The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
M D Sherar - One of the best experts on this subject based on the ideXlab platform.
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B Scan ultrasound imaging of thermal coagulation in Bovine liver frequency shift attenuation mapping
Ultrasound in Medicine and Biology, 2001Co-Authors: Peter D Bevan, M D SherarAbstract:ABstract Thermal therapy is an experimental procedure to treat localised tumours in, for example, the prostate, liver, kidney or Breast. Following work that demonstrated a marked increase in the ultrasound (US) attenuation of tissues heated aBove 65°C, US attenuation estimation is proposed as a method to monitor the progression and extent of thermal therapy. In this study, B-Scan attenuation mapping techniques, Based on the shift in centre frequency of the US signal, are examined. A simple technique Based on the change of phase of the quadrature-demodulated signal is presented and analysed. Autoregressive analysis is also examined. It is shown with simulated data that these methods are effective at differentiating and localizing the attenuation change associated with tissue coagulation, But that, in the analysis of phantom or ex vivo Bovine liver data, electronic noise severely limits the effectiveness of these techniques. (E-mail: sherar@oci.utoronto.ca)
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B Scan ultrasound imaging of thermal coagulation in Bovine liver log envelope slope attenuation mapping
Ultrasound in Medicine and Biology, 2001Co-Authors: Peter D Bevan, M D SherarAbstract:ABstract Thermal therapy is an experimental procedure to treat localised tumours in the prostate, liver, kidney or Breast. Monitoring is important to ensure complete tumour destruction while sparing adjacent sensitive structures. Previous work demonstrated that, when Biological tissues are heated aBove 65°C, ultrasound (US) attenuation increases due to thermal coagulation of tissue. This study examined the feasiBility of a B-Scan, envelope-Based attenuation estimation method to monitor thermal therapy. The slope of the log of the signal envelope was used to estimate attenuation. It is shown that this method is aBle to demonstrate, from simulated and phantom data, a limited aBility to differentiate attenuation levels that correspond to thermally coagulated and uncoagulated Beef liver. In ex vivo Bovine liver, however, issues due to signal-to-noise ratio (SNR) of the signal envelope prevented the visulisation of a 2-cm diameter thermally coagulated inclusion. The limitations of this method are extended to the multinarrow-Band (MNB) technique. (E-mail:sherar@oci.utoronto.ca)
Nagahisa Yoshimura - One of the best experts on this subject based on the ideXlab platform.
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morphological features in anterior scleral inflammation using swept source optical coherence tomography with multiple B Scan averaging
British Journal of Ophthalmology, 2017Co-Authors: Yoshimasa Kuroda, Akihito Uji, Satoshi Morooka, Kazuaki Nishijima, Nagahisa YoshimuraAbstract:Background/aims To determine the morphological features of anterior scleral inflammation using swept-source optical coherence tomography. Methods In this retrospective oBservational study, we examined 17 eyes of 14 patients with diffuse anterior scleral inflammation and 13 eyes of 13 young unaffected patients. We compared cross-sectional images of the conjunctiva, episclera and sclera oBtained using swept-source optical coherence tomography equipped with a multiple B-Scan averaging process Between normal eyes and those with episcleritis and scleritis. Results Optical coherence tomography showed that the conjunctival stroma/episclera layer was notaBly swollen in diseased eyes. The eyes with diffuse anterior scleral inflammation had a significantly thicker conjunctival stroma/episclera than normal eyes (403.0 μm vs 288.0 μm, p=0.002). There was no significant difference in scleral stroma thickness Between eyes with anterior scleral inflammation and normal eyes (464.7 μm vs 434.2 μm, p=0.11). We separately analysed 11 eyes with diffuse scleritis and 6 eyes with diffuse episcleritis. While the conjunctival epithelium and conjunctival stroma/episclera were thicker in eyes with diffuse scleritis than in those with diffuse episcleritis (78.9 μm vs 50.4 μm, p=0.003 and 445.5 μm vs 308.8 μm, p=0.033, respectively), the scleral stroma thickness in eyes with diffuse scleritis was comparaBle with normal eyes (465.5 μm vs 434.2 μm, p=0.43). Conclusions The swelling of diffuse scleritis occurred within the episclera rather than in the scleral stroma. Since optical coherence tomography visualises the morphology of the episclera and sclera, it can Be useful for evaluating inflammation activity and therapeutic effects in diffuse scleritis.
