Determination of liver volume in vivo in rats using MRI

Accurate estimation of the liver volume may be important for the diagnosis of several pathological processes in patients and for the study of new therapies in experimental oncology. Although sonography and computed tomography (CT) have been used for this purpose in patients, the lack of spatial resolution and tissue differentiation is a source of measurement errors which, at present, makes it impossible to accept sonography and CT widely for the determination of the liver volume. In the present study, the liver volumes of seven rats were measured by magnetic resonance imaging (MRI) and an automated image analysis system before and after the animals were killed. Volume computation was carried out by adding up the individual volumes in the sequential MR sections. Adequate MR images with high contrast between the liver and surrounding structures were obtained with spin echo pulse sequence and retarded phase encoding while no contrast material was used. The mean volumes of the livers measured by MR in vivo and in cadavers were 11.91 ± 0.40 and 11.92 ± 0.45 ml, respectively. When compared with the actual liver volumes measured in vitro after resection, the errors of determinations in vivo and in cadavers were as small as 3.1 and 2.1%, respectively. These data indicate that MR imaging is an accurate means to determine the liver volume in vivo and that it may be potentially useful to measure small intrahepatic lesions in patients. © 1990.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Quantitative study of the growth of experimental hepatic tumors in rats by using magnetic resonance imaging

Precise estimation of the volume and growth rate of hepatic metastases would represent an important step forward not only in clinical oncology but also for the evaluation of experimental treatments in animal models. In the present study, an original method of volumetry of hepatic metastatic tumors in vivo has been tested in rats using magnetic resonance imaging (MRI). Three different hepatic tumor models mimicking liver metastases were established in syngeneic BDIX rats by injection of DHD/K12 rat colon cancer cells either directly under the liver capsule or via the portal system. The liver tumor volumes were estimated in vivo by using MR imaging of the liver and summing the individual tumor volumes in the sequential MR liver sections. The values of the tumor volumes measured by MRI were compared with those determined by a classical method of water displacement in vitro after killing the animals and excising the tumors. At 3 weeks after tumor implantation, liver tumors as small as 1 mm in diameter could be detected by MRI. The difference between the tumor volumes estimated by MRI in vivo and those measured by water displacement in vitro was 9% for single liver tumors and 16% for multiple liver tumors. Close correlation between the values of the tumor volumes measured by MRI and those determined by water displacement was observed in solitary liver tumors (r = 0.985, p < 0.01) as well as in multiple liver tumors (r = 0.985, p < 0.01), indicating the high accurary of MRI volumetry for liver tumors. Estimation of the liver tumor volumes by MRI in the same animals at successive time intervals made it possible to construct tumor growth curves and to calculate tumor growth parameters. These data suggest that MRI volumetry represents an effective means of evaluating the efficacy of experimental treatments in small animals and may have potentially important applications in clinical patients.SCOPUS: ar.jFLWNAinfo:eu-repo/semantics/publishe

Inhibitory effect of somatostatin analogue RC-160 on the growth of hepatic metastases of colon cancer in rats: A study with magnetic resonance imaging

