Search

Although the diagnosis of Parkinson's disease (PD) is essentially clinical, the implementation of imaging techniques can improve diagnostic accuracy. While some techniques (e.g. magnetic resonance imaging-MRI, computerized tomography-CT) are used to exclude secondary syndromes, presynaptic dopaminergic imaging including imaging of dopamine transporter (DAT)-can help the Neurologist in the differential diagnosis between neurodegenerative parkinsonian syndromes and parkinsonism without dopamine deficiency. DAT imaging can be useful in cases in which the clinical picture is not univocal, as in case of overlapping clinical features in patients with early disease, atypical syndromes or unsatisfying response to therapy. Currently, ( 123 I)FP-CIT ([123I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane) (trade name DaTSCAN) is the only agent approved by international regulatory agencies for this purpose. With the increasing use of this technique, some unexpected findings have been reported, including patients clinically diagnosed with PD with a normal SPECT scan [e.g. Scans Without Evidence of Dopaminergic Deficit (SWEDD)]; PD patients with a greater dopaminergic deficit in the striatum ipsilateral to the clinically more affected side [e.g. Scans With Ipsilateral Dopaminergic Deficit (SWIDD)]; as well as some artifacts. Moreover, the neurologist must remember that structural lesions and administration of some drugs might alter the result of DAT imaging. Unexpected findings, artifacts, and misinterpretation of imaging findings can lead to an erroneous diagnosis and inappropriate therapy, neglect of other medical conditions that might explain the clinical picture, and undermine the selection phase in clinical trials. The aim of the present review is to bring clarity on these controversial (and sometimes erroneous) results, in order to inform of these possibilities the clinicians requesting a DaTSCAN in clinical practice., (© 2021. Springer-Verlag GmbH Germany, part of Springer Nature.)

Current quantification methods of 123 I-FP-CIT SPECT rely on anatomical parcellation of the striatum. We propose here to implement a new method based on MRI segmentation and functional atlas of the basal ganglia (MR-ATLAS) that could provide a reliable quantification within the sensorimotor, associative, and limbic territories of the striatum. Patients with Parkinson's disease (PD), idiopathic rapid eye movement sleep behavioral disorder (iRBD), and healthy controls underwent 123 I-FP-CIT SPECT, MRI, motor, and cognitive assessments. SPECT data were corrected for partial volume effects and registered to a functional atlas of the striatum to allow quantification in every functional region of the striatum (nucleus accumbens, limbic, associative, and sensorimotor parts of the striatum). The MR-ATLAS quantification method is proved to be reliable in every territory of the striatum. In addition, good correlations were found between cognitive dysexecutive tests and the binding within the functional (limbic) territories of the striatum using the MR-ATLAS method, slightly better than correlations found using the anatomical quantification method. This new MR-ATLAS method provides a robust and useful tool for studying the dopaminergic system in PD, particularly with respect to cognitive functions. It may also be relevant to further unravel the relationship between dopaminergic denervation and cognitive or behavioral symptoms., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Holmes's tremor (HT) is assumed to be the result of coexistence of nigrostriatal dopaminergic system impairment and the lesion of cerebello-thalamic pathways. It was suggested that dopaminergic deficiency is responsible for rest tremor, and lack of compensatory cerebellar function leads to spill of tremor into voluntary movements. Cases of HT with and without abnormalities of the presynaptic part of dopaminergic nigrostriatal were published and these findings raised the question of possibility of the postsynaptic lesion. Three patients with HT diagnosed according to criteria of Consensus Statement on Tremor were studied. In all of them SPECT imaging with ligands of presynaptic (I 123-FP CIT-DaTSCAN) and postsynaptic (I 123-iodobenzamide-IBZM) nigrostriatal dopaminergic neurons was performed. Indices of uptake in caudate and putamen normalized to nonspecific uptake in occipital cortex and indices of asymmetry for each whole striatum as well as for putamen and caudate separately were calculated. SPECT studies did not reveal asymmetry of DaTSCAN and IBZM binding in striatum in all studied subjects. The current clinical diagnostic criteria of HT are presumably insufficiently specific and when using them we identify patients both with and without the involvement of dopaminergic system. These two groups may represent tremor disorders of similar phenomenology but of different pathomechanism.

