Electron Beam Computed Tomography

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Electron Beam Computed Tomography

• Yan Pan
• Department of Biomedical Engineering
• The University of Iowa, Iowa City, IA 52242
• Email yan-pan_at_uiowa.edu
• Oct 5,2004

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Outline

• What is EBCT?
• EBCT vs. Conventional CT, Multi Slice CT, Helical
  CT
• EBCT in heart disease
• EBCT in lung disease
• EBCT Colonography
• EBCT in the future

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Electron Beam CT

• It operates by means of a focused electron beam
  which is magnetically directed at the speed of
  light across one to four tungsten target rings,
  positioned beneath the patient. Each target
  generates two beams of photons. Each 210 degree
  "sweep" of the electron beam produces a
  continuous 30 degree fan beam of x-rays that pass
  through the patient to a semicircular (180) array
  of detectors. This information generates the
  cross sectional images.

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EBCT scan
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Benefits

• Painless, safe, non-invasive
• Open, non-claustrophobic machine
• Considerably lower doses of radiation compared to
  traditional scanning
• Produces images of the body at unprecedented
  speeds, 10 times faster than a conventional CT
  scanner
• Accurate high resolution, as detailed as 0.7mm
• Its the only technology approved by the FDA for
  Calcium Scoring due to image accuracy and
  sensitivity to Calcium. Its the only imaging
  technology which enables coronary Calcium to be
  accurately measured and monitored by subsequent
  EBCT scans to check if the treatment is working
• Its the gold standard for quantification of
  coronary Calcium

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EBCT in Heart Disease Detection

• CAD
• Coronary artery disease (CAD) is a condition
  that obstructs the flow of blood in the arteries
  in and around the heart. It is the leading cause
  of death in United States. The most common cause
  of CAD is atherosclerosis, an accumulation of
  material known as plaque, in the coronary
  arteries that supply the heart with blood.

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• The short exposure time for EBCT allows clear,
  computerized, three-dimensional images of moving
  body parts to be taken. It can very accurately
  identify and quantify the presence or absence of
  calcium deposits, both in or around the coronary
  arteries. The amount of calcium in the coronary
  arteries has been found to be a marker for the
  presence of coronary artery disease.

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Coronary Artery EBCT Images
a
c
b

• Significant calcification in the coronary
  arteries, indicating advanced
• coronary artery disease
• b. Mild calcification early stages of CAD
• c. Normal coronary arteries - no calcification

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Stroke

• Stroke---disease that affects the blood vessels
  that supply blood to the brain. A stroke occurs
  when a blood vessel that brings oxygen and
  nutrients to the brain bursts or is clogged by a
  blood clot or some other mass.
• Calcification present in blockages of the heart
  arteries is linked to an increased risk of
  stroke. The most common type of stroke is caused
  by blockages in blood vessels. Study shows that
  people who experience stroke have higher amounts
  of calcium in their coronary arteries.
• EBCT, which can detect the density of calcium
  deposits, is used to detect the risk of stroke.

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EBCT in Lung Disease Detection

• Cystic Fibrosis
• Identify regional changes and distribution of
  airway disease, and differentiate transient from
  irreversible airway and lung tissue changes.
• lung cancer screening
• An accurate, non-invasive and painless
  procedure which provides quantitative measures of
  lung health that can not be obtained from
  conventional tests. EBCT is so sensitive that can
  detect abnormalities, such as lung nodules,
  growths and emphysema, which have not yet
  produced any obvious symptoms.

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EBCT scan for the lung
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EBCT Colonography (virtual colonoscopy)

• The virtual colonoscopy, a new state-of-the-art
  Colon Cancer screening technique, which is
  comparatively noninvasive procedure, gives
  physicians a computerized, 3-D look at the colon,
  making polyps and cancer detection quick and
  pain-free. A virtual colonoscopy is safer,
  quicker and much more comfortable than the
  conventional colonoscopy and it requires no
  sedation or hospital stay

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3D image of the colon Small polypoid
lesion of the distal colon
Fly-through technology showing EBT virtual
colonoscopy
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Limitation of EBCT

• Compare to other image modalities (i.e. MRI),
  chief disadvantage associated with EBCT is its
  use of ionizing radiation, which limits the
  number of scans considered safe
• EBCT is not recommended to diagnose obstructive
  CAD
• the poorer spatial resolution and modest
  longitudinal scan range limit the performance of
  EBCT angiography.
• Also EBCT is not currently covered by insurance,
  and costs approximately 400.

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EBCT Future

• 2-D Array Detector for 4D EBCT
• 1-1.5 mm thick sections
• 100-300 contiguous slices with 50msec scan
  aperture
• 10 line pair per cm resolution
• Upright body posture scanning

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Thanks