Design of an endoscopic OCT probe based on piezoelectric tube with quartered outside electrodes.

Introduction: Optical coherence tomography (OCT) is a pivotal imaging modality in ophthalmology for real-time, in vivo visualization of retinal structures. To enhance the capability and safety of OCT, this study focuses on the development of a micro intraocular OCT probe. The demand for minimal invasiveness and precise imaging drives the need for advanced probe designs that can access tight and sensitive areas, such as the ocular sclera. Methods: A novel OCT probe was engineered using a piezoelectric tube with quartered electrodes to drive Lissajous scanning movements at the end of a single-mode fiber. This design allows the probe to enter the eyeball through a scleral opening. Structural innovation enables the outer diameter of the endoscopic OCT probe to be adjusted from 13G (2.41 mm) to 25G (0.51 mm), accommodating various imaging field sizes and ensuring compatibility with different scleral incisions. Results: The fabricated micro intraocular OCT probe successfully performed preliminary imaging experiments on in vivo fingers. The Lissajous scanning facilitated comprehensive coverage of the target area, enhancing the imaging capabilities. Discussion: The integration of a piezoelectric tube with quartered outside electrodes into the OCT probe design proved effective for achieving precise control over scanning movements and adaptability to different surgical needs. The design characteristics and practical applications demonstrated the probe's potential in clinical settings.

Impact of Combined Nifedipine and Aspirin Therapy on Hemodynamics in Patients with Early Eclampsia.

Background: Preeclampsia poses substantial risks during pregnancy. Exploring innovative treatment approaches like the combination of Nifedipine and aspirin is crucial for improving maternal and fetal outcomes. Objective: This study aims to assess the efficacy of nifedipine and aspirin tablets in treating preeclampsia and their impact on blood rheology and coagulation. Methods: We selected 96 pregnant patients with preeclampsia treated at our hospital between January 2020 and January 2022. The patients were randomly assigned to either the research group (n=48) or the control group (n=48). Nifedipine was administered to the control group, while the research group received a combination of Nifedipine and aspirin. We compared the overall treatment effectiveness and the incidence of unfavorable pregnancy outcomes between the two groups. Results: The research group exhibited a significantly higher overall treatment effectiveness rate (93.75%) compared to the control group (P < .05). After treatment, levels of fibrinogen (FIB), whole high-cut blood viscosity (HBV), whole low-cut blood viscosity (LBV), plasma viscosity (PV), and erythrocyte rigidity index (HGX) were significantly lower in the study group than in the control group (P < .05). Additionally, plasminogen time (PT) and activated partial thromboplastin time (APTT) were higher in the research group compared to the control group (P < .05). The research group also experienced a lower frequency of negative pregnancy outcomes (4.17%) in contrast to the control group (18.75%) (P < .05). Conclusions: The nifedipine and aspirin combination effectively treats pregnancy hypertension, enhancing both coagulation and hemorheology for improved maternal and fetal health outcomes.

Predicting potential distribution of the Rhinoncus sibiricus under climatic in China using MaxEnt.

In recent years, buckwheat (Fagopyrum spp.) is being increasingly damaged by the Siberian tortoise beetle (Rhinoncus sibiricus Faust). Adults and nymphs feed on leaf tissues and caulicles, thus damaging its stems and leaves. In this study, we investigated the habits, distribution, and environmental impact of R. sibiricus using MaxEnt, an ecological niche model. Geographic information about the infestation site from previous field surveys and climatic data from 2013 to 2018 were organized and optimized using R. The impact factors were calculated using MaxEnt software. The results indicate that population fluctuations in R. sibiricus are related to changes in temperature, humidity, and their spatial distribution. Under current climatic conditions, R. sibiricus is mainly distributed in northern China, with sporadic distribution in south-western China. The values for a survival probability threshold > 0.3 were: precipitation during the wettest month (bio13), 70.31-137.56 mm; mean temperature of the coldest quarter (bio11), -15.00-0.85°C; mean temperature of the warmest quarter (bio10), 11.88-23.16°C; precipitation during the coldest quarter (biol9), 0-24.39 mm. The main factors contributing > 70% to the models were precipitation during the wettest month and coldest quarter, and mean temperature during the warmest and coldest quarters. Under both future climate models, the center of the fitness zone moves northward. Our results will be useful in guiding administrative decisions and support farmers interested in establishing control and management strategies for R. sibiricus. This study could also serve as a reference for future research on other invasive pests.

