PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Soft Computing”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,099 records · Page 61Linked to original sources
PubMed2006

Experimental study of multi-slice spiral CT perfusion imaging in VX2 soft-tissue tumor of rabbits.

An experimental animal model of malignant soft-tissue tumor was established to investigate the applied value of multi-slice spiral CT perfusion imaging preliminarily. Ten New Zealand white rabbits which were implanted with VX2 tumor in either proximal thigh were subjected to CT plain scan and perfusion scan two weeks later respectively, then the original perfusion images were transmitted to AW4.0 Workstation. The functional maps and perfusion parameters including blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface (PS) were computed and analyzed. All the values of BF, BV and PS in VX2 soft-tissue tumors were obviously higher while the MTT-values were lower than those in the normal muscular tissues significantly. It was suggested that multi-slice spiral CT perfusion imaging is an accurate, convenient and relatively safe functional imaging technique, and can give a quantitative assessment to angiogenesis and blood perfusion of soft-tissue tumors.

Animals↗
PubMed1987

Application of cine computed tomography to the assessment of velopharyngeal form and function.

The mechanism of velopharyngeal closure is clearly three-dimensional in nature. Numerous attempts have been made to obtain a comprehensive picture of velopharyngeal movement, with varying degrees of success. A computed tomography scan system has recently been developed that may be used for real-time motion study of various body systems. This preliminary study was designed to assess the applicability of multi-level cine computed tomography scanning as a tool in the three-dimensional analysis of the velopharynx. One normal speaker and one speaker with an unrepaired palatal cleft were asked to phonate while serial sections were taken at 650-millisecond intervals through a number of transverse sections in the velopharyngeal region. This paper includes an explanation of cine CT technology, examples of scans on two speakers with clearly different velopharyngeal mechanisms, and discussion of the potential use of cine computed tomography as a tool in the analysis of both normal and disordered velopharyngeal function.

Cineradiography↗
PubMedDate not supplied

Effect of recirculation of 99mTc-Sn colloid in estimating mean transit time of soft-tissue vascular anomalies by direct puncture scintigraphy: a simulation analysis.

We have reported direct puncture scintigraphy, a novel method to estimate mean transit time (MTT) of soft-tissue vascular anomaly. In the examination, 99mTc-Sn colloid is infused percutaneously into the lesion, and MTT is calculated using the time-activity curve for the lesion. Recirculation of 99mTc-Sn colloid is neglected in computing MTT, and this may cause error. The aim of this study was to assess this error by simulation analysis. Data simulating direct puncture scintigraphy were produced for lesions with various blood volumes and various blood flows, considering recirculation and blood clearance of 99mTc-Sn colloid, and MTT was estimated by the same method used in the patient examination. Although MTT was overestimated in large lesions with intermediate or long MTT, the error was small except in extremely large lesions. It was suggested that recirculation of 99mTc-Sn colloid does not cause a serious problem in the clinical use of direct puncture scintigraphy.

Arteriovenous Malformations↗
PubMed2000

The reality of picture archiving and communication systems (PACS): a survey.

Toward the end of 1997 vendors were succeeding in installing picture, archiving and communication systems (PACS) in larger numbers. It was hard to separate fact from fiction at times. This survey was undertaken by 2 members of the academic community to confirm what was operational, how well the installed systems worked, and what they were doing. Fax questionnaires were sent to nearly 1,000 facilities worldwide to identify PACS of any size in clinical operation on a date certain, February 1, 1998. A total of 177 PACS were identified. Facilities furnished responses during the first survey period from May 1 to November 1, 1998. A second survey, done in February and March of 2000, sought long-term follow-up data. Many systems operated 5 or more types of modalities. Computed tomography (CT) was the most common modality type at 83%, but the distribution of the rest held surprises. There also was an unexpectedly large use of soft copy reading and filmless operation in 1998. Clear trends toward increased use of computed radiography and digital radiography and a significant expansion on the percentage of all of a facility's examinations on the PACS were seen over the 2 years. Satisfaction with original PACS vendors was relatively high. Eighty-nine percent remained with their original vendor. Only 10 sites reported they changed vendors, and 4 facilities said they abandoned their system. The users reported their expectations of the PACS had been met in 81% of cases. Some (65%) declared their systems were cost effective. The most striking response was that 97% of the users would recommend PACS to others.

Asia↗
PubMed1994

Digital image processing. II. In vitro quantitative evaluation of soft and hard peri-implant tissue changes.

