Objective To investigate the detection rate and diagnostic value of multi-slice spiral CT scan in detecting fish bone impaction in the esophagus.Methods Experimental group: 30 fresh water fish bones from three variety classes were divided into three groups with length of(23.36±0.15), (28.51±0.07) and (30.89±0.10) mm, and diameter of (4.49±0.31), (1.78±0.09) and (0.49±0.07) mm.The fish bones were put into esophagus models in three different types including parallel, perpendicular and oblique.MSCT with axial scan combined with three dimensional reconstruction technique and plain X-ray film (CR and DR) were used to examine the model.The relations of the number and rate of fish bones were compared between MSCT and X-ray film.Clinical group: MSCT imaging were performed in 20 cases proved by esophageal endoscope or clinical operation, among which 11 cases received plain X-ray film (CR and DR), 15 cases received Barium-soaked cotton and 17 cases received endoscope.Paired Chi-square test was used to compare the differences of detection of fishbone by the different ways.Results In experimental group: All the 90 cases(100%) fish bones of three different species were clearly revealed on MSCT image; only 60 cases(66.7%) fish bones were revealed by plain X-ray film(CR and DR).The number and rate of fish bones detected by MSCT was higher than that of plain X-ray film (CR and DR) (X2=28.03, P < 0.01).In clinical group: 20 cases were made right diagnosis by MSCT, and the location and size of fish bone in the esophagus, the surrounding and complications of esophagus could be clearly demonstrated on MSCT image.Two cases detected by plain X-ray film(CR and DR) ;9 cases detected by Barium-soaked cotton;14 cases detected by endoscopy.The number and rate of fish bones detected by MSCT was higher than that of plain Xray film (CR and DR) (X2=7.11, P < 0.05) and Barium-soaked cotton (X2=4.17, P < 0.05).Conclusions The sensitivity and detection rate of fish bone with MSCT was high and could evaluate the surrounding and complications of the esophagus.MSCT could be used as the first examination of impacted fish bones in the esophagus.