Infection-specific transcriptional patterns of the maize pathogen Cochliobolus heterostrophus unravel genes involved in asexual development and virulence.

Southern corn leaf blight (SCLB) caused by Cochliobolus heterostrophus is a destructive disease that threatens global maize (Zea mays) production. Despite many studies being conducted, very little is known about molecular processes employed by the pathogen during infection. There is a need to understand the fungal arms strategy and identify novel functional genes as targets for fungicide development. Transcriptome analysis based on RNA sequencing was carried out across conidia germination and host infection by C. heterostrophus. The present study revealed major changes in C. heterostrophus gene expression during host infection. Several differentially expressed genes (DEGs) induced during C. heterostrophus infection could be involved in the biosynthesis of secondary metabolites, peroxisome, energy metabolism, amino acid degradation and oxidative phosphorylation. In addition, histone acetyltransferase, secreted proteins, peroxisomal proteins, NADPH oxidase and transcription factors were selected for further functional validation. Here, we demonstrated that histone acetyltransferases (Hat2 and Rtt109), secreted proteins (Cel61A and Mep1), peroxisomal proteins (Pex11A and Pex14), NADPH oxidases (NoxA, NoxD and NoxR) and transcription factors (Crz1 and MtfA) play essential roles in C. heterostrophus conidiation, stress adaption and virulence. Taken together, our study revealed major changes in gene expression associated with C. heterostrophus infection and identified a diverse repertoire of genes critical for successful infection.

The histidine kinases regulate allyl-isothiocyanate sensitivity in Cochliobolus heterostrophus.

BACKGROUD: Two-component histidine kinase (HK) phosphorelay signaling systems play important roles in differentiation, virulence, secondary metabolite production and response to environmental signals. Allyl isothiocyanate (A-ITC) is a hydrolysis product of glucosinolates with excellent antifungal activity. Our previous study indicated that the mycelial growth of Cochliobolus heterostrophus was significantly hindered by A-ITC. However, the function of HK in regulating A-ITC sensitivity was not clear in C. heterostrophus, the causal agent of Southern corn leaf blight. RESULTS: In this study, the role of HKs was investigated in C. heterostrophus. Deletion of the HK coding gene ChNIK1 resulted in dramatically increased sensitivity of C. heterostrophus to A-ITC. In addition, ΔChnik1 mutant exhibited significantly decreased conidiation and increased sensitivity to NaCl, KCl, tebuconazole and azoxystrobin, but deletion of the other five HK genes did not affect the A-ITC sensitivity of C. heterostrophus. ChSLN1, ChNIK4, ChNIK8 and ChMAK2 are essential for conidiation and response to H2 O2 and sodium dodecyl sulfate. However, deletion of NIKs had on effect on significant virulence. CONCLUSION: Our findings demonstrate that the HKs play different roles in A-ITC sensitivity in C. heterostrophus. © 2023 Society of Chemical Industry.

Design of a Subretinal Injection Robot Based on the RCM Mechanism.

This study presents an investigation focusing on the advancement of a robot designed for subretinal injections in the context of macular degeneration treatment. The technique of subretinal injection surgery stands as the most efficacious approach for the successful transplantation of stem cells into the retinal pigment epithelium layer. This particular procedure holds immense significance in advancing research and implementing therapeutic strategies involving retinal stem cell transplantation. The execution of artificial subretinal surgery poses considerable challenges which can be effectively addressed through the utilization of subretinal injection surgery robots. The development process involved a comprehensive modeling phase, integrating computer-aided design (CAD) and finite element analysis (FEA) techniques. These simulations facilitated iterative enhancements of the mechanical aspects pertaining to the robotic arm. Furthermore, MATLAB was employed to simulate and visualize the robot's workspace, and independent verification was conducted to ascertain the range of motion for each degree of freedom.

Crucial Roles of the High-Osmolarity Glycerol Pathway in the Antifungal Activity of Isothiocyanates against Cochliobolus heterostrophus.

