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1.
Cardiovasc Diabetol ; 23(1): 196, 2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38849833

ABSTRACT

BACKGROUND: Monocytes play a central role in the pathophysiology of cardiovascular complications in type 2 diabetes (T2D) patients through different mechanisms. We investigated diabetes-induced changes in lncRNA genes from T2D patients with cardiovascular disease (CVD), long-duration diabetes, and poor glycemic control. METHODS: We performed paired-end RNA sequencing of monocytes from 37 non-diabetes controls and 120 patients with T2D, of whom 86 had either macro or microvascular disease or both. Monocytes were sorted from peripheral blood using flow cytometry; their RNA was purified and sequenced. Alignments and gene counts were obtained with STAR to reference GRCh38 using Gencode (v41) annotations followed by batch correction with CombatSeq. Differential expression analysis was performed with EdgeR and pathway analysis with IPA software focusing on differentially expressed genes (DEGs) with a p-value < 0.05. Additionally, differential co-expression analysis was done with csdR to identify lncRNAs highly associated with diabetes-related expression networks with network centrality scores computed with Igraph and network visualization with Cytoscape. RESULTS: Comparing T2D vs. non-T2D, we found two significantly upregulated lncRNAs (ENSG00000287255, FDR = 0.017 and ENSG00000289424, FDR = 0.048) and one significantly downregulated lncRNA (ENSG00000276603, FDR = 0.017). Pathway analysis on DEGs revealed networks affecting cellular movement, growth, and development. Co-expression analysis revealed ENSG00000225822 (UBXN7-AS1) as the highest-scoring diabetes network-associated lncRNA. Analysis within T2D patients and CVD revealed one lncRNA upregulated in monocytes from patients with microvascular disease without clinically documented macrovascular disease. (ENSG00000261654, FDR = 0.046). Pathway analysis revealed DEGs involved in networks affecting metabolic and cardiovascular pathologies. Co-expression analysis identified lncRNAs strongly associated with diabetes networks, including ENSG0000028654, ENSG00000261326 (LINC01355), ENSG00000260135 (MMP2-AS1), ENSG00000262097, and ENSG00000241560 (ZBTB20-AS1) when we combined the results from all patients with CVD. Similarly, we identified from co-expression analysis of diabetes patients with a duration ≥ 10 years vs. <10 years two lncRNAs: ENSG00000269019 (HOMER3-AS10) and ENSG00000212719 (LINC02693). The comparison of patients with good vs. poor glycemic control also identified two lncRNAs: ENSG00000245164 (LINC00861) and ENSG00000286313. CONCLUSION: We identified dysregulated diabetes-related genes and pathways in monocytes of diabetes patients with cardiovascular complications, including lncRNA genes of unknown function strongly associated with networks of known diabetes genes.


Subject(s)
Cardiovascular Diseases , Diabetes Mellitus, Type 2 , Gene Expression Profiling , Gene Expression Regulation , Gene Regulatory Networks , Monocytes , RNA, Long Noncoding , Humans , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/diagnosis , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/complications , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , RNA, Long Noncoding/blood , Monocytes/metabolism , Male , Middle Aged , Female , Cardiovascular Diseases/genetics , Cardiovascular Diseases/diagnosis , Case-Control Studies , Aged , Signal Transduction , Transcriptome , RNA-Seq , Blood Glucose/metabolism
2.
Cancer Med ; 12(13): 14225-14251, 2023 07.
Article in English | MEDLINE | ID: mdl-37191030

