Clinical trial NCT03637231: Ultra-low-dose CACS in a Large Population
Official title: Ultra-low-dose Coronary Artery Calcium Scoring: Evaluation of Prognostic Performance and Impact of Physiological Factors on Quantification in a Large Population
Study type: INTERVENTIONAL
Overall status: TERMINATED
Phase: NA
Conditions: Coronary Artery Disease
Lead sponsor: University of Zurich
Sponsor class: OTHER
First posted: 2018-08-17
Enrollment: 301
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SEQUENTIAL
Primary purpose: DIAGNOSTIC

Brief summary: 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.


Eligibility criteria: 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

Primary outcomes:
measure: Impact of BMI on CAC scores derived from low-dose versus standard-dose CT
timeFrame: 2 years
Secondary outcomes:
measure: Prognostic value of CAC scores derived from CT scans with varying tube voltages
timeFrame: 2 years
Other outcomes:
Locations:
city: Zurich
country: Switzerland
facility: Department of Nuclear Medicine, University Hospital Zurich
Study officials:
References:
citation: 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.