Visualization Of Anatomical Structures Research Articles

Effect of patient characteristics on aortic attenuation in iodinated contrast-enhanced Abdominopelvic CT: A retrospective study

IntroductionContrast Enhanced Computed Tomography (CECT) abdomen and pelvis is a common imaging procedure. Hospitals typically follow fixed protocols of contrast volume administration for triple-phase CECT abdomen and pelvis scans and have found that patients are either underdosed or overdosed with respect to their body habitus. The aim of the study was to correlate different patient characteristics such as Total body weight (TBW), Lean Body Mass (LBM), Body Mass Index (BMI), Body Surface Area (BSA) and Blood Volume (BV) with aortic enhancement in the arterial and portal venous phases for CECT Abdomen and pelvis. MethodsA total of 106 patients who underwent triple-phase CECT abdomen & pelvis were retrospectively studied. A circular region-of-interest (ROI) of 100 mm2 was positioned on descending aorta for unenhanced, arterial, and portal venous phases to measure the aortic enhancement in Hounsfield's units. Measure of contrast attenuation (ΔH) was calculated from the difference of CT values on unenhanced images and contrast images. Correlation analysis was performed to evaluate the relation of patient body characteristics with aortic enhancement. ResultsCorrelation analysis revealed that BMI exhibited the least correlation when compared to the other characteristics in both arterial (r = −0.3; p = 0.002) and portovenous phases (r = −0.35; p < 0.001) whereas TBW, LBW, BSA and BV reported moderate inverse correlations. BV was found to be the strongest of all characteristics under linear regression. ConclusionThe study supports the use of protocols that adjust contrast volume to either TBW, LBW, BSA, or BV for CT abdomen and pelvis scan. Implication of practiceThe right body parameter ensures optimal contrast enhancement, improving the visualization of anatomical structures and helps in adapting tailored contrast injection protocols.

Optimizing outcomes in catheter ablation for typical atrial flutter: a comparative study of intracardiac echocardiography versus fluoroscopy guidance

Abstract Background Catheter ablation is a standard intervention for typical atrial flutters, specifically targeting the cavotricuspidal isthmus (CTI). Intracardiac echocardiography (ICE) plays a pivotal role in providing real-time visualization of anatomical structures during the electrophysiology procedure, thereby enhancing safety and potentially reducing reliance on fluoroscopy, leading to improved procedural outcomes. We aimed to conduct a comparative analysis of procedural and follow-up outcomes between ICE-guided and fluoroscopy-only guided catheter ablations for CTI in patients undergoing treatment for typical atrial flutter. Methods A retrospective analysis was conducted at our university center, encompassing 376 consecutive patients in a single-center study. Of these, 158 underwent procedures guided solely by fluoroscopy, while 218 received ICE-guided CTI ablation. Results ICE-guidance demonstrated a statistically significant reduction in fluoroscopy time (72 [36; 170] s vs. 888 [578; 1184] s; p&amp;lt;0.01), total procedure time (70 [52; 90] min vs. 90 [60; 105] min; p&amp;lt;0.01), total ablation time (692 [435; 998] s vs. 920 [629; 1373] s; p&amp;lt;0.01), and the duration from the first to last ablation (20.5 [12; 37] min vs. 41.0 [26.8; 59.3] min; p&amp;lt;0.01). Both groups achieved a 100% acute success rate without major complications. The ICE-guided group exhibited a significantly superior long-term success rate (ICE-guided group: 95.74%, fluoroscopy-only group: 89.26%; p=0.048) compared to the fluoroscopy-only group at an average follow-up length of 34 months. Conclusion The utilization of ICE-guidance for CTI ablation significantly reduces fluoroscopy exposure, procedure time, and ablation time, ultimately contributing to enhanced long-term success rates when compared to the conventional fluoroscopy-only approach.