Isothiocyanates (ITCs) that are found in Brassicaceae exhibited obvious antifungal activity against Cochliobolus heterostrophus, which is the causal agent of southern corn leaf blight. However, the underlying antifungal mechanism of allyl-ITCs (A-ITCs) against C. heterostrophus remains largely unknown. Here, we used transcriptomic analysis to find that the high osmolarity pathway was upregulated significantly when treated with A-ITCs. To investigate the roles of the high osmolarity pathway in adaption to A-ITCs, we constructed Δssk2, Δpbs2, and Δhog1 mutant strains. Deletion of three genes (ChSSK2, ChPBS2, and ChHOG1) involved in the high osmolarity pathway resulted in significantly increased sensitivity of C. heterostrophus to ITCs. In addition, the phosphorylation level of ChHog1 was induced by A-ITC and was dependent on the presence of ChSsk2 and ChPbs2. Moreover, Δssk2, Δpbs2, and Δhog1 mutants exhibited a dramatically decreased virulence on maize leaves. Our findings demonstrated that the high osmolarity pathway played a positive role in ITC tolerance and virulence, which may provide novel insights into developing ITCs as a new fungicide against C. heterostrophus.

Physical compensation method for dispersion of multiple materials in swept source optical coherence tomography.

An ophthalmic swept source-optical coherence tomography (SS-OCT) system based on a high-speed scanning laser at 1060 nm with a scanning rate of 100 KHz is constructed. Since the sample arm of the interferometer is comprised of multiple glass materials, the ensuing dispersion severely degrades imaging quality. In this article, second-order dispersion simulation analysis for various materials was performed first, and dispersion equilibrium was implemented utilizing physical compensation methods. After dispersion compensation, an imaging depth in air of 4.013 mm was achieved in model eye experiments, and signal-to-noise ratio was enhanced by 11.6%, with a value of 53.8 dB. In vivo imaging of the human retina was performed to demonstrate structurally distinguishable retinal images, characterized by an axial resolution improvement of 19.8%, with a value of 7.7 µm close to the theoretical value of 7.5 µm. The proposed physical dispersion compensation method enhances imaging performance in SS-OCT systems, enabling visualization of several low scattering mediums.

Challenging deep learning models with image distortion based on the abutting grating illusion.

Even state-of-the-art deep learning models lack fundamental abilities compared with humans. While many image distortions have been proposed to compare deep learning with humans, they depend on mathematical transformations instead of human cognitive functions. Here, we propose an image distortion based on the abutting grating illusion, which is a phenomenon discovered in humans and animals. The distortion generates illusory contour perception using line gratings abutting each other. We applied the method to MNIST, high-resolution MNIST, and "16-class-ImageNet" silhouettes. Many models, including models trained from scratch and 109 models pretrained with ImageNet or various data augmentation techniques, were tested. Our results show that abutting grating distortion is challenging even for state-of-the-art deep learning models. We discovered that DeepAugment models outperformed other pretrained models. Visualization of early layers indicates that better-performing models exhibit the endstopping property, which is consistent with neuroscience discoveries. Twenty-four human subjects classified distorted samples to validate the distortion.

Scleral Suture Intraocular Lens Fixation Under Microscope-Intraoperative Optical Coherence Tomography.

PURPOSE: The aim of this study was to evaluate the accessibility and potential value of intraoperative optical coherence tomography (iOCT) during scleral suture intraocular lens (IOL) fixation. METHODS: This was a prospective cohort study in the Department of Ophthalmology, Eye and ENT Hospital, Fudan University, China. Seven eyes with insufficient capsular support and undergoing two-point scleral suture IOL fixation were included. The potential value of iOCT was evaluated, as well as the safety and efficacy of the surgery. RESULTS: Seven eyes were included. With a tailor-made iOCT, the structure of the anterior segment could be clearly visualized during the surgery. Intraoperatively, iOCT helped locate the proper place for fixation and access the position of the IOL. After an average 4.43-month follow-up, the spherical equivalent changed significantly ( P < 0.001), but the intraocular pressure, best-corrected visual acuity, and endothelial cell density remained unchanged ( P > 0.05). The IOL was well-centered with a horizontal and a vertical tilt of 0.74 ± 0.60° and 1.13 ± 0.65°, and decentration of 0.28 ± 0.12 mm and 0.30 ± 0.13 mm. The estimated IOL-induced astigmatism was -0.11 diopters (D) ± 0.46 D. CONCLUSION: Real-time high-resolution images of the anterior segment acquired by the iOCT helped the surgeon to achieve satisfactory results in scleral suture IOL fixation.

Numerical simulation flow dynamics of an intracranial aneurysm.

