Laparoscopic Ultrasound Imaging Research Articles

LARLUS: laparoscopic augmented reality from laparoscopic ultrasound.

This research endeavors to improve tumor localization in minimally invasive surgeries, a challenging task primarily attributable to the absence of tactile feedback and limited visibility. The conventional solution uses laparoscopic ultrasound (LUS) which has a long learning curve and is operator-dependent. The proposed approach involves augmenting LUS images onto laparoscopic images to improve the surgeon's ability to estimate tumor and internal organ anatomy. This augmentation relies on LUS pose estimation and filtering. Experiments conducted with clinical data exhibit successful outcomes in both the registration and augmentation of LUS images onto laparoscopic images. Additionally, noteworthy results are observed in filtering, leading to reduced flickering in augmentations. The outcomes reveal promising results, suggesting the potential of LUS augmentation in surgical images to assist surgeons and serve as a training tool. We have used the LUS probe's shaft to disambiguate the rotational symmetry. However, in the long run, it would be desirable to find more convenient solutions.

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.

Vessel segmentation for automatic registration of untracked laparoscopic ultrasound to CT of the liver

Purpose:Registration of Laparoscopic Ultrasound (LUS) to a pre-operative scan such as Computed Tomography (CT) using blood vessel information has been proposed as a method to enable image-guidance for laparoscopic liver resection. Currently, there are solutions for this problem that can potentially enable clinical translation by bypassing the need for a manual initialisation and tracking information. However, no reliable framework for the segmentation of vessels in 2D untracked LUS images has been presented.Methods:We propose the use of 2D UNet for the segmentation of liver vessels in 2D LUS images. We integrate these results in a previously developed registration method, and show the feasibility of a fully automatic initialisation to the LUS to CT registration problem without a tracking device.Results:We validate our segmentation using LUS data from 6 patients. We test multiple models by placing patient datasets into different combinations of training, testing and hold-out, and obtain mean Dice scores ranging from 0.543 to 0.706. Using these segmentations, we obtain registration accuracies between 6.3 and 16.6 mm in 50% of cases.Conclusions:We demonstrate the first instance of deep learning (DL) for the segmentation of liver vessels in LUS. Our results show the feasibility of UNet in detecting multiple vessel instances in 2D LUS images, and potentially automating a LUS to CT registration pipeline.

Registration of Untracked 2D Laparoscopic Ultrasound to CT Images of the Liver Using Multi-Labelled Content-Based Image Retrieval.

Laparoscopic Ultrasound (LUS) is recommended as a standard-of-care when performing laparoscopic liver resections as it images sub-surface structures such as tumours and major vessels. Given that LUS probes are difficult to handle and some tumours are iso-echoic, registration of LUS images to a pre-operative CT has been proposed as an image-guidance method. This registration problem is particularly challenging due to the small field of view of LUS, and usually depends on both a manual initialisation and tracking to compose a volume, hindering clinical translation. In this paper, we extend a proposed registration approach using Content-Based Image Retrieval (CBIR), removing the requirement for tracking or manual initialisation. Pre-operatively, a set of possible LUS planes is simulated from CT and a descriptor generated for each image. Then, a Bayesian framework is employed to estimate the most likely sequence of CT simulations that matches a series of LUS images. We extend our CBIR formulation to use multiple labelled objects and constrain the registration by separating liver vessels into portal vein and hepatic vein branches. The value of this new labeled approach is demonstrated in retrospective data from 5 patients. Results show that, by including a series of 5 untracked images in time, a single LUS image can be registered with accuracies ranging from 5.7 to 16.4 mm with a success rate of 78%. Initialisation of the LUS to CT registration with the proposed framework could potentially enable the clinical translation of these image fusion techniques.

Preclinical evaluation of ultrasound-augmented needle navigation for laparoscopic liver ablation.