The gamma-variate in contrast-enhanced imaging: a unified view and method from computed to electrical impedance tomography

Objective. Modern medical imaging plays a vital role in clinical practice, enabling non-invasive visualization of anatomical structures. Dynamic contrast enhancement (DCE) imaging is a technique that uses contrast agents to visualize blood flow dynamics in a time-resolved manner. It can be applied to different modalities, such as computed tomography (CT) and electrical impedance tomography (EIT). This study aims to develop a common theoretical and practical hemodynamic extraction basis for DCE modelling across modalities, based on the gamma-variate function. Approach. The study introduces a framework to generate time-intensity curves for multiple DCE imaging modalities from user-defined hemodynamic parameters. Thus, extensive datasets were simulated for both DCE-CT and EIT, representing different hemodynamic scenarios. Additionally, gamma-variate extensions to account for several physiological effects were detailed in a modality-agnostic manner, and three corresponding fitting strategies, namely nonlinear, linear, and a novel hybrid approach, were implemented and compared on the basis of accuracy of parameter estimation, first pass reconstruction, speed of computation, and failure rate. Main results. As a result, we found the linear method to be the most modality-dependent, exhibiting the greatest bias, variance and failure rates, although remaining the fastest alternative. The hybrid method at least matches the state-of-the-art nonlinear method’s accuracy, while improving its robustness and speed by 10 times. Significance. Our research suggests that the hybrid method may bring noteworthy accuracy and efficiency improvements in handling the high-dimensionality of DCE imaging in general, being a step towards real-time processing. Moreover, our generative model presents a potential asset to produce benchmarking and data augmentation datasets across modalities.

A cone beam computed tomographic study on foramen transversarium

The foramen transversarium is a vital feature found in the cervical vertebrae of the spine. It serves as a protective passageway for the vertebral artery and vertebral vein, supplying blood to the brain and spinal cord. Any compromise to these structures within the foramen can lead to severe neurological complications, emphasizing its clinical significance. The study was carried out on 83 subjects of typical cervical vertebrae. Among them were 42 males and 41 females. All the foramen transversaria were observed for any anatomical variations. The anteroposterior, transverse diameters of all the foramen transversaria and the distance between the medial margin of uncinate process to the foramen transversarium were measured. The average transverse diameter of typical cervical vertebrae and seventh cervical vertebrae were ± 0.84mm and 5.13 ± 1.22 mm respectively. The average anteroposterior diameters of typical and seventh cervical vertebrae were 4.84 ± 0.69 mm and 3.91 ± 1.17 mm respectively. The distance from medial border of uncinate process to foramen transversaria was 4.28 ± 0.77 mm in typical and 5.44 ± 1.28 mm in seventh cervical vertebrae. The incidence of double bubble foramen in typical cervical vertebrae was reported to be17.5%. The incidence of double foramen transversaria was 12.5% in the seventh cervical vertebrae. Osteophytes were obstructing the foramen transversarium and narrowing it in 25% of vertebrae. In cone beam computed tomography (CBCT), the foramen transversarium plays a pivotal role in precise imaging of the cervical spine. Its significance lies in providing clear visualization of anatomical structures and potential abnormalities, aiding in the accurate diagnosis and treatment planning for various spinal conditions, thus enhancing patient care.

Intraoperative near-infrared fluorescence visualization of anatomical structures in general surgical and urological practice

Aim: to analyze current literature on the assessment of intraoperative near-infrared fluorescence visualization of anatomical structures in general surgical and urological practice. The experience of using intraoperative near-infrared fluorescence visualization of anatomical structures in general surgical and urological practice is analyzed. The priority areas of the method application are defined, the recent clinical studies in various fields of surgery and urology are reviewed. Conclusions. The method of intraoperative near-infrared fluorescence imaging of anatomical structures with abundant vascularization and for assessing oncological prognosis is the most promising.

