Putaminal Hypointensity Research Articles

Diagnostic Performance of Putaminal Hypointensity on Susceptibility MRI in Distinguishing Parkinson Disease from Progressive Supranuclear Palsy: A Meta-Analysis.

Idiopathic Parkinson's disease (IPD) and progressive supranuclear palsy (PSP) have similar clinical signs and symptoms, making accurate clinical diagnosis difficult. T2* gradient echo (T2* GRE), susceptibility-weighted imaging (SWI), and quantitative susceptibility mapping (QSM) are susceptibility MR imaging sequences that provide more information about brain iron levels than other conventional MR imaging. This study aimed to evaluate the diagnostic power of putaminal hypointensity on T2* GRE, SWI, and QSM in distinguishing PSP from IPD. Eligible studies were identified via systematic searches of PubMed and Clarivate Analytics® Web of Science® Core Collection. Studies that satisfied the inclusion and exclusion criteria were reviewed. A meta-analysis was conducted using the hierarchical summary receiver operating characteristic curve approach. Our literature search of the two databases yielded 562 primary articles, 10 of which were deemed relevant and only six were eligible for further analyses. We performed a meta-analysis of putaminal hypointensity measurements: 438 patients with IPD and 109 patients with PSP were enrolled in the quantitative synthesis. The meta-analysis of six studies with 547 patients revealed a sensitivity of 69% (95% confidence interval (CI): 33%-90%) and specificity of 91% (95% CI: 80%-96%) for putaminal hypointensity on T2* GRE, SWI, or QSM distinguishing PSP from IPD. Putaminal hypointensity on T2* GRE, SWI, or QSM is able to distinguish patients with PSP from those with IPD with high specificity. Further multicenter prospective studies on patients are needed to verify our results.

The "Black Straight-Line Sign" in the Putamen in Diffusion-Weighted Imaging: A Potential Diagnostic MRI Marker for Multiple System Atrophy.

Background and PurposeThe diagnosis of multiple system atrophy (MSA) remains challenging in clinical practice. This study investigated the value of hypointense signals in the putamen (“black straight-line sign”) in diffusion-weighted imaging (DWI) of brain MRI for distinguishing (MSA) from Parkinson's disease (PD).MethodsWe retrospectively enrolled 30 MSA patients, 30 PD patients, and 30 healthy controls who had undergone brain MRI between 2016 and 2020. Two readers independently assessed the signal intensity of the bilateral putamen on DWI. The putaminal hypointensity was scored using 4-point visual scales. Putaminal hypointensity and the presence of a “black straight-line sign” were statistically compared between MSA and PD or healthy controls.ResultsThe mean scores of putaminal hypointensity in DWI in the MSA group were significantly higher than in both the PD (U = 315.5, P = 0.034) and healthy control groups (U = 304.0, P = 0.022). Uni- or bilateral putaminal hypointensity in DWI with a score ≥2 was identified in 53.3% (16/30), 16.7% (5/30), and 13.3% (4/30) of MSA, PD, and healthy controls, respectively, with significant differences between MSA and PD (X2 = 8.864, P = 0.003) or healthy controls (X2 = 10.800, P = 0.001). Notably, the “black straight-line sign” of the putamen was observed in 16/30 (sensitivity 53.3%) patients with MSA, while it was absent in PD and healthy controls (specificity 100%). There were no significant differences for the presence of “black straight-line sign” in the MSA-P and MSA-C groups (X2 = 0.433, P = 0.510).ConclusionThe “black straight-line sign” of the putamen in DWI of head MRIs has the potential to serve as a diagnostic marker for distinguishing MSA from PD.

Nigrosome and Neuromelanin Imaging as Tools to Differentiate Parkinson's Disease and Parkinsonism.