For laparoscopic ablation to be successful, accurate placement of the needle to the tumor is essential. Laparoscopic ultrasound is an essential tool to guide needle placement, but the ultrasound image is generally presented separately from the laparoscopic image. We aim to evaluate an augmented reality (AR) system which combines laparoscopic ultrasound image, laparoscope video, and the needle trajectory in a unified view. We created a tissue phantom made of gelatin. Artificial tumors represented by plastic spheres were secured in the gelatin at various depths. The top point of the sphere surface was our target, and its 3D coordinates were known. The participants were invited to perform needle placement with and without AR guidance. Once the participant reported that the needle tip had reached the target, the needle tip location was recorded and compared to the ground truth location of the target, and the difference was the target localization error (TLE). The time of the needle placement was also recorded. We further tested the technical feasibility of the AR system in vivo on a 40-kg swine. The AR guidance system was evaluated by two experienced surgeons and two surgical fellows. The users performed needle placement on a total of 26 targets, 13 with AR and 13 without (i.e., the conventional approach). The average TLE for the conventional and the AR approaches was 14.9mm and 11.1mm, respectively. The average needle placement time needed for the conventional and AR approaches was 59.4s and 22.9s, respectively. For the animal study, ultrasound image and needle trajectory were successfully fused with the laparoscopic video in real time and presented on a single screen for the surgeons. By providing projected needle trajectory, we believe our AR system can assist the surgeon with more efficient and precise needle placement.

Surgical treatment of ovarian endometriomas using intraoperative ultrasound

Aim. To improve the results of the surgical treatment of patients with ovarian endometriomas using intraoperative echography.Materials and methods. The results of the surgical treatment of 138 patients with endometrioid ovarian cysts were prospectively and retrospectively analyzed. The main group consisted of 69 patients, who underwent standard ultrasound examination before and after surgery, as well as intraoperative laparoscopic ultrasound imaging. The control group (retrospectively) consisted of 69 patients with endometrioid ovarian cysts, who were not subject to laparoscopic ultrasound examination.Results. The use of intraoperative transvaginal and laparoscopic echography can reduce the time of surgical revision, reduce the number of intra- and postoperative complications, as well as the frequency of relapses in the postoperative period.Conclusion. According to the obtained results, intraoperative ultrasound echography has a high diagnostic accuracy of up to 99.2%. This method of intraoperative diagnosis allows the optimal volume and method of surgical intervention to be determined, and the safety and adequacy of surgical treatment to be ensured, thus maximizing the reproductive function.

Significance of three-dimensional reconstruction as a method of preoperative planning of laparoscopic radiofrequency ablation

To discuss the significance of three-dimensional reconstruction as a method of preoperative planning of laparoscopic radiofrequency ablation(LRFA). Thirty-two cases of LRFA admitted from January 2014 to December 2015 in Department of Hepatobiliary Surgery, Chinese People's Liberation Army General Hospital were analyzed(3D-LRFA group). Three-dimensional(3D) reconstruction were taken as a method of preoperative planning in 3D-LRFA group.Other 64 LRFA cases were paired over the same period without three-dimensional reconstruction before the operation (LRFA group). Hepatobiliary system contrast enhanced CT scan of 3D-RFA patients were taken by multi-slice spiral computed tomography(MSCT), and the DICOM data were processed by IQQA(®)-Liver and IQQA(®)-guide to make 3D reconstruction.Using 3D reconstruction model, diameter and scope of tumor were measured, suitable size (length and radiofrequency length) and number of RFA electrode were chosen, scope and effect of radiofrequency were simulated, reasonable needle track(s) was planed, position and angle of laparoscopic ultrasound (LUS) probe was designed and LUS image was simulated.Data of operation and recovery were collected and analyzed. Data between two sets of measurement data were compared with t test or rank sum test, and count data with χ(2) test or Fisher exact probability test.Tumor recurrence rate was analyzed with the Kaplan-Meier survival curve and Log-rank (Mantel-Cox) test. Compared with LRFA group ((216.8±66.2) minutes, (389.1±183.4) s), 3D-LRFA group ((173.3±59.4) minutes, (242.2±90.8) s) has shorter operation time(t=-3.138, P=0.002) and shorter mean puncture time(t=-2.340, P=0.021). There was no significant difference of blood loss(P=0.170), ablation rate (P=0.871) and incidence of complications(P=1.000). Compared with LRFA group ((6.3±3.9)days, (330±102)U/L, (167±64)ng/L), 3D-LRFA group ((4.3±3.1) days, (285±102) U/L, (139±43) ng/L) had shorter post-operative stay(t=-2.527, P=0.016), less post-operation ALT changes (t=-2.038, P=0.048) and post-operative TNF-α changes(t=-2.233, P=0.027). Disease-free survival between two groups was significantly different (χ(2)=4.049, P=0.046). Disease-free survival of 12 months survival rates were 77.6% and 65.7% in 3D-LRFA group and LRFA group, respectively.The median disease-free survival was 16.0 months in LRFA group and over 24.0 months in 3D-LRFA group. Three-dimensional model of liver reconstruction based on image information is a powerful tool in liver surgery planning.It helps to simulate tumor location and vital tubular structure, make plan for interventional treatment, and therefore mean puncture time and operation time is shortened, influence on liver function is reduced, hospital stay is decreased and DFS is prolonged.