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spectral domain optical coherence tomography with multiple B Scan averaging for enhanced imaging of retinal diseases
Ophthalmology, 2008Co-Authors: Atsushi Sakamoto, Masanori Hangai, Nagahisa YoshimuraAbstract:OBjective To determine whether multiple B-Scan averaging improves the quality of spectral-domain optical coherence tomography (SD OCT) images of the retina. Design Prospective cross-sectional study. Participants One hundred one eyes of 84 patients with various retinal diseases. Methods A prototype SD OCT system was used with a sensitivity of 98 deciBels, air axial resolution of 6.1 μm, and acquisition rate of approximately 18 700 axial Scans per second. To evaluate multiple B-Scan averaging, a set of 12 B-Scan images was oBtained at the identical retinal location and the multiple Scans were averaged using custom software; some images containing lateral eye motion were rejected. OBjective differences in image quality were measured By comparing the contrast-to-noise ratios (CNRs) for key retinal structures in unenhanced and enhanced images using non–repeated-measures analysis of variance and the Dennett post hoc test. SuBjective differences in image quality were evaluated By asking trained ophthalmologists independently to rank pairs of unenhanced and enhanced SD OCT images on a 5-point scale (upper or lower image definitely Better, slightly Better, or equal) and analyzing results using the Scheffe method for paired comparisons. Main Outcome Measures Contrast-to-noise ratio in enhanced versus unenhanced SD OCT images, expert comparison of image quality, and retinal pathologic features in enhanced versus unenhanced SD OCT images. Results Averaging >4 SD OCT Scans achieved significant improvement in CNR and also improved ophthalmologists' aBility to distinguish retinal structures. More than 4 Scans could Be averaged for 100 (99%) of the 101 eyes with retinal diseases in this study. Averaging >4 SD OCT Scans improved visualization of structures, such as aBnormalities in the photoreceptor layer and suB–retinal pigment epithelium (RPE) lesions, that could not Be identified clearly in single-Scan SD OCT images Because of various retinal pathologic features. These included intraretinal lesions that mask the underlying structures, such as cystoid macular edema and retinal hemorrhage, and inward shifting of the sensory retina Because of pigment epithelial detachment and lesions Beneath the RPE. Conclusions Multiple B-Scan averaging is an easy and practical method to improve the quality of retinal images oBtained By SD OCT and thereBy to improve the diagnosis and management of retinal diseases.
Shan C Lin - One of the best experts on this subject based on the ideXlab platform.
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ocular gossypiBoma ultrasound B Scan assessment of retained surgical sponge after ahmed valve surgery
Journal of Glaucoma, 2017Co-Authors: Kelly Babic, Christine Siguanbell, Michael Hee, Shan C LinAbstract:PURPOSE OF THE STUDY To present the first documented case of an ocular gossypiBoma (retained foreign Body) of a mitomycin-C-soaked sponge confirmed echographically using diagnostic ultrasound B-Scan after Ahmed valve surgery. PATIENTS AND METHODS A patient who underwent phacoemulsification with Ahmed valve implantation surgery had a retained Weck-Cels sponge soaked with mitomycin-C. With the use of ocular ultrasound B-Scan, the retained sponge was localized and a second procedure was performed to explant it. CONCLUSION In cases of ocular gossypiBoma the use of ultrasound modalities can Be a valuaBle tool especially Because B-Scan access is common and can Be cost-effective.
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ocular gossypiBoma ultrasound B Scan assessment of retained surgical sponge after ahmed valve surgery a case report
Journal of Glaucoma, 2017Co-Authors: Kelly Babic, Christine Siguanbell, Michael Hee, Shan C LinAbstract:PURPOSE OF THE STUDY To present the first documented case of an ocular gossypiBoma (retained foreign Body) of a mitomycin-C-soaked sponge confirmed echographically using diagnostic ultrasound B-Scan after Ahmed valve surgery. PATIENTS AND METHODS A patient who underwent phacoemulsification with Ahmed valve implantation surgery had a retained Weck-Cels sponge soaked with mitomycin-C. With the use of ocular ultrasound B-Scan, the retained sponge was localized and a second procedure was performed to explant it. CONCLUSION In cases of ocular gossypiBoma the use of ultrasound modalities can Be a valuaBle tool especially Because B-Scan access is common and can Be cost-effective.
Hiroko Terasaki - One of the best experts on this subject based on the ideXlab platform.
