Image-guided System Research Articles

Percutaneous sacroiliac screw fixation with a 3D robot-assisted image-guided navigation system

Abstract Objective Presentation and description of percutaneous sacroiliac (SI) screw fixation with the use of a 3D robot-assisted image-guided navigation system and the clinical outcome of this technique. Indications Pelvic fractures involving the posterior pelvis. Contraindications Patients not suited for surgery. Surgical technique Planning the screws on the diagnostic computer tomogram (CT). Matching with a low-dose CT in the operating room. Lateral incision. Verify the guidewire position with the personalized inlet and outlet views. After correct positioning, place a cannulated screw over the guidewire. For fragility fractures, augmentation is recommended. Finish the surgery with a final 3D scan to confirm correct placement of the screws and cement. Postoperative management Direct postoperative mobilization with pain-adapted full weight-bearing. Results Data of 141 patients between January 2018 and August 2022 were analyzed (average age 82 ± 10 years, 89% female). Most of the fractures were type II fragility fractures of the pelvis (FFP; 75%). The median hospital stay was 12 ± 7 days and the median surgery duration for a unilateral SI screw was 26 min. In total 221 S1 screws and 17 S2 screws were applied. No screws showed signs of loosening or migration. Of the five suboptimally placed screws, one screw was removed due to sensory impairment. All patients with cement leakage remained without symptoms. Conclusion The surgical technique with the use of a 3D robot-assisted image-guided navigation system is a technique for safe fixation of dorsal fragility fractures of the pelvis and is associated with fewer complications.

Quantification of uncertainties in reference and relative dose measurements, dose calculations, and patient setup in modern external beam radiotherapy.

Uncertainties in the steps of external beam radiotherapy (EBRT) affect patient outcomes. However, few studies have investigated major contributors to these uncertainties. This study investigated factors contributing to reducing uncertainty in delivering a dose to a target volume. The EBRT process was classified into four steps: reference dosimetry, relative dosimetry [percentage depth doses (PDDs) and off-center ratios (OCRs)], dose calculations (PDDs and OCRs in a virtual water phantom), and patient setup using an image-guided radiation therapy system. We evaluated the uncertainties for these steps in conventionally fractionated EBRT for intracranial disease using 4-, 6-, and 10-MV flattened photon beams generated from clinical linear accelerators following the Guide to the Expression of Uncertainty in Measurement and an uncertainty evaluation method with uncorrected deflection. The following were the major contributors to these uncertainties: beam quality conversion factors for reference dosimetry; charge measurements, chamber depth, source-to-surface distance, water evaporation, and field size for relative dosimetry; dose calculation accuracy for the dose calculations; image registration, radiation-imaging isocenter coincidence, variation in radiation isocenter due to gantry and couch rotation, and intrafractional motion for the patient setup. Among the four steps, the relative dosimetry and dose calculation (namely, both penumbral OCRs) steps involved an uncertainty of more than 5% with a coverage factor of 1. In the EBRT process evaluated herein, the uncertainties in the relative dosimetry and dose calculations must be reduced.

Progress in neurosurgical treatment of neurofibromatosis type 1

To summarize the latest developments in neurosurgical treatments for neurofibromatosis type 1 (NF1) and explore therapeutic strategies to provide comprehensive treatment guidelines for clinicians. The recent domestic and international literature and clinical cases in the field of NF1 were reviewed. The main types of neurological complications associated with NF1 and their treatments were thorough summarized and the future research directions in neurosurgery was analyzed. NF1 frequently results in complex and diverse lesions in the central and peripheral nervous systems, particularly low-grade gliomas in the brain and spinal canal and paraspinal neurofibromas. Treatment decisions should be made by a multidisciplinary team. Symptomatic plexiform neurofibromas and tumors with malignant imaging evidence require neurosurgical intervention. The goals of surgery include reducing tumor size, alleviating pain, and improving appearance. Postoperative functional rehabilitation exercises, long-term multidisciplinary follow-up, and psychosocial interventions are crucial for improving the quality of life for patients. Advanced imaging guidance systems and artificial intelligence technologies can help increase tumor resection rates and reduce recurrence. Neurosurgical intervention is the primary treatment for symptomatic plexiform neurofibromas and malignant peripheral nerve sheath tumors when medical treatment is ineffective and the lesions progress rapidly. Preoperative multidisciplinary assessment, intraoperative electrophysiological monitoring, and advanced surgical assistance devices significantly enhance surgical efficacy and safety. Future research should continue to explore new surgical techniques and improve postoperative management strategies to achieve more precise and personalized treatment for NF1 patients.

