Volume-rendering Technique Research Articles

Evaluation of the Accuracy of 3D Printed Patient-Specific Brain Biopsy Guide Using 3D Volume Rendering Technique in Canine Cadavers

The objective of this study was to evaluate the accuracy of a CT-based, 3D-printed, patient-specific brain biopsy guide (3D-psBBG) through the application of a transfrontal approach in canine cadavers. A total of ten canine cadavers, with weights ranging from 4.36 to 14.4 kg, were subjected to preoperative CT scans to generate 3D skull models. Customized biopsy guides were created based on these models and manufactured using 3D printing technology. Twenty spinal needle insertions were performed, and the accuracy of needle placement was evaluated through both CT and 3D volume-rendering techniques. The mean needle placement error was 2.1 mm, with no significant differences observed between insertions targeting the fronto-olfactory and piriform lobes. The 3D volume-rendering method demonstrated superior accuracy compared to the CT method, with statistically significant differences in placement errors for both targets. The average time required for the design and manufacture of the guides was 249 min. These findings indicate the high accuracy and potential clinical application of CT-based 3D-psBBG for improving diagnostic outcomes in veterinary neurology.

Utility of the morphological scoring of costal cartilage ossification in age estimation of adult Egyptians using multidetector computed tomography

Abstract Age estimation of adults is a challenging procedure in forensic practice. Inspired by the previous work by Chinese scholars, we established population specific age estimation models from the osseous and calcified projections (OCP) of costal cartilages, using three-dimensional volume-rendering technique. A total of 168 clinical CT scans (2 mm slice thickness) were used to develop the sex-specific age prediction models from a sample of Egyptians, comprising 70 females and 98 males, with documented ages between 12 and 85 years. The sample was also used for validating the Chinese model. We reported the differences between the predictive accuracy of the Egyptian (population specific) and Chinese (non population specific) models. The most accurate age estimation model was stepwise linear regression with standard error of estimates (SEE) of 10.9 and 11.8 years in males and females, respectively. For the simple linear regression models, the most accurate formula included OCP of the right second costal cartilage in males and OCP of the left third costal cartilage in females with SEE of 11.2 and 12.2 years, respectively and mean absolute error (MAE) of 8.8 and 9.6 years, respectively. By comparison, the best accuracy rates produced by the Chinese vs. the Egyptian models in males and females within 5 years were 30.61% and 32.86% vs. 35.71% and 32.86%, respectively, whereas within 10 years, the accuracy rates increased up to 57.14% and 58.57% vs. 72.45% and 64.29%, respectively. Although the accuracy rates from the Chinese models were lower than those obtained from the Egyptian models, the MAE and least error values were comparable in both sexes. Notable accurate age estimation rates in the advanced age group ≥40 years were reached being 81.25% to 97.92% in males and 69.77% to 93.02% in females. OCP of the right first costal cartilage was the most accurate in cross-population application for males and females with MAE values of 10.7 and 11.03 years, respectively with balanced accuracy rates of age estimation using the 10-year interval and 40-year cutoff.

Distinguishing Laterality in Brain Injury in Rabbit Fetal Magnetic Resonance Imaging Using Novel Volume Rendering Techniques

Introduction: Our laboratory has been exploring the MRI detection of fetal brain injury, which previously provided a prognostic biomarker for newborn hypertonia in an animal model of cerebral palsy (CP). The biomarker relies on distinct patterns of diffusion-weighted imaging-defined apparent diffusion coefficient (ADC) in fetal brains during uterine hypoxia-ischemia (H-I). Despite the challenges posed by small brains and tissue acquisition, our objective was to differentiate between left and right brain ADC changes. Methods: A novel aspect involved utilizing three-dimensional rendering techniques to refine ADC measurements within spheroids encompassing fetal brain tissue. 25-day gestation age of rabbit fetuses underwent global hypoxia due to maternal uterine ischemia. Results: Successful differentiation of left and right brain regions was achieved in 28% of the fetal brains. Ordinal analysis revealed predominantly higher ADC on the left side compared to the right at baseline and across the entire time series. During H-I and reperfusion-reoxygenation, the right side exhibited a favored percentage change. Among these fetal brains, 73% exhibited the ADC pattern predictive of hypertonia. No significant differences between left and right sides were observed in patterns predicting hypertonia, except for one timepoint during H-I. This study also highlights a balance between left-sided and right-sided alterations within the population. Conclusion: This study emphasizes the importance of investigating laterality and asymmetric hemispheric lesions for early diagnosis of brain injury, leading to CP. The technological limitations in obtaining a clear picture of the entire fetal brain for every fetus mirror the challenges encountered in human studies.