Parkinson's disease (PD) lacks a definitive diagnosis due to a lack of pathological validation of patients at antemortem. The risk of misdiagnosis is high in the early stages of PD, often eluded by atypical parkinsonian symptoms. Neuroimaging and laboratory biomarkers are being sought to aid in the clinical diagnosis of PD. Nigrosome imaging and neuromelanin (NM)-sensitive magnetic resonance imaging (MRI) are the new emerging tools, both technically simple plus cost-effective for studying nigral pathology, and have shown potential for authenticating the clinical diagnosis of PD. Visual assessment of the nigrosome-1 appearance, at 3 or 7 Tesla, yields excellent diagnostic accuracy for differentiating idiopathic PD from healthy controls. Moreover, midbrain atrophy and putaminal hypointensity in nigrosome-1 imaging are valid pointers in distinguishing PD from allied parkinsonian disorders. The majority of studies employed T2 and susceptibility-weighted imaging MRI sequences to visualize nigrosome abnormalities, whereas T1-weighted fast-spin echo sequences were used for NM imaging. The diagnostic performance of NM-sensitive MRI in discriminating PD from normal HC can be improved further. Longitudinal studies with adequate sampling of varied uncertain PD cases should be designed to accurately evaluate the sensitivity and diagnostic potential of nigrosome and NM imaging techniques. Equal weightage is to be given to uniformity and standardization of protocols, data analysis, and interpretation of results. There is tremendous scope for identifying disease-specific structural changes in varied forms of parkinsonism with these low-cost imaging tools. Nigrosome-1 and midbrain NM imaging may not only provide an accurate diagnosis of PD but could mature into tools for personally tailored treatment and prognosis.

Diagnostic performance of T2* gradient echo, susceptibility-weighted imaging, and quantitative susceptibility mapping for patients with multiple system atrophy-parkinsonian type: a systematic review and meta-analysis.

To investigate the diagnostic performance of T2*-weighted gradient echo (GRE) imaging, susceptibility-weighted imaging (SWI), or quantitative susceptibility mapping (QSM) in differentiating multiple system atrophy-parkinsonian type (MSA-P) from Parkinson's disease (PD). A systematic literature search through the MEDLINE and EMBASE databases was performed, starting on September 8, 2020, to identify studies evaluating the diagnostic performance of putaminal hypointensity on T2* GRE or SWI and phase shift on QSM in differentiating MSA-P from PD. The pooled sensitivity and specificity were obtained using hierarchical logistic regression modeling and hierarchical summary receiver operating characteristic (HSROC) modeling. The pooled diagnostic yields of T2* GRE, SWI, or QSM among MSA-P patients were calculated using the DerSimonian-Laird random-effects model. Twelve original articles with 985 patients were finally included. SWI was performed in seven studies, T2* GRE was performed in three studies, and QSM was performed in two studies. The pooled sensitivity and specificity were 0.65 (95% CI 0.51-0.78) and 0.90 (95% CI 0.83-0.95), respectively. The area under the HSROC curve was 0.87 (95% CI 0.84-0.90). The Higgins I2 statistic calculations revealed considerable heterogeneity in terms of both sensitivity (I2 = 72.12%) and specificity (I2 = 70.38%). The coupled forest plot revealed the threshold effect. For the nine studies in which area under the curve (AUC) was obtainable, the AUC ranged from 0.68 to 0.947, with a median of 0.819. The pooled diagnostic yield of T2* GRE, SWI, or QSM was 66% (95% CI 51-78%). Putaminal hypointensity on T2* GRE or SWI and phase shift on QSM might be a promising diagnostic tool in differentiating MSA-P from PD. Further large multicenter prospective study is warranted. • Three different index tests, definitions of positive image findings, thresholds, the way how to draw ROIs, reference standard, and MRI parameters could affect the heterogeneity of the study. • The pooled sensitivity and specificity were 0.65 (95% CI 0.51-0.78) and 0.90 (95% CI 0.83-0.95), respectively. • The pooled diagnostic yield of T2* GRE, SWI, or QSM was 66% (95% CI 51-78%).

Incidental evidence of hypointensity in brain grey nuclei on routine MR imaging: when to suspect a neurodegenerative disorder?

