Friday May 19, 2006
HIDA, DISIDA and BRIDA scan
Hepatic 2,6-dimethyliminodiacetic acid (HIDA) and Diisopropyl iminodiacetic acid (DISIDA) are nuclear studies to assess the function of the gallbladder and obstruction of the Common Bile Duct (CBD) in cholecystitis, cholangitis, billiary leak and atresia. These tests are ordered when ultrasound is equivocal. When you will order HIDA Scan or DISIDA scan ?
Nuclear Medicine literature is vast in this regard but to be short and simple, HIDA scan is used when serum bilirubin is less than 5-7 mg/dl and DISIDA scan is used when serum bilirubin is more than 7 mg/dl. DISIDA scan is now largely used instead of HIDA scan. The basis of this difference is relatively higher hepatic extraction. HIDA scan can be falsely positive when the gallbladder is not filling despite absence of cholecystitis like in severe liver disease (hyperbilirubinemia), patients on TPN or patient NPO for more than 24 hours, alcohol and opiate abuse. In case, serum bilirubin is extremely high (> 30 mg/dl), you can call for Mebrofenin (BRIDA) scan. Mebrofenin has even higher hepatic extraction than DISIDA scan.
Related Previous pearl: Acute acalculous cholecystitis in ICU