^99mTc-GSA Scintigraphy with SPECT for Assessment of Hepatic Function and Functional Volume During Liver Regeneration in a Rat Model of Partial Hepatectomy

Abstract

Small-animal models are crucial to gain insights in the complex recovery mechanisms of liver function during liver regeneration. 99m Tc-Mebrofenin hepatobiliary scintigraphy (HBS) has been introduced for noninvasive assessment of liver function in the clinical setting as well as in experimental research. However, HBS is restricted to planar modalities in small animals because hepatic kinetics are generally too fast for SPECT acquisition. 99m Tc-DTPA-galactosyl serum albumin (where DTPA is diethylenetriaminepentaacetic acid) ( 99m Tc-GSA) scintigraphy is an alternative, receptor-mediated, noninvasive liver function test. After hepatic uptake, 99m Tc-GSA remains trapped in the liver, which readily enables additional SPECT for the assessment of both liver function and liver functional volume within one test. In this study we evaluated the use of 99m Tc-GSA scintigraphy combined with SPECT for the assessment of liver function and liver functional volume in normal and regenerating rat livers. Methods: The reproducibility of 99m Tc-GSA scintigraphy and SPECT was investigated by repeated measurements within the same rat. For the assessment in a regenerating liver, 99m Tc-GSA scintigraphy with SPECT was performed on 1, 3, 5, and 7 d (n 5 6 rats per time point) after 70% partial hepatectomy (PH). Results: The correlation between repeated 99m Tc-GSA measurements was strong (r 5 0.75, P 5 0.019). In normal rat livers, there was a strong, significant correlation between liver functional volume and conventional liver volume (r 5 0.93; , 0.0001). The correlation between 99m Tc-GSA uptake and liver volume was moderate (r 5 0.62, P 5 0.043). During the regeneration process, 99m Tc-GSA uptake was significantly lower compared with both liver volume (P , 0.001) and liver functional volume (P , 0.001), when expressed as a percentage of baseline levels. There was a strong correlation between liver functional volume and conventional liver volume in the regenerating liver (r 5 0.92, P , 0.0001). Conclusion: 99m Tc-GSA scintigraphy combined with SPECT is a feasible, noninvasive method to assess hepatic functional volume in normal rat liver as well as in the regenerating rat liver. However, the hepatic 99m Tc-GSA uptake as a liver function test seems to underestimate hepatic regeneration in comparison to liver volume. Part ial liver resection is the most effective treatment for primary and secondary liver malignancies (1). To ensure safe postoperative recovery, sufficient remnant liver volume and function are crucial as posthepatectomy liver failure still has high mortality. When sufficient remnant liver is present, the liver has the unique ability to regenerate to its original size. Several conditions are known to influence liver regeneration, including the extent of resection, the presence of underlying parenchymal liver disease (2), diabetes, and the age of the patient (3). Impaired liver regeneration can cause serious clinical problems, such as delayed recovery of postoperative liver function and increased risk of postoperative live...

Quantitative Assessment of Hepatic Function During Liver Regeneration in a Standardized Rat Model

“…Nuclear scans were obtained after an overnight fast as described before (1). A bolus of 40 MBq of 99m Tc-mebrofenin (Bridatec; GE Healthcare) or 40 MBq of 99m Tc-GSA (Nihon Mediphysics) in 0.3 mL of saline was administered through the tail vein.…”

“…99m Tc-GSA SPECT was used to calculate FLV as reported previously (1). After dynamic 99m Tc-GSA scintigraphy, SPECT images were acquired at 30 min after intravenous injection of 99m Tc-GSA.…”

“…Several conditions can influence liver regeneration, including the extent of resection, diabetes, and the presence of underlying liver disease (1). In the case of liver transplantation, the length of the cold ischemic period and the presence of organ rejection are of additional importance.…”

Index of convexity: A novel method for assessing liver functional reserve using technetium-99m-galactosyl human serum albumin liver scintigraphy

“…Technetium-99m diethylenetriamine-penta-acetic acid-galactosyl human serum albumin ( 99m Tc-GSA) scintigraphy is one of the prevalent examinations performed for evaluation of liver functional reserve (17)(18)(19)(20)(21)(22)(23)(24)(25). Conventional indices of 99m Tc-GSA scintigraphy, namely the blood clearance index (HH15) and the receptor index (LHL15), use accumulation counts of only two time points.…”

Comparison Between the Values of the Hepatic Uptake Rate Obtained by 2 Methods, Using Hepatobiliary Scintigraphy in Patients with Nonalcoholic Steatohepatitis

“…Morphologic imaging (CT and ultrasound) rely on volume changes of the liver, which do not always represent hepatic function, indicating the importance of additional functional assessment of the liver (8)(9)(10).…”