Computed tomography and structured light imaging guided orthopedic navigation puncture system: effective reduction of intraoperative image drift and mismatch.

Image-guided surgical navigation systems are widely regarded as the benchmark for computer-assisted surgical robotic platforms, yet a persistent challenge remains in addressing intraoperative image drift and mismatch. It can significantly impact the accuracy and precision of surgical procedures. Therefore, further research and development are necessary to mitigate this issue and enhance the overall performance of these advanced surgical platforms. The primary objective is to improve the precision of image guided puncture navigation systems by developing a computed tomography (CT) and structured light imaging (SLI) based navigation system. Furthermore, we also aim to quantifying and visualize intraoperative image drift and mismatch in real time and provide feedback to surgeons, ensuring that surgical procedures are executed with accuracy and reliability. A CT-SLI guided orthopedic navigation puncture system was developed. Polymer bandages are employed to pressurize, plasticize, immobilize and toughen the surface of a specimen for surgical operations. Preoperative CT images of the specimen are acquired, a 3D navigation map is reconstructed and a puncture path planned accordingly. During surgery, an SLI module captures and reconstructs the 3D surfaces of both the specimen and a guiding tube for the puncture needle. The SLI reconstructed 3D surface of the specimen is matched to the CT navigation map via two-step point cloud registrations, while the SLI reconstructed 3D surface of the guiding tube is fitted by a cylindrical model, which is in turn aligned with the planned puncture path. The proposed system has been tested and evaluated using 20 formalin-soaked lower limb cadaver specimens preserved at a local hospital. The proposed method achieved image registration RMS errors of 0.576 ± 0.146 mm and 0.407 ± 0.234 mm between preoperative CT and intraoperative SLI surface models and between preoperative and postoperative CT surface models. In addition, preoperative and postoperative specimen surface and skeletal drifts were 0.033 ± 0.272 mm and 0.235 ± 0.197 mm respectively. The results indicate that the proposed method is effective in reducing intraoperative image drift and mismatch. The system also visualizes intraoperative image drift and mismatch, and provides real time visual feedback to surgeons.

Imaging-Guided Classification of Neovascularization in Neovascular Age-Related Macular Degeneration: Progress to Date.

Purpose: To review the evolution of terminology describing the classification of lesions in neovascular age-related macular degeneration (nAMD) based on retinal imaging technologies. Methods: A review of the current and historical literature on imaging-guided classification of neovascularization in nAMD was performed. Results: Imaging-guided classification of neovascularization in nAMD facilitates understanding of the pathological mechanisms and disease progression. Neovascularization classification has evolved with advances in imaging technologies, from earlier classifications based on neovascularization patterns assessed by fluorescein angiography to multimodal imaging patterns, resulting in varied descriptions of lesions depending on the techniques used. Until recently, there has been a lack of consensus regarding the clinical features of choroidal neovascularization lesion types as a result of the imaging modalities initially used to define them; a recent consensus on classification has the potential to simplify and clarify descriptions of neovascularization in nAMD. The use of multimodal imaging techniques will improve lesion identification and has the potential to individualize treatment plans and improve outcomes. Conclusions: Widespread adoption of a consensus-based, image-guided classification system for neovascular lesions in nAMD and the appropriate imaging techniques used to identify them will aid clinical research and could potentially improve patient outcomes by individualizing treatment plans in the future.

Characterization of kilovoltage x-ray image guidance system with a novel post-processing algorithm on a new slip ring-mounted radiotherapy system.

