Pseudoresponse can also be problematic, with an apparent decrease in contrast enhancement in a tumor due to changes in vascular permeability as opposed to true tumor response also resulting in a complicated interpretation [39]. MR spectroscopy and MR perfusion can be effective adjunct imaging examinations to complement conventional MRI [38]. HMPAO SPECT or SPECT/CT Brain Ictal and Interictal There is no relevant literature regarding the use of SPECT or SPECT/CT in the evaluation of known seizure disorder with history of tumor unless in the setting of presurgical planning. Variant 6: Known seizure disorder. Surgical candidate or surgical planning. CT Head Evaluation of seizures was greatly advanced by the clinical introduction of CT in the early 1970s [40,41] because of its cross-sectional capabilities that were not possible with radiographs. However, CT is outperformed by MRI in Seizures and Epilepsy having less contrast resolution between gray and white matter differentiation [16], and overall CT is less sensitive to detecting lesions compared with MRI [41,42]. CT is useful in the assessment of calcification pathologies, such as tuberous sclerosis and oligodendrogliomas [23]. CT can be used for stereotactical surgical planning, and high- resolution CT can be used to assess the position of subdural grid or depth electrodes [23], which can be done without IV contrast administration. Noncontrast CT and MRI have been advocated equally for accurate electrode localization [43]. FDG-PET/CT Brain Clinical FDG-PET/CT provides a measure of glucose uptake and thus a measure of metabolism and has been shown to be highly sensitive in the presurgical localization of epileptogenic foci [8]. A seizure focus will typically manifest as a focus of hypometabolism on interictal (between episodes of seizure activity) PET examinations. One study demonstrated that presurgical ipsilateral PET hypometabolism showed predictive value of 86% for good surgical outcomes [44].
Seizures and Epilepsy. Pseudoresponse can also be problematic, with an apparent decrease in contrast enhancement in a tumor due to changes in vascular permeability as opposed to true tumor response also resulting in a complicated interpretation [39]. MR spectroscopy and MR perfusion can be effective adjunct imaging examinations to complement conventional MRI [38]. HMPAO SPECT or SPECT/CT Brain Ictal and Interictal There is no relevant literature regarding the use of SPECT or SPECT/CT in the evaluation of known seizure disorder with history of tumor unless in the setting of presurgical planning. Variant 6: Known seizure disorder. Surgical candidate or surgical planning. CT Head Evaluation of seizures was greatly advanced by the clinical introduction of CT in the early 1970s [40,41] because of its cross-sectional capabilities that were not possible with radiographs. However, CT is outperformed by MRI in Seizures and Epilepsy having less contrast resolution between gray and white matter differentiation [16], and overall CT is less sensitive to detecting lesions compared with MRI [41,42]. CT is useful in the assessment of calcification pathologies, such as tuberous sclerosis and oligodendrogliomas [23]. CT can be used for stereotactical surgical planning, and high- resolution CT can be used to assess the position of subdural grid or depth electrodes [23], which can be done without IV contrast administration. Noncontrast CT and MRI have been advocated equally for accurate electrode localization [43]. FDG-PET/CT Brain Clinical FDG-PET/CT provides a measure of glucose uptake and thus a measure of metabolism and has been shown to be highly sensitive in the presurgical localization of epileptogenic foci [8]. A seizure focus will typically manifest as a focus of hypometabolism on interictal (between episodes of seizure activity) PET examinations. One study demonstrated that presurgical ipsilateral PET hypometabolism showed predictive value of 86% for good surgical outcomes [44].