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Intracranial aneurysm (IA) embolization using Gugliemi Detachable Coils (GDC) under x-ray fluoroscopic guidance is
one of the most important neuro-vascular interventions. Coil deposition accuracy is key and could benefit substantially
from higher resolution imagers such as the micro-angiographic fluoroscope (MAF). The effect of MAF guidance
improvement over the use of standard Flat Panels (FP) is challenging to assess for such a complex procedure. We
propose and investigate a new metric, inter-frame cross-correlation sensitivity (CCS), to compare detector performance
for such procedures. Pixel (P) and histogram (H) CCS's were calculated as one minus the cross-correlation coefficients
between pixel values and histograms for the region of interest at successive procedure steps. IA treatment using GDC's
was simulated using an anthropomorphic head phantom which includes an aneurysm. GDC's were deposited in steps of
3 cm and the procedure was imaged with a FP and the MAF. To measure sensitivity to detect progress of the procedure
by change in images of successive steps, an ROI was selected over the aneurysm location and pixel-value and histogram
changes were calculated after each step. For the FP, after 4 steps, the H and P CCSs between successive steps were
practically zero, indicating that there were no significant changes in the observed images. For the MAF, H and P CCSs
were greater than zero even after 10 steps (30 cm GDC), indicating observable changes. Further, the proposed
quantification method was applied for evaluation of seven patients imaged using the MAF, yielding similar results (H
and P CCSs greater than zero after the last GDC deposition). The proposed metric indicates that the MAF can offer
better guidance during such procedures.
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