Deep grey nuclei of the human brain accumulate minerals both in aging and in several neurodegenerative diseases. Mineral deposition produces a shortening of the transverse relaxation time which causes hypointensity on magnetic resonance (MR) imaging. The physician often has difficulties in determining whether the incidental hypointensity of grey nuclei seen on MR images is related to aging or neurodegenerative pathology. We investigated the hypointensity patterns in globus pallidus, putamen, caudate nucleus, thalamus and dentate nucleus of 217 healthy subjects (ages, 20-79 years; men/women, 104/113) using 3T MR imaging. Hypointensity was detected more frequently in globus pallidus (35.5%) than in dentate nucleus (32.7%) and putamen (7.8%). A consistent effect of aging on hypointensity (p < 0.001) of these grey nuclei was evident. Putaminal hypointensity appeared only in elderly subjects whereas we did not find hypointensity in the caudate nucleus and thalamus of any subject. In conclusion, the evidence of hypointensity in the caudate nucleus and thalamus at any age or hypointensity in the putamen seen in young subjects should prompt the clinician to consider a neurodegenerative disease.

“Putaminal hypo-intensity (PUT-hypo)” on Susceptibility-Weighted Imaging (SWI) in Parkinsonism Predominant Multiple System Atrophy (MSA-P): Comparison between Parkinson’s Disease (PD) and Age-matched Controls without Parkinsonism (991)

“Putaminal hypo-intensity (PUT-hypo)” on Susceptibility-Weighted Imaging (SWI) in Parkinsonism Predominant Multiple System Atrophy (MSA-P): Comparison between Parkinson’s Disease (PD) and Age-matched Controls without Parkinsonism (991)

Brain MRI of multiple system atrophy of cerebellar type: a prospective study with implications for diagnosis criteria.

The second consensus statement for the diagnosis of multiple system atrophy type cerebellar (MSA-C) includes pons and middle cerebellar peduncle (MCP) atrophy as MRI features. However, other MRI abnormalities such as MCP hyperintensity, hot cross bun sign (HCB), putaminal hypointensity and hyperintense putaminal rim have been described. To evaluate, in patients with sporadic late-onset cerebellar ataxia (SLOCA), the discriminative value of several MRI features for the diagnosis of MSA-C, to follow their evolution during the course of MSA-C, and to search for correlations between these MRI features and clinical signs. Consecutive patients referred for SLOCA underwent comprehensive clinical evaluation and laboratory investigations, brain MRI, DaTscan and a 1-year follow-up. Among 80 patients, 26 had MSA-C, 22 another diagnosis, and 32 no diagnosis at the end of the follow-up. At baseline, MCP hyperintensity and HCB were more frequent in patients finally diagnosed with MSA-C than in other patients with SLOCA (p < 0.0001), and had the highest specificity (98.5%) and positive predictive value (91.7%) for the diagnosis of MSA-C, compared to all other MRI signs. The most relevant MRI sequence regarding HCB sign was the T2-proton density (DP) weighted. All MRI features were more frequent with disease duration. No correlation was found between any MRI feature and neither clinical data, nor dopaminergic neuronal loss (p = 0.5008), except between vermis atrophy and UPDRSIII score. MCP hyperintensity and HCB sign should be added into the list of additional features of possible MSA-C. MRI signal abnormalities suggestive of MSA-C should be searched for in suitable sequence.

Quantitative Validation of a Visual Rating Scale for Defining High-Iron Putamen in Patients With Multiple System Atrophy.