ABSTRACT

BACKGROUND: Percutaneous thermal ablation has become the preferred therapeutic treatment option for liver cancers that cannot be resected. Since ablative zone tissue changes over time, it becomes challenging to determine therapy effectiveness over an extended period. Thus, an immediate post-procedural evaluation of the ablation zone is crucial, as it could influence the need for a second-look treatment or follow-up plan. Assessing treatment response immediately after ablation is essential to attain favorable outcomes. This study examines the efficacy of image fusion strategies immediately post-ablation in liver neoplasms to determine therapeutic response. METHODOLOGY: A comprehensive systematic search using PRISMA methodology was conducted using EMBASE, MEDLINE (via PUBMED), and Cochrane Library Central Registry electronic databases to identify articles that assessed the immediate post-ablation response in malignant hepatic tumors with fusion imaging (FI) systems. The data were retrieved on relevant clinical characteristics, including population demographics, pre-intervention clinical history, lesion characteristics, and intervention type. For the outcome metrics, variables such as average fusion time, intervention metrics, technical success rate, ablative safety margin, supplementary ablation rate, technical efficacy rate, LTP rates, and reported complications were extracted. RESULTS: Twenty-two studies were included for review after fulfilling the study eligibility criteria. FI's immediate technical success rate ranged from 81.3% to 100% in 17/22 studies. In 16/22 studies, the ablative safety margin was assessed immediately after ablation. Supplementary ablation was performed in 9 studies following immediate evaluation by FI. In 15/22 studies, the technical effectiveness rates during the first follow-up varied from 89.3% to 100%. CONCLUSION: Based on the studies included, we found that FI can accurately determine the immediate therapeutic response in liver cancer ablation image fusion and could be a feasible intraprocedural tool for determining short-term post-ablation outcomes in unresectable liver neoplasms. There are some technical challenges that limit the widespread adoption of FI techniques. Large-scale randomized trials are warranted to improve on existing protocols. Future research should emphasize improving FI's technological capabilities and clinical applicability to a broader range of tumor types and ablation procedures.


Subject(s)
Ablation Techniques , Carcinoma, Hepatocellular , Catheter Ablation , Liver Neoplasms , Humans , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/surgery , Liver Neoplasms/pathology , Carcinoma, Hepatocellular/surgery , Ablation Techniques/adverse effects , Ablation Techniques/methods , Tomography, X-Ray Computed/methods , Catheter Ablation/adverse effects , Catheter Ablation/methods
4.
Sci Rep ; 12(1): 14153, 2022 08 19.
Article in English | MEDLINE | ID: mdl-35986015

ABSTRACT

Segmentation of abdominal Computed Tomography (CT) scan is essential for analyzing, diagnosing, and treating visceral organ diseases (e.g., hepatocellular carcinoma). This paper proposes a novel neural network (Res-PAC-UNet) that employs a fixed-width residual UNet backbone and Pyramid Atrous Convolutions, providing a low disk utilization method for precise liver CT segmentation. The proposed network is trained on medical segmentation decathlon dataset using a modified surface loss function. Additionally, we evaluate its quantitative and qualitative performance; the Res16-PAC-UNet achieves a Dice coefficient of 0.950 ± 0.019 with less than half a million parameters. Alternatively, the Res32-PAC-UNet obtains a Dice coefficient of 0.958 ± 0.015 with an acceptable parameter count of approximately 1.2 million.


Subject(s)
Image Processing, Computer-Assisted , Liver Neoplasms , Humans , Image Processing, Computer-Assisted/methods , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/pathology , Neural Networks, Computer , Tomography, X-Ray Computed/methods
6.
BMC Med Imaging ; 22(1): 97, 2022 05 24.
Article in English | MEDLINE | ID: mdl-35610600

ABSTRACT

Clinical imaging (e.g., magnetic resonance imaging and computed tomography) is a crucial adjunct for clinicians, aiding in the diagnosis of diseases and planning of appropriate interventions. This is especially true in malignant conditions such as hepatocellular carcinoma (HCC), where image segmentation (such as accurate delineation of liver and tumor) is the preliminary step taken by the clinicians to optimize diagnosis, staging, and treatment planning and intervention (e.g., transplantation, surgical resection, radiotherapy, PVE, embolization, etc). Thus, segmentation methods could potentially impact the diagnosis and treatment outcomes. This paper comprehensively reviews the literature (during the year 2012-2021) for relevant segmentation methods and proposes a broad categorization based on their clinical utility (i.e., surgical and radiological interventions) in HCC. The categorization is based on the parameters such as precision, accuracy, and automation.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Carcinoma, Hepatocellular/diagnostic imaging , Carcinoma, Hepatocellular/surgery , Humans , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/surgery , Magnetic Resonance Imaging , Tomography, X-Ray Computed
7.
Int J Med Robot ; 18(5): e2414, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35486635

