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The Usefulness of Dual-Volume Visualization (Three-Dimensional Digital Subtraction Angiography and Cross-Sectional Imaging) for Surgical Planning in Treating Intracranial Meningiomas: A Case Series and Technical Report
摘要： In presurgical planning for intracranial meningiomas, the relationship between tumors and adjacent vasculature must be identified. The purpose of this study was to evaluate the usefulness of 3-dimensional digital subtraction angiography (3D-DSA) with dual-volume visualization (DVV). Between February 2013 and April 2016, 26 patients with intracranial meningiomas enrolled in this study. Two or 3 days before surgery, 3D-DSA with DVV was performed for presurgical planning. If necessary, the tumor was simultaneously embolized. Vascular supply and disfiguration observed by preoperative 3D-DSA with DVV closely resembled those actually observed during surgery. All but 2 patients had total tumor resection (Simpson grade 1 or 2). Three of 26 patients had new neurologic deficits. 3D-DSA with DVV may be useful for preoperative planning by allowing the surgeon to identify the relationship between a tumor and peritumoral vasculature before meningioma surgery. Young neurosurgeons with little experience may benefit most from this technique.
关键词： Meningioma,Digital subtraction angiography,Three-dimensional imaging,Computer-assisted surgery
更新于2025-09-23 15:23:52
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New Parametric Imaging Method with Fluorescein Angiograms for Detecting Areas of Capillary Nonperfusion
摘要： Fluorescein angiography (FAG) is currently the most useful diagnostic modality for examining retinal circulation, and it is frequently used for the evaluation of patients with diabetic retinopathy, occlusive diseases, such as retinal venous and arterial occlusions, and wet macular degeneration. This paper presents a method for objectively evaluating retinal circulation by quantifying circulation-related parameters. Methods: This method allows the semiautomatic preprocessing and registering of FAG images. The arterial input function is estimated from the registered set of FAG images using gamma-variate fitting. Then, the parameters can be computed by deconvolution on the basis of truncated singular value decomposition, and they can finally be presented as parametric color images in a combination of three colors, red, green, and blue. Results: After the estimation of arterial input function, the parameters of relative blood flow and mean transit time were computed using deconvolution analysis based on truncated singular value decomposition. Conclusions: The parametric color image is helpful to interpret the status of retinal blood circulation and provides quantitative data on retina ischemia without interobserver variability. This system easily provides the status of retinal blood circulation both qualitatively and quantitatively. It also helps to standardize FAG interpretation and may contribute to network-based telemedicine systems in the future.
关键词： Fluorescein Angiography,Ophthalmology,Computer-Assisted Diagnosis,Eye Disease,Biomedical Engineering
更新于2025-09-23 15:22:29
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Assessment of CT numbers in limited and medium field-of-view scans taken using Accuitomo 170 and Veraviewepocs 3De cone-beam computed tomography scanners
摘要： Purpose: To assess the influence of anatomic location on the relationship between computed tomography (CT) number and X-ray attenuation in limited and medium field-of-view (FOV) scans. Materials and Methods: Tubes containing solutions with different concentrations of K2HPO4 were placed in the tooth sockets of a human head phantom. Cone-beam computed tomography (CBCT) scans were acquired, and CT numbers of the K2HPO4 solutions were measured. The relationship between CT number and K2HPO4 concentration was examined by linear regression analyses. Then, the variation in CT number according to anatomic location was examined. Results: The relationship between K2HPO4 concentration and CT number was strongly linear. The slopes of the linear regressions for the limited FOVs were almost 2-fold lower than those for the medium FOVs. The absolute CT number differed between imaging protocols and anatomic locations. Conclusion: There is a strong linear relationship between X-ray attenuation and CT number. The specific imaging protocol and anatomic location of the object strongly influence this relationship.
