Article courtesy of Sime Darby Healthcare

24 May 2009 - Jeremy from Sarawak was a week old when he was diagnosed with epilepsy. His epileptic seizures worsened in a matter of weeks. At one point, he had as many as 60 fits a day, even with four anti-convulsant medications. His sleep patterns were disturbed, and he had problems swallowing his milk, sometimes requiring tube-feeding.

He was also slow in his mental development and had weak upper limbs. This went on until he was one and a half years old when he was referred to a private hospital.

3T MRI was used in his neuroimaging together with EEG (electro-encephalogram). He was then referred for epilepsy surgery under a neurosurgeon specially trained in the sub-specialty. After the surgery, he was immediately seizure-free, and since then his condition has improved significantly.

He can now swallow his food better, is more active, and is progressing well in his growth.

Over the past decade, the imaging of epilepsy has changed substantially. With the advent of high resolution MRI (Magnetic Resonance Imaging) such as the 3.0Tesla (3T) MRI System with proper epilepsy protocol, diagnosis of epilepsy has significantly increased.

Earlier, CT (computerised tomography) scans only revealed pathologic substrates for epilepsy to a certain extent. Early low-field strength MRI increased the diagnostic yield but could only identify obvious pathologies such as neoplasms, encephalomalacia and vascular malformations.

New cutting-edge neuroimaging techniques such as 3T MRI have significantly improved the ability to identify focal and diffuse pathologies that can cause epilepsy. 3T MRI, with its application in clinical epilepsy, has increased the understanding of structure as it relates to various epileptic syndromes and has become the imaging modality of choice in the investigation of patients with epilepsy.

3T MRI has a dramatic clinical impact in the management of epilepsy by assisting with classification, prognosis for remission, long term intractability prediction to anti-epileptic medications, and also in identifying potential surgical candidates.

3T MRI may increase the ability to detect lesions and define their character. This is due to the thinner slices and higher resolution of images, which display anatomy and pathology more accurately.

Dr Ben Selladurai, a consultant neurosurgeon who specialises in epilepsy surgery, related the case of a 14-year-old male patient who had been suffering epileptic fits for six years, which could not be controlled by medications or medicines for epilepsy.

“The 3T MRI scan showed a small tumour in the speech area, the area of the brain concerned with the expression of speech. Surgery had a 60% to 70% chance of curing his epilepsy, but there was a risk of disturbing his speech function during the surgical procedure.

“The only sure way of avoiding speech defects arising from the surgery was to perform the surgery of removal of the tumour while testing speech function at the same time. This procedure is called an awake craniotomy, where the patient is awake during the removal of the tumour in the brain for his speech to be tested.”

When focal seizures become medically refractory, 3T MRI may assist in selecting suitable surgical candidates, and in guiding the surgical resection. When an abnormality is detected, its location is usually interpreted in the context of the available EEG and video-EEG data. Certain patients may be considered for surgery at this point, if the imaging and EEG data are agreeable.

3T MRI can identify epileptogenic focus. Since cortical and subcortical epileptogenic lesions such as cortical dysplasia are rather subtle and difficult to characterise and localise with conventional imaging, 3T MRI is now considered routine and crucial in the evaluation of medically refractory focal seizures.

Alternatively, dual pathology may contribute to the seizure whereas only one of the abnormalities is apparent on the standard MRI. Comparatively, 3T MRI has higher resolution in detecting these subtle lesions.

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