Computed-tomography-guided anatomic standardization for quantitative assessment of dopamine transporter SPECT

Diagnostic Sensitivity and Symptomatic Relevance of Dopamine Transporter Imaging and Myocardial Sympathetic Scintigraphy in Patients with Dementia with Lewy Bodies

Background

Dementia with Lewy bodies (DLB) presents with various symptoms, posing challenges for early diagnosis challenging. Dopamine transporter (123I-FP-CIT) single-photon emission tomography (SPECT) and 123I-meta-iodobenzylguanidine (123I-MIBG) imaging are crucial diagnostic biomarkers. Hypothesis about body- and brain-first subtypes of DLB indicate that some DLB may show normal 123I-FP-CIT or 123I-MIBG results; but the characteristic expression of these two subtypes remains unclear.

Objective

This study aimed to evaluate the diagnostic sensitivity of 123I-FP-CIT and 123I-MIBG imaging alone, combined in patients with DLB and explore symptoms associated with the abnormal imaging results.

Methods

Demographic data, clinical status, and imaging results were retrospectively collected from patients diagnosed with possible DLB. Both images were quantified using semi-automated software, and the sensitivity of each imaging modality and their combination was calculated. Demographic data, cognition, and motor and non-motor symptoms were compared among the subgroups based on the imaging results. Symptoms related to each imaging abnormality were examined using binomial logistic regression analyses.

Results

Among 114 patients with DLB, 80 underwent 123I-FP-CIT SPECT (sensitivity: 80.3%), 83 underwent 123I-MIBG imaging (68.2%), and 66 both (sensitivity of either abnormal result: 93.9%). Visual hallucinations differed among the four subgroups based on imaging results. Additionally, nocturia and orthostatic hypotension differed between abnormal and normal 123I-MIBG images.

Conclusions

Overall, 123I-FP-CIT SPECT was slightly higher sensitivity than 123I-MIBG imaging, with combined imaging increasing diagnostic sensitivity. Normal results of a single imaging test may not refute DLB. Autonomic symptoms may lead to abnormal 123I-MIBG scintigraphy findings indicating body-first subtype of patients with DLB.

Quantitative [123]I-Ioflupane DaTSCAN single-photon computed tomography-computed tomography in Parkinsonism

AIM

[123]I-Ioflupane (DaTSCAN) binds to the presynaptic dopamine transporter (DAT) and with a lower affinity to the serotonin transporter (SERT). We aimed to develop a novel method to quantify absolute uptake in the striatal (predominantly DAT binding) and extra-striatal regions (mainly SERT binding) using single-photon computed tomography-computed tomography (SPECT-CT) DaTSCAN and to improve DaTSCAN image quality.

METHOD

Twenty-six patients with Parkinsonism underwent DaTSCAN SPECT-CT prospectively. The scans were visually analyzed independently by two experienced reporters. Specific binding ratios (SBRs) from Chang attenuation corrected SPECT were obtained using GE DaTQuant. Normalized concentrations and specific uptakes (NSU) from measured attenuation and modelled scatter-corrected SPECT-CT were obtained using HERMES Hybrid Recon and Affinity and modified EARL volumes of interest.

RESULTS

Striatal NSU and SBR positively correlate ( R  = 0.65-0.88, P  = 0.00). SBR, normalized concentrations, and NSU box plots differentiated between scans without evidence of dopaminergic deficit and abnormal scans. Interestingly, body weight inversely correlated with normalized concentrations values in extra-striatal regions [frontal ( R  = 0.81, P  = 0.00); thalamus ( R  = 0.58, P  = 0.00); occipital ( R  = 0.69, P  = 0.00)] and both caudate nuclei [ R  = 0.42, P  = 0.03 (Right), R  = 0.52, P  = 0.01 (Left)]. Both reporters noted improved visual quality of SPECT-CT versus SPECT images for all scans.

