Screening for brain metastasis in patients with stage III Non-Small Cell Lung Cancer: Has Magnetic Resonance Imaging an additive value compared to contrast enhanced Computed Tomography of the brain Incorporated in the staging whole body 18FDG-PET-CT scanning?

In current NSCLC guidelines imaging of the brain is advised in all stage III patients eligible for therapy with curative intent. MRI is preferred to contrast enhanced CT of the brain (CE-CT), but this advise is based on older studies. These studies did not include only (stage III) NSCLC nor 18FDG-PET. In a recently performed retrospective study using up-to-date MRI and CT techniques, no additional brain metastasis were found on MRI in patients with stage III NSCLC after 18FDG-PET-CT with CE-CT of the brain. Moreover, in most hospitals MRI availability is scarce and MRI is difficult to obtain within a reasonable time scale. Also, MRI adds extra costs to the diagnostic evaluation. Finally, there are also some contra-indications for MRI, for example intracorporal metallic objects, pacemakers and claustrophobia.



Although it is known that MRI of the brain is more sensitive than a CE-CT, it is unclear whether this is still the case in the setting of excluding brain metastasis in neurological asymptomatic patients with stage III NSCLC.

The question whether post contrast MRI offers a benefit to CE-CT in the initial staging of patients with NSCLC has become more urgent in view of the increasing wide-spread use of 18FDG-PET-CT scanners. If CE-CT performed in the same setting as 18FDG-PET-CT could lead to the same yield of brain metastasis detection as 18FDG-PET-CT with LD-CT and separately a post contrast MRI, a substantial gain in time and resources can be expected without increasing the radiation dose and quantity of contrast agent administered to the patient.



We hypothesise that there is no clinically relevant additive value of post contrast MRI to CE-CT of the brain when both are performed in standard work-up, including 18FDG-PET-CE-CT, in detecting asymptomatic brain metastasis.

We hypothesise that there is no clinically relevant additive value of post contrast MRI to contrast enhanced computed tomography (CE-CT) of the brain when both are performed in standard work-up, including 18FDG-PET-CE-CT, in detecting asymptomatic brain metastasis.



Clinically relevant is defined by our study group as: additional brain metastasis found on MRI in more than two out of one hundred patients who have a negative 18FDG-PET-CE-CT. We base this number on the fact that already up to 15% of stage III NSCLC patients develop symptomatic brain metastasis within a year after an initial negative MRI.

Follow up will be one year.

None, observational.