This study evaluates the performance of a kilovoltage x-ray image-guidance system equipped with a novel post-processing optimization algorithm on the newly introduced TAICHI linear accelerator (Linac). A comparative study involving image quality tests and radiation dose measurements was conducted across six scanning protocols of the kV-cone beam computed tomography (CBCT) system on the TAICHI Linac. The performance assessment utilized the conventional Feldkamp-Davis-Kress (FDK) algorithm and a novel Non-Local Means denoising and adaptive scattering correction (NLM-ASC) algorithm. Image quality metrics, including spatial resolution, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR), were evaluated using a Catphan 604 phantom. Radiation doses for low-dose and standard protocols were measured using a computed tomography dose index (CTDI) phantom, with comparative measurements from the Halcyon Linac's iterative CBCT (iCBCT). The NLM-ASC algorithm significantly improved image quality, achieving a 300%-1000% increase in CNR and SNR over the FDK-only images and it also showed a 100%-200% improvement over the iCBCT images from Halcyon's head protocol. The optimized low-dose protocols yielded higher image quality than the standard FDK protocols, indicating potential for reduced radiation exposure. Clinical implementation confirmed the TAICHI system's utility for precise and adaptive radiotherapy. The kV-IGRT system on the TAICHI Linac, with its novel post-processing algorithm, demonstrated superior image quality suitable for routine clinical use, effectively reducing image noise without compromising other quality metrics.

From Coarse to Fine: Non-Rigid Sparse-Dense Registration for Deformation-Aware Liver Surgical Navigation.

Intraoperative liver deformation poses a considerable challenge during liver surgery, causing significant errors in image-guided surgical navigation systems. This study addresses a critical non-rigid registration problem in liver surgery: the alignment of intrahepatic vascular trees. The goal is to deform the complete vascular shape extracted from preoperative Computed Tomography (CT) volume, aligning it with sparse vascular contour points obtained from intraoperative ultrasound (iUS) images. Challenges arise due to the intricate nature of slender vascular branches, causing existing methods to struggle with accuracy and vascular self-intersection. We present a novel non-rigid sparse-dense registration pipeline structured in a coarse-to-fine fashion. In the initial coarse registration stage, we introduce a parametrization deformation graph and a Welsch function-based error metric to enhance convergence and robustness of non-rigid registration. For the fine registration stage, we propose an automatic curvature-based algorithm to detect and eliminate overlapping regions. Subsequently, we generate the complete vascular shape using posterior computation of a Gaussian Process Shape Model. Experimental results using simulated data demonstrate the accuracy and robustness of our proposed method. Evaluation results on the target registration error of tumors highlight the clinical significance of our method in tumor location computation. Comparative analysis against related methods reveals superior accuracy and competitive efficiency of our approach. Moreover, Ex vivo swine liver experiments and clinical experiments were conducted to evaluate the method's performance. The experimental results itasize the accurate and robust performance of our proposed method. Our proposed non-rigid registration method holds significant application potential in clinical practice.

Resident Opinions on Image Guidance for External Ventricular Drain Placement: A National Survey

BACKGROUND AND OBJECTIVES: Low-quality data on image-guided external ventricular drain (EVD) accuracy are in large part due to a lack of widespread usage of this system for EVD placement. The potential disconnect between user preferences and existing technologies should be explored to guide future developments. The goal of this study was to survey neurosurgical residents regarding their EVD practices and determine the acceptable amount of setup time for an ideal neuronavigation system. METHODS: A 4-question survey was sent to approximately 1512 residents at 108 Acreditation Council for Graduate Medical Education–approved medical doctor neurosurgical training programs in the United States. The responses were received electronically, tabulated, and analyzed using descriptive statistics. RESULTS: A total of 130 respondents (9%) completed the survey, reflecting the highest number of neurosurgical resident respondents in an electronic qualitative survey of EVD practices thus far. Residents were willing to accept 6.39 min (SD = 3.73 min) on average for the setup of a bedside EVD image guidance system. The majority chose to use image guidance during EVD placement for cases of narrow slit-like ventricles (86.92%) over intraventricular hemorrhage (13.08%) and hydrocephalus (0%). A total of 90% of all resident respondents misplaced at least 1 EVD with 74% of post-graduate year–7 respondents misplacing more than 3 EVDs in their career. A total of 88.46% of respondents deemed more than a single pass as acceptable. CONCLUSION: Future EVD neuronavigation technologies should focus on achieving rapid registration times. These systems may be prioritized for patients with anatomic distortions. Current resident attitudes are accepting multiple EVD passes, likely because of the inherent limitations of the traditional freehand approach. Efforts should be made to encourage the best course for the patient.

A Network Meta-Analysis Comparing the Efficacy and Safety of Pedicle Screw Placement Techniques Using Intraoperative Conventional, Navigation, Robot-Assisted, and Augmented Reality Guiding Systems.

