Image overlay for CT-guided needle insertions.
OBJECTIVE
We present a 2D image overlay device to assist needle placement on computed tomography (CT) scanners.


METHODS
The system consists of a flat display and a semitransparent mirror mounted on the gantry. When the physician looks at the patient through the mirror, the CT image appears to be floating inside the body with correct size and position as if the physician had 2D 'X-ray vision'. The physician draws the optimal path on the CT image. The composite image is rendered on the display and thus reflected in the mirror. The reflected image is used to guide the physician in the procedure. In this article, we describe the design and various embodiments of the 2D image overlay system, followed by the results of phantom and cadaver experiments in multiple clinical applications.


RESULTS
Multiple skeletal targets were successfully accessed with one insertion attempt. Generally, successful access was recorded on liver targets when a clear path opened, but the number of attempts and accuracy showed variability because of occasional lack of access. Soft tissue deformation further reduced the accuracy and consistency in comparison to skeletal targets.


CONCLUSIONS
The system demonstrated strong potential for reducing faulty needle insertion attempts, thereby reducing X-ray dose and patient discomfort.
Fichtinger
Gabor
G
Johns Hopkins University, Baltimore, MD 21218-2682, USA. gabor@cs.jhu.edu
Deguet
Anton
A
Fischer
Gregory
G
Iordachita
Iulian
I
Balogh
Emese
E
Masamune
Ken
K
Taylor
Russell H
RH
Fayad
Laura M
LM
de Oliveira
Michelle
M
Zinreich
S James
SJ
D000818:Animals; D001707:Biopsy, Needle; D002102:Cadaver; D002138:Calibration; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted; D019047:Phantoms, Imaging; D015641:Radiography, Interventional / Q000295:instrumentation*; D013552:Swine; D014057:Tomography, X-Ray Computed; D014584:User-Computer Interface