Head Scans Research Articles

Periprocedural Cerebral Air Embolism; A Rare and Potentially Fatal Complication of Watchman Device (P3-5.028)

<h3>Objective:</h3> To study peri-procedural complications of Watchman device placement. <h3>Background:</h3> Left atrial appendage therapy with a Watchman device is a non-inferior ischemic stroke prevention strategy for patients with paroxysmal atrial fibrillation (pAF) deemed to be unsuitable for conventional anticoagulation. Peri-procedural air embolism is a known complication and can present with systemic emboli provoking ischemic strokes, coronary ischemia, or cardiac arrest. The PROTECT AF trial specifically documented 5 peri-procedural strokes out of 542 total procedures due to air embolism. We present two cases of periprocedural cerebral emboli resulting in potentially fatal complications. <h3>Design/Methods:</h3> Retrospective review of electronic medical records. <h3>Results:</h3> 81year old gentleman was noted to have acute change of decreased generalized responsiveness, and concomitant electrocardiographic change during Watchman deployment. Rapid reversal of anesthetic agents did not result in clinical improvement. Neurological exam showed asymmetric pupils, L&gt;R, and initially withdrew on all four extremities with rapid progression to flexor posturing to noxious stimulus. CT stroke protocol demonstrated an area of acute infarction in the right middle cerebral artery territory, associated with air in sulci. He required transfer to another facility for hyperbaric oxygen treatment. Follow up CT scan of head demonstrated complete resolution of air emboli, however his neurologic exam remained poor, and patient expired during hospital admission. <h3>Case 2:</h3> 61year old gentleman presented with periprocedural acute onset of right gaze deviation, left facial droop, left sided paralysis, sustained clonus, and left sensory deficit. CT stroke protocol showed hypodensity in the right MCA territory with air in sulci. He was transferred for hyperbaric oxygen therapy. After protracted rehabilitation, he lives independently with residual left sided weakness. <h3>Conclusions:</h3> Air embolism remains an under-recognized potentially fatal complication of Watchman device placement. These cases indicate the need to recognize air emboli as an etiology of periprocedural stroke requiring a unique treatment strategy including a framework for expedited hyperbaric access. <b>Disclosure:</b> Dr. Peshwe has nothing to disclose. Dr. Munir has nothing to disclose. Dr. Hatfield has nothing to disclose. The institution of an immediate family member of Dr. Adcock has received research support from NIH.

High resolution imaging with focused kV x-rays for small animal radio-neuromodulation.

High precision radiotherapy with small irradiator size has potential in many treatment applications involving small shallow targets, with small animal radio-neuromodulation as an intriguing example. A focused kV technique based on novel usage of polycapillary x-ray lenses can focus x-ray beams to <0.2mm in diameter, which is ideal for such uses. Such an application also requires high resolution CT images for treatment planning and setup. In this work, we demonstrate the feasibility of using a virtual focal spot generated with an x-ray lens to perform high-resolution CBCT acquisition. The experiment with x-ray lens was set up on an x-ray tabletop system to generate a virtual focal spot. The flood field images with and without the x-ray lens were first compared. A pinhole image was acquired for the virtual focal spot and compared with the one acquired with the conventional focal spot without the lens. The planar imaging resolution with and without the lens were evaluated using a line pair resolution phantom. The spatial resolution of the two settings were estimated by reconstructing a 0.15-mm wire phantom and comparing its full width half maximum (FWHM). A CBCT scan of a rodent head was also acquired to further demonstrate the improved resolution using the x-ray lens. The proposed imaging setup with x-ray lens had a limited exposure area of 5cm by 5cm on the detector, which was suitable for guiding radio-neuromodulation to a small target in rodent brain. Compared to conventional imaging acquisition with a measured x-ray focal spot of 0.395mm FWHM, the virtual focal spot size was measured at 0.175mm. The reduction in focal spot size with lens leads to an almost doubled planar imaging resolution and a 26% enhancement in 3D spatial resolution. A realistic CBCT acquisition of a rodent head mimicked the imaging acquisition step for radio-neuromodulation and further showed the improved visualization for fine structures. This work demonstrated that the focused kV x-ray technique was capable of generating small focal spot size of <0.2mm, which substantially improved x-ray imaging resolution for small animal imaging.

