Dual-modality imaging with 99mTc and fluorescent indocyanine green using surface-modified silica nanoparticles for biopsy of the sentinel lymph node: an animal study

BACKGROUND: We propose a new approach to facilitate sentinel node biopsy examination by multimodality imaging in which radioactive and near-infrared (NIR) fluorescent nanoparticles depict deeply situated sentinel nodes and fluorescent nodes with anatomical resolution in the surgical field. For this purpose, we developed polyamidoamine (PAMAM)-coated silica nanoparticles loaded with technetium-99m ((99m)Tc) and indocyanine green (ICG). METHODS: We conducted animal studies to test the feasibility and utility of this dual-modality imaging probe. The mean diameter of the PAMAM-coated silica nanoparticles was 30 to 50 nm, as evaluated from the images of transmission electron microscopy and scanning electron microscopy. The combined labeling with (99m)Tc and ICG was verified by thin-layer chromatography before each experiment. A volume of 0.1 ml of the nanoparticle solution (7.4 MBq, except for one rat that was injected with 3.7 MBq, and 1 μg of an ICG derivative [ICG-sulfo-OSu]) was injected submucosally into the tongue of six male Wistar rats. RESULTS: Scintigraphic images showed increased accumulation of (99m)Tc in the neck of four of the six rats. Nineteen lymph nodes were identified in the dissected neck of the six rats, and a contact radiographic study showed three nodes with a marked increase in uptake and three nodes with a weak uptake. NIR fluorescence imaging provided real-time clear fluorescent images of the lymph nodes in the neck with anatomical resolution. Six lymph nodes showed weak (+) to strong (+++) fluorescence, whereas other lymph nodes showed no fluorescence. Nodes showing increased radioactivity coincided with the fluorescent nodes. The radioactivity of 15 excised lymph nodes from the four rats was assayed using a gamma well counter. Comparisons of the levels of radioactivity revealed a large difference between the high-fluorescence-intensity group (four lymph nodes; mean, 0.109% ± 0.067%) and the low- or no-fluorescence-intensity group (11 lymph nodes; mean, 0.001% ± 0.000%, p < 0.05). Transmission electron microscopy revealed that small black granules were localized to and dispersed within the cytoplasm of macrophages in the lymph nodes. CONCLUSION: Although further studies are needed to determine the appropriate dose of the dual-imaging nanoparticle probe for effective sensitivity and safety, the results of this animal study revealed a novel method for improved node detection by a dual-modality approach for sentinel lymph node biopsy

Small bowel transplantation in rats: Endoscopic and histological evaluation of graft rejection

Heterotopic small bowel transplantation was performed using the cuff technique in DA(RTl) to PVG(RT1) rat fully allogeneic combination. In this model, the rejection course of the grafted intestine was evaluated endoscopically via double stomata and was classified into four stages. Early changes appeared on postoperative day 3. Stage I: The mucosa of the grafted intestine showed patchy paleness and loss of the capillary fine network patterns, accompanied by microerosions. Closer examination revealed irregularity of the epithelial height and arrangement. Stage II: The damage spread progressively over the entire mucosa on day 4-5. Stage III: On day 6-7, the necrotic epithelium became detached, showing multiple ulcers which provoked hemorrhagic enteritis. Stage IV: Graft rejection was completed with total necrosis and white scar tissue formation by day 10-14. These endoscopic findings of the mucosa of the grafted intestine corresponded closely to the time course of pathological examinations. We conclude that endoscopic examination of grafted intestine may be an effective diagnostic tool to detect the rejection phenomenon at an early stage, as well as a simple tool to use for postoperative follow-up in combination with pathological examination

Texture Analysis of Brain Function with Fractal Dimension in Patients with Diffuse Encephalopathy.

BrainPET\u270

Texture Analysis of Brain Function with Fractal Dimension in Patients with Diffuse Encephalopathy.

BrainPET\u270