The Forces Associated with Bolus Injection and Continuous Infusion Techniques during Ultrasound-Targeted Nerve Contact: An Ex Vivo Study

Ultrasound-guided regional anaesthesia with real-time visualization of anatomical structures and needle trajectory has become the standard method for accurately achieving nerve block procedures. Nevertheless, ultrasound is particularly limited in accurately detecting the needle tip in tissues with complex echogenicity. Fat-filled circumneural fascial tissue provides a barrier to local anaesthetic diffusion. Injection during gentle needle nerve contact is more likely to spread under the circumneurium (halo sign). On the other hand, excessive force may cause hematoma or activate the piezo ion channels and intraneural calcium release. Therefore, it is vital to understand the mechanics of needle–tissue interaction for optimizing the procedural outcomes and patients’ safety. We hypothesised that continuous fluid infusion would reduce the needle force applied on the nerve compared to that of bolus injection. Thus, the primary objective of this study was to compare the forces associated with the bolus injection and continuous infusion techniques on the sciatic nerves of fresh lamb legs ex vivo. A needle combining pressure and force was inserted into six legs of lambs ex vivo using a motor stage at a constant velocity and imaged with a linear transducer. Saline injections were block randomised to bolus injection or infusion in the muscle upon gently touching and indenting of the epineurium at nine sites on six sciatic nerves at three angles (30°, 45° and 60°) in each location. The bolus was delivered over 6 s and infused for over 60 s. The result showed less force was generated during the infusion technique when gently touching the epineurium than that of the bolus technique, with p = 0.004, with significant differences observed at a 60° angle (0.49 N, p = 0.001). The injection pressure was also lower when light epineurium touches were applied (9.6 kPa, p = 0.02) and at 60° (8.9 kPa). The time to peak pressure varied across the insertion angles (p &lt; 0.001), with the shortest time at 60° (6.53 s). This study explores future applications by emphasizing the significance of understanding needle–tissue interaction mechanics. This understanding is crucial for optimizing the procedural outcomes and enhancing patients’ safety in ultrasound-guided regional anaesthesia administration. Specifically, continuous infusion demonstrated a notable reduction in needle force compared to that of the bolus injection, especially during gentle epineurium contact.

Cinematic Rendering of Pancreatic Neuroendocrine Tumours: Opportunities for Clinical Implementation: Part 2: Preoperative Planning and Evaluation of Metastatic Disease.

Pancreatic neuroendocrine tumours (PNETs) are a rare subset of pancreatic tumours that have historically comprised up to 3% of all clinically detected pancreatic tumours. In recent decades, however, advancements in imaging have led to an increased incidental detection rate of PNETs and imaging has played an increasingly central role in the initial diagnostics and surgical planning of these tumours. Cinematic rendering (CR) is a 3D post-processing technique that generates highly photorealistic images through more realistically modelling the path of photons through the imaged volume. This allows for more comprehensive visualization, description, and interpretation of anatomical structures. In this 2-part review article, we present the first description of the various CR appearances of PNETs in the reported literature while providing commentary on the unique clinical opportunities afforded by the adjunctive utilization of CR in the workup of these rare tumours. This second instalment focuses on the applications of CR in optimizing preoperative planning of PNETs.

Cinematic Rendering of Pancreatic Neuroendocrine Tumours: Opportunities for Clinical Implementation: Part 1: Tumour Detection and Characterization.

Pancreatic neuroendocrine tumours (PNETs) are a rare subset of pancreatic tumours that have historically comprised up to 3% of all clinically detected pancreatic tumours. In recent decades, however, advancements in imaging have led to an increased incidental detection rate of PNETs and imaging has played an increasingly central role in the initial diagnostics and surgical planning of these tumours. Cinematic rendering (CR) is a 3D post-processing technique that generates highly photorealistic images through more realistically modelling the path of photons through the imaged volume. This allows for more comprehensive visualization, description, and interpretation of anatomical structures. In this 2-part review article, we present the first description of the various CR appearances of PNETs in the reported literature while providing commentary on the unique clinical opportunities afforded by the adjunctive utilization of CR in the workup of these rare tumours. The first of these 2 instalments highlights the utility of CR in optimizing PNET detection and characterization.