Under Pressure: Lamina Cribrosa Pore Path Tortuosity in Response to Acute Pressure Modulation.

Lamina cribrosa (LC) deformation is hypothesized to play a major role in glaucoma pathogenesis. The purpose of this study was to determine in vivo how varying intraocular pressure (IOP) under fixed intracranial pressure (ICP), and vice versa, deforms the pore paths throughout the LC volume. Spectral-domain optical coherence tomography scans of the optic nerve head were acquired from healthy adult rhesus monkeys under different pressures. IOP and ICP were controlled with gravity-based perfusion systems into the anterior chamber and lateral ventricle, respectively. IOP and ICP were modulated from baseline to high (19-30 mmHg) and highest (35-50 mmHg) levels while maintaining a fixed ICP of 8 to 12 mmHg and IOP of 15 mmHg, respectively. After three-dimensional registration and segmentation, the paths of pores visible in all settings were tracked based on their geometric centroids. Pore path tortuosity was defined as the measured distance divided by the minimal distance between the most anterior and posterior centroids. The median pore tortuosity at baseline varied among the eyes (range, 1.16-1.68). For the IOP effect under fixed ICP (six eyes, five animals), two eyes showed statistically significant increased tortuosity and one showed a decrease (P < 0.05, mixed-effects model). No significant change was detected in three eyes. When modulating ICP under fixed IOP (five eyes, four animals), a similar response pattern was detected. Baseline pore tortuosity and the response to acute pressure increase vary substantially across eyes. LC pore path tortuosity could be associated with glaucoma susceptibility.

Diagnostic yield, safety, and outcomes of Head-to-pelvis sudden death CT imaging in post arrest care: The CT FIRST cohort study

AimOur aim was to test whether a head-to-pelvis CT scan improves diagnostic yield and speed to identify causes for out of hospital circulatory arrest (OHCA). MethodsCT FIRST was a prospective observational pre-/post-cohort study of patients successfully resuscitated from OHCA. Inclusion criteria included unknown cause for arrest, age >18 years, stability to undergo CT, and no known cardiomyopathy or obstructive coronary artery disease. A head-to-pelvis sudden death CT (SDCT) scan within 6 hours of hospital arrival was added to the standard of care for patients resuscitated from OHCA (post-cohort) and compared to standard of care (SOC) alone (pre-cohort). The primary outcome was SDCT diagnostic yield. Secondary outcomes included time to identifying OHCA cause and time-critical diagnoses, SDCT safety, and survival to hospital discharge. ResultsBaseline characteristics between the SDCT (N = 104) and the SOC (N = 143) cohorts were similar. CT scans (either head, chest, and/or abdomen) were ordered in 74 (52%) of SOC patients. Adding SDCT scanning identified 92% of causes for arrest compared to 75% (SOC-cohort; p value < 0.001) and reduced the time to diagnosis by 78% (SDCT 3.1 hours, SOC alone 14.1 hours, p < 0.0001). Identification of critical diagnoses was similar between cohorts, but SDCT reduced delayed (>6 hours) identification of critical diagnoses by 81% (p < 0.001). SDCT safety endpoints were similar including acute kidney injury. Patient survival to discharge was similar between cohorts. DiscussionSDCT scanning early after OHCA resuscitation safely improved the efficiency and diagnostic yield for causes of arrest compared to the standard of care alone.Clinical Trials Number: NCT03111043.

Ordering Eyeglasses Using 3D Head Scan Technology versus Established Online and Storefront Clinic Methods.

