technetium-tc-99m-exametazime and 2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane

The aim of this study was to investigate the diagnostic value of occipital lobe and posterior cingulate perfusion in predicting dopamine transporter imaging outcome using a quantitative measure of analysis.. In total, 99 patients with cognitive complaints who had undergone both technetium-99m-hexamethylpropyleneamine oxime single-photon emission computed tomography (Tc-HMPAO SPECT) and I ioflupane (I-FP-CIT also called DaTSCAN) imaging in a dementia diagnostic center were analyzed. Measures of perfusion were calculated from HMPAO SPECT images for the medial and lateral occipital lobe, the posterior cingulate cortex, precuneus and cuneus regions of interest using statistical parametric mapping 8. DaTSCAN images were quantified and specific binding ratios were calculated independent from HMPAO SPECT results. Statistical parametric mapping and tests of associations between perfusion and I-FP-CIT imaging were completed.. Regions of interest on HMPAO yielded poor predictive values when used independently to predict I-FP-CIT status; however, the combination of normal posterior cingulate perfusion with medial and lateral occipital hypoperfusion was associated significantly with I-FP-CIT status, χ (1, N=99)=9.72, P=0.002. This combination also yielded a high positive likelihood ratio and specificity (11.1, 98%). Sensitivity was, however, low (22%). No significant perfusion differences were found when abnormal and normal I-FP-CIT groups were compared directly using voxel-based morphometry (P<0.05, family-wise error).. The combination of medial and lateral occipital hypoperfusion with preserved posterior cingulate gyrus perfusion is highly specific for individuals with a positive I-FP-CIT scan in a clinical sample where diagnostic doubt exists. This regional combination, however, lacks sensitivity; therefore, absence of the sign cannot be used to rule out dementia with Lewy bodies. A positive finding provides strong evidence to rule in dementia with Lewy bodies.

Topics: Aged; Cerebrovascular Circulation; Female; Gyrus Cinguli; Humans; Lewy Body Disease; Male; Occipital Lobe; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tropanes

Molecular brain imaging I-FP-CIT SPECT is an important tool in evaluation of patients with parkinsonism. However, various neurodegenerative etiologies cannot be differentiated by I-FP-CIT SPECT alone. We present a case of progressive supranuclear palsy with abnormal I-FP-CIT SPECT and abnormal Tc-HMPAO SPECT depicted by quantitative analyses but unremarkable MRI 16 months after the onset of symptoms. Brain autopsy demonstrated presence of neuronal and glial tau pathology in both cortical and subcortical regions confirming the diagnosis of progressive supranuclear palsy. This case illustrates potential values of multimodal molecular brain imaging in conjunction with quantitative analysis in the evaluation of movement disorders.

Topics: Female; Humans; Middle Aged; Radiopharmaceuticals; Supranuclear Palsy, Progressive; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tropanes

The aim of this study is to investigate the diagnostic value of perfusion 99mTc-exametazime single photon emission computed tomography (SPECT) in the diagnosis of dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) in comparison with dopaminergic 123I-2beta-carbomethoxy-3beta-(4-iodophenyl)-n-(3-fluoropropyl) nortropane (FP-CIT) SPECT imaging.. Subjects underwent 99mTc-exametazime scanning (39 controls, 36 AD, 30 DLB) and 123I-FP-CIT scanning (33 controls, 33 AD, 28 DLB). For each scan, five raters performed visual assessments blind to clinical diagnosis on selected transverse 99mTc-exametazime images in standard stereotactic space. Diagnostic accuracy of 99mTc-exametazime was compared to 123I-FP-CIT results for the clinically relevant subgroups AD and DLB using receiver operating characteristic (ROC) curve analysis.. Inter-rater agreement for categorizing uptake was "moderate" (mean kappa = 0.53) for 99mTc-exametazime and "excellent" (mean kappa = 0.88) for 123I-FP-CIT. For AD and DLB, consensus rating matched clinical diagnosis in 56% of cases using 99mTc-exametazime and 84% using 123I-FP-CIT. In distinguishing AD from DLB, ROC analysis revealed superior diagnostic accuracy with 123I-FP-CIT (ROC curve area 0.83, sensitivity 78.6%, specificity 87.9%) compared to occipital 99mTc-exametazime (ROC curve area 0.64, sensitivity 64.3%, specificity 63.6%) p = 0.03.. Diagnostic accuracy was superior with 123I-FP-CIT compared to 99mTc-exametazime in the differentiation of DLB from AD.