Fast 5-minute shoulder MRI protocol with accelerated TSE-sequences and deep learning image reconstruction for the assessment of shoulder pain at 1.5 and 3 Tesla

PurposeThe objective of this study was to implement a 5-minute MRI protocol for the shoulder in routine clinical practice consisting of accelerated 2D turbo spin echo (TSE) sequences with deep learning (DL) reconstruction at 1.5 and 3 Tesla, and to compare the image quality and diagnostic performance to that of a standard 2D TSE protocol. MethodsPatients undergoing shoulder MRI between October 2020 and June 2021 were prospectively enrolled. Each patient underwent two MRI examinations: first a standard, fully sampled TSE (TSES) protocol reconstructed with a standard reconstruction followed by a second fast, prospectively undersampled TSE protocol with a conventional parallel imaging undersampling pattern reconstructed with a DL reconstruction (TSEDL). Image quality and visualization of anatomic structures as well as diagnostic performance with respect to shoulder lesions were assessed using a 5-point Likert-scale (5 = best). Interchangeability analysis, Wilcoxon signed-rank test and kappa statistics were performed to compare the two protocols. ResultsA total of 30 participants was included (mean age 50±15 years; 15 men). Overall image quality was evaluated to be superior in TSEDL versus TSES (p<0.001). Noise and edge sharpness were evaluated to be significantly superior in TSEDL versus TSES (noise: p<0.001, edge sharpness: p<0.05). No difference was found concerning qualitative diagnostic confidence, assessability of anatomical structures (p>0.05), and quantitative diagnostic performance for shoulder lesions when comparing the two sequences. ConclusionsA fast 5-minute TSEDL MRI protocol of the shoulder is feasible in routine clinical practice at 1.5 and 3 T, with interchangeable results concerning the diagnostic performance, allowing a reduction in scan time of more than 50% compared to the standard TSES protocol.

Exploring reliable photogrammetry techniques for 3D modeling in anatomical research and education.

In anatomical research and education, three-dimensional visualization of anatomical structures is crucial for understanding spatial relationships in diagnostics, surgical planning, and teaching. While computed tomography (CT) and magnetic resonance imaging (MRI) offer valuable insights, they are often expensive and require specialized resources. This study explores photogrammetry as an affordable and accessible approach for 3D modeling in anatomical contexts. Two photogrammetry methods were compared: conventional open-source software (Colmap) and Apple's RealityKit Object Capture. Human C3 vertebrae were imaged with a 24 MP camera, with and without a cross-polarization filter. Reconstruction times, vertex distances, surface area, and volume measurements were compared to CT scans. Results revealed that the Object Capture method surpassed the conventional approach in reconstruction speed and user-friendliness. Both methods exhibited similar vertex distance from reference mesh and volume measurements, although the conventional approach produced larger surface areas compared to CT-based models. Cross-polarization filters eliminated the need for pre-processing and improved outcomes in challenging lighting conditions. This study demonstrates that photogrammetry, especially Object Capture, as a reliable and time-efficient tool for 3D modeling in anatomical research and education. It offers accessible alternatives to traditional techniques with advantages in texture mapping. While further validation of various anatomical structures is required, the accessibility and cost-effectiveness of photogrammetry make it a valuable asset for the field. In summary, photogrammetry would have the potential to revolutionize anatomical research and education by providing cost-effective, accessible, and accurate 3D modeling. The study underscores the promise of advancing anatomical research and education through the integration of photogrammetry with ongoing improvements in user-friendliness and accessibility.

Diagnostic evaluation of deep learning accelerated lumbar spine MRI.

Deep learning (DL) accelerated MR techniques have emerged as a promising approach to accelerate routine MR exams. While prior studies explored DL acceleration for specific lumbar MRI sequences, a gap remains in comprehending the impact of a fully DL-based MRI protocol on scan time and diagnostic quality for routine lumbar spine MRI. To address this, we assessed the image quality and diagnostic performance of a DL-accelerated lumbar spine MRI protocol in comparison to a conventional protocol. We prospectively evaluated 36 consecutive outpatients undergoing non-contrast enhanced lumbar spine MRIs. Both protocols included sagittal T1, T2, STIR, and axial T2-weighted images. Two blinded neuroradiologists independently reviewed images for foraminal stenosis, spinal canal stenosis, nerve root compression, and facet arthropathy. Grading comparison employed the Wilcoxon signed rank test. For the head-to-head comparison, a 5-point Likert scale to assess image quality, considering artifacts, signal-to-noise ratio (SNR), anatomical structure visualization, and overall diagnostic quality. We applied a 15% noninferiority margin to determine whether the DL-accelerated protocol was noninferior. No significant differences existed between protocols when evaluating foraminal and spinal canal stenosis, nerve compression, or facet arthropathy (all p > .05). The DL-spine protocol was noninferior for overall diagnostic quality and visualization of the cord, CSF, intervertebral disc, and nerve roots. However, it exhibited reduced SNR and increased artifact perception. Interobserver reproducibility ranged from moderate to substantial (κ = 0.50-0.76). Our study indicates that DL reconstruction in spine imaging effectively reduces acquisition times while maintaining comparable diagnostic quality to conventional MRI.

