Scintigraphic determination of equivocal appendicitis.

Area of Science:

• Nuclear Medicine
• Immunoscintigraphy
• Diagnostic Imaging

Background:

• Acute appendicitis diagnosis can be challenging in equivocal clinical presentations.
• Current diagnostic methods may have limitations in sensitivity and specificity.
• Novel imaging agents are needed for improved diagnostic accuracy.

Purpose of the Study:

• To evaluate the safety and efficacy of Tc-99m-labeled anti-CD15 immunoglobulin M monoclonal antibody (LeuTech) for scintigraphic detection of acute appendicitis.
• To assess the sensitivity, specificity, and predictive values of LeuTech imaging in patients with equivocal appendicitis.
• To determine the time course of image positivity for acute appendicitis using LeuTech.

Main Methods:

• A study involving 99 patients with equivocal clinical presentations for appendicitis.
• Intravenous administration of 10 to 20 mCi of Tc-99m LeuTech.
• Serial dynamic and static planar imaging acquired up to 3 hours post-injection.
• Institutional diagnosis confirmed by surgery, histopathology, or clinical follow-up.

Main Results:

• LeuTech imaging demonstrated high sensitivity (98%) and specificity (84%) for acute appendicitis.
• Overall accuracy was 90%, with a positive predictive value of 81% and negative predictive value of 98%.
• Positive scans for appendicitis were observed rapidly, with a mean time to first positive image of 15 minutes and all positive by 1 hour.

Conclusions:

• LeuTech imaging is a highly sensitive and accurate diagnostic test for acute appendicitis in patients with equivocal presentations.
• The agent offers advantages in convenience and speed of diagnosis compared to other radiotracers.
• No serious adverse reactions were reported, indicating a favorable safety profile.