Abstract: Based on the in-vitro study, 3 patients with hemorrhagic cholecystitis were diagnosed preoperatively and hemorrhagic cholecystitis can be subdivided into mixed and non-mixed types. In-vitro experiments show that 0.2mL of blood in 10mL of bile could be detected as a hyperintense area on T₁-weighted image, 0.4mL of blood on proton density weighted image as a slightly hyperintense area if the blood was hot mixed with bile. T₂ weighted image was found insensitive in detecting blood in the bile. If the blood mixed with bile completely it increased the sighal intensity of the bile uniformly on all the MR images.
The MRI appearance of non-mixed hemorrhagic cholecystitis is pathognomonic, on T₁-and proton density-weighted images in the gallbladder there is (are) hyperintense area(areas), on T₂-weighted image the area(areas) is (are) isointinse or hypointense in its center and hyperintense in its periphery relative to the surrounding bile. The MRI appearance of mixed hemorrhagic cholecystitis is that relative to the liver, the signal intensity of gallbladder contents is uniformly high on all the MR images. This type of hemorrhagic cholecystitis can be diagnosed with reference of clinical finding and gallbladder wail and pericholecystic effusion.

Key words: MRI, Gallbladder, Hemorrhagic cholecystitis