Realistic three-dimensional imaging of injuries in forensic medicine - Survey-based method comparison of CRT and VRT

ObjectiveA comparison between Cinematic Rendering Technique (CRT) and Volume Rendering Technique (VRT) in cases with postmortem CT-angiography (PMCTA) was carried out. MethodsFor different injuries seen in PMCTA, a VRT and a CRT image of exactly the same pathological section was generated. Two questionnaires were created, one with CRT and one with VRT reconstructions, with the same questions per 3D-image. The questionnaires were sent to forensic pathologists, lawyers and police officers. In total eleven different injuries had to be analyzed. ResultsIn total 109 questionnaires were answered fully. Of these returnees, 36 stated that they were forensic pathologists. Seventy-three people were assigned to the group of medical laypersons, in the study this group consists mainly of police officers, judges and lawyers. Between the two software programs CRT and VRT that were compared, no significant difference could be identified in any of the participating groups with regard to the assessment of the life-threatening nature of the injury images shown. When asked about the comprehensibility of pathology, there was a significant difference in favour of CRT. This advantage was apparent to named medical laypersons and to forensic pathologists. ConclusionsThe study showed a positive trend that CRT may be more understandable than VRT. Not only the medical laypersons, but also the forensic physicians found CRT to be beneficial.

Retinal vessel volume reference database derived from volume-rendered optical coherence tomography angiography

Optical coherence tomography angiography (OCTA) enables three-dimensional reconstruction of the functional blood vessels in the retina. Therefore, it enables the quantification of 3D retinal vessel parameters such as surface area and vessel volume. In spite of the widespread use of OCTA, no representative volume-rendered vessel volume (VV) data are published to date. In this study, OCTA 3 × 3 mm macular cubes were processed with volume-rendering techniques to measure VV in 203 eyes from 107 healthy volunteers. Generalized linear models (GLM) were constructed to assess the impact of age, gender, visual acuity (VA), spherical equivalent (SE), and axial length (AL) on VV. Overall mean VV was 0.23 ± 0.05mm3. Age and axial length showed a negative correlation with VV. However, GLM model analysis found that AL exerted the most pronounced influence on VV. No statistically significant associations were identified between gender or between left and right eyes. This is the first study to assess 3D OCTA VV and its naturally occurring variations in a large series of healthy subjects. It offers novel insights into the characterization of normal retinal vascular anatomy in healthy individuals, contributing to a valuable reference for future research in this field.

The profunda artery perforators: Anatomical study and radiological findings using computed tomography angiography in patients undergoing PAP flap breast reconstruction

The popularity of the profunda femoris artery perforator (PAP) flap is increasing; however, knowledge concerning the standardization of radiological findings and their clinical implications is limited. We evaluated the radiological architecture of posterior thigh perforators using Computed Tomography Angiography (CTA) to identify landmarks to facilitate flap dissection. A retrospective study was conducted on 35 patients who underwent unilateral breast reconstruction with a PAP flap. The preoperative CTA scans were analyzed, and the perforator characteristics were evaluated. The perforators were mapped using a Cartesian coordinate system. Data were normalized by anatomical landmarks and overlapped. Perioperative and postoperative results were analyzed. Radiological and intraoperative were compared. Two CTA scans were excluded; 66 thighs were examined. The mean perforator number was 3.2. The mean diameter of chosen perforators was 2.7mm (DS±0.6mm) at the origin, 2.2mm (DS±0.4mm) at the adductor space midpoint, and 1.7mm (DS±0.3mm) at the deep fascia. The mean adipose tissue thickness was 3.35cm (DS±0.94) at the deep fascia and 3.59cm (DS±1.19) at the adductor space midpoint. Intraoperatively, the perforator was located 3.22cm (DS±0.87) from the posterior border of the gracilis muscle and 8.98cm (DS±1.44) from the inferior gluteal crease. A radiological area located 9.33cm (DS±4.81) from the y-axis and 7.48cm (DS±1.88) from the x-axis was identified. CTA using the volume-rendering technique is a valuable method to study in vivo the radiological anatomy of the posterior thigh perforators.

