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Session: Advances in Photon-Counting Imaging [Return to Session]

Reduction of Device Induced Artifacts in Novel Bioresorbable Flow Diverters Using Ultra High Resolution Photon Counting Detector CT

E Koons*, A Oliver, D Kallmes, C McCollough, S Leng, Mayo Clinic, Rochester, MN


WE-G-201-6 (Wednesday, 7/13/2022) 2:45 PM - 3:45 PM [Eastern Time (GMT-4)]

Room 201

Purpose: Device-induced artifacts impose a major challenge in CT imaging to evaluate intracranial aneurysms treated with flow diverting devices. This work assesses artifact reduction of two novel experimental Bioresorbable flow diverters (BRFDs) compared to one clinical device imaged with ultra-high-resolution (UHR) mode on a photon-counting-detector (PCD) CT system.

Methods: Two BRFDs primarily composed of braided proprietary bioresorbable iron or magnesium alloys and one clinical device were placed in silicone tubes with 21mg/cc iodine solution mimicking contrast-enhanced vessels. They were placed in a phantom and scanned with a UHR head protocol (120x0.2mm collimation, 120kV, 230 CARE keV IQ level). Images were reconstructed at a slice thickness of 0.6mm and a sharp kernel of Hr56 (resolution of 12 lp/cm). Image artifacts were evaluated both qualitatively and quantitatively. Lumen areas affected by the device were identified by drawing radial line profiles over 4 angles and averaged over 3 slices. Reduction of CT number in the affected area and its width were quantified.

Results: BRFD presented with reduced streaking, blooming, and beam hardening artifacts relative to the clinical device upon visual inspection. The averages (and standard error) CT number reduction around the device were 131 ± 19, 35 ± 6, and 372 ± 25 HU for the iron, magnesium and clinical FD respectively. The width of the affected area (with artifacts) was 0.56 ± 0.04, 0.4 ± 0.06, and 0.6 ± 0.02 mm, for iron, magnesium, and clinical FDs, respectively. Average CT number for the metal peak was 1708 ± 106, 1345 ±130, and 3169 ± 138 HU, respectively.

Conclusion: The artifacts on PCD UHR images are reduced in BRFDs compared to clinical FD due to decreased concentration of high attenuating metal wires. This artifact reduction potentially allows for improved visualization of neighboring anatomy and pathology relevant for treatment of aneurysms and follow up.

Funding Support, Disclosures, and Conflict of Interest: This study was supported by the National Institutes of Health under award numbers R01 EB028590 and supported in kind by Siemens Healthineers GmbH, who own the evaluated system under the terms of a sponsored research agreement with the Mayo Clinic.


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