[A case of splenic inflammatory pseudotumor].

A 74-year-old woman underwent abdominal echography at a local clinic and a splenic mass was found. She was hospitalized for detailed examinations and treatment. Splenectomy was performed to make a definite diagnosis and for treatment because a definitive diagnosis could not be made, despite various examinations. Histopathological examination revealed that the lesion was infiltrated by polyclonal lymphoid cells and contained proliferating spindle-shaped fibroblasts without any atypical cells, so the splenic mass was diagnosed as an inflammatory pseudotumor. Because some cases of inflammatory pseudotumor can be diagnosed from the clinical course and imaging findings, this possibility should also be considered in the differential diagnosis of a splenic mass.

Dynamic US contrast study of the liver: Vascular and delayed parenchymal phase.

We evaluated the time-intensity curves of the ultrasound contrast agent, Levovist, in the aorta, portal vein and liver parenchyma in order to define distribution of the agent when it is administered by an intravenous bolus injection. Twelve healthy volunteers were studied. All 12 subjects were examined for the study of vascular phase and five of the subjects were examined for the study of delayed parenchymal phase. To evaluate vascular enhancement, transverse abdominal scanning was performed. To evaluate parenchymal enhancement, liver scanning was done just once at 14 time points up to 60 min after injection. The time-intensity curves in the aorta and the portal vein indicated the conventional curves of blood pool agents such as iodine CT agents and gadolinium MRI agents. They showed steep initial rises and peaks at 20 s and 30 s after injection, respectively. Parenchymal enhancement reached a peak five minutes after injection, with a plateau for 20 min subsequently. It has been proved that there are two phases of Levovist contrast ultrasonography, the vascular phase and the delayed parenchymal phase.

Preoperative RFA simulation for liver cancer using a CT virtual ultrasound system.

We developed a computed tomography (CT) virtual ultrasound system (CVUS) as an imaging system to support treatment under percutaneous ultrasound (US) guidance. This prototype clinical system, produced in collaboration with Tokyo Medical University, uses display software developed by Toshiba Medical Systems. We examined the utility of this system by scheduling treatment plans preoperatively and simulating puncture and radiofrequency ablation (RFA) for liver cancer. The study enrolled 51 liver cancer patients with 66 nodules 0.8-8cm in diameter in which RFA was performed between June 2004 and December 2004. Virtual US and multiplanar reconstruction (MPR) images were constructed on the basis of DICOM CT data and puncture and ablation of liver cancer were simulated. The following were evaluated: (1) how to avoid complications and determine an appropriate puncture route by simulating puncture with C-mode MPR images; (2) determination of the three-dimensional location of the tumor for ablation, as well as the adjacent organs and vessels, by MPR rotation 360 degrees around the center of the tumor (center lock); and (3) how to determine the center and volume of ablation and avoid injuries to nearby organs and vessels by simulating ablation procedures. C -mode MPR images were effective for (1) determining and modifying the puncture route in 35 of 51 cases (69.6%) and (2) determining the spatial location of vessels and nearby organs in 50 of 51 cases (98.0%) by the center lock; and (3) simulating the ablation helped determine the center and volume of ablation by avoiding injuries to vessels and nearby organs in 45 or 51 cases (88.2%). Taken together, the CVUS allowed easy simulation of local treatment of liver cancer under US guidance using CT data alone and the preoperative simulation predicted an improvement in the safety of local therapy of liver cancer.

Usefulness of contrast-enhanced ultrasonography with a new contrast mode, Agent Detection Imaging, in evaluating therapeutic response in hepatocellular carcinoma treated with radio-frequency ablation therapy.

Objective: The therapeutic response of radio-frequency ablation (RFA) for hepatocellular carcinoma (HCC) was evaluated by contrast-enhanced ultrasonography (US) using a new contrast mode, agent detection imaging (ADI), and its usefulness was compared with that of dynamic computed tomography (CT). Materials and methods: Forty patients with 64 nodules diagnosed as HCC histologically and/or by various imaging modalities were evaluated with ADI (1 and 7 days after treatment) and Dynamic CT (7 days after treatment). Results: ADI and dynamic CT revealed residual lesions in 15 and 12 nodules, and no residual lesions in 45 and 52 nodules, respectively. ADI yielded indeterminate findings in four nodules; although the vascular phase showed minute residual tumor vessels, the tumor appeared to be completely contained within the ablated area in the delayed phase. In these indeterminate cases, US-guided biopsies of the areas of residual vascularity revealed no viable cancer cells; only degenerated tissues. Conclusion: In assessing the therapeutic response of RFA for HCC, ADI has a similar competence to dynamic CT. Even if the vascular phase of contrast-enhanced US shows minute residual vessels, as long as the tumor is safely contained within the ablated area in the delayed phase, the cancer cells are likely to be degenerated.

Differential diagnosis of hepatic nodules using delayed parenchymal phase imaging of levovist contrast ultrasound: comparative study with SPIO-MRI.

T2-weighted fast spin echo images and T2*-weighted gradient-echo images of superparamagnetic iron oxide magnetic resonance imaging (SPIO-MRI) have been reported to reflect the number and function of macrophages in reticuloendothelial organs and be useful to differentiate malignant tumors from benign nodules of liver. We tried to prove that contrast-enhanced ultrasound can diagnose hepatocellular carcinoma (HCC) by comparing the findings of SPIO-MRI and the findings of the liver parenchyma on the delayed parenchymal phase of ultrasound imaging using the intravenous contrast agent Levovist, not through the evaluation of vascular imaging. Forty-six patients (52 nodules) with histopathological diagnosis of hepatic tumors were studied. They consisted of 11 non-malignant nodules (six regenerative nodules and five dysplastic nodules) and 41 HCC. All the patients were examined by Levovist contrast-enhanced ultrasonography and SPIO-MRI. The delayed liver parenchymal images of contrast-enhanced ultrasound using the intravenous contrast agent Levovist were similar to those observed on SPIO-MRI. The similarity of both findings suggests that delayed phase imaging by Levovist is closely related to the number and function of Kupffer cells in liver tumors. The diagnostic accuracy of contrast-enhanced ultrasound for HCC was high (90.4%) demonstrating that it is as reliable as SPIO-MRI.

Targetability and intracellular delivery of anti-BCG antibody-modified, pH-sensitive fusogenic immunoliposomes to tumor cells.

We prepared tumor-specific immunoliposomes by coupling anti-BCG monoclonal antibodies to pH-sensitive fusogenic liposomes modified with succinylated polyglycidol (sucPG), in order to obtain efficient binding to, and endocytotic internalization into, the tumor cells. Mouse colon carcinoma 26 cells, which are known to share a common antigen with BCG, were used in in vitro experiments. BCG-sucPG immunoliposomes showed fusion ability under acidic conditions. Fluorescence microscopic observation indicated that BCG-sucPG immunoliposomes bound to colon 26 tumor cells and induced receptor-mediated endocytosis at 37 degrees C. Fusion assay by resonance energy transfer using N-(7-nitro-2-1,3-benzoxadiazol-4-yl) diacyl phosphatidylethanolamine and N-(lissamine rhodamine B sulfonyl) diacyl phosphatidylethanolamine suggested that fusion between BCG-sucPG immunoliposomes and endosomal and/or lysozomal membrane did occur. These results imply that the BCG-sucPG immunoliposomes transfer their content into the cytoplasm by fusing with the endosomal and/or lysozomal membrane after recognition of target cells and subsequent internalization into the cells by endocytosis.