Topics: Aged; Alzheimer Disease; Control Groups; Diagnosis, Differential; Dopamine; Female; Humans; Iodine Radioisotopes; Lewy Body Disease; Male; Neurofibrillary Tangles; Occipital Lobe; Regional Blood Flow; ROC Curve; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Tropanes

This protocol presents an improved method for SPECT imaging based on multi-pinhole techniques, applied to the visualisation of neurotracers in small animal models. Three types of collimators with 6-pinhole apertures adapted to special requirements for the imaging of the brain of mice and rats and to full body imaging in mice are employed in the experiments. A conventional triple-headed TRIAD/Trionix SPECT system was upgraded with pyramidal supports and shieldings onto the multi-pinhole collimators were installed. The system was employed for the assessment of the uptake of [123I]FP-CIT and [123I]IBZM, well known tracers of dopamine transport and dopamine D2/D3 receptors, respectively. Requirements regarding the applied radioactivity are reported, as well as further conditions determining the effectiveness of the detection of the uptake of [123I]FP-CIT and [123I]IBZM. The measurements in mice required only 20-25% of the activity described in previous studies. Dynamic measurements are presented, with a time resolution as high as 10 min in the brain of rats. Due to the lower signal intensity obtained for mice, the time resolution was 42min for [123I]FP-CIT, with a ratio ROI/background of 5.4, and 17 min for [123I]IBZM, with the ratio ROI/background of 4.5 (1.6-7.4).

Topics: Anesthesia; Animals; Benzamides; Brain; Iodine Radioisotopes; Magnetic Resonance Imaging; Mice; Organotechnetium Compounds; Pyrrolidines; Radiopharmaceuticals; Rats; Rats, Inbred WKY; Reference Standards; Technetium Tc 99m Exametazime; Thyroid Gland; Tomography, Emission-Computed, Single-Photon; Tropanes

To assess the role of 99mTc-hexamethylpropyleneamine oxime single-photon emission computed tomography (99mTc-HMPAO SPECT) imaging of the precuneus and medial temporal lobe in the individual patient with mild Alzheimer's disease and dementia with Lewy bodies (DLB) using statistical parametric mapping and visual image interpretation.. Thirty-four patients with mild late-onset Alzheimer's disease, 20 patients with early-onset Alzheimer's disease, 15 patients with DLB and 31 healthy controls were studied. All patients fulfilled appropriate clinical criteria; the DLB patients also had evidence of dopaminergic presynaptic terminal loss on 123I-N-omega-fluoropropyl-2beta-carbomethoxy-3beta-(4-iodophenyl)-tropane imaging. 99mTc-HMPAO SPECT brain scans were acquired on a multidetector gamma camera and images were assessed separately by visual interpretation and with SPM99.. Statistical parametric maps were significantly more accurate than visual image interpretation in all disease categories. In patients with mild late-onset Alzheimer's disease, statistical parametric mapping demonstrated significant hypoperfusion to the precuneus in 59% and to the medial temporal lobe in 53%. Seventy-six per cent of these patients had a defect in either location. No controls had precuneal or medial temporal lobe hypoperfusion (specificity, 100%). Statistical parametric mapping also demonstrated 73% of patients with DLB to have precuneal abnormalities, but only 6% had medial temporal lobe involvement.. These findings illustrate the capability of statistical parametric mapping to demonstrate reliable abnormalities in the majority, but not all, patients with either mild Alzheimer's disease or DLB. Precuneal hypoperfusion is not specific to Alzheimer's disease and is equally likely to be found in DLB. In this study, medial temporal hypoperfusion was significantly more common in Alzheimer's disease than in DLB. Statistical parametric maps appear to be considerably more reliable than simple visual interpretation of 99mTc-HMPAO images for these regions.

Topics: Adult; Aged; Aged, 80 and over; Alzheimer Disease; Brain; Brain Mapping; Case-Control Studies; Cerebral Cortex; Computational Biology; Data Interpretation, Statistical; Female; Humans; Iodine Radioisotopes; Lewy Body Disease; Male; Middle Aged; Models, Statistical; Perfusion; Software; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Tropanes