Feasibility of an Electromagnetic Navigation System in a Standard Clinical Ultrasound Endoscopy Setting

Treatment planning and prognosis of Non-Small-Cell Lung Carcinoma (NSCLC) are
highly dependent on preoperative staging. Endoscopic Ultrasonography guided
Fine Needle Aspiration (EUS-FNA) is the preferred staging method.
However, pulmonary physicians have experienced difficulties getting proficient
in this procedure. This is because the endoscopic image is very poor, which
leads to the Ultrasound (US) image to be the only input for orientation. The
interpretation of these images proves to be difficult.
Using an Electromagnetic Tracking System (EMTS) to track the patient*s and the
endoscope*s position, it is possible to display the endoscope*s position and
orientation relative to the patient in a volumetric anatomical map, based on a
CT scan. This provides the physician with additional information which aids the
(novice) physician in interpreting the US image and which can lead to a
reduction of procedure time.

The goal of this study is to investigate the feasibility of the integration of
an EMTS in a standard clinical EUS setting.

This study is designed as a pilot study.
A 3D anatomical map is produced of patients who are planned for non-emergency
EUS-FNA and who have signed informed consent. This map is based on a (CE-/PET-)
CT scan which is already available, so no additional CT scans are required for
this study.
Prior to the EUS procedure three Electromagnetic (EM) position sensors are
taped to the subject and a custom designed EM sensor tool is introduced in the
working channel of the EUS endoscope. Using an EMTS the position of the
endoscope relative to the patient is continuously calculated and displayed on
an additional screen. By visualizing several anatomical landmarks (lymph nodes)
in the US plane and comparing the position of the US plane to the same
landmarks on the CT data the orthogonal distance can be calculated. This is a
measure for the accuracy of the system. Subsequently the planned FNA is
performed.
Directly afterwards the physician fills out a Standard Usability Survey (SUS).

The risk for adverse events is negligible in this study. As long as the
exclusion criteria are maintained, the addition of the electromagnetic
navigation system to the EUS-FNA procedure does not pose any kind of threat to
the subject.
The burden of this study to the subject consists of a prolongation of procedure
time. Although the introduction of the endoscope in the esophagus can be
experienced as annoying, most patients are not bothered by its presence once it
is inserted. A lengthening of procedure time would thus not result in an
increase of burden to the subject. If for whatever reason the subject does
experience the procedure as very uncomfortable he can indicate this during the
procedure. In consultation with the physician the procedure can then be stopped
or shortened, by directly continuing with the FNA. The physician can also make
this decision independently.