Search

Objectives: We aimed to evaluate correlations between striatal dopamine transporter (DAT) uptake and clinical assessments in both patients with Parkinson's disease (PD) and healthy controls. Methods: This study enrolled 193 healthy controls, and 581 patients with PD. They underwent various clinical assessments and 123I-FP-CIT SPECT scans. After reconstruction, attenuation correction, and normalization of SPECT images, counts were measured from the bilateral caudate and putamen, and the occipital cortex for reference. Count densities for each region were extracted and used to calculate striatal binding ratios (SBRs) for each striatal region. SBR is calculated as (target region/reference region)—1. After logarithmic transformation of striatal SBRs, we analyzed the effects of clinical assessments on striatal SBRs using Bayesian hierarchical modeling. Results: MDS-UPDRS total score, part I, part II, part III, Epworth Sleepiness Scale, REM sleep behavior disorder screening questionnaire, SCOPA-AUT total score were negatively associated with striatal SBR in patients with PD. Also, HVLT recognition discrimination was positively associated with striatal SBR in both healthy controls and patients with PD. In healthy control, MDS-UPDRS part II, MOCA, SCOPA-AUT total score were positively associated with striatal SBR. Conclusion: We demonstrated that motor symptom, sleep disturbance, autonomic symptom, and cognition of patients with PD were associated with striatal dopaminergic activity. In healthy controls, motor symptoms, autonomic symptom, and cognition were associated with striatal dopaminergic activity, some of which showing the opposite direction with patients with PD. This result might provide new insight to underlying mechanism of dopamine system with motor and non-motor assessments. [ABSTRACT FROM AUTHOR]

To identify the optimal scattering correction for 123I-FP-CIT SPECT (DAT-SPECT) using a two-detector whole-body cadmium–zinc–telluride semiconductor detector (C-SPECT) system with a medium-energy high-resolution sensitivity (MEHRS) collimator. The C-SPECT system with the MEHRS collimator assessed image quality and quantification using a striated phantom. Different reconstruction methods and scattering correction settings were compared, including filtered back projection (FBP) and ordered subset expectation maximization (OSEM). Higher %contrast and %CV values were observed > 10% subwindow (SW) for all conditions, with no significant differences between images without scattering correction and those < 7% SW. The FBP images show a greater increase in %CV > 10% SW than the OSEM images. The specific binding ratio in the radioactivity ratio of 8:1 was higher than the true value under all conditions. The C-SPECT system with an MEHRS collimator provided accurate scattering suppression and enabled high-quality imaging for DAT-SPECT. Careful setting of the scattering correction is essential for total count accuracy. [ABSTRACT FROM AUTHOR]

Background: It is widely known that there is low striatal 123I‐2β‐Carbomethoxy‐3β‐(4‐iodophenyl)‐N‐(3‐ fluoropropyl) nortropane (123I‐FP‐CIT) dopamine transporter single photon emission tomography (DaT‐SPECT) uptake in patients with dementia with Lewy bodies (DLB). No studies to date have analyzed the association between longitudinal changes of clinical features and DaT uptake in patients with Parkinson syndrome, particularly those with DLB. The aim of this study was to investigate the association between the longitudinal changes in DaT uptake and the severity of parkinsonism and cognitive function in DLB patients. Methods: A total of 35 outpatients with probable DLB who underwent DaT‐SPECT twice (at the initial examination and the follow‐up period) in the Memory Disorder Clinic at the Department of Geriatric Medicine, Tokyo Medical University, were enrolled in this study between April 2014 and September 2020. The correlation between annual changes in DaT uptake and clinical features (cognitive function decline and parkinsonism) of the patients was analyzed. Results: A significant correlation was detected between annual changes in parkinsonism symptom severity and DaT uptake in the left posterior putamen (r = −0.39, P = 0.03), and between Mini‐Mental State Examination scores and DaT uptake in all regions except the right posterior putamen (P < 0.05) in patients with DLB. Conclusions: Our results suggested that the pathway from the ventrolateral tier of the substantia nigra to the putamen might be more crucial for motor function than other pathways, not only in Parkinson's disease but also in DLB. [ABSTRACT FROM AUTHOR]

Abstract Background Cerebrospinal fluid (CSF) area mask correction reduces the influence of low [123I]-N-fluoropropyl-2b-carbomethoxy-3b-(4-iodophenyl) nortropane (123I-FP-CIT) accumulation in the volume of interest (VOI) by CSF area dilatation on the specific binding ratio (SBR) calculated using the Southampton method. We assessed the effect of CSF area mask correction on the SBR for idiopathic normal pressure hydrocephalus (iNPH) characterized by CSF area dilatation. Methods We enrolled 25 patients with iNPH who were assessed using 123I-FP-CIT single-photon emission computed tomography (SPECT) before shunt surgery or the tap test. The SBRs with and without CSF area mask correction were calculated, and changes in quantitative values were verified. Additionally, the number of voxels in the striatal and background (BG) VOI before and after CSF area mask correction were extracted. The number of voxels after correction was subtracted from that before correction, and the volume removed by the CSF area mask correction was calculated. The volumes removed from each VOI were compared to verify their effect on SBR. Results The images of 20 and 5 patients with SBRs that were decreased and increased, respectively, by CSF area mask correction showed that the volumes removed from the BG region VOI were higher and lower, respectively than those in the striatal region. Conclusions The SBR before and after CSF area mask correction was associated with the ratio of the volume removed from the striatal and BG VOIs, and the SBR was high or low according to the ratio. The results suggest that CSF area mask correction is effective in patients with iNPH. Trial registration This study was registered in the UMIN Clinical Trials Registry (UMIN-CTR) as UMIN study ID: UMIN000044826. 11/07/2021.

