Transportal Technetium-99m Labeled Macroaggregated Albumin Scintigraphy to Quantify Occult Intrahepatic Microvascular Portosystemic Shunting

Abstract

Nodular regenerative hyperplasia (NRH) of the liver may lead to noncirrhotic portal hypertension with subsequent development of portosystemic shunts. While extrahepatic and macrovascular shunts are readily visualized with imaging or endoscopy, there is no standard technique to detect intrahepatic microvascular portosystemic shunting and quantitatively assess shunt burden. We present a case of a 53-year-old female with suspected NRH and hepatopulmonary syndrome with inconclusive liver biopsies and absent portosystemic shunts per abdominal imaging. A percutaneous transportal infusion of Technetium-99m labeled macroaggregated albumin (99mTc-MAA) successfully identified intrahepatic microvascular portosystemic shunting and quantified a lung shunt fraction of more than 30%. NRH was subsequently confirmed with a surgical wedge biopsy and the patient was successfuly treated with a liver transplant. Transportal 99mTc-MAA could be used to both identify and quantify otherwise occult microvascular portosystemic shunts in patients with clinical sequelae of portal hypertension.

68Ga-Labeled Maleimide for Blood Pool and Lymph PET Imaging through Covalent Bonding to Serum Albumin In Vivo

“…A variety of blood pool imaging agents labeled with radionuclides have been developed, most of which are based on red blood cells (RBCs) − or plasma albumin. , Currently, 99m Tc-labeled RBCs and human serum albumin ([ 99m Tc]­Tc-RBCs and [ 99m Tc]­Tc-HSA) are still used as two major agents for clinical blood pool imaging. Thinking of the low in vivo labeling efficiency, RBCs need to draw blood for in vitro labeling, which is a time-consuming process with the risk of potentially infectious substances .…”