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Imaging System (imaging + system)
Kinds of Imaging System Selected AbstractsDIAGNOSIS OF COLONIC ADENOMAS BY NEW AUTOFLUORESCENCE IMAGING SYSTEM: A PILOT STUDYDIGESTIVE ENDOSCOPY, Issue 2007Noriya Uedo Detection and removal of adenoma by colonoscopy is an important means of preventing cancer. Autofluorescence endoscopy can visualize flat or isochromatic tumor that was not detectable by white light endoscopy by the difference in tissue fluorescence properties. Recently, a new autofluorescence imaging system (AFI, Olympus Medical Systems) using a combination of autofluorescence and reflection imaging has been developed. The purpose of the present paper was to investigate its feasibility in detection of colonic adenoma in a clinical setting. A total of 64 patients were randomly assigned to AFI or white light groups, and the distal sigmoid colon and the rectum was observed under autofluorescence or white light followed by the other mode of observation by a different endoscopist. The diagnostic ability of each method for detection of neoplasms was compared in relation to the histology as a reference standard. Sensitivity and specificity of AFI for detection of neoplastic polyps was 84% and 60%, respectively, and were similar to those of white light colonoscopy: 90% and 64%. Conventional colonoscopy overlooked more flat lesions including one adenocarcinoma. AFI has the potential to detect more flat lesions but efficacy was unable to be demonstrated in the restricted population. Further investigations are needed to determine optimum usage. [source] MAGNIFICATION ENDOSCOPIC VIEW OF AN EARLY GASTRIC CANCER USING ACETIC ACID AND NARROW-BAND IMAGING SYSTEMDIGESTIVE ENDOSCOPY, Issue 2006Hideki Toyoda A 62-year-old woman was referred to Mie University Hospital, Tsu, Japan, for examination of upper gastrointestinal tract. The conventional endoscopy showed a slightly depressed lesion on the greater curvature at the gastric body. The surface of surrounding non-neoplastic mucosa using magnification endoscopy with acetic acid was gyrus-villous pattern whereas the surface of the lesion was rough. Furthermore, magnification endoscopy using acetic acid and narrow-band imaging system visualized clearer fine surface pattern of carcinoma. The lesion had a rough mucosa with irregularly arranged small pits. The lesion was resected completely by endoscopic mucosal resection with insulated-tip electrosurgical knife. Narrow-band imaging system with acetic acid may be able to visualize not only the capillary pattern but also the fine surface pattern of gastric carcinoma. [source] OPTICAL/DIGITAL CHROMOENDOSCOPY DURING COLONOSCOPY USING NARROW-BAND IMAGING SYSTEMDIGESTIVE ENDOSCOPY, Issue 2005Yasushi Sano This review is regarding the narrow-band imaging (NBI) system which has been developed at National Cancer Center Hospital East, Japan. The technology of the NBI system is based on modifying the spectral features by narrowing the bandwidth of spectral transmittance using various optical filters. The NBI system consists of three filters, 415,30 nm, 445,30 nm, and 500,30 nm, which are used as observing the fine capillaries in the superficial mucosa is essential to identify gastrointestinal neoplasms. The NBI system has been in development since 1999 and the first report of it's efficacy for gastrointestinal tract use was reported in 2001. In our pilot study, the NBI system may be sufficient to differentiate hyperplastic polyp from adenomatous polyp, and to visualize neoplasia with image processing in real-time during colonoscopy without the need for dye spraying. Herein, we propose the term ,optical/digital chromoendoscopy' using the NBI system and hope that this instrument will become standard endoscopy for in the 21st century. To estimate the feasibility and efficacy of using the NBI system for surveillance or screening examination, randomized control trials should be conducted in the future. [source] Comparison of the sensitivity of conventional cytology and the ThinPrep Imaging System for 1,083 biopsy confirmed high-grade squamous lesions,DIAGNOSTIC CYTOPATHOLOGY, Issue 5 2010C.T. (A.S.C.), C.T. (I.A.C.), J. A. Halford B.App.Sc. Abstract Liquid-based cytology continues to be utilized as an adjunct to conventional cytology in most Australian laboratories, even though a direct-to-vial ThinPrep protocol has been introduced in many countries with established cervical screening programs. Manual screening of ThinPrep slides has been widely practiced for more than 10 years and the recent introduction of the ThinPrep Imaging System (TPI) has been reported as being more sensitive than the conventional smear (CS) in the identification of high-grade cervical disease. We report our experience with ThinPrep Imaging since its introduction into our routine gynecological cytology service. 87,284 split sample pairs reported using the Imaging System demonstrated a decrease in unsatisfactory reports (3.65% for CS and 0.87% for TPI) and an increase in possible high grade and definite high-grade squamous reports (1.57% for CS and 1.62% for TPI). For 1,083 biopsy confirmed high-grade lesions, the correct diagnosis of high grade or possible high-grade squamous disease was made on the ThinPrep imaged slide in 61.0% (661/1,083) of cases and on the CS in 59.4% (643/1,083). This was not statistically significant. When all abnormalities identified on cytology were considered, including possible low grade and definite low-grade abnormalities, the difference in sensitivity for Thinprep imaged slides of 96.0% (1,040/1,083) and CSs of 91.6% (992/1,083) was statistically significant. Diagn. Cytopathol. 