Leeds Institute of Cardiovascular and Metabolic Medicine
University of Leeds/UK
Matthias van Osch
Department of Radiology
Leiden University Medical Center
M. Günther, M. Jerosch-Herold, L. Ostergaard, S. Sourbron, M. van Osch, F. von Samson-Himmelstjerna
Goals of the course:
The course on Measurement of perfusion and capillary exchange provides an overview of modern technologies for perfusion imaging with a focus on MRI modalities. The variety
of methods that have been developed in the past is presented and analysed critically. The course is aimed at providing the participants with criteria for deliberate selection of methods in their studies. The in-depth analysis is based on the underlying physics of perfusion encoding, the theory of contrast agent effects on the MR signal and the mathematics of data processing. The course will provide practical tips and tricks for your next perfusion studies.
This course is intended for MR physicists, other scientists and PhD students who already have experience in basic MR methods and knowledge of MR acquisition principles, and who want to get a deeper insight into perfusion imaging and underlying physiological processes and physics.
This course is designed to provide deeper insight into the biophysics of perfusion, the consequential requirements to the data acquisition and MR methodology for qualitative and quantitative data evaluation. After an overview of and introduction to the basics of physiology and the clinical role of perfusion imaging, the general theory behind perfusion quantification is explained. An overview of existing perfusion imaging techniques is given.
An introduction to arterial spin labeling (ASL) techniques and associated data processing strategies is presented, emphasizing the theory behind quantification approaches. Differences in quantification of continuous and pulsed ASL are discussed, as well as the influence of partial volume effects and prolonged transit time.
Perfusion MRI using contrast agents will concentrate on dynamic susceptibility contrast (DSC) MRI as well as dynamic contrast enhanced (DCE) MRI. The differences in tracer kinetics are explained and demonstrated. The theory of relaxation enhancement induced by the contrast agent is discussed.
As an integral part, the course will also include a substantial amount of time that will be spent on exercises, which are intended to enhance the understanding of basic and advanced topics and will be performed, e.g. by means of simulations under guidance of the lecturers.
The course is designed to provide a compact understanding and a stable foundation for scientists who intend to enhance their knowledge with respect to perfusion-weighted MR imaging or who wish to get involved with method development of perfusion measurements. This course is not focused on a particular organ, although for ASL the brain is still the organ in which it is applied most often.
Learning objectives: Physiology
•Hemodynamics and perfusion regulation
•Characteristics of tissue perfusion
•Clinical importance of perfusion-related parameters
•Theory of perfusion and tracer-kinetics
•Assessment of perfusion using diffusible and non-diffusible tracers
•Imaging modality (SPECT, PET, CT, Ultrasound, MRI)
•Leakage of contrast agent, (extended) Tofts model, other models
Arterial spin labeling (ASL)
•Basic principles of ASL
•(pseudo-)Continuous versus pulsed ASL
•Implementation and labeling schemes
•Quantification, QUIPSS, transit time, multi-TI, multi-PLD, Hadamard-encoded
•Readout modules, 2D, 3D, multi-slice, background suppression
Dynamic susceptibility contrast perfusion imaging (DSC-MRI) and dynamic contrast enhanced (DCE) imaging
•Types of MR contrast agents and their kinetics in body fluids
•The effect of contrast agent on tissue relaxation: T1, T2 and T2*-relaxivity, the role of water exchange.
•Basic types of imaging sequences in DSC (GE and SE) and DCE (2D and 3D), multi-echo sequences
•DSC and DCE signal theory – relating dynamic signals to concentrations
•Specific methods for specific body areas, incl. clinical applications
Software for ASL, DSC and DCE
•Learn about the capabilities of ASL, DSC and DCE using computer simulations
•Explore dependency on imaging and physiologic parameters
•Learn to process patient data with open source tools