CT study of muscle

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CT study of muscle

• Bioengineering 297
• Friday, November 04, 2005
• Thomas Lang
• Thomas.Lang_at_radiology.ucsf.edu

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Outline

• Focus on muscle CT in epidemiologic studies
• Acquisition and processing
• Measurements at abdomen and thigh
• Variables measured

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Measurements of interest

• Muscle cross-sectional areas
• Associated with muscle strength
• Declines with age (15 per decade in men)
• Associated with testosterone levels
• Muscle hounsfield unit
• Related to sub-resolution fatty infiltration,
  muscle quality
• In thigh and trunk related to muscle strength and
  physical performance in elderly
• In trunk, related to lower back pain in elderly
• Intramuscular fat depots
• Increases with age
• Associated with insulin resistance and other
  metabolic abnormalities

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Abdomen L4-L5 IV space
140 kVp, 300-360 mAs, 10-mm slice thickness
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Image information
Fat depots 1)subcutaneous 4)visceral
Muscle 2) Rectus abdominus 3) Lateralis
abdominus 5) Psoas 6) Erector Spinae
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Muscle/fat segmentation in abdomen
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1
3
4
5
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• Visceral compartment 2) outer abdominal wall
• 3) Psoas 4)erector spinae 5)Lateralis abdominus
• 6) Aorta and rectus abdominus

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Segmentation of abdominal CT
Automated region growing-outer body
contour Fat/lean segmentation based on lean HU
intervals derived From histogram of fat/lean
tissue in scan or phantom
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Femoral shaft
120 kVp 200-250 mAs, 10-mm slice thickness
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This line is sometimes prominent and represents
tendon of gluteus maxius muscle shall it belong
somewhere?
Quadriceps
adductors
Biceps femorissemitendinosoussemimembranosousha
mstrings
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Muscle segmentation in thigh
Manual Hamstring, quadriceps, sartoris,
intramuscular fat Automated Outer thigh
contour Subcutaneous fat Total muscle area
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Thigh Segmentation