2010. © 2009 Wiley-Liss, Inc. [source] Alpha-methylacyl-CoA racemase: a multi-institutional study of a new prostate cancer markerHISTOPATHOLOGY, Issue 3 2004Z Jiang Aim :,To test whether ,-methylacyl-CoA racemase (AMACR) is a sensitive and specific marker of prostate cancer. Methods and results :,The expression levels of AMACR mRNA were measured by real-time polymerase chain reaction. A total of 807 prostatic specimens were further examined by immunohistochemistry specific for AMACR. Quantitative immunostaining analyses were carried out by using the ChromaVision Automated Cellular Imaging System and the Ariol SL-50 Imaging System, respectively. AMACR mRNA levels measured in prostatic adenocarcinoma were 55 times higher than those in benign prostate tissue. Of 454 cases of prostatic adenocarcinoma, 441 were positive for AMACR, while 254 of 277 cases of benign prostate were negative for AMACR. The sensitivity and specificity of AMACR immunodetection of prostatic adenocarcinomas were 97% and 92%, respectively. Both positive and negative predictive values were 95%. By automatic imaging analyses, the AMACR immunostaining intensity and percentage in prostatic adenocarcinomas were also significantly higher than those in benign prostatic tissue (105.9 versus 16.1 for intensity, 45.7% versus 0.02% and 35.03% versus 4.64% for percentage, respectively). Conclusions :,We have demonstrated the promising features of AMACR as a biomarker for prostate cancer in this large series and the potential to develop automated quantitative diagnostic tests. [source] Pulmonary Vein Disconnection Using the LocaLisa Three-Dimensional Nonfluoroscopic Catheter Imaging SystemJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2003Laurent Macle M.D. Introduction: Catheter ablation for atrial fibrillation (AF) is associated with prolonged fluoroscopy times. We prospectively evaluated the use of the LocaLisa three-dimensional nonfluoroscopic catheter imaging system with the aim of reducing fluoroscopy times during pulmonary vein (PV) disconnection. Methods and Results: Fifty-two patients with AF (47 men and 5 women, mean age 53 ± 9 years) underwent disconnection of all four PVs guided by a circumferential mapping catheter. The LocaLisa navigation system was used for real-time three-dimensional nonfluoroscopic imaging of the circumferential mapping catheter and ablation catheter electrodes in 26 patients. Procedural parameters were compared with those of a control group consisting of 26 patients in whom only standard fluoroscopy was used. PV disconnection was performed similarly in both groups by circumferential ablation around the ostia, with the endpoint of disconnecting left atrium to PV breakthroughs. The cumulative duration of radiofrequency (RF) energy delivery, procedural time, and fluoroscopy time required for PV disconnection were compared. Successful disconnection was achieved in all PVs, without acute complications. There was no significant difference in cumulative RF energy delivery: 34.8 ± 11.4 minutes for the nonfluoroscopic imaging group versus 38.2 ± 10.5 minutes for the control group. The fluoroscopy time required for disconnection of all four PVs was significantly lower in the LocaLisa group than in the control group: 8.4 ± 4.3 minutes versus 23.7 ± 9.7 minutes (P < 0.0001). There also was a significant difference in the mean time taken for PV disconnection: 46.5 ± 12.0 minutes for the nonfluoroscopic imaging group versus 66.3 ± 18.9 minutes for the control group (P < 0.0001). Conclusion: By allowing continuous three-dimensional monitoring of ablation and mapping catheter position and orientation, the LocaLisa nonfluoroscopic imaging system significantly reduces fluoroscopy and PV disconnection times. (J Cardiovasc Electrophysiol, Vol. 14, pp. 693,697, July 2003) [source] Image analysis systems for the detection of disseminated breast cancer cells on bone-marrow cytospinsJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 3 2005Sven Becker Abstract We assessed the accuracy of automated cell imaging systems when compared to manual evaluation of cytospin slides in determining the presence of cytokeratin-positive, disseminated breast cancer cells in bone marrow aspirates. A total of 298 cytospin slides of bone marrow aspirates were first evaluated by individual screening by one expert immunocytologist. Subsequently, all 298 slides were evaluated by the Automated Cell Imaging System (ACIS) by ChromaVisionÔ. Two separate analysis cycles were performed using ACIS. The results of the two ACIS analysis cycles were almost identical: in 293 out of 298 samples (98.3%), identical numbers of disseminated breast cancer cells were detected. In the remaining five samples (1.7%), the result of the two ACIS analysis cycles differed by only one tumor cell. By using the manual technique, 120 cytospin samples were found to be positive. ACIS was able to detect additional tumor cells in 64 cases. Not once did ACIS miss tumor cells when compared to the manual technique. Using ACIS, we were able to determine the bone marrow status of patients with nonmetastatic breast cancer faster, with greater accuracy, and with greater reproducibility than with the manual technique. J. Clin. Lab. Anal. 19:115,119, 2005. © 2005 Wiley-Liss, Inc. [source] Measuring stellar magnetic fields with the low-resolution spectropolarimeter of the William Herschel TelescopeMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007F. Leone ABSTRACT Although the influence of magnetic fields on the structure and evolution of stars has, to a great extent, been demonstrated theoretically, observational evidence for this in non-degenerated stars is still rather scarce and is mainly restricted to bright objects (V < 10). Stellar magnetic fields are commonly measured on the basis of circular spectropolarimetry at high/middle resolution across the profile of metal lines. The level of sensitivity of telescopes and spectrographs at present makes this still an almost impossible method for faint stars. In principle, stellar magnetic fields can also be measured on the basis of low-resolution spectropolarimetry, and very important results have been obtained at the 8-m European Southern Observatory telescopes with the Focal Reducer and Low-Dispersion Spectrograph (FORS1). The trade-off between signal-to-noise ratio (S/N) and spectral resolution in measuring stellar magnetic fields justifies an attempt, presented here, to perform these measurements at the 4.5-m William Herschel Telescope. One of the stars with the weakest known magnetic field, HD 3360, and the magnetic chemically peculiar stars, HD 10783, HD 74521 and HD 201601, have been observed with the Intermediate Dispersion