BACKGROUND: Computational fluid dynamics provides a new method for the study of the blood flow characteristics of the formation and development of intracranial aneurysms. OBJECTIVE: To compare blood flow characteristics between the healthy internal carotid artery and normal intracranial aneurysms. METHODS: The internal carotid arteries were simulated to obtain hemodynamic parameters in one patient. RESULTS: The internal carotid artery associated with aneurysm presents low wall shear stress, high oscillatory shear index, and high particle retention time compared with the normal internal carotid artery. CONCLUSIONS: There are differences in blood flow between the normal internal carotid artery and intracranial aneurysm. The vortex of the aneurysm will produce turbulence, indicating that it is unstable, which results in the growth and rupture of the aneurysm.

Microscope integrated optical coherence tomography system combined with augmented reality.

One of the disadvantages in microscope-integrated optical coherence tomography (MI-OCT) systems is that medical images acquired via different modalities are usually displayed independently. Hence, surgeons have to match two-dimensional and three-dimensional images of the same operative region subjectively. In this paper, we propose a simple registration method to overcome this problem by using guided laser points. This method combines augmented reality with an existing MI-OCT system. The basis of our idea is to introduce a guiding laser into the system, which allows us to identify fiducials in microscopic images. At first, the applied voltages of the scanning galvanometer mirror are used to calculate the fiducials' coordinates in an OCT model. After gathering data at the corresponding points' coordinates, the homography matrix and camera parameters are used to superimpose a reconstructed model on microscopic images. After performing experiments with artificial and animal eyes, we successfully obtain two-dimensional microscopic images of scanning regions with depth information. Moreover, the registration error is 0.04 mm, which is within the limits of medical and surgical errors. Our proposed method could have many potential applications in ophthalmic procedures.

LAMB1 Is Related to the T Stage and Indicates Poor Prognosis in Gastric Cancer.

BACKGROUND AND OBJECTIVE: Gastric cancer (GC) is a common tumor malignancy with high incidence and poor prognosis. Laminin is an indispensable component of basement membrane and extracellular matrix, which is responsible for bridging the internal and external environment of cells and transmitting signals. This study mainly explored the association of the LAMB1 expression with clinicopathological characteristics and prognosis in gastric cancer. METHODS: The expression data and clinical information of gastric cancer patients were downloaded from The Cancer Genome Atlas (TCGA) and Asian Cancer Research Group (ACRG). And we analyzed the relationship between LAMB1 expression and clinical characteristics through R. CIBERSORTx was used to calculate the absolute score of immune cells in gastric tumor tissues. Then COX proportional hazard models and Kaplan-Meier curves were performed to evaluate the role of LAMB1 and its influence on prognosis in gastric cancer patients. Finally, GO and KEGG analysis were applied for LAMB1-related genes in gastric cancer, and PPI network was constructed in Cytoscape software. RESULTS: In the TCGA cohort, patients with gastric cancer frequently generated LAMB1 gene copy number variation, but had little effect on mRNA expression. Both in the TCGA and ACRG cohorts, the mRNA expression of LAMB1 in gastric cancer tissues was higher than it in normal tissues. All patients were divided into high expression group and low expression group according to the median expression level of LAMB1. The elevated expression group obviously had more advanced cases and higher infiltration levels of M2 macrophages. COX proportional hazard models and Kaplan-Meier curves revealed that patients with enhanced expression of LAMB1 have a worse prognosis. GO/KEGG analysis showed that LAMB1-related genes were enriched in PI3K-Akt signaling pathway, focal adhesion, ECM-receptor interaction, etc. CONCLUSIONS: The high expression of LAMB1 in gastric cancer is related to the poor prognosis of patients, and it may be related to microenvironmental changes in tumors.

Real-time measurement of repetitive micro bulk motion vector and motion noise removal in optical coherence tomography angiography.

In this work, we developed a motion estimation and correction method which real-time obtained the direction and displacement of repetitive micro bulk motion (such as cardiac and respiratory motion) on an SS-OCT system without additional tracking hardware, and reduced the motion noise in optical coherence tomography angiography (OCTA). In the approach, the direction of repetitive micro bulk motion was considered fixed, and proportional relationships between the motion components in three directions were determined; Then we performed one-dimension cross-correlation to obtain depth displacement which was further used to obtain other two motion components, and greatly reduced the computation; The processing speed on a graphic processing unit was 478 pairs of B-Scans per second, and the measurement range was larger than the range of the angiogram-based methods. Lastly, corrupt angiograms were recovered by adaptive scan protocol, and reduced acquisition time in comparison with the previous work.

Microscope-integrated Intraoperative Optical Coherence Tomography for Anterior Segment Surgical Maneuvers.

