Neurology: What are the unique manifestations of MRI for hereditary frontotemporal dementia?

The key to successfully determining a new treatment for frontotemporal lobe degeneration (FTLD) is whether it can identify useful markers that reflect the specific biological process of this heterogeneous clinical syndrome
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Cases caused by genetic mutations account for 30% of FTLD manifestations, providing an ideal model for studying these processes, because the underlying pathology can be inferred (even if there is no postmortem confirmation), which is conducive to the design of treatment trials for specific molecular mechanisms

Neuroimaging has proven that it provides in vivo, non-invasive neurodegeneration indicators in the FTLD phenotype

The unique atrophy pattern on structural MRI helps to establish the correct diagnosis of frontotemporal dementia (bvFTD) and primary progressive aphasia (PPA) , helps to distinguish FTLD patients from patients with different diseases, and even Provide hints for the underlying genetic and pathological basis of each patient
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diagnosis

Recently, studies have been conducted on the role of pathological burden in the gray matter (GM) structure outside the cerebral cortex, showing that the manifestations of hereditary FTLD (gFTLD) include motor neuron disease (MND), deep GM and cerebellar structure There is a unique degeneration
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However, most previous studies have focused on purely cognitive phenotypes, and extensive descriptions of subcortical and cerebellar injuries in each genetic form of the FTD/MND spectrum (including C9orf72-related diseases) are still in progress
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The extensive description of subcortical and cerebellar injury in each inherited form of the FTD/MND lineage (including C9orf72-related diseases) is still in progress
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In this way, Edoardo Gioele Spinelli and others of IRCCS San Raffaele Scientific Institute, Italy, explored the neuroanatomical structure-related factors of genetic heterogeneity in a patient group affected by a wide range of FTLD diseases (including MND)
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More specifically, a systematic method was used to assess the atrophy patterns of cortical, subcortical and cerebellar structures, and the latest MRI volume measurement technology was used to determine neuroimaging indicators related to specific genetic changes
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They included a total of 66 patients with FTLD-related mutations, including 44 pure motor neuron disease (MND) and 22 frontotemporal dementia (FTD).
They also included 61 patients with genetic FTLD in terms of age, gender, and disease severity.
(GFTLD) matched sporadic FTLD (sFTLD) patients, and 52 healthy controls
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A whole brain voxel-based morphometric (VBM) analysis was performed to obtain the gene volume of subcortical and cerebellar structures

They found that compared with the control group, the GM atrophy of hereditary FTD was greater and more diffuse, followed by sporadic FTD and hereditary MND cases, while patients with sporadic MND (sMND) showed focal motor cortical atrophy
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Compared with the control group, the GM atrophy of hereditary FTD was greater and more diffuse, followed by sporadic FTD and hereditary MND cases, while patients with sporadic MND (sMND) showed focal motor cortical atrophy
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Patients with C9orf72 and GRN mutations showed the most extensive loss of cortical volume, in contrast to the GM sparseness of SOD1 and TARDBP
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On the whole, patients with gFTLD have greater atrophy of the top cortex and thalamus compared with sFTLD
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In volume analysis, gFTLD patients showed volume loss in the caudate nucleus and thalamus compared with sFTLD, especially in the comparison of C9-MND and sMND cases

In the cerebellum, the atrophy of the right lobule VIIb of gFTLD patients is greater than that of sFTLD
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The thalamus volume of C9orf72 mutant gFTLD patients is inversely related to the score of the Frontal Lobe Behavior Scale

Regardless of the clinical manifestations in the FTLD spectrum, the measurement of deep GM and cerebellar structure involvement may be a useful marker for gFTLD, especially C9orf72-related diseases
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Original source:
Spinelli EG, Ghirelli A, Basaia S, et al.

Structural MRI Signatures in Genetic Presentations of the Frontotemporal Dementia-Motor Neuron Disease Spectrum.
 Neurology.

Structural MRI Signatures in Genetic Presentations of the Frontotemporal Dementia-Motor Neuron Disease Spectrum.
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