Navigation Improves Tumor Ablation Performance: Results From a Novel Liver Tumor Simulator Study

The applications of augmented reality in image-guided tumor ablations: A scoping review

BACKGROUND

Interventional radiology employs minimally invasive image-guided procedures for diagnosing and treating various conditions. Among these procedures, alcohol and thermal ablation techniques have shown high efficacy. However, these procedures present challenges such as increased procedure time, radiation dose, and risk of tissue injury. This scoping review aims to explore how augmented reality (AR) can mitigate these challenges and improve the accuracy, precision, and efficiency of image-guided tumor ablation while improving patient outcomes.

METHODS

A scoping review of the literature was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guideline to identify published literature investigating AR in image-guided tumor ablations. We conducted our electronic searches using PubMed, Scopus, Web of Sciences and CINAHL from inception to April 27th, 2023. The following Boolean terms were used for the search: ("augmented reality" OR "AR" OR "navigation system" OR "head mounted device" OR "HMD") AND ("tumor ablation" OR "radiofrequency tumor ablation" OR "microwave tumor ablation" OR "cryoablation"). We considered articles eligible for our scoping review if they met the following conditions: (1) published in English only, (2) focused on image-guided tumour ablations, (3) incorporated AR techniques in their methodology, (4) employed an aspect of AR in image-guided tumour ablations, and (5) exclusively involved human subjects. Publications were excluded if there was no mention of applying AR, or if the study investigated interventions other than image-guided tumour ablations.

RESULTS

Our search results yielded 1,676 articles in our initial search of the databases. Of those, 409 studies were removed as duplicates. 1,243 studies were excluded during the title and abstract screening. 24 studies were assessed for eligibility in the full-text stage. 19 studies were excluded, resulting in a final selection of only five studies that satisfied our inclusion criteria. The studies aimed to assess AR's efficacy in tumor ablations. Two studies compared an optical-based AR system with CT guidance. Two studies used a head-mounted AR device, while one used a dual-camera setup. Various tumor types were examined, including bone, abdominal soft tissue, breast, hepatic, renal, colorectal, and lung lesions. All studies showed positive results, including reduced radiation exposure, shorter procedures, and improved navigation, and targeting assistance.

CONCLUSION

AR systems enhance image-guided tumor ablations by improving the accuracy of ablation probe placements and increasing efficiency. They offer real-time guidance, enhanced visualization, and improved navigation, resulting in optimal needle placement. AR reduces radiation exposure and shortens procedure times compared to traditional CT-guided techniques. However, limitations like small sample sizes and technical challenges require further research. Despite this, AR shows potential benefits and larger, diverse studies are needed for validation.

The application of augmented reality for improving clinical skills: a scoping review

Augmented reality technology had developed rapidly in recent years and had been applied in many fields, including medical education. Augmented reality had potential to improve students' knowledge and skills in medical education. This scoping review primarily aims to further elaborate the current studies on the implementation of augmented reality in advancing clinical skills. This study was conducted by utilizing electronic databases such as PubMed, Embase, and Web of Science in June 2022 for articles focusing on the use of augmented reality for improving clinical skills. The Rayyan website was used to screen the articles that met the inclusion criteria, which was the application of augmented reality as a learning method in medical education. Total of 37 articles met the inclusion criteria. These publications suggested that using augmented reality could improve clinical skills. The most researched topics explored were laparoscopic surgery skills and ophthalmology were the most studied topic. The research methods applied in the articles fall into two main categories: randomized control trial (RCT) (29.3%) and non-RCT (70.3%). Augmented reality has the potential to be integrated in medical education, particularly to boost clinical studies. Due to limited databases, however, any further studies on the implementation of augmented reality as a method to enhance skills in medical education need to be conducted.

Smartphone Augmented Reality Outperforms Conventional CT Guidance for Composite Ablation Margins in Phantom Models

PURPOSE

To develop and evaluate a smartphone augmented reality (AR) system for a large 50-mm liver tumor ablation with treatment planning for composite overlapping ablation zones.

