A 64-Year-Old Woman With Bradykinesia and Rigidity

Discussion

Differentiating idiopathic Parkinson's disease from other parkinsonian states may be difficult by clinical findings alone. Neuroimaging can be a useful tool in the diagnosis of patients. This patient most likely had parkinsonism due to a Parkinson's plus syndrome -- the SND subtype of MSA. MRI was strongly suggestive of SND, with a combination of hypointensity of the posterior putamen and hyperintensity of the lateral border of the putamen (Figure 2).

(Enlarge Image)

Figure 2.

Same images as Figure 1 with arrows added to show the pertinent findings.

The hypointensity of the putamen in SND has been related to pathologic iron deposition. The hyperintensity in the lateral rim of the putamen is most likely due to neuronal loss and gliosis. Other MRI findings in SND/MSA include atrophy of the pons, putamen, cerebellum, middle cerebellar peduncle, and midbrain, and the pontine "hot-crossed-bun sign".

The hyperintense lesions of the lateral putamen in this case are shown especially well by FLAIR, compared with images generated by standard T2-weighted imaging (Figure 2). Because of the high TR (repetition time) and high TE (time to echo), the type of FLAIR used in the present case for brain imaging (and on most modern MRI scanners) is a strongly T2-weighted sequence. A 180-degree pulse is added to suppress cerebrospinal fluid (CSF), providing high lesion-to-tissue contrast. FLAIR has increased the sensitivity of MRI in a variety of brain diseases including stroke, hemorrhage, and multiple sclerosis. Our case shows that FLAIR contributes to the MRI evaluation of patients with atypical parkinsonism. The MRI findings in SND are summarized in Table 1.

Parkinson's disease, characterized by Lewy body formation in the substantia nigra, may show hypointensity on T2-weighted imaging of the substantia nigra (probably due to iron deposition), causing a blurring of the normal isointense margin (pars compacta) between the red nucleus and the pars reticulata of the substantia nigra. This finding is of uncertain sensitivity and specificity. Other nonspecific changes may occur in Parkinson's disease (diffuse cortical atrophy white matter hyperintensities). The presence of age-inappropriate T2 hypointensity of the putamen or selective atrophy of the brain stem or cerebellum favors a Parkinson's plus syndrome instead of Parkinson's disease.

The Parkinson's plus syndromes are summarized in Table 2.

Parkinson's plus syndromes include olivopontocerebellar atrophy (OPCA), SND, Shy-Drager syndrome, progressive supranuclear palsy, corticobasalganglionic degeneration (CBGD), and Lewy body dementia (Table 2). Neuroimaging may be helpful in distinguishing these conditions from Parkinson's disease, as summarized in Table 3. Hypointensity of the putamen on T2-weighted imaging is most commonly found in CBGD, SND, Shy-Drager syndrome, and OPCA. Selective atrophy of the pons, medulla, cerebellar vermis, and cerebellar hemispheres suggests OPCA, which is best viewed on sagittal T1-weighted images. Selective atrophy of the dorsal midbrain and quadrigeminal plate points to PSP. CBDG is characterized by asymmetric cortical atrophy and lenticular hypointensity on T2-weighted imaging. Functional imaging studies (SPECT/PET) usually show decreased basal ganglia perfusion/metabolism in patients with SND/MSA and other forms of atypical parkinsonism, expected in the present case. In contrast, Parkinson's disease is characterized by increased perfusion/metabolism in the basal ganglia. A summary of the neuroimaging findings in atypical parkinsonism is shown in Table 3.

Medscape Neurology. 2001;3(2) © 2001  Medscape

Cite this: A 64-Year-Old Woman With Bradykinesia and Rigidity - Medscape - Sep 27, 2001.