Objectives: To validate a visual rating scale reflecting sub-regional patterns of putaminal hypointensity in susceptibility-weighted imaging of patients with multiple system atrophy (MSA).Methods: Using a visual rating scale (from G0 to G3), 2 examiners independently rated putaminal hypointensities of 37 MSA patients and 21 control subjects. To investigate the correlation with the scales, R2* values and the volume of the entire putamen were measured.Results: MSA patients with parkinsonian variant had significantly higher scores than those with cerebellar variant. Visual rating scores in MSA were correlated with R2* values [General estimating equation (GEE), Wald chi-square = 25.89, corrected p < 0.001] and volume (Wald chi-square = 75.44, corrected p < 0.001). They correlated with UPDRS motor scores. Binary logistic regression analyses revealed that the visual rating scale was a significant predictor for discriminating MSA patients from controls [multivariate model adjusted for age and sex, odds ratio 52.722 (corrected p = 0.009)]. Pairwise comparison between areas under the curve (AUCs) revealed that the visual rating scale demonstrated higher accuracy than R2* values [difference between AUCs; univariate model = 0.247 (corrected p < 0.001); multivariate model = 0.186 (corrected p = 0.003)]. There were no significant differences in clinical characteristics between the high-iron group, defined as putamen with visual rating scale ≥ G2 and R2* values ≥ third quartile, and the remaining patients.Conclusion: The visual rating scale, which reflects quantitative iron content and atrophy of the putamen as well as motor severities, could be useful for the discrimination and evaluation of patients with MSA.

Multiparametric MR imaging of Parkinsonisms at 3 tesla: Its role in the differentiation of idiopathic Parkinson’s disease versus atypical Parkinsonian disorders

ObjectivesThe Nigrosome-1 and putaminal hypointensity depicted on susceptibility-weighted imaging (SWI), and midbrain atrophy assessed on T1-weighted are some of the most common radiological parameters to diagnose Parkinsonism at Magnetic Resonance (MR) imaging. Our aim is to assess the feasibility of these signs in the differentiation of Idiopathic Parkinson’s disease (IPD) patients versus disease (DC) and healthy controls (HC) and in the assessment of the Atypical Progressive Parkinsonisms (APPs). MethodsPresence or loss of the Nigrosome-1 was assessed retrospectively on multiple-echo SWI obtained on a 3 T scan by two neuroradiologists. Results were compared with the 123I-FP-CIT SPECT images. Morphologic diagnostic features suggestive of APPs such as midbrain atrophy and putaminal hypointensity were evaluated by qualitative scores. The midbrain and putaminal scores were summed (combined score) and then added to the Nigrosome-1 score (global score). ResultsThe study included 126 patients with IPD (n = 56), APPs patients (n = 30; 18 PSP, 3 MSA-C, 9 MSA-P), 16 DC and 24 HC. Sensitivity and specificity of the Nigrosome-1 in discriminating IPD from controls were 96,43% and 85.00%, APPs from controls were 100% and 85%, IPD from APPs were 96,43% and 0% respectively. Combined score for midbrain atrophy and putaminal hypointensity resulted in the most accurate for distinguishing APPs from IPD with a value of ≥ 2 (AUC = 0.98). ConclusionNigrosome-1 is a valid tool to differentiate IPD-APPs from controls. The combined score of midbrain atrophy and putaminal hypointensity represents a valid diagnostic pointer in the differential diagnosis of APPs from IPD.

Using 'swallow-tail' sign and putaminal hypointensity as biomarkers to distinguish multiple system atrophy from idiopathic Parkinson's disease: A susceptibility-weighted imaging study.

To investigate the value of 'swallow-tail' sign and putaminal hypointensity on 3T susceptibility-weighted imaging (SWI) for distinguishing multiple system atrophy (MSA) from idiopathic Parkinson's disease (IPD). Three groups - 39 MSA patients, 18 IPD patients,and 31 healthy controls (HCs) - were administered a 3T SWI sequence to evaluate 'swallow-tail' sign and putaminal hypointensity using visual scales from 0 to 2 and 0 to 3 scores, respectively. The diagnostic accuracy of the two signs separately and combined was calculated using a receiver operating characteristic curve, with clinical diagnosis as the gold standard. The scores of 'swallow-tail' sign were lower in IPD than in MSA or in HCs, as well as for putaminal hypointensity in IPD or HCs than in MSA (p < 0.05). The sensitivity and specificity of 'swallow-tail' sign and putaminal hypointensity were 87.9% and 83.3%, and 35.9% and 100%, respectively, in the respective patient groups. The area under the curve of combined signs was increased from 0.85 ('swallow tail') or 0.68 (putaminal hypointensity) to 0.93. The combination of 'swallow-tail' sign and putaminal hypointensity can increase the accuracy of discriminating between MSA and IPD. • Differential diagnosis of MSA and IPD is still challenging in clinical practice. • Absence of 'swallow-tail' sign is a valuable biomarker for IPD on SWI. • Putaminal hypointensity is a valuable biomarker for MSA on SWI. • Combined 'swallow- tail' sign and putaminal hypointensity increase diagnostic accuracy.

