Journal of Computer Aided Surgery Vol.5 No.3-2
Abstract: Recording surgical information is important , because it is useful
for various purpose, such as quantitiative validation of surgery and cleaning
up the causes of unexpected occurrence in an operation. However, quantity
and variety of recorded data become larger, it is more difficult to manage
and analyze it totally. we have been developing a total computer management
system of surgical information and a framework of surgery reporting. In
this paper, we propose a standard format for recording surgical information
and apply to various surgical navigation systems for ensuring its effectiveness.
Keywords: integration of surgical information, surgical navigation system,
surgery report, XML
Abstract: Breakdown of surgical robot systems can cause fatal trouble because
human work in the working area of these robot deffer from industrial robots.
So these system require high security and reliability. In this paper, we
propose the thchniques which realize the high security and reliability
of the surgical robot system, and enhance security and reliability of the
surgical robot system.
Keywords: Surgical Robot, Security, Reliability
Abstract: A cognitive analysis of the procedure of laparoscopic cholecystectomy
by the Rasmussen's model was performed in this study. Elemental operations
such as dissection, hemostasis and suturing were classified into "
skill based " behavior, and strategies for complication and unexpected
events were classified into "rule based " and "knowledge-based"
behaviors. Process analysis by Rasmussen's model is useful for work-analysis
of the surgical procedure in the resurch and development of surgical manipulators
and simulators.
Keywords: Rasmussen's cognitive model , process analysis, surgical procedure
Abstract: (Objective) A three-dimensional (3D) endoscope can provide stereopsis
, an important depth cue, but gazing at the stereoscopic display long time
is reported to give surgeons excessive visual fatigue. We studied its effect
on the laparoscopic manipulation, and evaluated it in both objective and
sensory scores. (Methods) A 3D laparoscope is used to provide both 2D and
3D visions, by switching video signals. 24 non-medical subjects performed
endoscopic tasks in 2D and 3D vision. In both visual conditions, subjects
repeatedly reach targets ( one randomly selected among ten) with the tip
of forceps for five minutes. Objective scores are evaluated by the average
time of each task. Sensory analysis includes questions about fatigue, depth
perception and stereopsis. (Results) We found significant improvement of
performance in subjects who performed tasks in 3D after 2D (p <0.01).
No improvement was observed in subjects who performed tasks in 2D after
3D (p > 0.10). Nine subjects could not correctly distinguish between
2D and 3D. (Conclusion) Although learning effect is dominant, 3D vision
improved laparoscopic performance. Sensory analysis needs further examination
with longer and complex tasks.
Keywords: depth perception, laparoscopy
Abstract: We propose the " Non-contact Stiffiness Imager for Endoscope"
that can detect the relative stiffiness as a visual pattern. The sensor
is conposed of an air-supply nozzle for imparting a force to the environment
and a CCD camera for detecting a pattern. The CCD camera obtains a contour
map pttern using the bringhtness distribution of the light source of endoscope.
In order to emphasize the change of brightness due to the displacement
of environment, we utilize the light saturation method where we focus on
the lower bit image for the obtained data multiplied by an appropriate
factor α.Basic experimental results using an endoscope are also shown.
Keywords: Endoscope, Non-contact, Air Flow, Stiffiness Imager, Contour
Map Pattern
Abstract: This paper introduces a laparoscope using wedge prisms that has
flexible viewpoint . Principle of this devise was reported in the 1st paper.
Ways to make size smaller and reduce eclipse were reported in the 2nd paper.
And estimation of image quality and how to make it move were reported in
the 3rd paper. In this paper, we report a new algorism to actuate the laparoscope
and evaluation of this algorism. Using the new algorism, the laparoscope's
viewpoint can move faster and more accurately than ever one. When it moves
to direction of 45 degree , average of positioning error is 1.2mm . Finally,
we report results of Pig experiments, the laparoscopic image was good without
noise, and it moved smoothly in the abdominal cavity.
Keywords: Laparoscope, Wedge Prism, Minimally invasive Surgery, Medical
Robot
Abstract: We developed an endoscope system that provides two different
views simultaneously, one is a wide view (120 degrees) and the other is
an enlarged view with image-shifting mechanism. As an additional this paper
the accuracy of the mechanism and a control feeling for the switch are
described.
Keywords: endoscope, image shift, dual-view
Abstract: A remote-contorolled endoscope positioning system, NaviotTM (Hitachi Ltd.), was newly developed and applied to an endoscopic surgery on 58 patients; laparoscopic cholecystectomy,splenectomy, inguinal herniorrhaphy, appendectomy, colectomy, Nissen fundplication , prostatectomy, sympathectomy, extirpation of mediastinal tumor, lobectomy, oophorectomy, hysterectomy. A surgeon could easily control the zoom and the 8 directions of the laparoscopic movement. NaviotTM replaced the surgeon who holds the camera , and enabled surgeons to perform " solo surgery " on laparoscopic inguinal herniorrhaphy and appendectomy.
Keywords: Remote-contorolled endoscope positioning system, Laparoscopic
inguinal herniorrhaphy, Solo surgery
Abstract: Convex type endoscopic ultrasound(EUS) has been recognized as
an essential device for hemodynamic analysis using its Doppler mode and
guide for various interventional diagnostic and therapeutic procedures
using needle puncture technique . The major disadvantage of convex type
EUS is the sector-shaped smaller longitudinal acoustic window. Examiner
must convey scanning only with guidance of this small acoustic window without
endoscopic view. Consequently, reproducibility of the convex type EUS is
not so high as other types of EUS. To overcome these difficulties , we
developed a three-dimensional convex type EUS (3D-CEUS) and previously
reported its clinical feasibility. In this study, we quantitatively evaluated
accuracy and reproducibility of 3D-CEUS in a phantom study. We will discuss
the accuracy and reproducibility of the system using results of the phantom
study and several clinical images.
Keywords: Endoscopic ultrasongraphy, animal study, three-dimensional image.
Abstract: Although Total Artificial Kidney(TAK) need to be realized for
the renal patient, the present condition is that even the basic form does
not exist. Various problems, such as material science , living body dynamism,
an osmosis film, and the casting method, are mentioned to this problem.