Purpose: The benefit from attenuation and scatter correction (ASC) of dopamine transporter (DAT)-SPECT for the detection of nigrostriatal degeneration in clinical routine is still a matter of debate. The current study evaluated the impact of ASC on visual interpretation and semi-quantitative analysis of DAT-SPECT in a large patient sample. Methods: One thousand seven hundred forty consecutive DAT-SPECT with 123I-FP-CIT from clinical routine were included retrospectively. SPECT images were reconstructed iteratively without and with ASC. Attenuation correction was based on uniform attenuation maps, scatter correction on simulation. All SPECT images were categorized with respect to the presence versus the absence of Parkinson-typical reduction of striatal 123I-FP-CIT uptake by three independent readers. Image reading was performed twice to assess intra-reader variability. The specific 123I-FP-CIT binding ratio (SBR) was used for automatic categorization, separately with and without ASC. Results: The mean proportion of cases with discrepant categorization by the same reader between the two reading sessions was practically the same without and with ASC, about 2.2%. The proportion of DAT-SPECT with discrepant categorization without versus with ASC by the same reader was 1.66% ± 0.50% (1.09–1.95%), not exceeding the benchmark of 2.2% from intra-reader variability. This also applied to automatic categorization of the DAT-SPECT images based on the putamen SBR (1.78% discrepant cases between without versus with ASC). Conclusion: Given the large sample size, the current findings provide strong evidence against a relevant impact of ASC with uniform attenuation and simulation-based scatter correction on the clinical utility of DAT-SPECT to detect nigrostriatal degeneration in patients with clinically uncertain parkinsonian syndrome. [ABSTRACT FROM AUTHOR]

Background: Parkinson's disease is a progressive neurodegenerative disorder, with incidence and prevalence rates of 8–18 per 100,000 people per year and 0.3–1%, respectively. As parkinsonian symptoms do not appear until approximately 50–60% of the nigral DA-releasing neurons have been lost, the impact of routine structural imaging findings is minimal at early stages, making Parkinson's disease an ideal condition for the application of functional imaging techniques. The aim of this multicenter study is to assess whether 123I-FP-CIT (DAT-SPECT), 123I-MIBG (mIBG-scintigraphy) or an association of both exams presents the highest diagnostic accuracy in de novo PD patients. Methods: 288 consecutive patients with suspected diagnoses of Parkinson's disease or non- Parkinson's disease syndromes were analyzed in the present Italian multicenter retrospective study. All subjects were de novo, drug-naive patients and met the inclusion criteria of having undergone both DAT-SPECT and mIBG-scintigraphy within one month of each other. Results: The univariate analysis including age and both mIBG-SPECT and DAT-SPECT parameters showed that the only significant values for predicting Parkinson's disease in our population were eH/M, lH/M, ESS and LSS obtained from mIBG-scintigraphy (p < 0.001). Conclusions: mIBG-scintigraphy shows higher diagnostic accuracy in de novo Parkinson's disease patients than DAT-SPECT, so given the superiority of the MIBG study, the combined use of both exams does not appear to be mandatory in the early phase of Parkinson's disease. [ABSTRACT FROM AUTHOR]

Background: Cerebrospinal fluid (CSF) area mask correction reduces the influence of low [123I]-N-fluoropropyl-2b-carbomethoxy-3b-(4-iodophenyl) nortropane (123I-FP-CIT) accumulation in the volume of interest (VOI) by CSF area dilatation on the specific binding ratio (SBR) calculated using the Southampton method. We assessed the effect of CSF area mask correction on the SBR for idiopathic normal pressure hydrocephalus (iNPH) characterized by CSF area dilatation. Methods: We enrolled 25 patients with iNPH who were assessed using 123I-FP-CIT single-photon emission computed tomography (SPECT) before shunt surgery or the tap test. The SBRs with and without CSF area mask correction were calculated, and changes in quantitative values were verified. Additionally, the number of voxels in the striatal and background (BG) VOI before and after CSF area mask correction were extracted. The number of voxels after correction was subtracted from that before correction, and the volume removed by the CSF area mask correction was calculated. The volumes removed from each VOI were compared to verify their effect on SBR. Results: The images of 20 and 5 patients with SBRs that were decreased and increased, respectively, by CSF area mask correction showed that the volumes removed from the BG region VOI were higher and lower, respectively than those in the striatal region. Conclusions: The SBR before and after CSF area mask correction was associated with the ratio of the volume removed from the striatal and BG VOIs, and the SBR was high or low according to the ratio. The results suggest that CSF area mask correction is effective in patients with iNPH. Trial registration: This study was registered in the UMIN Clinical Trials Registry (UMIN-CTR) as UMIN study ID: UMIN000044826. 11/07/2021. [ABSTRACT FROM AUTHOR]

