Non Imaging In Vivo

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Non Imaging In Vivo

• Red Cell Sequestration

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Red Cell Sequestration

• Done in conjunction with red cell survival
• Used to determine if destruction of RBCs, which
  causes shortened RBC survival, is due to splenic
  destruction of RBCs

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Procedure for RC Sequestration

• Tag blood same as for Red Cell Survival
• After 24 hour sample is drawn for Red Cell
  Survival, place patient under a thyroid probe and
  obtain counts over
• Anterior liver
• Right lateral liver
• Anterior heart (blood pool)
• Left lateral spleen
• Posterior spleen

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Procedure Continued

• Positioning probe is done by finding the area of
  the most counts over each organ.
• Once this place is located, the technologist
  needs to mark that location with a permanent
  marker.
• This ensures the same spot will be counted each
  time.
• This procedure will be repeated on the same days
  that blood is drawn for a Red Cell Survival Study
• Obtain a ratio of Liver/Spleen

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Findings

• Normal ratio is 1.0 or greater, but should be as
  close to 1 to 1 as possible
• This value should remain approximately the same
  ratio over the course of the study.
• Abnormal findings would be an increased spleen to
  liver ratio or the value steadily increases
  throughout the study.
• Splenomegally itself, without pathologic
  sequestration can yield spleen to liver ratios of
  21 or 41.
• For this reason, rising ratios are the best
  evidence of significant sequestration
• Liver disease will show a short survival time,
  but an increase in splenic counts

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