The aim of this study was to evaluate the ability of computer-assisted densitometric image analysis (CADIA) to detect small changes in mineralized and nonmineralized tissues adjacent to dental implants and to correlate these changes with CADIA values. A section of a pig mandible including all soft tissues and in which a hollow cylinder ITI Bonefit implant with an artificial mesial and a buccal infrabony defect was placed was used to obtain pairs of standardized radiographs. Series of radiographs were obtained with exposure times of 0.13, 0.20, 0.44, and 0.53 s. Specimens of mineralized or nonmineralized tissues were placed arbitrarily in the defects before each radiographic exposure. The radiographs were captured through a video camera, digitized and stored in a personal computer. Every radiographic image was then subtracted from a baseline one without any change. The result of the subtraction was evaluated with CADIA. A linear correlation (r2 = 0.99) was found between the bone chips (1-5 mg of dry weight) placed in the mesial defect and the CADIA values. Bone chips in the buccal defect (behind the implant), however, were not detected unless their weight reached 14 mg or more. For conventionally exposed radiographs, it was not possible to recognize soft tissue specimens (1-6 mg), either in the buccal or the mesial defect. However, when "underexposed" radiographs (exposure time: 0.13 s) were obtained, a linear correlation (r2 = 0.80) was calculated for soft tissue specimens in the mesial defect and CADIA values. In normally exposed radiographs, the CADIA system could detect even the smallest change in bone density (bone chip of 1 mg of dry bone weight) and correlated almost linearly with these changes. Provided that the radiographic images are obtained with standardized geometry and normal exposure time, the tissue density changes detected by this system within bone defects represent only mineralized tissue changes. By underexposing radiographs, CADIA may even reveal soft tissue changes around dental implants.

Absorptiometry, Photon↗
PubMedDate not supplied

Towards MRI guided surgical manipulator.

BACKGROUND: The advantages of surgical robots and manipulators are well recognized in the clinical and technical community. Precision, accuracy and the potential for telesurgery are the prime motivations in applying advanced robot technology in surgery. In this paper critical interactions between Magnetic Resonance Imaging equipment and mechatronic devices are discussed and a novel Magnetic Resonance compatible surgical robot is described. MATERIAL AND METHODS: Experimental results of the effects from several passive (metallic materials) and active (ultrasound motors) mechanical elements are demonstrated. The design principles for Magnetic Resonance compatible robots are established and the compatibility of the proposed robot is assessed by comparing images taken with and without the robot's presence within Signa SP/I GE Medical Systems scanner. RESULTS: The results showed that, in principle, it is possible to construct precision mechatronic devices intended to operate inside MR scanner. Use of such a device will not cause image shift or significant degradation of signal-to-noise-ratio. An MR compatible surgical assist robot was designed and constructed. The robot is not affected by the presence of strong magnetic fields and is able to manoeuvre during imaging without compromising the quality of images. A novel image-guided robot control scheme was proposed. As a part of the control scheme, biomechanics-based organ deformation model was constructed and validated by in-vivo experiment. It has been recognised that for robust control of an image guided surgical robot the precise knowledge of the mechanical properties of soft organs operated on must be known. As an illustration, results in mathematical modelling and computer simulation of brain deformation are given. CONCLUSION: The novel MR compatible robot was designed to position and direct an axisymmetric tool, such as a laser pointer or a biopsy catheter. New Robot control system based on the prediction of soft organ deformation was proposed.

Animals↗
PubMed1995

A method for histomorphometric characterization of a peri-implantar new formed tissue to biomaterials.

The spatial distribution and concentration of distinct cellular elements are of interest in the evaluation of the biological reaction to implant materials, the so called biomaterials. We present a method, based on a computer assisted cell-counting program, developed to quantify the soft tissue reaction to implanted material. Five pseudomembranes formed around silicone skin expanders were studied; they were subjected to histological immunohistochemical and histomorphometrical investigation. This quantitative approach overcomes weakness due to the subjectivity of the observers and offers new possibilities when assaying the local tissue compatibility; moreover, it shows a good applicability to a wide variety of implant materials.

Adult↗
PubMed1998

Urografin injection demonstrated soft tissue ganglion communication with an intraosseous ganglion cyst.