Susceptibility-weighted MRI of extrapyramidal brain structures in Parkinsonian disorders.

Susceptibility-weighted MRI (SWI) is sensitive to T2∗ effects and mineralization.We investigated differences in the extrapyramidal brain structures on SWI between Parkinson disease (PD) and postural instability gait disorder (PIGD) patients and correlated the SWI values with the degree of gait dysfunction.Forty patients diagnosed with PD and PIGD underwent 3 Tesla magnetic resonance imaging (MRI) brain study. An SWI sequence (TE/TR/FA 20/33/15) was used. Ten regions of interest were placed in the midbrain and basal ganglia by 2 independent raters blinded to subject data and quantitatively evaluated.The inter-rater reliability between the raters was excellent (interclass correlation coefficient >0.8). The SWI intensity values in all regions were on average lower in PIGD than in PD patients, with the lowest results found in globus pallidus.Multivariate analysis showed a lower SWI hypointensity in the putamen and globus pallidus in PIGD compared with PD patients, with a similar trend for the other basal ganglia nuclei. Pearson correlation analysis showed a statistically significant positive correlation between SWI putaminal hypointensity and the Tinetti total score (r = 0.39, P = 0.01) in both PD and PIGD.SWI putaminal hypointensity may be a useful imaging marker in prospective evaluation for clinical progression for Parkinsonian disorders.

Significance of the hot-cross bun sign on T2*-weighted MRI for the diagnosis of multiple system atrophy.

Although the sensitive detection of putaminal iron deposition by T2*-weighted imaging (T2*-WI) is of diagnostic value for multiple system atrophy (MSA), the diagnostic significance of the pontine hot-cross bun (HCB) sign with increased ferritin-bound iron in the background remains unknown. We retrospectively evaluated the cases of 33 patients with cerebellar-form MSA (MSA-C) and 21 with MSA of the parkinsonian form (MSA-P) who underwent an MRI study with a 1.5-T system. Visualization of the HCB sign, posterior putaminal hypointensity and putaminal hyperintense rim on T2*-WI was assessed by two neurologists independently using an established visual grade, and were compared with those on T2-weighted imaging (T2-WI). The visual grade of pontine and putaminal signal changes was separately assessed for probable MSA (advanced stage) and possible MSA (early stage). T2*-WI demonstrated significantly higher grades of HCB sign than T2-WI (probable MSA-C, n = 27, p < 0.001; possible MSA-C, n = 6, p < 0.05; probable MSA-P, n = 13, p < 0.01). The visual grade of the HCB sign on T2*-WI in the possible MSA-C patients was comparable to that in the probable MSA-C patients. Although the HCB sign in MSA-P was of lower visual grade than in MSA-C even on T2*-WI, some patients showed evolution of the HCB sign preceding the appearance of the putaminal changes. These findings suggest that T2*-WI is of extreme value for detecting the HCB sign, which is often cited as a hallmark of MSA. The appearance of the HCB sign on T2*-WI might not only support but also improve the diagnosis of MSA.

The putaminal abnormalities on 3.0T magnetic resonance imaging: can they separate parkinsonism-predominant multiple system atrophy from Parkinson's disease?

