Biomedical subjects

Yukihiro Matsuura

Publications and source records attributed to Yukihiro Matsuura.

4 recordsLinked to original sources

PubMed2006

Development of a method for reconstructing three-dimensional data from axial, sagittal, and coronal MR images.

Magnetic resonance (MR) imaging is useful for the diagnosis of brain atrophy and intracranial abnormalities. We have developed a method of automated volumetry to evaluate the degree of brain atrophy for the diagnosis of dementia. Whole-brain MR images with thin slices without gaps are required for segmentation and volumetry. However, obtaining such images requires that the patient remain at rest for a prolonged period, thereby reducing the throughput of MR imaging examinations. Therefore, a method is needed for the reconstruction of isotropic three-dimensional (3D) data using routine axial, sagittal, and coronal MR images with 30% gaps and measurement of brain volume. The method of reconstructing 3D data consists of four processes: 1) segmentation of the brain region on axial, sagittal, and coronal MR images using the region-growing technique; 2) setting data to a 3D domain; 3) registration by manual operation; and 4) interpolation between the data based on linear interpolation. In clinical MR images, the differences between this method and the conventional technique were less than 10%. These results demonstrate that this technique is able to construct 3D data from axial, sagittal, and coronal MR images.

Adult↗

PubMed2005

[Study of automated segmentation of the cerebellum and brainstem on brain MR images].

MR imaging is an important method for diagnosing abnormalities of the brain. This paper presents an automated method to segment the cerebellum and brainstem for brain MR images. MR images were obtained from 10 normal subjects (male 4, female 6; 22-75 years old, average 31.0 years) and 15 patients with brain atrophy (male 3, female 12; 62-85 years of age, average 76.0 years). The automated method consisted of the following four steps: (1) segmentation of the brain on original images, (2) detection of an upper plane of the cerebellum using the Hough transform, (3) correction of the plane using three-dimensional (3D) information, and (4) segmentation of the cerebellum and brainstem using the plane. The results indicated that the regions obtained by the automated method were visually similar to those obtained by a manual method. The average rates of coincidence between the automated method and manual method were 83.0+/-9.0% in normal subjects and 86.4+/-3.6% in patients.

Adult↗

PubMed2005

[Visualization of the lower cranial nerves by 3D-FIESTA].

MR cisternography has been introduced for use in neuroradiology. This method is capable of visualizing tiny structures such as blood vessels and cranial nerves in the cerebrospinal fluid (CSF) space because of its superior contrast resolution. The cranial nerves and small vessels are shown as structures of low intensity surrounded by marked hyperintensity of the CSF. In the present study, we evaluated visualization of the lower cranial nerves (glossopharyngeal, vagus, and accessory) by the three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) sequence and multiplanar reformation (MPR) technique. The subjects were 8 men and 3 women, ranging in age from 21 to 76 years (average, 54 years). We examined the visualization of a total of 66 nerves in 11 subjects by 3D-FIESTA. The results were classified into four categories ranging from good visualization to non-visualization. In all cases, all glossopharyngeal and vagus nerves were identified to some extent, while accessory nerves were visualized either partially or entirely in only 16 cases. The total visualization rate was about 91%. In conclusion, 3D-FIESTA may be a useful method for visualization of the lower cranial nerves.

Accessory Nerve↗

PubMed2005

[Effect of saline flush using dual injector on abdominal dynamic contrast enhanced computed tomography].

PURPOSE: To evaluate the efficacy of the saline flush technique for abdominal multidetector-row computed tomography (CT). METHODS: As a clinical study, 147 patients with chronic hepatic disease were divided into two groups: group A, given 100 cc of contrast material flushed with 50 cc of saline; and group B, given 100 cc of contrast material only. The difference in attenuation values between groups A and B, and cirrhotic liver and non-cirrhotic liver were evaluated. As an in-vitro experimental study, time vs. peak pressure curve was obtained changing injection devices. RESULTS: Group B showed a greater contrast enhancement effect in the early arterial equilibrium phase of the aorta and late arterial phase of the liver. In cirrhotic liver, the aorta showed greater contrast enhancement in the early arterial phase in group A. Attenuation values of hypervascular hepatic nodules showed no statistically significant difference between groups A and B. Time to reach peak pressure was prolonged when using saline flush devices in vitro. Flow of contrast material from the contrast material cylinder to the saline cylinder was also discovered. CONCLUSION: Saline flush causes peak arterial contrast to be strong for a short duration. Abdominal organ attenuation values are not necessarily increased in the saline flush method. It is important to know that contrast enhancement is dependent on the injection device.

Aorta, Abdominal↗