ABSTRACT

BACKGROUND: Recent tele-mentoring technologies for minimally invasive surgery (MIS) augments the operative field with movements of virtual surgical instruments as visual cues. The objective of this work is to assess different user-interfaces that effectively transfer mentor's hand gestures to the movements of virtual surgical instruments. METHODS: A user study was conducted to assess three different user-interface devices (Oculus-Rift, SpaceMouse, Touch Haptic device) under various scenarios. The devices were integrated with a MIS tele-mentoring framework for control of both manual and robotic virtual surgical instruments. RESULTS: The user study revealed that Oculus Rift is preferred during robotic scenarios, whereas the touch haptic device is more suitable during manual scenarios for tele-mentoring. CONCLUSION: A user-interface device in the form of a stylus controlled by fingers for pointing in 3D space is more suitable for manual MIS, whereas a user-interface that can be moved and oriented easily in 3D space by wrist motion is more suitable for robotic MIS.


Subject(s)
Robotic Surgical Procedures , Robotics , Humans , Minimally Invasive Surgical Procedures , Surgical Instruments , User-Computer Interface
8.
Int J Surg Protoc ; 25(1): 209-215, 2021.
Article in English | MEDLINE | ID: mdl-34611571

ABSTRACT

INTRODUCTION: Percutaneous thermal ablation is widely adopted as a curative treatment approach for unresectable liver neoplasms. Accurate immediate assessment of therapeutic response post-ablation is critical to achieve favourable outcomes. The conventional technique of side-by-side comparison of pre- and post-ablation scans is challenging and hence there is a need for improved methods, which will accurately evaluate the immediate post-therapeutic response. OBJECTIVES AND SIGNIFICANCE: This review summarizes the findings of studies investigating the feasibility and efficacy of the fusion imaging systems in the immediate post-operative assessment of the therapeutic response to thermal ablation in liver neoplasms. The findings could potentially empower the clinicians with updated knowledge of the state-of-the-art in the assessment of treatment response for unresectable liver neoplasms. METHODS AND ANALYSIS: A rapid review will be performed on publicly available major electronic databases to identify articles reporting the feasibility and efficacy of the fusion imaging systems in the immediate assessment of the therapeutic response to thermal ablation in liver neoplasms. The risk of bias and quality of articles will be assessed using the Cochrane risk of bias tool 2.0 and Newcastle Ottawa tool. ETHICS AND DISSEMINATION: Being a review, we do not anticipate the need for any approval from the Institutional Review Board. The outcomes of this study will be published in a peer-reviewed journal. HIGHLIGHTS: Evaluation of the therapeutic response in liver neoplasms immediately post-ablation is critical to achieve favourable patient outcomes. We will examine the feasibility and technical efficacy of different fusion imaging systems in assessing the immediate treatment response post-ablation. The findings are expected to guide the clinicians with updated knowledge on the state-of-the-art when assessing the immediate treatment response for unresectable liver neoplasms.

