Splenic haematocrit and the splenic plasma pool

Area of Science:

• Nuclear Medicine
• Hematology
• Medical Imaging

Background:

• Accurate assessment of plasma volume and splenic function is crucial in hematological disorders.
• Splenomegaly can significantly impact these measurements, necessitating reliable quantification methods.

Purpose of the Study:

• To establish and validate a quantitative scanning method for estimating plasma volume and splenic plasma pool.
• To assess the splenic red cell pool and splenic hematocrit in patients with hematological disorders and splenomegaly.

Main Methods:

• Utilized 113mIn-labelled transferrin (TF) for quantitative scanning.
• Applied the method to 12 patients with diverse hematological conditions and varying degrees of splenomegaly.
• Compared results with the standard 125I human serum albumin (HSA) method for plasma volume estimation.

Main Results:

• 113mIn-TF consistently overestimated plasma volume by approximately 6% compared to the 125I HSA method.
• The splenic plasma pool ranged from 1.2% to 11.4% of total plasma volume.
• Calculated splenic hematocrit (SHct) averaged 0.51, with ratios of SHct/PCV and SHct/body Hct of 1.21 and 1.30, respectively. SHct was independent of PCV and body Hct, but tended to decrease with increased splenomegaly.

Conclusions:

• The 113mIn-TF method provides a reliable means to estimate plasma volume and splenic plasma pool.
• Direct measurement of the splenic plasma pool may offer insights into the causes of increased total plasma volume in patients with hematological disorders.
• Quantification of splenic hematocrit is feasible and provides valuable information regarding splenic function in these conditions.