Biosketch / Results /
Glyn JohnsonAdjunct Associate Professor, Department of Radiology
Research SummaryMRI Assessment of Tumor Hemodynamics
Angiogenesis, the creation of new blood vessels, is characteristic of solid tumors and crucial for their development. Accurate quantification of angiogenesis allows differentiation of tumors from non-malignant lesions, differentiation of tumors of different types and monitoring of treatment.
Improved methods of monitoring angiogenesis by dynamic, contrast enhanced magnetic resonance imaging are being developed. A series of images is acquired at one second intervals during the injection of a bolus of contrast agent. Tissue contrast agent concentration can then be calculated from changes in image intensity during bolus passage through the tumor. Vascular volume and vascular permeability can then be calculated from the concentration-time curves.
It has been found that MRI measurements of vascular volume and permeability can be used to differentiate a wide range of non-malignant lesions from tumors despite similar appearance on conventional MRI, to grade tumors and to monitor the efficacy of antiangiogenic treatment.
Functional Lung Imaging
Conventional MRI of water protons provides very little information on the lung which consists mostly of air spaces. However, novel imaging methods have recently been developed that form images of inhaled hyperpolarized helium. Novel methods of using helium MRI to measure lung function as well as demonstrate lung anatomy are being developed.