic, PhD, and Edward Ashton, PhD

Magnetic resonance imaging (MRI) has had a part in clinical trials for more than three decades now. For most of this time, MRI mainly was used for qualitative interpretation and simple structural measurements. However, the role of MRI in new drug clinical trials can involve diagnosis of lesions and determination of their severity, early identification of therapeutic responders to drug treatment and treatment monitoring and follow-up. MRI may also be used to evaluate drug dosing regimens, to gain insight about the mechanism of drug action, and to collect imaging biomarker data which could provide an earlier indication of response to therapy than clinical outcomes.

Clinical trials are increasingly using advanced MRI techniques to help evaluate the efficacy of investigational therapeutics. In the past decade or so, there has been considerable development in MRI methods for the evaluation of functional tissue properties, such as perfusion. Such advanced MRI techniques can be valuable in the drug development process because they can enable a better measurement of treatment-related changes compared to other imaging modalities.

Perfusion is the passage of fluid through the lymphatic system or the circulatory system to an organ or tissue, and it typically refers to the delivery of blood to a capillary bed in tissue. Perfusion imaging done by MRI has been used to assess the intrinsic microvascular properties of tumors before, during and after treatment with anti-angiogenic and vascular-targeting agents.

Features of blood perfusion in the brain detected by MRI now have clinical applications in central nervous system (CNS) cancers, neurodegenerative disease, cerebrovascular disease and demyelinating disease.

Currently, MRI-based perfusion imaging is also being applied to measure changes in inflammation in patients with rheumatoid arthritis and osteoarthritis.

Various perfusion-related parameters can be measured using dynamic contrast-enhanced MRI (DCE-MRI). Other techniques are also applied for perfusion imaging, such as dynamic-susceptibility contrast MRI (DSC-MRI), and dynamic contrast-enhanced ultrasound (DCE-US) or computed tomography (DCE-CT).

“DCE-MRI and other perfusion techniques are very sensitive and can be quite difficult to run within a trial. We [Philips Pharma Solutions, formerly BioTel Research] have successfully ran multi-site DCE-MRI trials,” said Edward Ashton, PhD, VP, Oncology Imaging, Philips Pharma Solutions.

Read on to learn about perfusion imaging techniques and their use for clinical trials, with particular focus on perfusion imaging using DCE-MRI.