Relative to the contralateral side, there is a subtle hypometabolism of the anterior/lateral left temporal lobe, suspicious for seizure focus. This is more obvious when viewed with surface metabolism/hypometabolism maps:

The patient subsequently underwent another imaging procedure, depicted below. What is the name of this test and what is the purpose?

This patient underwent a cerebral angiogram and Wada test. This is a neurologic assessment (speech, short term memory, etc.) of each hemisphere of the brain, done by asking the patient a series of questions while one hemisphere is temporarily anesthetized by intra-arterial injection of sodium amytal. It is perfomed to evaluate suitability of brain resection.

In this patient, speech/language function and recognition memory was predominantly mediated by the left hemisphere.

The patient went on to have intracranial grid placement for further confirmation of seizure focus. Based upon the information from the above imaging tests, she had resection of the anterior/lateral left temporal lobe. The hippocampus and mesial temporal structures were spared as much as possible, to minimize effect on memory.

Subtle cortical thickening can be seen in this region on preoperative MRI (left). Pathology demonstrated focal cortical dysplasia with dymorphic neurons and ballooned cells.

This case illustrates the evaluation prior to surgical resection for intractable seizures.

Ictal SPECT (using a perfusion agent such as HMPAO) is cited as the most useful study to identify a seizure focus, with up to 90% sensitivity in the temporal lobe. This method requires an epilepsy monitoring unit and other technical demands.

Interictal studies have sensitivity in the range of 70%, with FDG PET reported as slightly more sensitive than interictal SPECT.

Sarikaya I. Am J Nucl Med Mol Imaging 2015;5:416-430.
Ziessman HA, O’Malley JP, Thrall JH, eds. Nuclear Medicine, the Requisites, 4th ed. Philadelphia: Elsevier, 2014.