Purpose: To evaluate the potential value of microscope-integrated optical coherence tomography (MI-OCT) in anterior segment surgical maneuvers. Methods: Twenty-four ophthalmology residents, who were randomly and evenly divided into two groups, performed four anterior segment surgical maneuvers (corneal tunnel, scleral tunnel, simple corneal suture, and corneal laceration repair) on porcine eyes with (group B) or without (group A) real-time MI-OCT feedback. All residents performed the maneuvers again without MI-OCT. Results: Compared with group A, group B (with MI-OCT) showed better accuracy in the length/depth of the corneal tunnel and the length of the scleral tunnel. However, both groups showed similar performances in the depth of both the simple corneal suture and the corneal laceration suture. When both groups performed the maneuvers again without MI-OCT, group B still showed better results than group A for the length of both the corneal and scleral tunnels. Conclusions: Primary results suggest that real-time MI-OCT images are valuable for some anterior segment surgical maneuvers and could be helpful in surgical training. Translational Relevance: MI-OCT systems can be valuable in improving accuracy and decision making during anterior segment surgery and will be useful in surgical training.

Interplane bulk motion analysis and removal based on normalized cross-correlation in optical coherence tomography angiography.

Bulk motion seriously degrades the image quality of optical coherence tomography angiography (OCTA). Conventional correction methods focus on in-plane displacement, while the bulk motion component perpendicular to B-scans also introduces noise. This work first presents an evaluation of this component using a specific scan protocol and an approximate expression derived from peak-normalized cross-correlation values, and then quantitatively assesses how interplane bulk motion noise reduce the sensitivity of cross-sectional angiograms. Finally, we developed a repetitive bulk motion correction method based on the estimated displacements and redundant volume scans. The correction does not require registration and angiogram reconstruction of low flow sensitivity frames, and the results of in vivo mice skin OCTA imaging experiments show that the proposed method can effectively reduce bulk motion noise caused by cardiac and respiratory motion and occasional shaking, and improve OCTA image quality, which has practical significance for clinical OCTA diagnosis and analysis.

Feasibility of microscope-integrated swept-source optical coherence tomography in canaloplasty.

BACKGROUND: Several researchers have used commercial microscope-integrated optical coherence tomography (OCT) systems in glaucoma surgery, including ab interno trabeculectomy and canaloplasty. However, the 840 nm wavelength light source of the OCT systems is not ideal for imaging the anterior chamber angle structures because of its limited penetration. We evaluated the potential value of a microscope-integrated swept-source OCT system with a 1,310 nm center-wavelength light in canaloplasty for glaucoma. METHODS: Sixteen porcine eyes were used to simulate canaloplasty. The critical surgical steps were monitored using a prototype microscope-integrated OCT system with a 1,310 nm light source and a high axial scan rate of 100 kHz. The images from swept-source OCT and three-dimensional images from the microscope were projected simultaneously onto a liquid crystal display three-dimensional monitor (LMD-4251TD, Sony, Japan). The changes in the collector vessel (aqueous drainage structure in the porcine eye, similar to Schlemm's canal in humans) were measured using Image J software. Histological sections stained with hematoxylin and eosin were used to assess surgical efficacy. RESULTS: High-resolution real-time images of the anterior segment were acquired during canaloplasty using the microscope-integrated OCT system. With the real-time OCT images, the position of the collector vessel was identified and the scleral flap could be created at the ideal location. The expansion of the collector vessel after viscoelastic injection was also visualized in real time. Compared with baseline, there was a significant increase in the cross-sectional area (from 14,502.98±9,242.55 to 59,499.04±20,506.41 µm2, P<0.001) of the collector vessel. CONCLUSIONS: Using the microscope-integrated OCT system, real-time images of the anterior segment were successfully acquired during the operation. The microscope-integrated OCT system might be useful in future anti-glaucoma surgery.

Older people living with human immunodeficiency virus/acquired immune deficiency syndrome in Chinese rural areas: perceived stigma and associated factors.

