MS Dissemination.

According to the Consortium of MS Centers Task Force, an international group of neurologists and radiologists, standardized brain and spinal cord MR imaging for the diagnosis and follow-up of MS should include the following ^[6] :

• A brain MR imaging with gadolinium is recommended for the diagnosis of MS.
• A spinal cord MR imaging is recommended if the brain MR imaging is nondiagnostic or if the presenting symptoms are at the level of the spinal cord.
• A follow-up brain MR imaging with gadolinium is recommended to demonstrate dissemination in time and ongoing clinically silent disease activity while on treatment, to evaluate unexpected clinical worsening, to re-assess the original diagnosis, and as a new baseline before starting or modifying therapy.
• A routine brain MR imaging should be considered every 6 months to 2 years for all patients with relapsing MS.
• The brain MR imaging protocol includes 3D T1-weighted, 3D T2-FLAIR, 3D T2-weighted, post-single-dose gadolinium-enhanced T1-weighted sequences, and a DWI sequence.
• The progressive multifocal leukoencephalopathy surveillance protocol includes FLAIR and DWI sequences only.
• The spinal cord MR imaging protocol includes sagittal T1-weighted and proton attenuation, STIR or phase-sensitive inversion recovery, axial T2- or T2*-weighted imaging through suspicious lesions, and, in some cases, postcontrast gadolinium-enhanced T1-weighted imaging.
• Dissemination In Space: One or two hyper intense lesion affecting two or more location.
• Dissemination In time: New lesion comparing to previous study or asymptomatic enhancing lesion + non enhancing lesion.
•  Lesions may be observed anywhere in the CNS white matter, including the supratentorium, infratentorium, and spinal cord; however, more typical locations for MS lesions include the periventricular white matter, brainstem, cerebellum, and spinal cord. Ovoid lesions perpendicular to the ventricles are common in MS and occasionally are called Dawson bars or fingers, which occur along the path of the deep medullary veins. Perhaps the most specific lesions in MS are noted in the corpus callosum at the interface with the septum pellucidum. 

Axial diffusion-weighted MRI in a patient with multiple sclerosis shows several hyperintense lesions, a feature of inflammatory disease activity.

Reference