Three-dimensional linear endoscopic ultrasound-feasibility of a novel technique applied for the detection of vessel involvement of pancreatic masses.

Background: Endoscopic ultrasound (EUS) can reliably diagnose and stage pancreatic cancer but is less competent for the differentiation between vascular compression (VC) and invasion (VI).
Aim: Prospective comparison of linear EUS with/without three-dimensional (3D) EUS for vessel involvement in pancreatic cancer to evaluate the feasibility of linear 3D ultrasound.
Material and Methods: Linear echoendoscopy was used to identify the pancreatic tumor, the tumor-vessel relation and for EUS-FNA to obtain tissue diagnosis. Immediately afterwards, 3D image acquisition was performed using a magnetic tracked 3D sensor. The acquisition time was 10-20 s.
Results: EUS results of 22 patients with solid pancreatic lesions were compared to surgical histology. This proved adenocarcinoma in 17 patients and chronic pancreatitis in 5. EUS showed VI in 10 patients, VC in 6, and no vascular involvement (NVI) in 6. Additional 3D evaluation showed VI in 6 patients, VC in 10, and NVI in 6. Surgery proved VI in 7 patients, VC in 9, and NVI in 6. EUS showed VI in 3/5 patients with chronic pancreatitis, 3D showed VC only, while surgery found two patients to have VC and with NVI. In two patients with pancreatic cancer, VI was diagnosed on two dimensional (2D), but VC on 3D evaluation. Surgery showed VC and VI in one each. In the 2D, one patient with NVI had VI on surgery; and on 3D one VC proved to have NVI at surgery. In 1/22 patients the result of 3D was false negative, while 4/22 were false positives and one false negative in conventional EUS.
Conclusion: Linear 3D EUS seems feasible for pancreatic evaluation. In addition, linear EUS enhanced the evaluation of vascular involvement of pancreatic lesions, especially in chronic pancreatitis.