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The comparison of high and standard definition computed tomography techniques regarding coronary artery imaging
摘要： Object?ve: The aim was to compare coronary high-definition CT (HDCT) with standard-definition CT (SDCT) angiography as to radiation dose, image quality and accuracy. Material and methods: 28 patients with history of coronary artery disease scanned by HDCT (Discovery CT750 HD) and SDCT (Somatom Definition AS). The scan modes were both axial prospective ECG-triggered. The vessel diameters and vessel attenuation values of totally 280 measurements from 140 coronary arteries were analyzed by two experienced radiologists. All data was analyzed by intraclass correlation test. Image quality graded by motion and stair step artifacts (grade 1, poor, to grade 4, excellent), accuracy of vessel inner and outer diameters were compared between the two CT units using the independent samples t-test and Mann-Whitney U test. Results: The intraclass correlation coefficient (ICC) of measured vessel attenuation values in SDCT between the two radiologists was exceedingly good. The ICC was higher in HDCT. The radiation dose of HDCT was higher than that of SDCT. The mean tube current was 180 (mA) in HDCT and 147(mA) in SDCT with the same tube voltage (kVp). There was no significant difference between image quality. Conclusion: HDCT has a higher radiation dose but has much more atenuation and the spatial resolution which improve measurement accuracy for imaging coronary arteries.
关键词： Coronary Arteries,Computerised Tomography,Angiography
更新于2025-09-23 15:21:21
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Peripheral retinal nonperfusion using widefield imaging with von Hippel-Lindau disease
摘要： Background: To describe a case of von Hippel-Lindau disease with peripheral retinal nonperfusion. Case presentation: A 66-year-old female with known cerebellar and midbrain hemangioblastomas was evaluated for a retinal hemangioblastoma in the right eye. She underwent widefield fluorescein angiography, which showed hyperfluorescence localized to the hemangioblastoma surrounded by peripheral retinal nonperfusion in the same quadrant. Conclusions: Further widefield imaging studies are required to determine if peripheral retinal nonperfusion is a common finding in von Hippel-Lindau disease.
关键词： Nonperfusion,Tumor,Fluorescein angiography,Hemangioblastoma,von Hippel-Lindau,Eye
更新于2025-09-23 15:21:21
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Ultraweitwinkel-Fundusfotografie und -angiografie in der Differenzialdiagnose und zur Therapieplanung bei peripheren vaskul?ren Netzhauterkrankungen
摘要： Investigation of vascular diseases of the peripheral retina requires imaging procedures that allow a comprehensive view of the periphery, as well as reproducible pictures. In particular, ultra-wide field fluorescence angiography facilitates diagnosis, therapeutic decisions and follow-up examinations. While vasculopathies such as Coats disease and familiar exudative vitreoretinopathy are diagnosed within the first and second decade of life, patients? compliance during fundus imaging is typically reduced within this age range. Compared to the repeated imaging procedures for composite formation, ultra-wide field imaging has significantly reduced recording time. Nevertheless, current imaging systems are not able to map the entire retina in scaled proportions. Therefore, the imaging frame must be guided by patients? gaze onto the affected retinal area. Moreover, the medical photographer must be aware of the clinical setting and the region of interest. Hence, previous detailed funduscopy by trained ophthalmologists will remain indispensable.
关键词： ultra?wide field angiography,vasoproliferative retinal tumor,ultra?wide field imaging,coats disease,hemangioblastoma,familiar exudative vitreoretinopathy
更新于2025-09-23 15:21:21
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The Validity of Optical Coherence Tomography Angiography as a Screening Test for the Early Detection of Retinal Changes in Patients with Hydroxychloroquine Therapy
摘要： Purpose: The aim of this study was to quantitatively compare both the vessel density of macular capillary plexuses and the foveal avascular zone (FAZ) areas of patients receiving hydroxychloroquine (HCQ) therapy for more than 5 years while using age- and sex- matched controls. Methods: The patients undergoing HCQ who were screened for toxic effects were evaluated. The FAZ parameters included the area, perimeter, and the acircularity index. The foveal density and vessel density values of both the superficial (SCP) and deep capillary plexuses (DCP) were measured using optical coherence tomography angiography (OCTA). Results: This study included 80 eyes of 40 subjects: 20 subjects in the HCQ group and 20 subjects in the control group. The FAZ perimeter and the FAZ area in the SCP and full retinal vasculature were significantly larger in the HCQ group than in the control group (P < 0.05 for all). Additionally, the vessel density of fovea in the SCP and DCP was significantly lower in the HCQ group than in the control group (P < 0.05 for all). Conclusions: OCTA provides objective documentation about FAZ and vessel density features in patients using long-term HCQ therapy before toxicity begins, and it can be used as a screening tool for detecting early changes in the macula.
