The Concept of CMR
Slides, videos and moreEvaluating CMR
Imaging Techniques
Computed Tomography (CT)
- 1Key Points (1 page)
- 2Determining Total Adiposity With Computed Tomography (1 page)
- 3Determining Tissue Area or Mass Using CT (1 page)
- 4Measuring Skeletal Muscle Mass Using CT (1 page)
- 5Measuring Intra-abdominal Fat Using MRI and CT (2 pages)
- 6Measuring Ectopic Fat Using CT (2 pages)
- 7References (1 page)
Determining Tissue Area or Mass Using CT
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CT images are normally analyzed using one of two methods: 1) the perimeter of the tissue is traced manually (3) and the area within the perimeter is calculated by multiplying the number of pixels in the region of interest by their known area, or 2) image segmentation algorithms are used to identify all pixels within a selected range of intensities (i.e., HU) believed to be representative of a specific tissue (4). The latter method is more common when assessing CT images.
Because of the radiation involved with CT, multiple CT images are generally not acquired. However, if multiple images are acquired, tissue volumes are calculated with the same methods used for MRI images (5-8). They can then be converted to mass units by multiplying the volume by the assumed density values for that tissue (9, 10).
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