This small Brazilian study looked at 11 patients with PSP, 7 patients with MSA-P, 12 patients with PD, and 10 controls. Everyone was studied with magnetic resonance imaging (MRI) and spectroscopy by MRI (MRS).
The authors concluded:
“(1) Patients with PSP and MSA-P presented increased motor and cognitive impairment in the scales used, correlating with decrease in NAA/Cr in lentiform nucleus and NAA/Cho in midbrain in the PSP group;
(2) Cerebral and cerebellar atrophy were more prevalent and severe in PSP and MSA-P groups;
(3) Linear hypersignal in the lateral portion of the putamen, hypersignal in midbrain and in pons, all suggest the diagnosis of PSP or MSA-P;
(4) Midbrain or pons atrophy suggests atypical parkinsonism, the former PSP, and the latter MSA-P;
(5) Comparing the two methods, MRI and MRS, the former had better applicability.”
The abstract and lots of excerpts follow. The English-language article is available for free online here:
http://www.scielo.br/pdf/anp/v67n1/a02v67n1.pdf –> PDF form
http://www.scielo.br/scielo.php?script= … so&tlng=en –> HTML form
For me, the most interesting parts of this article were the three figures with captions, indicating what percentage of the patient groups had particular MRI or MRS findings, including the hot cross bun sign in MSA. (You’ll have to go online to see the figures.) And the Discussion section was worthwhile reading.
Robin
Arqivos de Neuropsiquiatria. 2009 Mar;67(1):1-6.
Neuroimaging in Parkinsonism: a study with magnetic resonance and spectroscopy as tools in the differential diagnosis.
Vasconcellos LF, Novis SA, Moreira DM, Rosso AL, Leite AC.
Hospital dos Servidores do Estado, Rio de Janeiro, RJ, Brazil.
The differential diagnosis of Parkinsonism based on clinical features, sometimes may be difficult. Diagnostic tests in these cases might be useful, especially magnetic resonance imaging, a noninvasive exam, not as expensive as positron emission tomography, and provides a good basis for anatomical analysis. The magnetic resonance spectroscopy analyzes cerebral metabolism, yielding inconsistent results in parkinsonian disorders.
We selected 40 individuals for magnetic resonance imaging and spectroscopy analysis, 12 with Parkinson’s disease, 11 with progressive supranuclear palsy, 7 with multiple system atrophy (parkinsonian type), and 10 individuals without any psychiatric or neurological disorders (controls). Clinical scales included Hoenh and Yahr, unified Parkinson’s disease rating scale and mini mental status examination.
The results showed that patients with Parkinson’s disease and controls presented the same aspects on neuroimaging, with few or absence of abnormalities, and supranuclear progressive palsy and multiple system atrophy showed abnormalities, some of which statistically significant. Thus, magnetic resonance imaging and spectroscopy could be useful as a tool in differential diagnosis of Parkinsonism.
PubMed ID#: 19330200
Here are excerpts from the full article:
“Magnetic resonance imaging (MRI) and spectroscopy by MRI (MRS) are noninvasive tools helping the physician to establish a more accurate diagnosis. MRI offers an adequate analysis of abnormalities in the basal nuclei, midbrain, pons, medulla, and cerebellum, which are impaired in atypical” parkinsonism.
“Method
We designed a prospective, case-control, double-blind, 24 months study. The MRI was performed in a GE machine, 1.5 Tesla Sigma Horizon model, the sequences analyzed were T 1, T 2, flair, diffusion, axial-oblique in T 2 in Fast Spin-Echo (FSE) and Proton Density (PD) and T 2 in Spin-Echo (SE). In addition to 5 mm slices, we included 3 mm slices in the lentiform nucleus. The MRS was single voxel (8 cc), PRESS technique (TR/TE=1500/50) bilaterally in lentiform nucleus, midbrain, white matter of frontal lobe and hippocampus.” …
“Forty individuals were included in this study (age range: 50 to 85 years), 30 with Parkinsonian syndrome and 10 without any neurological or psychiatric disorders.”
“All individuals were examined by the same neurologist, and 26 patients met the criteria for probable Parkinson’s disease (PD) [n=10], (Gelb et al.), progressive supranuclear palsy (PSP) [n=10], (Tolosa et al.), and multiple system atrophy-parkinsonian type (MSA-P) [n=6], (Gilman et al.). For clinical assessment, the scales adopted were Hoehn-Yahr stage, unified Parkinson’s disease rating scale (UPDRS) Part III and mini-mental status examination (MMSE). The patients performed the Tilt Table test for evaluation of dysautonomia.”
“Results …
Dysautonomia was documented in 20% of PD and 100% of MSA-P.
In the motor scales (UPDRS and Hoehn and Yahr), the results showed higher scores in PSP and MSA-P than in PD. There was statistical significance in PD versus MSA-P, and a trend to statistical significance in PD and PSP.
