Imaging studies during chemotherapy: CT vs MRI vs PET-CT

Hi Inthefight,

You asked about which scanning mode is best for cholangiocarcinoma.  My expertise is as a patient who asks a lot of questions to my doctors, and from learning from the experiences of other patients and their caregivers.

Usually the oncologist selects the scanning mode based on what he or she is trying to look at.  Most of our patients seem to be sent for chest-abdomen-pelvis CT scans, although sometimes MRI is used if there is reason to focus on the liver.  The choice seems to involve which features of the liver and other parts of the anatomy the doctor wants to examine in detail.  The most common sites of metastasis for cholangiocarcinoma include in the liver, lymph nodes, lungs, bones and peritoneum, so the hunt for metastasis will look at these areas, as well as any other areas the doctor is worrying about based on what he or she hears from the patient.

PET scans seem to be reserved for when there are indicators the cancer is spreading, and the oncologist is looking for where new metastases might be appearing.  Sometimes if a CT scan is inconclusive, an MRI or PET scan will be ordered to clarify any concerning features that show up on the CT scan.

So my impression is that one type of scan is not always better than another – the choice depends on the purpose of the scan at the time it is ordered.  Doctors will listen to patient and caregiver input regarding the type and frequency of scans, but may resist some scanning if in the oncologist’s judgment it will not add any additional information.  In addition to the cost, the radiation and contrast agents create risks for patients, so doctors would tend to discourage scanning that seems not to offer sufficient benefit for the patient.

Regards, Mary