Purpose: In Lewy body diseases (LBD), various symptoms occur depending on the distribution of Lewy body in the brain, and the findings of brain perfusion and dopamine transporter single-photon emission computed tomography (DAT-SPECT) also change accordingly. We aimed to evaluate the correlation between brain perfusion SPECT and quantitative indices calculated from DAT-SPECT in patients with LBD. Procedures: We retrospectively enrolled 35 patients with LBD who underwent brain perfusion SPECT with N-isopropyl-p-[123I] iodoamphetamine and DAT-SPECT with 123I-ioflupane. Mini-mental state examination (MMSE) data were also collected from 19 patients. Quantitative indices (specific binding ratio [SBR], putamen-to-caudate ratio [PCR], and caudate-to-putamen ratio [CPR]) were calculated using DAT-SPECT. These data were analysed by the statistical parametric mapping procedure. Results: In patients with LBD, decreased PCR index correlated with hypoperfusion in the brainstem (medulla oblongata and midbrain) (uncorrected p < 0.001, k > 100), while decreased CPR index correlated with hypoperfusion in the right temporoparietal cortex (family-wise error corrected p < 0.05), right precuneus (uncorrected p < 0.001, k > 100), and bilateral temporal cortex (uncorrected p < 0.001, k > 100). However, there was no significant correlation between decreased SBR index and brain perfusion. Additionally, the MMSE score was correlated with hypoperfusion in the left temporoparietal cortex (uncorrected p < 0.001). Conclusions: This study suggests that regional changes in striatal 123I-ioflupane accumulation on DAT-SPECT are related to brain perfusion changes in patients with LBD. [ABSTRACT FROM AUTHOR]

Background: Parkinson’s disease is a progressive neurodegenerative disorder, with incidence and prevalence rates of 8–18 per 100,000 people per year and 0.3–1%, respectively. As parkinsonian symptoms do not appear until approximately 50–60% of the nigral DA-releasing neurons have been lost, the impact of routine structural imaging findings is minimal at early stages, making Parkinson’s disease an ideal condition for the application of functional imaging techniques. The aim of this multicenter study is to assess whether 123I-FP-CIT (DAT-SPECT), 123I-MIBG (mIBG-scintigraphy) or an association of both exams presents the highest diagnostic accuracy in de novo PD patients. Methods: 288 consecutive patients with suspected diagnoses of Parkinson’s disease or non- Parkinson’s disease syndromes were analyzed in the present Italian multicenter retrospective study. All subjects were de novo, drug-naive patients and met the inclusion criteria of having undergone both DAT-SPECT and mIBG-scintigraphy within one month of each other. Results: The univariate analysis including age and both mIBG-SPECT and DAT-SPECT parameters showed that the only significant values for predicting Parkinson’s disease in our population were eH/M, lH/M, ESS and LSS obtained from mIBG-scintigraphy (p < 0.001). Conclusions: mIBG-scintigraphy shows higher diagnostic accuracy in de novo Parkinson’s disease patients than DAT-SPECT, so given the superiority of the MIBG study, the combined use of both exams does not appear to be mandatory in the early phase of Parkinson’s disease.

Abstract Background A cerebrospinal fluid (CSF)-mask algorithm has been developed to reduce the adverse influence of CSF-low-counts on the diagnostic utility of the specific binding ratio (SBR) index calculated with Southampton method. We assessed the effect of the CSF-mask algorithm on the diagnostic performance of the SBR index for parkinsonian syndromes (PS), including Parkinson’s disease, and the influence of cerebral ventricle dilatation on the CSF-mask algorithm. Methods We enrolled 163 and 158 patients with and without PS, respectively. Both the conventional SBR (non-CSF-mask) and SBR corrected with the CSF-mask algorithm (CSF-mask) were calculated from 123I-Ioflupane single-photon emission computed tomography (SPECT) images of these patients. We compared the diagnostic performance of the corresponding indices and evaluated whether the effect of the CSF-mask algorithm varied according to the extent of ventricle dilatation, as assessed with the Evans index (EI). A receiver-operating characteristics (ROC) analysis was used for statistical analyses. Results ROC analyses demonstrated that the CSF-mask algorithm performed better than the non-CSF-mask (no correction, area under the curve [AUC] = 0.917 [95% confidence interval (CI) 0.887–0.947] vs. 0.895 [95% CI 0.861–0.929], p

Aims: This study aimed to analyze the performance of multi-atlas MRI-based parcellation for 123I-FP-CIT SPECT (DAT-SPECT) in healthy volunteers. The proposed method was compared with the SPECT-atlas-based and Bolt methods. 18F-FE-PE2I-PET (DAT-PET) was used as a reference.Methods: Thirty healthy subjects underwent DAT-SPECT, DAT-PET, and 3D-T1WI-MRI. We calculated the striatum uptake ratio (SUR/SBR), caudate uptake ratio (CUR), and putamen uptake ratio (PUR) for DAT-SPECT using the multi-atlas MRI-based method, SPECT-atlas-based method, and Bolt method. In the multi-atlas MRI-based method, the cerebellum, occipital cortex, and whole-brain were used as reference regions. The correlation of age with DAT-SPECT activity and the correlations of SUR/SBR, CUR, and PUR between DAT-SPECT and DAT-PET were calculated by each of the three methods.Results: The correlation between age and SUR/SBR for DAT-SPECT based on the multi-atlas MRI-based method was comparable to that based on the SPECT-atlas-based method (r = −0.441 to −0.496 vs. −0.488). The highest correlation between DAT-SPECT and DAT-PET was observed using the multi-atlas MRI-based method with the occipital lobe defined as the reference region compared with the SPECT-atlas-based and Bolt methods (SUR, CUR, and PUR: 0.687, 0.723, and 0.676 vs. 0.698, 0.660, and 0.616 vs. 0.655).Conclusion: Multi-atlas MRI-based parcellation with the occipital lobe defined as the reference region was at least comparable to the clinical methods.