This study aims at designing the basic form of TAK using the design technique
from a viewpoint of a design. The basic form was approached from both directions
of a macroscopic viewpoint and a microscopic viewpoint, and the morphlogy
which introduced topology considered the substantiation.Consequently, the
concept of TAK was made into the distributed processing type artificial
kidney from the macroscopic viewpoint, and the form on the topology of
dogbone space was chosen as the form image. Morever, the automatically
generable form was used by the program to the pipe in the kidney which
changes while branching with micrometer from a millimeter. From the microscopic
viewpoint , the design image was given to the part which performs the important
function of the kidney; filtration and re-absorption.
Keywords: Total Artificial Kidney, Morphology , Topology, Dogbone Space,
Macroscopic and Microscopic Approach
Abstract: In recent years, the callus extending method is capturing the
spotlight as a care to aplasia and the deficit of a jawbone. We develop
the embedding type automatic extension machine equipped with many merits
compared with the conventional manual extension machine. Moreover,we examine
the system in which monitoring of somewhere is possible by using a network.
Keywords: distraction osteogenesis, mandibular lengthening, teleoperation,
mechatronics, network
Abstract: Optically driven micromachine were made by use of two-photon
microstereolithography with 140 nm resolution. The nanoneedle is attached
to a dot named " Optical trap point" to control the movement
just by a single laser beam . Since the driving performance of the nanoneedle
depends on laser power and the shape and size of the optical trap point
, we have developed the laser manupulation system using hight power YAG
laser and optimized the diameter and the height of column-like optical
trap point. By the laser manupulation system and the optimization of the
optical trap point , the nenoneedle offers the torque on the order of fN
to pN. The driving frequency of translational motion was also attained
to 12 Hz. Such optically driven nanotools will be widely applied to micro/nano
biotechnology.
Keywords: Optically driven micromachine, Two-photon Absorption, Microstereolithography,
Laser Trapping
Abstract: We have developed a novel three-dimensional micro fabrication
process with high-resolution and high-speed for biodegradable polymers.
The designed system allows us to process micro-level forms by extruding
and scanning heated and melted polymers from the nozzle. We adopted a batch
process to supply materials in order to eliminate the prior process that
employs toxic solvents. In addition , we are able to handle almost all
the biodegradable thermoplastic resins by adopting this system . To realize
high-accuracy, we design very small-opening nozzle with highly customized
fabrication parameters. This renders it possible to process with the resolution
of 50 μm. Poly (lactide)(PLA) enables us to process millimeter-sized structures
such as micro pipes, bending pips, and coil springs in less than 10 minutes.
The shape of the structures can be easily changed and quickly modified
. Our system is expected to have potential applications in optimum design
and fabrication of implantable devices.
Keywords: Biodegradable , Three-dimentional , Microfabricationk High-resolution
Abstract: We have developed a robotic system for the reduction of bone
fracture. In this paper, we describe an image-based navigation system as
a component of the robotic system. Voxel-based 2-D/3-D registration and
volume registration techniques are employed for the detection of bone fragment
positions and the determination of reposition path, respectively. All coordinate
systems are integrated in the navigation and then robot is controlled .
The results of accuracy validation by using computer simulation are shown.
Keywords: computer aided surgery, bone fracture reduction, 2-D/3-D registration,
volume registration
Abstract: The number of cases of femur fracture is increasing with progress
of an aging society year by year. The research of the robotic system and
navigation system is widely done in orthopedics. In these computer aided
systems,it is the one of the important subjects how to reduce fracture
accurately. In this study, we focused attention on the body symmetry, applied
fracture reduction planning using contralateral bone, and validated its
accuracy. In fracture reduction planning, we register between the mirror
image of the contralateral bone and the proximal or distal fragments using
the preoperative CT image, and calculate the relative positions the healty
bone. Using relative position and orientation of the healthy bone as the
ground truth, accurate validation is available. In the experiments, bias
of translation and rotation were 4.0 mm and 2.3 degrees and precision of
those were 0.23mm and 0.71degrees.
Keywords: fracture reduction,preoperative planning, contralateral bone,
volume registration
Abstract: A high-precision navigation system for Anterior Cruciate Ligament(ACL)
reconstruction is presented. In the system, 3D CT data is used to visualize
the structure of bones and optical localizer is used to detect the position
of femur, tibia and surgical tools. Since CT images are acquired preoperatively
and markers are fixed to bones intraoperatively, their relative position
has to be initialized. To achieve this initialization, 2D/3D registration
method between CT model and X-ray images was developed. The registration
is performed by minimizing the difference between contour lines. As ACL
reconstruction requires precision, three X-ray images taken from different
angles are used for the registration. Simulated registration shows the
mean error to be less than 1.5mm.
Keywords: image-guided surgery, navigation, 2D/3D registration, X-ray fluoroscopy,
CT
Abstract: Force transferred to bone phantom materials during hemispherical
reaming by an experienced joint surgeon and speed of the reamer advancement
were measured to develop a robot-assisted acetabular reaming system for
total hip arthroplasty. The surgeon seemed to keep the force constant around
100N during reaming. Based on the data of reaming with a hand-held tool
by the surgeon, robot-assisted force-feedback reaming in the direction
of reamer advancement due to the elasticity of the rigid frame of work.
Keywords: Total Hip Arthroplasty, Robot-Assisted Acetabular Reaming, Navigation
Abstract: We have development an endoscopic robot system that enables various
surgical procedures in the gastric tubes using two manipulators. During
robotic surgery, surgeons often miss targeted 3D loation or the direction
of the endoscope's tip in an abdominal region. Therefore, we have developed
an image guided function for the endoscopic robot system. This function
uses two components:a magnetic 3D location sensor and a graphic work station.The
magnetic 3D location sensor tracks the location and the direction of the
tip of the endoscope. The graphic work station captures the endoscope's
video image and superimposes the patient's organ models onto the image
using measured values of the location sensor. In this paper, we will describe
the system's overview and the result of an animal experiment that we performed
using this system.
Keywords: image guided surgery, data fusion, endoscopic robot
Abstract: Intra-operative navigation in which the target position is provided
to help the intuitive understanding of surgical field has been studied
and applied in each clinical area. Position measurement of surgical field
is usually performed with a magnetic sensor or a marker type optical sensor.
