Is there any role for gadopentetate dimeglumine administration when searching for mesial temporal sclerosis in patients with seizures?

MR Imaging of Epilepsy: Strategies for Successful Interpretation

MR imaging plays a pivotal role in the evaluation of patients with epilepsy. With its high spatial resolution, excellent inherent soft tissue contrast, multiplanar imaging capability, and lack of ionizing radiation, MR imaging has emerged as a versatile diagnostic tool in the evaluation of patients with epilepsy. MR imaging not only identifies specific epileptogenic substrates but also determines specific treatment and predicts prognosis. Employing appropriate imaging protocols and reviewing the images in a systematic manner helps in the identification of subtle epileptogenic structural abnormalities. With future improvements in software, hardware, and post-processing methods, MR imaging should be able to throw more light on epileptogenesis and help physicians to better understand its structural basis.

MR imaging of epilepsy: strategies for successful interpretation

MR imaging plays a pivotal role in the evaluation of patients with epilepsy. With its high spatial resolution, excellent inherent soft tissue contrast,multiplanar imaging capability, and lack of ionizing radiation, MR imaging has emerged as a versatile diagnostic tool in the evaluation of patients with epilepsy. MR imaging not only identifies specific epileptogenic substrates but also determines specific treatment and predicts prognosis. Employing appropriate imaging protocols and reviewing the images ina systematic manner helps in the identification of subtle epileptogenic structural abnormalities. With future improvements in software, hardware, and post-processing methods, MR imaging should be able to throw more light on epileptogenesis and help physicians to better understand its structural basis.

Perfusion-weighted imaging of interictal hypoperfusion in temporal lobe epilepsy using FAIR-HASTE: comparison with H(2)(15)O PET measurements

To detect perfusion abnormalities in areas of high magnetic susceptibility in the brain, an arterial spin-labeling MRI technique utilizing flow-sensitive alternating inversion recovery (FAIR) and half-Fourier single shot turbo spin-echo (HASTE) for spin preparation and image acquisition, respectively, was developed. It was initially tested in a functional study involving visual stimulation, and was able to detect significant activation with an increase (approximately 70%) in relative cerebral blood flow. Subsequently, it was applied in a clinical situation in eight patients with temporal lobe epilepsy (TLE). The perfusion-weighted images obtained showed no susceptibility artifacts even in the region of the inferior temporal lobe and were able to detect interictal hypoperfusion in TLE. The results were compared with those derived from H(2)(15)O PET perfusion imaging in each patient. A statistically significant correlation (r = 0.75, P < 0.05) was found between results acquired from these two modalities. Magn Reson Med 45:431-435, 2001.

MR measurement of regional relative cerebral blood volume in epilepsy

The purpose of this study was to evaluate the utility of magnetic resonance (MR) relative cerebral blood volume (rCBV) maps for studying regional hemodynamic changes in interictal and ictal epilepsy patients. Ten epilepsy patients were examined on a 1.5 T MR system. Nine patients were investigated interictally and one patient ictally. In the nine interictal patients, the dynamic plane was defined coronally through the hippocampus symmetrically. For the ictal patient, an axial dynamic plane was defined and the patient was scanned during seizure. Positron emission tomography (PET) studies were performed in 8 of the 10 patients. Lower rCBV of the left hippocampus was predicted by rCBV maps in seven of the nine interictal patients. The mean ratios of rCBV were 1.96 for left hippocampus/white matter and 2.49 for right hippocampus/white matter. The difference between these two ratios is statistically significant (P = 0.01, t-test). In two of the nine interictal temporal lobe epilepsy patients, lower rCBV areas were observed in the right hippocampus. In the ictal patient, the regional rCBV map demonstrated increased blood volume in the lesions. In eight of eight patients who underwent PET studies, MR rCBV findings were consistent with PET findings. The results show that regional hemodynamic changes in epilepsy can be evaluated with dynamic contrast-enhanced MR imaging. MR rCBV maps are sensitive to characterize seizure foci both ictally and interictally.