关键词： optical coherence tomography angiography,Chloroquine,foveal avascular zone,vessel density,hydroxychloroquine
更新于2025-09-23 15:21:21
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Comparison of OCT angiography in children with a history of intravitreal injection of ranibizumab versus laser photocoagulation for retinopathy of prematurity
摘要： Purpose To compare the foveal microvascular structure characteristics in children with a history of intravitreal injection of ranibizumab (IVR) versus laser photocoagulation (LP) for retinopathy of prematurity by optical coherence tomography angiography (OCTA). Methods In this cross- sectional study, a total of 17 children (28 eyes) underwent IVR and 20 children (37 eyes) underwent LP were recruited. The age of doing OCTA examination of the two groups are 5.4±1.1 years and 6.3±1.8 years, respectively (p=0.07). Spectral- domain OCTA was performed for all the eyes with a scan size of 3×3 mm. The data of the superficial retinal layer were analysed. The foveal avascular zone (FAZ) and vessel density (including vessel length density (VLD) and perfusion density (PD)) were measured using the software of OCTA (Cirrus AngioPlex 5000, Carl Zeiss, Meditec, Dubin, California, USA). The central foveal thicknesses (CFT) were measured by cross- sectional OCT. results In the central fovea, the retinal VLD and PD of patients with IVR were 13.82±2.99 mm/ mm2 and 0.25±0.05 mm2/mm2, respectively, which were significantly lower than those of the LP group (15.64±2.71 mm/mm2 and 0.28±0.05 mm2/mm2, p=0.01 and p=0.006). The FAZ area of patients with IVR and LP were 0.13±0.09 mm2 and 0.09±0.07 mm2, respectively (p=0.048). The CFT of patients with IVR and LP were 200.7±16.7 μm and 220.9±22.7 μm, respectively (p<0.01). The logarithm of the minimal angle of resolution best- corrected visual acuity of patients with IVR and LP were 0.2±0.1 and 0.1±0.1, respectively (p=0.01). There was no significant difference in the parafoveal and foveal VLD and PD, FAZ morphological index and spherical equivalent refraction (SER) between the two groups. Conclusion The IVR might contribute to microvascular changes in the macular zone, such as reducing the central foveal VLD and PD, while the LP might contribute to microstructural changes, such as smaller FAZ and thicker CFT.
关键词： intravitreal injection of ranibizumab,foveal microvascular structure,OCT angiography,laser photocoagulation,retinopathy of prematurity
更新于2025-09-23 15:21:01
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Technical Aspects, Interpretation, and Body of Evidence for Coronary Computed Tomography Angiography
摘要： Coronary computed tomography angiography has high sensitivity for the detection of coronary stenosis and excellent negative predictive value to rule out stenosis. Due to rapid technical developments, images of excellent quality are obtained with rare artifacts and low radiation doses. Recently established and updated guidelines provide guidance through coronary interpretation with structured and consistent reporting.
关键词： Coronary interpretation,Coronary stenosis,Coronary CT angiography,Emergency department
更新于2025-09-23 15:21:01
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Characterization of monolithic GAGG:Ce coupled to both PMT and SiPM array for gamma imaging in Nuclear Medicine
摘要： GaGG:Ce scintillation crystal is very useful for nuclear imaging purposes, thanks to its several advantages (high density, short decay time, high light yield and good energy resolution, no self-activity, no hygroscopic). However, only the recent improvements in the growth processes make it available with large size, in order to use it in monolithic configuration. The main drawbacks of pixelated crystals, as non-uniform response, high production costs and optical light loss, could be therefore overcome. In this work the characterization of this promising crystal coupled both to a single channel PMT (spectrometric purpose) and to a new technology SiPM (50% PDE and 74% geometrical fill factor) has been performed. The detection efficiency results good both for SPECT (87% at 122 keV) and for PET (18% at 356 keV) applications. However, the unexpected result arises from the energy resolution: at 356 keV 8.9% and 8.0% for single channel PMT and SiPM configuration, respectively. In other terms, the used SiPM allows to achieve higher energy resolution than single channel PMT. Moreover, a high imaging performance has been observed, with a millimeter intrinsic spatial resolution.
