Quantification of small cerebral ventricular volume changes in treated
growth hormone patients using non-rigid registration
IEEE Trans. Med. Imaging (in press)
Julia A. Schnabel
Derek L.G. Hill,
Radiological Sciences, GKT, Guy's Hospital,
London, SE1 9RT, UK.
Non-rigid registration can automatically quantify small changes
in volume of anatomical structures over time by means of
segmentation propagation. Here we use a non-rigid
registration algorithm based on optimising normalised mutual
information to quantify small changes in brain ventricle volume in MR
images of a group of five patients treated with growth hormone
replacement therapy and a control group of six volunteers.
The lateral ventricles are segmented from each subject image by
registering with the brainweb image [Collins98]
which has this structure delineated.
The mean (standard deviation) volume change measurements are
1.09 (0.73) cm3
for the patient
group and 0.08 (0.62) cm3
for the volunteer
group; this difference is
statistically significant at the 1% level.
We validate our volume measurements by determining the
precision from three consecutive scans of five volunteers and also comparing
the measurements to previously
published volume change estimates obtained by visual inspection of difference images.
Results demonstrate a precision (standard deviation)
(n=5) and a rank correlation coefficient with assessed difference images of
To determine the level of shape correspondence we manually segmented
subject's ventricles and compared them to the propagations
using a voxel overlap similarity
index, this gave a mean similarity index of 0.81 (n=7).
draft submission in pdf
Mark Holden |
firstname.lastname@example.org Last modified: 30 Aug, 2002.