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Extensive Macular Atrophy with Pseudodrusen Imaged with OCT Angiography
摘要： This report describes the first case of extensive macular atrophy with pseudodrusen (EMAP) imaged with optical coherence tomography angiography (OCTA). A 58-year-old Caucasian man presented with decreased central vision in both eyes. Fundus examination showed large areas of macular atrophy centered on the fovea surrounded by diffuse reticular pseudodrusen. Spectral domain OCT (SDOCT) revealed outer retinal and choriocapillaris atrophy. OCTA demonstrated marked absence of choriocapillaris flow. Extensive macular atrophy with pseudodrusen is a rare clinical entity and a new extreme phenotype of macular degenerations that could shed more light on the role of pseudodrusen and choriocapillaris compromise in the pathogenesis of AMD.
关键词： macular degeneration,OCT angiography,Extensive macular atrophy,pseudodrusen
更新于2025-09-10 09:29:36
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An update on inflammatory choroidal neovascularization: epidemiology, multimodal imaging, and management
摘要： Inflammatory choroidal neovascular membranes are challenging to diagnose and manage. A number of uveitic entities may be complicated by the development of choroidal neovascularization leading to a decrease in central visual acuity. In conditions such as punctate inner choroidopathy, development of choroidal neovascularization is extremely common and must be suspected in all cases. On the other hand, in patients with conditions such as serpiginous choroiditis, and multifocal choroiditis, it may be difficult to differentiate between inflammatory choroiditis lesions and choroidal neovascularization. Multimodal imaging analysis, including the recently introduced technology of optical coherence tomography angiography, greatly aid in the diagnosis and management of inflammatory choroidal neovascularization. Management of these neovascular membranes consists of anti-vascular growth factor agents, with or without concomitant anti-inflammatory and/or corticosteroid therapy.
关键词： Posterior uveitis,angiography,Choroiditis,Uveitis,Fluorescein angiography,Optical coherence tomography angiography,EDI-OCT,Indocyanine green,Inflammatory choroidal neovascularization
更新于2025-09-09 09:28:46
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Role of OCT Angiography in the Detection of Retinal Vascular and Macular Abnormalities in Subjects with Asteroid Hyalosis
摘要： Purpose: To study the role of Optical coherence tomography (OCT) Angiography (OCTA) in detecting retinal vascular and macular abnormalities as compared to Fundus Fluorescein Angiography (FFA) in subjects with Asteroid hyalosis (AH). Methods: In a prospective study, patients with AH underwent OCTA and FFA. AH graded as Grade 1 in 8 (optic disc, second order vessels visible), Grade 2 in 4 (optic disc, first-order vessels visible), Grade 3 in 11 (hazy view of optic disc) and Grade 4 (no view of fundus) in 2 eyes. Results: A total of 20 patients (25 eyes) with AH were included. In comparison to FFA, OCTA was able to similarly detect Diabetic Retinopathy changes such as Neovascularization, microaneurysms, capillary dropout, and foveal avascular zone extent in vascular occlusion in all grades of AH. Conclusion: OCTA, a noninvasive imaging tool, could detect various retinal vascular and macular abnormalities in patients with all grades of AH in comparison to FFA.