This study investigates how a new smartphone scanning technology compares with established online and storefront vendors in providing remote measurement and adjustment of prescription eyeglasses. This study aimed to evaluate a new technology for ordering prescription eyeglasses online. Thirty participants with 2.00 to 2.75 D of presbyopia (aged 49 to 74 years) were asked to order eyeglasses with progressive addition lenses from four vendors: one online vendor using a new head scan technology (Topology, San Francisco, CA), two established Web site-based vendors (vendors A and B), and one storefront vendor: Université de Montréal's Vision Clinic (UMVC). The resulting measurements were compared with those of opticians. Participant-reported preferences on visual and physical comfort of eyeglasses were collected after 15-minute trials of eyeglasses from each vendor. Pupillary half-distance measured with Topology matched optician measurements, but online vendors A and B diverged (mean difference, - 0.80 mm [ Z = -2.79; P = .005]). Topology and vendor B segment addition heights were similar to optician measurements, but vendor A diverged (mean, -1.40 mm [ Z = -2.58; P = .01]). The personalization parameter values obtained with Topology were different from optician measurements for pantoscopic angle (-5.30° [ Z = -4.12; P < .001]) and face wrap angle (+1.25° [ Z = -2.94; P = .003]). The UMVC eyeglasses scored best for adjustment (8.71/10 [ Z = -5.53; P < .001]), with Topology coming second (7.23/10). Topology scores were equivalent to UMVC scores for all eight items of patient-reported preferences (nonparametric Friedman analysis of variance, P < .05). Basic lens centration measurements obtained with Topology compare well with those of opticians, but some aspects of the methodology for measuring personalization parameters could be improved. In comparison with two established online vendors, resulting measurements with Topology are more consistent. Initial wearer satisfaction with Topology eyeglasses was also better.

Orbital Foraminal Morphometrics in Nonsyndromic Unilateral Coronal Craniosynostosis.

Nonsyndromic unilateral coronal craniosynostosis (UCS) is a rare congenital disorder that results from premature fusion of either coronal suture. The result is growth restriction across the suture, between the ipsilateral frontal and parietal bones, leading to bony dysmorphogenesis affecting the calvarium, orbit, and skull base. Prior studies have reported associations between UCS and visual abnormalities. The present study utilizes a novel geometric morphometric analysis to compare dimensions of orbital foramina on synostotic versus nonsynostotic sides in patients with UCS. Computed tomography head scans of pediatric UCS patients were converted into 3-dimensional mesh models. Anatomical borders of left and right orbital structures were plotted by a single trained team member. Dimensions between synostotic and nonsynostotic sides were measured and compared. Medical records were examined to determine prevalence of visual abnormalities in this patient cohort. Visual abnormalities were reported in 22 of the 27 UCS patients (77.8%). Astigmatism (66.7%), anisometropic amblyopia (44.4%), and motor nerve palsies (33.3%) represented the 3 most prevalent ophthalmologic abnormalities. Orbits on synostotic sides were 11.3% narrower ( P < 0.001) with 21.2% less volume ( P = 0.028) than orbits on nonsynostotic sides. However, average widths, circumferences, and areas were similar between synostotic and nonsynostotic sides upon comparison of supraorbital foramina, infraorbital foramina, optic foramina, and foramina ovalia. Therefore, previously proposed compression or distortion of vital neurovascular structures within bony orbital foramina does not seem to be a likely etiology of visual abnormalities in UCS patients. Future studies will examine the role of ocular and/or neuro-ophthalmologic pathology in this disease process.

Deep Learning for Head and Neck CT Angiography: Stenosis and Plaque Classification.

Background Studies have rarely investigated stenosis detection from head and neck CT angiography scans because accurate interpretation is time consuming and labor intensive. Purpose To develop an automated convolutional neural network-based method for accurate stenosis detection and plaque classification in head and neck CT angiography images and compare its performance with that of radiologists. Materials and Methods A deep learning (DL) algorithm was constructed and trained with use of head and neck CT angiography images that were collected retrospectively from four tertiary hospitals between March 2020 and July 2021. CT scans were partitioned into training, validation, and independent test sets at a ratio of 7:2:1. An independent test set of CT angiography scans was collected prospectively between October 2021 and December 2021 in one of the four tertiary centers. Stenosis grade categories were as follows: mild stenosis (<50%), moderate stenosis (50%-69%), severe stenosis (70%-99%), and occlusion (100%). The stenosis diagnosis and plaque classification of the algorithm were compared with the ground truth of consensus by two radiologists (with more than 10 years of experience). The performance of the models was analyzed in terms of accuracy, sensitivity, specificity, and areas under the receiver operating characteristic curve. Results There were 3266 patients (mean age ± SD, 62 years ± 12; 2096 men) evaluated. The consistency between radiologists and the DL-assisted algorithm on plaque classification was 85.6% (320 of 374 cases [95% CI: 83.2, 88.6]) on a per-vessel basis. Moreover, the artificial intelligence model assisted in visual assessment, such as increasing confidence in the degree of stenosis. This reduced the time needed for diagnosis and report writing of radiologists from 28.8 minutes ± 5.6 to 12.4 minutes ± 2.0 (P < .001). Conclusion A deep learning algorithm for head and neck CT angiography interpretation accurately determined vessel stenosis and plaque classification and had equivalent diagnostic performance when compared with experienced radiologists. © RSNA, 2023 Supplemental material is available for this article.

