Because of evidence based medicine principles introduction into practice, requirements to hardware diagnostic methods have increased. Accurate information about presence of pathological changes in surrounding tissues and organs, related to biliary obstruction, must be provided. Application of three-dimensional virtual NLS-diagnostics modes allows to specify accurately the amount of tumorous affection, its interrelation with surrounding vessels and bile ducts, intensity of invasion into surrounding tissues.

    NLS-symptoms of tumorous lesion included direct symptoms, when tumor itself is visualized – a solitary nidus of heterogeneous structure, with different (decreased mainly) chromogeneity, with a line of demarcation between a tumor and surrounding normal tissue. Application of ultrasound research methods usually visualizes tumors of 10 mm and larger. Three-dimensional NLS-ultramicroscanning mode with spectral-entropic analysis allows to diagnose tumors sized 1mm and lesser.

    Tumors of distal bile-excreting ducts and major duodenal papilla due to tumorous invasion, circular squeezing and growth into a lumen of a duct may cause an obstruction. At the same time indirect symptoms of biliary obstruction are registered: dilation of proximal areas of bile ducts; enlargement of gall bladder; development of hepatic changes, typical for hepatic secretory obstruction. At accompanying obstruction of main pancreatic duct directly at the point of transition to ampoule, a dilation of a duct is detected distal to obstruction level.

    Application of three-dimensional virtual NLS-diagnostics with metatron 4025 hunter allowed to increase sensitivity up to 100%, specificity – up to 97% in comparison with a standard ultrasound research. Application of CT at the absence of a significant dilation of bile-excretory ducts had lesser diagnostic value (sensitivity – 66.7%, specificity – 93.5%).