An Application of Image Processing Techniques in Computed Tomography Image Analysis

Abstract

An estimate of the thickness of subcutaneous adipose tissue at differing positions around the body was required in a study examining body composition. To eliminate human error associated with the manual placement of markers for measurements and to facilitate the collection of data from a large number of animals and image slices, automation of the process was desirable. The open-source and free image analysis program ImageJ was used. A macro procedure was created that provided the required functionality. The macro performs a number of basic image processing procedures. These include an initial process designed to remove the scanning table from the image and to center the animal in the image. This is followed by placement of a vertical line segment from the mid point of the upper border of the image to the image center. Measurements are made between automatically detected outer and inner boundaries of subcutaneous adipose tissue along this line segment. This process was repeated as the image was rotated (with the line position remaining unchanged) so that measurements around the complete circumference were obtained. Additionally, an image was created showing all detected boundary points so that sites of measurement could be checked by visual inspection. This paper provides a detailed account of this macro, illustrates the effect of its components on the image, and the applicability of standard image processing techniques to veterinary imaging.

Late gestation undernutrition can predispose for visceral adiposity by altering fat distribution patterns and increasing the preference for a high-fat diet in early postnatal life

“…Histograms showing the frequency of occurrence of each CT number (measured in Hounsfield units) in all image slices were used to determine the relative proportions of image pixels that displayed adipose tissue to those that displayed non-adipose soft (lean) tissue as reported previously ( 34 ) . Semi-automated image analysis techniques described previously ( 35 ) were used to determine the thickness of subcutaneous adipose tissue on particular image slices.…”

External infiltrating lipoma in a two‐week‐old foal: Computed tomographic evaluation for the assessment of the extension and invasiveness of the tumour

“…The advantage of MRI over CT in having a better soft tissue contrast resolution would not have helped in this case. It is accepted that CT is a good modality for the assessment of body fat (Ishioka et al 2005;McEvoy 2007). The limiting factor for CT scans in horses is the size of the patient.…”

Computer tomographic investigation of subcutaneous adipose tissue as an indicator of body composition

“…CT images are essentially digital maps of the linear attenuation coefficient for x-rays, displayed voxel by voxel. There are many examples in the literature of different automation strategies using CT images [ 15 , 16 ] and also in other cross sectional imaging modalities [ 17 ]. The algorithm used in this study was written to produce measurements that mimic those obtainable by ultrasound.…”