The putaminal abnormalities detected on 1.5 T magnetic resonance imaging (MRI), such as putaminal atrophy, slit-like hyperintense rim, and hypointensity in the putamen on T2-weighted (T2W) imaging are important signs on differentiating multiple system atrophy with parkinsonism (MSA-P) from Parkinson's disease (PD). However, the putaminal abnormalities may have different manifestations on 3.0 T from those on 1.5 T. To investigate the diagnostic value of putaminal abnormalities on 3.0 T MRI for differentiating MSA-P from PD. The study included a MSA-P group (9 men, 9 women), a PD group (12 men, 14 women), and a control group (11 men, 13 women). All subjects were examined with 3.0 T MRI using the conventional protocol. Putaminal atrophy, T2-hypointensity in the dorsolateral putamenat, and a slit-like hyperintense rim on the lateral putamen were evaluated in each subject. There were no significant differences in the slit-like hyperintense rim (P = 0.782) or T2-hypointensity in the dorsolateral putamen (P = 0.338) among the three groups. Bilateral putaminal atrophy was found in 44.4% (8 of 18) of the MSA-P patients, in only 7.7% (2 of 26) of the PD patients, and in none of the controls. The proportion of subjects with putaminal atrophy was significantly higher in the MAS-P group (P = 0.008) and control group (P < 0.001). The specificity and sensitivity of putaminal atrophy for distinguishing MSA-P from PD was 92.3% and 44.4%, respectively. The signal changes in the putamen on T2W imaging on 3.0 T MRI, including slit-like hyperintense rim and putaminal hypointensity, are not specific signs for MSA-P. Putaminal atrophy is highly specific for differentiating MSA-P from PD and healthy controls, but its insufficient sensitivity limits its diagnostic value.

Putaminal hypointensity on T2*-weighted MR imaging is the most practically useful sign in diagnosing multiple system atrophy: A preliminary study

ObjectiveTo identify useful MRI abnormalities in the putamen for diagnosing multiple system atrophy. MethodsPatients with multiple system atrophy (n=15), Parkinson's disease (n=16), or progressive supranuclear palsy (n=9) and healthy controls (n=10) were enrolled. Using a visual analog scale, 4 examiners independently rated high-intensity signals along the lateral putamen on T2-weighted and T2*-weighted images, low-intensity signals within the putamen on T2-weighted and T2*-weighted images, and putaminal atrophy. Receiver operating characteristic analyses were performed, and the area under the receiver operating characteristic curve was calculated. ResultsFor differentiating multiple system atrophy from progressive supranuclear palsy, Parkinson's disease, and healthy controls, the mean area under the curve values was the highest for low-intensity signals within the putamen on T2*-weighted images (0.797, 0.867, 0.896, respectively). Variations in the area under the curve values among the 4 examiners were the smallest in low-intensity signals within the putamen on T2*-weighted images. Good inter-rater reliability was achieved for low-intensity signals within the putamen on T2*-weighted images and high-intensity signals along the lateral putamen on T2*-weighted images. ConclusionLow-intensity signals within the putamen on T2*-weighted images is the most useful MRI abnormality for diagnosing multiple system atrophy.

Susceptibility-weighted imaging improves the diagnostic accuracy of 3T brain MRI in the work-up of parkinsonism.

The differentiation between Parkinson disease and atypical parkinsonian syndromes can be challenging in clinical practice, especially in early disease stages. Brain MR imaging can help to increase certainty about the diagnosis. Our goal was to evaluate the added value of SWI in relation to conventional 3T brain MR imaging for the diagnostic work-up of early-stage parkinsonism. This was a prospective observational cohort study of 65 patients presenting with parkinsonism but with an uncertain initial clinical diagnosis. At baseline, 3T brain MR imaging with conventional and SWI sequences was performed. After clinical follow-up, probable diagnoses could be made in 56 patients, 38 patients diagnosed with Parkinson disease and 18 patients diagnosed with atypical parkinsonian syndromes, including 12 patients diagnosed with multiple system atrophy-parkinsonian form. In addition, 13 healthy controls were evaluated with SWI. Abnormal findings on conventional brain MR imaging were grouped into disease-specific scores. SWI was analyzed by a region-of-interest method of different brain structures. One-way ANOVA was performed to analyze group differences. Receiver operating characteristic analyses were performed to evaluate the diagnostic accuracy of conventional brain MR imaging separately and combined with SWI. Disease-specific scores of conventional brain MR imaging had a high specificity for atypical parkinsonian syndromes (80%-90%), but sensitivity was limited (50%-80%). The mean SWI signal intensity of the putamen was significantly lower for multiple system atrophy-parkinsonian form than for Parkinson disease and controls (P < .001). The presence of severe dorsal putaminal hypointensity improved the accuracy of brain MR imaging: The area under the curve was increased from 0.75 to 0.83 for identifying multiple system atrophy-parkinsonian form, and it was increased from 0.76 to 0.82 for identifying atypical parkinsonian syndromes as a group. SWI improves the diagnostic accuracy of 3T brain MR imaging in the work-up of parkinsonism by identifying severe putaminal hypointensity as a sign indicative of multiple system atrophy-parkinsonian form.

