A novel fusion imaging system for endoscopic ultrasound

Abstract

Background and Objective:Navigation of a flexible endoscopic ultrasound (EUS) probe inside the gastrointestinal (GI) tract is problematic due to the small window size and complex anatomy. The goal of the present study was to test the feasibility of a novel fusion imaging (FI) system which uses electromagnetic (EM) sensors to co-register the live EUS images with the pre-procedure computed tomography (CT) data with a novel navigation algorithm and catheter.Methods:An experienced gastroenterologist and a novice EUS operator tested the FI system on a GI tract bench top model. Also, the experienced gastroenterologist performed a case series of 20 patients during routine EUS examinations.Results:On the bench top model, the experienced and novice doctors reached the targets in 67 ± 18 s and 150 ± 24 s with a registration error of 6 ± 3 mm and 11 ± 4 mm, respectively. In the case series, the total procedure time was 24.6 ± 6.6 min, while the time to reach the clinical target was 8.7 ± 4.2 min.Conclusions:The FI system is feasible for clinical use, and can reduce the learning curve for EUS procedures and improve navigation and targeting in difficult anatomic locations.

Endoscopic ultrasonography and small‐bowel endoscopy: Present and future

“…These techniques have a promising future, especially in patients with difficult anatomy (e.g. anorectal fistulae, rectal cancers) …”

“…anorectal fistulae, rectal cancers). 6,7 INTERVENTIONAL EUS: NEW TOOLS, NEW (AND OLD) APPLICATIONS Endoscopic ultrasonography-guided biopsy A CCEPTED INDICATIONS FOR EUS biopsy are mediastinal lymphadenopathies; 27 intramural or extraparietal gastrointestinal masses (97% sensitivity, 100% specificity); 28 malignant tumors of the biliary tract or gallbladder (87-80% sensitivity, 100% specificity); 29 and upper-GI subepithelial mesenchymal lesions (sensitivity 83%, specificity 73%). [30][31][32] Pancreatic focal lesions still represent the main indication with 80-94% sensitivity and up to 100% specificity.…”

The role of contrast-enhanced endoscopic ultrasound in pancreatic adenocarcinoma

“…[27] Progress in tridimensional ultrasound could enhance staging of pancreatic cancer [Figure 1d],[28] especially in the setting of real-time four-dimensional technologies and/or fusion imaging with PET-CT/MR. [2930]…”

Determination of optimal ultrasound planes for the initialisation of image registration during endoscopic ultrasound-guided procedures

“…During an EUS-guided procedure, an endoscope equipped with an ultrasound (US) transducer and a video camera is inserted and navigated through the gastrointestinal (GI) tract to the stomach and duodenum from which the neighbouring organs such as the pancreas, liver, and biliary ducts can be imaged. However, the small field-of-view, the variability in pancreatobiliary anatomy and the lack of easily definable landmarks make this procedure technically difficult to perform and require skill in both endoscopy and US image interpretation [ 3 ].…”

“…Multimodal registration of intra-procedure US with pre-procedure images, such as computed tomography (CT) or magnetic resonance (MR) scans, can improve the navigation to specific locations during image-guided procedures by providing additional anatomical context [ 4 , 5 ]. Initialising the MR/CT to US image registration, for example, by identifying MR- or CT- visible anatomical landmarks on electromagnetically tracked EUS planes [ 3 , 5 – 7 ], is critical for robust and accurate registration. However, the relationship between the initialisation-plane selection and registration robustness and accuracy is complex and frequently unintuitive due to: (a) the loss of 3D context in 2D EUS; (b) the limited number of correspondent EUS/CT-visible anatomical point landmarks available with which a registration can be performed; and (c) the high dependency on operator skill and experience [ 8 ].…”