In the navigation of hard tissue such as bone , the measurement of several
markers which are dispersedly located on the surface is enough to detect
the position of the object. However, for the navigation of soft tissue
such as skin and liver , a sensor which can detect the deformation of the
object surface will be required. In this study , a geometrical pattern
generated by a PC projector is captured by DV cameras from multiple angles.
This system can be easily set up in the operation room and can visualize
the 3D deformation and texture of the living body.
Keywords: 3D Deformation Imaging, Registration, Navigation
Abstract: Many types of medical images are used for neurosurgical navigation
system, however, surgeon often encounter the difficulties to have a precise
registration between pre-operative images and the patients. To solve this
problem , we proposed to apply " augmented reality system" with
a simple display device . The display device comprises a 5.6 inch LCD flat
panel display, a half mirror, and a passive positioning maker to detect
the spatial position in the operating room. Through the half mirror, surgeon
can observe the real patient and reflected image of the display, on which
the navigation image are described similtaneously. By this navigation system,
the slice image is shown in appropriate positions and theexact size. In
this paper, we devised the new calibration technique which instantly combines
three dimentional MRI image and natural view space . This device will be
useful using intra-operative images such as interventional MRI.
Keywords: surgical navigation, augmented reality , half mirror
Abstract: We have developed an augmented reality navigation system for
laparoscopic surgery so far. This system measures the 3D position at the
tip of ultrasound probe in abdominal cavity . Although a magnetic tracker
is suitable for this purpose, their accuracy is affected by metallic objects
such as operating equipments and tables. We have recently proposed the
method of precise " real-time" distortion correction of magnetic
fields. In this paper, we evaluated the accuracy and validity of this system
by the in vivo experiment.
Keywords: AR navigation, distortion correction, 3D-US
Abstract: Augmented reality (AR) system for rigid endoscopic surgery have
been widely studied for clinical application . We analyzed superimpose
accuracy incorporating registration, camera calibration, and tracking errors,
which are components of a total AR system. Laparoscopic and arhroscopic
AR systems were analyzed in this study . We investigated the dependency
of the superimpose error on distance from camera coordinate origin to coordinate
origin of rigid body. In case of laparoscope , when distance from camera
coordinate origin to coordinate origin of rigid body is 500 mm , the error
of superimpose was 4.7 pixels. In case of arhroscope, when distance from
camera coordinate origin to coordinate origin of rigid body was 300 mm,
the superimpose error was 3.7 pixels.
Keywords: surgery navigation system, registration error, camera calibration,
accuracy validation.
Abstract: Introduction: Resent dvancement of laparoscopic surgical technology
allowed us to perform advanced high level surgery such as lymph node dissection
for malignancy. Deep understandings of the anatomy would play an important
role to perform a complicated lymph node dissection. We developed a novel
imaging information system for laparoscopic surgery presenting 3D CT angiography
reconstructed as laparoscopic view . We developed a new soft for Windows
OS PC, which provided us real time 3D angiographic image synchronized with
intraoperative endoscopic motion using a motion sensor. In this paper we
described impact of our new laparoscopic virtual reality simulator and
navigation system. Methods: Enhanced multi detector CT rendered by a PC
(OS : Windows XP) can provide us 3D angiography reconstructed laparoscopic
view . This PC connected to the motion sensor, which was mounted on an
endoscope and could detect an angle of direction of laparoscopy, can synchronize
these images to the direction of laparoscopy . A submonitor controlled
by Endo alpha system (Olympus. Co, Japan) projected these images beside
a main monitor. The operator navigated the surgery with reference to this
monitor during lymph node dissection real timely. This system also can
be used as preoperative virtual reality simulation. Result: Our new simple
navigation system will be new weapon for the safety laparoscopic surgery
.
Keywords: computer aided surgery, laparoscopy, navigation surgery
Abstract: Intraoperative MRI is very important modality especially for
glioma resection in neurosurgery, since the tumor status can be evaluated
interactively by updated MR images taken whenever necessary. But it is
difficult to identify only a brain tumor from among unclear border between
brain tumors and normal tissues. Consequently for the purpose of identifying
only a brain tumor by utilizing different elasticity between brain tumors
and normal tissues, we have developed hybrid navigation system using image
fusion of intraoperative MRI and ultrasound elasticity imaging.
Hybrid diagnosis combined morphologic images and elasticity images may
maximize the diagnostic yield compared to the conventional diagnosis using
only a morphologic image.
Keywords: hybirid navigation system, image fusion, intraoperative MRI,
elasticity imaging
Abstract: We have developed an operating system that provides several kinds
of objective information for neurosurgery (intelligent operating theater).
This system mainly detects anatomical, functional, and histological information
obtained by intraoperative MR images/navigation, the mapping/ monitoring,
and frozen setion/5ALA, respectively. The intraoperative information contributed
91% of the resection rate and 13% of the complication rate in infiltrative
glioma cases. To improve the surgical results, we need not only to improve
the quality of each information, but also to integrate the different kinds
of information. We here report the data integration system via the navigation
to help the decision making process in the surgical procedures.
Keywords: glioma, resection, navigation system
Abstract: Final goal of this research is to achieve a perfect extraction
of malignant brain tumor with Open MRI system, while preserving a brain
function. Followings might be major reasons for poor accuracy or extended
surgical time; 1) Technique is difficult to obtain an ideal condition using
present pointer for registration. 2) Training is required to search an
exact position of each marker on the MRI image. Authors developed a reflect
ball marker that can solve the above problems. This newly designed marker
has the combined function of conventional operation marker with function
of reflective ball can be recognized by optical position measuring equipment.
Then, automatic registration become possible to eliminate 1) and 2). Consequently,
navigation preparation time was dramatically decreases, and navigation
accuracy became much improved.
Keywords: registration, Reflective ball marker, Navigation preparation
time , Navigation accuracy
Abstract: Preoperative diffusion tensor imaging obtained by using 1.5T
MRI makes it clear that tumor's position vis-a-vis pyramidal tract in surgical
removal of a malignant brain tumor which is close to the pyramidal tract.
But it can't be used for operating navigation image because brain parenchyma
movesand changes the shape after the tumor has been removed step by step
. Our aim is to develope the navigation system employing updated diffusion
tensor imaging using 0.3 T intraoperative open MRI to complete removal
of a cerebral tumor. Fine adjustment of static magnetic field, conformity
assessment of diffusion tensor imaging of the conventional coil for operations
, study of diffusion tensor imaging parameters with a diagnostic head coil,
diffusion tensor analysis and evaluation were done in the open MRI operating
theater (AIRIS II 0.3 T, Hitachi Medical co.). In consequence, homogeneity
of static magnetic field has improved . Because the conventional coil for
operations did not fit for diffusion tensor imaging, it needs to be improved.
