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Advances in imaging and molecular diagnostics of ocular tuberculosis and selected observations from the Collaborative Ocular Tuberculosis Study (COTS)
摘要： Introduction: Ocular tuberculosis (TB) is a rare extra-pulmonary manifestation with protean clinical manifestations. Ocular TB as a cause of potentially blinding disease has been recently recognized by ophthalmologists as well as pulmonologists. In the past decade, there has been a great leap in our understanding of the disease pathogenesis, clinical and imaging features, as well as therapeutic challenges and disease complications. Areas covered: In this expert review, an emphasis has been laid on the recent advances in ocular imaging including wide-field fundus imaging, fluorescein angiography and autofluorescence, enhanced-depth optical coherence tomography, optical coherence tomography angiography, among others, as well as progress in the field of diagnostics such as polymerase chain reaction and other nucleic acid amplification tests. Findings from the Collaborative Ocular Tuberculosis Study (COTS), a multicentric study on ocular TB, have been explained in details. Expert opinion: Due to rapid advances in the field of fundus imaging and laboratory testing, it has become possible to recognize the pathological alterations observed in ocular TB. With further research, it may be possible to generate a consensus on the diagnosis and management of this entity in the future.
关键词： Tuberculosis,optical coherence tomography,choroiditis,fluorescein angiography,serpiginous-like choroiditis,indocyanine green angiography,uveitis
更新于2025-09-23 15:23:52
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Small HDL subclass is associated with coronary plaque stability: An optical coherence tomography study in patients with coronary artery disease
摘要： BACKGROUND: The role of high-density lipoprotein (HDL) subclasses in atherosclerotic diseases remains an open question. Previous clinical trials have attempted to explore the predictive effect of HDL subspecies on cardiovascular risk. However, no studies have assessed the connections between these subclasses and characteristics of plaque microstructure. OBJECTIVE: To investigate the relationship of HDL subclasses and coronary plaque stability assessed by optical coherence tomography (OCT). METHODS: Morphological characteristics of 160 nontarget lesions from 85 patients with coronary artery disease were assessed by OCT. HDL subclass profiles were analyzed using nondenaturing polyacrylamide gel electrophoresis. RESULTS: The plasma levels of small HDL subclass (percentage or concentration) were found to be positively associated with fibrous cap thickness (r = 0.232, P = .007; r = 0.243, P = .005) and negatively with maximum lipid arc (r = -0.240, P = .005; r = -0.252, P = .003) and lipid core length (r = -0.350, P < .001; r = -0.367, P < .001). Multivariate logistic regression analysis showed the small HDL subclass (percentage or concentration) (odds ratio [OR]: 0.457, 95% confidence interval [CI]: 0.214–0.974, P = .043; OR: 0.438, 95% CI: 0.204–0.938, P = .034) to be an independent factor in predicting OCT-detected thin-cap fibroatheroma of nontarget lesions. CONCLUSION: High levels of small HDL are associated with coronary nontarget plaque stability. Our findings suggest that the small HDL subtype might represent the atheroprotective activity of HDL.