Background: We previously reported on a cohort of dystonic tremor and patients with scans without evidence of dopaminergic deficit (SWEDDs). We aim to report the long-term clinical and imaging follow-up of these patients., Patients and Methods: Patients with at least 5-year follow-up were included. These patients had an asymmetric arm tremor, a previous diagnosis of Parkinson's disease (PD), and a subsequent normal DaTscan. The imaging and clinical follow-up was done on the clinical basis., Results: Sixteen patients were included. The mean gap between the first and subsequent scans was 5.4 years. Two patients (12.5%) had reduced nigrostriatal uptake on follow-up DaTscan, whereas 14 continued to have normal dopaminergic imaging., Conclusion: This is the longest follow up of patients with asymmetric rest tremor and normal DaT scans (SWEDDs) reported to date. We show here that only a minority of them show reduced striatonigral uptake over long term follow up., (© 2014 International Parkinson and Movement Disorder Society.)

Background: Genetic risk factors impact around 15% of Parkinson's disease (PD) patients and at least 23 variants have been identified including Glucocerebrosidase (GBA) gene variants. Using different clinical and instrumental qualitative‐based data, various studies have been published on GBA‐PD cohorts which suggested possible differences in dopaminergic nigrostriatal denervation pattern, particularly in caudate and putamen nuclei. Methods: This retrospective study included two consecutive homogenous cohorts of GBA‐PD and idiopathic (I‐PD) patients. Each consecutive GBA‐PD patient has been matched with a 1:1 pairing method with a consecutive I‐PD subject according to age, age at disease onset, sex, Hoehn & Yahr (H&Y) staging scale and comorbidity level (CCI). Semiquantitative volumetric data by the DaTQUANTTM software integrated in the DaTSCAN exam performed at time of the diagnosis (SPECT imaging performed according to current guidelines of I‐123 FPCIT SPECT imaging) were extrapolated. Bilateral specific binding ratios (SBR) at putamen and caudate levels were calculated, using the occipital lobes uptake. The Mann–Whitney test was performed to compare the two cohorts while the Spearman's test was used to find correlations between motor and volumetric data in each group. Bonferroni correction was used to account for multiple comparisons. Results: Two cohorts of 25 patients each (GBA‐PD and I‐PD), were included. By comparing GBA‐PD and I‐PD patients, lower SBR values were found in the most affected anterior putamen and left caudate of the GBA‐PD cohort. Furthermore, in the GBA‐PD cohort the SBR of the most affected posterior putamen negatively correlated with the H&Y scale. However, none of these differences or correlations remained significant after Bonferroni correction for multiple comparisons. Conclusions: We observed differences in SBR values in GBA‐PD patients compared with I‐PD. However, these differences were no longer significant after Bonferroni multiple comparisons correction highlighting the need for larger, longitudinal studies. [ABSTRACT FROM AUTHOR]

Background: Dopamine transporter (DAT) imaging of striatum is clinically used in Parkinson's disease (PD) and neurodegenerative parkinsonian syndromes (PS) especially in the early disease stages. The aim of the present study was to evaluate the diagnostic performance of the recently developed tracer for DAT imaging [18F]FE-PE2I PET/CT to the reference standard [123I]FP-CIT SPECT. Methods: Ninety-eight unselected patients referred for DAT imaging were included prospectively and consecutively and evaluated with [18F]FE-PE2I PET/CT and [123I]FP-CIT SPECT on two separate days. PET and SPECT scans were categorized independently by two blinded expert readers as either normal, vascular changes, or mixed. Semiquantitative values were obtained for each modality and compared regarding effect size using Glass' delta. Results: Fifty-six of the [123I]FP-CIT SPECT scans were considered abnormal (52 caused by PS, 4 by infarctions). Using [18F]FE-PE2I PET/CT, 95 of the 98 patients were categorized identically to SPECT as PS or non-PS with a sensitivity of 0.94 [0.84–0.99] and a specificity of 1.00 [0.92–1.00]. Inter-reader agreement for [18F]FE-PE2I PET with a kappa of 0.97 [0.89–1.00] was comparable to the agreement for [123I]FP-CIT SPECT of 0.96 [0.76–1.00]. Semiquantitative values for short 10-min reconstructions of [18F]FE-PE2I PET/CT were comparable to longer reconstructions. The effect size for putamen/caudate nucleus ratio was significantly increased using PET compared to SPECT. Conclusions: The high correspondence of [18F]FE-PE2I PET compared to reference standard [123I]FP-CIT SPECT establishes [18F]FE-PE2I PET as a feasible PET tracer for clinical use with favourable scan logistics. [ABSTRACT FROM AUTHOR]

