How can we detect pml?

Diagnosis PML. The diagnosis is usually made by the finding of jacob-creutzfeld virus in the spinal fluid or brain biopsy. Mri findings show multifocal non enhancing lesions without mass effect in the brain's cortical white matter.
MRI & biopsy. The pattern on MRI of the brain can be very suggestive, but a biopsy (surgery to get brain tissue to examine) is the only way to definitively diagnose it.