Purpose: We aimed to evaluate the diagnostic performances of quantitative indices obtained from dopamine transporter (DAT) single-photon emission computed tomography (SPECT) and 123I-metaiodobenzylguanidine (MIBG) scintigraphy for Parkinsonian syndromes (PS) using the classification and regression tree (CART) analysis. Methods: We retrospectively enrolled 216 patients with or without PS, including 80 without PS (NPS) and 136 with PS [90 Parkinson's disease (PD), 21 dementia with Lewy bodies (DLB), 16 progressive supranuclear palsy (PSP), and 9 multiple system atrophy (MSA). The striatal binding ratio (SBR), putamen-to-caudate ratio (PCR), and asymmetry index (AI) were calculated using DAT SPECT. The heart-to-mediastinum uptake ratio (H/M) based on the early (H/M [Early]) and delayed (H/M [Delay]) images and cardiac washout rate (WR) were calculated from MIBG scintigraphy. The CART analysis was used to establish a diagnostic decision tree model for differentiating PS based on these quantitative indices. Results: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 87.5, 96.3, 93.3, 92.9, and 93.1 for NPS; 91.1, 78.6, 75.2, 92.5, and 83.8 for PD; 57.1, 95.9, 60.0, 95.4, and 92.1 for DLB; and 50.0, 98.0, 66.7, 96.1, and 94.4 for PSP, respectively. The PCR, WR, H/M (Delay), and SBR indices played important roles in the optimal decision tree model, and their feature importance was 0.61, 0.22, 0.11, and 0.05, respectively. Conclusion: The quantitative indices showed high diagnostic performances in differentiating NPS, PD, DLB, and PSP, but not MSA. Our findings provide useful guidance on how to apply these quantitative indices in clinical practice. [ABSTRACT FROM AUTHOR]

Dementia with Lewy bodies (DLB) is the second most common form of dementia and is assumed to be often under- or misdiagnosed, especially in early stages. Here we present a complex case of probable DLB with major depression and alcohol and benzodiazepine dependence in which DLB was ruled out initially. This case highlights the challenging diagnostic workup of DLB patients. Core clinical features can be missing and indicative biomarkers can be negative, especially in early stages of the disease. Initially, Fluorodeoxyglucose positron emission tomography as well as neuropsychological assessment were suspicious for a possible DLB diagnosis in our patient while core clinical criteria were missing and the indicative biomarker 123I-FP-CIT SPECT was negative. Follow up was performed two years later and the patients showed several core and supportive clinical features of DLB and 123I-FP-CIT SPECT showed a pathological pattern. Extensive neuropsychological assessment in combination with PET imaging might provide crucial evidence for DLB even in early stages. If neuropsychology and PET imaging point to an early DLB diagnosis careful follow-up should be performed as core symptoms and indicative biomarkers might appear in later stages of the disease.

Abstract Background We sought to assess the machine learning-based combined diagnostic accuracy of three types of quantitative indices obtained using dopamine transporter single-photon emission computed tomography (DAT SPECT)—specific binding ratio (SBR), putamen-to-caudate ratio (PCR)/fractal dimension (FD), and asymmetry index (AI)—for parkinsonian syndrome (PS). We also aimed to compare the effect of two different types of volume of interest (VOI) settings from commercially available software packages DaTQUANT (Q) and DaTView (V) on diagnostic accuracy. Methods Seventy-one patients with PS and 40 without PS (NPS) were enrolled. Using SPECT images obtained from these patients, three quantitative indices were calculated at two different VOI settings each. SBR-Q, PCR-Q, and AI-Q were derived using the VOI settings from DaTQUANT, whereas SBR-V, FD-V, and AI-V were derived using those from DaTView. We compared the diagnostic value of these six indices for PS. We incorporated a support vector machine (SVM) classifier for assessing the combined accuracy of the three indices (SVM-Q: combination of SBR-Q, PCR-Q, and AI-Q; SVM-V: combination of SBR-V, FD-V, and AI-V). A Mann-Whitney U test and receiver-operating characteristics (ROC) analysis were used for statistical analyses. Results ROC analyses demonstrated that the areas under the curve (AUC) for SBR-Q, PCR-Q, AI-Q, SBR-V, FD-V, and AI-V were 0.978, 0.837, 0.802, 0.906, 0.972, and 0.829, respectively. On comparing the corresponding quantitative indices between the two types of VOI settings, SBR-Q performed better than SBR-V (p = 0.006), whereas FD-V performed better than PCR-Q (p = 0.0003). No significant difference was observed between AI-Q and AI-V (p = 0.56). The AUCs for SVM-Q and SVM-V were 0.988 and 0.994, respectively; the two different VOI settings displayed no significant differences in terms of diagnostic accuracy (p = 0.48). Conclusion The combination of the three indices obtained using the SVM classifier improved the diagnostic performance for PS; this performance did not differ based on the VOI settings and software used.

