Differentiating Transudative From Exudative Ascites Using Quantitative B-Mode Gray-Scale Ultrasound Histogram

Area of Science:

• Medical Imaging
• Diagnostic Ultrasound
• Gastroenterology

Background:

• Ascites, the accumulation of fluid in the peritoneal cavity, is classified as either exudative or transudative.
• Differentiating between these types is crucial for determining the underlying cause and guiding treatment.
• Current diagnostic methods often involve invasive procedures like paracentesis.

Purpose of the Study:

• To evaluate the efficacy of B-mode gray-scale ultrasound histogram analysis in differentiating exudative from transudative ascites.
• To determine the diagnostic performance of the ascites-to-rectus abdominis muscle echogenicity ratio (ARAER) in this differentiation.

Main Methods:

• Prospective study of 57 patients with ascites who underwent ultrasound and paracentesis.
• Generation of gray-scale histograms from ultrasound images.
• Calculation of the ascites-to-rectus abdominis muscle echogenicity ratio (ARAER).
• Use of Receiver Operating Characteristic (ROC) curves to assess sensitivity and specificity.

Main Results:

• Significantly higher ARAER values were observed in patients with exudative ascites compared to transudative ascites (p < 0.001).
• The optimal cutoff value for ARAER was 0.002.
• The ARAER method demonstrated a sensitivity of 87.5% and a specificity of 79.2% (AUC = 0.843).

Conclusions:

• Ascites-to-rectus abdominis muscle echogenicity ratio (ARAER) is a simple, noninvasive, and quantitative ultrasound method.
• ARAER exhibits high sensitivity and specificity for distinguishing between exudative and transudative ascites.
• This sonographic technique offers a valuable tool for ascites characterization.