Effects of Liver Fibrosis Progression on Tissue Relaxation Times in Different Mouse Models Assessed by Ultrahigh Field Magnetic Resonance Imaging.

Recently, clinical studies demonstrated that magnetic resonance relaxometry with determination of relaxation times T1 and T2⁎ may aid in staging and management of liver fibrosis in patients suffering from viral hepatitis and steatohepatitis. In the present study we investigated T1 and T2⁎ in different models of liver fibrosis to compare alternate pathophysiologies in their effects on relaxation times and to further develop noninvasive quantification methods of liver fibrosis. MRI was performed with a fast spin echo sequence for measurement of T1 and a multigradient echo sequence for determination of T2⁎. Toxic liver fibrosis was induced by injections of carbon tetrachloride (1.4 mL CCl4 per kg bodyweight and week, for 3 or 6 weeks) in BALB/cJ mice. Chronic sclerosing cholangitis was mimicked using the ATP-binding cassette transporter B4 knockout (Abcb4 -/-) mouse model. Untreated BALB/cJ mice served as controls. To assess hepatic fibrosis, we ascertained collagen contents and fibrosis scores after Sirius red staining. T1 and T2⁎ correlate differently to disease severity and etiology of liver fibrosis. T2⁎ shows significant decrease correlating with fibrosis in CCl4 treated animals, while demonstrating significant increase with disease severity in Abcb4 -/- mice. Measurements of T1 and T2⁎ may therefore facilitate discrimination between different stages and causes of liver fibrosis.

[11C]choline uptake in regenerating liver after partial hepatectomy or CCl4-administration.

To characterize [methyl-(11)C]choline ([(11)C]choline) as an oncologic PET radiopharmaceutical, [(11)C]choline uptake in regenerating livers after partial hepatectomy as a model of typical proliferating tissue and after CCl(4) insult as that of proliferating tissue with inflammation, was studied in rats. [(11)C]Choline, [(18)F]2-fluoro-2-deoxy-D-glucose ([(18)F]FDG) and [2-(14)C]thymidine ([(14)C]TdR) uptake was studied in regenerating rat liver after 70% partial hepatectomy or CCl(4)-administration. [(11)C]Choline uptake in regenerating liver after partial hepatectomy was significantly increased with [(14)C]TdR uptake as a marker of DNA synthesis at 18 hours after surgery. On the other hand, the uptake was not accelerated by CCl(4)-administration, though it significantly increased [(14)C]TdR uptake. There were no differences of [(11)C]choline uptake acceleration following partial hepatectomy among the three parts of the regenerating liver. [(18)F]FDG uptake was accelerated in the regenerating liver on either partial hepatectomy or CCl(4)-administration. The magnitude of the increase in [(18)F]FDG uptake in the regenerating liver induced by partial hepatectomy was greater than that for [(11)C]choline. [(11)C]Choline uptake in the liver was accelerated by partial hepatectomy, but not by CCl(4)-administration. This might be expected given that the differentiation between proliferating tissues such as tumor and inflammatory tissue was possible by [(11)C]choline-PET.

8-cyclopentadienyltricarbonyl 99mtc 8-oxooctanoic acid: a novel radiotracer for evaluation of medium chain fatty acid metabolism in the liver.

8-Cyclopentadienyltricarbonyl 99mTc 8-oxooctanoic acid (99mTc-CpTTOA; 1a) was synthesized for evaluation of medium chain fatty acid metabolism in the liver. 99mTc-CpTTOA was prepared in high radiochemical yield (50-63%) by a double ligand transfer reaction of methyl 8-ferrocenyl-8-oxooctanoate and Na99mTcO4 in the presence of CrCl3 and Cr(CO)6, followed by hydrolysis. This radiotracer was shown to be stable (>90% at 6 h) when incubated with human serum. Aqueous extraction of the radioactivity from the liver and blood samples of mice suggested that 99mTc-CpTTOA was mainly metabolized via beta-oxidation in the liver, and the radioactivity was retained longer in CCl4-treated mice than in control mice, possibly due to impaired beta-oxidation in the former. Planar images of rats injected with 99mTc-CpTTOA showed accumulation of the radioactivity in the liver, kidneys, and bladder with rapid hepatic clearance as a function of time. Analysis of the metabolites from the liver and urine samples of rats further supported that 99mTc-CpTTOA was metabolized to 4-cyclopentadienyltricarbonyl 99mTc 4-oxobutanoic acid (99mTc-CpTTBA; 1c) via beta-oxidation. The results suggested that this radiotracer might be of valuable use in the evaluation of fatty acid metabolism in the liver.