The diffusion tensor imaging for volunteer enabled the white matter fiber
such as pyramidal tract and corpus callosum to be displayed.
Keywords: intraoperative MRI, intraoperative diffusion tensor imaging,
real-time update navigation
Abstract: Real - time MR images are quite useful in image-guided interventional procedures, but they have some limitations. For the fast image acquisition, T1-weighted SPGR images are usually utilized for this purpose. Because of the limited acquisition time of 2-3 seconds, the image quality and contrast are not always satisfactory. Sometimes, T2-weighted contrast and multi-slice acquisition are required for the accurate image navigation in the 3-dimentional space. To slove these problems and to assist real-time MR-guided interventional procedures, we have developed two software applications, MRNavi and ScoutPlane. The MRNavi utilized high-resolution preoperative images in combination with real-time MR images for the navigation in 3-dimensional space. It can control the MR scanner and can change acquisition parameters between needle tracking and MR temperature monitoring. The ScoutPlane can control multislice acquisition interactively while running the MR scanner. It has a capability to acquire, to calculate and to display multi-planar MR temperature maps. These two applications remarkably increased the feasibility of MR -guided interventional procedures.
Keywords: MR-guided intervention, Real-time MR images, interactive image
guidance.
Abstract: Navigation system has been introduced into Otolaryngology for
more than 10 years, during which various kinds of machines have been developed.
It has been accepted by most of the Otolaryngologists because of its usefulness
which has been reported in the literatures. Meanwhile, further efforts
are required to improve the functions for clinical use.
A questionnaire survey was carried out in departments of Otolaryngology
of 202 major hospitals in Japan, which aimed at the indication, the advantages
and disadvantages, troubles occurred in use and corresponding measures
adopted, further, expectation on the navigation system, and in what degree
this system has been applied as an intraoperative guidance as well as in
clinical education. Here we would like to report the results of this questionnaire
survey.Finally, we would like to thank all the Otolaryngologists who have
contributed to this questionnaire survey.
Keywords: Navigation system, Questionnaire Survey, Otolaryngology
Abstract: An in vitro Lithe model replicating individual human cerebral
artery for intravascular neurosurgical simulation, preclinical testing,
and testing of medical devices is presented. This anatomically accurate
arterial model is constructed using individual information obtained by
medical imaging. With its soft membranous structure having some physical
properties close to the value of arterial tissue, realstic surgical simulation
accompanied with deformation of arterial structure is realized . We also
present a composite arterial model reproducing also the surrounding soft
tissues, exiting around the cerebral artery, in addition to the membranous
arterial structure. As the presented arterial model is compatible with
current major imaging modalities such as CT, MRA and TCD , it should prove
useful for a wide range of applications, such as hemodynamic study and
radiological investigations as well as surgical simulations.
Keywords: medical image , vascular model, apid prototype
Abstract: In previous work, we have developed a direct indication device
of the navigation information for a surgical tool position and orientation
by using an intersection line of dual laser beam plane. Although it was
actually applied hip surgeries and showed the effectiveness, it was actuality
that the rearrangement of laser devices was occasionally disturbed the
surgery because of the calibration of the laser device positions. To escape
the intra-operative calibration, we propose a new solution of the calibration-free
laser guidance device which is rigidly equipped with a three-dimensional
(3-D)localizer. In this paper, we theoretically describe the relation between
the geometries of the devices and guidance information indicated on the
side of a surgical tool . The results of available space analysis of the
system are also shown.
Keywords: augmented reality, laser projection, surgical navigation, orientation
guidance, accuracy validation
Abstract: Recent advances of the interventional MRI (surgery in the Open
MRI) proceed more safe and assured minimally invasive surgery using MR
images acquired during operation. To achive more precise, fast and safety
therapy, the introduction of a surgical robot is one solution with the
combination of image information, however, a mere introduction of the conventional
robot is prohibited because it will probably disarrange the strong magnetic
field in MR environment and cause image distortions. In this study, we
are presenting 2DOF small MRI-Compatible surgical robot, which is made
of non-ferromagnetic materials. We also evaluate the manipulator in MR
environment , and conclude that this actuator have enough positioning accuracy
and has almost no influence to the image quality.
Keywords: MRI compatible actuator, surgical robot
Abstract: In order to insert the electrode for microwave ablation into
the tumor accurately , several techniques were utilized . The tumor area
was shown as a colored 3-dimensional volume. Usually repeated punctures
and ablations were required for the complete treatment of the tumor. The
already treated part was indicated by foot-ball shaped " Foot Prints
" and the remaining parts of the tumor to be treated were shown clearly.
Since the effective coagulated area by the microwave ablation is 20 mm
in diameter, 20 mm thick cylinder was displayed depending on the direction
of the puncture route. The direction of the needle was adjusted to include
the target in the cylinder. After careful adjustment of the direction,
the planned lane for the puncture was imprinted to the preoperative 3-dimensional
volume data. From the 3D data including the lane, reformatted images corresponding
to the real -time MR images were constructed . It had been difficult to
detect the displacement of the needle during puncture in the real-time
images controlled by the needle position. Using these techniques, accurate
navigation could be carried out by simple tracking of the lane in the reformatted
images and effective microwave ablation of liver tumors was accomplished.
Keywords: Cojputer-aided MR guided ablation and Lane guide navigation
Abstract: [Objective] Minimally invasive surgery requires variety of imaging
modalities, including endoscope and CT/MRI . In most cases these images
are presented as 2D in separated views. This study proposes real-time integration
and rendering method for intraoperative medical images. ［Methods] Three
types of medical images, volume data, optical images (ex. endoscope ) and
instrument data are subject to integration, and each image needs different
rendering methods . VGL graphics library has capability of volume rendering
mixed with OpenGL geometry. DirectShow class library supports capturing
of optical video images. ［Results] The graphics performance was sufficient
for intraoperative use (15.2 fps) on a PC (Xeon 2.8 GHz) with CT (256x256x101
voxels), endoscope and instrument data. A delay was slightly observed in
endoscopic view, though . [Conclusion］VGL and DirectShow realized three-
dimensional integration and real-time rendering of volume data, optical
images and instrument data on standard PCs.