Locally rigid, vessel-based registration for laparoscopic liver surgery.

PurposeLaparoscopic liver resection has significant advantages over open surgery due to less patient trauma and faster recovery times, yet is difficult for most lesions due to the restricted field of view and lack of haptic feedback. Image guidance provides a potential solution but is challenging in a soft deforming organ such as the liver. In this paper, we therefore propose a laparoscopic ultrasound (LUS) image guidance system and study the feasibility of a locally rigid registration for laparoscopic liver surgery.MethodsWe developed a real-time segmentation method to extract vessel centre points from calibrated, freehand, electromagnetically tracked, 2D LUS images. Using landmark-based initial registration and an optional iterative closest point (ICP) point-to-line registration, a vessel centre-line model extracted from preoperative computed tomography (CT) is registered to the ultrasound data during surgery.ResultsUsing the locally rigid ICP method, the RMS residual error when registering to a phantom was 0.7 mm, and the mean target registration error (TRE) for two in vivo porcine studies was 3.58 and 2.99 mm, respectively. Using the locally rigid landmark-based registration method gave a mean TRE of 4.23 mm using vessel centre lines derived from CT scans taken with pneumoperitoneum and 6.57 mm without pneumoperitoneum.ConclusionIn this paper we propose a practical image-guided surgery system based on locally rigid registration of a CT-derived model to vascular structures located with LUS. In a physical phantom and during porcine laparoscopic liver resection, we demonstrate accuracy of target location commensurate with surgical requirements. We conclude that locally rigid registration could be sufficient for practically useful image guidance in the near future.

TU‐C‐144‐01: Image Guidance and Assessment of Therapeutic Ultrasound

Despite significant advances made over the past decade in ultrasound (US) and magnetic resonance imaging (MRI) for guidance and assessment of high intensity focused ultrasound (HIFU) treatments many challenges remain. Recent developments address clinically relevant barriers to image guidance of therapeutic ultrasound. This session will feature invited presentations on (1) the use of MRI temperature mapping in presence of fat, within bone, and moving tissues, (2) dual mode ultrasound array (DMUA) systems for imaging and therapy with the advantage of inherent registration between the image‐guidance and therapeutic coordinate systems, (3) echo decorrelation imaging, providing real‐time feedback about cumulative heat‐induced tissue changes, (4) laparoscopic US imaging and HIFU treatments with special emphasis on the use of US to assess temperature change as well as tissue characteristics; and (5) opportunities for medical physicists to participate in the development, treatment planning, and quality control aspects of image‐guided HIFU therapy.Learning Objectives:1. To understand the role of various MRI and US technologies in guidance and monitoring of HIFU therapy, including MR temperature mapping, dual mode ultrasound array systems, echo decorrelation imaging for ablation assessment, and laparoscopic US‐guided HIFU2. To identify opportunities for medical physicists in assessment and deployment of technologies in image‐guided therapeutic ultrasoundDr. Carol is the Chief Development Officer for US HIFU, LLC

