Biomedical Engineering Reference
In-Depth Information
7
Registration and Subtraction of Serial
Magnetic Resonance Images of the Brain:
Image Interp
retation and Clinical Applications
Angela Oatridge, Joseph V. Hajnal, and Graeme M. Bydder
CONTENTS
7.1
Introduction ................................................................................................ 144
7.2
Methods....................................................................................................... 145
7.3
Image Interpretation—General ................................................................ 147
7.4
Interpretation and Registered Subtraction Images ............................... 149
7.4.1
Interpretation of Pure Changes in Signal Intensity................... 149
7.4.2
Interpretation of Pure Changes in Site, Shape, or Size ............. 151
7.4.2.1
Model for Analyzing Shifts............................................ 151
7.4.2.2
Effect of Signal Intensity Gradient Size ....................... 152
7.4.2.3
Effects of Signal Intensity Gradient Direction ............ 153
7.4.2.4
Effects of Size of Shift ..................................................... 154
7.4.2.5
Effects of Shift Direction................................................. 154
7.4.2.6
Effects of Change in Shape (without Change
in Signal Intensity) .......................................................... 158
7.4.2.7
Effect of Change in Size (without Change
in Signal Intensity) .......................................................... 158
7.4.2.8
Etiology............................................................................. 159
7.4.3
Interpretation of Changes in Signal Intensity Combined
with Changes in Site, Shape, or Size on Difference Images. .... 160
7.5
Regional and Tissue-Specific Appearances on Difference Images...... 161
7.5.1
The Ventricular System ................................................................. 161
7.5.2
The Brainstem and Cerebellum ................................................... 162
7.5.3
The Cerebral Cortex....................................................................... 162
7.5.4
Global Change in Brain Size ......................................................... 162
7.5.5
Blood Vessels and Venous Sinuses .............................................. 163
7.5.6
Meninges ......................................................................................... 163
7.5.7
Other Extracerebral Tissues and Fluids ...................................... 163
7.6
Artifacts and Failed Registration ............................................................. 164