Keywords: image integration, volume rendering, VGL, DirectShow
Abstract: The data fusion system is a surgical navigation system, which
enables surgeons to observe the inner body structure during surgery.
We have been developing several techniques or algorisms which are essential
for the data fusion system. In this study, we focused on image display
devices of the data fusion system specific for open surgery . We have developed
two types of display devices which use two different types of mixed reality
technique: a video see-through method and a floating window method. Our
devices consist of a liquid-crystal - monitor attached to the ceiling -mounted
articulating arm and a 3D optical tracking system.The monitor and the objective
organ were registered by the optical tracking system, and the 3D inner
body structure model reconstructed from CT or MRI images was displayed
on the monitor during surgery. As for the floating window method, the head
position of the surgeon was also registered preceding surgery and tracked
by the optical sensor, so that the surgeon could observe from various points
of view.In contrast, the video see-through method uses a small size video
camera mounted on the back of the monitor in order to take the image from
the same viewpoint as viewed by a surgeon. We validated the performance
of these two devices by an experiment in the operating room.
Keywords: data fusion system, optical see-through, video see-through
Abstract: Correction or control of spinal alignment is one of the reasons for use of spinal instrumentation. However, there is no metod to visualize and track the three-dimensional (3-D) alignment of the operated spine segment during surgery. CT-based image guided surgery has enabled us to track and visualize the present 3-D position of the vertebra and surgical tools . In the most CT-based navigation systems, the vertebral motion is tracked by the dynamic reference frame, which was attached to the spinous process of the target vertebra. Therefore , using the dynamic reference frame as a motion tracker allows us to track the 3-D alignment of the operated vertebrae as well as the surgical tools under the guidance of computer navigation. In order to evaluate the 3-D alignment of spine segment, we have developed a novel intraoperative measurement system by using a CT-based navigation system for spinal instrumentation system. In each case, 3-D alignment of the operated spine segment was measured . This system allows us to monitor the alignment of fused segments and can be an effective and feasible tool for spinal fusion surgery.
Keywords: Spinal instrumentation, Navigation , Intraoperative measurement
and Reporting system
Abstract: In neurosurgery, tumor tissue most be removed as much as possible
to prevent recurrence. We have studied on application of 5-Aminolevulinic
Acid (5-ALA) as a tumor marker. 5-ALA biosynthetically induces a fluorescent
substance called Protoporphyrin9 (Pp9).Pp9 is excited by blue or violet
light and emits red fluorescence. Detection of the fluorescence can lead
to precise removal of tumor. We introduced a blue-violet laser diode as
an excitation light source and an optical fiber to collect the fluorescence.
We aim to detect the fluorescence with high spatial resolution for better
resection rate. To achive this purpose, we focused the laser on the surface
of brain tissue to limit the area to generate fluorescence. In this paper,
we made an optical phantom for brain tumor taking scattering coefficient
into account. And also, we studied on the effect of focusing laser beam
changing laser spot diameter. Our result shows that broadening of illuminated
area will increase the intensity of collected fluorescence. On the other
hand , it may impair the spatial resolution. In addition, our new optical
phantom is highly useful for 5-ALA study, especially for experiments for
demarcation of tumor boder.
Keywords: Neurosurgery, 5-ALA, 5-Aminolevulinic Acid, Protoporphyrin9,
Point Measurement, Optical Phantom
Abstract: During cryotherapy, it is extremely useful for the interventionalist
to have available intra-operatively a 3D iceball visualization in order
to ensure the effectiveness and safety of the procedure. Additionally,
it highly beneficial to provide the interventionalist with a best estimate
of what will occur in near future so the progress of the procedure can
be carefully controlled. That is, the aim is to provide a best estimate
of how the iceball will grow and an estimate of the extent to which the
target region and the tissues around it will be ablated .The quantitative
analysis of ablation treatment is difficult during therapy due to the typically
2D representation of intro-operative MR image information, and the inhomogeneity
of the iceball growth due to nearby vessels or other perturbing anatomy.
Previously, we formally developed and evaluated a predictive method for
estimating the extent and effectiveness of thermal therapies using 2D optical
flow. In this study, we introduce a newly developed computerized control
system for cryotherapy using 3D visualization and a 3D optical flow computation
along with other novel software tools . Our new control system provides
intra-operatively for the real-time and future-predicted quantitative assessments
of the cryotherapy treatment. System evaluation and validation was performed
using animal cryotherapy experiments data.
Keywords: MR-guided Therapy, Cryotherapy, Optical Flow, Segmentation
Abstract: CT images in the oral area are often disturbed by artifacts due
to metallic dental prostheses, and valuable information on dental treatment,
such as dentition, occlusion and maxillomandibular relation is often damaged
. This study attempts to substitute the damaged dentition area of the cranial
bone image with a dental cast model image obtained by CT . The position
of the dental cast image was registrated to that of the cranial bone image
using a devised interface that was composed of an occlusal bite and a marker
plate made of gypsum.The damaged region in the cranial bone image was removed
and substituted with the trimmed image of the dental cast. In the developed
method, the image of dentition severely damaged by an artifact was successfully
restored, and the image of stomatognathic system became clear.
Keywords: artifact, 3-D CT image, computer, dentistry
Abstract: Hydroxyapatite Implant for cranioplasty is designed by using
computer-aided design and computer-aided machinery (CAD/CAM) technique
based on CT data to prepare an accurately shaped implant . Recently , the
perforamnce of CT scanner was remarkably advanced and put into practical
use, permits higher image processing speed, however, patients were exposed
to radiation. Therefore, We tried to design hydroxyapatite ceramic implant
based on data from MRI .
Keywords: MRI, CT, hydroxyapatite, cranioplasty
Abstract: Magnetic resonance imaging (MRI) is known to be the only modality
for non-invasive imaging of internal organ temperature under thermal therapics.
