Magnetic resonance imaging of perfusion in humans using spin-tagging of arterial water.

Format:

Book

Thesis/Dissertation

Author/Creator:

Roberts, Dave, 1955-

Contributor:

Leigh, John S., Jr., advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Biophysics.

Medical physics.

Diagnostic imaging.

Radiology.

0574.

0760.

0786.

Penn dissertations--Biophysics.

Biophysics--Penn dissertations.

Local Subjects:

Penn dissertations--Biophysics.

Biophysics--Penn dissertations.

0574.

0760.

0786.

Physical Description:

210 pages

Contained In:

Dissertation Abstracts International 55-05B.

System Details:

Mode of access: World Wide Web.

text file

Summary:

Tissue perfusion is an important physiologic parameter which is altered in a large number of disease states, including ischemia, infarction, and cancer. This dissertation describes the implementation and evaluation of a noninvasive magnetic resonance perfusion imaging method in humans. This method employs steady-state magnetic labeling, or "spin-tagging", of arterial water which then behaves as an endogenous freely-diffusible tracer. The Bloch equation, modified to include terms for perfusion and exchange, yields a solution for tissue-specific perfusion. The principle of transport-induced adiabatic fast passage is used to effect steady-state inversion of arterial water. Perfusion maps are calculated from images acquired with and without arterial spin-tagging and from a map of the apparent longitudinal relaxation time, measured by an inversion-recovery experiment. An approximate resolution in brain of (2 x 4 x 5) mm is obtained in an acquisition time of 15 minutes. Average perfusion rates of 74 $\pm$ 14, 45 $\pm$ 16, and 58 $\pm$ 11 $\rm ml{\cdot}100g\sp{-1}{\cdot}min\sp{-1}$ are obtained for gray matter, white matter, and whole brain, respectively. Data from human kidney yield average blood flow rates of 343 $\pm$ 94 and 56 $\pm$ 29 $\rm ml{\cdot}100g\sp{-1}{\cdot}min\sp{-1}$ for cortex and medulla, respectively. Alterations in cerebral perfusion are observed during changes in the respiratory status as well as during performance of a motor task. The degree of arterial inversion is measured directly using a flow-visualization technique. Errors due to off-resonance effects of the inversion pulse, chemical shift, magnetic susceptibility, blood volume, and transit-time are examined. The results demonstrate that quantitative perfusion imaging may be performed in humans using magnetic spin-tagging of arterial water. Because spin-tagging is non-invasive, repeated study of the same individual or of children is possible. The experimental design is simple, requiring only minor modifications to a standard imaging system. This technique may find application in the diagnosis and management of a number of important diseases as well as in the field of cognitive neuroscience.

Notes:

Thesis (Ph.D. in Biophysics) -- Graduate School of Arts and Sciences, University of Pennsylvania, 1994.

Source: Dissertation Abstracts International, Volume: 55-05, Section: B, page: 1770.

Adviser: John S. Leigh, Jr.

Local Notes:

School code: 0175.

Access Restriction:

Restricted for use by site license.