Studies were reviewed and collected to compare different image guidance systems for pedicle screw placement (PSP) regarding accuracy and safety outcomes. Included were conventional, navigation, robot-assisted, and recent technology such as augmented reality (AR) guiding systems. This network meta-analysis obtained human comparative studies and randomized controlled trials (RCTs) regarding PSP found in 3 databases (Cochrane, PubMed, and Scopus). Data extraction for accuracy, safety, and clinical outcomes were collected. The network meta-analysis was analyzed, and a surface under the cumulative ranking curve (SUCRA) was used to rank the treatment for all outcomes. The final 61 studies, including 13 RCTs and 48 non-RCTs, were included in the meta-analysis. These studies included a total of 17,023 patients and 35,451 pedicle screws. The surface under the cumulative ranking curve ranking demonstrated the supremacy of robotics in almost all accuracy outcomes except for the facet joint violation. Regarding perfect placement, the risk difference for AR was 19.1 (95% CI: 8.1-30.1), which was significantly higher than the conventional method. The robot-assisted and navigation systems had improved outcomes but were not significantly different in accuracy vs the conventional technique. There was no statistically significant difference concerning safety or clinical outcomes. The accuracy of PSP achieved by robot-assisted technology was the highest, whereas the safety and clinical outcomes of the different methods were comparable. The recent AR technique provided better accuracy compared with navigation and conventional methods.

Comprehensive stereotactic radiosurgery platform characterization: A novel end-to-end approach with anthropomorphic 3D dosimetry.

Stereotactic radiosurgery (SRS) is a widely employed strategy for intracranial metastases, utilizing linear accelerators and volumetric modulated arc therapy (VMAT). Ensuring precise linear accelerator performance is crucial, given the small planning target volume (PTV) margins. Rapid dose falloff is vital to minimize brain radiation necrosis. Despite advances in SRS planning, tools for end-to-end testing of SRS treatments are lacking, hindering confidence in the procedure. This study introduces a novel end-to-end three-dimensional (3D) anthropomorphic dosimetry system for characterization of a radiosurgery platform, aiming to measure planning metrics, dose gradient index (DGI), brain volumes receiving at least 10 and 12Gy (V10, V12), as well as assess delivery uncertainties in multitarget treatments. The study also compares metrics from benchmark plans to enhance understanding and confidence in SRS treatments. The developed anthropomorphic 3D dosimetry system includes a modified Stereotactic End-to-End Verification (STEEV) phantom with a customized insert integrating 3D dosimeters and a fiber optic CT scanner. Labview and MATLAB programs handle optical scanning, image preprocessing, and dosimetric analysis. SlicerRT is used for 3D dose visualization and analysis. A film stack insert was used to validate the 3D dosimeter measurements at specific slices. Benchmark plans were developed and measured to investigate off-axis errors, dose spillage, small field dosimetry, and multi-target delivery. The accuracy of the developed 3D dosimetry system was rigorously assessed using radiochromic films. Two two-dimensional (2D) dose planes, extracted from the 3D dose distribution, were compared with film measurements, resulting in high passing rates of 99.9% and 99.6% in gamma tests. The mean relative dose difference between film and 3D dosimeter measurements was -1%, with a standard deviation of 2.2%, well within dosimeter uncertainties. In the first module, evaluating single-isocenter multitarget treatments, a 1.5mm dose distribution shift was observed when targets were 7cm off-axis. This shift was attributed to machine mechanical errors and image-guided system uncertainties, indicating potential limitations in conventional gamma tests. The second module investigated discrepancies in intermediate-to-low dose spillage, revealing higher measured doses in the connecting region between closely positioned targets. This discrepancy was linked to uncertainties in treatment planning system (TPS) modeling of out-of-field dose and multileaf collimator (MLC) characteristics, resulting in lower DGI values and higher V10 and V12 values compared to TPS calculations. In the third module, irradiating multiple targets showed consistent V10 and V12 values within 1 cm3 agreement with dose calculations. However, lower DGI values from measurements compared to calculations suggested intricacies in the treatment process. Conducting vital end-to-end testing demonstrated the anthropomorphic 3D dosimetry system's capacity to assess overall treatment uncertainty, offering a valuable tool for enhancing treatment accuracy in radiosurgery platforms. The study introduces a novel anthropomorphic 3D dosimetry system for end-to-end testing of a radiosurgery platform. The system effectively measures plan quality metrics, captures mechanical errors, and visualizes dose discrepancies in 3D space. The comprehensive evaluation capability enhances confidence in the commissioning and verification process, ensuring patient safety. The system is recommended for commissioning new radiosurgery platforms and remote auditing of existing programs.