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diagnostic characteristics of polypoidal choroidal vasculopathy Based on B Scan swept source optical coherence tomography angiography and its interrater agreement compared with indocyanine green angiography
Retina-the Journal of Retinal and Vitreous Diseases, 2020Co-Authors: Ai Fujita, Keiko Kataoka, Jun Takeuchi, Yuyako Nakano, Etsuyo Horiguchi, Hiroki Kaneko, Yasuki Ito, Hiroko TerasakiAbstract:Purpose To examine the characteristics of polypoidal choroidal vasculopathy using B-Scan optical coherence tomography angiography (OCTA), and determine the diagnostic criteria of polypoidal choroidal vasculopathy Based on OCTA. Methods This retrospective case series included patients diagnosed with treatment-naive polypoidal choroidal vasculopathy who underwent indocyanine green angiography (ICGA) and swept-source OCTA at Baseline. We compared the characteristics of the polyps detected using B-Scan OCTA and ICGA. Then, the diagnostic concordance of each polypoidal lesion Between ICGA and OCTA was evaluated. Results Among 54 eyes of 52 patients, all 54 eyes showed flow signals indicating polyps on Both ICGA and B-Scan OCTA. All polyps on B-Scan OCTA were detected as round/ring-like flow signals inside pigment epithelial detachments, incomplete round/ring-like flow signals overlaid with round/ring-like OCT structures inside pigment epithelial detachments, or flow signals adjacent to a pigment epithelial detachment notch. Using B-Scan OCTA, 94.7% of the polypoidal lesions were detected By an independent evaluator with an overall accuracy of 92.6% for counting the polypoidal lesions per eye relative to ICGA and a Kappa value of 0.82. Conclusion Polyp detection on B-Scan OCTA demonstrates high accuracy and is comparaBle to that oBtained on ICGA. B-Scan OCTA could replace ICGA for the diagnosis of polypoidal choroidal vasculopathy.
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characteristics and classification of type 3 neovascularization with B Scan flow overlay and en face flow images of optical coherence tomography angiography
Retina-the Journal of Retinal and Vitreous Diseases, 2020Co-Authors: Keiko Kataoka, Ai Fujita, Jun Takeuchi, Yuyako Nakano, Hiroki Kaneko, Yasuki Ito, Hiroko TerasakiAbstract:Purpose:To study B-Scan flow overlay and en face flow optical coherence tomography angiography (OCT-A) images of Type 3 neovascularization (NV) and to characterize a staging system for Type 3 NV Based on the OCT-A findings.Methods:We retrospectively collected data on consecutive treatment-naive eyes
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A case of Type 2 choroidal neovascularization (CNV).
2019Co-Authors: Yuyako Nakano, Ai Fujita, Keiko Kataoka, Jun Takeuchi, Hiroki Kaneko, Yasuki Ito, Hideyuki Shimizu, Hiroko TerasakiAbstract:Left eye images of a 70-year-old female patient with a visual acuity of 20/25. (a) Mid-phase fluorescein angiography showing intense leakage and indicating a classic CNV type. (B) Indocyanine green angiography showing the neovascular vessels. (c) 3 × 3-mm en face optical coherence tomography angiography (OCTA) images after removal of projection artifacts showing the dense small vessels. (d and e) Corresponding B-Scan images showing the segmentation lines (d) and flow signals overlaid on the B-Scan image (e).
Seok Hwan Kim - One of the best experts on this subject based on the ideXlab platform.
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three dimensional evaluation of the lamina criBrosa using spectral domain optical coherence tomography in glaucoma
Investigative Ophthalmology & Visual Science, 2012Co-Authors: Eun Ji Lee, Tae Woo Kim, Robert N Weinreb, Min Hee Suh, Myungjoo Kang, Ki Ho Park, Seok Hwan KimAbstract:PURPOSE: To introduce a novel, digital, three-dimensional (3D) reconstruction of the optic nerve head (ONH) and to use this method to evaluate the 3D configuration of the lamina criBrosa (LC) in patients with primary open-angle glaucoma. METHODS: Optic discs of 137 eyes of 137 patients with open-angle glaucoma were Scanned with enhanced depth-imaging spectral domain-optical coherence tomography (SD-OCT). 3D images of the ONH were then reconstructed from B-Scan images using maximum intensity projection (MIP) and texture-Based volume rendering (VRT). The performance of the threshold segmentation By MIP and VRT was assessed By comparing the distance of the anterior LC surface from the reference line set at the Bruch's memBrane opening level (LC depth) measured within Both of the 3D images and the B-Scan images. RESULTS: The LC configuration could Be evaluated three dimensionally in ∼95% of patients Scanned with enhanced depth-imaging SD-OCT. The mean LC depth was 559.50 ± 151.98, 558.97 ± 152.39, and 560.22 ± 152.26 μm in B-Scan, MIP, and VRT images, respectively. There were excellent agreements Between the values (intraclass correlation coefficient = 1.000 Between MIP and B-Scan, and 0.999 Between VRT and B-Scan). The configuration of the LC varied consideraBly among individual glaucoma patients. CONCLUSIONS: This method provides measuraBle 3D images of the LC that enaBle comprehensive evaluation of the LC configuration. This technique should facilitate the investigation of the LC in glaucomatous eyes.