Biomedical subjects

Naoki Suzuki

Publications and source records attributed to Naoki Suzuki.

53 records · Page 3Linked to original sources

PubMed2003

Real-time 3D deformation imaging of abdominal organs in laparoscopy.

In laparoscopic surgery, surgeons encounter particular difficulties during the course of the operation. Due to the restricted view from the endoscope and the limited degree of freedom using forceps, surgeons find their movements impeded. It would be necessary to develop a support system to provide surgeons with improved laparoscopic vision. If real-time visualization of the abdominal anatomy is possible, it will be useful for accurate procedure and quantitative evaluation. In this paper, The laser-scan endoscope system acquires and visualizes the shape and texture of the area of interest in a flash of time. Results of in-vivo experiments on the liver of a pig verify the effectiveness of the proposed system.

Abdomen↗

PubMed2003

Development of a new three-dimensional endoscopic ultrasound system through endoscope shape monitoring.

We have developed a new three-dimensional (3D) endoscopic ultrasound system (EUS) with convex scanning echoendoscope to diagnose and navigate for endoscopic puncture using the 3D image. To detect the position of the probe and to monitor the shape of the scope inside the body, we use a fiber optic tracking system which is shaped like a ribbon (Shapetape, Measurand Inc.). The fiber optic tracking system could measure bend and twist at each position of the ribbon. The position of the tip of the echoendoscope is allotted to a 2D image, and the system can reconstruct and visualize a 3D image in real-time. We have reported results of our experimental studies and animal studies.

Endosonography↗

PubMed2003

4-dimensional computer-based motion simulation after Total Hip Arthroplasty.

This paper represents a novel 4-dimensional(4D) computer-based motion simulation system for patients having had Total Hip Arthroplasty(THA). By constructing the skeletal model of the patient's lower extremity and measuring daily motions, we simulated the movement of the inner structures including the skeleton and the artificial joint. This system visually represents not only the 3-dimensional(3D) anatomical structure but also the 4-dimensional dynamic functions that represent the time sequential transitions of the position of each component. Clinicians can get detailed information of the movement of the hip joint quantitatively and give precise guidance for the patients with regard to postoperative daily motions. The measurement error was evaluated by performing experiments using OpenMRI and the results indicated sufficient accuracy of this system. We believe that this system enables clinicians to reveal the causes of complications after THA and encourages the development of new surgical techniques, materials. and designs of prostheses.

Arthroplasty, Replacement, Hip↗

PubMed2003

Four-dimensional analysis of mandibular movements with optical position measuring and real-time imaging.

Mandibular movement findings have not always been useful in clinical, even though measuring techniques have improved. This is because there is no method to evaluate condylar movement including the position of the temporal bone. In this study, we have attempted to apply 3-dimensional imaging to mandibular movement data, and have developed a 4-demensional analysis system representing mandibular movements. In this system, the mandibular movement can be observed in real-time by using the CT dataset from a volunteer. As a result the relationship between the mandibular movement and the anatomic structures becomes clear.

Adult↗

PubMed2003

Development of Dynamic Spatial Video Camera (DSVC) for 4D observation, analysis and modeling of human body locomotion.

We have developed an imaging system for free and quantitative observation of human locomotion in a time-spatial domain by way of real time imaging. The system is equipped with 60 computer controlled video cameras to film human locomotion from all angles simultaneously. Images are installed into the main graphic workstation and translated into a 2D image matrix. Observation of the subject from optional directions is able to be performed by selecting the view point from the optimum image sequence in this image matrix. This system also possesses a function to reconstruct 4D models of the subject's moving human body by using 60 images taken from all directions at one particular time. And this system also has the capability to visualize inner structures such as the skeletal or muscular systems of the subject by compositing computer graphics reconstructed from the MRI data set. We are planning to apply this imaging system to clinical observation in the area of orthopedics, rehabilitation and sports science.

Human Body↗

PubMed2003

Development of an endoscopic robotic system with two hands for various gastric tube surgeries.

This paper presents the first report on an endoscopic robot with two manipulators which performed surgical work to resect the mucosal layer of the stomach of pigs without penetrating the body surface. We designed and developed an endoscopic surgical robot system which possesses two arm shaped manipulators for various kinds of surgery in the gastric tubes. The distal part of the manipulator functions as forceps and they are able to hold and handle soft tissues through the cooperative efforts of the right and left arms. And it is also able to incise the gastric wall by holding an electronic scalpel (brought in from the instrument channel) with the manipulator on the right side while opening the sectioning plane on the left side which was take out. With this system we succeeded in the mucosal resection of a large portion of the stomach wall of a pig during experimental surgery. It can be said that this is a new approach robotic surgery in the gastric tube with this kind of surgical robot.

Animals↗

PubMed2003

Dynamic deformation of elastic organ model and the VR cockpit for virtual surgery and tele-surgery.

This paper describes a deformable organ model suited for a real-time surgical simulation system. This proposed organ model allows us to perform surgical maneuvers such as pressing, pinching, various incisions, resection and to show the deformation of the inner structures such as blood vessels on our system. At the same time, we have been developing a VR cockpit suited for virtual surgery and tele-surgery. Using our cockpit, our system allows us to provide the users with an environment closely resembling the open surgery situation.