Clinical effects of laparoscopic ultrasound imaging in robot-assisted abdominal surgery

Clinical effects of laparoscopic ultrasound imaging in robot-assisted abdominal surgery

Laparoscopic ultrasound as the primary method for bile duct imaging during cholecystectomy

Intraoperative fluorocholangiography (IOC) has been the standard method for bile duct imaging during cholecystectomy. Laparoscopic ultrasound (LUS) has been evaluated as a possible alternative, but has been used less frequently. The authors examined the evolving use of these two methods to assess the relative utility of LUS as the primary method for routine bile duct imaging during laparoscopic cholecystectomy (LC). This study analyzed a prospective database containing 423 consecutive cholecystectomies performed by one attending surgeon in an academic medical center between 1995 and 2005. Intraoperative bile duct imaging was performed in 371 (94%) of 396 LCs performed for cholelithiasis. As recorded, IOC was performed in 239 cases, LUS in 236 cases, and both in 104 cases. Choledocholithiasis was present in 50 patients (13%). Common bile duct stones (CBDS) were identified by LUS in 3% of the patients without preoperative indicators of CBDS, and in 10% of the patients with one or more indicators. As shown by the findings, LUS had a positive predictive value of 100%, a negative predictive value of 99.6%, a sensitivity of 92.3%, and a specificity of 100% for detecting CBDS. Also, LUS identified clinically significant bile duct anatomy in 6% of the patients. In 1995, LUS was used for 20% of cases, whereas by 2005, it was used for 97% of cases. Conversely, the use of IOC decreased from 93% to 23%. With moderate experience, LUS can become the primary routine imaging method for evaluating the bile duct during LC. It is as reliable as IOC for detecting choledocholithiasis. In addition, LUS can locate the common bile duct during difficult dissections. On the basis of this experience, LUS is used currently in nearly all LCs and is the sole method for bile duct imaging in 75% of these cases. IOC is used as an adjunct to LUS when LUS imaging is inadequate, when stronger clinical indicators of choledocholithiasis are present, or when biliary anatomy remains uncertain.

Diagnostic Laparoscopy and Laparoscopic Ultrasound for Staging of Patients With Malignant Proximal Bile Duct Obstruction

Tumor staging in patients with a malignant obstruction of the proximal bile duct is focused on selecting patients who could benefit from a resection. Diagnostic laparoscopy, which has proved its value in several gastrointestinal malignancies, has been used routinely at our hospital since 1993 in patients with a malignant obstruction of the proximal bile duct, although data in the literature with regard to its additional value are conflicting. Therefore the diagnostic accuracy of diagnostic laparoscopy in patients with malignant proximal bile duct obstruction was evaluated. From January 1993 to May 2000, diagnostic laparoscopy was performed in 110 patients (61 males and 49 females), with a mean age of 60 years (range 30 to 80 years), who had a suspected malignant proximal bile duct tumor and in whom “potential resectability” was demonstrated by means of conventional radiologic staging methods (i.e., ultrasound combined with Doppler imaging, CT, endoscopic retrograde cholangiopancreatography, and percutaneous transhepatic cholangiography). Laparoscopy revealed histologically proved incurable disease in 44 (41%) of the 110 patients (31 with metastases and 13 with extensive tumor ingrowth). Laparoscopic ultrasound imaging, however, revealed histologically proved incurable disease in one patient (1%), thereby preventing exploratory laparotomy in 46 because these patients had already been treated by palliative endoscopic stent placement. The remaining 65 patients were staged as having a resectable tumor and underwent surgical exploration. Thirty patients had an unresectable tumor (distant metastases in five; tumor ingrowth in surrounding tissues in 24) or benign disease (one patient). Sensitivity and negative predictive value of diagnostic laparoscopy for detecting unresectable disease were 60% and 52%, respectively. Diagnostic laparoscopy avoided unnecessary laparotomy in 41% of patients with a malignant proximal bile duct obstruction considered resectable according to conventional imaging studies. The additional value of laparoscopic ultrasound was limited. Therefore diagnostic laparoscopy should be performed routinely in the workup of patients with a potentially resectable proximal bile duct tumor. ( J Gastrointest Surg 2002;6:426–431.)

