Relationship between the imaging features and pathologic alteration in hepatoma of rats

Multifunctional doxorubicin loaded superparamagnetic iron oxide nanoparticles for chemotherapy and magnetic resonance imaging in liver cancer

To develop a drug delivery system with enhanced efficacy and minimized adverse effects, we synthesized a novel polymeric nanoparticles, (YCC-DOX) composed of poly (ethylene oxide)-trimellitic anhydride chloride-folate (PEO-TMA-FA), doxorubicin (DOX) and superparamagnetic iron oxide (Fe(3)O(4)) and folate. The efficacy of the nanoparticles was evaluated in rats and rabbits with liver cancer, in comparison with free-DOX (FD) and a commercial liposome drug, DOXIL. YCC-DOX showed the anticancer efficacy and specifically targeted folate receptor (FR)-expressing tumors, thereby increasing the bioavailability and efficacy of DOX. The relative tumor volume of the YCC-DOX group was decreased two- and four-fold compared with the FD and DOXIL groups in the rat and rabbit models, respectively. Furthermore, YCC-DOX showed higher MRI sensitivity comparable to a conventional MRI contrast agent (Resovist), even in its lower iron content. In the immunohistochemical analysis, YCC-DOX group showed the lower expression of CD34 and Ki-67, markers of angiogenesis and cell proliferation, respectively, while apoptotic cells were significantly rich in the YCC-DOX group in terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. These results indicate that YCC-DOX is a promising candidate for treating liver cancer and monitoring the progress of the cancer using MRI.

Technology of in vivo two-dimension multi-voxel 1H magnetic resonance spectroscopy for rabbit liver VX2 tumor

AIM: To investigate the best techniques of in vivo two-dimension multi-voxel ¹H magnetic resonance spectroscopy (2D ¹H-MRS) for rabbit liver VX2 tumor.

METHODS: The liver of 8 New Zealand white rabbits was implanted directly and respectively with VX2 tumor lump after abdominal cavity was opened. 2D ¹H-MRS acquisition in vivo and unenhanced MRI was performed respectively from the 2^nd week to 4^th week after VX2 tumor was implanted. With knee coil, in vivo 2D ¹H-MRS acquisitions were performed respectively with different TR, different TE and different NEX at 1.5 T MR scanner when other parameters were the same. The distinction between groups was analyzed by SPSS11.0 with baseline and signal-noise ratio (SNR).

RESULTS: From the qualified MRS spectrum, there were up to 6 peaks which could be identified: methyl lipids (Lip1), methylene lipids (Lip2), methylene lipids with double carbon bond (Lip3), glutamine and glutamate complex (Glx), Choline (Cho), and glycogen and glucose complex (Glyu). Baseline and SNR had no significant differences between TR = 1000 ms, 2000 ms and 3000 ms. Baseline had no significant difference between TE = 30 ms and 144 ms. Except that SNR of Glx with 30 ms in TE was higher than that with 144 ms in TE (1.95 ± 0.36 vs 1.24 ± 0.26, P < 0.05), SNR of other metabolites were similar. With NEX increasing, the distinctions of baseline between NEX = 4, 8 and 16 were significant (χ² = 10.000, P < 0.01). SNR of all metabolites increased when NEX was increased gradually. Both of baseline and SNR were the best when NEX was 16.

CONCLUSION: It's practical of in vivo two-dimension multi-voxel ¹H-MRS on the rabbit liver VX2 tumor by a 1.5 T MR scanner. Immobilization, pre-scan (reaching FWHM ≤ 10 Hz and WS ≥ 98%), knee coil, TR = 1000 ms, TE = 30 ms and NEX = 16 may be the best to acquire highly qualified spectra.

Liver tumor model with implanted rhabdomyosarcoma in rats: MR imaging, microangiography, and histopathologic analysis

In compliance with institutional regulations for care and use of laboratory animals, the aim of this study was to establish and characterize a rodent liver tumor model to provide a platform for preclinical assessment of new diagnostic and therapeutic strategies. A rhabdomyosarcoma tumor was implanted in the right and left liver lobes of 20 rats, for a total of 40 tumors. T1- and T2-weighted magnetic resonance (MR) images, diffusion-weighted images, and dynamic susceptibility contrast agent-enhanced perfusion-weighted images were obtained up to 16 days after tumor implantation and were compared with postmortem three-dimensional computed tomographic (CT) images, digital microangiograms, and histopathologic findings. Fifteen tumors were examined with proton ((1)H) MR spectroscopy. All tumors grew, with a mean volume doubling time of 2.2 days +/- 0.9 (standard deviation) and a final size of 591 mm(3)+/- 124. The rhabdomyosarcoma tumor showed hypervascularity at MR imaging, three-dimensional CT, microangiography, and histologic analysis. On dynamic susceptibility contrast-enhanced perfusion-weighted images, the maximum signal intensity decrease differed in time and extent between the tumor and the liver, with a significantly (P < .001) higher relative blood volume, relative blood flow, and permeability value in the tumor than in the liver. With (1)H MR spectroscopy, the rhabdomyosarcoma tumor and the liver featured significant (P < .001) choline and lipid peaks, respectively. Implantation of a rhabdomyosarcoma tumor in the livers of rats is feasible and reproducible, and this animal model seems promising for future testing of new diagnostic and therapeutic strategies.