Percutaneous CT-Guided Abdominal and Pelvic Biopsies: Comparison of an Electromagnetic Navigation System and CT Fluoroscopy

Percutaneous image-guided mesenteric biopsy: how we do it in a high-volume training center

Lesions in the mesentery are unique from other potential biopsy targets in the abdomen or pelvis for several reasons. Mesenteric lesions are among the deepest in the abdomen and are often surrounded by or adjacent to small bowel or colon. Mesenteric vasculature is often crowded, and traversing the mesentery often involves crossing multiple vascular planes. Mesenteric lesions and the structures surrounding them within the peritoneal cavity are often highly mobile. All these features can be daunting to any radiologist asked to perform a mesenteric biopsy. We provide a comprehensive overview and guide to percutaneous mesenteric biopsy informed by available literature and experience at two high volume teaching centers. Topics covered include the pitfalls of using prior imaging to determine whether mesenteric biopsy is possible, techniques specific to US or CT-guidance and complications including hemorrhage and bowel injury.

Robot-Assisted CT-Guided Biopsy with an Artificial Intelligence-Based Needle-Path Generator: An Experimental Evaluation Using a Phantom Model

PURPOSE

To investigate the feasibility of a robotic system with artificial intelligence-based lesion detection and path planning for computed tomography (CT)-guided biopsy compared with the conventional freehand technique.

MATERIALS AND METHODS

Eight nodules within an abdominal phantom, incorporating the simulated vertebrae and ribs, were designated as targets. A robotic system was used for lesion detection, trajectory generation, and needle holder positioning. Four interventional radiologists with more than 5 years of experience and 4 with 5 years of experience or less performed 96 robot-assisted insertions encompassing both in-plane and out-of-plane trajectories. Additionally, 32 CT fluoroscopy single-rotation scan-guided freehand needle insertions were performed along the in-plane trajectories. The 3-dimensional (3D), lateral, depth deviations, and insertion time were quantified using post-needle insertion CT scans. Statistical analysis was performed using the unpaired t-test or 1-way analysis of variance, with a significance level of P < .05.

RESULTS

The system detected all target lesions and generated appropriate needle paths. Robot-assisted insertions exhibited significantly smaller 3D and depth deviations than freehand insertions (3.8 mm ± 1.3 vs 4.7 mm ± 1.6, P = .001, and 1.8 mm ± 1.2 vs 2.6 mm ± 1.8, P = .005, respectively). No significant difference was observed in lateral deviations (3.0 mm ± 1.5 vs 3.5 mm ± 1.5, P = .118). Robotic assistance significantly reduced insertion time compared with freehand insertion (17.3 s ± 7.8 vs 78.6 s ± 38.1, P < .001). The same trends were observed between the 2 groups of radiologists.

CONCLUSIONS

The robotic system has the potential to shorten puncture time while maintaining sufficient accuracy in CT-guided procedures.

Remote-Controlled and Teleoperated Systems: Taking Robotic Image Guided Interventions to the Next Stage

Remote-controlled and teleoperated robotic systems mark transformative advancements in interventional radiology (IR), with the potential to enhance precision, reduce radiation exposure, and expand access to care. By integrating robotic devices with imaging guidance, these systems enable precise instrument placement and navigation, thereby improving the efficacy and safety of minimally invasive procedures. Remote-controlled and teleoperated robotic systems-operated by clinicians using control interfaces from within or adjacent to the procedure room-are being adopted for both percutaneous and endovascular interventions. In contrast, although their application is still experimental, teleoperation over long distances hold promise for extending IR services to medically underserved areas by enabling remote procedures. This review details the definitions and components of remote-controlled and teleoperated robotic systems in IR, examines their clinical applications in percutaneous and endovascular interventions, and discusses relevant challenges and future directions for their incorporation into IR practices.

Contribution and advances of robotics in percutaneous oncological interventional radiology

The advent of robotic systems in interventional radiology marks a significant evolution in minimally invasive medical procedures, offering enhanced precision, safety, and efficiency. This review comprehensively analyzes the current state and applications of robotic system usage in interventional radiology, which can be particularly helpful for complex procedures and in challenging anatomical regions. Robotic systems can improve the accuracy of interventions like microwave ablation, radiofrequency ablation, and irreversible electroporation. Indeed, studies have shown a notable decrease of an average 30% in the mean deviation of probes, and a 40% lesser need for adjustments during interventions carried out with robotic assistance. Moreover, this review highlights a 35% reduction in radiation dose and a stable-to-30% reduction in operating time associated with robot-assisted procedures compared to manual methods. Additionally, the potential of robotic systems to standardize procedures and minimize complications is discussed, along with the challenges they pose, such as setup duration, organ movement, and a lack of tactile feedback. Despite these advancements, the field still grapples with a dearth of randomized controlled trials, which underscores the need for more robust evidence to validate the efficacy and safety of robotic system usage in interventional radiology.

