Image Registered Gastroscopic Ultrasound (IRGUS) in human subjects: a pilot study to assess feasibility

Abstract

Background and study aims EUS is a complex procedure due to subtleties of ultrasound interpretation, the small field of observation, and the uncertainty of probe position and orientation. Animal studies demonstrated that Image Registered Gastroscopic Ultrasound (IRGUS) is feasible and may be superior to conventional EUS in efficiency and image interpretation. This study explores whether these attributes of IRGUS will be evident in human subjects with an aim of assessing the feasibility, effectiveness, and efficiency of IRGUS in patients with suspected pancreatic lesions. Patients and methods Prospective feasibility study at a tertiary care academic medical center in human patients withpancreatic lesions on CT scan who were scheduled to undergo conventional EUS were randomly chosen to undergo their procedure with IRGUS. Main outcome measures include feasibility, ease of use, systemfunction, validated task load (TLX) assessment instrument and IRGUS experience questionnaire. Results Five subjects underwent IRGUS without complication. Localization of pancreatic lesions was accomplished efficiently and accurately (TLX temporal demand 3.7%; TLX effort 8.6%). Image synchronization and registration was accomplished in real-time without procedure delay. Mean assessment score for endoscopist experience with IRGUS was positive (66.6±29.4). Real-time display of CT images in the EUS plane and echoendoscope orientation were the most beneficial characteristic. Conclusions IRGUS appears feasible and safe in human subjects, and efficient and accurate at identification of probe position and image interpretation. IRGUS has the potential to broaden adoption of EUS techniques and shorten EUS learning curves. Clinical studies comparing IRGUS to conventional EUS are ongoing.

Real-time computed tomography-based augmented reality for natural orifice transluminal endoscopic surgery navigation

“…Further miniaturization of the system could also render it applicable to intravascular and other minimally invasive procedures such as intrahepatic tumour chemoembolization. In its current form the system has already been used successfully in endoscopic procedures in humans, specifically in association with EUS for localizing pancreatic lesions 10 .…”

Endoscopic ultrasonography and small‐bowel endoscopy: Present and future

“…1,2 Various applications have been developed to improve diagnosis, staging of oncological diseases and lesion targeting during interventional procedures. [3][4][5] These techniques have a promising future, especially in patients with difficult anatomy (e.g. anorectal fistulae, rectal cancers).…”

“…Fusion imaging represents a combination of ultrasound with computed tomography (CT)/magnetic resonance (MR), based on electromagnetic positioning and tracking of the ultrasound transducer and co‐registration with the corresponding CT/MR image . Various applications have been developed to improve diagnosis, staging of oncological diseases and lesion targeting during interventional procedures . These techniques have a promising future, especially in patients with difficult anatomy (e.g.…”

Beyond conventional endoscopic ultrasound

“…The hybrid CT-EUS procedure was recently tested in five human patients, showing accurate identification of probe position and easier image interpretation, with better localization of pancreatic lesions and possible shortening of the learning curve [41 ]. Furthermore, based on the EUS system capabilities, CE-PD-EUS or low mechanical index harmonic CE-EUS can be visualized simultaneously with dynamic spiral CT data, allowing an estimation of angiogenesis inside the tumors through different imaging modalities [42 ].…”