Non contrast:
· Nodules
· Abnormal chest x-ray
· Small airways infection
· Bronchiectasis
· Emphysema
Contrast:
· Adenopathy
· Staging malignancy
· Sarcoid –may want to ask for thin section inspiration 1mm ( not always necessary to do HRCT unless ordered by Pulmonologist)
CTA: Aorta, PE. No need to do pre unless looking for acute intramural hematoma or looking at stent grafts.
HRCT: Ideally for assessment of ILD
· Asbestosis
· UIP
· NSIP
· HP
· Use HRCT questionnaire if you feel unsure.
Low dose:
· Want to know that there is a documented prior showing nodules
· Follow-up nodules
· If there is anything else: i.e. nodules + adenopathy: may need routine dose.
Lung cancer screen: specific protocol Smokers for screening (i.e. 29+ pack years)
NB: Can always get retro recon thin sections,
Ideally ALARA on dose that means no non-contrast UNLESS there is a need:
We need non cons:
· CT renal mass where you need non contrast to make a decision on enhancement.
· CT adrenals
· CT IVU: here the pre is done low dose with routine dose post.
So based on ACR AC criteria and LI-Rads we are going away from doing pres on
- Pancreas mass
- Liver mass
We are also going towards MR for the following:
· Liver mass: characterization is best with MR.
· For F/U cystic pancreatic lesions: MR pancreas which includes thin section MRCP for pancreatic duct.
· For renal masses: solid/ cystic: MRI best to evaluate for solid nodules within cystic lesions and getting tumor/cortex SI ration may help differentiate clear cell, papillary and chromophobe, nuance in that chemotherapy differs for each.
· MRE: ideally if the patient is young and has known Crohn Dz.
# of phases: portal phase is sufficient on most CRC, breast, lung, bladder, prostate, testicular mets etc. Rarely, you can do 2 phases for hypervascular primary lesions: art/ portal phase for carcinoid, melanoma, neuroendocrine tumor metastases.
CTE
· Single phase: Crohn disease: adults or in acute phase.
· To evaluate bowel when EGD and colonoscopy negative but complains of diarrhea/ abdominal pain.
· Double phase: occult GI bleed/ Fe deficiency anemia.
CTIVU
· Split bolus technique is best for assessment and keeps dose down. Caoili (U Michigan)
Low dose CT KUB
Ideally, only want this on patients who have a DOCUMENTED imaging study CT, US or KUB with stones and are following stone burden.