ABSTRACT
I. Introduction 242
II. Blood Flow and MR Signal 242
A. Flow-Related Phenomena 242
B. Velocity Measurement in Great Vessels Using
Phase Shift 243
C. Micromovement Evaluation by MRI 245
D. Development of Lung Parenchymal
Perfusion Imaging 247
III. Perfusion Imaging with HASTE 247
A. Principle of HASTE 247
B. Relationships Between Diffusion Imaging and HASTE
with Cardiac Gating 249
IV. Signal Change in HASTE with Cardiac Gating 253
A. Signal Change and Cardiac Cycle 253
B. Velocity and Signal Change 254
C. Blood Volume and Signal Change 255
V. Clinical Applications 258
A. Potential Applications 258
B. Guidelines for Clinical Applications 260
VI. Conclusion 262
Acknowledgments 262
References 262
I. Introduction
This chapter is divided into four sections that focus on methodology: perfusion
imaging with contrast material, perfusion imaging with arterial spin labeling
(ASL), proton perfusion imaging, and gas imaging. The first three techniques
use a signal from protons. In this chapter, proton perfusion imaging is strictly
defined as a method that employs flow-related “signal change” mainly due to
dephasing of protons. While no extrinsic contrast materials are used in proton
perfusion imaging, the author will distinguish proton perfusion imaging from
ASL, which uses magnetically labeled water in blood as an endogenous, freely
diffusible contrast agent (1,2). Proton perfusion imaging of the lung parenchyma
is divided into two groups, one uses intrinsic signal change only accompanied by
cardiac contraction (3,4) while the other is based on signal change evoked by the
addition of gradients (5).
