Ultra-low-dose CACS in a Large Population (ULDCACSLARGE)

Ultra-low-dose Coronary Artery Calcium Scoring: Evaluation of Prognostic Performance and Impact of Physiological Factors on Quantification in a Large Population

Radiation exposure to patients from CT for CAC scoring has steadily decreased in recent years. This is mainly achieved through lowering tube currents alongside with the introduction of iterative reconstruction algorithms which allow compensating for increased image noise. However, the greatest radiation dose reduction can be obtained by reducing peak tube voltage. Yet lowering peak tube voltage remains challenging because tissue attenuation is closely related to photon energy, thus rendering the established thresholds for calculating CAC scores (i.e. Agatston scores) incomparable if peak tube voltages other than the standard 120 kilovolt peak (kVp) are applied. The investigators have developed novel tube-adapted thresholds for CAC scoring by CT at 80 kVp and 70-kVp tube voltage and have shown that these novel thresholds are valid, yielding results closely comparable to the standard 120-kVp protocol. The present study aims to optimize application of such low-dose scans in a general population through assessment of the impact of physiological patient parameters on image parameters such as image noise which per se may impact the accuracy and feasibility of ultra-low-dose CAC scoring with reduced tube voltage. Furthermore, the prognostic performance of such low-dose CAC scoring will be elucidated.

Study Overview

• Status: Terminated
• Conditions: Coronary Artery Disease
• Intervention / Treatment: Diagnostic test: Ultra low-dose CTAC

• Study Type: Interventional
• Enrollment (Actual): 301
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Zurich, Switzerland, 8091
    • Department of Nuclear Medicine, University Hospital Zurich

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:

• Patients referred for a non-contrast enhanced CT scan for CAC scoring
• Male and Female subjects ≥18 years of age,
• Written informed consent

Exclusion Criteria:

• Pregnancy or breast-feeding
• CACS of 0 after inclusion of 50 patients with CACS 0 (as assessed visually after the first CT scan, prior to performing the 3 additional study scans)
• History of coronary artery stenting, coronary artery bypass grafting, of implantation of cardiac devices (e.g. valve prosthesis, pacemaker, implantable cardioverter defibrillator etc.)
• Enrolment of the investigator, his/her family members, employees and other dependent persons

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Standard and ultra-low-dose CAC scoring	Diagnostic test: Ultra low-dose CTAC; All patients undergo two non-contrast enhanced CT scans with standard dose (i.e. 120 kVp), one with 80 kVp and one with 70 kVp.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Impact of BMI on CAC scores derived from low-dose versus standard-dose CT	Assessment of deviation of CAC scores derived from low-dose CT versus standard-dose CT (i.e. standard of reference) by calculating bias and Bland-Altmann limits of agreement as well as intraclass correlation in different subgroups of patients, stratified by body mass index.	2 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prognostic value of CAC scores derived from CT scans with varying tube voltages	Assessment of sensitivity and specificity CAC scores derived from low-dose CT versus standard-dose CT (i.e. standard of reference) to predict future cardiovascular events (i.e. myocardial infarction, revascularisation, death) over a short to mid-term follow-up period (i.e. 2 years).	2 years

Collaborators and Investigators

• Sponsor: University of Zurich

Publications and helpful links

General Publications

• Grani C, Vontobel J, Benz DC, Bacanovic S, Giannopoulos AA, Messerli M, Grossmann M, Gebhard C, Pazhenkottil AP, Gaemperli O, Kaufmann PA, Buechel RR. Ultra-low-dose coronary artery calcium scoring using novel scoring thresholds for low tube voltage protocols-a pilot study. Eur Heart J Cardiovasc Imaging. 2018 Dec 1;19(12):1362-1371. doi: 10.1093/ehjci/jey019.

Study record dates

Study Major Dates

• Study Start (Actual): July 5, 2018
• Primary Completion (Actual): October 25, 2021
• Study Completion (Actual): October 25, 2021

Study Registration Dates

• First Submitted: July 26, 2018
• First Submitted That Met QC Criteria: August 16, 2018
• First Posted (Actual): August 17, 2018

Study Record Updates

• Last Update Posted (Actual): November 14, 2022
• Last Update Submitted That Met QC Criteria: November 7, 2022
• Last Verified: November 1, 2022

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Myocardial Ischemia; Heart Diseases; Cardiovascular Diseases; Vascular Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Coronary Disease; Coronary Artery Disease
• Other Study ID Numbers: USZ-2017-01158

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