Anatomic correlates of memory from intracarotid amobarbital injections with technetium Tc 99m hexamethylpropyleneamine oxime SPECT
J. Hart Jr, P. J. Lewis, R. P. Lesser, R. S. Fisher, L. H. Monsein, P. Schwerdt, K. Bandeen-Roche and B. Gordon
OBJECTIVE--To better identify regions of the brain affected by intracarotid
amobarbital injections and to more precisely predict whether resections of
specific brain regions will cause postoperative memory deficits. DESIGN--We
modified the standard intracarotid amobarbital procedure by adding a
radioactive tracer to the amobarbital injection, thereby providing better
correlation between behavior and deactivated brain region.
SETTING--Tertiary-care hospital center with a dedicated program for medical
and surgical treatment of epilepsy. PATIENTS--We studied 39 patients with
medically intractable epilepsy drawn from a regional referral base.
INTERVENTION--Intracarotid injection of 125 mg of sodium amobarbital with
37 MBq of technetium Tc 99m hexamethylpropyleneamine oxime (HMPAO),
followed by language and memory testing. MAIN OUTCOME MEASURES--The
distribution of amobarbital as measured by single photon emission computed
tomographic imaging of HMPAO and patient performance on memory tasks.
RESULTS--Medial temporal regions were irrigated by the amobarbital in only
28% of the injections. Overall, findings suggest that medial temporal and
lateral neotemporal cortex play a role in memory. CONCLUSIONS--The regions
involved in memory function vary by individual, as does the distribution of
amobarbital. Thus, the most accurate method of determining correlation of
brain region with memory function during intracarotid amobarbital injection
involves the use of a tracer such as HMPAO.