Visualization of anatomical structures in the fetlock region of the horse using cone beam computed tomography in comparison with conventional multidetector computed tomography.

Cone-beam computed tomography (CBCT) is regarded as a convenient and suitable alternative to conventional computed tomography. However, in the horse, the quality of obtained data sets needs to be evaluated. Therefore, the aim of this study was to compare the visibility and accessibility of clinically relevant anatomical structures displayed in CBCT and conventional multidetector computed tomography (MDCT). Twenty-nine limbs from horses euthanized for reasons unrelated to this study were used. Native and intraarticular contrast scans of the fetlock (CBCT vs. MDCT) were performed. The visibility and accessibility of selected anatomical structures were blindly scored by three independent experienced observers using a scoring system previously reported and adapted to the fetlock joint. Only minor differences between CBCT and MDCT were identified concerning the diagnostic quality of images for osseous structures. Soft tissue structures were better evaluated on MDCT images. In CBCT as well as in MDCT articular cartilage could only be visualized after intraarticular injection of contrast medium. Cone beam computed tomography of the fetlock is a useful and reliable diagnostic tool when evaluating osseous structures and delineating articular cartilage with contrast medium. However, this modality is limited for assessing soft tissues structures.

Mixed reality for spine surgery: a step into the future with a human cadaveric accuracy study.

Current application of mixed reality as a navigation aid in the field of spinal navigation points to the potential of this technology in spine surgery. Crucial factors for acceptance include intuitive workflow, system stability, reliability, and accuracy of the method. The authors therefore aimed to investigate the accuracy of the system in visualization of anatomical structures using mixed reality in the example of pedicles of the thoracic spine in a human cadaveric study. Potential difficulties and limitations are discussed. CT scans of a human cadaveric spinal column specimen were performed. After segmentation and import into the advanced HoloLens 2 software, the vertebrae were exposed. The vertebral arches were preserved on one side for a landmark-based surface registration, whereas pedicles were exposed on the other side in order to measure and evaluate deviation of the overlay holographs with regard to the exact anatomical structure. Accuracy was measured and statistically evaluated. In this work it was demonstrated that the overlay of the virtual 3D model pedicles with the real anatomical structures with anatomical landmark registration was within an acceptable surgical accuracy with the mean value of 2.1 mm (maximum 3.8 mm, minimum 1.2 mm). The highest accuracy was registered at the medial and lateral pedicle wall, and the measurement results were best in the region of the middle thoracic spine. The accuracy analysis for mixed reality (i.e., between the virtual and real anatomical situation of the thoracic spine) showed a very good agreement when focus was on the pedicles. This work is thus a rare proof of the precision of segmentation to the potential surgical area. The results encourage researchers to open up mixed reality technology in its development and application for spinal navigation.

Show them what they can't see! An evaluation of the use of customized 3D printed models in head and neck anatomy.

Difficulty in visualizing anatomical structures has been identified as a challenge in anatomy learning and the emergence of three-dimensional printed models (3DPMs) offers a potential solution. This study evaluated the effectiveness of 3DPMs for learning the arterial supply of the head and neck region. One hundred eighty-four undergraduate medical students were randomly assigned to one of four learning modalities including wet specimen, digital model, 3DPM, and textbook image. Posttest scores indicated that all four modalities supported participants' knowledge acquisition, most significantly in the wet specimen group. While the participants rated 3DPMs lower for helping correct identification of structures than wet specimens, they praised 3DPMs for their ability to demonstrate topographical relationships between the arterial supply and adjacent structures. The data further suggested that the biggest limitation of the 3DPMs was their simplicity, thus making it more difficult for users to recognize the equivalent structures on the wet specimens. It was concluded that future designs of 3DPMs will need to consider the balance between the ease of visualization of anatomical structures and the degree of complexity required for successful transfer of learning. Overall, this study presented some conflicting evidence of the favorable outcomes of 3DPMs reported in other similar studies. While effective for anatomy learning as a standalone modality, educators must identify the position 3DPM models hold relative to other modalities in the continuum of undergraduate anatomy education in order to maximize their advantages for students.