CONCLUSION

DaTSCAN SPECT-CT resulted in more accurate quantification, improved image quality, and enabled absolute quantification of extra-striatal regions. More extensive studies are required to establish the full value of absolute quantification for diagnosis and monitoring the progression of neurodegenerative disease, to assess an interplay between DAT and SERT, and to verify whether serotonin and DATs are potentially dysfunctional in obesity.

The diagnostic performance of functional dopaminergic scintigraphic imaging in the diagnosis of dementia with Lewy bodies: an updated systematic review

INTRODUCTION

Dopaminergic scintigraphic imaging is a cornerstone to support the diagnosis in dementia with Lewy bodies. To clarify the current state of knowledge on this imaging modality and its impact on clinical diagnosis, we performed an updated systematic review of the literature.

METHODS

This systematic review was carried out according to PRISMA guidelines. A comprehensive computer literature search of PubMed/MEDLINE, EMBASE, and Cochrane Library databases for studies published through June 2022 was performed using the following search algorithm: (a) "Lewy body" [TI] OR "Lewy bodies" [TI] and (b) ("DaTscan" OR "ioflupane" OR "123ip" OR "123?ip" OR "123 ip" OR "123i-FP-CIT" OR "FPCIT" OR "FP-CIT" OR "beta?CIT" OR "beta CIT" OR "CIT?SPECT" OR "CIT SPECT" OR "Dat?scan*" OR "dat scan*" OR "dat?spect*" OR "SPECT"). Risk of bias and applicability concerns of the studies were evaluated using the QUADAS-2 tool.

RESULTS

We performed a qualitative analysis of 59 studies. Of the 59 studies, 19 (32%) addressed the diagnostic performance of dopamine transporter imaging, 15 (25%) assessed the identification of dementia with Lewy bodies in the spectrum of Lewy body disease and 18 (31%) investigated the role of functional dopaminergic imaging in distinguishing dementia with Lewy bodies from other dementias. Dopamine transporter loss was correlated with clinical outcomes in 19 studies (32%) and with other functional imaging modalities in 15 studies (25%). Heterogeneous technical aspects were found among the studies through the use of various radioligands, the more prevalent being the [123I]N‑ω‑fluoropropyl‑2β‑carbomethoxy‑3β‑(4‑iodophenyl) nortropane (123I-FP-CIT) in 54 studies (91.5%). Image analysis used visual analysis (9 studies, 15%), semi-quantitative analysis (29 studies, 49%), or a combination of both (16 studies, 27%).

CONCLUSION

Our systematic review confirms the major role of dopaminergic scintigraphic imaging in the assessment of dementia with Lewy bodies. Early diagnosis could be facilitated by identifying the prodromes of dementia with Lewy bodies using dopaminergic scintigraphic imaging coupled with emphasis on clinical neuropsychiatric symptoms. Most published studies use a semi-quantitative analytical assessment of tracer uptake, while there are no studies using quantitative analytical methods to measure dopamine transporter loss. The superiority of a purely quantitative approach to assess dopaminergic transmission more accurately needs to be further clarified.

Sex correction improves the accuracy of clinical dopamine transporter imaging

Background

In clinical diagnostic imaging, dopamine transporter (DAT) SPECT scans are commonly evaluated using automated semiquantitative analysis software. Age correction is routinely implemented, but usually no sex correction of DAT binding is performed. Since there are sex differences in presynaptic dopaminergic function, we investigated the effect of DAT sex correction in a sample of healthy volunteers who underwent brain [¹²³I]-FP-CIT SPECT.

Methods

Forty healthy elderly individuals (21 men and 19 women) underwent brain [¹²³I]-FP-CIT SPECT, and each subject was examined clinically for motor and non-motor parkinsonian symptoms and signs. Regional specific DAT binding ratios (SBR = [ROI-occ]/occ) were calculated using age correction, and the results were compared to those in normal databases with and without sex correction. The level of regional abnormality was set at 2 standard deviations below the mean values of the reference databases.