Objective: Aging decreases dopamine transporter (DAT) availability of striatum both in humans and rodents. We aimed to investigate the relationship of DAT availabilities from ventral striatum, caudate nucleus, and putamen with aging in healthy subjects. Methods: 123I-FP-CIT single photon emission computed tomography (SPECT) was performed in all subjects. Specific binding of 123I-FP-CIT regarding DAT was calculated using a volume-of-interest-based analysis of ventral striatum, caudate nucleus, putamen. The cerebellum was chosen as a reference region. Specific binding ratios (SBRs) were calculated as follows: SBR = (target– cerebellum)/cerebellum. Results: A total of 166 healthy subjects (109 males and 57 females) were included in this study. SBRs of ventral striatum, caudate nucleus, and putamen were negatively correlated with age. In young males, SBRs of ventral striatum and putamen were not correlated with aging. However, SBRs of caudate nucleus showed the trend toward negative correlation with age in the young group. In old males, SBR of caudate nucleus was negatively correlated with age and SBR of ventral striatum showed a trend toward negative correlation with age. Slopes of regression lines were not significantly different according to age groups in ventral striatum, caudate nucleus, or putamen. SBRs of ventral striatum, caudate nucleus, and putamen were negatively correlated with age in young females, but not in old females. Interestingly, slopes of regression line were significantly different between young and old females in ventral striatum, caudate nucleus, and putamen. Conclusions: We have shown that slopes of regression lines of DAT availabilities and age were significantly different between young and old subjects in females, not in males. Therefore, sex has an impact on aging-related decline of striatal DAT availability. [ABSTRACT FROM AUTHOR]

Rationale: Dopamine transporter (DAT) imaging is an important adjunct in the diagnostic workup of patients with Parkinsonism. 18F-FE-PE2I is a suitable PET radioligand for DAT quantification and imaging with good pharmacokinetics. The aim of this study was to determine a clinical optimal simplified reference tissue-based image acquisition protocol and to compare the discriminatory value and effect size for 18F-FE-PE2I to that for 123I-FP-CIT scan currently used in clinical practice. Methods: Nine patients with early Parkinson's disease (PD, 64.3 ± 6.8 years, 3M), who had previously undergone a 123I-FP-CIT scan as part of their diagnostic workup, and 34 healthy volunteers (HV, 47.7 ± 16.8 years, 13M) underwent a 60-min dynamic 18F-FE-PE2I PET-MR scan on a GE Signa 3T PET-MR. Based on dynamic data and MR-based VOI delineation, BPND, semi-quantitative uptake ratio and SUVR[t1–t2] images were calculated using either occipital cortex or cerebellum as reference region. For start-and-end time of the SUVR interval, three time frames [t1–t2] were investigated: [15–40] min, [40–60] min, and [50–60] min postinjection. Data for putamen (PUT) and caudate nucleus-putamen ratio (CPR) were compared in terms of quantification bias versus BPND and discriminative power. Results: Using occipital cortex as reference region resulted in smaller bias of SUVR with respect to BPND + 1 and higher correlation between SUVR and BPND + 1 compared with using cerebellum, irrespective of SUVR [t1–t2] interval. Smallest bias was observed with the [15–40]-min time window, in accordance with previous literature. The correlation between BPND + 1 and SUVR was slightly better for the late time windows. Discriminant analysis between PD and HV using both PUT and CPR SUVRs showed an accuracy of ≥ 90%, for both reference regions and all studied time windows. Semi-quantitative 123I-FP-CIT and 18F-FE-PE2I values and relative decrease in the striatum for patients were highly correlated, with a higher effect size for 18F-FE-PE2I for PUT and CPR SUVR. Conclusion: 18F-FE-PE2I is a suitable radioligand for in vivo DAT imaging with high discriminative power between early PD and healthy controls. Whereas a [15–40]-min window has lowest bias with respect to BPND, a [50–60]-min time window at pseudoequilibrium can be advocated in terms of clinical feasibility with optimal discriminative power. The occipital cortex may be slightly preferable as reference region because of the higher time stability, stronger correlation of SUVR with BPND + 1, and lower bias. Moreover, the data suggest that the diagnostic accuracy of a 10-min static 18F-FE-PE2I scan is non-inferior compared with 123I-FP-CIT scan used in standard clinical practice. [ABSTRACT FROM AUTHOR]

Dementia with Lewy bodies (DLB) is the second most common form of dementia and is assumed to be often under- or misdiagnosed, especially in early stages. Here we present a complex case of probable DLB with major depression and alcohol and benzodiazepine dependence in which DLB was ruled out initially. This case highlights the challenging diagnostic workup of DLB patients. Core clinical features can be missing and indicative biomarkers can be negative, especially in early stages of the disease. Initially, Fluorodeoxyglucose positron emission tomography as well as neuropsychological assessment were suspicious for a possible DLB diagnosis in our patient while core clinical criteria were missing and the indicative biomarker 123I-FP-CIT SPECT was negative. Follow up was performed two years later and the patients showed several core and supportive clinical features of DLB and 123I-FP-CIT SPECT showed a pathological pattern. Extensive neuropsychological assessment in combination with PET imaging might provide crucial evidence for DLB even in early stages. If neuropsychology and PET imaging point to an early DLB diagnosis careful follow-up should be performed as core symptoms and indicative biomarkers might appear in later stages of the disease. [ABSTRACT FROM AUTHOR]

