title: Ultra-High Spatial Resolution, Multi-Energy CT using Photon Counting Detector Technology.
abstract: Two ultra-high-resolution (UHR) imaging modes, each with two energy thresholds, were implemented on a research, whole-body photon-counting-detector (PCD) CT scanner, referred to as sharp and UHR, respectively. The UHR mode has a pixel size of 0.25 mm at iso-center for both energy thresholds, with a collimation of 32 × 0.25 mm. The sharp mode has a 0.25 mm pixel for the low-energy threshold and 0.5 mm for the high-energy threshold, with a collimation of 48 × 0.25 mm. Kidney stones with mixed mineral composition and lung nodules with different shapes were scanned using both modes, and with the standard imaging mode, referred to as macro mode (0.5 mm pixel and 32 × 0.5 mm collimation). Evaluation and comparison of the three modes focused on the ability to accurately delineate anatomic structures using the high-spatial resolution capability and the ability to quantify stone composition using the multi-energy capability. The low-energy threshold images of the sharp and UHR modes showed better shape and texture information due to the achieved higher spatial resolution, although noise was also higher. No noticeable benefit was shown in multi-energy analysis using UHR compared to standard resolution (macro mode) when standard doses were used. This was due to excessive noise in the higher resolution images. However, UHR scans at higher dose showed improvement in multi-energy analysis over macro mode with regular dose. To fully take advantage of the higher spatial resolution in multi-energy analysis, either increased radiation dose, or application of noise reduction techniques, is needed.
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN.
authors.forename: S
authors.initials: S
authors.lastname: Leng
authors.affiliation: CAMP, Technical University of Munich, Garching (Munich), Germany; Siemens Healthcare, Forchheim, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Gutjahr
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN.
authors.forename: A
authors.initials: A
authors.lastname: Ferrero
authors.affiliation: Siemens Healthcare, Forchheim, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Kappler
authors.affiliation: Siemens Healthcare, Forchheim, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Henning
authors.affiliation: Siemens Healthcare, Malvern, PA.
authors.forename: A
authors.initials: A
authors.lastname: Halaweish
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN.
authors.forename: W
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN.
authors.forename: J
authors.initials: J
authors.lastname: Montoya
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN.
authors.forename: C
authors.initials: C
authors.lastname: McCollough
keywords: Computed tomography (CT); dual energy; high resolution; photon counting detector (PCD)