Dual-Energy Computed Tomography in Stroke Imaging

ObjectiveTo assess if a new dual-energy computed tomography (DECT) technique enables an improved visualization of ischemic brain tissue after mechanical thrombectomy in acute stroke patients.Material and MethodsThe DECT head scans with a new sequential technique (TwinSpiral DECT) were performed in 41 patients with ischemic stroke after endovascular thrombectomy and were retrospectively included. Standard mixed and virtual non-contrast (VNC) images were reconstructed. Infarct visibility and image noise were assessed qualitatively by two readers using a 4-point Likert scale. Quantitative Hounsfield units (HU) were used to assess density differences of ischemic brain tissue versus healthy tissue on the non-affected contralateral hemisphere.ResultsInfarct visibility was significantly better in VNC compared to mixed images for both readers R1 (VNC: median 1 (range 1–3), mixed: median 2 (range 1–4), p < 0.05) and R2 (VNC: median 2 (range 1–3), mixed: 2 (range 1–4), p < 0.05). Qualitative image noise was significantly higher in VNC compared to mixed images for both readers R1 (VNC: median 3, mixed: 2) and R2 (VNC: median 2, mixed: 1, p < 0.05, each). Mean HU were significantly different between the infarcted tissue and the reference healthy brain tissue on the contralateral hemisphere in VNC (infarct 24 ± 3) and mixed images (infarct 33 ± 5, p < 0.05, each). The mean HU difference between ischemia and reference in VNC images (mean 8 ± 3) was significantly higher (p < 0.05) compared to the mean HU difference in mixed images (mean 5 ± 4).ConclusionTwinSpiral DECT allows an improved qualitative and quantitative visualization of ischemic brain tissue in ischemic stroke patients after endovascular treatment.

Less is more: balancing noise reduction and data retention in fMRI with data-driven scrubbing

Functional MRI (fMRI) data may be contaminated by artifacts arising from a myriad of sources, including subject head motion, respiration, heartbeat, scanner drift, and thermal noise. These artifacts cause deviations from common distributional assumptions, introduce spatial and temporal outliers, and reduce the signal-to-noise ratio of the data—all of which can have negative consequences for the accuracy and power of downstream statistical analysis. Scrubbing is a technique for excluding fMRI volumes thought to be contaminated by artifacts and generally comes in two flavors. Motion scrubbing based on subject head motion-derived measures is popular but suffers from a number of drawbacks, among them the need to choose a threshold, a lack of generalizability to multiband acquisitions, and high rates of censoring of individual volumes and entire subjects. Alternatively, data-driven scrubbing methods like DVARS are based on observed noise in the processed fMRI timeseries and may avoid some of these issues. Here we propose “projection scrubbing”, a novel data-driven scrubbing method based on a statistical outlier detection framework and strategic dimension reduction, including independent component analysis (ICA), to isolate artifactual variation. We undertake a comprehensive comparison of motion scrubbing with data-driven projection scrubbing and DVARS. We argue that an appropriate metric for the success of scrubbing is maximal data retention subject to reasonable performance on typical benchmarks such as the validity, reliability, and identifiability of functional connectivity. We find that stringent motion scrubbing yields worsened validity, worsened reliability, and produced small improvements to fingerprinting. Meanwhile, data-driven scrubbing methods tend to yield greater improvements to fingerprinting while not generally worsening validity or reliability. Importantly, however, data-driven scrubbing excludes a fraction of the number of volumes or entire sessions compared to motion scrubbing. The ability of data-driven fMRI scrubbing to improve data retention without negatively impacting the quality of downstream analysis has major implications for sample sizes in population neuroscience research.

The diagnostic value of quantitative parameters on dual-layer detector-based spectral CT in identifying ischaemic stroke.