Results

In the analysis without sex correction, compared to the mean ratio of the reference database, ten healthy individuals (8 men and 2 women) had abnormally low DAT binding ratios, and four individuals (3 men and 1 woman) had borderline low DAT binding ratios in at least one striatal region. When sex correction was implemented, the ratio of one individual was abnormal, and the ratio of one individual was borderline (both males). There were no clinically significant differences in motor or non-motor symptoms between healthy volunteers with abnormal and normal binding.

Conclusions

A considerable number of elderly healthy male subjects can be interpreted to be dopaminergically abnormal if no sex correction of DAT binding is performed. Sex differences in striatal dopaminergic function should be taken into account when DAT imaging is used to assist clinical diagnostics in patients with suspected neurological disorders.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13550-021-00825-3.

A diagnostic strategy for Parkinsonian syndromes using quantitative indices of DAT SPECT and MIBG scintigraphy: an investigation using the classification and regression tree analysis

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.

Creation of an anthropomorphic CT head phantom for verification of image segmentation

Purpose

Many methods are available to segment structural magnetic resonance (MR) images of the brain into different tissue types. These have generally been developed for research purposes but there is some clinical use in the diagnosis of neurodegenerative diseases such as dementia. The potential exists for computed tomography (CT) segmentation to be used in place of MRI segmentation, but this will require a method to verify the accuracy of CT processing, particularly if algorithms developed for MR are used, as MR has notably greater tissue contrast.

Methods

To investigate these issues we have created a three‐dimensional (3D) printed brain with realistic Hounsfield unit (HU) values based on tissue maps segmented directly from an individual T1 MRI scan of a normal subject. Several T1 MRI scans of normal subjects from the ADNI database were segmented using SPM12 and used to create stereolithography files of different tissues for 3D printing. The attenuation properties of several material blends were investigated, and three suitable formulations were used to print an object expected to have realistic geometry and attenuation properties. A skull was simulated by coating the object with plaster of Paris impregnated bandages. Using two CT scanners, the realism of the phantom was assessed by the measurement of HU values, SPM12 segmentation and comparison with the source data used to create the phantom.

Results

Realistic relative HU values were measured although a subtraction of 60 was required to obtain equivalence with the expected values (gray matter 32.9–35.8 phantom, 29.9–34.2 literature). Segmentation of images acquired at different kVps/mAs showed excellent agreement with the source data (Dice Similarity Coefficient 0.79 for gray matter). The performance of two scanners with two segmentation methods was compared, with the scanners found to have similar performance and with one segmentation method clearly superior to the other.

Conclusion

The ability to use 3D printing to create a realistic (in terms of geometry and attenuation properties) head phantom has been demonstrated and used in an initial assessment of CT segmentation accuracy using freely available software developed for MRI.

Two decades of SPECT/CT - the coming of age of a technology: An updated review of literature evidence

PURPOSE

Single-photon emission computed tomography (SPECT) combined with computed tomography (CT) was introduced as a hybrid SPECT/CT imaging modality two decades ago. The main advantage of SPECT/CT is the increased specificity achieved through a more precise localization and characterization of functional findings. The improved diagnostic accuracy is also associated with greater diagnostic confidence and better inter-specialty communication.

METHODS

This review presents a critical assessment of the relevant literature published so far on the role of SPECT/CT in a variety of clinical conditions. It also includes an update on the established evidence demonstrating both the advantages and limitations of this modality.

CONCLUSIONS

For the majority of applications, SPECT/CT should be a routine imaging technique, fully integrated into the clinical decision-making process, including oncology, endocrinology, orthopaedics, paediatrics, and cardiology. Large-scale prospective studies are lacking, however, on the use of SPECT/CT in certain clinical domains such as neurology and lung disorders. The review also presents data on the complementary role of SPECT/CT with other imaging modalities and a comparative analysis, where available.