The effect of somatostatin analogue RC-160 on the growth of hepatic metastases of colon cancer was investigated in rats using magnetic resonance imaging. Experimental liver metastatic tumors were established in syngeneic BDIX rats after intrasplenic injection of DHD/K12 colon adenocarcinoma cells. Each rat with implanted liver tumors received s.c. injections of somatostatin analogue RC-160 (50 μg/kg) or the vehicle (control) twice a day for 4 weeks, starting 3 weeks after tumor inoculation. During the treatment with RC-160, the growth of liver tumors was studied quantitatively by measuring liver tumor volumes in vivo with magnetic resonance imaging at intervals of 7 days. Chronic administration of RC-160 inhibited the growth of hepatic metastases of colon cancer in rats. Significant inhibition of liver tumor growth in RC-160-treated rats was observed throughout the treatment. The final liver tumor volume in the treated rats was decreased by 56.1% as compared to the controls. The treatment with RC-160 reduced the percentage increase in liver tumor volume from 1575 ± 674% (mean ± SEM) for the control to 1034 ± 727% in the treated group. The tumor volume doubling time in treated rats was 3.7 days longer than the controls. The liver tumor growth delay time was 15.1 days. At the end of the treatment, the incidence of ascites and the weights of tumorous livers were also decreased by RC-160 treatment. Administration of RC-160 prolonged the median survival time by 13 days in treated rats. In cell cultures, significant inhibitory effects of somatostatin-14 and RC-160 on the growth of DHD/K12 colon cancer cells were determined by MTT assay and [3H]-thymidine incorporation assay, indicating direct effects of these peptides on the growth of colon cancer cells in vitro. These data suggest that administration of RC-160 could inhibit the growth of colon cancer and their hepatic metastases in rats. Somatostatin analogue RC-160 might be considered as a potential new agent for the treatment of patients with hepatic metastases of colorectal cancers.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Inhibitory effect of somatostatin analogue RC-160 on the growth of hepatic metastases of colon cancer in rats: a study with magnetic resonance imaging.

The effect of somatostatin analogue RC-160 on the growth of hepatic metastases of colon cancer was investigated in rats using magnetic resonance imaging. Experimental liver metastatic tumors were established in syngeneic BDIX rats after intrasplenic injection of DHD/K12 colon adenocarcinoma cells. Each rat with implanted liver tumors received s.c. injections of somatostatin analogue RC-160 (50 µg/kg) or the vehicle (control) twice a day for 4 weeks, starting 3 weeks after tumor inoculation. During the treatment with RC-160, the growth of liver tumors was studied quantitatively by measuring liver tumor volumes in vivo with magnetic resonance imaging at intervals of 7 days. Chronic administration of RC-160 inhibited the growth of hepatic metastases of colon cancer in rats. Significant inhibition of liver tumor growth in RC-160-treated rats was observed throughout the treatment. The final liver tumor volume in the treated rats was decreased by 56.1% as compared to the controls. The treatment with RC-160 reduced the percentage increase in liver tumor volume from 1575 ± 674% (mean ± SEM) for the control to 1034 ± 727% in the treated group. The tumor volume doubling time in treated rats was 3.7 days longer than the controls. The liver tumor growth delay time was 15.1 days. At the end of the treatment, the incidence of ascites and the weights of tumorous livers were also decreased by RC-160 treatment. Administration of RC-160 prolonged the median survival time by 13 days in treated rats. In cell cultures, significant inhibitory effects of somatostatin-14 and RC-160 on the growth of DHD/K12 colon cancer cells were determined by MTT assay and [3H]-thymidine incorporation assay, indicating direct effects of these peptides on the growth of colon cancer cells in vitro . These data suggest that administration of RC-160 could inhibit the growth of colon cancer and their hepatic metastases in rats. Somatostatin analogue RC-160 might be considered as a potential new agent for the treatment of patients with hepatic metastases of colorectal cancers

Non‐Invasive in Vivo Determination of the Absolute ATP Concentration in the Rat Liver by 31P NMR Spectroscopy

The concentration of ATP in the rat liver was determined in vivo by means of surface coil 31P NMR spectroscopy. The double standard method was used in order to achieve absolute quantification of ATP through its 31P β‐resonance. Contamination of the 31P NMR liver spectra by contributions from abdominal muscle tissue was minimized by applying the FROGS presaturation sequence. Difficulties inherent to the B1 inhomogeneity of surface coils were overcome by the use of adiabatic half passage sech/tanh RF pulses. While in the normal rat liver the mean ATP concentration was 3.39 ± 0.31 mM, fibrotic rat livers exhibited a significantly lower average ATP concentration of 2.29 ± 0.31 mM. Copyright © 1992 Wiley‐VCH Verlag GmbH & Co. KGaA, WeinheimSCOPUS: ar.jinfo:eu-repo/semantics/publishe