One-lung ventilation with a bronchial blocker in thoracic patients

BackgroundLung isolation is a technique used in a multitude of surgeries to ensure single-lung ventilation with collapse of the contralateral lung, as to achieve improved access and visualization of relevant anatomical structures. Despite being accepted and having favorable outcomes, bronchial blockers (BBs) are not to this day the main device of choice among anaesthesiologists.MethodsIn this retrospective and descriptive study, we analyzed the safety and efficacy of a BB in all types of thoracic surgeries in our centre between 2015 and 2022, excluding patients with massive hemoptysis or empyema, or who had undergone a prior pneumonectomy.ResultsOne hundred and thirty-four patients were intervened due to lung cancer (67.9%), respiratory disease (23.9%), and non-respiratory disease (8.2%) undergoing lung surgeries (65.7%), pleural and mediastinal surgeries (29.9%), chest wall surgeries (3.0%) and other surgeries (1.5%). In most cases, lung collapse was considered excellent (63.9%) or good (33.1%) with only 4 cases (3.0%) of poor lung collapse. More than 90% of patients did not present intraoperative or immediate postoperative complications. No statistically significant differences were found between lung collapse and the demographic, clinical or BB-related variables (p > 0.05). However, we found a significatively higher proportion of excellent lung collapses in VATS surgeries and lateral decubitus positioning, as well as a significatively less proportion of poor lung collapses (p < 0.05). Moreover, there was a significantly higher proportion of excellent lung collapses when the BB was placed in the left bronchus (p < 0.05).ConclusionsWith these results, in our experience BBs constitute an effective alternative, capable of achieving pulmonary collapse in all kinds of thoracic procedures with satisfactory safety rates due to their minimal complications.

MD-Cave: An Immersive Visualization Workbench for Radiologists.

The MD-Cave is an immersive analytics system that provides enhanced stereoscopic visualizations to support visual diagnoses performed by radiologists. The system harnesses contemporary paradigms in immersive visualization and 3D interaction, which are better suited for investigating 3D volumetric data. We retain practicality through efficient utilization of desk space and comfort for radiologists in terms of frequent long duration use. MD-Cave is general and incorporates: (1) high resolution stereoscopic visualizations through a surround triple-monitor setup, (2) 3D interactions through head and hand tracking, (3) and a general framework that supports 3D visualization of deep-seated anatomical structures without the need for explicit segmentation algorithms. Such a general framework expands the utility of our system to many diagnostic scenarios. We have developed MD-Cave through close collaboration and feedback from two expert radiologists who evaluated the utility of MD-Cave and the 3D interactions in the context of radiological examinations. We also provide evaluation of MD-Cave through case studies performed by an expert radiologist and concrete examples on multiple real-world diagnostic scenarios, such as pancreatic cancer, shoulder-CT, and COVID-19 Chest CT examination.

Study of the Use of AI (Artificial Intelligence) in the Field of Radiology and Imaging

AI is used to automate medical image processing. These include image normalization, image quality improvement, and noise reduction, all of which can improve visualization of anatomical structures and lesions. AI is used to detect lesions or pathological changes in medical images, such as tumors, blood clots, or malformations. This can help doctors in early diagnosis and more effective treatment. AI can help in identifying and marking specific areas in medical images, such as organs, tumors, or blood vessels. The literature search process was carried out on various databases (PubMed, Web of Sciences, EMBASE, Cochrane Libraries, and Google Scholar) regarding the potential of AI in the field of radiology and imaging. This study follows the preferred reporting items for systematic reviews and meta-analysis (PRISMA) recommendations. In radiology and imaging, the use of artificial intelligence (AI) has had a significant and diverse impact. AI helps improve diagnostic capabilities by detecting and characterizing lesions, pathological changes, and anomalies in medical images, including tumors, blood clots, or malformations. AI automates tasks such as image normalization, quality improvement, noise reduction, and segmentation, allowing radiologists and physicians to work faster and obtain more accurate results.

