IMAGE COMPARISON OF REAL-TIME GRAY-SCALE ULTRASOUND AND COLOR DOPPLERULTRASOUND FOR USE IN DIAGNOSIS OF MINIMAL PLEURAL EFFUSION

To assess the value of color Doppler ultrasound in distinguishing mini mal pleural effusion from pleural thickening, a prospective analysis w as done on the ultrasonographic findings in 51 patients. Real-time, gr ay-scale, and color Doppler chest ultrasound examinations were carried out by different sonographers who had no clinical information concern ing the patients. The sonographer evaluated the images for internal ec hogenicity of the effusion, pleural lesions that change shape with res piration, and movable septa and echo-densities in pleural space in con ventional gray-scale as well as color signal in color Doppler ultrasou nd. Of the 35 patients with true effusion, 33 had positive color signa l (sensitivity 94.3%, 95% confidence intervals [Cl] 89 to 98.6%); in 1 6 patients without effusion, none had color signal (specificity 100%, 95% Cl 83 to 100%). Although real-time, gray-scale ultrasound is also sensitive for detecting minimal effusion (sensitivity 100%, 95% Cl 92 to 100%), it is less specific (specificity 68.7%, 95% Cl 46 to 91.5%). Five of 16 examinations showing fluid-like lesions were found to be d eceptive. With relatively high sensitivity and specificity, this metho d proved to be a useful diagnostic aid to real-time, gray-scale ultras ound for diagnosis of minimal or loculated effusion.