Page 134 - Registrar Orientation Manual 2016

Reference:
1257
Effective date:
7 July 2015
Expiry date:
6 July 2018
Page:
17 of 35
Title:
Imaging Guidelines
Type:
Clinical Guideline
Version:
02
Authorising initials:
Contraindications to cardiac MRI include:
• unstable patients (cardiac MRI is currently performed off campus)
• renal impairment eGFR <30
• over 130kg
• non cardiac MRI capable pacemakers or defibrillators
Clinical Urgency: CTCA and cardiac MRI are usually performed as outpatient investigations.
The ‘Choosing Wisely’ recommendations include:
Don’t perform cardiac imaging for patients who are at low risk.
Don’t perform cardiac imaging as a pre-operative assessment in patients scheduled to undergo low- or intermediate-risk non-cardiac surgery.
Don’t perform radionuclide imaging as part of routine follow-up in asymptomatic patients.
Don’t perform stress cardiac imaging or advanced non-invasive imaging in the initial evaluation of patients without cardiac symptoms unless high-risk markers are present.
Use methods to reduce radiation exposure in cardiac imaging, whenever possible, including not performing such tests when limited benefits are likely.
Don’t use coronary artery calcium scoring for patients with known CAD, for preoperative evaluation for any surgery, irrespective of patient risk, for screening purposes on low risk asymptomatic individuals.
Don’t routinely order coronary computed tomography angiography for screening asymptomatic individuals or in high risk patients presenting with acute chest pain.
Suspected Colon Cancer
CT colonography has replaced barium enema as the radiological imaging modality for the colon but colonoscopy still remains the investigation of choice for most patients with suspected colon cancer.
The National Community Radiology Access Criteria have these indications for CT colonography:
• symptomatic patients over 80 years
• patients with co-morbidities when colonoscopy presents a higher risk
• patients presenting with abdominal mass
• following failed or incomplete colonoscopy
• patients with symptoms which are average to low risk for malignancy
They include that referral for CT colonography is not typically indicated (ie, refer for colonoscopy):
• diarrhoea as the predominant presenting symptom
• known polyp syndromes (including familial) where biopsy/removal is likely to be required
• suspected IBD where mucosal visualisation and biopsy are required for diagnosis
• young patients (< 40 years)
At Waikato we are unable to offer CT colonography for all these indications.
We use the National Referral Criteria for Direct Access Outpatient Colonoscopy, developed in 2012, to triage referrals for colonoscopy and have adapted these for CT colonography.
Patients with a history of metallic implants / shrapnel / prior neurosurgical clip placement require evaluation prior to MRI (with documentation of the items on the request form).
All requests need to be on the Midland MRI request form and sent to Dr Mark Davis’ secretary (Mrs Carmel Clifton, fax 07 8398639, following phoning her on 98301) for review by Dr Mark Davis. Consultant to consultant discussion will frequently be required.