Biomedical subjects

Daisuke Deguchi

Publications and source records attributed to Daisuke Deguchi.

5 recordsLinked to original sources

PubMed2006

Evaluation of a prostate biopsy strategy for cancer detection using a computer simulation system with virtual needle biopsy for three-dimensional prostate models.

AIM: We evaluated a prostate biopsy strategy for cancer detection using a computer simulation system with virtual needle biopsy for three-dimensional (3D) prostate models. METHODS: Two 3D prostate models with a volume of 25 cc or 50 cc were constructed from computed tomographic images of radical prostatectomy specimens. The peripheral zone (PZ) and transition zone (TZ) were arranged in the prostate models according to the anatomical information. Four thousand patterns of cancer lesions were automatically inserted into each prostate model with a proportion of 75% in PZ and 25% in TZ. Average hit rates (AHR) in prostate models were evaluated both with an increased number of biopsy cores and various angles of virtual needle biopsy. The influence of adding secondary tumors for hit rates was also evaluated. RESULTS: For both sizes, the laterally angled biopsy in 4-8 core biopsy schemes showed higher AHR than the vertical plane biopsy, while the vertical plane biopsy in 10-18 core biopsy schemes showed higher AHR than the laterally angled biopsy. A higher number of biopsy cores increased the AHR of secondary tumors. CONCLUSIONS: Our results suggest that it is important in prostate cancer detection to change the needle placement according to the number of biopsy cores and the size of the prostate.

Biopsy, Needle↗

PubMed2006

A method for bronchoscope tracking by combining a position sensor and image registration.

This paper describes a method for tracking a bronchoscope by combining a position sensor and image registration. A bronchoscopy guidance system is a tool for providing real-time navigation information acquired from pre-operative CT images to a physician during a bronchoscopic examination. In this system, one of the fundamental functions is tracking a bronchoscope's camera motion. Recently, a very small electromagnetic position sensor has become available. It is possible to insert this sensor into a bronchoscope's working channel to obtain the bronchoscope's camera motion. However, the accuracy of its output is inadequate for bronchoscope tracking. The proposed combination of the sensor and image registration between real and virtual bronchoscopic images derived from CT images is quite useful for improving tracking accuracy. Furthermore, this combination has enabled us to achieve a real-time bronchoscope guidance system. We performed evaluation experiments for the proposed method using a rubber phantom model. The experimental results showed that the proposed system allowed the bronchoscope's camera motion to be tracked at 2.5 frames per second.

Artificial Intelligence↗

PubMed2005

Comparison of regional cerebral blood flow in patients with anorexia nervosa before and after weight gain.

We investigated changes in regional cerebral blood flow (rCBF) before and after weight gain in patients with restrictive anorexia nervosa (AN-R) in comparison with findings in normal subjects. We assessed resting rCBF using single photon emission computed tomography with technetium-99m hexamethylpropylene amine oxime in 12 AN-R patients and 11 controls. Each patient was examined at two time points, at the beginning of treatment and after weight gain (average examination interval=88+/-26 days). Control subjects were examined only once. Before treatment, the AN-R group had lower rCBF in the bilateral anterior lobes, including the anterior cingulate cortex (ACC), and in the right parietal lobe, the insula, and the occipital lobes. After weight gain, the patients showed significant increases in the right parietal lobe and decreases in the basal ganglia and cerebellum in accordance with significant improvement in body weight and eating attitudes. However, they showed persistent decreases in the ACC area even after weight gain compared with findings in the controls. A significant positive correlation was observed between body mass index and rCBF in the occipital lobes in the patients. These results suggest that weight gain is associated with a normalization of rCBF in a number of brain areas, but that the low level of rCBF in the ACC at baseline is unaffected by treatment in AN-R.

Adolescent↗

PubMed2005

Hybrid bronchoscope tracking using a magnetic tracking sensor and image registration.

In this paper, we propose a hybrid method for tracking a bronchoscope that uses a combination of magnetic sensor tracking and image registration. The position of a magnetic sensor placed in the working channel of the bronchoscope is provided by a magnetic tracking system. Because of respiratory motion, the magnetic sensor provides only the approximate position and orientation of the bronchoscope in the coordinate system of a CT image acquired before the examination. The sensor position and orientation is used as the starting point for an intensity-based registration between real bronchoscopic video images and virtual bronchoscopic images generated from the CT image. The output transformation of the image registration process is the position and orientation of the bronchoscope in the CT image. We tested the proposed method using a bronchial phantom model. Virtual breathing motion was generated to simulate respiratory motion. The proposed hybrid method successfully tracked the bronchoscope at a rate of approximately 1 Hz.

Algorithms↗

PubMed2003

A characteristic reactive hypoglycemia induced by rapid change of eating behavior in anorexia nervosa: a case report.

UNLABELLED: The relationship among reactive hypoglycemia, corresponding insulin metabolism, and eating behavior in anorexia nervosa (AN) has not been well documented. METHOD: A 22-year-old woman with AN was admitted to Kagoshima University Hospital. An oral glucose tolerance test was performed with additional sampling at 15 minutes on the seventh hospital day when her daily caloric intake rapidly increased, reaching 2,000kcal perday. RESULTS: An elevated level of insulin secretion (1,190pmol/L) was observed during the very early phase (15 minutes) after glucose load, whereas corresponding blood glucose elevations were not as high (1.2mmol/L). The patient experienced asymptomatic hypoglycemia (2.1mmol/L). CONCLUSIONS: Our findings suggested that a rapid increase of energy intake might cause reactive hypoglycemia with characteristic insulin metabolism, that is, an elevated level of insulin secretion during the very early phase.

Adult↗