9.
ACS Chem Neurosci ; 12(11): 1835-1853, 2021 06 02.
Article in English | MEDLINE | ID: mdl-34008957

ABSTRACT

The blood-brain barrier (BBB) is a prime focus for clinicians to maintain the homeostatic function in health and deliver the theranostics in brain cancer and number of neurological diseases. The structural hierarchy and in situ biochemical signaling of BBB neurovascular unit have been primary targets to recapitulate into the in vitro modules. The microengineered perfusion systems and development in 3D cellular and organoid culture have given a major thrust to BBB research for neuropharmacology. In this review, we focus on revisiting the nanoparticles based bimolecular engineering to enable them to maneuver, control, target, and deliver the theranostic payloads across cellular BBB as nanorobots or nanobots. Subsequently we provide a brief outline of specific case studies addressing the payload delivery in brain tumor and neurological disorders (e.g., Alzheimer's disease, Parkinson's disease, multiple sclerosis, etc.). In addition, we also address the opportunities and challenges across the nanorobots' development and design. Finally, we address how computationally powered machine learning (ML) tools and artificial intelligence (AI) can be partnered with robotics to predict and design the next generation nanorobots to interact and deliver across the BBB without causing damage, toxicity, or malfunctions. The content of this review could be references to multidisciplinary science to clinicians, roboticists, chemists, and bioengineers involved in cutting-edge pharmaceutical design and BBB research.


Subject(s)
Alzheimer Disease , Nanoparticles , Artificial Intelligence , Biological Transport , Blood-Brain Barrier , Drug Delivery Systems , Humans
10.
Int J Comput Assist Radiol Surg ; 15(4): 629-639, 2020 Apr.
Article in English | MEDLINE | ID: mdl-32130645

ABSTRACT

PURPOSE: Cerebral aneurysms are one of the prevalent cerebrovascular disorders in adults worldwide and caused by a weakness in the brain artery. The most impressive treatment for a brain aneurysm is interventional radiology treatment, which is extremely dependent on the skill level of the radiologist. Hence, accurate detection and effective therapy for cerebral aneurysms still remain important clinical challenges. In this work, we have introduced a pipeline for cerebral blood flow simulation and real-time visualization incorporating all aspects from medical image acquisition to real-time visualization and steering. METHODS: We have developed and employed an improved version of HemeLB as the main computational core of the pipeline. HemeLB is a massive parallel lattice-Boltzmann fluid solver optimized for sparse and complex geometries. The visualization component of this pipeline is based on the ray marching method implemented on CUDA capable GPU cores. RESULTS: The proposed visualization engine is evaluated comprehensively and the reported results demonstrate that it achieves significantly higher scalability and sites updates per second, indicating higher update rate of geometry sites' values, in comparison with the original HemeLB. This proposed engine is more than two times faster and capable of 3D visualization of the results by processing more than 30 frames per second. CONCLUSION: A reliable modeling and visualizing environment for measuring and displaying blood flow patterns in vivo, which can provide insight into the hemodynamic characteristics of cerebral aneurysms, is presented in this work. This pipeline increases the speed of visualization and maximizes the performance of the processing units to do the tasks by breaking them into smaller tasks and working with GPU to render the images. Hence, the proposed pipeline can be applied as part of clinical routines to provide the clinicians with the real-time cerebral blood flow-related information.


Subject(s)
Cerebrovascular Circulation/physiology , Imaging, Three-Dimensional/methods , Intracranial Aneurysm/diagnostic imaging , Computer Simulation , Hemodynamics/physiology , Humans , Intracranial Aneurysm/physiopathology , Models, Neurological
11.
Int J Comput Assist Radiol Surg ; 14(12): 2165-2176, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31309385

ABSTRACT

BACKGROUND AND OBJECTIVES: Surgical procedures such as laparoscopic and robotic surgeries are popular since they are invasive in nature and use miniaturized surgical instruments for small incisions. Tracking of the instruments (graspers, needle drivers) and field of view from the stereoscopic camera during surgery could further help the surgeons to remain focussed and reduce the probability of committing any mistakes. Tracking is usually preferred in computerized video surveillance, traffic monitoring, military surveillance system, and vehicle navigation. Despite the numerous efforts over the last few years, object tracking still remains an open research problem, mainly due to motion blur, image noise, lack of image texture, and occlusion. Most of the existing object tracking methods are time-consuming and less accurate when the input video contains high volume of information and more number of instruments. METHODS: This paper presents a variational framework to track the motion of moving objects in surgery videos. The key contributions are as follows: (1) A denoising method using stochastic resonance in maximal overlap discrete wavelet transform is proposed and (2) a robust energy functional based on Bhattacharyya coefficient to match the target region in the first frame of the input sequence with the subsequent frames using a similarity metric is developed. A modified affine transformation-based registration is used to estimate the motion of the features following an active contour-based segmentation method to converge the contour resulted from the registration process. RESULTS AND CONCLUSION: The proposed method has been implemented on publicly available databases; the results are found satisfactory. Overlap index (OI) is used to evaluate the tracking performance, and the maximum OI is found to be 76% and 88% on private data and public data sequences.


Subject(s)
Cardiac Surgical Procedures/methods , Intracranial Aneurysm/surgery , Surgery, Computer-Assisted/methods , Algorithms , Humans , Motion
12.
J Digit Imaging ; 32(3): 420-432, 2019 06.
Article in English | MEDLINE | ID: mdl-30483988

ABSTRACT

This work presents a platform that integrates a customized MRI data acquisition scheme with reconstruction and three-dimensional (3D) visualization modules along with a module for controlling an MRI-compatible robotic device to facilitate the performance of robot-assisted, MRI-guided interventional procedures. Using dynamically-acquired MRI data, the computational framework of the platform generates and updates a 3D model representing the area of the procedure (AoP). To image structures of interest in the AoP that do not reside inside the same or parallel slices, the MRI acquisition scheme was modified to collect a multi-slice set of intraoblique to each other slices; which are termed composing slices. Moreover, this approach interleaves the collection of the composing slices so the same k-space segments of all slices are collected during similar time instances. This time matching of the k-space segments results in spatial matching of the imaged objects in the individual composing slices. The composing slices were used to generate and update the 3D model of the AoP. The MRI acquisition scheme was evaluated with computer simulations and experimental studies. Computer simulations demonstrated that k-space segmentation and time-matched interleaved acquisition of these segments provide spatial matching of the structures imaged with composing slices. Experimental studies used the platform to image the maneuvering of an MRI-compatible manipulator that carried tubing filled with MRI contrast agent. In vivo experimental studies to image the abdomen and contrast enhanced heart on free-breathing subjects without cardiac triggering demonstrated spatial matching of imaged anatomies in the composing planes. The described interventional MRI framework could assist in performing real-time MRI-guided interventions.


Subject(s)
Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional , Magnetic Resonance Imaging, Interventional , Robotics/instrumentation , Abdomen/diagnostic imaging , Computer Simulation , Contrast Media , Humans
13.
Int J Med Robot ; 13(3)2017 Sep.
Article in English | MEDLINE | ID: mdl-27758024

ABSTRACT

BACKGROUND: Open posterior spinal procedures involve extensive soft tissue disruption, increased hospital length of stay, and disfiguring scars. Our aim was to demonstrate the feasibility of using robotic-assistance for minimally invasive exposure of the posterolateral spine with and without carbon dioxide (CO2 ) insufflation. METHODS: Sheep specimens underwent minimally invasive subperiosteal dissection of the spine during three trials. The da Vinci S Surgical system was used for access with and without working space support via CO2 insufflation. RESULTS: Without insufflation, a sub-paraspinal muscle tunnel measuring 16 cm was developed between two 5 cm incisions. With insufflation, the one-sided tunnel length was 12.5 cm but without the soft tissue trauma and obstructed visualization experienced without CO2 . CONCLUSIONS: The use of robot-assistance for minimally invasive access to the posterior spine appears to be feasible. The use of CO2 insufflation greatly improved our ability to visualize and access the posterior vertebral elements.


Subject(s)
Robotic Surgical Procedures/methods , Spine/surgery , Animals , Carbon Dioxide , Humans , Insufflation , Minimally Invasive Surgical Procedures/methods , Models, Anatomic , Models, Animal , Paraspinal Muscles/surgery , Proof of Concept Study , Sheep, Domestic
14.
IEEE Trans Med Imaging ; 35(7): 1686-95, 2016 07.
Article in English | MEDLINE | ID: mdl-26863651

ABSTRACT

Reconstruction of the anterior cruciate ligament (ACL) through arthroscopy is one of the most common procedures in orthopaedics. It requires accurate alignment and drilling of the tibial and femoral tunnels through which the ligament graft is attached. Although commercial computer-assisted navigation systems exist to guide the placement of these tunnels, most of them are limited to a fixed pose without due consideration of dynamic factors involved in different knee flexion angles. This paper presents a new model for intraoperative guidance of arthroscopic ACL reconstruction with reduced error particularly in the ligament attachment area. The method uses 3D preoperative data at different flexion angles to build a subject-specific statistical model of knee pose. To circumvent the problem of limited training samples and ensure physically meaningful pose instantiation, homogeneous transformations between different poses and local-deformation finite element modelling are used to enlarge the training set. Subsequently, an anatomical geodesic flexion analysis is performed to extract the subject-specific flexion characteristics. The advantages of the method were also tested by detailed comparison to standard Principal Component Analysis (PCA), nonlinear PCA without training set enlargement, and other state-of-the-art articulated joint modelling methods. The method yielded sub-millimetre accuracy, demonstrating its potential clinical value.


Subject(s)
Knee Joint , Magnetic Resonance Imaging , Anterior Cruciate Ligament , Anterior Cruciate Ligament Reconstruction , Humans , Tibia
15.
Int J Comput Assist Radiol Surg ; 11(8): 1409-18, 2016 Aug.
Article in English | MEDLINE | ID: mdl-26872810

ABSTRACT

PURPOSE: Despite great advances in medical image segmentation, the accurate and automatic segmentation of endoscopic scenes remains a challenging problem. Two important aspects have to be considered in segmenting an endoscopic scene: (1) noise and clutter due to light reflection and smoke from cutting tissue, and (2) structure occlusion (e.g. vessels occluded by fat, or endophytic tumours occluded by healthy kidney tissue). METHODS: In this paper, we propose a variational technique to augment a surgeon's endoscopic view by segmenting visible as well as occluded structures in the intraoperative endoscopic view. Our method estimates the 3D pose and deformation of anatomical structures segmented from 3D preoperative data in order to align to and segment corresponding structures in 2D intraoperative endoscopic views. Our preoperative to intraoperative alignment is driven by, first, spatio-temporal, signal processing based vessel pulsation cues and, second, machine learning based analysis of colour and textural visual cues. To our knowledge, this is the first work that utilizes vascular pulsation cues for guiding preoperative to intraoperative registration. In addition, we incorporate a tissue-specific (i.e. heterogeneous) physically based deformation model into our framework to cope with the non-rigid deformation of structures that occurs during the intervention. RESULTS: We validated the utility of our technique on fifteen challenging clinical cases with 45 % improvements in accuracy compared to the state-of-the-art method. CONCLUSIONS: A new technique for localizing both visible and occluded structures in an endoscopic view was proposed and tested. This method leverages both preoperative data, as a source of patient-specific prior knowledge, as well as vasculature pulsation and endoscopic visual cues in order to accurately segment the highly noisy and cluttered environment of an endoscopic video. Our results on in vivo clinical cases of partial nephrectomy illustrate the potential of the proposed framework for augmented reality applications in minimally invasive surgeries.


Subject(s)
Endoscopy/methods , Imaging, Three-Dimensional/methods , Color , Humans , Nephrectomy/methods
16.
Surg Endosc ; 30(6): 2641-8, 2016 06.
Article in English | MEDLINE | ID: mdl-26679175

ABSTRACT

BACKGROUND: The aim of this study was to enhance the visual feedback of surgeons, during robotic surgeries, by designing and developing an actuated 2D imaging probe, which is used in conjunction with the traditional stereoscopic camera of the da Vinci surgical system. The probe provides the surgeon with additional visual cues, overcoming visualization constraints encountered during certain scenarios of robot-assisted minimally invasive surgery. METHODS: The actuated imaging probe is implemented as a master-slave tele-manipulated system, and it is designed to be compatible with the da Vinci surgical system. The detachable probe design enables it to be mounted on any of the EndoWrist(®) instruments of the robot and is controlled by the surgeon using a custom-made pedal system. The image from the 2D probe is rendered along with the stereoscopic view on the surgeon's console. RESULTS: The experimental results demonstrate the effectiveness of the proposed actuated imaging probe when used as an additional visualization channel and in surgical scenarios presenting visual problems due to tissue occlusion. CONCLUSION: The study shows the potential benefits of an additional actuated imaging probe when used in conjunction with traditional surgical instruments to perform surgical tasks requiring visualization from multiple orientations and workspaces.


Subject(s)
Feedback , Robotic Surgical Procedures/instrumentation , Surgery, Computer-Assisted/instrumentation , Depth Perception , Equipment Design , Humans , Learning Curve
17.
IEEE Trans Med Imaging ; 35(1): 1-12, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26151933

ABSTRACT

In image-guided robotic surgery, segmenting the endoscopic video stream into meaningful parts provides important contextual information that surgeons can exploit to enhance their perception of the surgical scene. This information provides surgeons with real-time decision-making guidance before initiating critical tasks such as tissue cutting. Segmenting endoscopic video is a challenging problem due to a variety of complications including significant noise attributed to bleeding and smoke from cutting, poor appearance contrast between different tissue types, occluding surgical tools, and limited visibility of the objects' geometries on the projected camera views. In this paper, we propose a multi-modal approach to segmentation where preoperative 3D computed tomography scans and intraoperative stereo-endoscopic video data are jointly analyzed. The idea is to segment multiple poorly visible structures in the stereo/multichannel endoscopic videos by fusing reliable prior knowledge captured from the preoperative 3D scans. More specifically, we estimate and track the pose of the preoperative models in 3D and consider the models' non-rigid deformations to match with corresponding visual cues in multi-channel endoscopic video and segment the objects of interest. Further, contrary to most augmented reality frameworks in endoscopic surgery that assume known camera parameters, an assumption that is often violated during surgery due to non-optimal camera calibration and changes in camera focus/zoom, our method embeds these parameters into the optimization hence correcting the calibration parameters within the segmentation process. We evaluate our technique on synthetic data, ex vivo lamb kidney datasets, and in vivo clinical partial nephrectomy surgery with results demonstrating high accuracy and robustness.


Subject(s)
Imaging, Three-Dimensional/methods , Robotic Surgical Procedures/methods , Algorithms , Animals , Humans , Kidney/pathology , Kidney/surgery , Kidney Neoplasms/pathology , Kidney Neoplasms/surgery , Nephrectomy , Sheep
18.
J Med Imaging (Bellingham) ; 2(2): 024006, 2015 Apr.
Article in English | MEDLINE | ID: mdl-26158101

ABSTRACT

Liver segmentation continues to remain a major challenge, largely due to its intense complexity with surrounding anatomical structures (stomach, kidney, and heart), high noise level and lack of contrast in pathological computed tomography (CT) data. We present an approach to reconstructing the liver surface in low contrast CT. The main contributions are: (1) a stochastic resonance-based methodology in discrete cosine transform domain is developed to enhance the contrast of pathological liver images, (2) a new formulation is proposed to prevent the object boundary, resulting from the cellular automata method, from leaking into the surrounding areas of similar intensity, and (3) a level-set method is suggested to generate intermediate segmentation contours from two segmented slices distantly located in a subject sequence. We have tested the algorithm on real datasets obtained from two sources, Hamad General Hospital and medical image computing and computer-assisted interventions grand challenge workshop. Various parameters in the algorithm, such as [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], play imperative roles, thus their values are precisely selected. Both qualitative and quantitative evaluation performed on liver data show promising segmentation accuracy when compared with ground truth data reflecting the potential of the proposed method.

