Hippocampal MR imaging morphometry by means of general pattern matching.
OBJECTIVE
To determine the repeatability and validity of a pattern-matching method for the segmentation and measurement of hippocampi on magnetic resonance (MR) images.


METHODS
Comparable two-dimensional MR images obtained in 18 subjects (nine healthy control subjects [six men, three women; aged 24-54 years] and nine patients with schizophrenia [six men, three women; aged 22-61 years]) were twice segmented manually and twice segmented by using pattern matching with digital atlas transformation. The atlas transformation was accomplished in two steps: global followed by local matching. Global matching was performed with use of landmarks; local matching was performed with use of a viscous fluid model.


RESULTS
The mean percentage of difference between two atlas-based measurements was 1.33% +/- 1.23 (+/- standard deviation); that between two manual measurements was 4.67% +/- 4.71. The validity of the atlas transformation measurements was demonstrated by means of the high correlation (intraclass correlation coefficient = .96) with manual segmentation measurements. Schizophrenic hippocampal areas tended to be smaller; however, no differences in hippocampal shape were found between patients with schizophrenia and patients with control subjects.


CONCLUSIONS
General pattern matching of a digital brain atlas to an individual MR image is a mathematically robust method of measurement that is reproducible and less variable than manual measurement.
Haller
J W
JW
Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110, USA.
Christensen
G E
GE
Joshi
S C
SC
Newcomer
J W
JW
Miller
M I
MI
Csernansky
J G
JG
Vannier
M W
MW
D000328:Adult; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010363:Pattern Recognition, Automated; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000175:diagnosis