OBJECTIVE: The purpose of this study was to determine the optimal time for obtaining delayed images with contrast-enhanced CT in @entity1 who have @entity1419 . SUBJECTS AND METHODS: CT studies were performed in 25 consecutive @entity1 with proven @entity201 , including six @entity1 who had undergone radiotherapy or chemotherapy. Dynamic images of the liver were obtained after 150 ml of IV contrast material was administered at 3 ml/sec. Delayed CT images were then obtained at 10, 20, and 30 min. @entity96 attenuation difference was determined quantitatively for each time period. Images were qualitatively evaluated by three observers for attenuation of the @entity5 (hypoattenuating, isoattenuating, or hyperattenuating) relative to the liver. Observer confidence for @entity5 detection was graded on a four-point scale. Dynamic and delayed images were compared for @entity5 conspicuity. RESULTS: On dynamic images, 18 @entity5 (72%) were hypoattenuating, six (24%) were isoattenuating, and one was heterogeneous. On delayed images, 15 (60%) of these 25 @entity5 were isoattenuating and nine (36%) were hyperattenuating compared with the liver. @entity96 attenuation difference was greatest on dynamic studies (p < .01) and did not differ significantly among the three delay times (p > .20). All @entity5 seen on delayed images were also seen on dynamic images; however, in three @entity1 (12%), the confidence level for presence of @entity5 was better on delayed than on dynamic images. Confidence levels for presence of @entity5 did not vary significantly among the three delay times. Attenuation values on dynamic and delayed images did not differ for the groups of @entity1 who had or had not undergone prior radiotherapy or chemotherapy (p > .05). CONCLUSION: In the evaluation of hilar or @entity1419 , delayed CT images are helpful for @entity5 characterization and may improve observer confidence for the presence of @entity5 . The optimal time for acquisition of delayed images is 10-20 min after contrast media injection.

Contrast-enhanced CT of intrahepatic and XXXX : delay time for optimal imaging.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity96 :: ('MESH:D008113', 'Disease') :: ['Tumor-liver'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'tumors'] @entity201 :: ('MESH:D018281', 'Disease') :: ['cholangiocarcinoma'] @entity1419 :: ('MESH:C535533', 'Disease') :: ['intrahepatic or hilar cholangiocarcinoma', 'intrahepatic cholangiocarcinoma']
@entity201 :: (MESH:D018281,Disease) :: ['hilar cholangiocarcinoma']
