Program Information
Reduction of Blooming Effects in High Resolution Imaging of Arterial Walls Using Photon-Counting CT
K Rajendran*, S Leng , S Jorgensen , E Ritman , C McCollough , Mayo Clinic, Rochester, MN
Presentations
WE-DE-605-9 (Wednesday, August 2, 2017) 10:15 AM - 12:15 PM Room: 605
Purpose: To reduce blooming effects in contrast-enhanced arterial wall imaging using high resolution photon-counting CT (PCCT).
Methods: Ultra-high resolution (UHR) PCCT scans of a 3D-printed carotid phantom and a porcine model of enhanced vasa vasorum were performed. The carotid phantom with 20mg/mL iodine contrast in lumen was scanned at 120kV with thresholds [25,52] keV in UHR (0.25mm pixel-size at isocenter) and macro (0.5mm pixel-size at isocenter) modes. The animal scan was performed in UHR mode at 140kV, with thresholds [30,70] keV at multiple time points following iodinated contrast injection. The left carotid (LC) featured surgically-enhanced VV density and the right carotid (RC) served as the control. PCCT images were reconstructed using weighted-filtered back projection with a quantitative, medium sharp kernel (D50). CT image deconvolution was also applied to the UHR-PCCT images incorporating the system point-spread function. Mean CT number from annular ROIs was measured at multiple radial distances in the phantom wall to quantify bloom-induced CT number contamination. Similarly, mean CT numbers were obtained using annular ROIs in the wall region of carotids in the [30-140]keV images from the animal scan.
Results: The mean wall CT numbers in the carotid phantom images showed lesser blooming in UHR mode compared to macro mode. Blooming was further reduced post deconvolution (CT number consistency was achieved at radial distances >0.5mm from lumen boundary). The mean wall CT numbers from the animal scan showed maximum CT number enhancement in the LC at 12s post injection due to the increased VV density.
Conclusion: Improved CT number accuracy and detection of increased vasa vasorum in artery wall due to reduced blooming effects were demonstrated in a phantom study and an animal study using UHR-PCCT respectively. Image deconvolution further reduces the bloom-induced discrepancies. This enables reliable measurements of artery wall perfusion which is a precursor of atherosclerosis.
Funding Support, Disclosures, and Conflict of Interest: The project described was supported by Grant number(s) EB016966 and C06-RR018898 from the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
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