Spectrograph and Imaging System (ISIS) in the 3785,4480 Å range. The measured stellar magnetic fields, from Stokes I and V spectra with S/N > 600, show an internal error of ,50 G when selecting the whole interval and ,200 G within a Balmer line. Ripples in the Stokes V spectra of HD 3360 result in an instrumental positive magnetic field certainly no larger than 80 G. [source] Implantable Imaging System for Visual ProsthesisARTIFICIAL ORGANS, Issue 6 2010Chuanqing Zhou Abstract In order to propose a method of intraocular imaging system for the visual prosthesis, an implantable microcamera was developed and evaluated in vivo. The microcamera was specially developed and shaped to fit the rabbit's lens capsule and encapsulated with the biocompatible silicone. To evaluate the feasibility of this novel approach, the custom-built device was implanted following the surgical extraction of rabbit's lens. And clinical examinations were performed 1 day, 3 days, 1 week, 2 week, and 1 month postoperatively, including slit-lamp examination, intraocular pressure, wound status, anterior chamber depth, the presence of the iris fibrosi of neovascularization, and the position of the implant. Real-time imaging was performed in vivo 1 month after the operation, and the acquired images were processed with the software and hardware that were specially developed for generating the stimulating pulses. Short-term results showed the novel approach is promising. [source] Super-LOTIS (Livermore Optical Transient Imaging System)ASTRONOMISCHE NACHRICHTEN, Issue 6-8 2004D. Pérez-Ramírez Abstract The 0.6-m Super-LOTIS telescope is a fully robotic system dedicated to the search for prompt optical emission from gamma-ray bursts (GRBs). The telescope began routine operations from its Steward Observatory site atop Kitt Peak (KPNO) in April 2000. This system is capable of responding to the Gamma-ray burst Coordinate Network (GCN) triggers within seconds. Together with LOTIS, these systems have been monitoring the GCN real-time data for automatic HETE2 GRB triggers. We will summarize the current capabilities of the system and present recent scientific results. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Comparability of three-dimensional optic disc imaging with different techniquesACTA OPHTHALMOLOGICA, Issue 1 2000A study with confocal scanning laser tomography, raster tomography ABSTRACT. Purpose: We wanted to compare optic nerve head topography measurements and discrimination between normal and glaucomatous eyes with two entirely different three-dimensional optic disc imaging techniques, confocal scanning laser tomography (Heidelberg Retina Tomograph, Heidelberg Engineering) and raster tomography (Glaucoma-Scope, Ophthalmic Imaging Systems). Methods: Both eyes of 225 normal subjects and 229 eyes of 166 patients with glaucoma at different stages were imaged with the Heidelberg Retina Tomograph and the Glaucoma-Scope. Optics discs were analysed in 15° sectors around the circumference. Depth measurements were calibrated on objects with known dimensions. Results: We observed no significant differences in absolute measurements of maximum cup depth and cup area between the two instruments. We observed small differences in absolute measurements of disc anti rim area between the two instruments. Discrimination between normal and glaucomatous eyes was close to identical for the two instruments. Both instruments had the same ability to distinguish glaucomatous regional alterations of optic nerve head topography from normal disc configuration. Conclusion: Both instruments while using entirely different principles for three-dimensional optic disc imaging gave very similar results. This correspondence of results implies that the same optic disc parameters can be analysed, and the results interpreted similarly for both methods, and probably with other three-dimensional imaging instruments. It may also indicate that results of studies with one of the instruments have general validity. [source] Quantitative Analysis of Tympanic Membrane Disease Using Video-Otoscopy ,THE LARYNGOSCOPE, Issue 10 2000Vikram J. Jaisinghani MD Abstract Objective To perform quantitative analysis of pathological changes in the tympanic membrane using video-otoscopic images. Study Design Prospective case-control study. Methods Forty-two ears of children with chronic otitis media with effusion (OME) and 15 ears of normal children were included in this study. Tympanic membrane images were captured and digitized using a Welch-Allyn (Skaneatales Falls, NY) VDX-300 Illumination and Imaging system with S-VHS input to a MIRO DC 30 (Pinnacle Systems, Mountain View, CA) visual board in a Power PC,based computer. These images were visualized and recorded during static and pneumatic pressure changes. Quantitative analysis of tympanic membrane disease was performed using Image Pro Plus Imaging software (Media Cybernetics, Del Mar, CA). The measurements included area of the tympanic membrane and its quadrants, area of tympanic membrane involved by disease, angle formed at the umbo, and length of the malleus versus vertical length of the tympanic membrane. Results Tympanosclerosis was present in 57% of ears and occurred most frequently in the anteroinferior quadrant, but the ma-imum area of involvement was in the posteroinferior quadrant. The ratio of the angles formed at the umbo was significantly greater (P = .01) for the OME group compared with the control group. The ratio of the length of the umbo and the vertical length of the tympanic membrane was almost identical for the OME and the control groups (P = .4). Conclusions Video-otoscopic images can be used for quantitative analysis of tympanic membrane disease. The ratio of the posterior angle to the anterior angle formed at the umbo seems to be a more reliable indicator of post otitis media than is a reduced length of the long process of malleus. [source] 3D In-Vivo Optical Skin Imaging for Topographical Quantitative Assessment of Non-Ablative Laser TechnologyDERMATOLOGIC SURGERY, Issue 3 2002Paul M. Friedman MD background. A new method for treating facial rhytides and acne scars with nonablative laser and light source techniques