Quantitative Research of 11C-CFT and 18F-FDG PET in Parkinson's Disease: A Pilot Study With NeuroQ Software

Dopamine transporter (DAT) and glucose metabolism imaging have been applied in the diagnosis of Parkinson’s disease (PD). We explored the possibility of evaluating for PD with NeuroQ software by analyzing ¹¹C-2β-carbomethoxy-3β-(4-fluorophenyl) tropane (¹¹C-CFT) and ¹⁸F-FDG PET/CT. We retrospectively analyzed brain ¹¹C-CFT and ¹⁸F-FDG PET/CT of 38 patients with parkinsonism, including 20 with PD, 10 with multiple system atrophy (MSA) and 8 with essential tremor (ET), and compared them with the PET/CT of 11 normal healthy controls (NC). PD patients were divided into mild and moderate-severe grade according to the Hoehn-Yahr (H&Y) scale. The ¹¹C-CFT uptake in the caudate nuclei (CN) and putamen (Pu) normalized with cerebellum (CN/Cb and Pu/Cb) were obtained with a manual method and NeuroQ software, and their diagnostic performance was compared.¹⁸F-FDG uptake of specific regions was also obtained with NeuroQ, and the enhancement effect for the differential diagnosis was evaluated. There was significant agreement between the manual method and the NeuroQ method for ¹¹C-CFT uptake by CN (r²= 0.680) and Pu (r²= 0.770). ¹¹C-CFT uptake by CN and Pu in PD and MSA patients was significantly lower compared to NC and ET patients. The cutoffs of CN/Cb and Pu/Cb for the distinction between PD and NC were 1.71 and 2.20, respectively. No difference in uptake ratios occurred between PD and MSA. ¹⁸F-FDG uptake by the pons and cerebellum in the MSA group was markedly decreased. It was highly accurate in distinguishing between PD and MSA when combined with analysis of ¹¹C-CFT uptake. Pu/Cb decreased significantly in mild grade PD compared to NC group (1.92 ± 0.33 vs. 2.82 ± 0.43); however no statistically significant decrease in CN/Cb was observed until moderate-severe grade PD (1.43 ± 0.11 vs. 2.23 ± 0.36). In early asymmetric PD, a statistically significant difference could be seen with Pu/Cb between the symptomatic and asymptomatic side (2.17 ± 0.30 vs. 1.95 ± 0.22). ¹¹C-CFT and ¹⁸F-FDG PET/CT can be analyzed quantitatively with NeuroQ software, which provides an accurate method for the diagnosis and severity evaluation of PD.

Semiquantitative analysis using standardized uptake value in 123I-FP-CIT SPECT/CT

PURPOSE

To evaluate potential of a semiquantitative method using standardized uptake value (SUV) in ¹²³I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (¹²³I-FP-CIT) single photon emission computed tomography/computed tomography (SPECT/CT) compared with specific binding ratio (SBR).

MATERIALS AND METHODS

First, we performed a phantom study to validate the accuracy of measuring SUV. 52 patients (25 male, 27 female; mean age of 75.1-year-old; 40 and 12 patients with neurodegenerative diseases with or without presynaptic dopaminergic deficits, respectively) were enrolled in a retrospective study. We measured SBR, maximum SUV, peak SUV, mean SUV, and striatum-to-background ratio of SUV (SUV_ratio) for striatum with lower ¹²³I-FP-CIT uptake using commercial software. We calculated Pearson's correlation coefficient between SBR and SUV. We also calculated the sensitivity, specificity, and accuracy of each parameter for differential diagnosis.

RESULTS

The phantom study revealed errors of <10% between theoretical and actual SUVs. Although there were significant correlations between SBR and all SUV-based parameters, SUV_ratio showed the most strong correlation with SBR (r = 0.877, p < 0.001). However, diagnostic capability of SUV_ratio (cutoff = 2.35) yielded to that of SBR (cutoff = 3.90) for diagnosing neurodegenerative diseases with presynaptic dopaminergic deficits (sensitivity of 85.0% vs 92.5%, specificity of 100% vs 91.7%, and accuracy of 88.5% vs 92.3%, respectively).

CONCLUSION

SBR is a promising parameter to aid differential diagnosis of neurodegenerative diseases with or without presynaptic dopaminergic deficit. Although technically acceptable, SUV may not be superior to SBR when clinically applied in ¹²³I-FP-CIT SPECT/CT.