High-Definition 3D Exoscope in Pediatric Otorhinolaryngology: A Systematic Literature Review.

Search criteria were applied to PubMed, EMBASE and the Cochrane Review databases and included all studies published up to January 2023 reporting 3D 4K exoscope-assisted surgeries in pediatric patients. After the removal of duplicates, selection of abstracts and full-text articles, and quality assessment, we reviewed eligible articles for number of patients treated, age, surgical procedures, and outcomes. Among 54 potentially relevant records, 5 studies were considered eligible and included in this systematic review, with reported treatment data for 182 patients. The surgical procedures belong to the otologic field (121 cases), head and neck surgery (25 cases) and transoral surgery (36 cases). Exoscopy allowed high quality visualization of anatomical structures during cochlear implantation and during reconstruction in head and neck surgery; moreover, it improved the surgical view of surgeons, spectators and ENT students. The use of 3D 4K exoscopy has shown promising potential as a valuable tool in pediatric ORL-head and neck surgery; nevertheless, further validation of these encouraging outcomes is necessary through larger-scale studies specifically focused on pediatric patients.

4D-DSA for Assessment of the Angioarchitecture and Grading of Cranial Dural AVF.

Time-resolved 3D rotational angiography (4D-DSA) has been used to demonstrate details of the angioarchitecture of AVM, whereas it has rarely been used to describe features of dural AVF. In this exploratory study, we analyzed dural AVFs with a novel 4D software prototype, developed and provided by Siemens, to determine whether identification of the location of the fistulous point, grading, and treatment planning were feasible. 4D-DSA volumes were calculated from existing 3D rotational angiography data sets of patients with dural AVFs. The 4D-DSA volumes were displayed in a virtual DSA mode and MPR or MIP in 3 orthogonal planes and compared with 2D-DSA by 2 experienced neuroradiologists. Fusions with unenhanced CT or MR images were used to improve visualization of adjacent anatomic structures. Comparison with 2D-DSA showed that evaluation of the fistulous point and grading according to the classification of Borden, Cognard, or Barrow was feasible in 26 of 27 cases. In 8 of 27 cases, 4D-DSA was considered advantageous for determining the fistulous point and the course of the draining vein in the dural AVF with cortical venous drainage, especially in the frontoethmoidal and frontoparietal regions. In 6 cases, the display of angioarchitecture was considered inferior to that of 2D-DSA due to motion artifacts, suboptimal selection of the injected vessel, and lack of temporal resolution. Detailed analysis of dural AVFs according to the standardized display of 4D-DSA volumes was feasible and helpful in understanding the angioarchitecture in selected cases. Further improvement and validation of the 4D software should solidify the complementary role of 4D-DSA to conventional 2D-DSA series.

Expanding the toolset of fluorescent covalent staining of biological samples by labeling carboxylate and phosphate groups.

Recently, fluorescent covalent staining methods have been developed for visualization of anatomical structures in cells and tissues. Coupled with expansion microscopy, these stains revealed various ultrastructural details. However, the covalently stainable chemical groups have been limited to amines, carbohydrates, and thiols. Here, we developed procedures for covalently labeling tissues for carboxylate and phosphate groups, utilizing carbodiimide crosslinker chemistry. In porcine kidney tissues, the carboxylate and phosphate stain provides 1.8-4.8-fold higher signal intensity than those from the three existing stains. In cancer cells, such stain allows 2-8-fold more accurate identification of nucleoli than the amine stain. In expansion microscopy samples, such stain reveals a variety of sub-cellular structures in tissues when combined with the amine stain. Such stain also allows imaging of lipid-based structures in cultured cells. With these advantages, this new covalent staining method further expands the toolset for fluorescent visualization of histology.