None listed
Conditions
Brief summary
Nuclear medicine myocardial perfusion imaging is currently indicated in patients with symptoms of cardiac ischaemia, who have either failed a stress echocardiogram, are unable to exercise to the extent required to provide an adequate stress echocardiogram or have a body habitus or other physical condition that would prevent an adequate stress echocardiogram. A nuclear medicine myocardial perfusion scan consists of an intravenously administered radioisotope, which can then be assessed with either single photon emission computer tomography (SPECT) or positron emission tomography (PET). This allows the assessment of the underlying myocardium and the underlying coronary arteries. More recently coronary artery calcium (CAC) scoring has been developed to assess patients without known coronary artery disease who present with symptoms of acute ischaemia and are of low or intermediate risk, without electrocardiograph changes or elevation in cardiac biomarkers. As both investigations utilise computed tomography (CT), our aim is to assess the value of coronary artery calcium scoring on nuclear medicine myocardial perfusion scans, in order to improve the diagnosis and outcomes in patients with low to intermediate risk cardiac ischaemia. Currently there is no research available on the utility of coronary artery calcium scoring in myocardial perfusion scans. The investigators aim to show a correlation of the coronary artery calcium score between the computed tomography conducted for myocardial perfusion imaging and dedicated computed tomography imaging. This will then allow the assessment of the coronary artery calcium score retrospectively in participants who underwent myocardial perfusion imaging to assess the change in predefined outcomes when utilising the additional measure.
Interventions
To assess the correlation between the coronary artery calcium score on myocardial perfusion scans versus on dedicated computed tomography coronary angiography, participants who have had myocardial perfusion imaging will be required to subsequently have a dedicated computed tomography coronary angiography scan for coronary artery calcium scoring.
The additional computed tomography coronary angiography has additional radiation exposure. The radiation exposure involved in myocardial perfusion ima
To assess the correlation between the coronary artery calcium score on myocardial perfusion scans versus on dedicated computed tomography coronary angiography, participants who have had myocardial perfusion imaging will be required to subsequently have a dedicated computed tomography coronary angiography scan for coronary artery calcium scoring. The additional computed tomography coronary angiography has additional radiation exposure. The radiation exposure involved in myocardial perfusion imaging has been found to be between 10-20 millisieverts, whereas the radiation exposure for a dedicated coronary artery calcium score CT is 1 millisievert. The average Australian background radiation exposure per year is 1.5-2milliseverts. Participants will undergo the dedicated computed tomography coronary angiography within 2 weeks of having their myocardial perfusion scan. The computed tomography coronary angiography will be undertaken at the same centre (Tamworth Rural Referral Hospital), and take approximately 30 minutes. The scan will be completed by a trained diagnostic radiographer at the centre. The computed tomography coronary angiography includes the administration of a contrast agent Iohexol (Omnipaque Trade Name) via intravenous infusion. The administered dose will be between 0 to 100mls and be determined by the diagnostic radiographer at the time of the scan and based on patients body habitus, to ensure an optimal scan. Participants may also require the administration of a heart rate controlling medication, metoprolol, to achieve an optimal heart rate of approximately 60 beats per minute for the scan. The computed tomography coronary angiography and myocardial perfusion computed tomography scans will be assessed at the same centre by the researchers to determine whether there is a correlation between the two coronary artery calcium scores. Patients who do not undergo the dedicated computed tomography coronary angiography will be excluded from the study. This will be determined by the absence of a dedicated computed tomography coronary angiography at the time of conducting the coronary artery calcium scores on the respective images. All participants will undergo the same intervention. The amount of the contrast agent, the requirement for metoprolol for rate control and the dose of radiation from the computed tomography scan will vary between patients. Each of these will be noted in the data collection and in the reporting of the study.
Sponsors
Shanathan Sritharan
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Diagnosis
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
The inclusion criteria will include any patient over the age of 18 years of age, who has presented with symptoms of cardiac ischaemia that has been deemed to be low to intermediate risk.
Exclusion criteria
The exclusion criteria for this phase is any patient with known coronary artery disease defined as previous cardiac surgical intervention, percutaneous coronary intervention, any patient with a congenital cardiac condition, recent myocardial infarction defined by changes to electrocardiography and cardiac biomarkers, myocarditis and/or moderate to severe valve calcification which would impair coronary artery calcium scoring, as well as any condition that would prevent patients undergoing a myocardial perfusion or computed tomography.
Outcome results
None listed