• Anatomically accurate delineation of volumes-of-interest. • Full recovery of striatal uptake. • Implemented solely via free and open-source software. Functional imaging with 123I-FP-CIT SPECT suffers from poor spatial resolution resulting in partial-volume effect, which affects the subsequent semi-quantification. Definition of regions of interest for semi-quantification is further subject to user's experience and inter-observer variability. The aim of this work has been to develop an automatic method for definition of volumes of interest and partial-volume correction using patient-specific MRI and providing complete contrast recovery in striatal region. The method consists of spatial pre-processing (image segmentation and multi-modality registration), partial-volume correction (performed by region-based voxel-wise technique), and calculation of uptake indices in striatal structures. Anthropomorphic striatal phantom was used to optimize the method and to assess linearity, accuracy, and reproducibility. The method was tested on 58 patient datasets and compared with clinical assessment and BasGan software. The method works automatically. The output is highly linear regarding changing striatal uptake. Complete contrast recovery is achieved using 6.5 mm FWHM. Accuracy is better than 0.15 in terms of RMSE between measured and true uptake indices. Reproducibility is better than 5% for normal uptake ratio. The method outperformed clinical assessment in all measures. With patient data, it provided results closer to BasGan (RMSE 0.9) than to clinical assessment (RMSE 1.9) and fairly correlated with both. The proposed method provides complete recovery of striatal contrast under given acquisition and reconstruction conditions. It reduces intra- and inter-observer variability, accurately defines volumes of interest, and effectively suppresses partial-volume effect. It can be reproduced using publicly available software. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of the acquisition rotation speed and the rotation time for continuous repetitive rotation acquisition (CRRA) on image quality and quantification in 123I-FP-CIT SPECT. Methods: An anthropomorphic striatal phantom filled with 123I solution was acquired with CRRA and the step-and-shoot (SS) mode. The following combinations of acquisition rotation speed and rotation time for CRRA were used: 0.50 rpm by 30 frames, 0.17 rpm by 10 frames, 0.10 rpm by 6 frames, and 0.05 rpm by 3 frames. SPECT images were reconstructed using ordered-subset expectation maximization with resolution recovery, scatter, and CT-based attenuation correction. Two kinds of image processing patterns-image reconstruction after the addition of projection data (the added-projection-data process) and image addition after data reconstruction (the added-reconstructed-image process)-were investigated in this study. The effects of the acquisition parameters and the image processes were evaluated by the full width at half maximum, percentage coefficient of variation (%CV), and specific binding ratio (SBR). Results: With full width at half maximum, there were no clear differences between CRRA images obtained with the various rotation speeds before rotation and the SS mode. Although the combination of a slow rotation speed and a short rotation time improved image uniformity compared with the SS mode, the %CV obtained by CRRA increased as the rotation speed increased. The %CVs were 11.9% ± 0.9% for 0.50 rpm by 30 frames, 6.9% ± 0.9% for 0.05 rpm by 3 frames, and 9.6% ± 0.5% for SS mode. SBRs obtained by CRRA with the added-projection-data process were equal to those obtained by SS mode. However, SBRs obtained with the added-reconstructed-image process were clearly decreased compared with the SS mode. Conclusion: The combination of rotation speed and rotation times affects the image quality and quantification of 123I-FP-CIT SPECT using CRRA. When CRRA is applied in 123I-FP-CIT SPECT, it is necessary to use added-projection-data processes and proper rotation speeds (e.g., 0.10-0.17 rpm rotation speed). [ABSTRACT FROM AUTHOR]

Background: Neuromelanin magnetic resonance imaging (NmMRI) and 123I-FP-CIT dopamine transporter single photon emission computed tomography (DAT-SPECT) provide specific information that distinguishes Parkinson's disease (PD) from non-degenerative parkinsonian syndrome (NDPS).Purpose: To determine whether a multiparametric scoring system (MSS) could improve accuracy compared to each parameter of DAT-SPECT and NmMRI in differentiating PD from NDPS.Material and Methods: A total of 49 patients, including 14 with NDPS, 30 with PD, and five with atypical parkinsonian disorder (APD) underwent both NmMRI and DAT-SPECT and were evaluated. The average (Ave) and the asymmetry index (AI) were calculated in the substantia nigra compacta area (SNc-area), SNc midbrain-tegmentum contrast ratio (SNc-CR), and specific binding ratio (SBR). Cut-off values were determined, using receiver operating characteristic (ROC) analysis, for the differentiation of PD from NDPS on the statistically significant parameters. All cases were scored as either 1 (PD) or 0 (NDPS) for each parameter according to its threshold. These individual scores were totaled for each case, yielding a combined score for each case to obtain a cut-off value for the MSS.Results: The Ave-SNc-area, Ave-SNc-CR, and Ave-SBR in PD were significantly lower than those in NDPS. The AI-SNc-area and AI-SBR in PD were significantly higher than those in NDPS. Of the five parameters, the highest accuracy was 93% for the Ave-SNc-area. For the MSS, a cut-off value of 3 was the accuracy of 96%. Besides, no significant difference was observed between PD and APD on all parameters.Conclusion: An MSS has comparable or better accuracy compared to each parameter of DAT-SPECT and NmMRI in distinguishing PD from NDPS. [ABSTRACT FROM AUTHOR]