Improved visualization of cochlear implant electrodes on photon counting detector CT

AbstractBackgroundCochlear implants (CIs) are used to rehabilitate moderate to profound sensorineural hearing loss and stimulate the auditory system via a multichannel electrode array positioned in the scala tympani. Imaging evaluation of CIs is substantially degraded by metallic artifacts. Photon‐counting detector (PCD)‐CT has the potential to minimize such artifacts, though this has not been convincingly established in prior studies. This study compared the visualization of CI electrodes on PCD‐CT to conventional energy integrating detector (EID)‐CT.Materials and MethodsFive patients with CIs were prospectively recruited to undergo temporal bone imaging on both EID‐CT and PCD‐CT scanners yielding 2D and 3D Volume Rendering Technique (VRT) images. Three nonblinded neuroradiologists reviewed 2D and 3D VRT images for the ability to resolve CI electrode leads using a Likert scale. The average Likert scores of PCD‐CT versus EID‐CT were calculated for each reader for both 2D and 3D VRT images. (Likert scores 1–5 based on inferior to superior rating of PCD‐CT compared to EID‐CT). Inter‐rater agreement was assessed using Krippendorff's alpha with ordinal weights. ResultsFive patients underwent temporal bone CT for CI array evaluation. As evidenced by 5‐point Likert scales that were independently used by the three reviewers, this study demonstrated superior resolution of CI electrode array using PCD‐CT as compared to EID‐CT with an average score of 4.2 ± 0.8 for 2D images and 4.9 ± 0.4 for 3D VRT images.ConclusionsPCD‐CT is superior to EID‐CT in the visualization of CI electrodes, particularly in 3D VRT imaging.

The guiding value of the cinematic volume rendering technique in the preoperative diagnosis of brachial plexus schwannoma.

This study aimed to explore and compare the guiding value of Maximum Intensity Projection (MIP) and Cinematic Volume Rendering Technique (cVRT) in the preoperative diagnosis of brachial plexus schwannomas. We retrospectively analyzed the clinical and imaging data of 45 patients diagnosed with brachial plexus schwannomas at the First Affiliated Hospital of Zhengzhou University between January 2020 and December 2022. The enhanced three-dimensional short recovery time inversion-recovery fast spin-echo imaging (3D-STIR-SPACE) sequence served as source data for the reconstruction of MIP and cVRT. Two independent observers scored the image quality and evaluated the location of the tumor and the relationship between the tumor and the brachial plexus. The image quality scores of the two reconstruction methods were compared using the nonparametric Wilcoxon signed-rank test, and the consistency between the image and surgical results was assessed using the weighted kappa. Compared to MIP images, cVRT images had a better performance of overall image quality (p < 0.001), nerve and lump visualization (p < 0.001), spatial positional relationship conspicuity (p < 0.001), and diagnostic confidence (p < 0.001). Additionally, the consistency between the cVRT image results and surgical results (kappa =0.913, P<0.001) was higher than that of the MIP images (kappa =0.829, P<0.001). cVRT provides a high guiding value in the preoperative diagnosis of brachial plexus schwannomas and is an important basis for formulating surgical plans.

Stature estimation from the scapula measurements using 3D-volume rendering technique by regression equations in the Northern Indian population.

The present study assessed the correlation between the stature and scapular measurements from both sides in order to develop population-specific regression equations to estimate the stature from measurements of the scapula in a contemporary Northern Indian population individually for the left and right sides. A total of 597 cadavers underwent postmortem multidetector computed tomography and subsequent medicolegal autopsy in our department between August 2021 and August 2022. Two hundred samples (100 males and 100 females) were randomly collected based on inclusion and exclusion criteria. Six linear anthropometric measurements of the scapula from either side were measured using the 3D volume-rendered technique by an electronic cursor. Each anthropometric measurement showed a significant difference between males and females (p < 0.05). Regression analysis was applied to match the taken measurements against stature. The accuracy to predict stature ranged from 3.99 to 4.94 cm for males and from 4.49 to 5.27 cm for females, respectively. Left-sided measurements were better predictors of stature than the right side in both genders. The results of this study indicate that scapular measurements could be useful to estimate the stature of Northern Indian individuals, particularly in scenarios of disaster victim identification lacking long bones, which are considered to be better predictors to date.