[Evaluation of liver function in carbon tetrachloride-damaged rabbits by dynamic SPECT: comparison of 99mTc-GSA and 99mTc-Sn colloid].

Technetium-99m-DTPA-galactosyl human serum albumin (99mTc-GSA) is a new ligand that binds specifically to asialoglycoprotein receptors in hepatocytes. We performed liver dynamic SPECT using 99mTc-GSA and 99mTc-Sn colloid in nine normal control rabbits and 17 chronically CCI4-damaged rabbits (total 29 examinations), and also performed liver function tests (ICGR15, Alb, etc). Using the obtained dynamic SPECT data, we analyzed the liver kinetics of 99mTc-Sn colloid using a one-compartment model (hepatic blood flow [K]) and 99mTc-GSA using a two-compartment model (hepatic blood flow and receptor binding [K1], catabolism [K2]). As the CCl4-treated period increased, K1 decreased most significantly. K1 showed the most significant statistical correlation with the results of liver function tests, ICGR15 (p < 0.0001), Alb, PT, HP, Bil and GPT. Further, only K1 showed a correlation with the hepatic fibrosis of the HAI score. From the present results, liver dynamic SPECT using 99mTc-GSA may be said to provide a novel method for the evaluation of hepatic functional reserve.

Computerized ultrasound B-scan texture analysis of experimental diffuse parenchymal liver disease: correlation with histopathology and tissue composition.

By means of statistical pattern recognition procedures, a quantitative description of the ultrasound B-scan images of experimental diffuse liver disease has been carried out. Fatty livers, fatty fibrosis/cirrhosis, and cirrhosis without fatty infiltration of the liver were studied in female Wistar rats. Separation accuracies of more than 80% between the tissue classes "normal" vs "fatty infiltration," or "normal" vs "fatty cirrhosis," using only two statistical image parameters were found. A subclassification of the diffuse parenchymal liver disease was not possible. It is shown by multiple linear regression analysis that the image parameter "mean grey level" correlates better with total lipid content than with the amount of connective tissue. Furthermore it is demonstrated that connective tissue leads only to a weak increase in "mean grey level," whereas the addition of connective tissue to a given tissue lipid can lead to a reduction in image brightness.

Assessment of Kupffer cell function in rats with chronic liver injury caused by CCl4.

Kupffer cell function was assessed by using scintigraphy to evaluate the turnover of a metabolizable tracer (99mTc-millimicrosphered albumin). The organ uptake rate of the tracer, and new parameters concerned with the degradative functions of Kupffer cells obtained from analysis of the excretion phase of the hepatic time-uptake rate curve, were measured in rats with two different types of chronic liver damage induced by carbon tetrachloride (fatty liver group and liver cirrhosis group). The hepatic uptake rate in chronic liver injury decreased, while in contrast the splenic and pulmonary uptake rates increased. A particularly high uptake by the lungs was observed. The data demonstrated a reduced phagocytic activity of the Kupffer cells in rats with chronic liver injury. The new parameters concerned with Kupffer cell degradative function; i.e. the excretion rate (K) and the degradation rate in the first 60-min (D60), were markedly decreased even in the early stage of chronic liver injury. The data showed that the impairment of Kupffer cell degradative function occurred even earlier in liver damage than impairment of the phagocytic activity, so that the K value and the D60 value were the more sensitive indicators of Kupffer cell function.

Relation between blood clearance and hepatic uptake of 99mTc-phytate in rats with hepatic injury.

The relation among the blood clearance of 99mTc-phytate (99mTc-P), the hepatic uptake of 99mTc-P and the severity of hepatic injury was investigated by using the rats with carbon tetrachloride (CCl4), D-galactosamine (Gal N), alpha-naphthylisothiocyanate (ANIT) or DL-ethionine (EthN) induced hepatic injury. After the administration of CCl4, GalN or ANIT, serum GPT activity increased significantly with the increase of dose level, and the degree of this increase was in the order: GalN greater than CCl4 greater than ANIT. However, the mild increase in serum GPT activity was observed after EthN administration. The blood clearance rate of 99mTc-P and the hepatic uptake ratio of 99mTc-P decreased with the increase of dose level after CCl4, GalN or ANIT administration, but significant changes were not found after EthN administration. The degree of decrease in the blood clearance rate of 99mTc-P was in the order: GalN not equal to CCl4 greater than ANIT, and the degree of decrease in the hepatic uptake ratio of 99mTc-P was in the order: GalN not equal to CCl4 greater than ANIT. These results suggest that the disorder in the hepatocytes may be one of causes for inducing the decrease in the hepatic uptake of 99mTc-P, and the consequence of this decrease may induce the decrease in the blood clearance of 99mTc-P.

