Ans. is 'c' i.e., Focal nodular hyperplasia Liver parenchyma is primarily made up of two types of cells. i) Hepatocytes -> Perform excretory and synthetic function ii) Kupffer cells -> They have reticuloendothelial function Both these cells can be investigated with 99mTc labelled cells. Two types of radionucleide imaging procedure are used in liver Hepatocyte based imaging (IDA Imaging) - IDA compound are taken up by functioning hepatocytes, excreted unchanged in the bile and are not reabsorbed from the gut This propey of IDA compounds is used in imaging of liver and biliary tract. It will allow the imaging of functioning liver parenchyma and trace the flow of the bile, in the ducts, gall bladder and bowel - Its clinicals use are i) Assessment of regional liver function ii) Demonstration of bile leaks in liver trauma iii) Investigation of biliary obstruction iv) Choledochal cyst v) Demonstration of gall bladder function including cystic duct obstruction as a marker of acute cholecystitis. - Remember the question asked about the use of HIDA scan in acute cholecystitis. If the gall bladder is not demonstrated by 4 hrs it is a good indicator of acute cholecystitis due to mechanical or functional obstruction of cystic duct. vi) Differentiation of hepatocellular tumours.