Objectives: Bipolar disorder (BD) has been suggested to be a risk factor for the development of Parkinson's disease (PD). Standard treatment of BD includes drugs that are known to induce drug-induced parkinsonism (DIP). Clinical differentiation between PD and DIP is crucial and might be aided by functional neuroimaging of the dopaminergic nigrostriatal pathway. Methods: Twenty consecutive BD patients with parkinsonism were clinically assessed and underwent 123I-ioflupane dopamine transporter single-photon emission computer tomography (SPECT). Imaging data of BD patients with pathological scans were further compared to a population of 40 de novo PD patients. Results: Four BD patients had abnormal scans, but their clinical features and cumulative exposure to both antipsychotic drugs and lithium were similar to those of BD patients with normal dopamine transporter imaging. BD patients with pathological scans had putaminal binding ratio and putamen-to-caudate ratios higher than those of PD patients despite a similar motor symptom burden. Conclusions: Up to 20% of BD patients with parkinsonism might have an underlying dopaminergic deficit, which would not be due to cumulative exposure to offending drugs and is ostensibly higher than expected in the general population. This supports the evidence that BD represents a risk factor for subsequent development of neurodegenerative parkinsonism, the nature of which needs to be elucidated. [ABSTRACT FROM AUTHOR]

Highlights • A method of same day dual isotope FP-CIT and HMPAO SPECT imaging is proposed. • Planar and SPECT phantom studies were conducted to evaluate the method. • Comparable levels of both contrast and resolution were achieved. • A proof of concept has been provided for same day imaging. Abstract When cognitive impairment is first evident it can be difficult to distinguish between different conditions such as idiopathic Parkinson's disease and Lewy body dementia. Imaging both cerebral perfusion and dopamine transporter function has been shown to provide accurate differentiation between the most common conditions. At present cerebral perfusion and dopamine transporter imaging is conducted on separate days. Carrying out both scans on the same day has the potential to benefit the patient through the social convenience of one visit to hospital and the earlier availability of results. This work considered whether it was possible to obtain diagnostic quality images from Ioflupane (123I) single positron emission tomography (SPECT) acquired at the same time as or four hours after a Exametazime (99mTc) SPECT on the same day. Possible changes to the Ioflupane (123I) SPECT acquisition and processing protocols such as a new energy window and use of a resolution recovery algorithm were explored using phantom studies. Initial phantom results show that when a four hour delay between acquisitions is used comparable contrast to noise ratios can be achieved (4.23 vs. 4.63) with an insignificant loss in resolution (11.51 mm vs. 11.35 mm full width at half maximum (FWHM)). An offset energy window (159 keV −5.5% & +15.5%) was found to provide the highest contrast to noise ratio. This work provides a proof of concept for same day imaging. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Background and Purpose: Computer-based analysis of Dopamine transporter imaging (DaTscan) can aid in image interpretation. In this study, we examined the distribution of putamen-to-caudate ratios (PCRs) obtained by using a clinically available semiquantification method.Methods: Medical records of 32 patients (M:16) with a diagnosis of Parkinson's disease (PD) (n = 22) or Parkinson's plus syndromes (PPS) (n = 10) based on clinical follow-up, were retrospectively reviewed. Single photon emission tomography (SPECT) imaging was performed 4 hours after intravenous injection of 3-5 mCi [I-123]-ioflupane. Semiquantitative evaluation using DaTQUANT software was performed. Utility of PCR with a cutoff of .7 and .8 in the diagnosis of nigrostriatal degeneration was assessed. PD and PPS groups based on clinical assessment and caudate-to-background ratio (CBR) were assessed separately.Results: Minimum PCR for both hemispheres was .74 ± .09 (Mean ± SD, range: .58-.89), with 65.63% patients (21/32) having PCR > .7. Mean PCR in mild nigrostriatal degeneration was .77 ± .08 (range: .62-.89) and in advanced nigrostriatal degeneration was .73 ± .09 (range: .58-.89). Mean PCR in PD group was .73 ± .09 (range: .58-.89) and in PPS group was .75 ± .10 (range: .61-.88).Conclusions: Although PCR can intrinsically be a useful indication of disease, this ratio obtained in our analysis by using one of the clinically available automatic semiquantitative methods has large variability and might not be a reliable numeric marker in interpretation of [I-123]ioflupane studies. This may be due to difficulty in separating caudate from putamen on SPECT images, as well as the nonuniform decreased Ioflupane uptake in both putamen and caudate. [ABSTRACT FROM AUTHOR]

