Abstract
Purpose
To systematically compare two techniques for measuring brain atrophy rates from serial magnetic resonance imaging (MRI) studies.
Materials and Methods
Using the separation in atrophy rate between cohorts of cognitively normal elderly subjects and patients with Alzheimer's disease (AD) as the gold standard, we evaluated 1) different methods of computing volume change; 2) different methods for steps in image preprocessingโintensity normalization, alignment mask used, and bias field correction; 3) the effect of MRI acquisition hardware changes; and 4) the sensitivity of the method to variations in initial manual volume editing. For each of the preceding evaluations, measurements of wholeโbrain and ventricular atrophy rates were calculated.
Results
In general, greater separation between the clinical groups was seen with ventricular rather than wholeโbrain measures. Surprisingly, neither the use of bias field correction nor a major hardware change between the scan pairs affected group separation.
Conclusion
Atrophy rate measurements from serial MRI are candidates for use as surrogate markers of disease progression in AD and other dementing neurodegenerative disorders. The final method has excellent precision and accurately captures the expected biology of ADโarguably the two most important features if this technique is to be used as a biomarker of disease progression. J. Magn. Reson. Imaging 2003;18:16โ24. ยฉ 2003 WileyโLiss, Inc.