PET studies of patients with partial epilepsy: visual interpretation vs. semi-quantification/quantification.

One of the advantages of PET is to allow for precise regional measurements of radioactive tracers in slices of brain. Furthermore, complex compartment modelling methods have been designed to transform the regional radioactive concentrations into biological units. The question is often raised whether quantification of PET studies is necessary in clinical practice. In epileptology, the regional biochemical changes associated with temporal lobe epilepsy are easily detected by experienced eyes and quantification is not required for diagnosis purposes. By contrast, inter-patient or inter-population comparisons can only be performed if regional measures have been obtained; if the PET method has been previously validated, simple measurements (regional activity) are sufficient and (kinetic) compartmental modelling is not necessary in routine.