关键词： Atherosclerosis,High-density lipoprotein,Optical coherence tomography,Plaque stability
更新于2025-09-23 15:23:52
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Implementation of multiphase computed tomography angiography in management of patients with acute ischemic stroke in clinical practice
摘要： Multiphase computed tomography angiography (CTA) provides information on the status of major cranial arteries and extent of brain collateralization. The purpose of the study was to determine whether implementation of multiphase CTA in routine clinical practice was feasible, safe and useful. Patients with acute ischemic stroke (NIHSS (cid:1) 6) were included. Multiphase CTA was performed. Duration of performing multiphase CTA, inter-rater correlation and incidence of contrast-induced nephropathy (CIN) were studied. Infarct volume, incidence of hemorrhagic transformation, the rates of favorable outcome and death were compared between those with poor and intermediate-good collateralization. Multiphase CTA was performed in 108 patients. Mean duration on each multiphase CTA study was 4.8 min. Inter-rater reliability was intermediate-good (weighted kappa 0.7569, p < 0.001). CIN occurred in 3 patients (2.8%). There were no major intracranial/extracranial artery occlusion in 31 patients (29%) and there were severe stenosis or occlusions in 77 patients (71%). In the subgroup of patients with major artery severe stenosis or occlusion, 36 patients (36/77, 47%) had poor collateralization. Despite non-signi?cant difference in acute treatment, the patients with poor collateralization had larger infarct (123 vs 35 cc, p < 0.001) and poorer outcomes (mean modi?ed Rankin scale 3.86 vs 2.73, p = 0.011), while the differences in symptomatic hemorrhagic transformation (2.6 vs 7%, p = 0.385) and death rate (14 vs 12%, p = 0.825) were non-signi?cant, as compared to those with intermediate-good collateralization. Multiphase CTA was feasible and safe. Besides the status of major arteries, multiphase CTA provided information on collateralization, which was associated with the size of infarct and clinical outcomes.
关键词： Multiphase CTA,Asian,Thai,Acute stroke,Computed tomography angiography,Ischemic stroke
更新于2025-09-23 15:23:52
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Development of simultaneous PET and Compton imaging using GAGG-SiPM based pixel detectors
摘要： Positron emission tomography (PET) is considered an important and powerful tool for molecular imaging and medical diagnosis with its high sensitivity. Further, single-photon emission CT (SPECT) is another important imaging modality providing different types of information in medical diagnosis. On the other hand, Compton imaging is a promising technique for future molecular imaging with multi-nuclides based on Compton scattering kinetics. In this regard, previously, we have developed gadolinium aluminum gallium garnet (GAGG)-scintillation-based PET systems and GAGG-scintillation-based Compton imaging systems for environmental applications. Here, we propose and develop a novel PET–Compton hybrid simultaneous imager based on a two-layer structure using thin scatterers and thick absorbers for multi-nuclide imaging, for e.g., simultaneous imaging of PET and SPECT tracers such as 18F-FDG and 111In, respectively. For achieving good spatial resolution of the Compton imager, the energy resolution of the utilized scintillators forms one of the most important characteristics. In this regard, GAGG is a promising scintillator because of its high light yield of over 50 000 photon/MeV and excellent energy resolution of 4% with no background radiation and moderate decay time. In this study, we present the development of a simultaneous PET–Compton detector that consists of an 8 × 8 multi-pixel photon counter/SiPM (MPPC) array individually coupled with a 2.5 × 2.5 × 9-mm3 Ce:Gd3Ga2.7Al2.3O12 scintillators (absorbers) for proof of concept of simultaneous PET and SPECT imaging. The pixel size of the MPPC is 3 mm × 3 mm, and it is operated at 55 V at room temperature. The signals from the MPPC scintillators are individually amplified and converted with a dynamic time over threshold (dTOT) circuit to record the energy and timing information. In image reconstruction, the data acquired with the use of the developed modules are classified into events of either Compton imaging or PET imaging by coincidence detection between scatterer and absorber or between absorber and absorber, respectively. The coincidence events between absorber and absorber are regarded as PET annihilation-gamma events and those between scatterer and absorber are used as Compton imaging events. In our experiment, images of 111In and 18F-FDG, which are used as multi-nuclide tracers, are acquired simultaneously using the developed detector for Compton imaging and PET imaging. We believe that our approach is a significant step forward for medical imaging and related fields.