has recently been introduced. Given the inherent limitations of photographic and clinical evaluation to assess subtle changes in rhytides and surface topography, a new noninvasive objective assessment is required to accurately assess the outcomes of these procedures. objective. The purpose of this study was to measure and objectively quantify facial skin using a novel, noninvasive, In-vivo method for assessing three-dimensional topography. This device was used to quantify the efficacy of five treatment sessions with the 1064 nm QS Nd:YAG laser for rhytides and acne scarring, for up to six months following laser treatment. methods. Two subjects undergoing facial rejuvenation procedures were analyzed before and after therapy using a 30-mm, three-dimensional microtopography imaging system (PRIMOS, GFM, Teltow, Germany). The imaging system projects light on to a specific surface of the skin using a Digital Micromirror Device (DMDÔ Texas Instruments, Irving, TX) and records the image with a CCD camera. Skin Surface microtopography is reconstructed using temporal phase shift algorithms to generate three-dimensional images. Measurements were taken at baseline, at various times during the treatment protocol, and then at three and six-month follow-up visits. Silicone skin replicas (FLEXICO, Herts, England) were also made before and after the laser treatment protocol for comparison to In-vivo acquisition. results. Skin roughness decreased by 11% from baseline after three treatment sessions in the wrinkles subject, while a 26% improvement of skin roughness was recorded by 3D In-vivo assessment six months following the fifth treatment session. The subject with acne scarring demonstrated a 33% decrease in roughness analysis after three treatment sessions by 3D In-vivo assessment. A 61% improvement in surface topography was recorded 3-months following the fifth treatment session, which was maintained at the 6-month follow-up. conclusion. Three-dimensional In-vivo optical skin imaging provided a rapid and quantitative assessment of surface topography and facial fine lines following multiple treatment sessions with a 1064-nm QS Nd:YAG laser, correlating with clinical and subjective responses. This imaging technique provided objective verification and technical understanding of nonablative laser technology. Wrinkle depth and skin roughness decreased at the three and six-month follow-up evaluations by 3D In-vivo assessment, indicating ongoing dermal collagen remodeling after the laser treatment protocol. Future applications may include comparison of nonablative laser technology, optimization of treatment regimens, and objective evaluation of other aesthetic procedures performed by dermatologists. [source] DIAGNOSIS OF COLONIC ADENOMAS BY NEW AUTOFLUORESCENCE IMAGING SYSTEM: A PILOT STUDYDIGESTIVE ENDOSCOPY, Issue 2007Noriya Uedo Detection and removal of adenoma by colonoscopy is an important means of preventing cancer. Autofluorescence endoscopy can visualize flat or isochromatic tumor that was not detectable by white light endoscopy by the difference in tissue fluorescence properties. Recently, a new autofluorescence imaging system (AFI, Olympus Medical Systems) using a combination of autofluorescence and reflection imaging has been developed. The purpose of the present paper was to investigate its feasibility in detection of colonic adenoma in a clinical setting. A total of 64 patients were randomly assigned to AFI or white light groups, and the distal sigmoid colon and the rectum was observed under autofluorescence or white light followed by the other mode of observation by a different endoscopist. The diagnostic ability of each method for detection of neoplasms was compared in relation to the histology as a reference standard. Sensitivity and specificity of AFI for detection of neoplastic polyps was 84% and 60%, respectively, and were similar to those of white light colonoscopy: 90% and 64%. Conventional colonoscopy overlooked more flat lesions including one adenocarcinoma. AFI has the potential to detect more flat lesions but efficacy was unable to be demonstrated in the restricted population. Further investigations are needed to determine optimum usage. [source] MAGNIFICATION ENDOSCOPIC VIEW OF AN EARLY GASTRIC CANCER USING ACETIC ACID AND NARROW-BAND IMAGING SYSTEMDIGESTIVE ENDOSCOPY, Issue 2006Hideki Toyoda A 62-year-old woman was referred to Mie University Hospital, Tsu, Japan, for examination of upper gastrointestinal tract. The conventional endoscopy showed a slightly depressed lesion on the greater curvature at the gastric body. The surface of surrounding non-neoplastic mucosa using magnification endoscopy with acetic acid was gyrus-villous pattern whereas the surface of the lesion was rough. Furthermore, magnification endoscopy using acetic acid and narrow-band imaging system visualized clearer fine surface pattern of carcinoma. The lesion had a rough mucosa with irregularly arranged small pits. The lesion was resected completely by endoscopic mucosal resection with insulated-tip electrosurgical knife. Narrow-band imaging system with acetic acid may be able to visualize not only the capillary pattern but also the fine surface pattern of gastric carcinoma. [source] Efficacy of magnifying chromoendoscopy for the differential diagnosis of colorectal lesions,DIGESTIVE ENDOSCOPY, Issue 2 2005Yasushi Sano Magnifying chromoendoscopy is an exciting new tool and offers detailed analysis of the morphological architecture of mucosal crypt orifices. In this review, we principally show the efficacy of magnifying chromoendoscopy for the differential diagnosis of colorectal lesions such as prediction between non-neoplastic lesions and neoplastic ones, and distinction between endoscopically treatable early invasive cancers and untreatable cancers based on a review of the literature and our experience at two National Cancer Centers in Japan. Overall diagnostic accuracy by conventional view, chromoendoscopy and chromoendoscopy with magnification ranged from 68% to 83%, 82% to 92%, and 80% to 96%, respectively, and diagnostic accuracy of accessing the stage of early colorectal cancer using magnifying colonoscopy was over 