This paper presents a three-dimensional electronic laparoscopy system, including three-dimensional laparoscope pipe and medical video system. The three-dimensional laparoscope pipe adopts a dual-optical structure, which can collect three-dimensional information of the surgical region. By selecting a reasonable initial structure, the MTF curve of the objective lens is close to the diffraction limit, and the distortion is less than 25%. The medical video system also achieved high-definition image with 1 080 P, 30 Hz by GPU. At the mean time, the three-dimensional electronic laparoscope has achieved quantitative production and has been tested in a number of animals, which has broad application prospects and significant clinical application value.
Electronics, Medical ; Imaging, Three-Dimensional ; Laparoscopes ; Laparoscopy

Medical students and doctors should study the appearance of normal anatomical structures in the magnetic resonance images (MRIs). For this purpose, horizontal, coronal, sagittal MRIs of a healthy entire body and corresponding segmented images were prepared. However, it is inconvenient to select interesting MRIs and segmented images; and it is difficult to understand how stereoscopic anatomical structures appear in the MRIs. Therefore, in this research, a software, on which interesting MRIs can be conveniently displayed among the horizontal, coronal, sagittal MRIs and corresponding segmented images can be displayed together, was composed. And after stacking the segmented images, three-dimensional (3D) image of each anatomical structure was manually reconstructed by surface rendering. Then another software, on which interesting 3D images of anatomical structures can be displayed and rotated, was composed too. These softwares are expected to help medical students and doctors understand normal anatomical structures in the MRIs and read pathological findings in the MRIs of patients.
Humans ; Imaging, Three-Dimensional* ; Magnetic Resonance Imaging* ; Students, Medical

No abstract available.
*Diagnostic Imaging ; Human ; Radiology/*trends ; Radiology, Interventional ; Specialties, Medical

This paper mainly introduces the material composition and structure of two kinds of compound tabletop which currently used in large medical imaging equipment, also introduces the proper material choosing and production processing, together with the advantage and shortage of this two kinds of tabletop and different application occasion.
Construction Materials ; Diagnostic Imaging ; instrumentation ; Durable Medical Equipment

PURPOSE: Diffusion-weighted magnetic resonance imaging (DWI) has been known to visualize hyperacute ischemic stroke. And it takes only a few minutes to do. Moreover only a small amount of time and little cost is required to add T2-weighted imaging (T2WI) to DWI. The purpose of this study is to determine the usefulness of T2WI in addition to DWI as a primary imaging modality for patients with suspected ischemic stroke. METHODS: DWI plus T2WI was performed from January to May 2001 on the patients with suspected ischemic stroke. Two emergency physicians reviewed the films and medical records. The sensitivity and the specificity of DWI and T2WI for acute ischemic stroke were calculated. The agreement between DWI and T2WI was calculated using kappa statistics. RESULTS: A total of 241 patients were enrolled. Acute ischemic stroke was confirmed in 86 (35.7%) patients. The sensitivity and the specificity of DWI for acute ischemic stroke were 94.2% and 98.7%, and those for T2WI were 60.5% and 94.2%, respectively. The kappa value was 0.721 (p<0.01). Among the 86 acute ischemic stroke patients, the number of cases who presented less than 6 hours after symptom onset was significantly lower in the T2WI positive group (31% vs. 68.7%, p<0.05). CONCLUSION: This study suggests that the addition of T2WI to DWI as a primary imaging modality for acute ischemic stroke has little benefit compared to DWI alone, especially, when the symptom duration has been less than 6 hours.
Emergencies ; Humans ; Magnetic Resonance Imaging* ; Medical Records ; Sensitivity and Specificity ; Stroke*

This study presents an electronic portal imaging devices (EPIDs) based on daily check tool for Linac that is usable for different cancer centers.Several images of open rectangle fields were acquired with EPID and the key items of daily Linac check were derived from the obtained images using an in-house developed automatic analysis software.The experiment results showed that each parameter calculated by this tool is as reliable as the corresponding result measured by the commercial quality assurance devices and its measuring efficiency is much higher.
Electronics, Medical ; Electrons ; Particle Accelerators ; Phantoms, Imaging ; Radiometry ; Software

Image registration methods based on mutual information, including mutual information and normalized mutual information, have been accepted as the most accurate and efficient methods. But there are many fluctuations in the registration functions that hinder the optimization procedure and lead to registration failure in intra-modal registration. We found that besides the interpolation artifacts, the uncertainty of the changing of entropy with the changing of overlap also contributes to the fluctuations. The effect of interpolation artifacts can be eliminated, but it is difficult to eliminate the effect of uncertainty of entropy. Luckily, this effect is not significant in normalized mutual information. Normalized mutual information is more stable and robust than standard mutual information and its better performance and wider application can be expected.
Algorithms ; Diagnostic Imaging ; Humans ; Image Processing, Computer-Assisted ; methods ; Magnetic Resonance Imaging ; methods ; Medical Informatics ; methods ; Registries