To investigate the diagnostic value of quantitative parameters of spectral computed tomography (CT) in ischaemic stroke areas. The medical records of 57 patients with acute ischaemic stroke (AIS) who underwent plain computed tomography (CT) head scans, CT angiography (CTA), and CT perfusion (CTP) were retrospectively reviewed. The ischaemic areas (including the core infarct area and penumbra) and non-ischaemic areas in each patient were quantitatively analyzed using F-STROKE software. Two independent readers measured the corresponding values of the spectroscopic quantitative parameters (effective atomic number [Zeff value], iodine density value, and iodine-no-water value) in the ischaemic area and contralateral normal area alone. The differences in spectroscopic quantitative parameters between the two groups were compared, and their diagnostic efficacy was obtained. The Zeff, iodine-no-water value, and iodine density value of the ischaemic area all showed significant lower than those of non-ischaemic tissue (P < 0.001). For differentiating the ischaemic area from non-ischaemic tissue, the area under the curve (AUC) of the Zeff value reached 0.869 (cut-off value: 7.385; sensitivity: 93.0%; specificity: 70.2%), the AUC of the iodine density value reached 0.932 (cut-off value: 0.235; sensitivity: 91.2%; specificity: 82.5%), and the AUC of the iodine-no-water value reached 0.922 (cut-off value: 0.205; sensitivity: 96.5%; specificity: 78.9%). The study showed the spectral CT would be a potential novel rapid method for identifying AIS. The spectral CT quantitative parameters (Zeff, iodine density values, and iodine-no-water values) can effectively differentiate the ischaemic area from non-ischaemic tissue in stroke patients.

Medical Application of Geometric Deep Learning for the Diagnosis of Glaucoma.

(1) To assess the performance of geometric deep learning in diagnosing glaucoma from a single optical coherence tomography (OCT) scan of the optic nerve head and (2) to compare its performance to that obtained with a three-dimensional (3D) convolutional neural network (CNN), and with a gold-standard parameter, namely, the retinal nerve fiber layer (RNFL) thickness. Scans of the optic nerve head were acquired with OCT for 477 glaucoma and 2296 nonglaucoma subjects. All volumes were automatically segmented using deep learning to identify seven major neural and connective tissues. Each optic nerve head was then represented as a 3D point cloud with approximately 1000 points. Geometric deep learning (PointNet) was then used to provide a glaucoma diagnosis from a single 3D point cloud. The performance of our approach (reported using the area under the curve [AUC]) was compared with that obtained with a 3D CNN, and with the RNFL thickness. PointNet was able to provide a robust glaucoma diagnosis solely from a 3D point cloud (AUC = 0.95 ± 0.01).The performance of PointNet was superior to that obtained with a 3D CNN (AUC = 0.87 ± 0.02 [raw OCT images] and 0.91 ± 0.02 [segmented OCT images]) and with that obtained from RNFL thickness alone (AUC = 0.80 ± 0.03). We provide a proof of principle for the application of geometric deep learning in glaucoma. Our technique requires significantly less information as input to perform better than a 3D CNN, and with an AUC superior to that obtained from RNFL thickness. Geometric deep learning may help us to improve and simplify diagnosis and prognosis applications in glaucoma.

Establishment of national diagnostic dose reference levels (DRLs) for routine computed tomography examinations in Jordan

Abstract Background: Dose reference levels (DRLs) are used as indicators as well as guidance for dose optimization and to ensure justification of appropriate dose for a given clinical indication. The main aims of this study were to establish local DRLs for each CT imaging protocol as a reference point to evaluate the radiation dose indices and to compare our DRLs with those established in other countries and against the internationally reported guidelines. Materials and methods: 2000 CT dose reports of different adult imaging protocols from January 2021 until April 2022 were collected retrospectively at different hospitals in Jordan. Data were collected from CT scans that were performed using different types and models of CT scanners and included four adult non-enhanced, helical CT imaging protocols; Head, Chest, Abdomen-Pelvis, and Chest-Abdomen-Pelvis. Results: The average doses of CTDIvol, DLP, and effective dose were (65.11 mGy, 1232.71 mGy·cm, 2.83 mSv) for the head scan, (16.6 mGy, 586.6 mGy·cm, 8.21 mSv) for the chest scan, (17.91 mGy, 929.9 mGy·cm, 13.9 mSv) for the abdomen-pelvis scan, and (19.3 mGy, 1152 mGy·cm, 17.25 mSv) for the chest-abdomen-pelvis scan. In comparison with results from different international studies, DLP values measured in the present study were lower for the chest-abdomen-pelvis and abdomen-pelvis CT scans, and higher for the head CT and chest CT scans. Conclusions: It is very important that each country establishes its own DRLs and compares them with those reported by other countries, especially the developed ones. It is also important that these levels are regularly updated.