关键词： Fundus Fluorescein Angiography (FFA),macular abnormalities,OCT angiography (OCTA),asteroid hyalosis,retinal vascular abnormalities
更新于2025-09-09 09:28:46
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Efficacy of intravitreal aflibercept monotherapy in retinopathy of prematurity evaluated by periodic fluorescence angiography and optical coherence tomography
摘要： Purpose To evaluate the efficacy of intravitreal aflibercept (IVA) in vascular and macular maturation in neonates with type 1 retinopathy of prematurity (ROP) and aggressive posterior retinopathy of prematurity (APROP). Materials and methods Thirty-six eyes of 18 patients with type 1 ROP or APROP in zone I or posterior zone II were enrolled in our study. At baseline, only fluorescein angiography (FA) was performed. After IVA injection, both FA and optical coherence tomography (OCT) were performed after 6.8 ± 0.8 (range 6–8) and 19 ± 0.9 (range 18–20) weeks to follow vascular and macular changes. Results Both diffuse flat neovascularization with leakage and abnormal vascular branching at the small arteriolar level were detected in all eyes (100%) at baseline FA. Regression of the disease was observed in 34 eyes (94.4%) in the first week with binocular indirect ophthalmoscopy. Early unresponsiveness in remaining two eyes of an infant required an IVA re-treatment. Late reactivation was detected only in 19.4% of eyes, none of which required treatment during 12 months of follow-up. The most common feature after IVA injection was abnormal branching at capillary level, which was noted in 100% in the first post-injection FA and 50.0% of all eyes in the second FA. Meanwhile, the end limit of vascularization was observed in zone III in 83.3% of eyes. No vascular abnormality was also detected in 27.3% of eyes. The OCT examination at a mean postmenstrual age of 43.4 weeks revealed cystoid macular changes in four eyes of two infants (11.1%), normal foveal contour in 30 eyes of 15 infants (83.3%) and matured ellipsoid zone at the foveal center in 28 eyes of 14 infants (77.8%). Macular maturation was complete in all eyes in the last OCT analyses. Conclusion Intravitreal aflibercept monotherapy has been an effective treatment in type I ROP and APROP with much lower early and late re-treatment rates because of early unresponsiveness and late reactivation, respectively. In most of the eyes, rapid vascular outgrowth beyond zone III together with normal macular maturation was observed more precisely by periodic FA and OCT.
关键词： Fluorescein angiography,Retinopathy of prematurity,Optical coherence tomography,Aflibercept
更新于2025-09-09 09:28:46
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Computed Tomography Imaging of the Coronary Arteries: State of the Art Applications and Recent Patents
摘要： Computed tomography (CT) is important for the management of many medical illnesses, including coronary artery disease (CAD). However this technique is not free from disadvantages like the exposure to ionizing radiations and to iodinated contrast agents. To overcome these problems, imaging technologies are changing rapidly. New-generation computed tomography scanners (NGCCT) may bring substantial advantages over traditional CT and other currently used imaging methods. These novel tools employ dedicated protocols to shorten imaging times and reduce radiation doses without affecting accuracy. Current CT scanners can very accurately identify severe CAD requiring intervention in most patients, but NGCCT may further benefit imaging for some “difficult” patients like obese patients, patients with high or irregular heart rates, and patients who have high coronary calcium burden or previous stents or bypass grafts. In fact in these patients traditional CT studies often produce suboptimal quality images. Our review presents the current status in the technical background of coronary nuclear tomographic imaging in the areas of clinical practice, and focuses on future developments of related patent forms.
关键词： Computed tomography,coronary artery disease,contrast nephrotoxicity,radiation dose,computed tomography coronary angiography,iodinated contrast medium
更新于2025-09-09 09:28:46
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Single-Breath-Hold Whole-heart Unenhanced Coronary MRA Using Multi-shot Gradient Echo EPI at 3T: Comparison with Free-breathing Turbo-field-echo Coronary MRA on Healthy Volunteers
摘要： We investigated the feasibility of single breath hold unenhanced coronary MRA using multi-shot gradient echo planar imaging (MSG-EPI) on a 3T-scanner. Methods: Fourteen volunteers underwent single breath hold coronary MRA with a MSG-EPI and free-breathing turbo field echo (TFE) coronary MRA at 3T. The acquisition time, signal to noise ratio (SNR), and the contrast of the sequences were compared with the paired t-test. Readers evaluated the image contrast, noise, sharpness, artifacts, and the overall image quality. Results: The acquisition time was 88.1% shorter for MSG-EPI than TFE (24.7 ± 2.5 vs 206.4 ± 23.1 sec, P < 0.01). The SNR was significantly higher on MSG-EPI than TFE scans (P < 0.01). There was no significant difference in the contrast on MSG-EPI and TFE scans (1.8 ± 0.3 vs 1.9 ± 0.3, P = 0.24). There was no significant difference in image contrast, image sharpness, and overall image quality between two scan techniques. The score of image noise and artifact were significantly higher on MSG-EPI than TFE scans (P < 0.05). Conclusion: The single breath hold MSG-EPI sequence is a promising technique for shortening the scan time and for preserving the image quality of unenhanced whole heart coronary MRA on a 3T scanner.
