RELATIVE ACCURACY AND REPRODUCIBILITY OF REGIONAL MRI BRAIN VOLUMES FOR POINT-COUNTING METHODS

Volumetric magnetic resonance imaging (MRI) methods for the measuremen t of various neuroanatomical regions are of great interest in studies of neuropsychiatric disorders. Both manual and semiautomated methods h ave been developed. Manual methods include tracing and point counting. Point-counting methods are widely used in post-mortem and microscopy studies. Point counting has been well validated for these purposes. In this article, we report in a series of separate studies the accuracy and reproducibility of point-counting methods. Absolute accuracy was e valuated with a spherical phantom. Accuracy and time efficiency were s ubsequently assessed with an anatomically realistic phantom and variou s size grids. The point-counting method was also compared to a tracing method. Finally, the reproducibility of the point-counting method for the caudate and putamen was evaluated on four subjects in a test-rete st experiment. These studies provide an estimate of the accuracy and t ime efficiency of point-counting methods. The test-retest reliability was also high for both caudate and putamen. Findings suggest that poin t counting is a reliable and efficient method for estimating volumes.