关键词： Scintillator,Single-photon emission CT,SiPM,Positron emission tomography,Compton imaging
更新于2025-09-23 15:23:52
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Axial Fourier Rebinning for Time-of-Flight PET
摘要： Fully 3D time-of-flight (TOF) PET scanners offer the potential of substantially improved image quality in clinical PET imaging. The main challenges of 3D TOF PET imaging are the data storage with either list-mode or binned formats, and the reconstruction time using iterative algorithms. Previously, we derived the Fourier rebinning and consistency equations (FORCEs), and showed 3D TOF data can be fully characterized by two consistency equations. In this work, we present an exact Fourier rebinning for 3D TOF data based on the axial consistency equation to dramatically reduce the data storage and the reconstruction time. Starting from pre-corrected 3D TOF data, the axial Fourier rebinning algorithm estimates a 2D TOF sinogram for each transverse slice without information loss. Since the 3D TOF data are axially truncated, we provide a solution to estimate the missing portion in the oblique TOF projection data. The proposed axial Fourier rebinning for TOF data (axFRT) can take advantage of all the 3D TOF data statistics, and the rebinned 2D TOF data can then be reconstructed using any algorithms for 2D or 2.5D TOF reconstructions. The axFRT algorithm allows the axial data sets being rebinned independently, and there are tens of thousands of such data sets which can naturally take advantage of the massively parallel processors to dramatically speedup the rebinning. We show numerical simulations to demonstrate that axFRT produces accurate and unbiased rebinned sinograms even for TOF PET with large axial acceptance angle. The axFRT will be particularly useful for 3D TOF PET with large axial field of view for PET imaging applications including dynamic, whole- or total-body imaging.
关键词： image reconstruction,positron emission tomography (PET),time-of-flight,Axial Fourier rebinning
更新于2025-09-23 15:23:52
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Relationship between retinal vessel diameter with both retinal nerve fibre layer thickness and optic nerve head parameters in middle‐aged Caucasians: the Northern Finland Birth Cohort Eye study
摘要： Purpose: To study the normal relationship between retinal vessel diameter (RVD) with retinal nerve fibre layer (RNFL) thickness and optic nerve head (ONH) parameters in a cohort of middle-aged Caucasians. Methods: We investigated 3070 individuals (6140 eyes). Central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were measured in the right eye using a semi-automated computer-assisted program. Retinal nerve fibre layer (RNFL) thickness and ONH parameters were assessed with Heidelberg retinal tomography (HRT). Results: Data from 2217 persons were analysed including RNFL, CRAE, CRVE, sex, body mass index, mean arterial pressure, diabetes status, smoking status, optic disc area, rim area, spherical refraction and intraocular pressure. A larger RVD was associated with a thicker mean global RNFL thickness especially in global and inferior segments of the retina and with larger optic discs. Each 10 lm increase in the retinal arteriolar calibre was associated with a 5.58 lm increase in mean global RNFL thickness; the corresponding value for a 10 lm increase in venular calibre was 3.79 lm (p < 0.001 for both). Retinal venular calibre displayed consistent associations with RNFL thickness in both genders (p < 0.001 for all), whereas the association of arteriolar calibre and RNFL was more prominent in men (p < 0.001). Conclusion: We found strong associations between larger RVD and thicker RNFL in all subjects. This study helps to clarify the association between RVD, RNFL thickness and ONH parameters and provides normal values for middle-aged Caucasians that will help in future studies investigating the role of vascular aetiology in systemic and eye diseases.
