Article Figures & Data
Figures
- Fig 1.
Components of the stereotactic CT navigator.
A, View of the upper portion of the device, seen from above (operator’s perspective). The V pattern is at a 53° angle. The measured millimeter distance between the two V limbs (slice-select) is printed on a scale (left), and a 5-mm scaled pattern grid is seen parallel to the section plane location (Slice Selection mm Scale). A linear transparent millimeter scale and needle support offset scale are actuated by the remote control cable. A millimeter scale on the moving needle guide is used to define the offset. Two small needle supports can be used to hold the needle at a precise point. The upper V pattern is supported on an elevated circular clear plastic support ring.
B, View of the upper level device V pattern. The remote control cable, clear base support, and upper offset scale control component are labeled.
C, View of the device from above (operator’s view), with the skin entry point localizer seen beneath the upper remote control offset scale component.
D, View of a nonsterile opaque skin entry point locator pattern.
- Fig 2.
CT scans of a navigator-directed brain biopsy.
A, Two-millimeter-thick CT section centered at the target section plane location. The ideal chosen targeting vector is drawn on the computer monitor. In this case, the procedural goal was to direct the needle to the lateral superior margin of the lateral ventricle (not shown). The two small hyperattenuated dots shown on the scalp are the V pattern limbs of the skin entry point localizer. The millimeter distance measured on the image between these two points (black dotted arrow) is used to define the slice-select location. The measured distance from the zero reference pattern limb dot to the vector drawn on the image (white dotted arrow) is the offset distance.
B, Device upper level V pattern in place. The small mini-burr hole has already been drilled and is centered on the planned vector skin entry point. The two limbs of the skin entry point pattern are labeled. The moveable upper level device offset scale has small dots for direct millimeter visualization. In this case, the measured distance between the two V limbs is 60 mm because the distance between the two V limbs is six dots (10 mm/dot) on the upper scale. The chosen targeting vector is drawn on the image, and the offset is 17 mm; the needle is supported at this position.
C, Needle placed on the surface of the brain. This offset accurately aligns the needle with the chosen vector. The needle is advanced the measured depth distance.
D, Needle in the target point, precisely along the planned vector (see A).
- Fig 3.
Photograph of the actual needle biopsy setup shows the needle entering the scalp at the previously determined and marked skin entry point. It is seen supported through the upper level needle guide, held along the upper offset scale at the correct location, to assure proper vector alignment. The remote control cable can be used to precisely position the needle in the image section plane along the chosen targeting vector.
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