The ultrasound findings of 100 patients with chloedocholithiasis documented by cholangiography and/or surgery were reviewed retrospectively. Common duct stones were detected in 45% of patients. This detection rate which is comparable with most series confirmed the lack of reliability of ultrasound in the diagnosis of choledocholithiasis. All the stones detected were in dilated common ducts. The main limiting factor was overlying bowel gas which impair visualisation of the lower part of the common duct. Despite the apparent insensitivity of ultrasound to detect common duct stones, the modality is still a valuable non-invasive screening diagnostic tool, because in positive cases, patients may be spared from invasive cholangiographic procedures.
Stones in the biliary tract are routinely identified using MRCP (magnetic resonance cholangiopancreatography). The noisy nature of the images, as well as varying intensity, size and location of the stones, defeat most automatic detection algorithms, making computer-aided diagnosis difficult. This paper proposes a multi-stage segment-based scheme for semi-automated detection of choledocholithiasis and cholelithiasis in the MRCP images, producing good performance in tests, differentiating them from "normal" MRCP images. With the high success rate of over 90%, refinement of the scheme could be applicable in the clinical environment as a tool in aiding diagnosis, with possible applications in telemedicine.