Intraosseous ganglion cysts rarely occur in the hand or wrist. We present a case of a soft tissue ganglion cyst that communicated with the intraosseous ganglion of the scaphoid. Typical diagnostic studies include radiography, computed tomography, and magnetic resonance imaging. The diagnosis was made in this case by injection of Urografin into the soft tissue ganglion. The patient underwent excision of both ganglion cysts, resulting in a satisfactory outcome.

Adult↗
PubMed2004

Residues determining the binding specificity of uncompetitive inhibitors to tissue-nonspecific alkaline phosphatase.

UNLABELLED: Recent data have pointed to TNALP as a therapeutic target for soft-tissue ossification abnormalities. Here, we used mutagenesis, kinetic analysis, and computer modeling to identify the residues important for the binding of known ALP inhibitors to the TNALP active site. These data will enable drug design efforts aimed at developing improved specific TNALP inhibitors for therapeutic use. INTRODUCTION: We have shown previously that the genetic ablation of tissue-nonspecific alkaline phosphatase (TNALP) function leads to amelioration of soft-tissue ossification in mouse models of osteoarthritis and ankylosis (i.e., Enpp1-/- and ank/ank mutant mice). We surmise that the pharmacologic inhibition of TNALP activity represents a viable therapeutic approach for these diseases. As a first step toward developing suitable TNALP therapeutics, we have now clarified the residues involved in binding well-known uncompetitive inhibitors to the TNALP active site. MATERIALS AND METHODS: We compared the modeled 3D structure of TNALP with the 3D structure of human placental alkaline phosphatase (PLALP) and identified the residues that differ between these isozymes within a 12 A radius of the active site, because these isozymes differ significantly in inhibitor specificity. We then used site-directed mutagenesis to substitute TNALP residues to their respective homolog in PLALP. In addition, we mutagenized most of these residues in TNALP to Ala and the corresponding residues in PLALP to their TNALP homolog. All mutants were characterized for their sensitivity toward the uncompetitive inhibitors l-homoarginine (L-hArg), levamisole, theophylline, and l-phenylalanine. RESULTS AND CONCLUSIONS: We found that the identity of residue 108 in TNALP largely determines the specificity of inhibition by L-hArg. The conserved Tyr-371 is also necessary for binding of L-hArg. In contrast, the binding of levamisole to TNALP is mostly dependent on His-434 and Tyr-371, but not on residues 108 or 109. The main determinant of sensitivity to theophylline is His-434. Thus, we have clarified the location of the binding sites for all three TNALP inhibitors, and we have also been able to exchange inhibitor specificities between TNALP and PLALP. These data will enable drug design efforts aimed at developing improved, selective, and drug-like TNALP inhibitors for therapeutic use.

Alkaline Phosphatase↗
PubMed1999

Immunohistochemical examination of an orbital alveolar soft part sarcoma.

BACKGROUND: A 32 year-old male patient had a 6-week history of left-sided proptosis. Computer tomography revealed a 16x15x15 mm smooth and well-defined mass between the optic nerve and the medial and superior rectus muscles in the left orbit. METHODS: The tumour was excised via a cranio-medial orbitotomy approach. RESULTS: Histopathological examination, immunohistochemistry and electron microscopy findings were consistent with an alveolar soft part sarcoma. Immunohistochemical staining showed positive immunoreactivity for neuronespecific enolase, vimentin, p53 (30%), p21 (10%) and cyclin D1 (20%), and negative immunoreactivity for CD45, cytokeratins, S-100 protein, glial fibrillary acidic protein, synaptophysin, chromogranin, calcitonin, serotonin, thyreoglobulin, desmin, myosin, actin, HMB-45, pRB, p16 and BCL-2. The growth fraction of the tumour cells was 3%. At examination 4 years after surgical excision, there was no evidence of local recurrence or for metastases. CONCLUSION: Alveolar soft part sarcoma of the orbit is a rare malignant tumour best controlled by surgery. The unpredictable behaviour of these neoplasms, however, indicates the need for long-term follow-up.

Adult↗
PubMed1990

Morphology of the condyles and mandibular fossa as seen by computed tomography.

Computed tomography allows detailed three-dimensional examination of the hard and soft tissue of the temporomandibular joint. The morphology of the mandibular fossa and the condyles together with the horizontal and vertical condylar inclinations was determined in 25 patients with temporomandibular joint dysfunction and 29 controls by use of axial and coronal computed tomography projections. The shape of the condyle was evaluated according to its general appearance. The temporomandibular joint measurements obtained by computed tomography were in good agreement with morphologic studies performed on dry skulls and autopsy material.