85%. Although the reliability depends on the skill in magnifying observation, widespread applications of the magnification technique could influence the indications for biopsy sampling during colonoscopy and the indication for mucosectomy. Moreover, the new detailed images seen with magnifying chromoendoscopy are the beginning of a new period in which new optical developments, such as narrow band imaging system, endocytoscopy system, and laser-scanning confocal microscopy, will allow a unique look at glandular and cellular structures. [source] Three-dimensional endoscopic ultrasonography for the assessment of early gastric carcinoma invasion: could it provide diagnostic innovations?DIGESTIVE ENDOSCOPY, Issue 2 2002EMAN A. SABET Background: This study aimed to evaluate a three-dimensional endoscopic ultrasonographic (3-D EUS) system in the assessment of the tumor invasion depth of early gastric carcinoma. Methods: Sixty-nine macroscopically early cancer lesions in 67 patients were recruited in an in vivo study. The surgically resected gastric specimens of 30 of them were re-examined in an ex vivo study. An Olympus 3-D EUS imaging system was employed in both studies. Diagnostic accuracy for tumor invasion depth was evaluated and compared with histopathological sections stained by H&E and Masson's trichrome stain. Reconstructed surface-rendering images were evaluated and compared with the endoscopic and macroscopic findings. Results: Three-dimensional EUS allowed rapid tomographic assessment of the lesions in both the in vivo and ex vivo studies. The accuracy of 3-D EUS for the assessment of tumor invasion depth was 87% in the in vivo study. The accuracy rate was significantly lower (P = 0.03) for the cancer lesions associated with ulcer fibrosis (74%) than for those with no fibrosis (97%). In the 30 subjects who underwent both studies, the accuracy rates were higher in the ex vivo than the in vivo study (94%vs 77% for all the lesions, and 93%vs 74% for cancers associated with fibrosis), but were not statistically significant. The rates of good surface-rendering images were 64% and 94% in the in vivo and ex vivo studies, respectively. The differences were attributed to the clearer dual-plane reconstruction images obtained in the ex vivo study in absence of motion artifacts. Conclusions: Three-dimensional EUS is a promising imaging technique for the assessment of tumor invasion depth of early gastric cancer. [source] Cerebral blood flow in patients with diffuse axonal injury , examination of the easy Z -score imaging system utilityEUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2007T. Okamoto To evaluate the utility of easy Z -score imaging system (eZIS) in 27 diffuse axonal injury (DAI) cases. Twenty-seven DAI patients were examined with an magnetic resonance imaging (MRI) T2* sequence and with eZIS (seven women, 20 men; age range, 19,35 years; median age: 26.6 years). In this investigation, we excluded patients who exhibited complications such as acute subdural hematoma, acute epidural hematoma, intracerebral hematoma, or brain contusion. We examined the neuropsychological tests and correlated with findings from MRI/eZIS. Furthermore, we evaluated the degree of ventricular enlargement in the bifrontal cerebroventricular index (CVI). Patients were divided into two groups: the enlargement group (bifrontal CVI > 35%, 12 patients) and the non-enlargement group (bifrontal CVI < 35%, 15 patients). All of the patients showed cognitive deficits as observed from the neuropsycological test results. Fifteen out of 27 patients by MRI T1/T2 weighted images and fluid attenuated inversion recovery (FLAIR), 22 out of 27 patients by MRI T2* weighted images and 24 out of 27 patients by eZIS showed abnormal findings. In MRI T2* weighted imaging, the white matter from the frontal lobe, corpus callosum, and brainstem showed abnormal findings. With eZIS, 22 patients (81.5%) showed blood flow degradation in the frontal lobe, and 12 patients (44.4%) in cingulate gyrus. In the enlargement group, Functional Independence Measure, Mini-Mental State Examination, Verbal IQ (VIQ)/Full Scale IQ (FIQ), Trail Making Test-B (TMT-B), and Non-paired of Miyake Paired Test were significantly lower. Amongst 12 patients without ventricular enlargement who had no abnormal findings in MRI T1/T2 weighted images and FLAIR, abnormal findings were detectable in seven patients with MRI T2* weighted imaging and to 10 patients with eZIS. Results of the MRI examination alone cannot fully explain DAI frontal lobe dysfunction. However, addition of the eZIS-assisted analysis derived from the single photon emission computed tomography (SPECT) data enabled us to understand regions where blood flow was decreased, i.e., where neuronal functions conceivably might be reduced. [source] Detection of artificially induced vertical radicular fractures using Tuned Aperture Computed TomographyEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2001Madhu K. Nair This study compared the accuracy of three imaging modalities for the detection of artificially induced vertical root fractures (VRF) on teeth in cadaver mandibles. Fifty-four single-rooted, endodontically treated mandibular teeth being prepared to carry posts were evaluated using direct digital radiography (DDI) with a Schick sensor, unprocessed Tuned Aperture Computed Tomography® (TACT-U) images and iteratively restored TACT (TACT-IR) images. Twenty-eight of these teeth had been subjected to fracture induction using an apically driven force. Nine basis images were used for each TACT image generation. Eight observers used a five-point confidence rating scale to record the confidence with which they considered a fracture to be present or not. Sensitivity and specificity values were computed and receiver operating characteristic (ROC) curves were generated. The areas under the curves (Az) used as an indication of the diagnostic accuracy of the imaging system were as follows: DDI: 0.37; TACT-U: 0.77 and TACT-IR: 0.81. DDI was significantly inferior to the TACT modalities. Differences in detection efficacy based on observers and observation sessions were noted on ANOVA and post-hoc Tukey's tests. This