Purpose: We developed a new analytical method to quantify the dopamine transporter (DAT) radiation dose in the striatum on [123I] FP-CIT single-photon emission computed tomography (SPECT). This method is based on the dopamine transporter standardized uptake value (DaTSUV). The purpose of this study was to compare DaTSUV with the classical specific binding ratio (SBR) in the discrimination of dopaminergic neurodegenerative diseases (dNDD) from non-dNDD.Method: Seventy-seven consecutive patients who underwent DaTscan were included. Patients were divided into a dNDD group (n = 44; 24 men, 20 women; median age 73 years) and a non-dNDD group (n = 33; 14 men, 19 women; median age 75 years) based on their clinical diagnoses. The relationship between each method was evaluated by Pearson's correlation coefficient. Differences in SBR and DaTSUV in each group were evaluated by t test. Pairwise comparison of receiver operating characteristic (ROC) curve analysis was performed to compare the discriminating abilities of each method according to the standard error of the area under the curve (AUC). A value of p < 0.05 was considered statistically significant.Result: There was a significant strong correlation between DaTSUV and SBR (r = 0.910 [95% CI = 0.862-0.942], p < 0.001). The dNDD group showed significantly lower SBR (3.48 [1.25-7.91] vs 6.58 [3.81-11.1], p < 0.001) and DaTSUV (4.91 [1.59-13.6] vs 8.61 [2.29-15.6], p < 0.001) than the non-dNDD group. The discriminating ability of SBR (AUC = 0.918) was significantly higher than that of DaTSUV (AUC = 0.838, p = 0.0176).Conclusion: DaTSUV has a good correlation with SBR, but it could not exceed SBR for discriminating dNDD from non-dNDD. [ABSTRACT FROM AUTHOR]

Retinis pigmentosa is a form of retinal dystrophy characterized by pigment deposition resulting in loss of peripheral vision, tunnel vision, night blindness and in some cases full blindness. Parkinson's disease is a progressive extrapyramidal neurological disorder characterized by rigidity, bradykinesia and tremor at rest due to loss of substantia nigra's dopaminergic cell; this loss can be evaluated with [123I]Ioflupane single-photon emission computed tomography (SPECT). There are growing evidences underlying a possible correlation between these two conditions; in this report we describe a patient affected by retinitis pigmentosa with a positive [123I]Ioflupane scan underlying a possible connection with Parkinson's disease. [ABSTRACT FROM AUTHOR]

Background: Parkinson's disease (PD) is among the most prevalent neurodegenerative conditions. While motor and nonmotor aspects of this disease have been well characterized, no objective biomarker exists to support an accurate clinical diagnosis. However, newer imaging techniques, including [123I]-FP-CIT (DaTSCAN), have demonstrated utility in differentiating between PD and non-neurodegenerative tremor disorders. Objective: DaTSCAN has been primarily investigated in situations where diagnostic confusion exists, and in these instances has been shown to significantly impact clinical management. The goal of this pilot study was to evaluate the impact of DaTSCAN on the clinical management of patients with early probable PD, where no diagnostic uncertainty exists. Methods: Thiswas a prospective, 54-week, comparative pilot study, in which twenty subjects with de novo PD were randomly assigned to DaTSCAN either immediately upon diagnosis (and again at 6 and 12 months) or delayed to 6 months (and again at 12 months). The primary outcome measure was the frequency of deviation from the initial treatment plan from baseline to 54 weeks between the two groups. Secondary outcomes included motor and non-motor assessments. Results: There was no significant difference in the number of treatment changes over the course of the study between the two groups: initial imaging group = 4.2 (SD:2.74) vs. delayed imaging group = 2.3 (SD:2.0, p = 0.11). In addition, there were no group differences in medication requirements, motor performance, or patient expectations of disease. Conclusions: In patients with early, probable PD, DaTSCAN contributes no additional impact on clinical management or functional outcomes when added to the diagnostic algorithm. [ABSTRACT FROM AUTHOR]