Towards overcoming barriers to the clinical deployment of mixed reality image-guided navigation systems supporting percutaneous ablation of liver focal lesions

In recent years, we have observed a rise in the popularity of minimally invasive procedures for treating liver tumours, with percutaneous thermoablation being one of them, conducted using image-guided navigation systems with mixed reality technology. However, the application of this method requires adequate training in using the employed system. In our study, we assessed which skills pose the greatest challenges in performing such procedures. The article proposes a training module characterized by an innovative approach: the possibility of practicing the diagnosis, planning, execution stages and the physical possibility of performing the execution stage on the radiological phantom of the abdominal cavity. The proposed approach was evaluated by designing a set of 4 exercises corresponding to the 3 phases mentioned. To the research group included 10 radiologists and 5 residents in the study. Based on 20 clinical cases of liver tumors subjected to percutaneous thermoablation, we developed assessment tasks evaluating four skill categories: head-mounted display (HMD), ultrasound (US)/computed tomography (CT) image fusion interpretation, tracking system use, and the ability to insert a needle. The results were presented using the Likert scale. The results of our study indicate that the most challenging aspect for radiology specialists is adapting to HMD gesture control, while residents point to intraoperative images of fusion and respiratory movements in the liver as the most problematic. In terms of improving the ability to perform procedures on new patients, the module also allows you to create a new hologram for a different clinical case.

Intraoperative Image Guidance in Orbital and Lacrimal Surgery: A Report by the American Academy of Ophthalmology

To review the efficacy and safety of the use of intraoperative image guidance (IIG) in orbital and lacrimal surgery. A literature search of the PubMed database was last conducted in November 2023 for English-language original research that assessed the use of any image guidance system in orbital and lacrimal surgery that included at least 5 patients. The search identified 524 articles; 94 were selected for full-text analysis by the panel. A total of 32 studies met inclusion criteria. The panel methodologist assigned a level II rating to 2 studies and a level III rating to 30 studies. No study met the criteria for level I evidence. Procedures reported on were as follows: fracture repair (n= 14), neoplasm and infiltrate biopsy or excision (n= 6), orbital decompression for Graves ophthalmopathy (n= 3), dacryocystorhinostomy (n= 1), and mixed etiology and procedures (n= 8). Four studies used more than one IIG system. One study that met level II evidence criteria compared the outcomes of orbital fracture repair with IIG (n= 29) and without IIG (n= 29). Borderline better outcomes were reported in the IIG group: 2% versus 10% with diplopia (P= 0.039) and 3% versus 10% with enophthalmos (P= 0.065). The other level II study compared the repair of fractures with navigation (n= 20) and without (n= 20). The group in which navigation was used had a measured mean volume reduction of 3.82 cm3 compared with 3.33 cm3 (P= 0.02), and there was a greater measured reduction in enophthalmos in the navigation group of 0.72 mm (P= 0.001). Although the remaining 30 assessed articles failed to meet level II criteria, all alleged a benefit from IIG. No complications were reported. A small number of comparative studies suggest that there are improved outcomes when IIG is used in orbital fracture repair, but each study suffers from various limitations. No high-quality comparative studies exist for the management of lacrimal surgery, neoplastic disease, or decompression. Complications attributable to the use of IIG have not been identified, and IIG has not been analyzed for cost savings. Proprietary or commercial disclosure may be found after the references.

A Label-Efficient Framework for Automated Sinonasal CT Segmentation in Image-Guided Surgery.

Segmentation, the partitioning of patient imaging into multiple, labeled segments, has several potential clinical benefits but when performed manually is tedious and resource intensive. Automated deep learning (DL)-based segmentation methods can streamline the process. The objective of this study was to evaluate a label-efficient DL pipeline that requires only a small number of annotated scans for semantic segmentation of sinonasal structures in CT scans. Retrospective cohort study. Academic institution. Forty CT scans were used in this study including 16 scans in which the nasal septum (NS), inferior turbinate (IT), maxillary sinus (MS), and optic nerve (ON) were manually annotated using an open-source software. A label-efficient DL framework was used to train jointly on a few manually labeled scans and the remaining unlabeled scans. Quantitative analysis was then performed to obtain the number of annotated scans needed to achieve submillimeter average surface distances (ASDs). Our findings reveal that merely four labeled scans are necessary to achieve median submillimeter ASDs for large sinonasal structures-NS (0.96 mm), IT (0.74 mm), and MS (0.43 mm), whereas eight scans are required for smaller structures-ON (0.80 mm). We have evaluated a label-efficient pipeline for segmentation of sinonasal structures. Empirical results demonstrate that automated DL methods can achieve submillimeter accuracy using a small number of labeled CT scans. Our pipeline has the potential to improve pre-operative planning workflows, robotic- and image-guidance navigation systems, computer-assisted diagnosis, and the construction of statistical shape models to quantify population variations. N/A.