I-123 DaTscan SPECT Brain Imaging in Parkinsonian Syndromes: Utility of the Putamen-to-Caudate Ratio

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.

Interpreting 123I-ioflupane dopamine transporter scans using hybrid scores

BACKGROUND

Dopamine transporter (DaT) ¹²³I-FP-CIT scans most commonly are interpreted visually. Alternatively, absolute quantitation of radiopharmaceutical uptake may improve scan accuracy. However, neither approach accomodates dependence of striatal uptake on age and gender. We investigated whether demographic indexing of visual and numerical variables improve discrimination of patients with essential tremor (ET), Parkinson's disease (PD), and dementia with Lewy bodies (DLB).

METHODS

Data of 132 consecutive patients undergoing DaT SPECT scans were reviewed retrospectively. The clinical impression in the latest neurology note was utilized as the final clinical diagnosis. Caudate and putamen specific binding ratio (PSBR) were computed. ¹²³I calibration phantoms were constructed to enable absolute quantitation of putamen radiopharmaceutical uptake. A single experienced nuclear medicine physician graded visual certainty on a 3-level scale. Demographic indexing normalized metrics to published normal PSBR values. Methods were compared by simultaneous ROC analyses to identify the technique of maximal accuracy.

RESULTS

Thirty-four patients (26%) were diagnosed with ET, 85 (64%) with PD, 6 (5%) with multiple system atrophy, and 7 (5%) with DLB. For discriminating DLB from PD, visual analysis was significantly less specific and accurate than the other techniques. However, indexing significantly improved specificity and accuracy of visual scores, such that indexed visual scores were statistically equivalent to all other methods. Indexed PSBR yielded essentially the same results as non-indexed PSBR, for which highest overall test efficacy was achieved.

CONCLUSIONS

Our results in this small series of patients with DLB suggest that if ¹²³I-FP-CIT visual scores are to be used to discriminate DLB from other neurologic disorders, demographic indexing should be applied. However, best results overall are obtained using quantified parameters, regardless of whether or not demographic indexing is applied to these values.

Semi-quantitative dopamine transporter standardized uptake value in comparison with conventional specific binding ratio in [123I] FP-CIT single-photon emission computed tomography (DaTscan)

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.

Quantitative evaluation of the tracer distribution in dopamine transporter SPECT for objective interpretation

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.

Japanese multicenter database of healthy controls for [123I]FP-CIT SPECT

PURPOSE

The aim of this multicenter trial was to generate a [¹²³I]FP-CIT SPECT database of healthy controls from the common SPECT systems available in Japan.

METHODS

This study included 510 sets of SPECT data from 256 healthy controls (116 men and 140 women; age range, 30-83 years) acquired from eight different centers. Images were reconstructed without attenuation or scatter correction (NOACNOSC), with only attenuation correction using the Chang method (ChangACNOSC) or X-ray CT (CTACNOSC), and with both scatter and attenuation correction using the Chang method (ChangACSC) or X-ray CT (CTACSC). These SPECT images were analyzed using the Southampton method. The outcome measure was the specific binding ratio (SBR) in the striatum. These striatal SBRs were calibrated from prior experiments using a striatal phantom.

RESULTS

The original SBRs gradually decreased in the order of ChangACSC, CTACSC, ChangACNOSC, CTACNOSC, and NOACNOSC. The SBRs for NOACNOSC were 46% lower than those for ChangACSC. In contrast, the calibrated SBRs were almost equal under no scatter correction (NOSC) conditions. A significant effect of age was found, with an SBR decline rate of 6.3% per decade. In the 30-39 age group, SBRs were 12.2% higher in women than in men, but this increase declined with age and was absent in the 70-79 age group.

CONCLUSIONS

This study provided a large-scale quantitative database of [¹²³I]FP-CIT SPECT scans from different scanners in healthy controls across a wide age range and with balanced sex representation. The phantom calibration effectively harmonizes SPECT data from different SPECT systems under NOSC conditions. The data collected in this study may serve as a reference database.