关键词： Image Processing, Computer-Assisted,Imaging, Three-Dimensional,Cone-Beam Computed Tomography
更新于2025-09-23 15:22:29
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Performance of Cone Beam Computed Tomography Systems in Visualizing the Cortical Plate in 3D Image Reconstruction: An Study
摘要： Introduction: Cortical bone is an important anatomical structure and its thickness needs to be determined prior to many dental procedures to ensure treatment success. Imaging modalities are necessarily used in dentistry for treatment planning and dental procedures. Three-dimensional image reconstruction not only provides visual information but also enables accurate measurement of anatomical structures; thus, it is necessarily required for maxillofacial examination and in case of skeletal problems in this region. Aims: This study aimed to assess the ability of three Cone Beam Computed Tomography (CBCT) systems including Cranex 3D, NewTom 3G and 3D Promax for Three-Dimensional (3D) image reconstruction of the cortical plate with variable thicknesses. Methods: Depending on the cortical bone thickness, samples were evaluated in three groups of ≤ 0.5 mm, 0.6 -1 mm and 1.1-1.5 mm cortical bone thickness. The CBCT scans were obtained from each sample using three systems, their respective FOVs, and 3D scans were reconstructed using their software programs. Two observers viewed the images twice with a two-week interval. The ability of each system in the 3D reconstruction of different thicknesses of cortical bone was determined based on its visualization on the scans. The data were analyzed using SPSS and Kappa test. Results: The three systems showed the greatest difference in the 3D reconstruction of cortical bone with < 0.5 mm thickness. Cranex 3D with 4×6 cm2 FOV had the highest and 3D Promax with 8×8 cm2 FOV had the lowest efficacy for 3D reconstruction of cortical bone. Cranex 3D with 4×6 cm2 and 6×8 cm2 FOVs and NewTom 3G with 5×5 cm2 and 8×5 cm2 FOVs showed significantly higher efficacy for 3D reconstruction of cortical bone with 0.6-1mm thickness while 3D Promax followed by NewTom 3G with 8×8 cm2 FOV had the lowest efficacy for this purpose. Conclusion: Most CBCT systems have high efficacy for 3D image reconstruction of cortical bone with thicknesses over 1 mm while they have poor efficacy for image reconstruction of cortical bone with less than 0.5 mm thickness. Thus, for accurate visualization of anatomical structures on CBCT scans, systems with smaller FOVs and consequently smaller voxel size are preferred.
关键词： Cone-Beam Computed Tomography (CBCT),Imaging,Computer-assisted,Image processing,Three-dimensional,Cortical bone
更新于2025-09-23 15:22:29
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ICRU report?91 on prescribing, recording, and reporting of stereotactic treatments with small photon beams; ICRU-Bericht 91 über die Verschreibung, Aufzeichnung und Dokumentation von stereotaktischen Behandlungen mit kleinen Photonenfeldern;
摘要： The International Commission on Radiation Units and Measurements (ICRU) report 91 with the title “prescribing, recording, and reporting of stereotactic treatments with small photon beams” was published in 2017. This extensive publication covers different relevant aspects of stereotactic radiotherapy such as small field dosimetry, accuracy requirements for volume definition and planning algorithms, and the precise application of treatment by means of image guidance. Finally, recommendations for prescribing, recording and reporting are given.
关键词： Organs at risk,Stereotactic radiotherapy,Radiotherapy planning, computer-assisted,Stereotactic body radiation therapy,Stereotactic radiosurgery
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Krakow (2018.10.16-2018.10.18)] 2018 IEEE International Conference on Imaging Systems and Techniques (IST) - Assessment of a Markerless Optical Tracking Technique for Computer-Assisted Hip Surgery
摘要： This article presents an evaluation of a prototype optical tracking system intended for use in computer-assisted orthopedic surgery. The device is based on a smartphone with a built-in video camera, and an external miniature time-of-flight camera. It is able to automatically recognize a surgical instrument based on its shape and appearance, and to determine its orientation relative to an array of light-reflective markers. The experiments were done in a measurement configuration and with the instruments that are specific to computer-assisted implantation of the acetabular component in total hip replacement surgery. The evaluation included the recognition rate of the instruments, and the angular accuracy of the system. The results show, that the accuracy is comparable to that obtained by conventional tracking devices in clinical settings, and partially meets the requirements specified in the literature for hip surgery.
关键词： optical tracking,surgical navigation,accuracy,computer assisted surgery,time of flight camera
更新于2025-09-23 15:22:29
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Multi-objective Parameter Auto-tuning for Tissue Image Segmentation Workflows
摘要： We propose a software platform that integrates methods and tools for multi-objective parameter auto-tuning in tissue image segmentation workflows. The goal of our work is to provide an approach for improving the accuracy of nucleus/cell segmentation pipelines by tuning their input parameters. The shape, size, and texture features of nuclei in tissue are important biomarkers for disease prognosis, and accurate computation of these features depends on accurate delineation of boundaries of nuclei. Input parameters in many nucleus segmentation workflows affect segmentation accuracy and have to be tuned for optimal performance. This is a time-consuming and computationally expensive process; automating this step facilitates more robust image segmentation workflows and enables more efficient application of image analysis in large image datasets. Our software platform adjusts the parameters of a nuclear segmentation algorithm to maximize the quality of image segmentation results while minimizing the execution time. It implements several optimization methods to search the parameter space efficiently. In addition, the methodology is developed to execute on high-performance computing systems to reduce the execution time of the parameter tuning phase. These capabilities are packaged in a Docker container for easy deployment and can be used through a friendly interface extension in 3D Slicer. Our results using three real-world image segmentation workflows demonstrate that the proposed solution is able to (1) search a small fraction (about 100 points) of the parameter space, which contains billions to trillions of points, and improve the quality of segmentation output by × 1.20, × 1.29, and × 1.29, on average; (2) decrease the execution time of a segmentation workflow by up to 11.79× while improving output quality; and (3) effectively use parallel systems to accelerate parameter tuning and segmentation phases.
