Ultra Low Dose CT for CACS and AC of SPECT

Study Overview
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Brief Summary
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The aim of the study is to compare the CACS obtained from standard dose CT to the CACS obtained from ultra-low-dose scans. Additionally, the usefulness of ultra-low-dose CT for AC of myocardial perfusion SPECT will be assessed.

Official Title
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Usefulness of Ultra Low Dose Cardiac CT for Coronary Calcium Scoring and for Attenuation Correction of SPECT

Conditions
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Coronary Artery Disease

Intervention / Treatment
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* Device: Ultra low dose non-contrast enhanced CT
* Device: Standard dose non-contrast enhanced CT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients referred for myocardial perfusion SPECT Male and Female subjects ≥18 years of age, Written informed consent Exclusion Criteria: Pregnancy or breast-feeding CACS of 0 after inclusion of 10 patients with CACS 0 Stents or implanted cardiac devices (valves, pace makers, ICD) Coronary artery bypass grafts

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Standard dose CT, Ultra-low dose CT<br>Standard dose non-contrast enhanced CT (clinically indicated) and Ultra low dose non-contrast enhanced CT (as part of the trial) | Device: Ultra low dose non-contrast enhanced CT<br>* Non-contrast enhanced CT for CACS and AC using a novel protocol for ultra low dose radiation dose exposure<br>Device: Standard dose non-contrast enhanced CT<br>* Clinically indicated non-contrast enhanced CT for CACS and AC according to routine protocol<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Agreement and Correlation of Coronary Artery Calcium Score Obtained From Ultra-low-dose and Standard CT | CAC and BA limits of agreement between coronary artery calcium score obtained from ultra-low-dose and standard CT. Coronary artery calcium (CAC) is a measure for quantification of coronary artery calcification based on non-contrast enhanced CT, ranging from 0 (no calcifications) to infinite. It is an arbitrary unit. Increasing CAC means higher amounts of coronary artery calcifications and is associated with worse prognosis. Bland-Altman (BA) analysis is a statistical method to compare two modalities or techniques assessing the same measure. Limits of agreement is defined as +/- twice the standard deviation of the differences between the reference method and the new modality/technique. Broader limits of agreement mean less accurate results obtained by the new modality/techniqe, while a 0 BA limit of agreement would theoretically reflect perfect agreement. | 1 days | 
| Intra-class Correlation Coefficient Between Segmental Relative Tracer Uptake From SPECT Datasets Reconstructed With AC Maps Based on Ultra-Low-Dose and Standard Dose CT | For every patient, the CT images from 120 and 70 kVp-CT scans were used to create CTAC maps which were then used to reconstruct SPECT images, displayed as a 17-segment model polar plot with normalized percent tracer uptake given for every segment. Intra-class correlation was then applied to compare segmental relative tracer uptake. Analysis and the resulting correlation coefficient of 0.987 basically demonstrates interchangeability between the two datasets. | 1 day |