Clinical Consideration of Anatomical Variations in the Common Hepatic Arteries: An Analysis Using MDCT Angiography.

The purpose of this study was to determine the prevalence of normal hepatic vascularization and variations in the common hepatic arteries using multidetector computer tomography angiography. These variants should be acknowledged before any surgery of the upper abdomen. The aim of our work was to analyze the variations in the hepatic arteries and their possible clinical and surgical implications. This study was carried out on 4192 patients who underwent 64-slice MDCT angiography, from August 2015 to December 2021. We used surface and volume-rendering techniques in order to post-process images of the vascular components in the desired area. We highlighted 76 cases with replaced common hepatic arteries, which are characterized by the origin of the common hepatic artery trunk located outside the classical composition of the celiac trunk. We identified three levels of origin: the abdominal aorta, the superior mesenteric artery and the left gastric artery. We observed six different aspects of the morphological variability of the celiac trunk and the superior mesenteric artery. The trajectory of the artery trunk, between the aortic origin and the hepatic pedicle portion of the hepatic portal vein, is variable and we analyzed the pancreatic trajectory accordingly. The prevalence of hepatic arterial variants found during this study was similar to that in other specialized studies. We came across variants that have not been described in the well-known classification of Michels and even described extremely rare variations. The study of abnormal hepatic vascularization plays an important role in the surgical planning of hepatic transplantation, liver and pancreatic resection and extrahepatic upper abdominal surgeries.

Comparison of maximum intensity projection and volume rendering on multidetector computed tomography in detecting pulmonary nodules

BackgroundLung cancer is the one of the most common types of cancer and considered as a leading cause of death from neoplasms. Almost all types of lung cancer develop from pulmonary nodules. The wide availability of the multi-detector computed tomography (MDCT) scanners makes the detection of pulmonary nodules much easier. Volume rendering (VR) and maximum intensity projection (MIP) techniques are the most commonly used post-processing techniques. The purpose of this research is to compare and contrast the two techniques in terms of the number and size of nodules.ResultsIn the current study, 32 patients with pulmonary nodules were included being referred from the chest department, with their age ranging from 27 to 71 years old. Nodules characteristics, such as number and size, were evaluated on both MIP and VR techniques. Paired comparison of number of pulmonary nodules less than 6 mm between MIP and VR showed statistically significant difference in 4, 7 and 10 mm slip thickness with P-value 0.003, 0.0001 and 0.0001, respectively. Paired comparison of number of pulmonary nodules more than 6 mm in size between MIP and VR showed no statistically significant difference in 4, 7 and 10 mm slip thickness with P-value > 0.05 each. Comparison of the pulmonary nodules numbers according to slip thickness showed that there was a statistically significant difference in the number of detected nodules, showing that 10 mm slip thickness is significantly higher compared to 4 mm and 7 mm with P-value 0.0001, 0.0001 for nodules < 6 mm, and 0.001 for the lung nodules > 6 mm in size.ConclusionsWe can conclude the superiority of MIP over VR in detection of small sized nodules. MIP was easier to follow and showed high inter-reader agreement. The 10 mm MIP outperformed all other slab thicknesses for nodule detection less than 6 mm. There was no statistically significant difference between both techniques in terms of larger nodules measuring > 6 mm.

Volume Prediction of Extended Latissimus Dorsi Musculocutaneous Flap for Breast Reconstruction Using a Computed Tomography Volume-Rendering Technique with an X-ray Contrast Thread Marking.