Automated Detection of Lesions in Patients with Traumatic Brain Injury using Brain CT Images: Concept Note and Proposed Method

AbstractAccurate and early interpretation of CT scan images in TBI patients reduces the critical time for diagnosis and management. As mentioned in other studies, automated CT interpretation using the feature extraction method is a rapid and accurate tool. Despite several studies on the machine and deep learning employing algorithms for automated CT interpretations, it has its challenges. This study presents a concept note and proposes a feature-based computer-aided diagnostic method to perform automated CT interpretation in TBI. The method consists of preprocessing, segmentation, and extraction. We have described a simple way of classifying the CT scan head into five circumferential zones in this method. The zones are identified quickly based on the anatomic characteristics and specific pathologies that affect each zone. Then, we have provided an overview of different pathologies affecting each of these zones. Utilizing these zones for automated CT interpretation will also be a helpful resource for concerned physicians during the odd and rush hours.

CORRELATION OF SIZE AND VOLUME OF CT SCAN LESION WITH SYSTEMIC INFLAMMATORY RESPONSE IN ACUTE CEREBROVASCULAR ACCIDENTS

Background Acute cerebrovascular accidents (CVA) are the leading cause of mortality and morbidity worldwide. CVA is now considered to produce an inammatory response in brain and periphery in form of rise in inammatory markers. CT scan head is an initial investigation of choice in acute cerebrovascular accidents (stroke). This study was done to correlate the size and volume of CT scan head lesion with inammatory response in acute cerebrovascular accidents. Methods Study was conducted in 90 patients of acute CVA admitted in LLR and associated hospitals, G.S.V.M. medical college Kanpur. All patients of CVA (stroke) fullling the Inclusion and exclusion criteria were enrolled in the study. CT scan head was done as an initial investigation to conrm the diagnosis. To assess the inammatory response Serum CRP (hs-CRP) level was measured by Turbidimetric immunoassay. Statistical analysis was done by using T test and chi square test. Results Our patients were mostly in the age group of 40-79 years with mean age 59 year with male predominance. CRP levels were found to be elevated statistically signicant in all types of CVA patients as compared to controls. There was signicant rise from rst day to third day (P&lt;0.05). CRP was maximum in patients of cerebral infarction as compared to other types of stroke. Observation showed higher CRP level in patients with larger lesion in CT head. Mean CRP of expired patients was higher as compared to whole study group (P&lt;0.05). Conclusions We concluded that CRP level was much elevated with increase in size and volume of lesion in CT head in patients of CVA indicating the magnitude of inammatory response, assessing severity and outcome

Geometric Deep Learning to Identify the Critical 3D Structural Features of the Optic Nerve Head for Glaucoma Diagnosis

To compare the performance of 2 relatively recent geometric deep learning techniques in diagnosing glaucoma from a single optical coherence tomographic (OCT) scan of the optic nerve head (ONH); and to identify the 3-dimensional (3D) structural features of the ONH that are critical for the diagnosis of glaucoma. Comparison and evaluation of deep learning diagnostic algorithms. In this study, we included a total of 2247 nonglaucoma and 2259 glaucoma scans from 1725 participants. All participants had their ONHs imaged in 3D with Spectralis OCT. All OCT scans were automatically segmented using deep learning to identify major neural and connective tissues. Each ONH was then represented as a 3D point cloud. We used PointNet and dynamic graph convolutional neural network (DGCNN) to diagnose glaucoma from such 3D ONH point clouds and to identify the critical 3D structural features of the ONH for glaucoma diagnosis. Both the DGCNN (area under the curve [AUC]: 0.97±0.01) and PointNet (AUC: 0.95±0.02) were able to accurately detect glaucoma from 3D ONH point clouds. The critical points (ie, critical structural features of the ONH) formed an hourglass pattern, with most of them located within the neuroretinal rim in the inferior and superior quadrant of the ONH. The diagnostic accuracy of both geometric deep learning approaches was excellent. Moreover, we were able to identify the critical 3D structural features of the ONH for glaucoma diagnosis that tremendously improved the transparency and interpretability of our method. Consequently, our approach may have strong potential to be used in clinical applications for the diagnosis and prognosis of a wide range of ophthalmic disorders.

