Comparison of Imaging Quality Between Spectral Photon Counting Computed Tomography (SPCCT) and Dual Energy Computed Tomography (DECT)


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

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: N/A
    • Intervention Model: Single Group Assignment
    • Primary Purpose: Diagnostic
    • Masking: None (Open Label)
  • Study Primary Completion Date: July 29, 2022


  • Device: Spectral Photon Counting Computed Tomography (SPCCT)
    • 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;
  • Device: DECT (Dual Energy CT)
    • 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

Arms, Groups and Cohorts

  • Experimental: SPCCT and standard DECT
    • Comparative intra-patients (each patient will have both types of scanner imaging done), clinical superiority study, evaluating the imaging performances (e.g. image quality and radiation dose) of SPCCT and standard DECT for several body regions/anatomical structures.

Clinical Trial Outcome Measures

Primary Measures

  • quality of the images
    • Time Frame: Day 8
    • 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

Secondary Measures

  • Diagnostic confidence graded
    • Time Frame: Day 8
    • The diagnostic confidence grade will be calculated on a four-point scale (1: insufficient, 2: poor, 3: average, 4: good).
  • Subjective image quality graded
    • Time Frame: Day 8
    • 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.
  • CT Dose Index volumic (CTDIvol)
    • Time Frame: Day 8
    • 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).
  • Dose Length Product (DLP)
    • Time Frame: Day 8
    • 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
  • Equivalent dose (mSv)
    • Time Frame: Day 8
    • 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.
  • Quantitatively image quality : Noise
    • Time Frame: Day 8
    • The noise by selecting regions of interest (ROI) will calculated.
  • Quantitatively image quality : Density
    • Time Frame: Day 8
    • The density (HU) by selecting regions of interest (ROI) will calculated.
  • Quantitatively image quality : contrast-to-noise ratio
    • Time Frame: Day 8
    • The contrast-to-noise ratio (CNR) by selecting regions of interest (ROI) will calculated.
  • Depiction of anatomical structures of interest
    • Time Frame: Day 8
    • 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).
  • Radiation dose
    • Time Frame: Day 8
    • An average radiation dose delivered to the patients for each clinical application will be calculated.
  • Statistical comparison between SPCCT and DECT
    • Time Frame: Day 8
    • Statistical comparison between SPCCT and DECT will be performed over all images and anatomical structures globally and also for each clinical application of interest.

Participating in This Clinical Trial

Inclusion Criteria

  • Patients presenting following one of following medical conditions: 1. Asymptomatic type 1 or 2 diabetes as regard to cardiovascular risks 2. Diabetic foot ulcer 3. Adrenal glands lesions: Adrenal incidentaloma or hyperaldosteronism or macroadenoma 4. Urinary stone(s) 5. Known Coronary artery disease: Stent imaging or control of calcified plaques 6. Diffuse Interstitial Lung Diseases: Idiopathic Pulmonary Fibrosis, Hypersensitivity Pneumonitis, Ground Glass Opacification, Chronic Thromboembolic Pulmonary Hypertension 7. Conductive hearing loss 8. Brain stroke (late or post thrombectomy) 9. Intracranial arteriovenous malformation treated with coils or Onyx 10. Joints diseases in haemophilia – Patient has accepted to participate to the study and has signed the written consent; – Pre-menopausal women only: Negative urinary pregnancy test on the day of imaging before the administration of study drug; – Patient is affiliated to the French social security Exclusion Criteria:

  • Contraindication to the use of iodine containing contrast media (including subjects with suspicion for/or known to have NSF) (if injection); – History of severe allergic or anaphylactic reaction to any allergen including drugs and contrast agents (as judged by the investigator, taking into account the intensity of the event); – History of delayed major or delayed cutaneous reaction to Iomeron injection – Estimated Glomerular Filtration Rate (eGFR) value < 30 mL/min/1.73 m2 derived from a serum creatinine result within 1 month before the imaging for examinations with contrast agent. – Any subject on hemodialysis or peritoneal dialysis; – Suspected clinical instability or unpredictability of the clinical course during the study period (e.g. due to previous surgery); – Pregnant or nursing (including pumping for storage and feeding); – Patient under guardianship, curatorship or safeguard of justice.

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Hospices Civils de Lyon
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Philippe DOUEK, Pr, Principal Investigator, Service de Radiologie, l’Hôpital Louis Pradel – Hospices Civils de Lyon
  • Overall Contact(s)
    • Philippe DOUEK, Pr, 04 72 07 18 83,

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