[Visual evaluation of liver function with 99mTc-GSA scintigraphy: interobserver variation and intraobserver...

Area of Science:

• Nuclear Medicine
• Hepatology
• Diagnostic Imaging

Background:

• Assessing liver function is crucial for managing liver diseases.
• Current methods for evaluating liver function can be invasive or lack precision.
• Technetium-99m galactosyl human serum albumin (99mTc-GSA) scintigraphy is a potential tool for non-invasive liver function assessment.

Purpose of the Study:

• To introduce and validate a novel imaging grade for assessing liver function using 99mTc-GSA.
• To evaluate the diagnostic utility of this new grading system through interobserver and intraobserver variation analysis.

Main Methods:

• 104 patients with liver disease received 185 MBq/3 mg of 99mTc-GSA.
• Anterior cardiac blood-pool and liver images were acquired 5 minutes post-injection.
• Images were classified into four grades (I-IV) based on the relative appearance of cardiac blood-pool and liver.
• Three radiologists independently assessed images twice, with a 3-month interval.
• Kappa-test was used to determine interobserver and intraobserver agreement.
• Quantitative indices from time-activity curves and plasma retention rate of indocyanine green were analyzed.

Main Results:

• Excellent interobserver agreement (mean kappa = 0.88) and intraobserver agreement (mean kappa = 0.87) were achieved.
• Significant differences in quantitative indices were observed across the four imaging grades.
• The imaging grade showed a significant difference in plasma retention rate of indocyanine green between grade II and grade III.

Conclusions:

• The proposed 99mTc-GSA imaging grade demonstrates high reliability and reproducibility.
• This grading system offers a valuable, non-invasive method for discriminating liver function.
• The imaging grade shows excellent agreement among radiologists, supporting its clinical utility.