Computer Simulation↗

PubMed2003

Development of a data fusion system using color information for real-time intraoperative liver surface measurement.

The goal of our study is to develop a data fusion system, which enables surgeons to easily visualize the inner structures of elastic organs during open surgery. We chose the liver as the focus of this study due to its easily deformable nature and complex vascular structures. To do so, we propose using preoperative data and supplementary intraoperative data. We captured a sequence of liver surface data for the intraoperative data by using trinocular stereo and we applied them to the preoperative 3D model's surface. Then, we modified the model to fit the intraoperative liver condition and portrayed the model's inner structures. With this method, we could establish this system.

Animals↗

PubMed2003

Real-time volumetric deformation for surgical simulation using force feedback device.

We have aimed to develop a virtual surgery system that realizes the performance of surgical maneuvers on elastic organs and to construct an elastic organ model known as sphere-filled model. In this paper we describe a new method of deforming volumetric data in real time by using sphere-filled model. As well we modified this model to take the interference between soft tissue and rigid tissue to consideration. Furthermore basic surgical maneuvers (pushing, pinching and incision) and connection with force feedback device are realized on this model similarly to our surface model.

Computer Simulation↗

PubMed2002

A novel 3-dimensional EUS technique for real-time visualization of the volume data reconstruction process.

BACKGROUND: Three-dimensional EUS (3D-EUS) technology has facilitated spatial interpretation of US images. However, acquisition of consecutive US scans is time consuming and difficult. A new 3D-EUS system was developed that negates this problem by allowing rapid image renewal and the efficient production of consecutive US scans. METHODS: Three-dimensional images were reconstructed from a series of 2-dimensional images corresponding to the rotation angle of the echoendoscope as measured with an electromagnetic tracking system. To evaluate the technical feasibility of the system, 3-dimensional images of splenic veins in 2 patients and an esophageal submucosal tumor in a third patient were generated. RESULTS: The 3D-EUS system acquired image data at a rate of 30 frames per second and allowed visualization of these data in real-time. The area of interest was clearly and rapidly portrayed in all 3 patients. CONCLUSION: This study demonstrates the efficiency of the new 3D-EUS system described in this report. Further development of this novel 3D-EUS system may lead to new applications of this technology.

Computer Systems↗

PubMed2002

Three-dimensional image analysis of a head of the giant panda by the cone-beam type CT.

The cone-beam type CT (Computed Tomography) enabled us to collect the three-dimensional (3D) digitalized data directly from the animal carcass. In this study, we applied the techniques of the cone-beam type CT for a carcass head of the giant panda (Ailuropoda melanoleuca) to obtain the 3D images easily without reconstruction process, and could morphologically examine the sections from the 3D data by means of non-destructive observations. The important results of the study represent the two following points. 1) We could show the morphological relationships between the muscles of mastication and the mandible in non-destructive status from the 3D data. The exact position of the coronoid process could be recognized in the rostro-lateral space of the temporal fossa. 2) By the serial sections from the 3D data sets, the morphological characteristics in the nasal cavity were detailed with high resolution in this rare species. The nasal concha was well-developed in the nasal cavity. The ethmoidal labyrinth was encountered immediately caudal to the nasal cavity and close to the region of the olfactory bulb. The ethmoidal labyrinth consisted of the complicated osseous structure in this area. The data will be useful to discuss the olfactory function in the reproduction behavior of this species.

Animals↗

PubMed2002

Predictors of recurrent restenosis after coronary stenting: an analysis of 197 patients.

One of the major limitations in coronary stenting is in-stent restenosis. This study was aimed to identify clinical, angiographic, and procedural factors that may be related to recurrent in-stent restenosis. We analyzed consecutive 197 patients who underwent coronary stenting. Follow-up angiography was available in 170 patients and repeat balloon angioplasty was performed for in-stent restenosis. These patients were subdivided into 3 groups: group A consisted of 100 patients that were never restenosed, group B had 49 patients restenosed once, and in group C were 21 patients restenosed more than twice. Group C was more often female (48%) and included diabetes mellitus patients (52%). Lesion location, reference vessel size and diameter stenosis were similar for all groups. However, the incidence of calcified lesions tended to be higher (50% vs. 29%; p = 0.07), and lesion length was longer in group C than in group A (11.9+/- 5.4 mm vs. 9.0+/- 3.9 mm; p < 0.01). Diameter stenosis after predilation as well as after stenting was significantly higher in group C than in group A (50+/- 10% vs 39+/- 10%; p < 0.01, 32+/- 8% vs. 19+/- 10%; p < 0.01). The incidence of diffuse type of in-stent restenosis was significantly higher in group C than in group B (62% vs. 14%; p < 0.01). Multivariate logistic regression analysis identified diameter stenosis after stenting (p = 0.0022), female (p = 0.0135), and diameter stenosis after predilatation (p = 0.0233) as the significant correlate of recurrent in-stent restenosis. In conclusion, the major recurrent in-stent restenosis predictors identified included female gender, final diameter stenosis, and diameter stenosis after predilatation.

