Inflammation: imaging with Tc-99m HMPAO-labeled leukocytes

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Immunology

Background:

• Leukocyte scintigraphy is crucial for diagnosing inflammatory and infectious diseases.
• Technetium-99m hexamethylpropyleneamine oxime (Tc-99m HMPAO) offers advantages for radiolabeling leukocytes.
• Previous studies utilized indium-111 labeled leukocytes, necessitating comparison with newer Tc-99m agents.

Purpose of the Study:

• To evaluate the diagnostic utility of Tc-99m HMPAO-labeled leukocytes in a diverse patient cohort.
• To assess the sensitivity and specificity of this method for detecting inflammation.
• To characterize the biodistribution and migration patterns of Tc-99m HMPAO-labeled leukocytes.

Main Methods:

• 100 patients with suspected inflammatory or infectious conditions underwent imaging with Tc-99m HMPAO-labeled leukocytes.
• Imaging included early (1-3 hours) and late (24 hours) views.
• Activity distribution and granulocyte migration were analyzed and correlated with clinical diagnoses.

Main Results:

• Tc-99m HMPAO-leukocyte imaging demonstrated 100% sensitivity and 95% specificity for inflammation detection.
• Observed activity in kidneys, bladder, and gallbladder differed from indium-111 labeled leukocyte studies.
• Early granulocyte migration (30 minutes) indicated inflammation, distinct from later normal bowel activity (4 hours).

Conclusions:

• Tc-99m HMPAO-labeled leukocytes are highly sensitive and specific for detecting inflammation.
• The imaging agent exhibits a distinct biodistribution pattern compared to older agents.
• This technique provides valuable diagnostic information for various clinical indications.