[Experimental study of per-rectal portal scintigraphy using 99mTc-EHIDA].

We discovered that 99mTc-EHIDA commonly used for hepatobiliary scintigraphy could also be administered per-rectally, with adequate absorption and optimal visualization of the portal system. To evaluation its usefulness, we experimented on rabbits using the method. Portal scintigraphy with rectal administration of 99mTc-EHIDA, 123I-IMP and 99mTc-RBC were performed in normal rabbits and in extrahepatic portal shunt model rabbits. Images of the liver and thorax were obtained and shunt indices were calculated from the count values of liver and lung or heart. Then the shunt indices were compared with shunt rate derived from direct injection of 99mTc-MAA into inferior mesenteric vein. Correlation between shunt rate of 99mTc-MAA and shunt indices of 99mTc-RBC, 123I-IMP and 99mTc-EHIDA were 0.64, 0.75 and 0.78, respectively, with 99mTc-EHIDA having the most favourable results. We concluded that 99mTc-EHIDA per-rectal portal scintigraphy is a noninvasive, quantitative, inexpensive and simple method for evaluation of portal circulation system. Also, we think that this method would be applicable to human usage from our experience with normal volunteers.