Interventional Oncology: 2024 Update

Interventional Oncology (IO) stands at the forefront of transformative cancer care, leveraging advanced imaging technologies and innovative interventions. This narrative review explores recent developments within IO, highlighting its potential impact facilitated by artificial intelligence (AI), personalized medicine and imaging innovations. The integration of AI in IO holds promise for accelerating tumour detection and characterization, guiding treatment strategies and refining predictive models. Imaging modalities, including functional MRI, PET and cone beam CT are reshaping imaging and precision. Navigation, fusion imaging, augmented reality and robotics have the potential to revolutionize procedural guidance and offer unparalleled accuracy. New developments are observed in embolization and ablative therapies. The pivotal role of genomics in treatment planning, targeted therapies and biomarkers for treatment response prediction underscore the personalization of IO. Quality of life assessment, minimizing side effects and long-term survivorship care emphasize patient-centred outcomes after IO treatment. The evolving landscape of IO training programs, simulation technologies and workforce competence ensures the field's adaptability. Despite barriers to adoption, synergy between interventional radiologists' proficiency and technological advancements hold promise in cancer care.

Comparison of a Patient-Mounted Needle-Driving Robotic System versus Single-Rotation CT Fluoroscopy to Perform CT-Guided Percutaneous Lung Biopsies

PURPOSE

To compare the effectiveness of percutaneous lung biopsy using a patient-mounted needle-driving robotic system with that using a manual insertion of needles under computed tomography (CT) fluoroscopy guidance.

MATERIALS AND METHODS

In this institutional review board approved study, the cohort consisted of a series of patients who underwent lung biopsies following the intention-to-treat protocol from September 2022 to September 2023 using robot (n = 15) or manual insertion under single-rotation CT fluoroscopy (n = 66). Patient and procedure characteristics were recorded as well as outcomes.

RESULTS

Although age, body mass index, and skin-to-target distance were not statistically different, target size varied (median, 8 mm [interquartile range, 6.5-9.5 mm] for robot vs 12 mm [8-18 mm] for single-rotation CT fluoroscopy; P = .001). No statistical differences were observed in technical success (86.7% [13/15] vs 89.4% [59/66], P = .673), Grade 3 adverse event (AE) (6.7% [1/15] vs 12.1% [8/66], P = .298), procedural time (28 minutes [22-32 minutes] vs 19 minutes [14.3-30.5 minutes], P = .086), and patient radiation dose (3.9 mSv [3.2-5.6 mSv] vs 4.6 mSv [3.3-7.5 mSv], P = .398). In robot-assisted cases, the median angle out of gantry plane was 10° (6.5°-16°), although it was null (0°-5°) for single-rotation CT fluoroscopy (P = .001).

CONCLUSIONS

Robot-assisted and single-rotation CT fluoroscopy-guided percutaneous lung biopsies were similar in terms of technical success, diagnostic yield, procedural time, AEs, and radiation dose, although robot allowed for out-of-gantry plane navigation along the needle axis.

Technical note: A comparison of physician doses in C-Arm and CT fluoroscopy procedures

PURPOSE

We address the misconception that the typical physician dose is higher for CT fluoroscopy (CTF) procedures compared to C-Arm procedures.

METHODS

We compare physician scatter doses using two methods: a literature review of reported doses and a model based on a modified form of the dose area product (DAP). We define this modified form of DAP, "cumulative absorbed DAP," as the product of the area of the x-ray beam striking the patient, the dose rate per unit area, and the exposure time.

RESULTS

The patient entrance dose rate for C-Arm fluoroscopy (0.2 mGy/s) was found to be 15 times lower than for CT fluoroscopy (3 mGy/s). A typical beam entrance area for C-Arm fluoroscopy reported in the literature was found to be 10.6 × 10.6 cm (112 cm2), whereas for CTF was 0.75 × 32 cm (24 cm2). The absorbed DAP rate for C-Arm fluoroscopy (22 mGy*cm2/s) was found to be 3.3 times lower than for CTF (72 mGy*cm2/s). The mean fluoroscopy time for C-Arm procedures (710 s) was found to be 21 times higher than for CT fluoroscopy procedures (23 s). The cumulative absorbed DAP for C-Arm procedures was found to be 9.4 times higher when compared to CT procedures (1.59 mGy*m2 vs. 0.17 mGy*m2).