关键词： men,coronary angiography,respiration,magnetic resonance imaging
更新于2025-09-09 09:28:46
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Compton camera based on Timepix3 technology
摘要： The Compton camera concept is based on the reconstruction of recorded Compton scattering events of incoming gamma rays. The scattering of primary gamma ray occurs in the first detector (called scattering detector — usually thin) recording the position and energy of the recoiled electron. The scattered gamma quantum continues towards the second detector (called absorption detector - usually thick) where it is absorbed. The second detector records the energy and the position of this scattered gamma. Using the Compton scattering equation it is possible to determine the scattering angle, and estimate possible directions of the original gamma ray as a surface of a cone. When the Compton camera records the number of such events, the location and the shape of the gamma source can be reconstructed. Timepix3, a hybrid single photon counting imaging pixel detector, is a perfect device for creation of a compact Compton camera. Timepix3 is an event based readout chip (every hit pixel is immediately sent to a readout) and can record the time-of-arrival (ToA) and energy of an incident gamma simultaneously in each pixel. The chip offers high energy resolution (1 keV at 60 keV, 7 keV at 356 keV), as well as time resolution (1.6 ns). The Timepix3 readout chip can be combined with different sensor materials (Si, CdTe, CZT). In this contribution, we present a very compact detector system for imaging with gamma-rays using the Compton camera principle. The system consists of at least two layers of hybrid pixel detectors Timepix3 with the sensors being optimized for gamma-ray tracking. The front detector layer (scattering) is made of silicon of 1 mm thickness, while the last layer (absorbing) is equipped with thick CdTe or CZT sensors up to 2 mm in thickness. The total absorption of the whole detector can be very high if several CdTe or CZT layers are used. The maximal number of layers is not limited, but the practical evaluation was performed with 2 layers. Thanks to Timepix3 simultaneous measurement of ToA and energy, it is possible to precisely detect coincidence events in the detector layers. Based on the energy and position of these events, it is possible to estimate the possible direction of the original gamma. The angular resolution of the presented Compton camera depends on the detected energy, and it is in the order of 1 degree.
关键词： PET PET/CT,coronary CT angiography (CTA),Gamma camera,Particle tracking detectors,Compton imaging,SPECT
更新于2025-09-09 09:28:46
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Simulation and evaluation of high-performance cost-effective positron emission mammography scanner
摘要： Breast cancer is the main cause of tumor deaths in women, thus several imaging modalities have been introduced recently to better diagnose the disease. New breast cancer cases were estimated to reach up to 246,660 in 2017, and the mortality rate was above 40,000. Early diagnosis is widely approved as being essential for an e?ective treatment and it also helps to reduce the incidences and mortality rates. Positron Emission Mammography (PEM) is a breast-dedicated imaging device which uses a pair of annihilation gamma photons to detect abnormalities in the breast tissue. PEM device is compact in nature with a reduced ?eld of view to cover the entire breast region, and it employs few detector modules which makes it cost-e?cient. To e?ectively diagnose breast cancer at a very early stage, a device with high spatial resolution and high sensitivity is required. PEM detectors based on semiconductor materials are characterized by an excellent intrinsic spatial resolution but are not cost-e?ective, whereas detectors based on scintillator crystals are cost-e?ective but have limited intrinsic resolution to detect small breast lesions. This study focuses on improving the resolution of scintillator detectors by simulating a PEM scanner employing 1 × 1 × 10 mm3 laser processed scintillator crystal. The simulation was done with a GEANT4 application for emission tomography (GATE) software, and performance evaluation tests were carried out according to the National Electrical Manufacturers Association (NEMA) standards. The scanner geometry has 90 mm transaxial ?eld of view (FOV) and 105 mm axial FOV. Evaluation results showed that the scanner has 10.6% system sensitivity, 1.0 mm spatial resolution at the center of the FOV (CFOV) and at 2.5 cm transaxial direction. The resolution at the axial 2.5 cm position is 2.1 mm. NEMA image quality test and Derenzo phantom study showed that the scanner can easily resolve 1 mm in diameter hot rods.
