Abstract (EN):
Myocardial perfusion is commonly studied based on the evaluation of the left
ventricular function using stress-rest gated myocardial perfusion single photon emission
computed tomography (GSPECT), which provides a suitable identification of the myocardial
region, facilitating the localization and characterization of perfusion abnormalities. The
prevalence and clinical predictors of myocardial ischemia and infarct can be assessed from
GSPECT images.
Here, techniques of image analysis, namely image segmentation and registration, are
integrated to automatically extract a set of features from myocardial perfusion SPECT images
that are automatically classified as related to myocardial perfusion disorders or not. The
solution implemented can be divided into two main parts: 1) building of a template image,
segmentation of the template image and computation of its dimensions; 2) registration of the
image under study with the template image previously built, extraction of the image features,
statistical analysis and classification. It should be noted that the first step just needs to be
performed once for a particular population. Hence, algorithms of image segmentation,
registration and classification were used, specifically of k-means clustering, rigid and
deformable registration and classification.
The computational solution developed was tested using 180 3D images from 48 patients with
healthy cardiac condition and 72 3D images from 12 patients with cardiac diseases, which
were reconstructed using the filtered back projection algorithm and a low pass Butterworth
filter or iterative algorithms. The images were classified into two classes: ¿abnormality
present¿ and ¿abnormality not present¿. The classification was assessed using five
parameters: sensitivity, specificity, precision, accuracy and mean error rate.
The results obtained shown that the solution is effective, both for female and male cardiac
SPECT images that can have very different structural dimensions. Particularly, the solution
demonstrated reasonable robustness against the two major difficulties in SPECT image
analysis: image noise and low resolution. Furthermore, the classifier used demonstrated good
specificity and accuracy, Table 1.
Language:
English
Type (Professor's evaluation):
Scientific
Contact:
www.fe.up.pt/~tavares
No. of pages:
2
License type: