Intraoperative Ultrasound Imaging Research Articles

Enabling extracorporeal ultrasound imaging with the da Vinci robot for transoral robotic surgery: a feasibility study.

Transoral robotic surgery (TORS) is a challenging procedure due to its small workspace and complex anatomy. Ultrasound (US) image guidance has the potential to improve surgical outcomes, but an appropriate method for US probe manipulation has not been defined. This study evaluates using an additional robotic (4th) arm on the da Vinci Surgical System to perform extracorporeal US scanning for image guidance in TORS. A stereoscopic imaging system and da Vinci-compatible US probe attachment were developed to enable control of the extracorporeal US probe from the surgeon console. The prototype was compared to freehand US by nine operators in three tasks on a healthy volunteer: (1) identification of the common carotid artery, (2) carotid artery scanning, and (3) identification of the submandibular gland. Operator workload and user experience were evaluated using a questionnaire. The robotic US tasks took longer than freehand US tasks (2.09x longer; ) and had higher operator workload (2.12x higher; ). However, operator-rated performance was closer (avg robotic/avg freehand=0.66; ), and scanning performance measured by MRI-US average Hausdorff distance provided no statistically significant difference. Extracorporeal US scanning for intraoperative US image guidance is a convenient approach for providing the surgeon direct control over the US image plane during TORS, with little modification to the existing operating room workflow. Although more time-consuming and higher operator workload, several methods have been identified to address these limitations.

Indocyanine green (ICG)-guided robotic resection for liver adenoma: combined technologies for precision surgery.

HCA resection is crucial to prevent bleeding and malignant transformation. The aim of this study was to enhance the precision of tumor resection in hepatocellular adenoma (HCA) through the combination of intraoperative ultrasound (IOUS) and indocyanine green (ICG) fluorescence imaging. ICG was intravenously injected 24h before surgery, enabling positive staining of HCA nodules. IOUS guided the parenchymal transection performed using the RoboLap approach. IOUS combined with ICG effectively demarcated lesions, allowing precision surgery while sparing healthy liver tissue. Intraoperative frozen examination further validated the potential of ICG to identify previously undetected lesions. The study showed promising advantages of ICG in HCA resections, potentially reducing the risk of recurrence and malignant transformation. The combined robotic and laparoscopic approach improved the feasibility of parenchymal-sparing surgery, offering a cautious assessment of HCA lesions.

Gross pathology of brain mass lesions by intraoperative ultrasonography: a comparative study

BackgroundThe purpose of this study was to evaluate the ability of intraoperative ultrasound (IOUS) to differentiate the gross pathological features of brain mass lesions in comparison with preoperative imaging and confirmable histopathological results.ResultsA total of 365 patients were operated on for brain mass lesions removal from May 2017 to May 2022 under the guidance of intraoperative ultrasound with transducers 2.5–8 megahertz (MHZ). Ultrasound gross pathological findings were compared to the preoperative imaging and the confirmable histopathological results. Intraoperative ultrasound defined either internal or external gross pathological features of all brain mass lesions. The IOUS showed spontaneous enhancements of the brain abscess walls, which were equivalent to contrasted CT and MRI. Significantly large diameters were noted in the IOUS measurement of abscesses in comparison with CT and MRI (P = 0.001). The walls of the brain abscesses were significantly well defined in IOUS imaging in comparison with CT (P = 0.001) and equivalent to MRI. IOUS showed equivalent significance to CT and MRI in characterizing intra-parenchymal hematomas. Significantly large diameters were noted in the IOUS measurement of hematomas in comparison with CT and MRI (P = 0.001). IOUS showed significant definition of brain tumors in comparison with CT and MRI regarding tumor edge definition, tumor contours, necrosis, and cystic components (cystic definition, cystic multiplicity, cystic trabeculations, and cystic wall thickness) (P = 0.001). IOUS was equivalent to CT and MRI regarding intra-tumoral hematomas and brain edema. IOUS was equivalent to CT regarding calcification detection. The significant criteria for high-grade brain tumors versus low grade by IOUS were: P = 0.001 (necrosis, brain edema, rare calcifications, presence of cystic components, thick cystic walls, large diameter, hypo-echogenicity, and heterogeneity); P = 0.002 (cystic trabeculations); P = 0.005 (multiple cysts); and P = 0.03 (irregular contour). IOUS can characterize brain tumors and suspect specific and significant criteria for many types with great overlap.ConclusionsIntraoperative ultrasound has the ability to differentiate the gross pathological features of brain mass lesions in comparison with preoperative imaging and confirmable histopathological results.

Real-time localization for port-implanted catheter tip by echocardiographic guidance

The clinical data of 23 patients undergoing real-time echocardiography-guided infusion port implantation in the Breast Center of Tsinghua Changgung Hospital in Beijing from January to July 2021 were analyzed. The length of catheter insertion L1 was initially estimated using surface measurement method in all patients. Intraoperatively, transthoracic echocardiography was applied using the parasternal four-chamber view to visualize the catheter image within the right atrium, and the length of catheter insertion L2 was recorded under the guidance of echocardiography. Postoperatively, chest radiographs were taken in the upright position to observe the position of the catheter tip. According to chest CT scans, the ideal length (L) for catheter tip placement was calculated when it was located at the junction of superior vena cava and right atrium. Bland-Altman scatter plot analysis and linear regression fitting test were used on L1 and L2 respectively with L to evaluate the consistency. A total of 23 patients were included in this study, among which one case of left breast cancer patient undergoing breast-conserving surgery had difficulty in identifying the catheter tip position due to residual pleural effusion obscuring the imaging of the cardiac apex four-chamber view. In 22 patients, the results of intraoperative ultrasound imaging were good, including 1 case of catheter ectopic to azygos vein, and 21 cases of right atrial catheter could be detected by ultrasound. Statistical analysis showed that there was a good consistency between L1 and L, L2 and L, and the difference between them was d=0.28 cm (95%CI:-1.76-2.31 cm) and d=0.20 cm(95%CI:-0.84-1.23 cm), respectively, with no statistical significance (P>0.05). In the linear regression model, L2 and L had a higher fit than L1, and the difference was statistically significant (R²=0.954, P<0.001). This study found that real-time echocardiographic localization technique can be applied in adult port surgery to replace X-ray-guided real-time catheter tip detection and adjustment to the optimal position.

Cystic Echinococcosis of the Liver: Correlation Between Intra-Operative Ultrasound and Pre-Operative Imaging.

Background: Imaging plays an essential role in the management of hepatic hydatid cysts (HCE). The objective of our study was to determine the correlation between pre-operative ultrasound, computed tomography (CT), and intra-operative ultrasound (IOUS) in studying the characteristics and complications of HCE. Patients and Methods: This was a prospective, descriptive, and analytical study conducted in the General Surgery Department of Habib Bourguiba Hospital in Sfax. The study included patients with HCE who underwent conservative surgery between April 2017 and June 2022. Results: We enrolled 49 patients with 94 cysts. At the end of our study, IOUS allowed for better detection of HCE (98.8%) regardless of the number of cysts per patient. IOUS and CT were accurate in studying the location of cysts (κ = 1), whereas pre-operative abdominal ultrasound was less efficient (κ = 0.870). IOUS was the best examination for detecting exocysts (κ = 0.961), studying daughter cysts (κ = 0.823), and exploring vascular relations, but it was less effective (κ = 0.523) in detecting calcifications. Regarding classifications, ultrasound and CT had similar results. However, IOUS was most reliable in differentiating between CE3b and CE4 types (κ = 0.653). Ultrasound, CT, and IOUS were not sensitive in detecting latent HCE suppurations and cystobiliary fistulas. Conclusions: Performing IOUS is essential to prevent recurrences and reduce post-operative morbidity.

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.

Feasibility of novel intraoperative navigation for anatomical liver resection using real-time virtual sonography combined with indocyanine green fluorescent imaging technology.

To analyze the feasibility and clinical effect of novel intraoperative navigation of real-time virtual sonography (RVS) combined with indocyanine green (ICG) fluorescent imaging technology in anatomical liver resection (ALR) for hepatocellular carcinoma. The clinical data of 41 patients who underwent ALR using RVS intraoperative navigation combined with ICG fluorescent imaging technology in the Department of Hepatobiliary Surgery of Peking University International Hospital from January 2020 to May 2022 were retrospectively analyzed. RVS was applied to guide the surgical plane through fusing real-time intraoperative ultrasound images with corresponding preoperative CT or MRI images. Operation methods, operation time, intraoperative blood loss, operative margin, hospital stay and postoperative complications were analyzed. The 1-year overall survival rate and tumor-free survival rate of patients were followed up by outpatient review or telephone calls. ALR surgery was performed on each of 41 patients. There were no deaths during perioperative period and postoperative complications occurred in 7 cases (17.1%). The postoperative pathological examinations demonstrated all cases of hepatocellular carcinoma and negative operative margins. The 41 patients were followed up for 12 to 20 months, with a median follow-up time of 14 months. The overall survival rate 1 year after surgery was 100.0% (41/41), 3 patients (7.3%) experienced tumor recurrence, and the tumor-free survival rate of 1 year after surgery was 92.7% (38/41). In conclusion, novel intraoperative navigation of RVS combined with ICG fluorescent imaging technology is safe and feasible in anatomical segmental hepatectomy of hepatocellular carcinoma.

Hyperechoic Area Under Insular Gliomas: A Potentially Hazardous Intraoperative Ultrasound Artifact

Intraoperative ultrasound (IOUS) images can be distorted by various artifacts. During surgeries for insular low-grade gliomas (LGGs), we repeatedly observed a distinct hyperechoic artifact adjacent to medial tumor borders, localized in brain regions with normal appearance on magnetic resonance imaging (MRI) that has not been reported before. We retrospectively evaluated saved 3-dimensional (3D) IOUS images of 20 patients harboring insular LGGs. Twelve patients were operated on between 2010 and 2015 using an older navigated 3D IOUS system. Additionally, 3D-IOUS images of 8 patients operated on between 2021 and 2023 using a new high-end 3D-IOUS system were evaluated. The investigated region was the area under medial tumor borders, which were defined using preoperative MRI. In 17 out of 20 cases (85%), a distinct hyperechoic area adjacent to medial tumor borders localized in brain regions with normal appearance on preoperative MRI was found; in the remaining 3 cases the saved images were suboptimal and did not allow evaluation of the area under the medial tumor borders. Although the causes of this bright artifact are unclear, we can hypothesize that the reverberation in between different parallel layers of white and gray matter localized under the insula could play a role in its appearance. Importantly, as this hyperechoic area was depicted already before any tumor resection, it may lead to erroneous conclusion that the tumor spreads more medially. Potential resection in this region may cause significant neurologic sequelae.

Segmentation-based Registration of Pre and Intra-operative Brain Ultrasound Images Using Particle Swarm Optimization

Segmentation-based Registration of Pre and Intra-operative Brain Ultrasound Images Using Particle Swarm Optimization

P07.04.A ELASTIC IMAGE FUSION OF INTRAOPERATIVE ULTRASOUND AND PREOPERATIVE MRI FOR IMPROVING NAVIGATION ACCURACY IN BRAIN TUMOR SURGERY

Abstract BACKGROUND In brain surgery, neuronavigation based on preoperative MRI is limited by various physical and operational factors, such as surgery-induced brain shift. Using navigated intraoperative ultrasound (iUS) imaging and 3D iUS image reconstruction may help improve neuronavigation. However, the registration of MRI and US scans can lead to spatial inconsistencies between the two modalities. This study aims to evaluate the clinical integration of navigated iUS imagining and its potential to improve the accuracy of resection during brain tumor surgery by comparing the performance of rigid and elastic MRI-iUS image fusion algorithms during retrospective evaluation. MATERIAL AND METHODS N = 50 patients with brain tumors were prospectively enrolled in this trial. The neuronavigation system (BrainLab AG) used in the study allowed for the reconstruction and integration of 3D iUS imaging, which was acquired multiple times throughout the surgery using a tracked ultrasound probe (BK Medical). Prototypes of automatic rigid and elastic MRI-iUS image fusion algorithms (Brainlab Elements Image Fusion) were retrospectively applied to improve co-registration accuracy between the MRI and iUS data. To evaluate the image co-registration accuracy, anatomical landmarks were defined in the MRI and iUS scans and used to measure Euclidean distances between each landmark pair. RESULTS Improvements in the image quality over the course of the study indicated that skills in US handling are essential. Contrast behavior and tumor structure influence the visibility of the tumor in the US. Artifacts caused by hemostatic agents challenge the US image quality and the fluid-filled resection cavity requires experience in probe handling. In terms of image fusion, significant mismatches of the iUS and MRI data were reported. For scans acquired before resection, rigid fusion using a novel co-registration algorithm may enhance the registration accuracy with mean target registration errors for two representative patients of 6.5/8.9 mm and 3.7/3.4 mm before and after registration update, respectively. For iUS scans acquired after tumor resection, rigid fusion is inherently limited due to non-linear brain shifts. Therefore, elastic image fusion has been applied to provide deformable MR-iUS image co-registration. CONCLUSION Navigated iUS imaging can be integrated into clinical routine and the use of MR-iUS image co-registration for updating navigation is a promising tool to compensate brainshift during surgical resection. However, further studies are needed to quantify the accuracy and assess whether iUS could potentially replace the use of iMRI in resection control of selected cases.

Ultrasound-Based Registration for the Computer-Assisted Navigated Percutaneous Scaphoid Fixation.

An ultrasound (US)-based computer-assisted approach has the potential to improve the accuracy and precision of screw placement for the percutaneous fixation of scaphoid fractures and also reduce the radiation dose for patient and clinical staff. Therefore, a surgical plan based on preoperative diagnostic computed tomography (CT) is registered with intraoperative US images, enabling a navigated percutaneous fracture fixation. However, approaches published so far rely on semimanual methods for intraoperative registration and are limited by long computation times. To address these challenges, we propose the employment of deep learning-based methods for US segmentation and registration in order to achieve a fast and fully automated yet robust registration process. For validation of the proposed US-based approach, we first provide a comparison of methods for segmentation and registration, assess their contribution to the overall error throughout our pipeline, and, finally, evaluate navigated screw placement in an in vitro study on 3-D printed carpal phantoms. Successful screw placement has been achieved for all ten screws, with deviations from the planned axis of 1.0 ± 0.6 and 0.7 ± 0.3 mm at the distal and proximal pole, respectively. The complete automation and total duration of about 12 s also allow seamless integration of our approach into the surgical workflow.

An innovative approach to assess spinal canal expansion following French-door cervical laminoplasty by intraoperative ultrasonography.

To investigate the feasibility and effectiveness of applying intraoperative ultrasound (IOUS) to evaluate spinal canal expansion in patients undergoing French-door cervical laminoplasty (FDCL). Twenty-five patients who underwent FDCL for multilevel degenerative cervical myelopathy were prospectively recruited. Formulae describing the relationship between laminoplasty opening angle (LOA) and laminoplasty opening size, the increase in sagittal canal diameter and the spinal canal area were deduced with trigonometric functions. The LOA was measured with IOUS imaging during surgery, and other spinal canal parameters were assessed. Actual spinal canal enlargement was verified on postoperative CT images. Linear correlation analysis and Bland‒Altman analysis were used to evaluate correlation and agreement between the intraoperative and postoperative measurements. The LOA at C5 measured with IOUS was 27.54 ± 3.12°, and it was 27.23 ± 3.02° on postoperative CT imaging. Linear correlation analysis revealed a significant correlation between IOUS and postoperative CT measurements (r = 0.88; p < 0.01). Bland-Altman plots showed good agreement between these two methods, with a mean difference of 0.30°. For other spinal canal expansion parameter measurements, correlation analysis showed a moderate to a high degree of correlation (p < 0.01), and Bland-Altman analysis indicated good agreement. In conclusion, during the French-door cervical laminoplasty procedure, application of IOUS can accurately evaluate spinal canal expansion. This innovative method may be helpful in improving surgical accuracy by enabling the operator to measure and determine canal enlargement during surgery, leading to ideal clinical outcomes and fewer postoperative complications. The use of intraoperative ultrasonography to assess spinal canal expansion following French-door cervical laminoplasty may improve outcomes for patients undergoing this procedure by providing more accurate measurements of spinal canal expansion. • Spinal canal expansion after French-door cervical laminoplasty substantially influences operative prognosis; insufficient or excessive lamina opening may result in unexpected outcomes. • Prediction of spinal canal expansion during surgery was previously impracticable, but based on this study, intraoperative ultrasonography offers an innovative approach and strongly agrees with postoperative CT measurement. • Since this is the first research to offer real-time canal expansion guidance for cervical laminoplasty, it may improve the accuracy of the operation and produce ideal clinical outcomes with fewer postoperative complications.

Factors affecting the primary patency of native arteriovenous fistulas after ultrasound-guided percutaneous transluminal angioplasty

Objective By analyzing the clinical history, laboratory test indexes, and intraoperative ultrasound imaging data of patients receiving ultrasound-guided percutaneous transluminal angioplasty (UG-PTA) for the first time, the application value of UG-PTA in the treatment of peripheral stenosis of autogenous arteriovenous fistula (AVF) and the related factors affecting postoperative patency were investigated. Methods A total of 381 patients with dysfunction of radio-cephalic AVF were treated with UG-PTA from June 2017 to September 2019. According to the inclusion and exclusion criteria, 199 patients were included in this study. Baseline characteristics of patients, including demographic, clinical, and laboratory data, were collected. Kaplan–Meier’s survival curve was used to demonstrate the cumulative primary patency rate of UG-PTA. Univariate and multivariate Cox regression analysis was performed on clinical, anatomic, biochemical, and medication variables to identify the predictors of postintervention primary patency. Results The early technical success rate of UG-PTA was 98.4% (375/381). One hundred and ninety-nine patients, with an average age of 52.9 years, were analyzed, 97 of whom were males (48.7%). The median follow-up duration was 21 months. No major complication was observed. Postintervention primary patency rates were 87.7%, 75.8%, and 60.0% at 6, 12, and 24 months, respectively. A previously failed AVF (HR, 1.935, 95% CI 1.071–3.494; p = .029) and an increased level of parathyroid hormone (HR per 100 pg/mL increase, 1.105; 95% CI 1.014–1.203; p = .004) were identified as independent negative predictors of primary patency of UG-PTA. Conclusions UG-PTA is a safe and effective method for the treatment of peripheral stenosis of AVF. Previously failed AVF and elevated parathyroid hormone levels are associated with lower primary patency rate.

Implications of use of different intraoperative ultrasound modalities during glioma surgery – A comparative study of factors affecting outcomes

BackgroundThe main goal of glioma surgery is to remove the maximum amount of tumor without worsening the patient's neurological condition. Intraoperative ultrasound (US) imaging technologies (2D and 3D) are available to assist surgeons, providing real-time updates. Considering additional time, personnel, and cost, we investigate if comparable outcomes can be achieved using basic (2D) and advanced (3D) technology. ObjectiveWe propose predictive models for (i) glioma tumor resectability (ii) surgical outcome, and (iii) a model to predict the outcome of surgery aided with a particular ultrasound and compare outcomes between 2D and 3D US. MethodologyWe used real-world surgery data from a tertiary cancer centre. Three groups of cases were analyzed (2D US used, 3D US used, and no US used during resection). The data analysis uses hypothesis testing, bootstrap sampling, and logistic regression. ResultsThe preoperatively anticipated extent of tumor removal correlated with the postoperative MRI measurement of tumor removal for US-supported surgery (p=0.01) but not for no US-supported surgeries (p = 0.13). A combination of delineation, eloquence, and the multifocal/multicentric nature of the tumor effectively predicted resectability. The eventual outcome of surgery (actual extent of resection achieved) can be predicted by prior treatment status, delineation, eloquence, and satellite nodules. Based on our prediction model (training set of 350 cases and test of 40 cases of US-guided surgeries), we identify some cases where 3D US seems to offer superior EORs. ConclusionThe resectability of glioma tumors is crucial in determining surgical objectives, and the type of ultrasound used as support impacts tumor removal. The findings in this study aid informed decision-making and optimize imaging technology usage, providing a decision flow for selecting ultrasound based on tumor characteristics.

Piezoelectric bimorph-driven ultrasound scanner for high frequency ultrasound imaging

Ultrasound imaging commonly uses mechanical or electronic scanning methods. However, the mechanical scanning systems are bulky and susceptible to electromagnetic interference, while electronic scanning systems are complex and expensive. A more affordable and compact solution for high frequency preclinical and clinical imaging is single-element transducer based ultrasound imaging. This method offers high spatial resolution with low cost and low complexity. In this study, a novel single-element high frequency ultrasound imaging scanner was introduced. The scanner is based on piezoelectric bimorph drive and designed to be low-cost, compact, and handheld. Tungsten wire phantom imaging was performed on a dedicated ultrasound imaging system, and the obtained results were analyzed and compared. The results demonstrate that piezoelectric bimorph drive allows for high frequency imaging with a scanning speed of up to 208 frames per second. The image quality was higher than that of electromagnetic motor drive. The versatility of the ultrasound imaging system makes it suitable for preclinical and clinical applications, including small animal imaging, ophthalmic imaging, skin imaging, and intraoperative ultrasound imaging.

Anatomy preserving GAN for realistic simulation of intraoperative liver ultrasound images

In ultrasound-guided liver surgery, the lack of large-scale intraoperative ultrasound images with important anatomical structures remains an obstacle hindering the successful application of AI to ultrasound guidance. In this case, intraoperative ultrasound (iUS) simulation should be conducted from preoperative magnetic resonance (pMR), which not only helps doctors understand the characteristics of iUS in advance, but also expands the iUS dataset from various imaging positions, thereby promoting the automatic iUS analysis in ultrasound guidance. Herein, a novel anatomy preserving generative adversarial network (ApGAN) framework was proposed to generate simulated intraoperative ultrasound (Sim-iUS) of liver with precise structure information from pMR. Specifically, the low-rank factors based bimodal fusion was first established focusing on the effective information of hepatic parenchyma. Then, a deformation field based correction module was introduced to learn and correct the slight structural distortion from surgical operations. Meanwhile, the multiple loss functions were designed to constrain the simulation of the content, structures, and style. Empirical results of clinical data showed that the proposed ApGAN obtained higher Structural Similarity (SSIM) of 0.74 and Fr´echet Inception Distance (FID) of 35.54 compared to existing methods. Furthermore, the average Hausdorff Distance (HD) error of the liver capsule structure was less than 0.25 mm, and the average relative (Euclidean Distance) ED error for polyps was 0.12 mm, indicating the high-level precision of this ApGAN in simulating the anatomical structures and focal areas.

Ultrafast Doppler Imaging of Brain Arteriovenous Malformation

Ultrafast ultrasound Doppler imaging offers a new and advantageous intraoperative method for brain lesions. Compared to the conventional color Doppler ultrasound system, the ultrafast Doppler allows us to image hemodynamics in small vasculature in an unprecedented high spatio-temporal resolution without using contrast agent. This report presents an intraoperative ultrafast ultrasound Doppler image of a 53-year-old male with a language eloquent area brain arteriovenous malformation (BAVM). The advanced ultrafast Doppler method provides the nidus vasculature hemodynamics with a spatial resolution of 300 μm at thousands of framerates per second. The image also demonstrates that no abnormal vessels infiltrated the eloquent gyrus as the piamatral small vessels outlined the intact boundary. Successful removal of the nidus with full language function preservation highlights the potentials of ultrafast Doppler imaging to improve diagnostic capabilities and surgical outcomes for patients with intracranial lesions.