The thermal change in the phase evolution of the macroscopic magnetization
vector has been obtained as the temperature indicator in the conventional
method by subtracting the phase at each voxel before heating from that
after heating. In the moving organ such as liver , however, the voxel-by-voxel
phase subtraction process becomes problematic because of the change in
the tissue position and the magnetic flux.To overcome this problem, we
have proposed a " self-referenced " method, in which the reference
phase value without thermal change is estimated based on the spatial continuity
of the phase distribution around the treated tissue region. Our preliminary
experimental results demonstrated that the method is effective and viable
for imaging liver temperature in vivo. The preprocessing for the compensation
of phase wrapping was effective when such phase wrapping was inside the
phase field to be used for the phase estimation.
Keywords: MRI, temperature, phase, motion, self-referenced
Abstract: Magnetic resonance imaging (MRI) has capability of imaging temperature
change during thermal therapies. To date , the conventional way, in which
temperature change distribution is obtained by taking the voxel-by-voxel
phase difference of water proton system at different temperature states,
has been used. In imaging temperature distribution in an abdominal organ
such as liver, the subtraction process suffers remarkable effect of respiratory
motion. A new temperature imaging method called " self-referenced
" method, in which temperature difference is obtained by estimating
the fase distribution before temperature change based on the smoothness
and continuity of the phase field around the heated region, was proposed.
Two different strategies of the phase interpolation were compared. The
approach to estimated the phase distribution using the real and imaginary
part distributions around the region of interest was superior to the approach
using the phase image directry: the error in the former was around 5℃and
was , at most , 10% of that in the letter even when the conventional method
completely lost the temperature information due to the significant effect
of the organ motion.
Keywords: MRI, temperature imaging, phase subtraction, interpolation, error
Masaki Takao a, Nobuhiko Sugano a, Takashi Nisii a, Hidenobu Miki a, Tsuyoshi
Koyama b, Yoshinobu Sato c, Shinichi Tamura c, Hideki Yoshikawa a, Takahiro
Ochi b
a.Department of Orthopedic Surgery, Osaka University Graduate School of
Medicine, Osaka , Japan
b.Division of Robotic Therapy, Oska University Graduate School of Medicine,
Osaka, Japan
c.Division of Interdisciplinary Image Analysis , Department of Medical
Robotics and Image Sciences, Osaka University Graduate School of Medicine,
Osaka, Japan
Abstract: Image registration is a comp utational process for matching 2
different images. To apply this method for longitudinal evaluation of lesions
around knee joints, we investigated the accuracy of three-dimentional (3D)
MR volume registration for both distal femur and proximal tibia and fibula.
Five phantoms of the knee joint were made from embalmed cadaveric knee
joints. Each phantom was MR imaged in 9 positions, with 8 markers attached
to the distal femur and the proximal tibia. Eight MR images were registered
to the remaining reference image , resulting in total 40 sets of registration.
The accuracy of registration was evaluated by measuring the 3D displacement
of the markers of the distal femur and proximal tibia were 0.44 ±0.14
mm (SD) and 0.63 ±0.36 mm(SD), respectively . These were smaller than
the voxel size (1.32x 1.32x1.5mm). The translation error was also less
than the voxel size, and the rotation error was less than 1°. This method
is apparently useful for precise evaluation of lesion size change around
knee joints.
Keywords: magnetic resonance imaging; image registration; knee joint
Abstract: We developed a CT-based program to demonstrate the locus of the
dynamic loading axis on the proximal tibia joint surface during gait using
CT images. We added an option to reconstruct patient specific bone models
of the lower limbs using MR images instead of CT images. Purpose of this
study is to demonstrate how the option wouks. MR images of whole lower
limb were taken with ball markers of gait analysis. Walking data of healty
volunteer was obtained using Vicon motion analysis system. The MR sequence
was 3D Fast SPGR , TE In phase (4.2msec), TR9.0msec, Flip angle 15deg,
Band width 31.25 kHz, FOV 42cm , Thickness 2mm, Location per slab 64, Matrix
256*256, 1NEX , 1min 27sec/slab. MR images of whole lower limb were obtained
by connecting the seven parts of the lower limb in 3D . The 3D surface
models of the femur, tibia, and ball markers were reconstructed from axial
MR images. The ball marker positions between MR images and gait analysis
were matched . The relative positions of the femur and tibia during gait
were calculated. The locus of the dynamic loading axis that the loading
axis of the lower limb moved along the proximal tibia joint surface during
gait was showed .
Keywords: locus of the dynamic loading axis on the knee, MRI based simulation
system
Abstract: The purpose of this study was to assess the accuracy of gait
analysis system for assessment of Dynamic Loading axis of the Knee. This
system uses force plate data, CT skeletal structure data and motion capture
data ( obtained using an infrared position sensor). The relative positions
between bones and markers were used to calculate skeletal model movement
based on movement of the markers. The locus of the dynamic loading axis
on the knee joint was defined as the line that the loading axis of the
lower limb moved along the proximal tibia joint surface.
To assess the accuracy of this system, open MRI was used to evaluate positions
of skin markers against bones in 6 healty volunteers. The mean value of
measurement error for opint locations on the locus was within 2.3±1.4(mean±SD)%
of medial compartment joint width of the knee joint in the lateral direction,
and within 19±9.7 % of the anterior half of anteroposterior joint width
in the anteroposterior direction. This system can provide clinically useful
information for evaluation of the dynamic loading axis on the knee joint
surface.
Keywords: locus of the dynamic loading axis of the knee, accuracy of gait
analysis system , open MRI
Abstract: This paper shows the results of performance comparison of two
similarity measures, mean squared error (MSE) and normalized mutual information(NMI)
, for bronchoscope tracking based on image registration between real and
virtual bronchoscopic images.
Video tracking performance of MSE and NMI were examined for five cases
of bronchoscopic video frames and chest X-ray CT images . The experimental
results indicated that NMI was more sensitive than MSE to the difference
of lighting conditions between real and virtual bronchoscopic images and
the reproducibility of bronchial folds in CT images. Consequently, MSE
was better than NMI in average accuracy of bronchoscope tracking and computation
time.