Incidence and Progression of Chorioretinal Folds During Long-Duration Spaceflight

The primary contributing factor for development of chorioretinal folds during spaceflight is unknown. Characterizing fold types that develop and tracking their progression may provide insight into the pathophysiology of spaceflight-associated neuro-ocular syndrome and elucidate the risk of fold progression for future exploration-class missions exceeding 12 months in duration. To determine the incidence and presentation of chorioretinal folds in long-duration International Space Station crew members and objectively quantify the progression of choroidal folds during spaceflight. In this retrospective cohort study, optical coherence tomography scans of the optic nerve head and macula of crew members completing long-duration spaceflight missions were obtained on Earth prior to spaceflight and during flight. A panel of experts examined the scans for the qualitative presence of chorioretinal folds. Peripapillary total retinal thickness was calculated to identify eyes with optic disc edema, and choroidal folds were quantified based on surface roughness within macular and peripapillary regions of interest. Spaceflight missions ranging 6 to 12 months. Incidence of peripapillary wrinkles, retinal folds, and choroidal folds; peripapillary total retinal thickness; and Bruch membrane surface roughness. A total of 36 crew members were analyzed (mean [SD] age, 46 [6] years; 7 [19%] female). Chorioretinal folds were observed in 12 of 72 eyes (17%; 6 crew members). In eyes with early signs of disc edema, 10 of 42 (24%) had choroidal folds, 4 of 42 (10%) had inner retinal folds, and 2 of 42 (5%) had peripapillary wrinkles. Choroidal folds were observed in all eyes with retinal folds and peripapillary wrinkles. Macular choroidal folds developed in 7 of 12 eyes (4 of 6 crew members) with folds and progressed with mission duration; these folds extended into the fovea in 6 eyes. Circumpapillary choroidal folds developed predominantly superior, nasal, and inferior to the optic nerve head and increased in prevalence and severity with mission duration. Choroidal folds were the most common fold type to develop during spaceflight; this differs from reports in idiopathic intracranial hypertension, suggesting differences in the mechanisms underlying fold formation. Quantitative measures demonstrate the development and progression of choroidal folds during weightlessness, and these metrics may help to assess the efficacy of spaceflight-associated neuro-ocular syndrome countermeasures.

Technical Parameters Selection on CT Scans Doses Used for Adult Diagnosis in Some Governmental Hospitals in Addis Ababa, Ethiopia

This study had assessed a technical parameters selection used on CT scan for adult diagnosis doses in Tikur Anbesa and Yekatit 12 specialized hospitals in Addis Ababa, Ethiopia. Data on Head, Chest, Abdomen-Pelvic, Abdomen, Brain, HRCT-chest, L-Sacral, and PNS scan regions were collected from a sample of 132. It was analyzed through descriptive statistics on Microsoft Excel 2016. The results were presented in the table, pie chart, line graph, and histogram. The parameter, Eff.mAs, pitch, table feed, and rotation time have strong correlations with CTDIvol, r(132) =0.749, α = 0.00, r (132) = -0.794, α = 0.00, r (132) = -0.708 α = 0.00, and r (132)=0.723, α = 0.00 respectively. Eff. mAs and DLP deviate by far from mean whereas KV, Rotation time, pitch and ED were almost nearly equal. The effects of technical parameters on doses descriptors agree on the theoretical facts, but for different scan regions 120KV was used. The dose descriptors of this study were greater than the studies in other countries. The medical technologist should have selected the appropriate KV based on scan regions. Relevant authorities should monitor the radiation management implementation in CT scan medical imaging procedure in hospitals where CT scan machines are employed.

