4. Transudative versus exudative ascites by ultrasonographic evaluation of gall bladder wall thickness

Liver cirrhosis with portal hypertension, various acute and chronic abdominal infections, and malignancies are common causes of ascites in our country. .As ultrasound examination is a primary radiological investigation in these patients, the ability to distinguish transudative from exudative. In this study sensitivity and specificity of ultrasound to differentiate between transudative and Exudative ascites based on gall bladder wall thickness. 50 patients referred from various clinical departments with suspected ascites or ascites diagnosed on ultrasound associated with various pathologies are included in the study during the period of two months (July-August 2004) .New generation high resolution ultrasound equipment (Echocee , Toshiba, Japan) with 3.5Mhz sector probe is used for scanning purpose. All patients with ascites are included in this study. Total ascitic fluid protein concentration of 3g% is used as gold standard which is used in our hospital to differentiate transudative from exudative ascites. Wall thickness of superior wall of gall bladder taken in all patients and 3 mm wall thickness is used as upper limit of normal in distended gall bladder . Depending on this, patients with gall bladder wall thickness > 3 mm are categorised as having transudative ascites and patients with wall thickness < 3mm as exudative ascites. As per our study, the sensitivity and specificity for determination of exudative versus transudative ascites based on gall bladder wall thickness was found to be 90.90% and 94.11% respectively and the positive predictive value and negative predictive values were estimated to be 96.77% and 84.21%. We conclude from our present study using new generation high resolution ultrasound equipment that gall bladder wall thickness in ascites can be a very useful predictive factor in differentiating transudative from exudative ascites radiologically. There is direct correlation between GB wall thickening and ascitic fluid total protein.