关键词： optic nerve head,retina,IVAN,Heidelberg retinal tomography,central retinal venular equivalent,central retinal arteriolar equivalent
更新于2025-09-23 15:23:52
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Current Status of Patient Radiation Exposure of Cardiac Positron Emission Tomography and Single-Photon Emission Computed Tomographic Myocardial Perfusion Imaging
摘要： BACKGROUND: Radiation exposure during nuclear cardiology procedures has received much attention and has prompted citations for radiation reduction. In 2010, the American Society of Nuclear Cardiology recommended reducing the average patient study radiation exposure to <9 mSv in 50% of studies by 2014. Cardiac positron emission tomography (PET) for myocardial perfusion imaging (MPI) has emerged within recent years, but current radiation exposure in cardiac nuclear PET laboratories is unknown. This study evaluated current reported patient radiation exposure from nuclear laboratories in the United States applying for Intersocietal Accreditation Commission accreditation for MPI using single photon emission computed tomography (SPECT) or PET. METHODS AND RESULTS: This was an analysis of nuclear cardiology studies submitted to the Intersocietal Accreditation Commission for either or both cardiac PET and SPECT accreditation. Cardiac SPECT data represented year 2015 while PET data combined years 2013 to 2015. Data was analyzed with χ2 and Mann-Whitney U tests (reported as median, 25th percentile, and 75th percentile). Reported PET MPI radiation exposure for 111 laboratories (532 patient cases) was 3.7 (3.2–4.1) mSv per study with no geographic variation. Reported SPECT MPI radiation exposure for 665 laboratories (3067 patient studies) was 12.8 (12.2–14.3) mSv. Highest radiation exposure was found in the South region. Technetium-only studies resulted in a median of 12.2 mSv per study. CONCLUSIONS: Radiation exposure from cardiac PET MPI in US laboratories applying for Intersocietal Accreditation Commission accreditation is low (111 laboratories, 3.7 mSv) and substantially lower than cardiac SPECT (665 laboratories, 12.8 mSv).
关键词： technetium,accreditation,myocardial perfusion imaging,positron emission tomography,radiation exposure
更新于2025-09-23 15:23:52
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Spectral-domain optical coherence tomography foveal morphology as a prognostic factor for vision performance in congenital aniridia
摘要： Background: Patients with congenital aniridia usually have some degree of foveal hypoplasia, thus representing a limiting factor in the final visual acuity achieved by these patients. The purpose of this study was to analyze whether the foveal morphology assessed by spectral-domain optical coherence tomography may serve as a prognostic indicator for best-corrected visual acuity in congenital aniridia patients. Methods: Observational two-center study performed between January 2012 and March 2017 in the pediatric ophthalmology department at Vissum Alicante and Vissum Madrid, Spain. A total of 31 eyes from 19 patients with congenital aniridia were included. After a complete ophthalmological examination, a high-resolution spectral-domain optical coherence tomography with a three-dimensional scan program macular protocol was used. A morphological grading system of foveal hypoplasia was used varying from grade 1 in which there is a presence of a shallow foveal pit, extrusion of inner retinal layers, outer nuclear layer widening, and a presence of outer segment lengthening to grade 4 in which none of these processes occur. Results: No correlation between central, mid-peripheral, and peripheral macular thickness and logMAR best-corrected visual acuity was found. The presence of outer segment lengthening was associated with better best-corrected visual acuity with a median best-corrected visual acuity, 0.30 logMAR, whereas the absence of this morphologic feature was associated with poorer VA with a median best-corrected visual acuity of 0.61 logMAR (p < 0.001). Conclusion: Foveal hypoplasia morphology can predict the best-corrected visual acuity. Specifically, the morphologic optical coherence tomography feature that is related to a better best-corrected visual acuity in congenital aniridia patients is the presence of outer segment lengthening.
关键词： Congenital aniridia,spectral-domain optical coherence tomography,foveal hypoplasia
更新于2025-09-23 15:23:52
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Quantitative measurement of vascular density and flow using optical coherence tomography angiography (OCTA) in patients with central retinal vein occlusion: Can OCTA help in distinguishing ischemic from non-ischemic type?