19.
Med Image Anal ; 25(1): 103-10, 2015 Oct.
Article in English | MEDLINE | ID: mdl-25977157

ABSTRACT

Hilar dissection is an important and delicate stage in partial nephrectomy, during which surgeons remove connective tissue surrounding renal vasculature. Serious complications arise when the occluded blood vessels, concealed by fat, are missed in the endoscopic view and as a result are not appropriately clamped. Such complications may include catastrophic blood loss from internal bleeding and associated occlusion of the surgical view during the excision of the cancerous mass (due to heavy bleeding), both of which may compromise the visibility of surgical margins or even result in a conversion from a minimally invasive to an open intervention. To aid in vessel discovery, we propose a novel automatic method to segment occluded vasculature from labeling minute pulsatile motion that is otherwise imperceptible with the naked eye. Our segmentation technique extracts subtle tissue motions using a technique adapted from phase-based video magnification, in which we measure motion from periodic changes in local phase information albeit for labeling rather than magnification. Based on measuring local phase through spatial decomposition of each frame of the endoscopic video using complex wavelet pairs, our approach assigns segmentation labels by detecting regions exhibiting temporal local phase changes matching the heart rate. We demonstrate how our technique is a practical solution for time-critical surgical applications by presenting quantitative and qualitative performance evaluations of our vessel detection algorithms with a retrospective study of fifteen clinical robot-assisted partial nephrectomies.


Subject(s)
Endoscopy/methods , Kidney Neoplasms/surgery , Kidney/blood supply , Nephrectomy/methods , Renal Artery Obstruction/pathology , Renal Artery Obstruction/surgery , Robotic Surgical Procedures/methods , Surgery, Computer-Assisted/methods , Humans , Imaging, Three-Dimensional , Kidney/surgery , Pattern Recognition, Automated/methods , Reproducibility of Results , Sensitivity and Specificity , Video Recording
20.
Med Image Comput Comput Assist Interv ; 17(Pt 2): 324-31, 2014.
Article in English | MEDLINE | ID: mdl-25485395

ABSTRACT

Synergistic fusion of pre-operative (pre-op) and intraoperative (intra-op) imaging data provides surgeons with invaluable insightful information that can improve their decision-making during minimally invasive robotic surgery. In this paper, we propose an efficient technique to segment multiple objects in intra-op multi-view endoscopic videos based on priors captured from pre-op data. Our approach leverages information from 3D pre-op data into the analysis of visual cues in the 2D intra-op data by formulating the problem as one of finding the 3D pose and non-rigid deformations of tissue models driven by features from 2D images. We present a closed-form solution for our formulation and demonstrate how it allows for the inclusion of laparoscopic camera motion model. Our efficient method runs in real-time on a single core CPU making it practical even for robotic surgery systems with limited computational resources. We validate the utility of our technique on ex vivo data as well as in vivo clinical data from laparoscopic partial nephrectomy surgery and demonstrate its robustness in segmenting stereo endoscopic videos.


Subject(s)
Capsule Endoscopy/methods , Imaging, Three-Dimensional/methods , Kidney Neoplasms/pathology , Kidney Neoplasms/surgery , Nephrectomy/methods , Pattern Recognition, Automated/methods , Surgery, Computer-Assisted/methods , Animals , Image Interpretation, Computer-Assisted/methods , Preoperative Care/methods , Reproducibility of Results , Sensitivity and Specificity , Sheep , Subtraction Technique , Viscera/pathology , Viscera/surgery
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