This pilot study wants to determine to which extent SPCCT allows obtaining images with improved quality and diagnostic confidence when compared to standard Dual Energy CT (DECT), both with and without contrast agent injection. Depending on the anatomical structures/organs to be visualized during CT examinations, different scanning protocols are performed with quite variable ionizing radiation doses. Therefore, in order to obtain the most extensive and representative results of the improvement in image quality between SPCCT and DECT that will be performed CT imaging on several body regions and structures, including diabetic foot, diabetic calcium coronary scoring, adrenal glands, coronary arteries, lung parenchyma, kidney stones, inner ear, brain and joints, earl/temporal bone, colorectal carcinosis.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
339
For the dual-layer spectral CT scanner (IQon®, Philips, Amsterdam, The Netherlands), the following parameters will be used for the acquisition: * Tube potential 120 kVp; * Tube current time product of 150 mAs; * Gantry revolution time 0.33 s; * Automatic exposure control (angular and longitudinal) combined xyz-axis; * Beam collimation geometry 64 x 0.625 mm - scan field-of-view - 22 cm;
The SPCCT scanner is a prototype spectral photon-counting computed tomography system derived from a modified clinical CT system with a field-of-view (FOV) of 168 mm in-plane, and a z-coverage of 20 mm. It is equipped with energy-sensitive photon-counting detectors relying on the direct conversion high band gap semiconductor of cadmium zinc telluride (CZT). The electronics comprises 5 rate counters with 5 different configurable energy thresholds. The SPCCT scanner has the following parameters: * Base platform : iCT scanner * Tube Voltage (kVp) : 120, capability for imaging at 80 and 100 kVp * Tube current (mA) : 10 - 300 * Spatial Resolution : \> 30 lp/cm, ≤ 250 µm * Z-coverage isocenter (mm) : 20 mm * FOV (mm) : 500 * Minimum rotation time : 0.33 s/rotation * Acquisition modes : Axial, Helical, Step \& Shoot
Hôpital Cardiologique Louis Pradel - Hospices Civils de Lyon
Bron, Avenue Doyen Lépine, France
RECRUITINGquality of the images
A single four-point scale will be used (1: unacceptable, 2: usable under limited conditions, 3: probably acceptable, 4: fully acceptable) based on the European guidelines on quality criteria for computed tomography
Time frame: Day 8
Diagnostic confidence graded
The diagnostic confidence grade will be calculated on a four-point scale (1: insufficient, 2: poor, 3: average, 4: good).
Time frame: Day 8
Subjective image quality graded
It will be calculated on a five-point scale (1: poor, 2: fair, 3: average, 4: good, 5: excellent) for each following criterion: noise, artifacts and sharpness.
Time frame: Day 8
CT Dose Index volumic (CTDIvol)
To determine the radiation dose delivered to the patients during the DECT and SPCCT imaging procedures. The CTDI is an estimation of the dose delivered to the organs for each acquired section that is based on acquisition parameters of a water phantom with a 32 cm diameter. The value is expressed in milligray (mGy).
Time frame: Day 8
Dose Length Product (DLP)
To determine the radiation dose delivered to the patients during the DECT and SPCCT imaging procedures. The DLP is obtained as follows: CTDI \* length of body explored = value in mGy.cm.
Time frame: Day 8
Equivalent dose (mSv)
To determine the radiation dose delivered to the patients during the DECT and SPCCT imaging procedures. The equivalent dose is obtained by multiplying the DLP to the specific organ conversion factor.
Time frame: Day 8
Quantitatively image quality : Noise
The noise by selecting regions of interest (ROI) will calculated.
Time frame: Day 8
Quantitatively image quality : Density
The density (HU) by selecting regions of interest (ROI) will calculated.
Time frame: Day 8
Quantitatively image quality : contrast-to-noise ratio
The contrast-to-noise ratio (CNR) by selecting regions of interest (ROI) will calculated.
Time frame: Day 8
Depiction of anatomical structures of interest
Depiction of anatomical structures of interest will be graded on a four-point scale (1: visualization just possible, 2: unclear borders but different structures already visible, 3: very good visualization, well-defined anatomy, 4: perfect delineation of anatomy).
Time frame: Day 8
Radiation dose
An average radiation dose delivered to the patients for each clinical application will be calculated.
Time frame: Day 8
Statistical comparison between SPCCT and DECT
Statistical comparison between SPCCT and DECT will be performed over all images and anatomical structures globally and also for each clinical application of interest.
Time frame: Day 8
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