Siêu âm nội soi cũng có thể được sử dụng giai đoạn ung thư tuyến tụy, nhưng độ chính xác cần đánh giá thêm [2]. Kỹ thuật này cũng chính xác cao cho địa phương hóa các các khối u tuyến tụy thần kinh nội tiết thường không nhìn thấy bằng các phương pháp khác | Imaging of the Biliary Tract Interventional Radiology and Endoscopy 567 Fig. . Endoscopic ultrasound in a patient with suspected neuroendocrine tumour in whom CT scan had shown no abnormality. cm diameter mass shown in head of pancreas PD pancreatic duct SV superior mesenteric vein. Courtesy of Dr Steve Pereira. tumour 93 than CT 53 52 . Endoscopic ultrasound may also be used to stage pancreatic cancer but its accuracy needs further evaluation 2 . This technique is also highly accurate for localizing pancreatic neuroendocrine tumours which are often not well seen by other methods fig. 6 . Endoscopic ultrasound-guided fine-needle aspiration biopsy is possible from lymph nodes and pancreatic lesions and in experienced hands is safe 75 . With the increased availability of this technique it is being used more frequently for the evaluation of patients with pancreatic tumours in particular for biopsy and assessing resectability. It may also be valuable for patients with problematic biliary tract pain where MRCP and other scanning has been negative and ERCP unhelpful. Endoscopic ultrasound to look for tiny bile duct stones and for pancreatic disease may be clinically indicated in combination with endoscopic biliary manometry. Biliary scintigraphy The technetium-labelled iminodiacetic acid derivative IDA is cleared from the plasma by hepato-cellular organic anion transport and excreted in the bile fig. . Biliary radiopharmaceuticals have so improved that one of the newest Iodida is easily prepared and is taken up by the liver and excreted into bile efficiently with only 5 of the injected dose excreted in the urine. Effective concentration in the bile duct is achieved in patients with total serum bilirubin levels exceeding 340 pmol l 20 mg dl . Resolution is much less than with other forms of bile duct visualization and the role of cholescintigraphy is therefore limited. The method may be used to determine patency of the cystic duct in suspected acute .
