Functional magnetic resonance imaging of the primary motor cortex in humans: response to increased functional demands.

Functional magnetic resonance imaging (fMRI) studies have been performed on 20 right handed volunteers at 1.5 Tesla using echo planar imaging (EPI) protocol. Index finger tapping invoked localized activation in the primary motor area. Consistent and highly reproducible activation in the primary motor area was observed in six different sessions of a volunteer over a period of one month. Increased tapping rate resulted in increase in the blood oxygenation level dependent (BOLD) signal intensity as well as the volume/area of activation (pixels) in the contralateral primary motor area up to tapping rate of 120 taps/min (2 Hz), beyond which it saturates. Activation in supplementary motor area was also observed. The obtained results are correlated to increased functional demands.

Co-existence of dual intracranial pathology clinical relevance of proton MRS.

The co-existence of neuro-cysticercosis (NCC) and intracranial neoplasm in an individual is a rare entity. Atypical presentation of cerebral cysticercosis may mimic glioma, metastasis, cerebral abscess or vice versa. The dual existence of these two lesions have led to several postulates which may have clinical impact in due course of time i.e. NCC as an oncogenetic factor for glioma or similarity of antigen found in glioma and NCC etc. An adequate management of such cases poses a challenge to both imageologists as well as clinicians. Thus, a proper diagnostic evaluation is essential for successful management of such cases. MR spectroscopy (MRS), although still a clinical research tool, may be extremely useful for exclusion or confirmation of neoplastic lesions in such a clinical scenario. The findings of MRS in collaboration with imaging parameters may increase the diagnostic yield of a MR investigation. The authors encountered five cases of dual intracranial pathologies i.e. neurocysticercosis and glioma. MR spectroscopy was useful to arrive at a definitive diagnosis in such a situation.