Multiresolution discrete optimization registration method of ultrasound and magnetic resonance images based on key points

The registration of preoperative magnetic resonance (MR) images and intraoperative ultrasound (US) images is very important in the planning of brain tumor surgery and during surgery. Considering that the two-modality images have different intensity range and resolution, and the US images are degraded by lots of speckle noises, a self-similarity context (SSC) descriptor based on local neighborhood information was adopted to define the similarity measure. The ultrasound images were considered as the reference, the corners were extracted as the key points using three-dimensional differential operators, and the dense displacement sampling discrete optimization algorithm was adopted for registration. The whole registration process was divided into two stages including the affine registration and the elastic registration. In the affine registration stage, the image was decomposed using multi-resolution scheme, and in the elastic registration stage, the displacement vectors of key points were regularized using the minimum convolution and mean field reasoning strategies. The registration experiment was performed on the preoperative MR images and intraoperative US images of 22 patients. The overall error after affine registration was (1.57 ± 0.30) mm, and the average computation time of each pair of images was only 1.36 s; while the overall error after elastic registration was further reduced to (1.40 ± 0.28) mm, and the average registration time was 1.53 s. The experimental results show that the proposed method has prominent registration accuracy and high computational efficiency.

Automated deep neural network-based identification, localization, and tracking of cardiac structures for ultrasound-guided interventional surgery.

The increase in the use of ultrasound-guided interventional therapy for cardiovascular diseases has increased the importance of intraoperative real-time cardiac ultrasound image interpretation. We thus aimed to develop a deep learning-based model to accurately identify, localize, and track the critical cardiac structures and lesions (9 kinds in total) and to validate the algorithm's performance using independent data sets. This diagnostic study developed a deep learning-based model using data collected from Fuwai Hospital between January 2018 and June 2019. The model was validated with independent French and American data sets. In total, 17,114 cardiac structures and lesions were used to develop the algorithm. The model findings were compared with those of 15 specialized physicians in multiple centers. For external validation, 516,805 tags and 27,938 tags were used from 2 different data sets. Regarding structure identification, the area under the receiver operating characteristic curve (AUC) of each structure in the training data set, optimal performance in the test data set, and median AUC of each structure identification were 1 (95% CI: 1-1), 1 (95% CI: 1-1), and 1 (95% CI: 1-1), respectively. Regarding structure localization, the optimal average accuracy was 0.83. As for structure identification, the accuracy of the model significantly outperformed the median performance of the experts (P<0.01). The optimal identification accuracies of the model in 2 independent external data sets were 89.5% and 90%, respectively (P=0.626). The model outperformed most human experts and was comparable to the optimal performance of all human experts in cardiac structure identification and localization, and could be used in the external data sets.

A novel method of ultrasound-guided positive staining using indocyanine green fluorescence in laparoscopic anatomical liver resection of segments VII and VIII.

Recently, in many Asian centers, laparoscopic anatomical liver resection (LALR) using the indocyanine green (ICG) fluorescence imaging technique has been increasingly applied in resecting hepatocellular carcinoma, even in colorectal liver metastases. However, LALR techniques have not been fully standardized, especially in right superior segments. Due to the anatomical position, prevailing positive staining using a PTCD (percutaneous transhepatic cholangial drainage) needle was superior to negative staining in right superior segments hepatectomy, while it was difficult to manipulate. Herein, we design a novel method of ICG-positive staining for LALR of right superior segments. Between April 2021 and October 2022, we retrospectively studied patients in our institute who underwent LALR of right superior segments using a novel method of ICG-positive staining, which comprised a customized puncture needle and an adaptor. Compared to the PTCD needle, the customized needle was not limited by the abdominal wall and could be punctured from the liver dorsal surface, which was more flexible to manipulate. The adapter was attached to the guide hole of the laparoscopic ultrasound (LUS) probe to ensure the precise puncture path of the needle. Guided by preoperative three-dimensional (3D) simulation and intraoperative laparoscopic ultrasound imaging, we punctured the transhepatic needle into the target portal vein through the adaptor and then slowly injected 5-10ml of 0.025 mg/ml ICG solution into the vessel. LALR can be guided by the demarcation line under fluorescence imaging after injection. Demographic, procedural and postoperative data were collected and analyzed. In this study, 21 patients underwent LALR of the right superior segments with ICG fluorescence-positive staining, and the procedures had a success rate of 71.4%. The average staining time was 13.0 ± 6.4min, the operative time was 230.4 ± 71.7min, R0 resection was 100%, the postoperative hospital stay was 7.1 ± 2.4 days, and no severe puncture complications occurred. The novel customized puncture needle approach seems to be feasible and safe for ICG-positive staining in LALR of right superior segments, with a high success rate and a short staining time.