1. NEUROIMAGING FINDINGS OF RARE NEURODEGENERATIVE DISEASES RELATED TO DEMENTIA SYMPTOMS
INTRODUCTION:
Neurodegenerative diseases are diversified group of disorders clinically related to variety of neurological alterations and decreased cognition (1,2). The most common neurodegenerative disorder is Alzheimer disease but some of rare neurodegenerative disorders apart from gradual neurologic disfunction proceed with dementia symptomps as well, i.a.:
- progressive supranuclear palsy (PSP) is a tauopathy with parkinsonian symptoms with midbrain atrophy (Fig.1.);
- multiple system atrophy (MSA) is a synucleinopathy divided into 2 forms: MSA-C with predominance of cerebellar symptoms and cerebellar atrophy (Fig.2.) and MSA-P with predominant parkinsonian features and involvment of putamen (Fig.3.);
- corticobasal degeneration (CBD) is a tauopathy with asymmetric parkinsionan symptoms and asymmetric brain atrophy (Fig.4.);
- Creutzfeldt-Jacob disease (CJD) is a prion disease characterised by rapidly progressive brain atrophy, dementia, myoclonus, and death, (Fig.5.);
- Huntington disease (HD) is an autosomal dominant disease with progressive rigidity, choreoathetosis, psychosis and atrophy of caudate nuclei (Fig.6.).
Magnetic resonance imaging (MRI) sequences, in particular T2-weighted imaging, FLAIR, DWI (diffusion weighted imaging) and SWI (susceptibility weighted imaging) allow to assess typical brain changes in these disorders. Radiologist may be the first specialist who can suggest these diagnoses.
AIM: The aim of this study is to present characteristic neuroimaging findings of rare neurodegenerative diseases causing cognitive impairment.
NEUROIMAGING FINDINGS OF RARE NEURODEGENERATIVE DISORDERS:
Fig. 1. PSP is characterised by midbrain atrophy which results in hummingbird sign on sagittal T2W image (A, circle) and Mickey Mouse or morning glory appearance on axial T2W images (B, circle).
Fig. 4. For CBD asymmetric atrophy of the cortex and basal ganglia is typical. Axial T2W (A), axial FLAIR (B) and sagittal T2W images show asymmetric cortIcal atrophy of peri-Rolandic gyri in the left hemisphere (red arrows)
Fig. 2. MSA-C manifests as predominant cerebellar atrophy (with enlargement of cerebellar fissures) and a hot cross bun sign in pons, what is seen on axial T2-weighted images (red circle)
Fig. 5. CJD appears as hyperintensities on T2WI/FLAIR (not shown) with early restriction of diffusion on DWI within basal ganglia (A, red and blue arrows), thalamus (A, hockey stick/pulvinar sign - green arrow) and cortex (B, circle).
Fig. 6. HD – axial (A) and coronal (B) T2W images show decreased volume of head of caudate nuclei (red arrows) with secondary enlargement of frontal horns. There is visible hyperintensity of caudate nuclei (red arrow) and putamina (blue arrow).
Fig. 3. MSA-P shows pronounced atrophy of putamina (arrows) and their high signal intensity on T2WI (A), FLAIR (B) and very low signal intensity DWI (C) and SWI (not shown) resulting from increased iron content.
REFERENCES:
1. Meijer FJ et al. Contribution of routine brain MRI to the differential diagnosis of
parkinsonism: a 3-year prospective follow-up study. J Neurol. 2012
May;259(5):
2. Kanekar, Sangam G., Imaging of Neurodegenerative Disorders, Thieme, 2016
3. Images: Department od General and Interventional Radiology and Neuroradiology, Wroclaw University Hospital, Wroclaw, Poland
CONCLUSIONS:
Structural magnetic resonance imaging is a useful tool in establishing diagnosis of neurodegenerative diseases ongoing with dementia symptoms and helps in differentiating these conditionts. DWI as well as SWI sequences should be incorporated in the routine MR protocol dedicated to neurodegerative disorders assessment.