Bringing Physiology into PET of the Liver

Abstract

Several physiologic features make interpretation of PET studies of liver physiology an exciting challenge. As with other organs, hepatic tracer kinetics using PET is quantified by dynamic recording of the liver after the administration of a radioactive tracer, with measurements of time–activity curves in the blood supply. However, the liver receives blood from both the portal vein and the hepatic artery, with the peak of the portal vein time–activity curve being delayed and dispersed compared with that of the hepatic artery. The use of a flow-weighted dual-input time–activity curve is of importance for the estimation of hepatic blood perfusion through initial dynamic PET recording. The portal vein is inaccessible in humans, and methods of estimating the dual-input time–activity curve without portal vein measurements are being developed. Such methods are used to estimate regional hepatic blood perfusion, for example, by means of the initial part of a dynamic 18F-FDG PET/CT recording. Later, steady-state hepatic metabolism can be assessed using only the arterial input, provided that neither the tracer nor its metabolites are irreversibly trapped in the prehepatic splanchnic area within the acquisition period. This is used in studies of regulation of hepatic metabolism of, for example, 18F-FDG and 11C-palmitate.

Dynamic PET of human liver inflammation: impact of kinetic modeling with optimization-derived dual-blood input function

“…Conventionally it is either obtained by invasive arterial blood sampling or noninvasively derived from the left ventricle or aortic regions in dynamic PET images (39–41). In the liver, both the hepatic artery and portal vein provide blood supply to the hepatic tissue (22). The portal vein input is not the same as the hepatic artery input and is difficult to obtain in human subjects (22).…”

Respiratory gated PET/CT of the liver: A novel method and its impact on the detection of colorectal liver metastases

“…A potential decrease in FDG concentration in the hepatocytes compared to CRLM, due to high glucose-6-phosphatse activity, was therefore minimal and the effect on possibly increased sensitivity of rgPET/CT negligible [22,23]. Dirisamer et al found that a delayed PET-scan could improve sensitivity for liver metastases [24].…”

The Role of Organic Anion Transporters in Diagnosing Liver Diseases by Magnetic Resonance Imaging

“…Imaging techniques include PET, SPECT, and MRI. Because several recent reviews have documented the role of PET (Keiding, 2012;Kusuhara, 2013;Yoshida et al, 2013) and SPECT (de Graaf et al, 2010) in assessing the severity of human liver diseases, we focus on how MRI assesses focal lesions, diffuse liver diseases, and bile duct injury.…”

“…Thus, magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), and fluorescence imaging help clinicians to manage human liver diseases (Bae et al, 2012;Keiding, 2012;Stieger et al, 2012;Van Beers et al, 2012;Hoekstra et al, 2013;Kusuhara, 2013). Following a brief overview of the transport through OATPs and MRPs, this review highlights how MRI with hepatobiliary contrast agents is important to diagnose liver diseases.…”

“…Following a brief overview of the transport through OATPs and MRPs, this review highlights how MRI with hepatobiliary contrast agents is important to diagnose liver diseases. This review mainly focuses on magnetic resonance imaging (MRI) because several extended and well-documented reviews were recently published by experts for positron emission tomography (PET) (Keiding, 2012;Kusuhara, 2013;Yoshida et al, 2013) and single photon emission computed tomography (SPECT) (de Graaf et al, 2010;Hoekstra et al, 2013).…”