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Keywords:
Interventional non-vascular, Lung, Oncology, CT, PET-CT, Image manipulation / Reconstruction, Biopsy, Perception image, Instrumentation, Image registration, Cancer
Authors:
G. Bizzarri, A. Bianchini, D. Valle, L. Di Vito, L. Velari, S. De Nuntis, A. Dell'Era; Albano Laziale/IT
DOI:
10.1594/ecr2017/B-1277
Methods and materials
For the present study a MyLabTwice ultrasound scanner equipped with an EM tracking system and Virtual Navigation (VN) software (ESAOTE,
Italy) and a 64 MDCT (Aquilion,
Toshiba,
Japan) were used.
The procedure was performed with a convex transducer with single use multi-angle (15°-30°-45°) guiding system and reusable tracking bracket for magnetic sensor (CIVCO,
USA) (Fig 1).
Spatial coregistration was obtained with a reference device (omniTRAX) with a dedicated additional magnetic sensor (Fig 2).
In order to evaluate the possible influence of ferromagnetic environment ( CT gantry and table) on the accuracy of the magnetic tracking system,
we performed tests using a homemade phantom consisting of a styrofoam box with some targets inside (Fig 3).
Following this,
we checked the accuracy of the system performing the biopsy in the patient with superficial lesions visible on both CT and US (Fig 4-5) comparing the planned and the actual position of the coaxial needle.
Biopsies were carried out using a coaxial technique with a 17G coaxial needle and a 18G trucut needle.
2-3 samples were obtained from each lesion.
15 patients with mediastinal or pulmonary lesions were enrolled.
The patient was asked to lie down on the CT table in the most suitable decubitus position (supine or prone) with the thorax on the plastic support for the magnetic generator (Fig 6).
The reference tool was attached to the patient’s skin in the appropriate area,
and a preliminary CT scan was performed with a reduced Z-axis,
including the target lesion and the reference tool (omniTRAX) in the FOV.
Images (2-3 mm.
axial scan) were loaded from PACS to the ultrasound scanner and coregistered with the probe position.
VN modality was activated and a virtual scan (virtual ultrasound) was performed moving the probe through the scanned area looking for the target and the best approach (Fig 7).
Once the target lesion was visualized and the approach for biopsy was planned,
local anesthesia was performed.
The coaxial needle was advanced using the probe-guiding system at the estimated depth in a technique similar to US guided biopsies.
A small Z-axis CT scan was made to check the correct position of the coaxial needle,
and then the biopsy was performed (Fig 8).
Finally,
a low-dose whole lung scan was performed in order to rule out any complications.