关键词： PET PET/CT,X-ray mammography and scinto- and MRI-mammography,coronary CT angiography (CTA),Gamma camera,SPECT
更新于2025-09-09 09:28:46
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Utility of video ICG to detect the cortical entry point of a draining vein with a superficial vein during AVM surgery
摘要： Resection of brain arteriovenous malformation is challenging particularly if the feeder arteries and draining vein are not directly visible on the surface. Indocyanine green video angiography can assist detection of the connecting point of the draining vein with the superficial vein and can thus localise the cortical entry point for AVM resection. Here, we present a case of a 27-year-old man with headache. CT scan showed right occipital atypical bleeding. CTA and DSA confirmed the cortical AVM fed by the posterior cerebral artery (PCA) branches. We decided on surgical treatment because the small PCA feeders were not easily accessible for endovascular treatment. We used an OPMI PENTERO 900 microscope (Carl Zeiss, Germany) to perform microsurgical resection of AVM. We present an illustrative video showing the surgical approach, microsurgical anatomy, and technical aspects of the utility of video ICG in deep cortical small AVM surgery. Video ICG assisted detection of the cortical arterialised draining vein that was anasthamosed with a sprawled superficial vein. This enabled a customised approach for the AVM resection. Post-surgical video ICG showed normalised flow in the superficial vein supporting the complete resection of AVM. Indocyanine angiography is potentially helpful for detecting the cortical entry point of a deep draining vein with a sprawled superficial vein. ICG should be used as an adjunct to better understand the microvascular anatomy that may aid decision making during AVM surgery.
关键词： Arteriovenous malformation,Surgical treatment,Indocyanine angiography,Draining vein
更新于2025-09-09 09:28:46
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Collateral vessels on optical coherence tomography angiography in eyes with branch retinal vein occlusion
摘要： Aims To detect collateral vessels using optical coherence tomography angiography (OCTA) in eyes with branch retinal vein occlusion (BRVO) and to investigate the associations with visual outcomes and macular oedema. Methods Eyes with macular oedema secondary to BRVO that underwent OCTA at baseline and were followed up for more than 6 months were enrolled. The presence of collaterals, whether the collaterals were leaky or not, and the associations with visual outcomes and macular oedema were investigated. results Twenty-eight eyes of 28 patients (8 men and 20 women; mean age, 68 years) were enrolled. Collaterals were detected in 23 eyes (82%) and already existed at the initial visit. Collaterals were more frequently detected in eyes with major BRVO or ischaemic type. One-third of the collaterals were leaky and all of the leaky collaterals had microaneurysms (MAs) inside. Macular oedema in eyes with collaterals was more quickly and frequently resolved than that in eyes without collaterals, but there were no significant differences. Collateral vessel formation did not seem to impact on visual outcomes, but the mean baseline central retinal thickness (CRT) was significantly higher in eyes with collaterals, and the mean CRT reduction at 6 months after treatments was significantly greater than in eyes without collaterals. Conclusions These results suggest that collateral vessels are formed at the acute phase in eyes with BRVO. In addition, the presence of collaterals might be associated with absorption of macular oedema, but MAs formed in collaterals sometimes can cause macular oedema.
关键词： visual outcomes,collateral vessels,branch retinal vein occlusion,optical coherence tomography angiography,macular oedema
更新于2025-09-09 09:28:46