Letter to Editor

Figure 2: Fluid-attenuated inversion recovery (FLAIR)- sagittal sequence MR imaging of the brain showing a focal hyperintense lesion in midbrain tegmentum Figure 1: Proton density (PD)- coronal sequence MR imaging of brain showing a focal hyperintense lesion in midbrain tegmentum on the right side, in the region of trochlear nucleus nervous system infections including neurosyphilis, Arnold-Chiari malformation with associated syringobulbia, Wernicke’s encephalopathy, and hepatic encephalopathy.5 In our patient all the other possibilities other than demyelinating pathology were excluded. She did not have any prodromal illness or vac-cination before the onset of the illness and no other white matter MRI lesions. We feel that our patient is probably a case of primary demyelinating disease, possible MS. The newly revised MRI diagnostic criteria for MS allow the diagnosis to be made after one attack, if stringent MRI criteria are met. It has been emphasized that in patients with first attack of de-myelinating disease, a diagnosis should be withheld unless new symptoms and signs or imaging abnormalities appear, more than 3 months after the onset of clinical symptoms.6 Clinical examination fails to detect INO in 71 % and 25 % of the cases with mild and moderate INO respectively, and de-tection is improved by quantitative infrared oculography.3 MRI is the imaging modality of choice to detect the lesions of MLF.7 In MS patients with INO, hyperintense lesions in MLF have been demonstrated in all patients on PD sequence, in 88 % on T2-weighted imaging and in 44 % on FLAIR sequences.4 In our patients the lesion in the MLF was detected only on PD coronal and FLAIR. Thus our recommendation in patients is to acquire PD sequence in addition to the other sequences in a patient with suspected INO