Adolescent↗
PubMed1995

[Third dimension and craniofacial plastic surgery].

Via an inverse approach to that of the Renaissance painter's treatment of perspective, the third dimension must be obtained from flat radiological information in order to reconstitute (virtually and materially) the volumes which it analyses. These images are analysed mathematically by computer. The applications are and will be numerous, especially in cranio-maxillo-facial surgery. Surgical simulation, without claiming to assess their soft tissue repercussions, section and virtually reposition bone segments: symmetrization and correction of hypotrophy are easy to visualize; computer-assisted surgical teaching applications (endoscopic surgery) are discussed. Multimodal images superimpose information from various sources: operative views and pre-recorded images are available to the surgeon and guide him in his "surgical navigation". Prototyping of skeletal anatomical specimens (prior to tumour or soft tissue specimens) provides the therapist with a precise preoperative spatial configuration of the abnormalities to be corrected, and the reconstructions to be performed. These developments, and others to come, are the sole objective of 3D imaging, beautiful in itself, but ineffective alone.

Computer Simulation↗
PubMed1992

[Malignant fibrous histiocytoma: productive use of imaging procedures].

Malignant fibrous histiocytoma (MFH) of soft tissue is a rare tumor. We present a case of MFH in the bicipital muscle. Local muscle hypertrophy or lesions of the long tendon of the bicipital muscle may be a difficult differential diagnosis. This case is used for outlining advantages of ultrasound, computed tomography and magnetic resonance imaging. In conventional radiography MFH is seen as a soft-tissue tumor sometimes involving the bone. CT is the best way to test bone involvement. Tumor extension will be assessed with great accuracy by means of ultrasonics and magnetic resonance imaging (MRI).

Arm↗
PubMed1994

Intussusception: characteristic radiolucencies on the abdominal radiograph.

Six hundred and twenty-five sets of supine and erect abdominal radiographs of 288 patients with the confirmed diagnosis of intussusception (315 episodes) and 310 patients without intussusception were reviewed retrospectively to determine the characteristic radiographic features of intussusception. Among the patients with intussusception, 155 episodes (49%) showed a soft tissue mass and nearly half of these (71) showed characteristic radiolucencies (target, crescentic, or amorphous) in the soft tissue mass. Thirty-five episodes showed the radiolucencies on both the supine and erect radiographs; in 16 cases the type of radiolucency differed on the two films. In patients without intussusception, abnormal radiolucencies were seen in only seven cases (2.3%). Computed tomography performed prospectively in five patients showed the radiolucencies in the soft tissue mass to be intussuscepted mesenteric fat. We conclude that abnormal radiolucencies in the soft tissue mass on plain radiographs are characteristic of intussusception.

Adolescent↗
PubMed2003

Blunt trauma soft-tissue uptake on skeletal scintigraphy.

Muscle and soft-tissue uptake have been described numerous times in the literature in patients undergoing Tc-99m methylene diphosphonate skeletal scintigraphy following trauma. Many of these traumas range from electrical burns, intramuscular injections, sports-related trauma, and overexercising, to actual physical damage resulting in superficial bruising and skin discoloration. In this case the patient presented with continuing low back pain after falling down some stairs. Although the scan was essentially normal for bony trauma, subtle soft-tissue uptake was detected that was enhanced with the addition of single photon emission computed tomographic imaging and surface rendering.

Accidental Falls↗
PubMed1989

Magnetic resonance imaging of tumors of the upper aerodigestive tract.

Magnetic resonance imaging is rapidly becoming the study of choice for evaluating tumors of the larynx and pharynx. It is superior to computed tomography because of its multiplanar imaging capability and greater soft tissue contrast resolution. Other advantages are that it is a noninvasive procedure, gives three-dimensional images that are not degraded by bony or overshoot reconstruction artifacts, and is sensitive to flowing blood, thus obviating the use of x-ray techniques with IV contrast agents. MRI is particularly well suited to laryngeal and nasopharyngeal malignancies because the deep extent of these tumors is difficult to assess by clinical examination alone.

Follow-Up Studies↗
PubMedDate not supplied

[Current computerized systems for automatic analysis of electric cardiac signals].

The paper discusses the trend in developing the cardiosystems used at multidisciplinary therapeutical-and-prophylactic institutions, shows the evergrowing role of personal computers to expand the functional potentials of the cardiological systems, and considers the basic requirements for soft- and hardware.

Cardiovascular Physiological Phenomena↗