Page 132 - Registrar Orientation Manual 2016

Reference:
1257
Effective date:
7 July 2015
Expiry date:
6 July 2018
Page:
15 of 35
Title:
Imaging Guidelines
Type:
Clinical Guideline
Version:
02
Authorising initials:
The ‘Choosing Wisely’ recommendations for investigation of back pain include:
Don’t obtain imaging (plain radiographs, MRI or CT, or other advanced imaging) of the spine in patients with non-specific acute low back pain who not have red flags (severe or progressive neurologic deficits or a suspected serious underlying condition (such as vertebral infection, cauda equina syndrome, or cancer with bony metastasis).
Don’t do a MRI of the spine or brain for patients with only peripheral neuropathy (without signs or symptoms suggesting a brain or spine disorder).
Bowel Obstruction.
The Australian imaging guidelines have pathways for Bowel Obstruction.
Plain X-rays should be done first and further imaging based on the clinical picture and X-ray findings.
Further imaging may not be needed in small bowel obstruction with suspected adhesions but CT may be indicated for large bowel obstruction not due to constipation with faecal loading.
Clinical urgency: Usually as soon as possible depending on the acuity. After 2200, the urgency will need to be discussed with the on call radiology registrar. If a patient does not have signs of an acute abdomen, they should be admitted and a CT scan usually be deferred until the following morning.
Brain Masses (Diagnosis - see also Malignancy)
CT with contrast will usually establish the presence of a mass but MRI/A is usually needed before
treatment. Further imaging may not be appropriate if the patient is not for any intervention.
It can be difficult with a solitary lesion to differentiate between a 1° and 2°. Metastatic disease needs to be ruled out if considering neurosurgery. Look for a possible 1° and 2° elsewhere.
Consider CT chest/abdomen before doing a MRI if 2° are likely, but only if it is appropriate to establish a 1° site and/or get a tissue diagnosis and it will affect treatment.
Clinical Urgency: Most brain masses are identified in imaging done for suspected stroke, TIA or headache. An urgent CT may be indicated if there is a reduced level of consciousness. Further imaging with CT chest/abdomen or MRI to guide treatment should usually be within 48 hours.
Cardiac Disease and Chest Pain
In New Zealand exercise stress ECG testing remains the first line investigation in most patients with suspected low to medium risk ACS, to aid with further risk stratification and decide who needs further tests, including angiography, myocardial perfusion imaging and CT angiography
CT Coronary Angiography (CTCA)
CTCA in Waikato must be requested by a cardiologist and is offered only for these criteria:
• evaluation of ischaemic sounding symptoms in an outpatient setting, if another modality such
as exercise stress testing has been equivocal or indeterminate
• evaluation of anomalous coronary anatomy
• evaluation of coronary grafts
• evaluation of anatomy in selected chronic occlusive CAD cases for planned interventions or in
planning for a small number of other complex intervention cases
• evaluation for an ischaemic cause of cardiomyopathy (EF<40%, no regional wall motion
abnormality) when suspicion of ischaemia is not high, in place of invasive angiography
CTCA still requires contrast. Contraindications to CTCA at WDHB include:
• atrial fibrillation
• renal impairment eGFR <30
• contrast allergy (relative)
• severe calcification