Evaluation of real-time imaging using a laparoscopic ultrasound probe during operative endoscopic procedures.

To evaluate rigid and flexible ultrasound transducers introduced through a laparoscopic port to image pelvic anatomy during operative endoscopy as a means of mapping the pelvic anatomy, detecting pathology, and for real-time tracking of intra-uterine procedures. Prospective, descriptive, non-comparative. Laparoscopy, hysteroscopy and real-time, gray-scale ultrasonography were performed simultaneously in 36 patients. Laparoscopic ultrasound was performed using 10 mm diameter, 7.5 MHz gray-scale rigid and steerable transducers for imaging of the ovaries and uterus during operative endoscopy (Aloka, Wallingford, CT, USA). All patients underwent intra-operative evaluation using this probe to assess uterine and ovarian structures and to track instruments intra-operatively during complex intra-uterine hysteroscopic procedures and for intra-operative sonohysterography. Laparoscopic ultrasound provided visualization of structures and delineation of ovarian anatomy needle placement for tracking microscissors and intra-operative sonohysterography. The ultrasonography provided information useful for determining the configuration of normal anatomic structures, the localization of and more precise incision placement for anatomic abnormalities and for intra-operative guidance during hysteroscopic resection of intra-uterine adhesions. The imaging also provided details of intra-uterine anatomy through sonohysterography performed during chromotubation. However, no additional information regarding ovarian or uterine abnormalities was noted beyond that detected on pre-operative transvaginal ultrasonography. No technical problems were encountered. No additional operative time was required. Real-time laparoscopic ultrasound imaging is useful in monitoring complex intra-uterine operative procedures and in detailing intra-uterine anatomy during intra-operative sonohysterography. However, it did not provide more enhanced imaging of ovarian anatomy beyond images obtained with pre-operative transvaginal imaging. This imaging technique may have broad application for a variety of endoscopic operative procedures with the potential to impact on operative decision-making and requires further evaluation.

Laparoscopic ultrasound imaging of adrenal tumors during laparoscopic adrenalectomy

Background: The purpose of this study was to determine the usefulness of laparoscopic ultrasound (LUS) during laparoscopic adrenalectomy (LA) and to define the ultrasound imaging characteristics of various adrenal tumors.Methods: LUS was utilized in 27 patients who underwent LA (including one bilateral adrenalectomy) from May 1994 to October 1998. Tumor size ranged from 1.0 to 5.5 cm (mean 3.3 cm), and a transabdominal lateral approach to LA was used.Results: LUS localized the adrenal gland and tumor in all 28 adrenalectomies and demonstrated the relationship of the tumor to the kidney and adjacent vascular structures (renal artery/vein and inferior vena cava). The adrenal vein was visualized sonographically in only six cases (21%). Pheochromocytomas were mild to markedly heterogenous, whereas most aldosteronomas and cortical adenomas were homogenous. LUS provided useful information to the surgeon in 11 of 28 cases (39%) by: 1) localizing the adrenal gland and tumor and/or guiding the dissection; 2) demonstrating that tumors ≥4 cm were confined to the adrenal gland; and 3) investigating suspected pathology in other organs. Mean operating time for LUS was 10.9 min (range 5 to 24 min) and calculated hospital charges were $602.Conclusions: LUS accurately localizes adrenal tumors, helps define their relationship to adjacent structures, and provides confirmation that larger tumors are amenable to laparoscopic resection. LUS is a useful adjunct to laparoscopic adrenalectomy in selected patients.