[Researches for diagnostic neuroradiology focusing on signals and shapes]

MRI is one of essential tools for neurological diagnosis and useful for assessing contrast differences between lesions and normal tissues and for assessing morphological features of lesions. Here, I introduce published neuroradiological researches conducted in my hospital, especially focusing on features of "signals" and "shapes" of lesions. First, as regards "signals", putaminal T(1)-hyperintensity is helpful for diagnosing multiple system atrophy, and it is more useful for discriminating multiple system atrophy from Parkinson disease and progressive supranuclear palsy than putaminal T(2)-hyperintensity rim or putaminal T(2)-hypointensity. Linear T(2)-hyperintensity along the medial margin of the globus pallidus is helpful for diagnosis Machado-Joseph disease. Second, as regards "shapes", posterolateral putaminal linearization is a useful finding indicating putaminal atrophy which is a main feature of multiple system atrophy. Flattened facial colliculus/fourth ventricular floor is helpful for differentiating Machado-Joseph disease from dentatorublopallidoluysian atrophy and SCA6. A contrast enhancement pattern called "cloud-like enhancement" is specific for neuromyelitis optica comparing with multiple sclerosis. In conclusion, all of these MRI features are easy to recognize and useful for diagnosing patients in daily clinical settings. Careful but simple observation of lesions focusing on "signals" or "shapes" may lead to develop new MRI findings which improve our diagnostic abilities.