CONCLUSIONS

The higher fluoroscopy time in C-Arm procedures leads to a much lower cumulative DAP (i.e., physician scatter dose) in CTF procedures. This result can inform interventional physicians deciding on whether to perform inter-procedural imaging inside the room as opposed to retreating from the room.

Artificial Intelligence-Aided Selection of Needle Pathways: Proof-of-Concept in Percutaneous Lung Biopsies

PURPOSE

To evaluate the concordance between lung biopsy puncture pathways determined by artificial intelligence (AI) and those determined by expert physicians.

MATERIALS AND METHODS

An AI algorithm was created to choose optimal lung biopsy pathways based on segmented thoracic anatomy and emphysema in volumetric lung computed tomography (CT) scans combined with rules derived from the medical literature. The algorithm was validated using pathways generated from CT scans of randomly selected patients (n = 48) who had received percutaneous lung biopsies and had noncontrast CT scans of 1.25-mm thickness available in picture archiving and communication system (PACS) (n = 28, mean age, 68.4 years ± 9.2; 12 women, 16 men). The algorithm generated 5 potential pathways per scan, including the computer-selected best pathway and 4 random pathways (n = 140). Four experienced physicians rated each pathway on a 1-5 scale, where scores of 1-3 were considered safe and 4-5 were considered unsafe. Concordance between computer and physician ratings was assessed using Cohen's κ.

RESULTS

The algorithm ratings were statistically equivalent to the physician ratings (safe vs unsafe: κ¯=0.73; ordinal scale: κ¯=0.62). The computer and physician ratings were identical in 57.9% (81/140) of cases and differed by a median of 0 points. All least-cost "best" pathways generated by the algorithm were considered safe by both computer and physicians (28/28) and were judged by physicians to be ideal or near ideal.

CONCLUSIONS

AI-generated lung biopsy puncture paths were concordant with expert physician reviewers and considered safe. A prospective comparison between computer- and physician-selected puncture paths appears indicated in addition to expansion to other anatomic locations and procedures.

CT Navigation for Percutaneous Needle Placement: How I Do It

CT navigation (CTN) has recently been developed to combine many of the advantages of conventional CT and CT-fluoroscopic guidance for needle placement. CTN systems display real-time needle position superimposed on a CT dataset. This is accomplished by placing electromagnetic (EM) or optical transmitters/sensors on the patient and needle, combined with fiducials placed within the scan field to superimpose a known needle location onto a CT dataset. Advantages of CTN include real-time needle tracking using a contemporaneous CT dataset with the patient in the treatment position, reduced radiation to the physician, facilitation of procedures outside the gantry plane, fewer helical scans during needle placement, and needle guidance based on diagnostic-quality CT datasets. Limitations include the display of a virtual (vs actual) needle position, which can be inaccurate if the needle bends, the fiducial moves, or patient movement occurs between scans, and limitations in anatomical regions with a high degree of motion such as the lung bases. This review summarizes recently introduced CTN technologies in comparison to historical methods of CT needle guidance. A "How I do it" section follows, which describes how CT navigation has been integrated into the study center for both routine and challenging procedures, and includes step-by-step explanations, technical tips, and pitfalls.

Cyberknife Radiosurgery for Prostate Cancer after Abdominoperineal Resection (CYRANO): The Combined Computer Tomography and Electromagnetic Navigation Guided Transperineal Fiducial Markers Implantation Technique

In this technical development report, we present the strategic placement of fiducial markers within the prostate under the guidance of computed tomography (CT) and electromagnetic navigation (EMN) for the delivery of ultra-hypofractionated cyberknife (CK) therapy in a patient with localized prostate cancer (PCa) who had previously undergone chemo-radiotherapy for rectal cancer and subsequent abdominoperineal resection due to local recurrence. The patient was positioned in a prone position with a pillow under the pelvis to facilitate access, and an electromagnetic fiducial marker was placed on the patient's skin to establish a stable position. CT scans were performed to plan the procedure, mark virtual points, and simulate the needle trajectory using the navigation system. Local anesthesia was administered, and a 21G needle was used to place the fiducial markers according to the navigation system information. A confirmatory CT scan was obtained to ensure proper positioning. The implantation procedure was safe, without any acute side effects such as pain, hematuria, dysuria, or hematospermia. Our report highlights the ability to use EMN systems to virtually navigate within a pre-acquired imaging dataset in the interventional room, allowing for non-conventional approaches and potentially revolutionizing fiducial marker positioning, offering new perspectives for PCa treatment in selected cases.