MR quantification of cerebral ventricular volume using a semiautomated algorithm.
OBJECTIVE
A semiautomated border identification algorithm, insensitive to user bias, is evaluated for accuracy and speed in the measurement of ventricular volumes from three-dimensional MR images.


METHODS
A three-dimensional gradient-echo technique was implemented on a Signa clinical imaging system. Data from phantoms and patients were analyzed for volume using a segmentation algorithm designed with: 1) correction for partial volume averaging; 2) insensitivity to user bias; and 3) speed. Accuracy, precision, and intra- and interobserver variability were determined.


RESULTS
Average error for phantom studies was 4% to 6%, or 1 to 2 cc across the volumes, which ranged from normal to mild hydrocephalus (< 60 cc). Patient studies showed intra- and interobserver error of 2.3% and 7.8%, respectively. The correction for partial volume averaging resulted in a threefold decrease in error. Data were acquired and reconstructed within 7 minutes. Experienced radiologists required less than 15 minutes to perform each analysis.


CONCLUSIONS
This algorithm allows accurate measurement of ventricular volumes in an efficient, minimally supervised manner.
Johnson
L A
LA
Nuclear Magnetic Resonance Center, Massachusetts General Hospital, Charlestown 02129.
Pearlman
J D
JD
Miller
C A
CA
Young
T I
TI
Thulborn
K R
KR
D000328:Adult; D000368:Aged; D002552:Cerebral Ventricles / Q000033:anatomy & histology* / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008961:Models, Structural; D015588:Observer Variation