Lumbar disc disease
In symptomatic cases the diagnosis should be confirmed by an MRI scan. However, in cases with slight symptoms, a faster and cheaper CT scan (although it is inferior to MRI scan) may be recommended. While a CT scan can show the bony structures in more detail, an MRI scan can better portray soft tissue.
Neurovirology
CT scans and MRI scans are useful in visualizing inflammation and lesions caused by viral infection of the CNS. MRI is used to visualize deep white matter and temporal lobe lesions, which are not well defined by a CT scan.