Page 144 - Registrar Orientation Manual 2016

Reference:
1257
Effective date:
7 July 2015
Expiry date:
6 July 2018
Page:
27 of 35
Title:
Imaging Guidelines
Type:
Clinical Guideline
Version:
02
Authorising initials:
The Oncology Unit have developed guidelines for the following (listed alphabetically):
Brain Tumours (Suspected Metastases)
CT is usually the first investigation requested.
If a suspected brain metastasis (or multiple metastases) is (are) detected on CT, MRI may still be indicated for further characterisation and to better assess the full extent of disease.
MRI brain is the most sensitive and specific investigation and is clinically indicated:
• In situations where it is important to assess whether metastases are potentially resectable or suitable for stereotactic radiosurgery. This includes an assessment of the number of metastases.
• In situations where being as confident as possible about the absence of intracranial metastases is important prior to embarking on any other proposed therapy (e.g. a major extra-cranial surgical procedure, chemotherapy)
Clinical urgency: Imaging within 1-2 weeks desirable, to allow important treatment decisions to be made. Greater urgency may exist for neurosurgical indications (e.g. hydrocephalus).
Brain Tumours (Suspected Primary)
CT is usually the first investigation requested.
If a suspected primary brain tumour is detected on CT, MRI (which is more sensitive and specific) should be undertaken for further characterisation and to better assess the full extent of disease.
MRI is clinically indicated:
• T o assess resectability
• T o assess post-resection residual tumour
• To aid radiation therapy planning (with fusion MRI and planning CT, for target volume definition)
Clinical urgency: Imaging within 1-2 weeks is desirable, to allow important treatment decisions to be made. Greater urgency may exist for neurosurgical indications (e.g. hydrocephalus).
Liver and Adrenal Lesions
Liver and adrenal lesions may be identified on ultrasound or CT. Depending on the nature of the abnormality it may be appropriate to further image using a combination of ultrasound or CT.
MRI is clinically indicated in the investigation of abnormalities on other imaging where significant uncertainty about the specific nature of abnormality (e.g. possible metastasis) and where resolving the uncertainty will alter the management plan.
Clinical urgency: Imaging within 1-2 weeks desirable, to allow treatment decisions to be made.
Monitoring of Response to Treatment
Repeated imaging should only occur if it is needed to determine future treatment decisions. CT is the most commonly indicated modality, but plain X-rays (e.g. CXR) may be adequate.
MRI is clinically indicated in the monitoring of response to therapy in situations where it is significantly superior to other imaging options. Some examples (not an exhaustive list) are:
• Patients not suitable for IV contrast
• Liver tumours (primary and secondary)
• Pelvic lymphadenopathy
• Some bone metastases
• Tumours of the orbit
• Brain tumours (primary and secondary)