study indicates that TACT is the imaging modality of choice for VRF in endodontically treated teeth. [source] Disparity between prostate tumor interior versus peripheral vasculature in response to verteporfin-mediated vascular-targeting therapyINTERNATIONAL JOURNAL OF CANCER, Issue 3 2008Bin Chen Abstract Photodynamic therapy (PDT) is a light-based cancer treatment modality. Here we employed both in vivo and ex vivo fluorescence imaging to visualize vascular response and tumor cell survival after verteporfin-mediated PDT designed to target tumor vasculature. EGFP-MatLyLu prostate tumor cells, transduced with EGFP using lentivirus vectors, were implanted in athymic nude mice. Immediately after PDT with different doses of verteporfin, tumor-bearing animals were injected with a fluorochrome-labeled albumin. The extravasation of fluorescent albumin along with tumor EGFP fluorescence was monitored noninvasively with a whole-body fluorescence imaging system. Ex vivo fluorescence microscopy was performed on frozen sections of tumor tissues taken at different times after treatment. Both in vivo and ex vivo imaging demonstrated that vascular-targeting PDT with verteporfin significantly increased the extravasation of fluorochrome-labeled albumin in the tumor tissue, especially in the tumor periphery. Although PDT induced substantial vascular shutdown in interior blood vessels, some peripheral tumor vessels were able to maintain perfusion function up to 24 hr after treatment. As a result, viable tumor cells were typically detected in the tumor periphery in spite of extensive tumor cell death. Our results demonstrate that vascular-targeting PDT with verteporfin causes a dose- and time-dependent increase in vascular permeability and decrease in blood perfusion. However, compared to the interior blood vessels, peripheral tumor blood vessels were found less sensitive to PDT-induced vascular shutdown, which was associated with subsequent tumor recurrence in the tumor periphery. © 2008 Wiley-Liss, Inc. [source] High-resolution imaging using integrated optical systemsINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 2 2004S. Prasad Abstract Certain optical aberrations, such as defocus, can significantly degrade the signal collected by an imaging system, producing images with low resolution. In images with depth-dependent detail, such degradations are difficult to remove due to their inherent spatially varying nature. In 1995, Dowski and Cathey introduced the concept of wavefront coding to extend the depth of field. They showed that wavefront coding and decoding enables quality control of such images using integrated optical-digital imaging systems. With wavefront coding, a high-resolution image can be efficiently obtained without the need to resort to expensive algorithms for spatially varying restoration. In this article, we discuss a novel and effective multiple-design-parameter approach for optimizing the processes of encoding and decoding the wavefront phase in integrated optical-digital imaging systems. Our approach involves the use of information metrics, such as the Strehl ratio and Fisher information, for determining the optimal pupil-phase distribution for which the resulting image is insensitive to certain aberrations, such as focus errors. The effectiveness of this approach is illustrated with a number of numerical simulation experiments, and applications to the development of iris recognition systems with high-resolution capabilities are briefly discussed. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 67,74, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20009 [source] Intensity-based image matching for regular firearmsINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 2 2002S.S. Murthy Abstract This paper reports the digitized image matching of intensity-based signals generated by the POLIVIEW imaging system for regular firearms. The POLIVIEW imaging system transforms nonlinearized models into linearized models by applying a differential matching method. This paper also discusses the performance of the computer program for determining the peaks of the histograms generated and their threshold segmentation for matching. This method can be used to generate corroborative evidence in solving crimes. © 2002 Wiley Periodicals, Inc. Int J Imaging Syst Technol 12, 68,72, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10011 [source] Superresolution planar diffraction tomography through evanescent fields,INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 1 2002Sean K. Lehman We consider the problem of noninvasively locating objects buried in a layered medium such as land mines in the ground or objects concealed in a wall. In such environments, the transmitter(s) and receiver(s) are frequently within the near-field region of the illuminating radiation. In these cases, the scattered evanescent field carries useful information on the scattering object. Conventional diffraction tomography techniques neglect, by their design, the evanescent field. Under near-field conditions, they treat it as noise as opposed to valid data. If correctly incorporated into a reconstruction algorithm, the evanescent field, which carries high spatial frequency information, can be used to achieve resolution beyond the classical limit of ,/2, or "superresolution." We build on the generalized holography theory presented by Langenberg to develop a planar diffraction tomography algorithm that incorporates evanescent field information to achieve superresolution. Our theory is based on a generalization of the Fourier transform, which allows for complex spatial frequencies in a manner similar to the Laplace transform. We specialize our model to the case of a two-dimensional multimonostatic, wideband imaging system, and derive an extended resolution reconstruction procedure. We implement and apply our reconstruction to two data sets collected using the Lawrence Livermore National Laboratory (LLNL) Micropower Impulse Radar (MIR). © 2002 John Wiley & Sons, Inc. Int J Imaging Syst Technol 12, 16,26, 2002 [source] Visualization of the foaming mechanism of polyethylene blown by chemical blowing agents under ambient