LETTER TO THE EDITORS Quantitative assessment of hepatic blood flow using intravenous indocyanine green

Letter to the editors Intravenous (IV) indocyanine green (ICG) is a tricarbocya-nine dye that is used to evaluate hepatic blood flow (QH) [1]. ICG has a high extraction ratio, is excreted unchanged in the bile, and does not undergo significant extrahepatic elimination or enterohepatic recirculation [2]. Consequent-ly, ICG clearance (CL) primarily depends on QH and can be a surrogate for quantifying QH [1, 3]. Several studies have reported that posture (e.g., supine, sitting, or standing) can produce significant changes in QH, as measured by ICG CL [3–5]. As part of a phenotyping study, we quantified posture-induced changes in QH using IV ICG. This study was approved by the Institutional Review Board of Bassett Healthcare, Cooperstown, NY, USA. Written informed consent was obtained from each subjec