关键词： SPECT,PET PET/CT,Gamma camera,Intra-operative probes,Scintillators and scintillating fibres and light guides,coronary CT angiography (CTA),Scintigraphy and whole-body imaging
更新于2025-09-23 15:21:01
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Cardiac Computed Tomography 2.0
摘要： Computed tomography angiography (CTA) is now an established diagnostic option for patients with chest pain. It is a safe alternative to functional testing, provides diagnostic certainty, is a good gatekeeper for downstream invasive angiography, and increases the diagnostic yield when invasive angiography is eventually needed. CTA-driven care is associated with more relief of angina and generates optimal medical therapy associated with reduced death and myocardial infarction. However, CT angiography can lead to more cardiac catheterizations as well as more coronary revascularization. CTA shows good sensitivity, but also suffers from suboptimal specificity; thus, one cannot be sure, lacking other functional test results, that more revascularization procedures are necessary or beneficial compared to operating on lesions with demonstrated ischemia.
关键词： Fractional Flow Reserve,Myocardial Perfusion Imaging,Cardiac Computed Tomography,Coronary Artery Disease,CT Angiography
更新于2025-09-23 15:21:01
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Swept-Source Optical Coherence Tomography Angiography in Central Serous Chorioretinopathy
摘要： Purpose: This article aims to evaluate the appearance of central serous chorioretinopathy (CSC) with swept-source optical coherence tomography angiography (SS-OCTA), to discuss whether localization of the leakage spot seen on fluorescein angiography (FA) corresponds to any recognizable spot on SS-OCTA, and to provide subsequent diagnosis of choroidal neovascularization (CNV) in the course of CSC. Methods: A prospective interventional case series was conducted in a private outpatient office on 30 eyes of 27 patients. In addition to ophthalmic examination, FA, spectral-domain OCT, SS-OCT and SS-OCTA were performed at least once. If laser photocoagulation or anti-vascular endothelial growth factor (anti-VEGF) injection was administered, then all examinations were repeated afterward. Following SS-OCTA, morphology features of CSC were analyzed: localization of the leakage spot, presence of feeder vessels, and presence of CNV. Changes after treatment were recorded. Results: In 26 of 30 cases the leakage site on FA corresponded to a highly hyporeflective site on SS-OCTA. In 7 of these cases laser was successfully administered. In 20/30 eyes we additionally observed thickened vessels at the level of choriocapillaris in close proximity to the most hyporeflective spot. CNV was observed in 4 cases. The leakage spot is the most hyporeflective spot on SS-OCTA localized at the level of choriocapillaris. Additionally, choroidal feeder vessels might be visualized at the level of choriocapillaris in 66% of cases. In 4 eyes, CNV in the course of CSC was noted. Conclusions: In CSC, SS-OCTA is a valuable diagnostic tool and its results complement FA. It might add to the treatment process, especially regarding the need to start and to monitor anti-VEGF injections. Anti-VEGF treatment results in fading but not in complete disappearance of CNV in the course of CSC.
关键词： central serous chorioretinopathy,swept-source OCT angiography,anti-VEGF,laser
更新于2025-09-23 15:21:01
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Simultaneous Investigation of Vascular and Retinal Pigment Epithelial Pathologies of Exudative Macular Diseases by Multifunctional Optical Coherence Tomography
摘要： To investigate exudative macular disease, multifunctional optical coherence tomography (MF-OCT) using a 1-lm probe band was developed. The clinical utility of MF-OCT was examined in a descriptive case series. METHODS. Ten eyes of nine subjects with exudative macular disease, including one eye with age-related macular degeneration (AMD), one eye with idiopathic neovascular maculopathy, and eight eyes with polypoidal choroidal vasculopathy (PCV), were investigated. Areas of 6 3 6 mm2 around the pathologic region were scanned with 512 3 1024 depth scans in 6.6 seconds. Structural OCT, Doppler optical coherence angiography (OCA), and cumulative phase retardation images were obtained with a single measurement. Each MF-OCT image visualized the structure, vasculature, and birefringence. Degree of polarization uniformity values were also obtained for selective visualization of the retinal pigment epithelium (RPE). The MF-OCT images were compared with conventional ophthalmic images. RESULTS. Abnormal vasculatures were observed with Doppler OCA in all eyes, which presented high similarity to indocyanine green angiography in the midphase. The RPE and exudation in the pathologic regions were discriminated in one eye with AMD and ?ve of eight eyes with PCV. Cumulative phase retardation visualized ?brosis scars in two of the PCV cases. CONCLUSIONS. Multifunctional OCT revealed depth-resolved abnormal vasculatures, the integrity of the RPE and choroid, discrimination of the RPE and exudation, and existence of ?brosis scars in exudative macular diseases. Interpretation of MF-OCT examination is well matched with conventional ophthalmic examination. These results suggest that MF-OCT can be used as a noninvasive ophthalmic examination tool prior to conventional examinations in clinical routines.
关键词： polarization-sensitive OCT,OCT angiography,optical coherence tomography,retinal pigment epithelium,exudative macular disease
更新于2025-09-23 15:21:01