Potential of nigrosome imaging for earlier diagnosis of Parkinson’s
New study results may contribute to earlier diagnosis of Parkinson’s disease
Neurophysicists led by Malte Brammerloh of the Max Planck Institute for Human Cognitive and Brain Sciences have discovered that the identification of a magnetic resonance imaging signature for Parkinson’s diagnosis as a specific anatomical region in the brain is widespread but incorrect. A better understanding of the MRI contrast of the anatomical region called “nigrosomes 1” has cleared up the misunderstanding and may even contribute to the earlier diagnosis of Parkinson’s.
“That MRI sign, the so-called swallowtail sign, includes part of the anatomical region ‘nigrosomes 1’, but looks very different,” explains the first author of the study. “This is relevant to the clinical field because the identification ‘swallow tail sign corresponds to nigrosome 1’ has become the doctrine and needs to be revised.”
In Parkinson’s disease, dopamine-producing nerve cells in the substantia nigra in the midbrain die, leading to movement disorders such as sluggishness, stiff muscles and tremors in sufferers. The nerve cells in nigrosome 1 within the substantia nigra are particularly severely and early affected. With high-resolution MRI imaging, it is possible to image the dovetail sign, which is located in the posterior third of the substantia nigra and according to conventional wisdom corresponds to nigrosome 1.
In healthy people, the MRI image shows a high-signal, elongated structure surrounded by low-signal areas at the front and sides. This special shape is reminiscent of a swallow’s tail, which is why it is also called the swallow’s tail sign. According to the current interpretation of the sign, the death of the neurons in nigrosome 1 in people with Parkinson’s disease results in the dovetail sign becoming unrecognizable. If this is the case, there is a high probability of Parkinson’s disease.
Malte Brammerloh and his colleagues have now combined 3D microscopic examinations of postmortem human brains with MRI technology to show that nigrosome 1 and the radiological swallowtail sign only partially overlap and are in fact very different. The researchers therefore argue that the swallowtail sign should not be equated with the nigrosome 1 region. This allows a reinterpretation of the diagnostic swallowtail sign and at the same time opens new avenues for specific nigrosome imaging. Brammerloh: “We believe that with this new knowledge we can better understand how anatomy and MRI contrasts are related and how new MRI markers can be developed for the early diagnosis of Parkinson’s disease.”