Ultra Low Iodine Loaded Spectral CT Angiography (CTA)

Ultra Low Iodine Loaded Spectral CT Angiography (CTA) of the Aorta and Lower Limb: A Randomized Controlled Trial

The objectives of this study are:

Evaluation of ultra-low iodine load CTA protocols of the aorta and lower extremities.

To investigate whether dual-layer in combination with with virtual monoenergetic imaging (VMI) allows for reduction of contrast medium (CM) in CTA of the aorta and lower limbs i with sustained objective and subjective image quality parameters.

Study Overview

• Status: Completed
• Conditions: Renal Insufficiency; Peripheral Arterial Disease
• Intervention / Treatment: Diagnostic test: Half iodine Spectral CT; Diagnostic test: Standard iodine conventional CT

Detailed Description

CT angiography (CTA) of the aorta and the lower limb is one of the most important tools for diagnostic, evaluation of the severity of the peripheral arterial disease, decision making, treatment planning and follow-up; but usually requires the use of iodine contrast medium.

Due to the high prevalence of renal impairment (eGFR < 90 ml/min/1.73m) in the elderly hospitalized population (more than 90% among inpatients aged over 60 years) contrast-medium-induced nephropathy is a major concern in this population.

The recently introduced spectral CT technique utilizes x-rays covering a spectrum of energy-levels as opposed to conventional CT in which x-rays are set to one specific energy level.

This technology offers many possibilities, such as "boosting" the x-ray contrast effect of iodine. This improves the vascular enhancement of the contrast medium using low-energy, virtual monoenergetic imaging (VNI).

The objectives of this study are:

Evaluation of ultra-low iodine load CTA protocols of the aorta and lower extremities.

To investigate whether dual-layer in combination with with virtual monoenergetic imaging (VMI) allows for reduction of contrast medium (CM) in CTA of the aorta and lower limbs i with sustained objective and subjective image quality parameters.

• Study Type: Interventional
• Enrollment (Actual): 216
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Norway
  • Viken
    • Lørenskog, Viken, Norway, 1478
      • Akershus University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Inpatients and outpatients with kidney function (eGFR) allowing for safe administration of standard contrast dose (as calculated with the OmniVis calculator).
• Patients with clinical suspicion of disease of the aorta and/or arteries in the lower limb.
• Referral to CTA diagnosis, treatment planning or follow-up.

Exclusion Criteria:

• Iodine contrast medium allergy
• Age < 18 years
• Lack of informed consent
• Critical ischemia of the lower extremities

Study Plan

How is the study designed?

Design Details

• Primary Purpose: DIAGNOSTIC
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: SINGLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Half iodine - Spectral CT group; Patients receive half dosage of iodine contrast agent, and Spectral CT acquisition with Virtual Monoenergetic Images at 40 and 50 kiloelectronVolts (keV).	Diagnostic test: Half iodine Spectral CT; Patients receive half dosage of iodine contrast agent, and Spectral CT acquisition with Virtual Monoenergetic Images at 40 and 50 keV.
ACTIVE_COMPARATOR: Standard iodine - Conventional CT; Patients receive standard dosage of iodine contrast agent, and conventional 120 kiloVolts (kV) polychromatic CT images	Diagnostic test: Standard iodine conventional CT; Patients receive standard dosage of iodine contrast agent, and conventional 120 kv Polychromatic CT acquisition.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean arterial attenuation	Attenuation (x-ray density) is measured in Hounsfield units (HU) digitally by placing a "region of interest" (ROI) circle in the Aorta, common iliac-, femoral- and popliteal arteries on the CT images acquired at the time of inclusion.	Measured on CT images acquired at time of inclusion

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Subjective examination quality	Examination quality rated by interventional radiologists on a 4-point scale at the anatomic levels: aorta, common iliac, femoral, popliteal- and calf arteries. Subjective examination quality rating scale: (best) - Excellent: The demarcation of the vessel lumen is excellent, more than sufficient for confident diagnosis or exclusion of stenosis or occlusion.; - Good: The demarcation of the vessel lumen is sufficient for confident diagnosis or exclusion of stenosis or occlusion.; - Adequate: The demarcation of the vessel lumen is adequate for diagnosis or exclusion of stenosis or occlusion, but with limited confidence.; (worst) - Non-diagnostic: There is insufficient demarcation of the vessel lumen for diagnosis or exclusion of stenosis or occlusion.	Rated on CT images acquired at time of inclusion
Rate of diagnostic quality angiography	Based on measurements of attenuation in the aorta, common iliac-, femoral- and popliteal arteries. Diagnostic quality defined as arterial attenuation >200 Hounsfield units (HU)	Measured on images acquired at time of inclusion

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Image noise	Image noise was defined as the standard deviation of arterial attenuation measurements (see outcome 1) measured in HU digitally by placing a ROI on the CT-images in the aorta, common iliac-, femoral- and popliteal arteries.	Measured on CT-images acquired at time of inclusion
Contrast to noise ratio (CNR)	Contrast to noise ratio was defined as: (Arterial attenuation - Background attenuation) / Image noise Arterial attenuation: (see outcome 1) measured in HU digitally by placing a ROI on the CT-images in the aorta, common iliac-, femoral- and popliteal arteries. Background attenuation: defined as attenuation in muscle measured in HU digitally by placing an identical size ROI on the CT-images in muscle tissue at the same anatomical levels as the arterial measurements. Image noise: see outcome 4	Measured on CT-images acquired at time of inclusion
Signal to noise ratio (SNR)	Signal to noise ratio was defined as: Arterial attenuation / Image noise Arterial attenuation: (see outcome 1) measured in HU digitally by placing a ROI on the CT-images in the aorta, common iliac-, femoral- and popliteal arteries. Image noise: see outcome 4	Measured on CT-images acquired at time of inclusion

Collaborators and Investigators

• Sponsor: University Hospital, Akershus
• Collaborators: Oslo Metropolitan University
• Investigators: Principal Investigator: Peter M Lauritzen, MD PhD, University Hospital, Akershus & Oslo University Hospital

Study record dates

Study Major Dates

• Study Start (ACTUAL): January 28, 2019
• Primary Completion (ACTUAL): October 16, 2020
• Study Completion (ACTUAL): October 16, 2020

Study Registration Dates

• First Submitted: June 21, 2022
• First Submitted That Met QC Criteria: August 3, 2022
• First Posted (ACTUAL): August 5, 2022

Study Record Updates

• Last Update Posted (ACTUAL): August 5, 2022
• Last Update Submitted That Met QC Criteria: August 3, 2022
• Last Verified: August 1, 2022

More Information

Terms related to this study

• Keywords: Contrast Media; Computed Tomography Angiography
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Kidney Diseases; Urologic Diseases; Atherosclerosis; Peripheral Arterial Disease; Peripheral Vascular Diseases; Renal Insufficiency; Physiological Effects of Drugs; Anti-Infective Agents, Local; Anti-Infective Agents; Trace Elements; Micronutrients; Iodine; Cadexomer iodine
• Other Study ID Numbers: 2018_070

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No