BACKGROUND: Perceived stigma is a common problem among people living with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) (PLWHA). In recent years, the number of older adults with HIV/AIDS has rapidly increased in China. However, HIV/AIDS-related perceived stigma and associated factors in older PLWHA remain unknown. METHODS: A cross-sectional study was conducted in Yongzhou. Participants were recruited via the Hunan HIV/AIDS Registry system. All participants were ≥50 y of age at the time of their HIV diagnosis. Sowell's HIV Stigma Scale was used to measure perceived stigma. RESULTS: A total of 193 participants were interviewed, of which 132 (68.4%) were male. The ages of the participants ranged from 50 to 82 y and the average age was 61.1±5.95 y. Eighteen (9.3%) subjects were ethnic minorities. Older PLWHA reported a relatively high level of perceived stigma, especially individuals of Han ethnicity having high annual incomes. The individuals who had disclosed their HIV-positive status to all their family had higher scores on the dimension related to blame. Regression analysis showed that ethnicity, annual income, living arrangement and disclosure patterns were the main associated factors of perceived stigma. CONCLUSIONS: Perceived stigma is common in older Chinese PLWHA. Individuals of ethnic minorities or with higher economic status have higher levels of stigma. Family relationships have a deep influence on perceived stigma.

Generation and Characterization of Induced Pluripotent Stem Cells from Mononuclear Cells in Schizophrenic Patients.

OBJECTIVE: Schizophrenia (SZ) is a mental disorder in which psychotic symptoms are the main problem. The pathogenesis of SZ is not fully understood, partly because of limitations in current disease models and technology. The development of induced pluripotent stem cell (iPSC) technology has opened up the possibility of elucidating disease mechanisms in neurodegenerative diseases. Here, we aimed to obtain iPSCs from peripheral blood mononuclear cells (PBMCs) of normal and schizophrenic individuals and analyze the inflammatory response in these iPSCs. MATERIALS AND METHODS: In this experimental study, we isolated PBMCs from whole blood of healthy individuals and SZ patients and reprogrammed them into iPSCs by transfection of recombinant lentiviruses that contained Yamanaka factors (Oct4, Sox2, Klf4 and c-Myc). We calculated the numbers of iPSC clones and stained them with alkaline phosphatase (ALP), Nanog, SSEA4, Nestin, Vimentin, and AFP to confirm their efficiency and pluripotency. The iPSCs were analyzed by real-time quantitative polymerase chain reaction (qRT-PCR) for the expressions of inflammatory factors. RESULTS: iPSCs from schizophrenic patients (SZ-iPSCs) exhibited typical morphology and highly expressed pluripotent markers. These iPSCs retained their normal karyotype and differentiated in vitro to form embryoid bodies (EBs) that expressed markers of all 3 germ layers. However, iPSCs from the SZ-iPSCs group had a weak capacity to differentiate into ectoderm compared to the normal iPSCs (Con-iPSC). An elevated, stronger inflammatory response existed in iPSCs from schizophrenic individuals. CONCLUSION: We successfully obtained iPSCs from PBMCs of schizophrenic patients without genetic operation and analyzed the expressions of pluripotent markers and inflammatory factors between the Con-iPSC and SZ-iPSC groups. Taken together, our results may assist to explain the pathogenesis of SZ and develop new strategies for clinical diagnosis and treatment.

Gemstone spectral imaging reduced artefacts from metal coils or clips after treatment of cerebral aneurysms: a retrospective study of 35 patients.

OBJECTIVE: This study aimed to evaluate the effect of gemstone spectral imaging (GSI) for metal artefact reduction in cerebral artery CT angiography (CTA) after metal coils or clips treatment. METHODS: 35 patients with cerebral aneurysms were treated with metal coils or clips and underwent CTA using gemstone spectral CT between February and December 2013. The data were reconstructed into three image groups including Group A (quality check images with 140 kVp), Group B (monochromatic image sets in the range of 40-140 keV) and Group C [monochromatic image sets with metal artefacts reduction software (MARS GE Medical Systems, Waukesha, WI)]. CT attenuation value of cerebral artery, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and the subjective score of all images were measured and compared statistically. RESULTS: CT attenuation value of cerebral artery decreased in Groups B and C as the photon energy increased. The average energy levels of 60.05 ± 5.37 and 59.93 ± 5.57 keV presented the best CNR in Groups B and C, respectively. CNR values, SNR values and the subjective scores of the image quality of the two sets were higher than those of Group A. CONCLUSION: GSI reduced metal artefact and improved the image quality of CTA after metal coils or clips treatment in patients with cerebral aneurysm. The monochromatic images at the average energy level of 60.05 ± 5.37 keV with MARS and 59.93 ± 5.57 keV without MARS were suggested to be the optimal parameters. ADVANCES IN KNOWLEDGE: GSI could reduce metal artefact after metal coils or clips treatment in patients with cerebral aneurysm.