Introduction: Dopamine transporter imaging with (123)I-FP-CIT single photon emission computed tomography (SPECT) is helpful for the differential diagnosis between Parkinsonian syndrome (PS) and essential tremor (ET). Although visual assessment and time-consuming manual evaluation techniques are readily available, a fully objective and automated dopamine transporter quantification technique is always preferable, at least in research and follow-up investigations. Our aim was to develop a novel automated magnetic resonance imaging (MRI)-based evaluation technique of dopamine transporter SPECT images and to compare its diagnostic accuracy with those of the gold-standard visual grading and manual dopamine transporter binding quantification methods.Methods: (123)I-FP-CIT SPECT and MRI sessions were conducted in 33 patients with PS (15 men; mean age: 60.3 ± 9.7 years) and 15 patients with ET (8 men; mean age: 54.7 ± 16.3 years). Striatal dopamine transporter binding was visually classified by 2 independent experts as normal or abnormal grade I, II and III. Caudal and putaminal specific uptake ratios were calculated by both automated MRI-based and manual evaluation techniques.Results: We found almost perfect agreement (κ = 0.829) between the visual scores by the 2 observers. The automated method showed strong correlation with the visual and manual evaluation techniques and its diagnostic accuracy (sensitivity = 97.0%; specificity = 93.3%) was also comparable to these methods. The automatically determined uptake parameters showed negative correlation with the clinical severity of parkinsonism. Based on ordinal regression modelling, the automated MRI-based method could reliably determine the visual grading scores.Conclusion: The novel MRI-based evaluation of (123)I-FP-CIT SPECT images is useful for the differentiation of PS from ET. [ABSTRACT FROM AUTHOR]

Background: The objective of this study was to study motor and nonmotor symptoms and striatal dopaminergic denervation, as well as the relationship between them, in a cohort of asymptomatic relatives of patients with Parkinson's disease (PD) with the R1441G-leucine-rich repeat kinase 2 mutation. Methods: Asymptomatic relatives of patients with PD and this mutation were tested for the presence of the mutation and evaluated for striatal, putamenal, and caudate dopaminergic transporters using (123)I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)-nortropane single-photon emission computed tomography binding ratios. Clinical and neuropsychological evaluations including timed motor tests, a smell identification test, and global cognition, attention, executive, visuospatial, and memory functions as well as depression, constipation, and rapid eye movement sleep behavior disorder were also assessed. Results: Twenty-seven carriers and 19 noncarriers were studied. Compared with noncarriers, mutation carriers had significantly lower (123)I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)-nortropan mean striatal (P = 0.03), mean putamenal (P = 0.01), and lowest putamenal (P = 0.01) binding ratios. Multiple linear regression analysis showed that the carrier status and the execution of timed tests significantly predicted striatal (123)I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)-nortropane binding. The proportion of variation accounted for by the regression model of these variables was 69% for the putamen and 53% for the caudate nucleus. Conclusions: Asymptomatic carriers of the R1441G-leucine-rich repeat kinase 2 mutation have evidence of dopaminergic nigrostriatal denervation, mainly in the putamen, which is associated with a decline in the execution of complex motor tests. These tests could be early indicators of the ongoing dopaminergic deficit in this group at risk of PD. [ABSTRACT FROM AUTHOR]

[I]-FP-CIT is a single photon emission computed tomography (SPECT) ligand showing in vivo the loss of dopaminergic terminals in the brain and is now available in the market. Despite several systematic studies in clinically inconclusive cases, the use of such imaging in clinical routine is scarcely reported. We analyzed 516 files of subjects with movement disorders who were consecutively examined using [I]-FP-CIT scan and determined whether the use of imaging was appropriate and if it improved clinical diagnosis or care of the patient. In addition, we determined if appropriate use was related to subspecialties in Neurology, e.g., movement disorders' specialists vs. general neurologists, and if appropriate use was increasing over time. Among the 516 scans, 18 % were in agreement with the license, 62 % were classified as appropriate and 37 % were considered inappropriate. A change of management was obvious in 60 % of patients, but in 92 % of those with an appropriate request vs. 13 % of patients with an inappropriate request. Movement disorders' specialists had more appropriate requests than other practitioners. Eventually, comparing the first 100 vs. the last 100 quantified SPECT, performed more than 2.5 years apart, we found no difference for the appropriateness of the examination. The use of [I]-FP-CIT imaging in clinical routine does not fit a restrictive license. An inappropriate use is seen in nearly 40 % of cases, which reduces the real cost-effectiveness of the technique suggesting a need for continuing medical education on the topic. [ABSTRACT FROM AUTHOR]

