<s>[INST] context: The image in the question is Coronal T2W brain MRI showing bilateral symmetrical hyperintensity along coicospinal tract (white arrows) forming a 'wine glass appearance'.MRI can be used in revealing lesions in coicospinal tracts in ALS. The earliest MR manifestation is hyperintensity on T2WI in the coicospinal tracts, seen earliest in the internal capsule, as the fibers are most concentrated here. Thereafter, the entire tract from motor strip to the spinal cord is affected with increased T2 signal and loss of volume. Amyotrophic lateral sclerosis It is characterized by progressive muscle weakness, limb and truncal atrophy and bulbar signs and symptoms. Mean age at diagnosis is 57 years. Disease progression is relentless; half the patients are dead within 3 years and 90% have died by 6 years following symptom onset.As it is a progressive disease, so there is no known cure or way of reversing its effect. The other name of this disease is Lou Gehrig's disease and Charcoat's disease. Non-tau inclusions and degeneration in spinal motor neurons and pyramidal tracts (coicospinal tracts) usually produce signal changes on T2WI. T2WI shows high signal areas along the large myelinated pyramidal tract fibers in the posterior limb of the internal capsule and cerebral peduncles in about 25% cases.Thereafter, the entire tract from motor strip to the spinal cord is affected with increased T2 signal and loss of volume. MRI imaging of the brain and spinal cord, especially with IV gadolinium, also helps to diagnose multiple sclerosis (MS). The brain MRI is abnormal in 95% to 99% of cases of Relapsing/Remitting MS. Typical MS lesions are bright lesions on T2-weighted imaging, especially in the corpus callosum and periventricular regions. These lesions are usually linear or ovoid and at right angles to the ventricular surface, which are named Dawson fingers after the Scottish pathologist who described it. The most frequent neurological manifestation of vitamin B12 deficiency is the subacute combined degeneration (SACD) of the spinal cord and polyneuropathy, rarely dementia and damage of the optic nerve occur. Numbness of the limbs and trunk is an early symptom; weakness, clumsiness and spasticity, abnormal reflexes, gait ataxia develop later. MRI reveals hyperintensities involving dorsal columns of spinal cord in cervical and upper dorsal region. Timely parenteral Vit B12 can result in complete resolution clinically as well as radiologically. Spinal muscular atrophy (SMA) is the most commonly inherited neurodegenerative disease that leads to infant moality worldwide. Itis the leading genetic cause of infant death. On MRI,low intensity areas are seen scattered through the muscle. [/INST] question: A middle-aged vegetarian man presents with progressive atrophy and weakness of hands and forearms. On examination he is found to have slight spasticity of legs, and generalized hyperreflexia. MRI study if the brain was obtained and increased signals were noted in thecoicospinal tracts on T2 weighted MRI (shown below). The most likely diagnosis is | options: A: Multiple sclerosis B: Amyotrophic lateral sclerosis C: Subacute combined degeneration D: Progressive spinal muscular atrophy | answer: B </s>