Keywords: endoscope navigation system, mean squared error, normalized mutual
information
Abstract: This paper describes a preliminary study on estimation of the
region of alveolar bone resorption and automated measurement of its depth
. Measurement of the depth of bone resorption is an important index of
the extent of periodontitis. Although it is physically measured by inserting
a probe, the insertion is difficult on the interproximal sides. The resorption
is also examined by using dental X-ray images. In this case, the depth
is measured as the distance between cement-enamel junction (CEJ) and the
bottom of the resorption. The X-ray examination has the advantage of being
able to measure the depth even on the inter- proximal sides. However, there
is no report on automated resorption depth measurement using dental 3-D
X-ray CT images. Our methods use dental CT images to estimate the bone
resorption region and automatically measure the resorption depth around
the tooth of interest. The experimental results showed that the proposed
methods could be used to extract alveolar bone resorption and measure its
depth.
Keywords: bone resorption, automated measurement, 3-D dental CT
Abstract: In order to clarify the design strategy of an epidural anesthesia
needle, measurement of resistance force during epidural puncture and development
of a simulator are essential . At first , authors conducted an animal experiment
to measure the resistance force. A male pig (weight 40 kg) was employed
.One surgeon as professinal and three amateurs did the epidural anesthesia
using a handy-type force sensor attached a clinical needle (17G). Data
showed the difference between the professional and amateurs. Force waveform
of the professional subject had only one peak, whereas that of the amateur
subjects showed several peaks. Times from inserting the needle till getting
out were ten seconds for the professional , thirty seconds for the amateurs.
Keywords: Epidural anesthesia, Resistance force, Needle , Puncture
Abstract: This paper proposes a method for heartbeat measurement using
a micro acceleration sensor. It succeeded in taking the acceleration and
the force of the heat pulse of an animal . It newly experimented using
a sensor with a very sufficient system called an electrostatic capacitance
type acceleration sensor, and drawn-in type stabilizer type measurement
equipment was developed . We plan to develop the operation robot based
on this data.
Keywords: micro acceleration sensor, cardiac surgery, minimally invasive
surgery
Abstract: For cardiac plastic surgery, pressure-volume graph (P-V loop)
is used to evaluate the heart function of a patient. We have developed
the cardiac muscle palpation system, and it have been appreciated from
the cardiac surgeons. Recently, volume reduction test using a heart lung
machine is applied to the patient heart in the operating room for improving
the surgical efficiency, where the cardiac surgeons can estimate the efficient
volumic range for pumping ability of heart. To add an evaluation tool of
the cardiac function into our system have been required from the cardiac
surgeons. In order to build the cardiac functional evaluation tool, F.E.M.
analysis is used for a simple heart model during one cardiac cycle . This
paper presents how to identify the young modules of the left ventricular
muscle changing during a cardiac cycle by using P-V loop by a living dog,
and shows the simulation results . As future work , we are going to make
the virtual heart model from the patient's heart images and to apply the
presente methods on it.
Keywords: F.E.M. analysis, Heart function, Virgual heart, and Volume reduction
test.
Abstract: Adaptation of surgical navaigation to organ deformation is desired
for theimprovement of the system in terms of its accuracy and functionality
. In this study, as a means to obtain real-time quantitative data of intraoperative
organ deformation, we appended mobility to a 3-D digitizer with keeping
the 3-D shape representation in the unique coordinate system in an operation
room . Optical markers were attached on the 3-D digitizer, and its motion
was tracked by a 3-D localizer. The 3-D shape data obtained by the 3-D
digitizer was represented in the optical marker coordinate system using
a calibrated transformation matrix, and then it was represented in the
3-D localizer coordinate system according to the position tracking of the
optical markers. The accuracy of each device was under 0.4 mm in mean value
, but the accuracy of the whole system was up to 2.5 mm in mean value.
The speed of contimuous data acquisition was 1.8 sec/frame in the low resolution
mode, this was considered to be enough for surgical navigation.
Keywords: surgical navigation, organ deformation, 3-D digitizer, 3-D localizer
Abstract: In order to perform the operations safely, it is essential to
have a clear grasp of the three-dimensional (3D) relationship between the
target and inner structures. However, abdominal organs such as the liver
deform considerably during the operation. It is difficult for surgeons
to imagine the inner structures of the organs spatially with preoperative
data. Our aim is to develop a data fusion system for liver surgery which
assists surgeons to intuitively visualize the inner structures of organs.
To realize the system , we use preoperative image data and intraoperative
surface movement data captured by cameras from multiple directions. A 3D
model was reconstructed with preoperative data to preserve the structual
organ information. As well , surface movement data was acquired by using
color information from cameras and the preoperative model was mapped onto
the intraoperative surface data. Intraoperative inner structures of the
organs were provied to modify the preoperative 3D model with the surface
movement data. In this paper , we present and evaluate the feasibility
of measurement with a stereo camera in the intraoperative environment through
an animal experiment.
Keywords: data fusion, open surgery, deformable model , stereopsis
Abstract: We have been developing a virtual surgery system that can simulate
surgical maneuvers on elastic organs with haptic feedback. In order to
simulate such surgical technique in real time, we have constructed an elastic
organ model called a sphere-filled model that is suited for real time and
quantitative deformation. In this research, our purpose is to make various
incision planes according to surgical techniques in real time by using
volume data. In order to deform the volumetric model , we adopted the rhombic
dodecahedron as the formation of the voxel group assigned to the sphere
and the formation that follows the motion of each sphere. Moreover, we
could monitor the deformation of the surface and the inner structures by
superimposing the surface model onto the volumetric model. By using this
method and modifying this model, we could make a deeper incision in the
same region and a slanting incision that approached the resection for volume
data without losing current imaging speed . Consequently , we were able
to perform not only pushing and pinching but various incisions that approached
the resection in this system.
Keywords: virtual surgery system, volume data, incision
Abstract: We have been developing a virtual surgery system which uses a
sphere-filled model on elastic organs, Furthermore, we have conncted a
dual force feedback device to this organ model to provide the user with
force feedback , specifically the sensations of touch and force. In such
a surgical simulator, it is important for the system to apply the realistic
organ deformation and realistic haptic feedback . In this study, to apply
the quantitative haptic feedback to the system , we measured the relationship
between the surface deformation value of the soft tissue and the pressure
that is shown by the compress device in in-vivo experiments. Also, we made
a database based on the measurements, and adapted the database for our
surgical simulation system. As a result, this system allows the user to
simulate the surgical maneuvers with a soft tissue model which not only
performs the real time deformation but also has the property of quantitative
haptic response.
