Article

Diagnostic accuracy of I-123-FP-CIT SPECT in possible dementia with Lewy bodies

Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK. j.t.o'
The British journal of psychiatry: the journal of mental science (Impact Factor: 7.99). 02/2009; 194(1):34-9. DOI: 10.1192/bjp.bp.108.052050
Source: PubMed

ABSTRACT

(123)I-FP-CIT SPECT (single photon emission computed tomography) can help in the differential diagnosis of probable dementia with Lewy bodies (Lewy body dementia) and Alzheimer's disease.
Our aim was to determine the accuracy of (123)I-FP-CIT SPECT in diagnosing people with possible dementia with Lewy bodies.
We undertook a 12-month follow-up of 325 individuals with probable or possible Lewy body or non-Lewy body dementia who had previously undergone (123)I-FP-CIT SPECT. A consensus panel, masked to SPECT findings, established diagnosis at 12 months in 264 people.
Of 44 people with possible dementia with Lewy bodies at baseline, at follow-up the diagnosis for 19 people was probable dementia with Lewy bodies (43%), in 7 people non-Lewy body dementia (16%) and for 18 individuals it remained possible dementia with Lewy bodies (41%). Of the 19 who at follow-up were diagnosed with probable dementia with Lewy bodies, 12 had abnormal scans at baseline (sensitivity 63%); all 7 individuals with a possible diagnosis who were diagnosed as having Alzheimer's disease at follow-up had normal scans (specificity 100%).
Our findings confirm the diagnostic accuracy of (123)I-FP-CIT SPECT in distinguishing Lewy body from non-Lewy body dementia and also suggest a clinically useful role in diagnostically uncertain cases, as an abnormal scan in a person with possible dementia with Lewy bodies is strongly suggestive of dementia with Lewy bodies.

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    • "In addition, the compounds importance has increased as its application range has been extended to the differentiation of dementia with Lewy bodies from Alzheimer's disease (Walker et al. 2007; Colloby et al. 2008; O'Brien et al. 2009). After intravenous injection, [123I]FP-CIT SPECT binds to the dopamine transporters in the striatum. "
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    ABSTRACT: Spatial affine registration of brain images to a common template is usually performed as a preprocessing step in intersubject and intrasubject comparison studies, computeraided diagnosis, region of interest selection and brain segmentation in tomography. Nevertheless, it is not straightforward to build a template of [123I]FP-CIT SPECT brain images because they exhibit very low intensity values outside the striatum. In this work, we present a procedure to automatically build a [123I]FP-CIT SPECT template in the standard Montreal Neurological Institute (MNI) space. The proposed methodology consists of a head voxel selection using the Otsu's method, followed by a posterization of the source images to three different levels: background, head, and striatum. Analogously, we also design a posterized version of a brain image in the MNI space; subsequently, we perform a spatial affine registration of the posterized source images to this image. The intensity of the transformed images is normalized linearly, assuming that the histogram of the intensity values follows an alpha-stable distribution. Lastly, we build the [123I]FP-CIT SPECT template by means of the transformed and normalized images. The proposed methodology is a fully automatic procedure that has been shown to work accurately even when a high-resolution magnetic resonance image for each subject is not available.
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    • "Le fait qu'elle ait servi de justification principale a ` la prise en charge de l'examen par l'assurance maladie en France est assez critiquable, puisque la population de l'e ´ tude (DCL et MA probables pour l'essentiel) ne correspond pas a ` celle où l'examen a ré ellement un inté rê t. L'analyse dans le dé tail des donné es de l'article (McKeith et al., 2007), le suivi e ´ volutif des patients (O'Brien et al., 2009) et les corré lations pathologiques effectué es ulté rieurement dans une vingtaine de cas (Walker et al., 2007) montrent toutefois que le FP-CIT est anormal dans la plupart des DCL de pré sentation atypique (y compris celles sans syndrome parkinsonien). En outre, trois cas de dé mence mixte MA-DCL confirmé s a ` l'autopsie, dont deux avaient une pré sentation clinique non-DCL, avaient une scintigraphie au FP-CIT positive (Walker et al., 2007). "
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    ABSTRACT: Dementia with Lewy bodies (DLB) is the second cause of degenerative dementia in autopsy studies. In clinical pratice however, the prevalence of DLB is much lower with important intercenter variations. Among the reasons for this low sensitivity of DLB diagnosis are (1) the imprecision and subjectivity of the diagnostic criteria; (2) the underestimation of non-motor symptoms (REM-sleep behavior disorder, dysautonomia, anosmia); mostly (3) the nearly constant association of Lewy bodies with Alzheimer's disease pathology, which dominates the clinical phenotype. With the avenue of targeted therapies against the protein agregates, new clinical scales able to apprehend the coexistence of Lewy pathology in Alzheimer's disease are expected.
    Full-text · Article · Nov 2013 · Revue Neurologique
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    • "Probable DLB refers to a clinical syndrome that has been well validated against autopsy and has a high positive predictive value (>75%) (Litvan et al. 2003). Possible DLB is a more uncertain category, with the positive predictive value less clearly established but more likely to be 450% (O'Brien et al. 2009). The aims of the current study were to (i) provide an updated review including all recently published prevalence and incidence studies; (ii) examine the impact of the introduction of the new DLB diagnostic criteria on prevalence rates; and (iii) compare prevalence estimates from population samples to those from clinical settings. "
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    ABSTRACT: Background: Dementia with Lewy bodies (DLB) is increasingly recognized as a common cause of dementia in older people. However, its true frequency remains unclear, with previous studies reporting a prevalence range from zero to 22.8% of all dementia cases. This review aimed to establish the population prevalence and incidence for DLB and to compare this to its prevalence in secondary care settings. Method: A literature review of all relevant population and clinical studies was conducted using PubMed. Additional references from papers found during that process were added to this. Results: DLB accounted for 4.2% of all diagnosed dementias in the community. In secondary care this increased to 7.5%. The incidence of DLB was 3.8% of new dementia cases. There was a significant increase in DLB diagnoses when using the revised (2005) International Consensus Criteria (ICC) for DLB compared to the original (1996) criteria. Conclusions: DLB currently accounts for around one in 25 dementia cases diagnosed in the community and one in 13 cases in secondary care. The significantly higher rates of DLB in secondary care may reflect enhanced diagnostic accuracy in specialist settings and/or the increased morbidity and carer burden of the DLB syndrome compared to other dementias. However, the true prevalence is likely to be much higher because DLB diagnoses are often missed, although there is evidence that new criteria aid case identification.
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