Abstract: 123I‐FP‐CIT and 18F‐FP‐CIT are radiotracers which are widely used to diagnose Parkinson's disease (PD). However, to our knowledge, no studies to date have made head‐to‐head comparisons between 123I‐FP‐CIT and 18F‐FP‐CIT. Therefore, in this study, 123I‐FP‐CIT SPECT/CT was compared with 18F‐FP‐CIT PET/CT in the same cohort of subjects. Patients with PD and essential tremor (ET) underwent 123I‐FP‐CIT SPECT/CT and 18F‐FP‐CIT PET/CT. Visual and semiquantitative analyses were conducted. The specific binding ratio (SBR) and putamen to caudate ratio (PCR) were compared between subjects who underwent 123I‐FP‐CIT SPECT/CT and 18F‐FP‐CIT PET/CT. Visual analysis showed that the striatal uptake of both radiotracers was decreased in the PD group, whereas striatal uptake was intact in the ET group. The SBR between 123I‐FP‐CIT SPECT/CT and 18F‐FP‐CIT PET/CT showed a positive correlation (r = .78, p < .01). However, the mean SBRs on 18F‐FP‐CIT PET/CT were higher than those on 123I‐FP‐CIT SPECT/CT (2.19 ± .87 and 1.22 ± .49, respectively; p < .01). The PCRs in these two modalities were correlated with each other (r = .71, p < .01). The mean PCRs on 18F‐FP‐CIT PET/CT were not significantly higher than those on 123I‐FP‐CIT SPECT/CT (1.31 ± .19 and 0.98 ± .06, respectively; p = .06). These preliminary results indicate that the uptake of both 123I‐FP‐CIT and 18F‐FP‐CIT was decreased in the PD group when compared with the ET controls. Visual analyses using both methods did not affect the diagnostic accuracy in this study. However, semiquantitative analysis indicated a better contrast of 18F‐FP‐CIT PET/CT relative to 123I‐FP‐CIT SPECT/CT. [ABSTRACT FROM AUTHOR]

Background 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy and 123I-FP-CIT dopamine transporter single photon emission computed tomography (DAT-SPECT) provide specific information that distinguish Parkinson's disease (PD) from parkinsonian syndromes other than PD (non-PD), including atypical parkinsonian disorder (APD) and non-PD other than APD (nPD-nAPD). The purpose of this study was to determine whether combining DAT-SPECT and MIBG myocardial scintigraphy using multiparametric scoring system (MSS) could improve diagnostic test accuracy in discriminating PD from APD or discriminating PD from nPD-nAPD. Methods A total of 52 patients, including 36 PD, eight APD and eight nPD-nAPD, underwent both MIBG myocardial scintigraphy and DAT-SPECT, were evaluated. The heart-to-mediastinum (H/M) ratios (early and delayed), washout-rate (WR), the average (Ave) and asymmetry index (AI) of specific binding ratio (SBR) were calculated. Cutoff values were determined, using ROC analysis, for discriminating PD from APD and for discriminating PD from nPD-nAPD, on five parameters. All cases were scored as either 1 (PD) or 0 (nPD-nAPD or APD) for each parameter according to its threshold in each discrimination. These individual scores were summed for each case, yielding a combined score to obtain a cutoff value for the MSS in each discrimination. Results For discriminating PD from nPD-nAPD, thehighest accuracy was 80% at a cutoff value of 19% for the WR and a cut off value of 2 improved diagnostic accuracy to 84% for MSS. For discriminating PD from APD, the highest accuracy was 86% at a cutoff value of 2.8 for the H/M ratio (late) and a cut off value of 2 showed diagnostic accuracy of 86% for MSS. Conclusion A MSS has comparable or better accuracy compared to each parameter of MIBG myocardial scintigraphy and DAT-SPECT in distinguishing PD from nPD-nAPD or distinguishing PD from APD. [ABSTRACT FROM AUTHOR]

Purpose: Quantification of the tracer distribution would add objectivity to the visual assessments of dopamine transporter (DAT) single photon emission computed tomography (SPECT) data. Our study aimed to evaluate the diagnostic utility of fractal dimension (FD) as a quantitative indicator of tracer distribution and compared with the conventional quantitative value: specific binding ratio (SBR). We also evaluated the utility of the combined index SBR/FD (SBR divided by FD).Materials and Methods: We conducted both clinical and phantom studies. In the clinical study, 150 patients including 110 patients with Parkinsonian syndrome (PS) and 40 without PS were enrolled. In the phantom study, we used a striatal phantom with the striatum chamber divided into two spaces, representing the caudate nucleus and putamen. The SBR, FD, and SBR/FD were calculated and compared between datasets for evaluating the diagnostic utility. Mann-Whitney test and receiver-operating characteristics (ROC) analysis were used for analysis.Results: ROC analysis revealed that the FD value had high diagnostic performance [the areas under the curve (AUC) = 0.943] and the combined use of SBR and FD (SBR/FD) delivered better results than the SBR alone (AUC, 0.964 vs 0.899; p < 0.001). The sensitivity, specificity, and accuracy, respectively, were 79.1, 85.0, and 80.7% with SBR, 84.5, 97.5, and 88.0% with FD, and 92.7, 87.5, and 91.3% with SBR/FD.Conclusion: Our results confirmed that the FD value is a useful diagnostic index, which reflects the tracer distribution in DAT SPECT images. The combined use of SBR and FD was more useful than either used alone. [ABSTRACT FROM AUTHOR]