PURPOSE: To evaluate the incidence of secondary contiguous or non-contiguous subchondral bone impactions (SBI) in subaxial cervical spinal injury and associated primary injury patterns. MATERIALS AND METHODS: A retrospective review of computed tomography, magnetic resonance imaging, and medical records was carried out for 47 patients who had sustained a subaxial cervical spinal injury. Presence, number, level, and sites of secondary contiguous or non-contiguous SBI were recorded. To evaluate primary injury patterns, the level and number of primary injury sites of subaxial cervical spine injury, injury morphology, anterior/posterior discoligamentous complex (ADC/PDC) injury, posterior ligamentous complex (PLC) injury, spinal cord injury, and mechanism of injury (MOI) were analyzed. Differences in primary injury pattern of subaxial cervical spine injury and MOI between patients with and without SBI, and between contiguous or non-contiguous SBI were analyzed using the Mann-Whitney U test, Pearson's chi square test and Fisher's exact test. RESULTS: Eighteen patients (18/47, 38.29%) had developed contiguous (n=9) or non-contiguous (n=9) SBI, most commonly involving T3 (15/47, 31.91%) and 3 levels (6/18, 33.33%). All SBIs had developed near the anterosuperior region of the body and the superior endplate and were the result of a high-impact MOI. SBIs were statistically significant in association with injury morphology and PLC injury (P=0.001, P=0.009, respectively) at the primary injury site. Non-contiguous SBI was more frequently accompanied by upper cervical spinal injuries in association with PDC injuries, as opposed to contiguous SBI, with statistical significance (P=0.009), while no other statistically significant differences were found. CONCLUSION: Secondary SBIs are common and probably associated with subaxial cervical spinal injuries with high energy compressive flexion forces.
Humans ; Incidence* ; Ligaments ; Magnetic Resonance Imaging ; Medical Records ; Retrospective Studies ; Spinal Cord Injuries ; Spinal Injuries* ; Spine

For identifying the pathological findings in magnetic resonance images (MRIs), normal anatomical structures in MRIs should be identified in advance. For studying the anatomical structures in MRIs, a learning tool that includes the followings is necessary. First, MRIs of the entire body; second, horizontal, coronal, and sagittal MRIs; third, segmented images corresponding to the MRIs; fourth, three dimensional (3D) images of the anatomical structures in the MRIs; fifth, software incorporating the MRIs, segmented images, and 3D images. Such a learning tool, however, is hard to obtain. Therefore, in this research, such a learning tool which helps medical students and doctors study the normal anatomical structures in MRIs was made as follows. A healthy young Korean male adult with standard body shape was selected. Six hundred thirteen MRIs of the entire body were scanned (slice thickness 3 mm, interslice gap 0 mm, field of view 480 mm x 480 mm, resolution 512 x 512, T1 weighted), and transferred to the personal computer. Sixty anatomical structures in the MRIs were segmented to make segmented images. Coronal, sagittal MRIs and coronal, sagittal segmented images were made. On the basis of the segmented images, forty-seven anatomical structures' 3D images were made by manual surface reconstruction method. Software incorporating the MRIs, segmented images, and 3D images was composed. This learning tool that includes horizontal, coronal, sagittal MRIs of the entire body, corresponding segmented images, 3D images of the anatomical structures in the MRIs, and software is expected to help medical students and doctors study the normal anatomical structures in MRIs. This learning tool will be presented worldwide through Internet or CD titles.
Adult ; Humans ; Internet ; Learning ; Magnetic Resonance Imaging* ; Male ; Microcomputers ; Students, Medical

PURPOSE: To describe the MR features of intraspinal cysticercosis. MATERIALS AND METHODS: Medical records and MR images of four cases of intraspinal cysticercosis were retrospectively reviewed. The MR findings were described with regard to the location and signal intensity of the lesions, contrast enhancement, presence or absence of associated intracranial cysticerci, and other findings. RESULTS: There were three cases of subarachnoidal form and one case of intramedullary form. Cysticerci of subarachnoidal form in three cases were located in retromedullary space at C2 level, anterior to cord at C1 -C6 levels, and lumbosacral area, respectively. The signal intensities of the lesions were same as those of CSF. Localized arachnoidal enhancement was found in all three cases. In one case there was a large area of high signal intensity within the spinal cord on T2 weighted image suggesting either ischemia secondary to vascular compromise or inflammatory edema. All of these three cases accompanied intracranial cysticercosis. Intramedullary cysticercosis in one case was shown as a single I cm cystic lesion at C2 level, which showed hypointense signal on T1 weighted image, hyperintense signal on T2-weighted image, and signet-ring-like enhancement. This lesion did not accompany intracranial cysticerci. CONCLUSION: lntraspinal cysticercosis manifested as single or multiple cysts within either spinal cord or subarachnoid space, and were frequently associated with arachnoiditis.
Arachnoid ; Arachnoiditis ; Cysticercosis* ; Edema ; Ischemia ; Magnetic Resonance Imaging* ; Medical Records ; Retrospective Studies ; Spinal Cord ; Subarachnoid Space