Abnormal SPECT Research Articles

Optimal DaTQUANT Thresholds for Diagnostic Accuracy of Dementia with Lewy Bodies (DLB) and Parkinson's Disease (PD).

Background: Quantitative thresholds are helpful to define an abnormal DaT SPECT in patients with suspected nigrostriatal degenerative diseases (NSDD). The optimal DaTQUANT threshold for diagnostic accuracy of DaT SPECT across combined movement and cognitive disorder populations has been previously described. Methods: We established optimal DaTQUANT thresholds that enhance the discrimination between dementia with Lewy bodies (DLB) and non-DLB dementia types, as well as between Parkinsonian syndromes (PS) and conditions not characterized by nigrostriatal degeneration (non-PS). Results: Data from a total of 303 patients were used in this retrospective analysis. Posterior putamen of the more affected hemisphere (MAH) was shown to be an accurate single-variable predictor for both DLB and PS and was comparable to the most accurate multi-variable models. Conclusions: Automated quantification with DaTQUANT can accurately aid in the differentiation of DLB from non-DLB dementias and PS from non-PS. Optimal thresholds for assisting a diagnosis of DLB are striatal binding ratio (SBR) ≤ 0.65, z-score ≤ -2.36, and a percent deviation ≤ -0.54 for the posterior putamen of the MAH. Optimal posterior putamen thresholds for assisting a diagnosis of PS are SBR ≤ 0.92, z-score ≤ -1.53, and a percent deviation ≤ -0.33, which are similar to our previously reported posterior putamen threshold values using a blended patient pool from multiple study populations.

Whole brain pattern of iron accumulation in REM sleep behavior disorder.

Isolated REM sleep behavior disorder (iRBD) is an early stage of synucleinopathy with most patients progressing to Parkinson's disease (PD) or related conditions. Quantitative susceptibility mapping (QSM) in PD has identified pathological iron accumulation in the substantia nigra (SN) and variably also in basal ganglia and cortex. Analyzing whole-brain QSM across iRBD, PD, and healthy controls (HC) may help to ascertain the extent of neurodegeneration in prodromal synucleinopathy. 70 de novo PD patients, 70 iRBD patients, and 60 HCs underwent 3 T MRI. T1 and susceptibility-weighted images were acquired and processed to space standardized QSM. Voxel-based analyses of grey matter magnetic susceptibility differences comparing all groups were performed on the whole brain and upper brainstem levels with the statistical threshold set at family-wise error-corrected p-values <.05. Whole-brain analysis showed increased susceptibility in the bilateral fronto-parietal cortex of iRBD patients compared to both PD and HC. This was not associated with cortical thinning according to the cortical thickness analysis. Compared to iRBD, PD patients had increased susceptibility in the left amygdala and hippocampal region. Upper brainstem analysis revealed increased susceptibility within the bilateral SN for both PD and iRBD compared to HC; changes were located predominantly in nigrosome 1 in the former and nigrosome 2 in the latter group. In the iRBD group, abnormal dopamine transporter SPECT was associated with increased susceptibility in nigrosome 1. iRBD patients display greater fronto-parietal cortex involvement than incidental early-stage PD cohort indicating more widespread subclinical neuropathology. Dopaminergic degeneration in the substantia nigra is paralleled by susceptibility increase, mainly in nigrosome 1.

Unexpectedly abnormal PICNIR test and brain SPECT even in the grandson of a patient with dementia

Unexpectedly abnormal PICNIR test and brain SPECT even in the grandson of a patient with dementia

Cortical excitability in patients with REM sleep behavior disorder with abnormal TRODAT-1 SPECT scan: an insight into prodromal Parkinson's disease.

REM Sleep Behavior Disorder (RBD) has been highlighted to identify a patient with prodromal Parkinson's disease (PD). Although many studies focus on biomarkers to predict an RBD patient's evolution from prodromal PD to clinical PD, the neurophysiological perturbation of cortical excitability has not yet been well elucidated. Moreover, no study describes the difference between RBD with and without abnormal TRODAT-1 SPECT. By measuring the amplitude of motor evoked potentials (MEP), the cortical excitability changes after transcranial magnetic stimulation (TMS) were evaluated in 14 patients with RBD and eight healthy controls (HC). Seven of the 14 patients with RBD showed abnormal TRODAT-1 (TRA-RBD), and seven were normal (TRN-RBD). The tested parameters of cortical excitability include resting motor threshold (RMT), active motor threshold (AMT), short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), contralateral silence period (CSP), and input-output recruitment curve. The RMT and AMT showed no difference among the three studied groups. There was only SICI at inter-stimuli-interval 3 ms revealing group differences. The TRA-RBD demonstrated significant differences to HC in these aspects: decreased SICI, increased ICF, shortening of CSP, and augmented MEP amplitude at 100% RMT. Moreover, the TRA-RBD had a smaller MEP facilitation ratio at 50% and 100% of maximal voluntary contraction when compared to TRN-RBD. The TRN-RBD did not present any difference to HC. We showed that TRA-RBD shared similar cortical excitability changes with clinical PD. These findings would provide further insight into the concept that RBD is the highly prevalent entity in prodromal PD.

Quantitative assessment of 99mTc-methylene diphosphonate bone SPECT/CT for assessing bone metastatic burden and its prognostic value in patients with castration-resistant prostate cancers: initial results in a single-center retrospective study

To evaluate the prognostic value of the quantitative assessment of 99mTc-methylene diphosphonate (99mTc-MDP) bone SPECT/CT in castration-resistant prostate cancer (CRPC) patients with bone metastases. A total of 103 patients who underwent 99mTc-MDP bone SPECT/CT imaging from the neck to the proximal femur were included. First, in 65 patients without bone metastases, the normal range of standardized uptake value (SUV) of non-pathological bone was evaluated to determine an SUV threshold to reliably exclude most normal osseous activity. Then, in 38 CRPC patients with bone metastases, lesion uptake volume (LUV), which is the extracted volume of bone metastases exhibiting high accumulation above the SUV threshold, was calculated. The relation between LUV and prostate-related mortality was statistically evaluated. Based on the SUV measurements of non-pathological bones, the optimal SUV threshold, which defines abnormal bone SPECT uptake, was determined to be 8. Median LUV was 39mL (interquartile range 4.0-104.3mL) in the CRPC subjects with bone metastases. