Nevertheless, it can be useful as a complementary modality in assessment of location of seizures in preoperative brain mapping as well as identification of eloquent cortex to determine safe resection margins [51]. MRI Functional (fMRI) Head The utility of fMRI has been well described in the literature in the setting of presurgical evaluation of patients with epilepsy [44,52] and perhaps even more so in the setting of MRI-negative epilepsy [18]. For patients with drug- resistant focal epilepsy, functional neuroimaging techniques, such as FDG-PET, ictal SPECT, or fMRI, may assist in surgical planning, especially in patients with MRI-negative epilepsy, whose prognosis for a seizure-free outcome after surgery is worse than for patients with an epileptogenic lesion on structural MRI. fMRI demonstrated 89% concordance in language lateralization with an intracarotid amobarbital procedure (IAP) with right TLE and 85% for left TLE [53]. The same study also demonstrated 83% concordance with IAP in language lateralization extra- TLE [53], and as such, fMRI can be considered as a replacement for IAP for language lateralization [52]. One study demonstrated that strong left frontal activation was predictive of postresection decline [53], and thus fMRI can be considered for predicting postsurgical language deficits in presurgical evaluation for possible temporal lobectomy [52]. fMRI can be an option to lateralize memory functions with good correlation on one study (r = 0.31; P = . 007) between hippocampal fMRI laterality index and IAP memory laterality index [54]; however, conflicting data showing no correlation were also found in the literature [55]. fMRI using model paradigms is a promising method to noninvasively predict memory decline [56]. MRI Head MRI demonstrates excellent gray-white matter differentiation and multiplanar imaging capability, characteristics that contribute to greater sensitivity and accuracy of MRI compared with CT [8,31].
Seizures and Epilepsy. Nevertheless, it can be useful as a complementary modality in assessment of location of seizures in preoperative brain mapping as well as identification of eloquent cortex to determine safe resection margins [51]. MRI Functional (fMRI) Head The utility of fMRI has been well described in the literature in the setting of presurgical evaluation of patients with epilepsy [44,52] and perhaps even more so in the setting of MRI-negative epilepsy [18]. For patients with drug- resistant focal epilepsy, functional neuroimaging techniques, such as FDG-PET, ictal SPECT, or fMRI, may assist in surgical planning, especially in patients with MRI-negative epilepsy, whose prognosis for a seizure-free outcome after surgery is worse than for patients with an epileptogenic lesion on structural MRI. fMRI demonstrated 89% concordance in language lateralization with an intracarotid amobarbital procedure (IAP) with right TLE and 85% for left TLE [53]. The same study also demonstrated 83% concordance with IAP in language lateralization extra- TLE [53], and as such, fMRI can be considered as a replacement for IAP for language lateralization [52]. One study demonstrated that strong left frontal activation was predictive of postresection decline [53], and thus fMRI can be considered for predicting postsurgical language deficits in presurgical evaluation for possible temporal lobectomy [52]. fMRI can be an option to lateralize memory functions with good correlation on one study (r = 0.31; P = . 007) between hippocampal fMRI laterality index and IAP memory laterality index [54]; however, conflicting data showing no correlation were also found in the literature [55]. fMRI using model paradigms is a promising method to noninvasively predict memory decline [56]. MRI Head MRI demonstrates excellent gray-white matter differentiation and multiplanar imaging capability, characteristics that contribute to greater sensitivity and accuracy of MRI compared with CT [8,31].