Experimental Microangiographic Study in Normal Rabbit Liver

PURPOSE: Microangiography is an experimental radiologic technique for evaluation of the morphology and the function of small vessels. The purpose of this study is to introduce a good microangiographic technique and to present the microangiographic appearance of normal hepatic vascular pattern. MATERIALS AND METHODS: Five white rabbits weighing 2.5-2.9Kg were objected. Polyethylene catheters were inserted in portal vein and then in IVC. Heparin mixed normal saline (2cc/1000cc) was infused through portal vein and blood was drained to IVC. Barium suspension was infused via the catheter placed in portal vein untill the liver surface showed satisfactory finding in barium filling. The liver was removed and this preparation was fixed in 10% formaline for 7 days. After fixation, the liver was sectioned on 1-2mm thickeness. The slices were radiographed on high resolution plate using Faxitron. H-E staining of liver tissue was also done. RESULTS: The microbrium was well distributed in all small vessels without filling defect. And we could find the hexagonal shaped classic liver Iobule, in which the central vein was located at central portion and portal vein at periphery. The enlargement was showed numerous sinusoids, but there was less dye in the central portion of Iobule, but the central vein was well filled by microbarium. The peripheral portion of Iobule was well filled with microbarium. So, we could find diamond shaped liver acinus, in which central vein was located at priperal portion and the center of liver acinus was terminal portal vein that growed out from a small portal space. The three acini made the complex acinus and acinar agglomerate was composed of three or four complex acini. CONCLUSION: It is considered that the liver acinus pattern of Rapparport is more acceptable on microangiography than the classic concept of hepatic Iobule.

Dynamic Study of the Larynx with Spiral CT

PURPOSE: It is essential to know the functional and morphologic changes of the larynx in the evaluation of laryngeal lesions. Conventional CT which has relatively long examination time is not suitable for this aim. The purposes of this study are to evaluate the capability of spiral CT in the dynamic study of the larynx and to know whether this new technique can replace conventional laryngography or not. MATERIALS AND METHODS: Five healthy volunteers and 20 patients with laryngeal lesions underwent spiral dynamic CT scans with 3-dimensional reconstruction of the mucosal surface. A series of spiral CT scans were done while the volunteers performed various laryngeal positions to obtain the functional and morphologic information. The maneuvers used were:quite breathing, "E" phonation, Valsalva maneuver, modified Valsalva maneuver, and a new method of our own, "modified breath holding" technique. The patients were scanned when in quite breathing. Additioal scans were obtained by using the "modified breath holding" technique. RESULTS: The dynamic study with spiral CT could provide high resolutional images which nicely depicted the mobility of vocal cords and the mucosal changes of the laryngeal cavity in both healthy volunteer and patient groups. In patient group, the new "modified breath holding" technique was easier and more reproducible than other maneuvers. CONCLUSION: Spiral CT allows a dynamic study of the larynx and can be a new alternative of laryngography.

Dynamic Liver Scan with Sprial CT

PURPOSE: Dynamic liver scan with spiral CT during a single breath hold was performed for To determing the optimal timing of scanning and the degree of the enhancement of liver and vessel. MATERIALS AND METHODS: Liver spiral CT was performed on 143 patients and dynamic sequence scan on 2 normal volunteers. After baseline spiral CT without contrast enhancement, spiral CT was performed after administration of a bolus of 100 ml of nonionic contrast material intravenously with mechanical power injector at the constant injection rate of 2 ml/sec. Cephalocaudal scanning was started 45 seconds after the beginning of injection. In the majority of cases we employed 16-24 continuous scanning with table feed of 10 mm, slice thickness of 10 mm, and reconstructed in 5 or 10 mm section increments. We measured degree of enhancement of aorta, IVC, and liver parenchyma in all images. RESULTS: We have achieved bolus phase at all images from the following measured date; 170-250 H. U at aorta, 110-150 H. U at IVC, 80-125 H. U at liver parenchyma, 100-130 H. U at spleen, which shown contrast difference between aorta and IVC at least 45 H. U. At the dynamic sequence scan, aortic and vascular CT atternuation reaches a peak at 55-60sec and peak hepatic enhancement occurred at 70-75 sec with relative plateau achieve at 45 sec. Spiral CT also showed elimination of variation in diaphragmatic excursion. CONCLUSION: We could get the disirable phase imaging at overall examination from the dynamic liver scan around 45-60 seconds after injection of contrast media.