Aged↗

PubMed2002

[A case of neuralgic amyotrophy manifesting bilateral anterior interosseous nerve syndrome].

A 49-year-old woman acutely developed severe bilateral shoulder pain followed by weakness of the right shoulder girdle muscles. Within a few days, an inability to flex the terminal phalanges of the bilateral thumbs and index fingers emerged. Neurologic examination 1 month after the onset of symptoms showed atrophy of the right shoulder girdle muscles and mild decreased cutaneous sensation in the distribution of the right axillary nerve. Needle electromyography examination at this time showed fibrillation potentials in the right deltoid and bilateral flexor pollicus longus muscles. Recruitment of the right deltoid, supra- and infraspinatus muscles was reduced. Motor unit potentials in these muscles were of normal configuration. Nerve conduction studies in the upper limb were normal. She was diagnosed as neuralgic amyotrophy with bilateral anterior interosseous nerve syndrome. 4 months later, the muscles innervated by the bilateral anterior interosseous nerve improved in the muscle strength. Clinical features of this case were compatible with a mononeuropathy multiplex form of neuralgic amyotrophy associated with an autoimmune etiology. We think this case is important for speculating the pathogenesis of neuralgic amyotrophy. This case reminds us that patients with neuralgic amyotrophy sometimes demonstrate anterior interosseous nerve syndrome and most patients manifesting anterior interosseous nerve syndrome are patients with neuralgic amyotrophy.

Brachial Plexus Neuritis↗

PubMed2002

Intraoperative 3D shape recovery of abdominal organs for laparoscopic data fusion.

Precise measurements of geometry should accompany robotic equipments in operating rooms if their advantages are further pursued. For deforming organs including the liver, intraoperative geometric measurements play an essential role in computer surgery in addition to pre-operative geometric information from CT/MRI. The laser-scan endoscope system acquires and visualizes the shape of the area of interest in a flash of time. Results of in-vivo experiments on the liver of a pig verify the effectiveness of the proposed system. In the next stage, we aim to make a data-fusion in laparoscopy.

Animals↗

PubMedDate not supplied

Volumetric cine imaging for cardiovascular circulation using prototype 256-detector row computed tomography scanner (4-dimensional computed tomography): a preliminary study with a porcine model.

This is a preliminary demonstration of volumetric cine imaging of cardiovascular circulation in domestic pigs using a prototype 256-detector row computed tomography (CT) scanner. The scan range is approximately 120 mm in the craniocaudal direction, with a 0.5-mm slice thickness. The thin sections can be used to create cine loops in multiple planes. Thus, the 256-detector row CT scanner overcomes some of the limitations of present helical CT methods.

Animals↗

PubMedDate not supplied

Real-time volumetric imaging of human heart without electrocardiographic gating by 256-detector row computed tomography: initial experience.

OBJECTIVE: The feasibility of human cardiac imaging using a prototype 256-detector row cone-beam computed tomography (256CBCT) scanner without electrocardiographic gating was examined. METHODS: Two healthy male volunteers were examined by contrast-enhanced 256CBCT. The number of detectors was 912 x 256, each measuring approximately 0.5 mm x 0.5 mm at the center of rotation. The craniocaudal coverage was approximately 100 mm after reconstruction by the Feldkamp-Davis-Kress algorithm. The effective time resolution was 500 milliseconds using a half-scan algorithm. RESULTS: Serial enhancement of the left ventricular myocardium was detected. The right and left coronary arteries at proximal and distal segments were depicted without significant blurring. Although the left ventricular wall motion on cine images was not smooth over time, it was possible to measure ventricular volume and ejection fraction. CONCLUSIONS: Using the 256CBCT, it was possible to visualize the coronary arteries, myocardial perfusion, and ventricular contraction simultaneously during a single acquisition.

Algorithms↗

PubMedDate not supplied

Informatics in Radiology (infoRAD): mobile wireless DICOM server system and PDA with high-resolution display: feasibility of group work for radiologists.

A novel mobile system has been developed for use by radiologists in managing Digital Imaging and Communications in Medicine (DICOM) image data. The system consists of a mobile DICOM server (MDS) and personal digital assistants (PDAs), including a Linux PDA with a video graphics array (VGA) display (307,200 pixels, 3.7 inches). The MDS weighs 410 g, has a 60-GB hard disk drive and a built-in wireless local area network (LAN) access point, and supports a DICOM server (Central Test Node). The Linux-based MDS can be accessed with personal computers (PCs) and PDAs by means of a wireless or wired LAN, and client-server communications can be established at any time. DICOM images can be displayed by using any PDA or PC by means of a Web browser. Simultaneous access to the MDS is possible for multiple authenticated users. With most PDAs, image compression is necessary for complete display of DICOM images; however, the VGA screen can display a 512 x 512-pixel DICOM image almost in its entirety. This wireless system allows efficient management of heavy loads of lossless DICOM image data and will be useful for collaborative work by radiologists in education, conferences, and research.

Computers, Handheld↗