Experimental study of iron effect on the liver function.

The effect of iron on the liver function was studied in rats. A total of 40 rats were divided into four groups. Group 1 was given iron; Group 2, carbon tetrachloride; Group 3, a combination of iron and carbon tetrachloride; and Group 4 was the control. The changes in liver function were evaluated by using hepatobiliary and liver scintigraphy as the index of hepatocyte function and reticuloendothelial system function, respectively. Determination of liver CT number and a histological study were made at the same time. The administration of iron activated the reticuloendothelial system function per unit of liver weight. However, because of the decrease in liver weight, the total reticuloendothelial system function did not change at all. In the group given iron and carbon tetrachloride, liver cirrhosis and siderosis in the reticuloendothelial system occurred. Dysfunction in the reticuloendothelial system was more severe in this group than in the group given carbon tetrachloride only, by hepatocyte dysfunction was more mild. It is doubtful that the administration of iron after liver dysfunction had developed, which caused acceleration of fibrosis and reduction of liver blood flow, led to the enhancement of the reticuloendothelial system dysfunction.

Survival after massive ingestion of carbon tetrachloride treated by intravenous infusion of acetylcysteine.

A 61-year-old man ingested a large amount of carbon tetrachloride, well in excess of the adult lethal dose. The level of the compound was assayed in his blood and the levels were the highest ever recorded by the Guy's Hospital Poisons Unit. He was treated by intravenous infusion of acetylcysteine and survived with relatively mild clinical and biochemical evidence of toxicity. Possible reasons for his survival are discussed, as are the implications for the management of future cases.

[Roentgenocontrast lienography in experimental diffuse liver lesions]. / Rentgenokontrastnaia lienografiia pri éksperimental'nom diffuznom porazhenii pecheni.

The diagnostic potentialities of i. v. lienography were studied in experiments on rodents during the administration of the liposome forms of radiographic contrast agents (RCA) in the presence of chronic diffuse liver lesion simulated by subcutaneous injection of 50% oil solution of CCl4 for 2 months. The time-course of splenomegaly was found to be in direct relation to the CCl4 summary dose. The degree of pathomorphological changes of the hepatic tissue and pathological shifts in the blood clinical and biochemical findings show good correlation with the time-course of splenomegaly. The use of the RCA liposome forms extends the range of radiodiagnostic potentialities in the recognition of chronic diffuse liver lesion.

Evaluation of portal circulation in rats by rectal administration of 201Tl followed by intrasplenic injection of 51Cr-labeled microspheres.

The heart-to-liver (H/L) uptake ratio in rats was determined 8 min after the rectal administration of 201Tl. Apart from normal controls, three groups of rats were examined; these were composed of animals with induced (1) acute hepatic damage, (2) liver cirrhosis, and (3) partial portal-vein ligation. After the rectal administration of 201Tl, 51Cr-labeled microspheres were injected into the spleen. The radioactivity of the removed liver, lungs, and heart was determined in a gamma-well scintillation counter, and the radioactivity of 201Tl and the 51Cr-labeled microspheres was separately calculated using simultaneous equations derived from the results of a preliminary experiment. The H/L ratios (201Tl) in the normal controls and the animals with acute hepatic damage were not significantly different; however, there was a positive correlation (P less than 0.01) between the H/L ratio and the shunt index (51Cr microspheres) in three groups, i.e., normal controls, liver cirrhosis, and partial portal-vein ligation.

Radiographic demonstration of a toxic agent.

The abdominal radiographs obtained on a young man attempting suicide by stabbing revealed an unusual opacity in the true pelvis, confirmed as being due to unsuspected carbon tetrachloride ingestion. This is the first known radiologic demonstration of oral ingestion of a rapidly acting toxic substance.

The relation of liver fat to computed tomography numbers: a preliminary experimental study in rabbits.

The relation of liver fat content to CT number was studied in 20 rabbits (17 experimental, 3 control), where fatty degeneration was produced by carbon tetrachloride (CCl4) ingestion. Liver scanning was performed before and 2--5 days after CCl4 administration.. Changes (decrease) in CT number were compared with triglyceride (TG), water, and protein content of resected livers. A decrease of 12--20 CT numbers (24--40 H) reflected a TG concentration of 20--40 mg/g.