Comparison of Image Quality of Coronary Computed Tomography Angiography bEtweeN High concenTRATion and Low concEntration Contrast Agents(CONCENTRATE Trial)

Study Overview
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Brief Summary
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According to CT technology development, cardiac CT is very useful examination as noninvasive examination and the accuracy in locating lesions has increased to 95%. Specifically, cardiac CT has been performing a gateway role in reducing invasive cardiac angiography implemented solely for the purpose of diagnosis because of the invasive testing of makeshift cardiac angiography. However, cardiac CT also comes with the disadvantage that patients cannot avoid being exposed to radiation, so there has been much effort in appealing to reduce exposed radiation dose. Of these methods, the most effective is the method of repeatedly reconstitution by way of synchronized prospective ECG while using low tube-based potential. According to recent studies, the SNR(Signal Noise Ratio) and CNR(Contrast Noise Ratio) values representing image quality have been higher compared to the combined method of image reconstruction by makeshift filtered back projection and condition of image acquisition by patient BMI. Also, the administered amount of contrast agent can be reduced for achieving the same contrast effect due to the advantage of the increased effect of contrast enhancement by using low tube voltage. Therefore, the efficacy studies of using low concentration of contrast agents in conditions of using low tube voltage are being processed. This study intends to prove that image quality does not deteriorate by suitable image reconstruction method with low concentration contrast agent compared to the combined method of the makeshift filtered back projection image reconstruction method and the conditions of image acquisition according to BMI with general amount of contrast agent.

Conditions
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Coronary Artery Disease

Intervention / Treatment
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* Procedure: CT angiography with high concentration contrast agent
* Procedure: CT angiography with low concentration contrast agent (320)
* Procedure: CT angiography with low concentration contrast agent (270)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults at least 20 years old Subject who had requested a coronary CT angiography as per a clinical disease Exclusion Criteria: Subject suspected as having myocardial infarction, unstable angina pectoris, coronary artery disease Subject with heart attack within 40 days prior to the CT scan Subject with diagnosed complicated heart anomaly BMI (body mass index) > 35kg/m2 Serum creatinine ≥1.5mg/dl of renal insufficiency Subject with pregnancy or unknown pregnancy Subject with history of hypersensitivity reaction of contrast agents Subject has contraindication of using nitroglycerine Subject has plan to participate or enrolled in other randomized clinical trial for cardiovascular disease. Subject has contraindication of using adenosine (e.g. bronchial asthma, 2-3 degree AV block, sick sinus syndrome, SBP (systolic blood pressure) less than 90mmHg, recent prescribed history of dipyridamole, hypersensitivity of adenosine)

Ages Eligible for Study
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Minimum Age: 20 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
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: High concentration (370)<br>CT angiography with hign concentration iodine contrast agent of 370 mg iodine/ml | Procedure: CT angiography with high concentration contrast agent<br>* Standard concentration of iodine contrast agent for CT<br>|
| Experimental: Low concentration (320)<br>CT angiography with low concentration iodine contrast agent of 320 mg iodine/ml | Procedure: CT angiography with low concentration contrast agent (320)<br>* Two interventional arms use two different low concentration of iodine contrast agents, which is 320mgI/ml and 270mgI/ml respectively.<br>|
| Experimental: Low concentration (270)<br>CT angiography with low concentration iodine contrast agent of 270 mg iodine/ml | Procedure: CT angiography with low concentration contrast agent (270)<br>* Two interventional arms use two different low concentration of iodine contrast agents, which is 320mgI/ml and 270mgI/ml respectively.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assess HU (Hounsfield unit) for image quality of 3 different protocol of contrast media in coronary CT angiography |  | 7 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Qualitative evaluation of image quality of coronary artery | Measurement of evaluable segment with 4 point grading system as visual assessment | 7 days | 
| Quantitative analysis of image quality using measuring HU | Measurement of HU (Hounsfield unit) of myocardium during adenosine stress test in static perfusion CT | 7 days | 
| Diagnostic accuracy of coronary CT angiography compared to invasive coronary angiography | On segment-basis analysis, sensitivity, specificity, positive negative predictive value, negative predictive value, and accuracy of CT angiography for diagnosis of presence of CAD which is defined by more than 50% diameter stenosis compared to invasive coronary angiography, will be calculated and compared between different concentration of contrast agents by means of generalized estimating equation based on binary logistic model. | 7 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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low concentration contrast agent, Low dose contrast agent, computed tomography