关键词： Parameter auto-tuning,Cancer,Cell morphology,Computer-assisted image analysis,Digital pathology
更新于2025-09-23 15:21:01
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IMAGE-GUIDED SURGERY IN THE SPINE: NEURONAVIGATION VS. FLUOROSCOPY
摘要： Objectives: To evaluate the accuracy and the operative complications of implanting pedicle screws in the thoracic and lumbar spine, using computer-assisted surgery compared to the implantation technique using fluoroscopy. Methods: A retrospective study was conducted at the Hospital Universitário Cajuru PUC-PR from January 2000 to January 2009. Two groups of patients undergoing implant pedicle screws were analyzed (n=80). Group I received implant pedicle screws through fluoroscopy technique and group II, through neuronavigation technique. The accuracy of positioning of pedicle screws was evaluated using rating scales. Results: The accuracy was higher in group II, where 77.5% of the screws were correctly positioned, whereas there were only 28.5% in group I (p=0.001). There was a reduction of 95% (CI: 80-97%) in the risk of screws misplacement in group II. The average operation time was 312.2±78.1 minutes in group I and 270.3±41.4 in group II (p=0.004). Blood transfusion was needed in 28 patients in group I and 10 patients in group II (p=0.005), resulting in 64% risk reduction of blood transfusion in group II. Eight patients in group I underwent revision surgery whereas only one patient in the group II, that is, 75% of surgical revision risk reduction. Conclusion: The implantation technique of pedicle screws using neuronavigation is a more accurate method and has less operative complications compared with the technique that uses fluoroscopy.
关键词： Surgery,Spine/surgery,Neuronavigation,computer-assisted,Fluoroscopy
更新于2025-09-19 17:15:36
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Optical biopsy of penile cancer with in vivo confocal laser endomicroscopy
摘要： Introduction: Surgical management of penile cancer depends on accurate margin assessment and staging. Advanced optical imaging technologies may improve penile biopsy and organ-sparing treatment. We evaluated the feasibility of confocal laser endomicroscopy for intraoperative assessment of benign and malignant penile tissue. Patients and methods: With institutional review board approval, 11 patients were recruited, 9 with suspected penile cancer, and 2 healthy controls. Confocal laser endomicroscopy using a 2.6-mm fiber-optic probe was performed at 1 or 2 procedures on all subjects, for 13 imaging procedures. Fluorescein was administered intravenously approximately 3 minutes prior to imaging for contrast. Video sequences from in vivo (n = 12) and ex vivo (n = 6) imaging were obtained of normal glans, suspicious lesions, and surgical margins. Images were processed, annotated, characterized, and correlated with standard hematoxylin and eosin histopathology. Results: No adverse events related to imaging were reported. Distinguishing features of benign and malignant penile tissue could be identified by confocal laser endomicroscopy. Normal skin had cells of uniform size and shape, with distinct cytoplasmic membranes consistent with squamous epithelium. Malignant lesions were characterized by disorganized, crowded cells of various size and shape, lack of distinct cytoplasmic membranes, and hazy, moth-eaten appearance. The transition from normal to abnormal squamous epithelium could be identified. Conclusions: We report the initial feasibility of intraoperative confocal laser endomicroscopy for penile cancer optical biopsy. Pending further evaluation, confocal laser endomicroscopy could serve as an adjunct or replacement to conventional frozen section pathology for management of penile cancer.
关键词： Surgery,Microscopy,Confocal,Penile neoplasms,Computer-assisted
更新于2025-09-12 10:27:22
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Computer-designed selective laser sintering surgical guide and immediate loading dental implants with definitive prosthesis in edentulous patient: A preliminary method
摘要： Objective: The aim of this study was to analyze a preliminary method of immediately loading dental implants and a definitive prosthesis based on the computer?aided design/computer?aided manufacturing systems, after 2 years of clinical follow?up. Materials and Methods: The study comprised one patient in good general health with edentulous maxilla. Cone beam computer tomography (CBCT) was performed using a radiographic template. The surgical plan was made using the digital imaging and communications in medicine protocol with ImplantViewer (version 1.9, Anne Solutions, Sao Paulo, SP, Brazil), the surgical planning software. These data were used to produce a selective laser sintering surgical template. A maxilla prototype was used to guide the prosthesis technician in producing the prosthesis. Eight dental implants and a definitive prosthesis were installed on the same day. A post?operative CBCT image was fused with the image of the surgical planning to calculate the deviation between the planned and the placed implants positions. Patient was followed for 2 years. Results: On average, the match between the planned and placed angular deviation was within 6.0 ± 3.4° and the difference in coronal deviation was 0.7 ± 0.3 mm. At the end of the follow?up, neither the implant nor the prosthesis was lost. Conclusions: Considering the limited samples number, it was possible to install the dental implants and a definitive prosthesis on the same day with success.
关键词： immediate loading dental implant,Computer-assisted surgery,dental implants
更新于2025-09-11 14:15:04