Assessment of liver function in chronic liver diseases and regional function of irradiated liver by means of 99mTc-galactosyl-human serum albumin liver scintigraphy and quantitative spectral analysis

A radiologist's point of view in the presurgical and intraoperative setting of colorectal liver metastases

Multidisciplinary management of patients with metastatic colorectal cancer requires in each phase an adequate choice of the most appropriate imaging modality. The first challenging step is liver lesions detection and characterization, using several imaging modality ultrasound, computed tomography, magnetic resonance and positron emission tomography. The criteria to establish the metastases resectability have been modified. Not only the lesions number and site but also the functional volume remnant after surgery and the quality of the nontumoral liver must be taken into account. Radiologists should identify the liver functional volume remnant and during liver surgical procedures should collaborate with the surgeon to identify all lesions, including those that disappeared after the therapy, using intraoperative ultrasound with or without contrast medium.

Sequential evaluation of hepatic functional reserve by 99mTechnetium-galactosyl human serum albumin scintigraphy after proton beam therapy: a report of three cases and a review of the literatures

The treatment strategy for malignant liver tumors should be appropriately determined because post-treatment quality of life greatly depends on the patients' residual hepatic function. In this report, we present three patients with malignant liver tumors treated by proton beam therapy in whom pre- and post-therapeutic hepatic functional reserves were evaluated sequentially for more than a year by 99mTechnetium-galactosyl human serum albumin (99mTc-GSA) scintigraphy. All three patients exhibited the distinctive time course of 99mTc-GSA uptake efficiency, which suggested a transient decline in the ratio of liver activity to heart and liver activity at 15 minutes (LHL15) 3-6 months after proton beam therapy. This change was not in parallel with that expected from a functioning normal liver tissue volume. In a year after proton beam therapy, LHL15 recovered nearly to the pre-treatment level in all three patients. Our observations may be related to the up-regulation of receptor-mediated 99mTc-GSA uptake during hepatic regeneration after proton beam therapy.

Spectral analysis: principle and clinical applications

This review article describes the principle and clinical applications of spectral analysis. Spectral analysis provides a spectrum of the kinetic components which are involved in the regional uptake and partitioning of tracer from the blood to the tissue. This technique allows the tissue impulse response function to be derived with minimal modeling assumptions. Spectral analysis makes no a priori assumptions regarding the number of compartments or components required to describe the time course of tracer in the tissue. Spectral analysis can be applied to various dynamic data acquired by planar scintigraphy, single photon emission computed tomography (SPECT) or positron emission tomography (PET) as an alternative approach to compartment analysis. This analysis appears to be clinically useful, because it not only facilitates the interpretation of dynamic scintigraphic, SPECT or PET data, but also simplifies comparisons between regions and between subjects.

Evaluation of the effect of age on functioning hepatocyte mass and liver blood flow using liver scintigraphy in preoperative estimations for surgical patients: comparison with CT volumetry

BACKGROUND

The effect of age on functioning hepatocyte mass and liver blood flow was examined using (99m)Tc-galactosyl-human serum albumin (GSA) liver scintigraphy in patients with liver tumors awaiting surgery.

MATERIALS AND METHODS

Seventy-two patients with liver tumors, but normal liver parenchyma, were included in this study; patients with compromised hepatic blood flow as a result of vascular invasion or thrombus were excluded. The liver volume, calculated liver volume, and liver blood flow index (K value) were preoperatively determined by liver scintigraphy using GSA. These three parameters and liver volume measured by computed tomography volumetry (CT-LV) and the standard liver volume (ST-LV), calculated from the patient's body surface area, were examined for correlations with the patient's age. The K value was compared with the indocyanine green dye retention rate, and both sets of results were examined for correlation with the patient's age.

RESULTS

Both the CT-LV and the ST-LV decreased with age, resulting in an unchanged CT-LV/ST-LV ratio with aging. The liver volume and calculated liver volume measured by scintigraphy both decreased with age, even when body size was taken into account. Therefore, in elderly patients, the liver was not morphologically smaller, but the hepatocyte mass in the liver decreased. Furthermore, liver blood flow per unit of functional liver volume determined from the blood flow index did not change with age.

CONCLUSIONS

These results, suggesting a discrepancy between liver volume estimated by CT and actual functioning hepatocyte volume in the elderly, may have a critical impact on preoperative liver functional reserve evaluation prior to hepatic resection in elderly patients.