Subtraction Peri-Ictal SPECT in Schizencephaly
Abstract number :
1.221
Submission category :
Year :
2001
Submission ID :
3060
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
G.D. Cascino, MD, Neurology, Mayo Clinic, Rochester, MN; J.R. Buchhalter, MD, Neurology, Mayo Clinic, Rochester, MN; E.L. So, MD, Neurology, Mayo Clinic, Rochester, MN; B.P. Mullan, MD, Nuclear Medicine, Mayo Clinic, Rochester, MN
RATIONALE: To determine the clinical utility of subtraction ictal SPECT co-registered with MRI (SISCOM) in patients with schizencephaly. Patients with this malformation of cortical development may have an intractable seizure disorder and be considered for surgical treatment. The structural MRI findings in patients with unilateral schizencephaly may allow lateralization, but not localization, of the epileptogenic zone. SISCOM has been shown to be a reliable indicator of the site of seizure onset in patients with partial epilepsy (O[ssquote]Brien TJ et al., Neurology 2000;55:1668-1677).
METHODS: SISCOM images in 4 consecutive patients with schizencephaly at Mayo Clinic, Rochester, MN were reviewed. All patients had medically refractory partial seizure disorders. The SPECT injection and imaging methods were performed as previously described (O[ssquote]Brien TJ, Nucl Med Commun 1998;31:15-22). All patients underwent long-term ictal video-EEG monitoring and an MRI head seizure protocol.
RESULTS: The mean age was 25 years (range, 16-33). MRI revealed a fused or closed lip malformation in 3 patients. The schizencephaly was unilateral and most prominent in the peri-rolandic region in all 4 patients. Two of the 4 patients had a SISCOM-identified localized region of cerebral hyperperfusion that was intimately related to the malformation of cortical development. Two patients had nonlocalized SISCOM studies. One of the 2 patients had multiple areas of hyperperfusion that correctly lateralized the malformation. This patient proceeded with chronic intracranial EEG monitoring using a subdural grid plate of electrodes and had multifocal seizures. None of the 4 patients have undergone surgical treatment.
CONCLUSIONS: Subtraction peri-ictal SPECT studies may reveal localized or lateralized alterations in cerebral blood flow in patients with schizencephaly. SISCOM may alter the preoperative evaluation and provide a [dsquote]target[dsquote] for intracranial EEG recordings. The diagnostic yield of SISCOM in correctly identifying the ictal onset zone in these patients remains to be determined.
Support: Mayo Foundation.