Objective: In Japan, the Southampton method for dopamine transporter (DAT) SPECT is widely used to quantitatively evaluate striatal radioactivity. The specific binding ratio (SBR) is the ratio of specific to non-specific binding observed after placing pentagonal striatal voxels of interest (VOIs) as references. Although the method can reduce the partial volume effect, the SBR may fluctuate due to the presence of low-count areas of cerebrospinal fluid (CSF), caused by brain atrophy, in the striatal VOIs. We examined the effect of the exclusion of low-count VOIs on SBR measurement.Methods: We retrospectively reviewed DAT imaging of 36 patients with parkinsonian syndromes performed after injection of 123I-FP-CIT. SPECT data were reconstructed using three conditions. We defined the CSF area in each SPECT image after segmenting the brain tissues. A merged image of gray and white matter images was constructed from each patient's magnetic resonance imaging (MRI) to create an idealized brain image that excluded the CSF fraction (MRI-mask method). We calculated the SBR and asymmetric index (AI) in the MRI-mask method for each reconstruction condition. We then calculated the mean and standard deviation (SD) of voxel RI counts in the reference VOI without the striatal VOIs in each image, and determined the SBR by excluding the low-count pixels (threshold method) using five thresholds: mean-0.0SD, mean-0.5SD, mean-1.0SD, mean-1.5SD, and mean-2.0SD. We also calculated the AIs from the SBRs measured using the threshold method. We examined the correlation among the SBRs of the threshold method, between the uncorrected SBRs and the SBRs of the MRI-mask method, and between the uncorrected AIs and the AIs of the MRI-mask method.Results: The intraclass correlation coefficient indicated an extremely high correlation among the SBRs and among the AIs of the MRI-mask and threshold methods at thresholds between mean-2.0D and mean-1.0SD, regardless of the reconstruction correction. The differences among the SBRs and the AIs of the two methods were smallest at thresholds between man-2.0SD and mean-1.0SD.Conclusion: The SBR calculated using the threshold method was highly correlated with the MRI-SBR. These results suggest that the CSF correction of the threshold method is effective for the calculation of idealized SBR and AI values. [ABSTRACT FROM AUTHOR]

The study aim was to evaluate the adaptation of collimators to 123 I- N -fluoropropyl-2b-carbomethoxy-3b-(4-iodophenyl)nortropane ( 123 I-FP-CIT) dopamine transporter SPECT (DAT-SPECT) by a high-resolution whole-body SPECT/CT system with a cadmium-zinc-telluride detector (C-SPECT) in terms of image quality, quantitation, diagnostic performance, and acquisition time. Methods: Using a C-SPECT device equipped with a wide-energy, high-resolution collimator and a medium-energy, high-resolution sensitivity (MEHRS) collimator, we evaluated the image quality and quantification of DAT-SPECT for an anthropomorphic striatal phantom. Ordered-subset expectation maximization iterative reconstruction with resolution recovery, scatter, and attenuation correction was used, and the optimal collimator was determined on the basis of the contrast-to-noise ratio (CNR), percentage contrast, and specific binding ratio. The acquisition time that could be reduced using the optimal collimator was determined. The optimal collimator was used to retrospectively evaluate diagnostic accuracy via receiver-operating-characteristic analysis and specific binding ratios for 41 consecutive patients who underwent DAT-SPECT. Results: When the collimators were compared in the phantom verification, the CNR and percentage contrast were significantly higher for the MEHRS collimator than for the wide-energy high-resolution collimator ( P < 0.05). There was no significant difference in the CNR between 30 and 15 min of imaging time using the MEHRS collimator. In the clinical study, the areas under the curve for acquisition times of 30 and 15 min were 0.927 and 0.906, respectively, and the diagnostic accuracies of the DAT-SPECT images did not significantly differ between the 2 times. Conclusion: The MEHRS collimator provided the best results for DAT-SPECT with C-SPECT; shorter acquisition times (<15 min) may be possible with injected activity of 167-186 MBq., (© 2023 by the Society of Nuclear Medicine and Molecular Imaging.)

Background N-ω-fluoropropyl-2b-carbomethoxy-3b-(4-123I-iodophenyl) nortropane (123I- FP- CIT) single-photon emission computed tomography is an effective diagnostic tool for parkinsonism . However, a lack of quantitative reference values of the specific binding ratio of normal Japanese controls is a crucial limitation when we apply this procedure for evaluating Japanese parkinsonian patients. Aim In the present study, we aimed to obtain a control database of specific binding ratio in healthy, Japanese older adults. Methods We studied 123I- FP- CIT single-photon emission computed tomography in 20 healthy Japanese older adults, and obtained the specific binding ratio with and without attenuation correction. Results Clinically and practically relevant data were obtained from 19 participants (10 women, 9 men, age 68.7 ± 8.8 years). The mean specific binding ratio with attenuation correction ± standard deviation was 6.84 ± 1.01, being significantly higher than that of the preceding study of Caucasians by Tossici-Bolt et al. The mean specific binding ratio without attenuation correction was 5.31 ± 1.04. These were not different between the sexes. The specific binding ratio decreased age-dependently in the specific binding ratio both with and without attenuation correction. The mean decreasing rate of specific binding ratio with AC was approximately 0.7 per decade. Most of the striatal asymmetry index of specific binding ratio with AC was lower than 8.4%. Conclusion We presented the quantitative reference values of Japanese healthy older adults feasible for diagnostic and research use for Japanese parkinsonian patients. [ABSTRACT FROM AUTHOR]