Keywords: sorf-tissue model, haptic response, surgical simulation, in-vivo
experiment
Abstract: This paper presents a high- quality glass -less autostereoscopic
display system that is itegrantd into image-guided surgery. The glass-less
autostereoscopic image was created by employing a modification of Integral
Videography (IV) , which is an animated extension of Integral Photography.
IV records and reproduces 3-D images using a micro convex lens array and
plat display , which can display geometrically accurate 3-D autostereoscopic
images and reproduce motion parallax without any need for special viewing
devices. This paper reports the use of high -resolution IV display and
high performance computing for producing medical 3-D image. We evaluate
the feasibility of this display by using a set of medical image with segmentation
and reproducing 3-D CT and MRI autostereoscopic image for surgical planning
and intra-operative guidance. The main contribution of this paper is application
and modification of medical 3-D display technique originally developed
in high-resolution autostereoscopic display and high performance computing.
Keywords: integral videography, integral photography, autosteroscopic,
3-D image processing
Abstract: The stereoscopic pictures obtained from Magnetic Resonance Image(MRI)
etc. are used for an diagnostic and operation-supporting picture. One of
the stereoscoic methods is integral videography (IV) , we have developed
based on integral photography, projecting a computer-generated graphical
object. Furthermore using parallel processing method integrating Message
Passing Inteerface (MRI)on High Performance Computer (HPC), we shortened
the calculating time of IV picture by the shortest at about 0.1 seconds.
Now, by using socket communication it transmitted to another portable note
PC, which is for a display, and we used 3D -Slicer for the controller of
IV image and displaying tomograms. Then, we achieved the fast presentation
of tomograms and stereoscopic pictures seen from arbitrary direction that
was specified with the 3D - Slicer at anywhere we can access to the network.
Keywords: MPI, Integral Photography, Integral Videography, parallel Rendering,
3D-Slicer
Abstract: This paper presents an intraoperative segmentation of brain tumors
for open MRI guided surgery. The intraoperative segmentation can show the
tumor margin and the representative measurement of tumor size during the
surgery. Fuzzy Connectedness (FC) method was used , which has a strong
robustness to image noises. The method was validated in five patients aged
32-66 years with gliomas. FC segmentation was performed on axial T2-weighted
image, where brain tumors have high intensity. Each MR data was segmented
manually by a neurosurgeon and was employed as true segmentation. Then
Correspondence Ratio (CR) and Percent Match (PM) , which are equal to 1
when perfectly matched , were caluculated between manual and automatic
segmentation results. The accuracy results showed that average CR and PM
were 0.75 and 0.81 respectively, which are sufficient considering the signal
-to-noise ratio and voxel resolution of Open MRI. The validation in the
tumor resection rate was also performed and the results showed the presented
segmentation can estimate the tumor resection rate precisely in 92% . It
cah be concluded that the presented segmentation can precisely track the
size of brain tumor as it responds to treatment during Open MRI guided
surgery.
Keywords: Brain tumor, sdgmentation, intraoperative
Abstract: We have been developing a 4-dimensional motion analysis system
for patients having had total hip arthroplasty (THA) . This system aims
to simulate the patient's skeletal movement and estimates the complications
after THA. However, the causes of the complications such as dislocation
are influenced not only by the movement of the skelton but also by the
muscle force induced by the surrounding muscles. Therefore, we added the
4-dimensional muscle model to the skeltal model. In order to estimate the
direction of the muscle force and the length of the muscles , we have developed
a string - typed muscle model which represents the route of the muscles.
The strings expand and contact according to the movement of an origin and
an insertion of the muscle . We developed models of the five muscles related
to the movement of the hip joint . To estimate the precise route of the
muscles during hip motion, we calculated the interference between bones
and muscles , so that the muscle moves on the bone surface . By using this
model , clinicans can predict the potential for dislocation or recognize
the causes of dislocation, including the influence of the muscles .
Keywords: 4D muscle model, total hip arthorplasty (THA) , dislocation
Abstract: In the medical field, the 4-dimensional human body model combined reconstructed 3-dimensional image data (CT and MRI)and exercise data of human body was gradually applied in some clinical cases. We applied this technique to the mandibular movement analysis in the dentistry domain, and develop the 4-dimensional analyzing system for mandibular movement.The aim of this sutdy was to inspect the precision of this analyzing system. A dry skull was used in this study, and the mandible was fixed by each mandibular position to the skill . The skull-mandibule relationship of each position was measured by two procedure. At first, a CT measurement was performed and the 3-dimensional image was reconstructed and the true values were established. Secondly, the optical measurement equipment marker with the dental arch was made into positional measurement values. Then, the measurement values were contrasted with the corresponding true values to inspect measurement errors between them.As a result, it became clear that the RMS errors of the 4-dimensional analyzing system of mandibular movement was at an average of ±0.405mm and ±0.431 degree. This shows that this analyzing system has sufficient measurement accuracy for functional examination of temporomandibular disorders.
Keywords: 4-dimensional analysis of mandibular movement , precison, 3 dimensions
of reconstitution images
Abstract: Purpose: The aim of this study was to analyze the mandibular
movement of a patient with square mandible using the 4-dimensional (4D)
analyzing system, and to suppose the cause of square mandible from charasteristics
of the movements. Method: Subjects were a healty volunteer and a patient
with square mandible. A volunteer was a 26-year old female who had no missing
teeth and no morbid findings in clinical examination. A patient was a 37-year
old female.Diagnostic imaging scarcely depicted any disc derangement, but
a severely limited jaw opening was noted . As well , her facial appearance
showed a characteristic square mandible facial configuration. The skull
and mandible were reconstructed into a 3-dimensional (3D) bone model from
the CT data and mandibular movements were recorded by a measurement device
of MM-JI-E (Shofu Inc.). The bone model and the mandibular movements were
combined using the 4D analyzing system. The origin and halt of each masticatory
muscle were positioned on the surface of the 3D bone model , and connected
together with a string respectively. In this system , the color of the
string was designed to be passively canged in accordance with mandibular
movements. Results and Discussion: In this case, the cause of opening linitation
was not the opening muscle itself but contraction of the temporal muscle.
Therefore, it was supposed that the load extended to the masseter muscle
from the temporal muscle depended on the masseter muscle, and resulted
in muscle hypertrophy or angle hyperplasia.
Keywords: Four-dimensional analysis, Mandibular movement, Masticatory muscle
model, Sqare Mandible.