Size of cortical bone and relationship to bone mineral density assessed by quantitative computed tomography image segmentation.
OBJECTIVE
The accuracy of the measurement of the size of cortical bone on computed tomography (CT) images of human vertebrae was evaluated using an automated contour detection and segmentation procedure.


METHODS
Forty human lumbar vertebrae were scanned using 8-mm slices and an automated detection for definition of trabecular and cortical region of interest. The vertebrae were embedded in a polyester resin and 8-mm-thick midvertebral specimens were excised using a diamond circular saw. Contact radiographs of these specimens were performed and, after photograph magnification, the cortical area was measured using computerized planimetry.


RESULTS
Cortical area measured on CT images was highly correlated with the area measured by planimetry on the specimens (r = .91; P < .001) with, however, a systematic over-estimation. A significant relationship was found between density and width of the cortex (r = .56; P < .001).


CONCLUSIONS
Computed tomography is able to assess the size of cortical bone in human vertebrae, but a threshold detection algorithm, as used in the current study, is not adequate to obtain the precise anatomic dimensions.
Louis
O
O
Department of Radiology, Vrije Universiteit Brussel, Belgium.
Van den Winkel
P
P
Covens
P
P
Schoutens
A
A
Osteaux
M
M
D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D014057:Tomography, X-Ray Computed