Susceptibility Weighted Imaging Features of Nonketotic Hyperglycemia: Unusual Cause of Hemichorea‐Hemiballismus

Nonketotic hyperglycemia has been described as a metabolic cause of Hemiballism-hemichorea (HB-HC), especially in elderly patients with poorly controlled diabetes. Pathophysiology is not known yet. MRI features tend to be hyperintense in the putamen on T1-weighted images. We present conventional MRI with diffusion weighted imaging (DWI) and susceptibility weighted imaging (SWI) features of two cases with nonketotic hyperglycemia. T1 hyperintensity without diffusion restriction on DWI and minimal putaminal hypointensity without phase shift on SWI were compatible with either pathological mineralization or petechial microhemorrhage or protein denaturation. In the type 2 diabetic patients with HC-HB, conventional MRI together with SWI and DWI will guide to clinician to plan treatment approach.

Putaminal hypointensity in the parkinsonian variant of multiple system atrophy: simple visual assessment using susceptibility-weighted imaging.

Background and PurposeSusceptibility-weighted imaging (SWI) has been shown to be superior in its ability to demonstrate brain mineralization than other conventional MR imaging. The goal of our study was therefore to assess the frequency and extent of putaminal hypointensity in parkinsonian variant MSA using SWI.Methods11 patients with multiple system atrophy-parkinsonian type (MSA-p), 30 patients with Parkinson’s disease (PD), and age matched 30 controls were investigated using 3 Tesla MRI. The pattern of putaminal hypointensity was measured using a visual grading scale and scored from 0 to 3.ResultsHemi- or bilateral putaminal hypointensity (a score of ≥ 2) and hyperintense rim were recognized in 81.8% and 54.5% of 11 MSA-p, respectively. The scores of putaminal hypointensity of MSA-p were significantly higher than other groups (p < 0.001), a score of ≥ 2 differentiated MSA-p from other groups. And all five patients with early disease stage also showed these characteristic findings.ConclusionsSWI appears to be useful for depicting putaminal hypointensity even in early stage of MSA-p. This finding suggests that iron deposition associated putaminal degeneration can occur early in the disease process.

An magnetic resonance imaging T2*‐weighted sequence at short echo time to detect putaminal hypointensity in Parkinsonisms

At 1.5 T, T2*-weighted gradient echo (GE) sequences are more sensitive in revealing mineral deposition in the basal ganglia than standard T2 weighted sequences. T2*-weighted GE sequences, however, may detect putaminal hypointensities either in patients affected by parkinsonian syndromes or in healthy subjects. The aim of this study was to identify the magnetic resonance imaging (MRI) T2*-weighted sequence which more specifically detected putaminal hypointensities differentiating atypical parkinsonian syndromes from Parkinson's disease (PD) and control subjects. In a sample of 38 healthy subjects, we performed three T2*-weighted GE sequences at increasing time echo (TE; TE = 15 millisecond, TE = 25 millisecond, and echoplanar at TE = 40 millisecond; T2* sequences study). The sequence not showing any putaminal abnormality in the healthy subjects was then used to assess putaminal signal intensity in 189 patients with PD, 20 patients with multiple system atrophy (MSA), 41 patients with progressive supranuclear palsy (PSP), and in 150 age and sex-matched control subjects. In the T2* sequences study, the T2*-weighted TE = 15 (T2*/15) did not show any putaminal abnormalities in the healthy subjects. This sequence detected putaminal hypointensities in a significantly higher proportion of patients with MSA (35%, P < 0.05) and PSP (24.4%, P < 0.05) than in patients with PD (5.3%), but in none of the controls. The sensitivity of putaminal hypointensity in T2*/15 sequence was 25.4% for PD, 43.9% for PSP, and 55% for MSA versus controls whereas the specificity was 93.2% for all groups. Despite the suboptimal sensitivity, the high specificity of the T2*/15 sequence performed on routine MRI suggests its usefulness in clinical practice for identifying putaminal hypointensities associated with parkinsonian disorders.

