Cardiac CT at Parkside Hospital

Parkside Hospital offers Cardiac CT investigations. Our GE 64-slice scanner allows prospective acquisition of data, which results in a significant dose reduction compared to previously available software. The radiation dose is now comparable to that of a conventional coronary angiogram, but in a non-invasive out-patient setting, with less attendant risk.

In order to make the best use of our technology, it is essential that patients have a slow, steady heart rate, preferably of less than 60 beats per minute.

To achieve this, we feel that unless it is contra-indicated, all patients referred for cardiac CT should have an oral beta blocker prior to the study. A dose of 25-100mg of metoprolol taken orally 3 hours before the scan should provide the desired bradycardia. Please prescribe this when referring your patient.

If you feel that oral beta-blockade is not appropriate, please note this on your referral letter and also whether the administration of iv metprolol, which is our current practice, is also not appropriate.

• The team at Parkside Hospital follow the 2010 NICE Guidance in investigating patients who present with chest pain. The imaging choices are based on stratification of risk of coronary artery disease.
• Low risk patients may be investigated with a non- invasive low dose CT coronary angiogram.
• Intermediate risk – Functional imaging by either MRI or radionuclide stress scintigraphy.
• Patients with a High Risk of coronary artery disease – conventional coronary angiogram which provides the option of immediate intervention.
• Calcium scoring is an integral component of the CT coronary angiogram. A low dose unenhanced scan is used to plan the start and end positions of the CT coronary angiogram.
• If the Agaston Score is high (greater than 1,500) the diagnostic value of CT is reduced and the patient proceeds to conventional angiography.
• Older patients ( > 65years) with an Agaston Score of less than 100 are unlikely to have significant coronary artery disease.
• In young patients (40’s and 50’s) a score of zero may be falsely reassuring as significant non-calcified plaque may exist in the absence of calcified plaque in this age group.
• The total dose for CT is now of the order of 2-6 mSv depending on protocol. This compares favourably with conventional angiography. Average background radiation in the UK is 2.5 mSv (7.5 mSv in Cornwall).
• Better image quality and low dose is achieved if the patient’s heart rate is steady and low (50-70 beats per minute). A prospective gated protocol is usually used, where the xrays are switched on for only a small portion of the cardiac cycle.

Patient Preparation

• There is a patient information sheet (Please click here)
• Studies are best performed on a dedicated list (less chance of patient anxiety and increased heart rate).
• Specialist referral from Cardiologists or specialist Physicians to ensure appropriate patient selection.
• Patients may be started on oral beta blockade when referred by Cardiologists. A small dose of iv beta blockade (metoprolol 5-20 mg) may be given immediately prior to scanning if heart rate elevated.

What to expect

• Parkside perform over 1,000 contrast enhanced CT’s per year. CT coronary angiography is a non- invasive outpatient procedure.
• 18G or 20G cannula preferably right antecubital fossa.
• Low-osmolar non-ionic iodinated contrast medium and normal saline.
• ECG Leads
• Total time in room of 20 minutes.
• Acquisition time of just under 10 seconds.
• Patient stays in Radiology department for 30 minutes after injection of contrast medium.
• Results to referrer on same day.