The extended latissimus dorsi (ELD) musculocutaneous flap is one of the surgical techniques used for breast reconstruction. Preoperative preparation to determine the exact amount of flap tissue to be harvested is important to achieve a good outcome with autologous tissue reconstruction. However, few reports exist on objective preoperative volume prediction of ELD flaps. The purpose of this study was to quantify the elevated ELD volume as a preoperative plan. Patients who underwent immediate or delayed breast reconstruction with ELD flap after mastectomy between March 2015 and January 2022 are included. (1) The ELD flap was designed preoperatively, X-ray contrast thread was applied along the design, and CT imaging was performed in the same lateral supine position as the surgical position. 3D images were constructed, and the volume-rendering method was used to obtain the integrated volume. (2) Intraoperative ELD flap volume was calculated using the water displacement method. The correlation between (1) and (2) was examined. (1) The mean preoperative predicted value was 290.2 mL and (2) the mean intraoperative ELD flap volume was 298.3 mL. The correlation coefficient between the two volumes was 0.93, indicating that they were correlated. We could quantify the ELD flap volume using the volume-rendering method with X-ray contrast threads. This study could be a useful method for preoperative prediction planning of the ELD flap in breast reconstruction. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Path Tracing vs. Volume Rendering Technique in Post-Surgical Assessment of Bone Flap in Oncologic Head and Neck Reconstructive Surgery: A Preliminary Study.

This study aims to compare a relatively novel three-dimensional rendering called Path Tracing (PT) to the Volume Rendering technique (VR) in the post-surgical assessment of head and neck oncologic surgery followed by bone flap reconstruction. This retrospective study included 39 oncologic patients who underwent head and neck surgery with free bone flap reconstructions. All exams were acquired using a 64 Multi-Detector CT (MDCT). PT and VR images were created on a dedicated workstation. Five readers, with different expertise in bone flap reconstructive surgery, independently reviewed the images (two radiologists, one head and neck surgeon and two otorhinolaryngologists, respectively). Every observer evaluated the images according to a 5-point Likert scale. The parameters assessed were image quality, anatomical accuracy, bone flap evaluation, and metal artefact. Mean and median values for all the parameters across the observer were calculated. The scores of both reconstruction methods were compared using a Wilcoxon matched-pairs signed rank test. Inter-reader agreement was calculated using Spearman's rank correlation coefficient. PT was considered significantly superior to VR 3D reconstructions by all readers (p < 0.05). Inter-reader agreement was moderate to strong across four out of five readers. The agreement was stronger with PT images compared to VR images. In conclusion, PT reconstructions are significantly better than VR ones. Although they did not modify patient outcomes, they may improve the post-surgical evaluation of bone-free flap reconstructions following major head and neck surgery.

Preoperative Triple-Phase Three-Dimensional-Multi-Detector Computed Tomography Imaging of the Hepatic Vascular Tree: An Accurate Road Map Prior to Tumor Resection in Hepatoblastoma.

To evaluate the hepatic vasculature/tumor relations in hepatoblastoma patients with three-dimensional (3D) reformatted images after triple-phase multi-detector computed tomography (MDCT) and to compare these with the surgical findings to judge the accuracy of this investigation. The study was carried out in hepatoblastoma patients after appropriate neo-adjuvant chemotherapy, prior to resection. Images were postprocessed at a dedicated workstation for multi-planar reformations, maximum intensity projection, curved planar reformations, and volume-rendered technique reconstructions. The reporting was done as per a specific protocol by both the radiologist and surgeon (per-operative findings) and the accuracy of MDCT ascertained as per concordance between the surgical and imaging findings. Fourteen children (13 boys, 1 girl) underwent surgery. Clinically, relevant information regarding vascular, tumor involvement, and interface with vessels was provided by the study in all cases. Although all tumors were deemed resectable on preoperative imaging, one procedure was abandoned due to an unanticipated portal cavernoma. While a few anatomical variations were unexpectedly encountered during surgery, there was good concordance overall between findings on imaging and surgical exploration. MDCT with 3D reformatting provides accurate virtual representations of the hepatic tumor. This allows simulation of surgical resection with decreased risk of vascular injury and postoperative liver failure.

Handmade models for aneurysm surgery: A useful tool for training.