pressureADVANCES IN POLYMER TECHNOLOGY, Issue 4 2007Remon Pop-Iliev Abstract Understanding the fundamental mechanisms that govern the foaming process is the most essential universal prerequisite for developing effective processing strategies for fabricating high-quality foamed plastic products using any type of foaming technology. Despite chemically blown foaming of thermoplastics under atmospheric pressure has been successfully implemented in rotational foam molding over the last decade, the related open literature does not provide substantial research addressing the fundamentals of this unique foaming mechanism. The present study focuses on clarifying the fundamental foaming mechanisms that govern the successful manufacture of thermoplastic foams using a chemical blowing agent under low-pressure (atmospheric) conditions. The presented research is mainly based on observing a series of visualization experiments conducted using a custom-made visualization system including an optical microscope and a computerized CCD camera imaging system, which was utilized for investigating the behavior of foamable polyethylene samples prepared by using the compression-molding method. © 2008 Wiley Periodicals, Inc. Adv Polym Techn 26:213,222, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20102 [source] Quantitative Ultrasound Does Not Reflect Mechanically Induced Damage in Human Cancellous BoneJOURNAL OF BONE AND MINERAL RESEARCH, Issue 12 2000P. H. F. Nicholson Abstract This study investigated the ability of quantitative ultrasound (QUS) to detect reductions in the elastic modulus of cancellous bone caused by mechanical damage. Ultrasonic velocity and attenuation were measured using an in-house parametric imaging system in 46 cancellous bone cores from the human calcaneus. Each core was subjected to a mechanical testing regime to (a) determine the predamage elastic modulus, (b) induce damage by applying specified strains in excess of the yield strain, and (c) measure the postdamage elastic modulus. The specimens were divided into four groups: a control group subjected to a nominally nondestructive 0.7% maximum strain (,m) and three damage groups subjected to increasing strain levels (,m = 1.5, 3.0, and 4.5%). QUS measurements before and after the mechanical testing showed no significant differences between the control group and damage groups, despite highly significant (p < 0.001) reductions in the elastic modulus of up to 72%. These results indicate that current QUS techniques do not intrinsically reflect the elastic properties of cancellous bone. This is consistent with ultrasonic properties being determined by other factors (apparent density and/or architecture), which normally are associated strongly with elastic properties, but only when bone is mechanically intact. Clinically, this implies that ultrasound cannot be expected to detect bone fragility in the absence of major changes in bone density and/or trabecular architecture. [source] Real-time Visualization and Quantification of Retrograde Cardioplegia Delivery using Near Infrared Fluorescent ImagingJOURNAL OF CARDIAC SURGERY, Issue 6 2008Aravind T. Rangaraj M.D. Presently, there exist no established methods to quantitatively assess cardioplegia distribution intraoperatively and determine when retrograde cardioplegia is required. In this study, we evaluate the feasibility of near infrared (NIR) imaging for real-time visualization of cardioplegia distribution in a porcine model. Methods: A portable, intraoperative, real-time NIR imaging system was utilized. NIR fluorescent cardioplegia solution was developed by incorporating indocyanine green (ICG) into crystalloid cardioplegia solution. Real-time NIR imaging was performed while the fluorescent cardioplegia solution was infused via the retrograde route in five ex vivo normal porcine hearts and in five ex vivo porcine hearts status post left anterior descending (LAD) coronary artery ligation. Horizontal cross-sections of the hearts were obtained at proximal, middle, and distal LAD levels. Videodensitometry was performed to quantify distribution of fluorophore content. Results: The progressive distribution of cardioplegia was clearly visualized with NIR imaging. Complete visualization of retrograde distribution occurred within 4 minutes of infusion. Videodensitometry revealed retrograde cardioplegia, primarily distributed to the left ventricle (LV) and anterior septum. In hearts with LAD ligation, antegrade cardioplegia did not distribute to the anterior LV. This deficiency was compensated for with retrograde cardioplegia supplementation. Conclusions: Incorporation of ICG into cardioplegia allows real-time visualization of cardioplegia delivery via NIR imaging. This technology may prove useful in guiding intraoperative decisions pertaining to when retrograde cardioplegia is mandated. [source] A Tissue-Specific Model of Reentry in the Right Atrial AppendageJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2009JICHAO ZHAO Ph.D. Introduction: Atrial fibrillation is prevalent in the elderly and contributes to mortality in congestive heart failure. Development of computer models of atrial electrical activation that incorporate realistic structures provides a means of investigating the mechanisms that initiate and maintain reentrant atrial arrhythmia. As a step toward this, we have developed a model of the right atrial appendage (RAA) including detailed geometry of the pectinate muscles (PM) and crista terminalis (CT) with high spatial resolution, as well as complete fiber architecture. Methods and Results: Detailed structural images of a pig RAA were acquired using a semiautomated extended-volume imaging system. The generally accepted anisotropic ratio of 10:1 was adopted in the computer model. To deal with the regional action potential duration heterogeneity in the RAA, a Courtemanche cell model and a Luo-Rudy cell model were used for the CT and PM, respectively. Activation through the CT and PM network was adequately reproduced with acceptable accuracy using reduced-order computer models. Using a train of reducing cycle length stimuli applied to a CT/PM junction, we observed functional block both parallel with