Temporal trends in the incidence of malignant and nonmalignant primary brain and central nervous system tumors by the method of diagnosis in England, 1993-2017.

Several studies report increases in the incidences of primary central nervous system (CNS) tumors. The reasons for this are unclear. Data on all 188 340 individuals diagnosed with a primary CNS tumor in England (1993-2017) were obtained from the National Cancer Registration and Analysis Service. Data on all computerized tomography (CT) head and magnetic resonance imaging (MRI) brain scans in England (2013-2017) were obtained from the National Health Service Digital. Age-sex-standardized annual incidence rates per 100 000 population (ASR) were calculated by calendar year, tumor behavior, tumor location, and method of diagnosis. Temporal trends were quantified using average annual percent change (AAPC). The ASR for all CNS tumors increased from 13.0 in 1993 to 18.6 in 2017 (AAPC: +1.5%, 95% CI: 1.3, 1.7). The ASR for malignant tumors (52% overall) remained stable (AAPC: +0.5%, 95% CI: -0.2, 1.3), while benign tumors (37% overall) increased (AAPC: +2.6%, 95% CI: 1.2, 4.0). Among the 66% of benign tumors that were microscopically confirmed, the ASR increased modestly (AAPC: +1.3%, 95% CI: 0.5, 2.1). However, among the 25% of benign tumors that were radiographically confirmed, the ASR increased substantially (AAPC: 10.2%, 95% CI: 7.9, 12.5), principally driven by large increases in those who are aged 65+ years. The rate of CT head scans in Accident & Emergency (A&E) increased during 2013-2017, with especially large increases in 65-84 and 85+-year-olds (AAPCs: +18.4% and +22.5%). Increases in CNS tumor incidence in England are largely attributable to the greater detection of benign tumors. This could be the result of the increasing use of neuroimaging, particularly CT head scans in A&E in people who are aged 65+ years.

Estimation of Effective Radiation Dose for CT Head in Pediatric Patients at UCMS: A Cross-Section Study

Introduction: In modern medicine, CT has made tremendous advances, but the use of CT has been accompanied by concerns about patient safety since it delivers higher doses of radiation than most other diagnostic imaging procedures. Children are particularly vulnerable because their rapidly dividing cells are more sensitive to radiation, and they will have more years to undergo cancerous changes. This study aimed to estimate the effective radiation dose received by pediatric patients while having CT heads at UCMS-TH. Materials and Methods: This cross-sectional study was conducted in the Department of Radiodiagnosis &amp; Medical Imaging, UCMS-TH, Bhairahawa, Nepal. Seventy-five pediatric patients were included in this study over five months, from November 2020 to March 2021. The radiation doses were estimated using a convenient technique and data were analyzed using SPSS version 20. Results: The average mean age of the participants was 9.85±4.45 years. There were 69.3% males and 30.7% females. The age group 11-15 years had the highest frequency of patients 54.7%, followed by the age group 6-10 years with 24% patients. The mean and standard deviation of CTDIvol, DLP, and ED of NCCT and CECT head were significantly different between males and females throughout the study. Conclusion: In pediatrics, male NCCT head scans had higher ED, whereas female CECT head scans had a maximum ED. The age range of 11-15 years had the maximum ED, followed by the age group of 6-10 years.

Spying the dog: Wearable action camera as a tool to understand dog’s behaviour during homing (Carnivora: Canidae)

Automated data collection methods, such as using GPS collars and animal-borne cameras, represent an efficient way of data collection and may be instrumental in the research of animal orientation, including magnetoreception. In this study, we designed a wearable dog action camera (DAC) system for hunting dogs consisting of a Garmin Virb Elite camera housed in the stainless mount attached to the dog harness. We evaluated the DAC’s reliability and potential to capture various behaviour, and we tested the effect of the DAC on the dog’s activity and well-being. We found no significant impact of the DAC on the dogs’ average speed. The tested system was reliable, efficient and safe for dogs. We recorded various behaviours connected to orientation, such as olfactory behaviour and head scanning, the latter described for the first time in domestic dogs. Furthermore, we observed other important behaviours such as hunting, exploration and comfort behaviour. Using wearable action cameras for studying domestic and free-roaming tame animals can bring new opportunities for future behavioural and sensory ecology research.