Aneurysm surgery is considered difficult by young and trainee neurosurgeons. This is due to difficulty in understanding orientation of aneurysm complex (proximal and distal vessels, aneurysm neck, and fundus) in relation to the surrounding structures (skull, brain, vessels, and nerves) after head is rotated, extended, and fixed on the head frame. Virtual three-dimensional (3D) imaging studies and 3D-printed models help young neurosurgeons but are not accessible to most of the centers due to need for resources (human and equipment). Authors used handmade 3D models of aneurysm complex to train young neurosurgeons before and during surgery to make them understand steps to treat it. RadiAnt DICOM viewer software (2022.1.1, 64-bit, Medixant, Poznan, Poland) was used for acquiring 3D Volume Rendering Technique images to make aneurysm models preoperatively. Twisted 20 Gauze galvanized iron wires were used for making proximal and distal branches and Epoxy Putty (M-seal, Pidilite ® industries, Mumbai, India) was used to make smooth surfaces of the vessels, aneurysm necks, and fundi. Models were used in operating room (OR) before and during surgery to help surgeons and trainees get oriented to the aneurysm complexes. Handmade models, oriented as per patients' head position, were useful to make surgeons and trainees to understand projection of various components of the aneurysm complex in relation to adjacent structures, especially skull base, during both preoperative planning and in OR even before completion of the dissection. Handmade models of aneurysms are inexpensive tool and can help trainee neurosurgeons to plan and execute surgical management of aneurysms.

Acquisition and Visualization of Micro-Vibration of a Sound Wave in 3D Space

The acquisition of micro-vibrations is important for analyzing machinery. In the present study, we propose a method for measuring and visualizing the three-dimensional (3D) displacements of such micro-vibrations, especially in the case of sound waves propagating through space. The proposed method uses the speckle patterns of coherent light to measure the minute displacements. Speckle patterns are useful for detecting extremely small displacements owing to their sensitivity to the pose of the object. However, it is impossible to measure the displacement at each position because the pattern changes nonlinearly with respect to large depth changes. Therefore, a method of nonlinear low-dimensional embedding of the speckle pattern is proposed to analyze the displacements and extended to measure micro-displacements in a 3D space. We divided the 3D space into multiple slices and synchronously captured each speckle pattern. The displacements in the entire 3D space were simultaneously recovered by optimizing the embedded vectors, which were consistent in a 3D lattice. The propagation of sound waves in the 3D space was visualized using the volume-rendering technique. The experiments confirmed that the proposed method correctly measured the displacements by comparing them with the ground truth captured by microphones. We also visualized the wavefront of the sound wave propagating through space.

3D Cinematic Volume-Rendering Technique of Traumatic Spine Injuries: A Powerful Tool for Radiology Education

Spine trauma represents a common indication for imaging in the emergency department. Multidetector CT imaging, with its advantage of multiplanar reconstructions and fast image acquisition, is the technique of choice in the initial assessment of a patient with polytrauma. While many simple spinal fractures are adequately evaluated on 2D multiplanar reconstruction images, more complex, potentially displaced fracture patterns can be more fully highlighted on 3D reconstructions. Compared with conventional volume-rendering techniques, cinematic rendering uses a complex illumination model to create a more photorealistic representation of the fracture patterns, images that are certain to excite both trainees and clinicians. This review demonstrates the educational value and clinical utility of 3D cinematic rendering images in understanding complex spinal column injuries.Learning Objective: To demonstrate the methodology, clinical applicability, and educational utility behind 3D photorealistic cinematic rendering images of spine injuries, with emphasis on the “tension bands” biomechanical concept

Orthographic Pooling: Learned Maximum Intensity Projection for Vertebrae Labelling.

Maximum intensity projection (MIP) is a standard volume-rendering technique for 3D volumetric data processing. For example, given a 3D CT data, it simply projects the voxel values with its maximum intensity on a specific view to output a 2D image. Recently, MIP is further combined with Btrfly Net for vertebrae labelling task. However, this simple reformations of 3D data leads to loss of rich context information in volumetric data. In this paper, we propose a learned orthographic pooling approach instead of image processing based MIP. Typically, a simple conv-simple and bottleneck pooling modules are introduced to learn the orthographic projection of 3D data and output 2D intermediate feature maps. To this end, the learned orthographic pooling helps preserve detail information of 3D context during projection. Furthermore, an unified Btrfly Net is provided for vertebrae labelling by integrating the orthographic pooling sub-network. The novel Btrfly Net with orthographic pooling sub-network is evaluated on the 2014 MICCAI vertebra localization challenge dataset. Compared to original Butfly Net with MIP, orthographic pooling, the learned MIP largely boosts the performance of vertebrae labelling.