摘要： Background: To evaluate microvascular changes and quantitative parameters in patients with central retinal vein occlusion (CRVO) by using optical coherence tomography angiography (OCTA) and finding difference between presumably ischemic and non ischemic CRVO. Methods: Patients with CRVO (31) and healthy control (20) were enrolled in this observational case control study. The OCTA was done for each patient and control subject. In macular area 2 images were taken for each eye (3 × 3 mm and 8 × 8 mm). The images were analyzed at three capillary plexuses (superficial and deep retinal capillary layers and choriocapillaris layer). Results: Thirty-one patients with CRVO (mean age 60.00 ± 13.72 years) and 20 healthy age/gender matched subjects (mean age 54.10 ± 12.33 years) were enrolled in this study (p = 0.095). The mean visual acuity of patients was 0.47 ± 0.54 LogMAR. Eyes with CRVO as compared with fellow eyes and control group showed significant reduction of flow in superficial (1.171 ± 0.262 vs. 1.362 ± 0.285 vs. 1.453 ± 0.105) and deep capillary plexus (1.042 ± 0.402 vs. 1.331 ± 0.315 vs. 1.526 ± 0.123) and choriocapillaris (1.206 ± 0.543 vs. 1.841 ± 0.308 vs. 1.966 ± 0.05) and vascular density in superficial (45.92 ± 4.2 vs. 50.99 ± 4.35 vs. 52.85 ± 2.99) and deep (48.03 ± 4.71 vs. 55.86 ± 3.81 vs. 58.2 ± 2.65) capillary plexuses. Some parameters (flow of both retinal capillary plexuses and parafoveal vascular density in deep plexus) showed significantly reduction in fellow eyes than control group. The parameters including flow [superficial (1.014 ± 0.264 vs. 1.279 ± 0.19) and deep (0.873 ± 0.442 vs. 1.152 ± 0.32) capillary plexuses and choriocapillaris (0.79 ± 0.327 vs. 1.424 ± 0.51)] and vascular density [superficial (44.24 ± 2.13 vs. 46.58 ± 4.13) and deep (45.28 ± 3.5 vs. 49.32 ± 3.94) capillary plexuses] were lower significantly in ischemic type than non ischemic CRVO. The most damaged parameter was flow in deep capillary plexus. The model with smallest Akaike information criterion and Bayesian information criterion was chosen as the best model. For easier calculation, we also calculated the reduced model. By choosing the threshold of 12.6, the formula [3.9 × F1S + 0.8 × F3S] can diagnose the presumably ischemic CRVO from non ischemic type with AUC of 0.84, sensitivity of 100% and specificity of 69%. (F1S: flow in the central 1 mm-radius-circle of superficial plexus and F3S: flow in the central 3 mm-radius-circle of superficial plexus). Conclusion and relevance: In CRVO patients, the OCTA can accurately evaluate changes in microvascular structures. It may help in differentiation ischemic CRVO from non-ischemic CRVO.
关键词： Ischemic,Non-ischemic,Central retinal vein occlusion,Optical coherence tomography angiography
更新于2025-09-23 15:23:52
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Readjustment of abdominal computed tomography protocols in a university hospital: impact on radiation dose
摘要： Objective: To assess the reduction of estimated radiation dose in abdominal computed tomography following the implementation of new scan protocols on the basis of clinical suspicion and of adjusted images acquisition parameters. Materials and Methods: Retrospective and prospective review of reports on radiation dose from abdominal CT scans performed three months before (group A – 551 studies) and three months after (group B – 788 studies) implementation of new scan protocols proposed as a function of clinical indications. Also, the images acquisition parameters were adjusted to reduce the radiation dose at each scan phase. The groups were compared for mean number of acquisition phases, mean CTDIvol per phase, mean DLP per phase, and mean DLP per scan. Results: A significant reduction was observed for group B as regards all the analyzed aspects, as follows: 33.9%, 25.0%, 27.0% and 52.5%, respectively for number of acquisition phases, CTDIvol per phase, DLP per phase and DLP per scan (p < 0.001). Conclusion: The rational use of abdominal computed tomography scan phases based on the clinical suspicion in conjunction with the adjusted images acquisition parameters allows for a 50% reduction in the radiation dose from abdominal computed tomography scans.
关键词： Contrast media,Radiation dose,Radiation protection,Computed tomography,Abdomen
更新于2025-09-23 15:23:52