Multiple system atrophy

Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder of unknown etiology. It is the most frequent disorder among atypical parkinsonism with an estimated prevalence of 2 to 5 per 100 000 inhabitants. The clinical symptoms are rapidly progressing with a mean survival ranging between 6 to 9 years. The diagnosis is based on consensus criteria that have been revised in 2008. The diagnostic criteria allow defining "possible", "probable" and "definite" MSA. The latter requires post mortem confirmation of striatonigral and olivopontocerebellar degeneration with alpha-synuclein containing glial cytoplasmic inclusions. The diagnosis of "possible" and "probable" MSA is based on the variable presence and severity of parkinsonism, cerebellar dysfunction, autonomic failure and pyramidal signs. According to the revised criteria, atrophy of putamen, pons, middle cerebellar peduncle (MCP) or cerebellum on brain magnetic resonance imaging are considered to be additional features for the diagnosis of "possible" MSA. T2-weighted brain imaging may further reveal a putaminal hypointensity, a hyperintense lateral putaminal rim, the so called "hot cross bun sign" and MCP hyperintensities. Cardiovascular examination, urodynamic testing and anal sphincter electromyography may be helpful for the diagnosis of autonomic failure. Some patients may respond to levodopa, but usually to a lesser extent than those suffering from Parkinson's disease, and high doses are already required in early disease stages. No specific therapy is available for cerebellar dysfunction, while effective treatments exist for urinary and cardiovascular autonomic failure. Physical therapy may help to improve the difficulties of gait and stance, and to prevent their complications. In later disease stages, speech therapy becomes necessary for the treatment of dysarthria and dysphagia. Percutaneous gastrostomy is sometimes necessary in patients with severe dysphagia. Beyond these strategies, psychological support, social care and occupational therapy to adapt the environment to the patient's disability are prerequisites for improving the quality of life in MSA patients.

Utility of susceptibility-weighted MRI in differentiating Parkinson’s disease and atypical parkinsonism

Neuropathological studies report varying patterns of brain mineralization in Parkinson's diseases (PD), progressive supranuclear palsy (PSP), and Parkinson variant of multiple system atrophy (MSA-P). Susceptibility-weighted imaging (SWI) is the ideal magnetic resonance imaging (MRI) technique to detect mineralization of the brain. The purpose of this study was to test if SWI can differentiate PD, PSP, and MSA-P. Eleven patients with PD, 12 with PSP, 12 with MSA-P, and 11 healthy controls underwent SWI of the brain. Hypointensity of putamen, red nucleus, substantia nigra, and dentate nucleus in all groups were measured using an objective grading scale and scored from 0 to 3. In PSP, hypointensity score of red nucleus was higher than that in MSA-P (p=0.001) and PD (p=0.001), and a score of ≥ 2 differentiated the PSP group from the PD and MSA-P groups. Putaminal hypointensity score was higher in PSP when compared to that in PD (p=0.003), and a score of ≥ 2 differentiated PSP from PD groups. SWI hypointensity scores of red nucleus and putamen had an excellent intrarater and interrater correlation. Substantia nigra hypointensity score of the PSP group was higher than that of the MSA-P (p=0.004) and PD (p=0.006) groups, but the scores had only a moderate intrarater and interrater correlation. SWI shows different patterns of brain mineralization in clinically diagnosed groups of PD, PSP, and MSA-P and may be considered as an additional MR protocol to help differentiate these conditions.