Left appendage morphology as risk factors for cardio-embolism in patients with stroke of undetermined source

Abstract Background Left atrium (LA) volume and function and certain left atrial appendage (LAA) morphologies are known to be strongly associated with the risk of thrombus formation and thromboembolism in patients with atrial fibrillation (AF). Little is known about the role of LA parameters and LAA morphology in patients with Embolic Stroke of Undetermined Source (ESUS). Purpose To assess LA volume and function and LAA morphologies in ESUS patients and the potential association with cardioembolic risk. Methods Twenty consecutive patients with ESUS who underwent contrast enhanced electrocardiogram-gated computed tomography (CT) as part of stroke etiology evaluation were matched by age and gender to patients with and without history of AF (twenty in each group) who had CT as part of standard evaluation before transcatheter aortic valve implantation. LA maximum (LAVmax) and minimum (LAVmin) volumes and function, measured as total emptying volume (LAEV) and total emptying fraction (LAEF) were assessed, and three- dimensional structures of the LA and LAA were constructed using the volume-rendered post-processing technique. Results The mean age of patients was 75.9±8.61, 76.1±8.52, 77.8±7.72) in the ESUS, AF and non-AF groups, respectively, with 11 (55%) females in each group. Compared to patients with ESUS, patients with AF showed significantly greater LAVmax (100.59±31.59 ml vs.155.78±63.15 ml, respectively, p=0.001) and LAVmin (71.38±30.69 ml vs. 140.73±64.60 ml; respectively, p&amp;lt;0.001), while LAV max and LAVmin were similar, in patients with ESUS and non-AF. The distribution of LAA morphologies significantly differed between patients with ESUS and patients with AF and non-AF: 1 (5%) vs. 9 (45%) chicken-wing; 14 (70%) vs. 8 (40%) cauliflower; and 5 (25%) vs. 3 (15%) Cactus; respectively. Conclusion LA appendage morphology, but not LA volume, seems to be associated with ESUS. LAA morphologies with multiple lobes, cauliflower and cactus, seems to be associated with ESUS. Larger studies are needed to confirm these associations. Funding Acknowledgement Type of funding sources: None.

Simulation of surgery for supratentorial gliomas in virtual reality using a 3D volume rendering technique: a poor man's neuronavigation.

Different techniques of performing image-guided neurosurgery exist, namely, neuronavigation systems, intraoperative ultrasound, and intraoperative MRI, each with its limitations. Except for ultrasound, other methods are expensive. Three-dimensional virtual reconstruction and surgical simulation using 3D volume rendering (VR) is an economical and excellent technique for preoperative surgical planning and image-guided neurosurgery. In this article, the authors discuss several nuances of the 3D VR technique that have not yet been described. The authors included 6 patients with supratentorial gliomas who underwent surgery between January 2019 and March 2021. Preoperative clinical data, including patient demographics, preoperative planning details (done using the VR technique), and intraoperative details, including relevant photos and videos, were collected. RadiAnt software was used for generating virtual 3D images using the VR technique on a computer running Microsoft Windows. The 3D VR technique assists in glioma surgery with a preoperative simulation of the skin incision and craniotomy, virtual cortical surface marking and navigation for deep-seated gliomas, preoperative visualization of morbid cortical surface and venous anatomy in surfacing gliomas, identifying the intervenous surgical corridor in both surfacing and deep-seated gliomas, and pre- and postoperative virtual 3D images highlighting the exact spatial geometric residual tumor location and extent of resection for low-grade gliomas (LGGs). Image-guided neurosurgery with the 3D VR technique using RadiAnt software is an economical, easy-to-learn, and user-friendly method of simulating glioma surgery, especially in resource-constrained countries where expensive neuronavigation systems are not readily available. Apart from cortical sulci/gyri anatomy, FLAIR sequences are ideal for the 3D visualization of nonenhancing diffuse LGGs using the VR technique. In addition to cortical vessels (especially veins), contrast MRI sequences are perfect for the 3D visualization of contrast-enhancing high-grade gliomas.