MATERIALS AND METHODS

A smartphone AR application was developed to display tumor, probe, projected probe paths, ablated zones, and real-time percentage of the ablated target tumor volume. Fiducial markers were attached to phantoms and an ablation probe hub for tracking. The system was evaluated with tissue-mimicking thermochromic phantoms and gel phantoms. Four interventional radiologists performed 2 trials each of 3 probe insertions per trial using AR guidance versus computed tomography (CT) guidance approaches in 2 gel phantoms. Insertion points and optimal probe paths were predetermined. On Gel Phantom 2, serial ablated zones were saved and continuously displayed after each probe placement/adjustment, enabling feedback and iterative planning. The percentages of tumor ablated for AR guidance versus CT guidance, and with versus without display of recorded ablated zones, were compared among interventional radiologists with pairwise t-tests.

RESULTS

The means of percentages of tumor ablated for CT freehand and AR guidance were 36% ± 7 and 47% ± 4 (P = .004), respectively. The mean composite percentages of tumor ablated for AR guidance were 43% ± 1 (without) and 50% ± 2 (with display of ablation zone) (P = .033). There was no strong correlation between AR-guided percentage of ablation and years of experience (r < 0.5), whereas there was a strong correlation between CT-guided percentage of ablation and years of experience (r > 0.9).

CONCLUSIONS

A smartphone AR guidance system for dynamic iterative large liver tumor ablation was accurate, performed better than conventional CT guidance, especially for less experienced interventional radiologists, and enhanced more standardized performance across experience levels for ablation of a 50-mm tumor.

Integrating Navigation-Assisted Ablation in the Locoregional Treatment of Hepatocellular Carcinoma

Importance

With the increasing prevalence of hepatocellular carcinoma (HCC), ablative therapy is a critical treatment option to achieve a cancer-free state. The anatomic location of the tumor can be a challenge, and select hepatic locations of a tumor require laparoscopic-assisted strategies to safely reach and treat the lesion.

Objective

To assess the association of real-time ultrasonography-augmented navigation for HCC ablation with patient survival, operative time, and rate of incomplete ablations.

Design, Setting, and Participants

This retrospective case-control study was conducted among a prospectively collected database of more than 750 patients with HCC who were treated with ablation therapy with and without the use of navigation at a single quaternary medical center from June 2011 to January 2021. Data were analyzed from October 2022 through June 2023.

Exposure

Real-time ultrasonography-augmented navigation.

Main Outcomes and Measures

The primary outcome was rate of incomplete ablations in patients undergoing HCC ablation with vs without navigation. Secondary outcomes included overall survival (OS), progression-free survival (PFS), and operative time.

Results

The analytic cohort included 467 patients (mean [SD] age, 62.4 [7.8] years; 355 male [76.0%]; 21 Hispanic [4.5%], 67 non-Hispanic Black [14.5%], and 347 Non-Hispanic White [75.0%] among 463 patients with race and ethnicity data). The most common etiology of liver disease was hepatitis C infection (187 patients with etiology data [40.0%]), and 348 of 458 patients with TMN staging data (76.0%) had TNM stage 1 disease. There were 187 individuals treated with navigation and 280 individuals treated without navigation. Patients who underwent navigation-assisted ablation were more likely to have stage 2 disease based on TNM staging (62 of 183 patients [33.9%] vs 47 of 275 patients [17.1%] with TMN data; P < .002) and had a higher mean (SD) number of lesions (1.3 [0.5] vs 1.2 [0.5] lesions; P = .002) and a longer mean (SD) operation time (113.2 [29.4] vs 109.6 [32.3] minutes; P = .04). Patients who underwent navigation were also more likely to have tumors in segment 8 (59 patients [32.1%] vs 53 of 275 patients with segment data [19.3%] with segment data; P = .005) and less likely to have tumors in segment 4 (20 patients [10.9%] vs 54 patients with segment data [19.6%]; P = .005). Overall mean (SD) time to recurrence after treatment was 10.0 (12.5) months, with similar rates for patients with navigation vs no navigation. There were no differences in incomplete ablation rate (10 patients [9.2%] vs 10 patients [10.5%]; P = .32), OS, or PFS between patients undergoing ablation with and without navigation.

Conclusions and Relevance

In this study, use of navigation was associated with comparable outcomes to undergoing ablation without navigation, although patients with navigation had more locally advanced disease. These findings suggest that use of real-time navigation in laparoscopic-assisted ablation of liver cancer should be considered as a useful tool for treating challenging tumors.