Evaluation of intracranial aneurysm coil embolization in phantoms and patients using a high resolution microangiographic fluoroscope (MAF)

Abstract

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.

Synthesis and Characterization of Radiopaque Shape Memory Polymers

“…Samples were imaged in comparison to an industry accepted control Guglielmi detachable coil (GDC10) [6]. Samples were adhered to a polypropylene sheet and imaged through a 0.5" aluminum plate as an analog for human skull x-ray attenuation [7].…”

Intrinsic and total system performance evaluation for a newly developed Solid State X-ray Image Intensifier (SSXII) detector

“…Higher resolution and lower noise detectors for real time x-ray imaging are essential for endovascular image guided interventions (EIGIs) for accurate guidance of devices through the vascular system 7 . Detectors with such capabilities improve the effectiveness of minimally invasive interventional procedures while minimizing radiation dose to patients 8–10 . Our group has developed a new high resolution, high sensitivity region-of-interest (ROI) Solid State X-ray Image Intensifier (SSXII) from the component level which can provide real-time, high spatial-resolution, and low noise (hence, high dynamic range) images even at low exposures because of the high variable on-chip gain of the electron-multiplying CCD (EMCCD) 11 .…”