Objective: Analyze indications for ordering DAT-SPECT scans and the clinical impact of scan results on patients evaluated in a movement disorders practice. Background: DAT-SPECT is FDA approved to evaluate cases of suspected presynaptic dopaminergic deficiency. Little data is available on clinical use and impact of these scans among movement disorders neurologists. Methods: DAT-SPECT scans ordered at the Northwestern University Parkinson's disease (PD) and movement disorders center from 2011-2013 were reviewed. Clinic notes were reviewed for information regarding the indication for ordering each scan, and to assess for any changes in clinical impression or management choices that followed the scan. Results: 83 scans were ordered by four specialists. Scans were commonly ordered to differentiate PD from Essential Tremor (21.7%, n = 18) or from drug-induced parkinsonism (21.7%, n = 18). In 59% (n = 49) of cases, a change in clinical diagnosis or medication regimen occurred within one visit after the scan. The strongest impact was seen for the indication of ET vs. PD in which 72.2% (n = 13) had a change in diagnosis, management, or both. Conclusions: Diagnostic uncertainty in cases of parkinsonism exists even in a tertiary referral center. DAT-SPECT has significant impact on clinical diagnosis and management even in the hands of movement disorders specialists. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Parkinsonian Syndromes are difficult to accurately diagnose and distinguish from other neurological processes such as essential tremor. Until now, physical exam and clinical presentation have been the gold standard for diagnosis (bradykinesia, tremor, rigidity, and postural instability).1 However, this leads to over- or under diagnosis and improper treatment due to variability in presentation and symptoms. A nuclear medicine study using I-123 Ioflupane (DaTSCAN) has been developed, which allows accurate differentiation of Parkinsonian Syndromes from other etiologies.1 This study is now widely performed on the mainland, but has never been done in Hawai'i due to its East Coast sourcing and relatively short physical half-life. Through a highly coordinated logistical effort, Tripler Army Medical Center's Nuclear Medicine Department conducted the first DaTSCAN in Hawai'i in April 2016. [ABSTRACT FROM AUTHOR]

ABSTRACT OBJECTIVE To review [123I]FP-CIT (Ioflupane I 123, DaTscan) SPECT imaging and its role in clinical practice. BACKGROUND [123I]FP-CIT is a radiopharmaceutical that binds reversibly to striatal presynaptic dopamine transporters. METHODS We review the two principal multicenter clinical trials of [123I]FP-CIT SPECT imaging and provide additional, previously unreported information. Study 1 was a trial of [123I]FP-CIT SPECT in patients with early suspected parkinsonism that compared baseline scans to the consensus clinical diagnosis established 3 years later. Study 2 was a trial of [123I]FP-CIT SPECT in patients with established diagnoses of parkinsonian syndrome (PS) or essential tremor (ET). RESULTS In Study 1, positive percent agreement (abnormal baseline scan and clinical diagnosis of PS at 36 months [ n= 71]) was 78-79%. Negative percent agreement (normal baseline scan and a clinical diagnosis of non-PS at 36 months [ n= 28]) was 97%. In study 2, positive percent agreement (abnormal scan and a clinical diagnosis of PS [ n= 158]) was 92-97%. Negative percent agreement (normal scan and a clinical diagnosis of ET [ n= 27]) was 74-96%. CONCLUSION [123I]FP-CIT SPECT brain imaging is used to assist in the evaluation of adult patients with suspected PS and may help differentiate ET from PS as an adjunct to other diagnostic evaluations. [ABSTRACT FROM AUTHOR]

In strict application of clinical criteria of Parkinson's disease, clinical diagnosis corresponds to histopathological diagnosis in 93 % of cases. Retrospective studies show that a significant number of parkinsonian patients do not receive a distinct clinical diagnosis for at least 5 years. Errors in clinical diagnosis of Parkinson's disease account for about 10-25% of patients. Ioflupane I-123 is indicated for detecting loss of functional dopaminergic neuron terminals in the striatum when clinical symptoms such as tremor, postural instability and muscle rigidity occur. Ioflupane I-123 (DaTSCAN) binds to the presynaptic dopamine transporters and shows the integrity of the dopaminergic nigrostriatal neurons. As a result, in patients with clinically uncertain parkinsonian syndromes, Ioflupane I-123 SPECT is used to differentiate essential tremor from parkinsonian syndromes and dementia with Lewy bodies from Alzheimer's Disease. This method is also used in clinical trials with Huntington's disease, depression with anhedonia and other diseases. [ABSTRACT FROM AUTHOR]

The article discusses the significant role of dopamine transporter (DAT) imaging for early diagnosis of Parkinson's disease. It highlights the results of the report made by Susanna Jacobson and colleagues of DAT imaging with single-photon emission computed tomography in Parkinsonian patients comparing visual and semi-quantitative assessment. It reveals that discrepancy exists between imaging and clinical observation of Parkinsonism.