Impact of advanced image-guided systems on correction of corneal astigmatism during FLACS.

To determine the effectiveness of the correction of corneal astigmatism using the Alcon Image Guidance (IG) system vs manual marking in the orientation of femtosecond laser-assisted cataract surgery (FLACS). Private practice, Albany, New York. Retrospective review. Patients who underwent FLACS with IG and without IG were from January 2018 to June 2022 investigated. Variables including preoperative keratometry values, cylinder, spherical equivalent (SE), and visual acuity (VA) were collected, as well as the cyclorotation angle delta registered by IG, postoperative refractive cylinder, SE, and VA. The primary outcome was postoperative refractive cylinder in patients with IG compared with those without IG. A total of 160 eyes were included, with 103 eyes that had IG and 57 eyes that did not have IG. Postoperative cylinder was similar in those with IG (0.31 ± 0.36 diopters [D]) compared with those without IG (0.31 ± 0.37 D) ( P = .97). Average cyclorotation in the IG group was 2.82 ± 3.03 degrees. When cyclorotation was stratified into 3 groups (<2.8 degrees, 2.8 to 8.5 degrees, >8.5 degrees), no differences were found in postoperative refractive cylinder ( P = .35). Patients who underwent FLACS with IG had similar postoperative cylinder outcomes compared with those without IG. This study suggests that the accommodation of cyclotorsion using an advanced IG system is similar to that obtained with manual marking techniques in patients having 2 D or less of astigmatism corrected.

Non-rigid scene reconstruction of deformable soft tissue with monocular endoscopy in minimally invasive surgery.

The utilization of image-guided surgery has demonstrated its ability to improve the precision and safety of minimally invasive surgery (MIS). Non-rigid scene reconstruction is a challenge in image-guided system duo to uniform texture, smoke, and instrument occlusion, etc. METHODS: In this paper, we introduced an algorithm for 3D reconstruction aimed at non-rigid surgery scenes. The proposed method comprises two main components: firstly, the front-end process involves the initial reconstruction of 3D information for deformable soft tissues using embedded deformation graph (EDG) on the basis of dual quaternions, enabling the reconstruction without the need for prior knowledge of the target. Secondly, the EDG is integrated with isometric nonrigid structure from motion (Iso-NRSFM) to facilitate centralized optimization of the observed map points and camera motion across different time instances in deformable scenes. For the quantitative evaluation of the proposed method, we conducted comparative experiments with both synthetic datasets and publicly available datasets against the state-of-the-art 3D reconstruction method, DefSLAM. The test results show that our proposed method achieved a maximum reduction of 1.6mm in average reconstruction error compared to method DefSLAM across all datasets. Additionally, qualitative experiments were performed on video scene datasets involving surgical instrument occlusions. Our method proved to outperform DefSLAM on both synthetic datasets and public datasets through experiments, demonstrating its robustness and accuracy in the reconstruction of soft tissues in dynamic surgical scenes. This success highlights the potential clinical application of our method in delivering surgeons with critical shape and depth information for MIS.

2264: Validation of a dedicated surface- and image-guidance system for breast deep inspiration breath hold

2264: Validation of a dedicated surface- and image-guidance system for breast deep inspiration breath hold

SlicerPIT: software development and implementation for planning and image-guided therapy in photoimmunotherapy.

