Tractography finds unseen lesions in a case of cortical dysplasia!

Conventional MRI of a 30 years old male patients with intractable right sided partial seizures showed the presence of left superior frontal cortical dysplasia

Tractography showed the unorganised white matter bundles in the left frontal lobe

However it unravelled more extensive changes of white matter disorganisation invvelving almost whole of the left hemisphere.

Tractography also revealed an area of absence of fibres in the left lower thalamus, subthalamic paraventricular region probable related to an underlying lesion there-? heterotopia

Fig 1. color coded tracts overlayed upon MPRAGE image at centrum semiovale level (side reversed): shows 'more' number of fibres in the left side. The tracts are unorganised as evident by the haphazard intemingling of the different colors. The bulge towards the midline anteriorly is the area seen on conventional MRI. Note that the above-said area has maximum disorganisation(lot of mixture of purple, red, blue,green and yellow)

The following images (Side reversed) shows the focal 'void' in the tract bundles in the left inferior thalamus paraventricular region

The color coded DTI map (side unreversed)shows the same finding. Note that the area of 'void' in the tractography images seen above shows a collection bunch of diferent colors ( mainly purple) indicating a loss of coherent anisotropy

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Chronic Multiple Sclerosis

A case of chronic RRMS shows diffuse atrophy with periventricular white matter hyperintensity

MR spectroscopy from left parieto-occipital white matter, which has the maximum hyperintensity, shows, as expected raised choline, decreased NAA and presence of lactate, i.e changes of demyelination and tissue loss

MRS from right parieto-occipital white matter also shows decreased NAA/Cho ratio and raised lactate


However, noteworthy is the presence of similar changes on spectroscopy in the normal appearing areas too

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Tractography in right frontal glioma

Preoperative tractography done in a large frontal lobe anaplastic astrocytoma.

Look at the 'absence' of the white matter tracts.

Some tracts have been displaced and stretched but a significant part of the white matter has disappeared altogether.

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