ABSTRACT
How to eliminate the background of other tissue and to protrude the blood vessel information is the basic requirements in DSA. Because of the complexity and non-linearity of the X-ray imaging process, the common DSA technique cannot completely remove other tissue's image which lapped over the vessels. By experiments, this paper analyses and corrects the imaging process of the actual DSA system based on the "equivalent single energy" model, and the results indicate the validity of this method.
Subject(s)
Angiography, Digital Subtraction , Image Processing, Computer-Assisted , Radiographic Image Enhancement , Algorithms , Aluminum , Angiography, Digital Subtraction/methods , Humans , Image Processing, Computer-Assisted/methods , Plastics , Radiographic Image Enhancement/methods , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
AIM:To study the relationship between pre-formation of gallstone and the kinetics and ultra-structure of sphincter of Oddi.METHODS:Adult female rabbits were used and divided into 3 groups,and fed with either normal or high cholesterol diet for four or eight weeks.Each group contained eight rabbits. The manometry of sphincter of Oddi, biliary cineradiography, gallbladder volume measurement and ultrastructure observation under electron microscope were performed.RESULTS:In groups I and II,the basal pressure in low-pressure ampulla or high pressure zone of sphincter of Oddi was elevated,the amplitude of phasic contraction was decreased and the volume of gallbladder were increased, with a significant difference (P < 0.01) from those of control. Gallstones were found in group II rabbits (7/8). Under cineradiography, low-pressure ampulla showed a spasmodic status without apparent peristaltic contraction. Under electron microscope, inside the muscular cells of sphincter of Oddi, loosening of micro filament and swelling of plasmosomes which congregated at the top were observed. The amount showed no obvious change under nitric oxide synthase (NOS) stain.CONCLUSION:Twisting of the microfilament and disarrangement of kink macula densa inside the muscular cells suggested that the sphincter of Oddi was under spasmodic status. The impaired diastolic function caused and aggravated the stasis of cystic bile. The swelling plasmosome could be one of the important factors in elevating the tonic pressure of sphincter of Oddi.