Patients with PSP presented lower scores in MMSE, followed by MSA-P and PD, and there was statistical significance in the three groups comparing to controls (Table 1).
Image variables demonstrated cerebral atrophy in all cases of PSP and MSA-P, having statistical significance in PD versus PSP, PD versus MSA-P, controls versus PSP, and controls versus MSA-P. Cerebellar atrophy was more common in MSA-P and PSP, with statistical significance in PD versus MSA-P, controls versus PSP and controls versus MSA-P. We observed a higher prevalence of white matter alterations in atypical [parkinsonism] with no statistical significance. Signal change in the lentiform nucleus was observed more commonly in MSA-P and PSP, but no statistical significance was documented (Figs 13).”
Fig 1. Hyposignal in the lentiform nucleus (found in 67% of MSA-P group), and hypersignal in the pons (found in 33% of the MSA-P group) and the midbrain on T2, flair or DP sequences (found in 70% of PSP group).
Fig 2. Posterolateral linear hypersignal in the lentiform nucleus with asymmetric symptoms, T2 sequence (found in 50% in MSA-P group).
Fig 3. Transverse signal (“hot cross bun sign”) in the pons, T2 sequence (found in 33% of MSA-P group).” …
“DISCUSSION
…Parkinsonian signs may be seen in different medical conditions, having variable course, treatment and prognosis so it is important to determine an accurate diagnosis as soon as possible. Based only in clinical data, especially in the early stages of the disease, physicians may not establish a correct diagnosis.
… One study conducted in a movement disorders specialized center, showed that the positive predictive value of PD was 98.6%, and to atypical parkinsonism 71.4%, confirming that the diagnosis of atypical [parkinsonism], even in specialized centers, is sometimes difficult to establish.
… We included the three [parkinsonism syndromes] that most frequently lead to misdiagnosis: PD, MSA-P, and PSP, all compared to control group. …
We used three clinical scales: motor part of UPDRS, Hoehn and Yahr and MMSE. These scales showed increased motor impairment (higher scores in UPDRS and Hoehn-Yahr) in the MSA-P, followed by PSP, and increased cognitive impairment (lower scores of MMSE) in PSP, followed by MSA-P. We did not observe a correlation between the duration of the symptoms with MRS abnormalities, but with the clinical diagnosis of patient.
MRI variables demonstrated that some are helpful to differentiated [parkinsonism] syndromes, as the presence of cerebral and cerebellar atrophy and signal enhancement of some encephalic structures (lentiform nucleus, midbrain and pons), more common in atypical [parkinsonism].
The decreased signal enhancement in the lentiform nucleus may be observed in normal aging, so in our study we only considered it as ‘abnormal’ if the hypointensity was moderate to severe. Our data showed that moderate to severe decrease hypointensity in lentiform nucleus was observed more frequently in MSA and PSP, with no difference between PD and control groups and when it was associated with posterolateral linear hypersignal in putamen, suggested the diagnosis of atypical [parkinsonism] (more frequently in MSA group).
The most useful measurement of encephalic diameter in our study was the midbrain, as it had been shown by Warmutth et al. Values below 15 mm in the midbrain suggested PSP or MSA-P, with lower values seen in PSP.
Some values of MRS had statistical significance, the most useful were from the lentiform nucleus, hippocampus, and midbrain, depending on the diagnosis, indicating a severe neuronal impairment (neuronal death). There are few studies in which the brainstem is evaluated by MRS, due to technical difficulties (bone proximity). In our study we demonstrated that it is feasible, but we had to repeat the exam, in some cases several times, to achieve a consistent chart. The study done by Watanabe et al. demonstrated the usefulness of MRS of the pons in MSA patients. As the midbrain is the most affected area in PSP, we analyzed it by MRS. We have found NAA/Cho decrease in midbrain of PSP group with statistical significance, indicating neuronal loss.
Based on our data we concluded that:
(1) Patients with PSP and MSA-P presented increased motor and cognitive impairment in the scales used, correlating with decrease in NAA/Cr in lentiform nucleus and NAA/Cho in midbrain in the PSP group;
(2) Cerebral and cerebellar atrophy were more prevalent and severe in PSP and MSA-P groups;
(3) Linear hypersignal in the lateral portion of the putamen, hypersignal in midbrain and in pons, all suggest the diagnosis of PSP or MSA-P;
(4) Midbrain or pons atrophy suggests atypical parkinsonism, the former PSP, and the latter MSA-P;
(5) Comparing the two methods, MRI and MRS, the former had better applicability.
Our study showed that anatomical analysis through MRI and MRS of some areas could be useful in the differential diagnosis of PD and atypical [parkinsonism], helping physicians to establish a more accurate diagnosis of [parkinsonian syndromes].”