Keigo Endo

The aim of this study was to develop the near infrared fluorescence (NIRF)-based imaging agent for the visualization of vascular endothelial growth factor (VEGF) in colon cancer. AlexaFluor 750 conjugating with bevacizumab, and injected intravenously into nude mice bearing VEGF over-expressing HT29 human colorectal cancer. Optical imaging was performed at 15 min, 24 h and 48 h post injection. Immunofluorescences staining of the tumor sections were performed. HT29 colorectal cancer xenografts were clearly visualized with bevacizumab-AlexaFluor 750. Ex vivo analysis showed 2.1 ± 0.4%, 37.6 ± 6.3% and 38.5 ± 6.2% injected dose/g accumulated in the tumors at 15 min, 24 h and 48 h respectively. Tumor uptake was significantly decreased in pretreated with excess of bevacizumab (p = 0.002). Immunofluorescence analysis showed strong staining of anti-CD 31 antibody around the blood vessels. Anti-VEGF-A and bevacizumab showed heterogeneous expression throughout the tumor. Current study successfully detected the VEGF expression in HT29 colorectal cancer xenografts, signifying as a potential agent for non-invasive imaging of VEGF expression, which may be applied in clinical practice.

Optimisation of computed tomography (CT) parameters is important in avoiding excess radiation exposure. The aim of this study is to establish the diagnostic reference levels (DRL) of CT in Japan by using dose–length product (DLP). Datasheets were sent to all hospitals/clinics which had CT scanner(s) in Gunma prefecture. Data were obtained for all patients who underwent CT during a single month (June 2010), and the distributions of DLP were evaluated for eight anatomical regions and five patient age groups. The DRL was defined as the 25th and 75th percentiles of DLP. Datasheets were collected from 80 of 192 hospitals/clinics (26 090 patients). DLP for head CT of paediatric patients tended to be higher in Japan compared with DRLs of paediatric head CTs reported from the EU or Syria. Although this study was performed with limited samples, DLP for adult patients were at comparable levels for all anatomical regions.

The objective of this study was to demonstrate the feasibility of pancreatic perfusion computed tomography (CT) and review pancreatic perfusion measurements by various imaging modalities. Dynamic CT data from 8 patients (4 men; mean age, 64.8 [SD, 12.1] years; range, 40-80 years) with normal pancreas were analyzed using 2 analytical models: the maximum-slope and compartment-model methods. Literature search was also performed. Although the perfusion value estimated by the maximum-slope method (88.1 [SD, 42.1] mL/min per 100 mL) was significantly smaller than that of the compartment-model method (127.0 [SD, 70.5]; P < 0.001), there was a linear correlation between them (r = 0.97, P < 0.001). In the literature review, 15 studies that reported the absolute values of normal pancreatic perfusion, by using perfusion CT, dynamic magnetic resonance imaging, hydrogen gas clearance method, and 15O-H2O-positron emission tomography were found. The reported mean values of normal pancreatic perfusion ranged from 38.4 to 356 mL/min per 100 mL, and there was a great deal of individual variation. Perfusion CT may provide reliable perfusion measurements of the pancreas, and the normal value was estimated at around 100 mL/min per 100 mL with a great deal of individual variation. The maximum-slope method may provide a lower perfusion value compared with the compartment-model method.

To evaluate the role of computed tomography (CT) -guided needle biopsy and sodium iodide fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in the investigation of solitary pulmonary nodules (SPN), which are discovered on screening chest radiographs, and to determine the cost-effectiveness of these modalities. We have used decision-tree analysis models to assess the accuracy and cost-effectiveness of four strategies for the diagnosis and management of SPNs: CT alone strategy (baseline), CT plus FDG-PET strategy, CT plus FDG-PET plus CT-guided needle biopsy strategy, and CT plus CT-guided needle biopsy strategy. Reported values of prevalence of cancer, and sensitivity and specificity of each diagnostic modality were applied to the decision-tree models using Japanese health care costs. The prevalence of lung cancer among SPNs discovered on the lung cancer screening was less than 10%. In this prevalence, the strategies using CT-guided needle biopsy were the cost-effective alternatives to the CT alone strategy (cost saving was 436,470 yen - 456,478 yen per patient), and had higher accuracies (95-96% vs. 67%). Both effects were mainly the result of reducing the number of the candidates who undergo unnecessary thoracotomy for a benign SPN, and these results were true over a wide range of prevalence of cancer (0-55%). The cost saving and accuracy of the CT plus FDG-PET strategy (359,206 and 92%) were approaching to those of the strategies using CT-guided needle biopsy. The introduction of CT-guided needle biopsy and FDG-PET for the evaluation of SPNs, which are discovered on screening chest radiograph, is potentially cost-effective in Japan with high accuracy.

To determine whether and under what conditions fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) may be cost-effective in evaluating solitary pulmonary nodules depicted on lung cancer screening in Japan. Three decision models for differentiating lung cancer from benign nodules were compared: CT alone, PET alone, and CT plus PET. The various paths of each strategy were dependent on variables determined from a review of the medical literature. Costs were based on Japanese health insurance. The prevalence of lung cancer among solitary pulmonary nodules detected on lung cancer screening was less than 10%. For this prevalence, the CT-plus-PET model was the cost-effective alternative to the CT-alone model (cost savings were yen 64,000 per patient) and provided greater accuracy (0.90 vs. 0.84). Both of these effects were the result of reducing the number of candidates who undergo unnecessary CT-guided or bronchofiberscopic biopsies or thoracotomy for a benign pulmonary nodule. The CT-plus-PET strategy is accurate and cost-effective for the characterization of solitary pulmonary nodules detected on lung cancer screening in Japan.

BACKGROUND AND PURPOSE: Multifocal microhemorrhages have been reported to be commonly found in the brain of patients with systemic hypertension and spontaneous brain hemorrhage. The factors associated with these lesions detected on T2*-weighted gradient-echo images were examined to determine whether these lesions serve to indicate different types of microangiopathy and to predict a patient’s risk for symptomatic hemorrhage.