and perpendicular to the axis of the CT. Conclusion: With stimulation from the CT at the junction of a PM, we conclude: (a) that conduction block within the CT is due to a reduced safety factor; and (b) that unidirectional block and reentry within the CT is due to its high anisotropy. Regional differences in effective refractive period do not explain the observed conduction block. [source] Characterization of a New Pulmonary Vein Variant Using Magnetic Resonance Angiography:JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2004Imaging, Incidence, Interventional Implications of the "Right Top Pulmonary Vein" Introduction: Catheter ablation of the pulmonary veins (PVs) for prevention of recurrent atrial fibrillation requires precise anatomic information. We describe the characteristics of a new anatomic variant of PV anatomy using magnetic resonance angiography. Methods and Results: A 1.5-T magnetic resonance imaging system with a body coil or a torso phased-array coil was used before and after gadolinium injection. Magnetic resonance angiograms were acquired with a breath-hold three-dimensional fast spoiled gradient-echo imaging sequence in the coronal plane. Three-dimensional reconstruction with maximum intensity projections and multiplanar reformations was performed. A newly described variant PV ascending from the roof of the left atrium was found in 3 of 91 subjects. The mean ostial diameter of the roof PV was 7 ± 2 mm, the mean distance from the ostium to the first branching point was 22 ± 8.5 mm, and the mean distance to the right superior PV was 3.3 ± 0.6 mm. Conclusion: We refer to the newly described variant of PV anatomy as the "right top pulmonary vein." It is important to be aware of this anatomic pattern to avoid inadvertent catheter intubation, which can result in misleading mapping results and PV stenosis. (J Cardiovasc Electrophysiol, Vol. 15, pp. 538-543, May 2004) [source] Pulmonary Vein Disconnection Using the LocaLisa Three-Dimensional Nonfluoroscopic Catheter Imaging SystemJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2003Laurent Macle M.D. Introduction: Catheter ablation for atrial fibrillation (AF) is associated with prolonged fluoroscopy times. We prospectively evaluated the use of the LocaLisa three-dimensional nonfluoroscopic catheter imaging system with the aim of reducing fluoroscopy times during pulmonary vein (PV) disconnection. Methods and Results: Fifty-two patients with AF (47 men and 5 women, mean age 53 ± 9 years) underwent disconnection of all four PVs guided by a circumferential mapping catheter. The LocaLisa navigation system was used for real-time three-dimensional nonfluoroscopic imaging of the circumferential mapping catheter and ablation catheter electrodes in 26 patients. Procedural parameters were compared with those of a control group consisting of 26 patients in whom only standard fluoroscopy was used. PV disconnection was performed similarly in both groups by circumferential ablation around the ostia, with the endpoint of disconnecting left atrium to PV breakthroughs. The cumulative duration of radiofrequency (RF) energy delivery, procedural time, and fluoroscopy time required for PV disconnection were compared. Successful disconnection was achieved in all PVs, without acute complications. There was no significant difference in cumulative RF energy delivery: 34.8 ± 11.4 minutes for the nonfluoroscopic imaging group versus 38.2 ± 10.5 minutes for the control group. The fluoroscopy time required for disconnection of all four PVs was significantly lower in the LocaLisa group than in the control group: 8.4 ± 4.3 minutes versus 23.7 ± 9.7 minutes (P < 0.0001). There also was a significant difference in the mean time taken for PV disconnection: 46.5 ± 12.0 minutes for the nonfluoroscopic imaging group versus 66.3 ± 18.9 minutes for the control group (P < 0.0001). Conclusion: By allowing continuous three-dimensional monitoring of ablation and mapping catheter position and orientation, the LocaLisa nonfluoroscopic imaging system significantly reduces fluoroscopy and PV disconnection times. (J Cardiovasc Electrophysiol, Vol. 14, pp. 693,697, July 2003) [source] Effect of Action Potential Duration and Conduction Velocity Restitution and Their Spatial Dispersion on Alternans and the Stability of ArrhythmiasJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2002ISABELLE BANVILLE Ph.D. Restitution and Spatial Heterogeneities vs Arrhythmias.Introduction: The slope of the action potential duration (APD) restitution curve has been used to explain wavebreaks during arrhythmia initiation and maintenance. This hypothesis remains incomplete to fully describe the experimental data. Other factors contributing to wavebreaks must be studied to further understand arrhythmia dynamics. Methods and Results: Control APDs were measured from isolated rabbit hearts using a monophasic action potential probe. APD and conduction velocity (CV) restitution were quantified over the heart surface for two drugs, diacetyl monoxime (DAM) and cytochalasin D (CytoD), using a dual camera video imaging system. For all pacing intervals: (1) control APDs were shorter than for CytoD but longer than for DAM; and (2) CV was greater for CytoD compared with DAM. APD dispersion increased as pacing interval decreased for both drugs. For DAM, increased dispersion was due to a difference in APD restitution between the right and left ventricle. For CytoD, increased dispersion was due to discordant alternans, with no significant spatial variation in restitution. Fibrillation was sustained only in the control hearts; with DAM, stable reentry was sustained with shorter APD and cycle length compared with CytoD for which only nonsustained unstable reentry occurred. Conclusion: Alternans and arrhythmia dynamics are affected by the spatial dispersion of APD restitution as well as CV restitution, not simply the slope of APD restitution. Therefore, a direct link of the APD restitution slope to alternans and arrhythmia dynamics in rabbit heart does not exist. Designing antiarrhythmic drugs to alter only the restitution slope may not be appropriate. [source] | ||||||||||||||||||||||||||||||||||||||||||||||