Photoimmunotherapy is a treatment modality that induces targeted cell death by binding a molecular-targeted drug activated by infrared light to the tumor cells and subsequently illuminating the lesion with infrared light. For deep lesions, a needle catheter is used to puncture the tumor, and an illumination fiber (cylindrical diffuser) is inserted into the catheter lumen for internal illumination. However, it can be challenging to place the cylindrical diffusers in an appropriate position as the deep lesions cannot be often confirmed accurately during surgery. We have developed "SlicerPIT", a planning simulation software for photoimmunotherapy. SlicerPIT allows users to place the cylindrical diffuser with its illumination range on preoperative images in 2D and 3D and export the planning data to external image-guided surgical navigation systems. We performed seven cycles of photoimmunotherapy with SlicerPIT in three patients with recurrent head and neck cancer. Preoperative planning for photoimmunotherapy was conducted using SlicerPIT, which could be imported into the navigation system. During the operation, we punctured the needle catheters along with the treatment plan on the navigation screen. Subsequently, intraoperative CT imaging was performed and overlaid with the preoperative treatment plan to confirm the alignment of the cylindrical diffusers as planned, followed by infrared light illumination. Postoperative imaging showed necrosis and shrinkage of the entire tumor in all cycles. SlicerPIT allows for detailed preoperative treatment planning and accurate puncture. It may be a valuable tool to improve the accuracy of photoimmunotherapy for deep lesions and improve patient outcomes.

Comparison of Cervical Pedicle Screw Placement Accuracy With Robotic Guidance System Versus Image Guidance System Using Propensity Score Matching.

A retrospective study. To compare the accuracy of cervical pedicle screw (CPS) placement using a robotic guidance system (RGS) with that of using an image guidance system (IGS; navigation system) through propensity score matching. The RGS may provide accurate CPS placement, which may outperform IGS. However, no study has directly compared the accuracy of CPS placement with the RGS to that with the IGS. We retrospectively reviewed the data of patients who had undergone cervical fusion surgery using CPS with the RGS or IGS. To adjust for potential confounders (patient demographic characteristics, disease etiology, and registration material), propensity score matching was performed, creating robotic guidance (RG) and matched image guidance (IG) groups. The accuracy of CPS placement from C2 to C6, where the vertebral artery runs, was evaluated on postoperative computed tomography images according to the Neo classification (grade 0 to grade 3). Furthermore, the intraoperative CPS revisions and related complications were examined. Using propensity score matching, 22 patients were included in the RG and matched groups each, and a total of 95 and 105 CPSs, respectively, were included in the analysis. In both the axial and sagittal planes, the clinically acceptable rate (grades 0 + 1) of CPS placement did not differ between the RG and matched IG groups (97.9% vs 94.3% and 95.8% vs 96.2%, respectively). The incidence of CPS revision was similar between the groups (2.1% vs 2.9%), and no CPS-related complications were documented. Meanwhile, the incidence of lateral breach (grades 1 + 2 + 3) was significantly lower in the RG group than in the matched IG group (1.1% vs 7.7%, P= 0.037). The RGS and IGS can equally aid in accurate and safe CPS placement in clinical settings. Nonetheless, RGS can further reduce the lateral breach, compared with IGS.

Incremental regression of localization context for automatic segmentation of ossified ligamentum flavum from CT data.

Segmentation of ossified ligamentum flavum (OLF) plays a crucial role in developing computer-assisted, image-guided systems for decompressive thoracic laminectomy. Manual segmentation is time-consuming, tedious, and label-intensive. It also suffers from inter- and intra-observer variability. Automatic segmentation is highly desired. A two-stage, localization context-aware framework is developed for automatic segmentation of ossified ligamentum flavum. In the first stage, localization heatmaps of OLFs are obtained via incremental regression. In the second stage, the obtained heatmaps are then treated as the localization context for a segmentation U-Net. Our framework can directly map a whole volumetic data to its volume-wise labels. We designed and conducted comprehensive experiments on datasets of 100 patients to evaluate the performance of the proposed method. Our method achieved an average Dice similarity coefficient of 61.2±7.6%, an average surface distance of 1.1±0.5mm, and an average positive predictive value of 62.0±12.8%. To the best knowledge of the authors, this is the first study aiming for automatic segmentation of ossified ligamentum flavum. Results from the comprehensive experiments demonstrate the superior performance of the proposed method over the state-of-the-art methods.

Image-guided orbital surgery: a preclinical validation study using a high-resolution physical model

ObjectivePreclinical validation study to assess the feasibility and accuracy of electromagnetic image-guided systems (EM-IGS) in orbital surgery using high-fidelity physical orbital anatomy simulators.MethodsEM-IGS platform, clinical software, navigation instruments and reference...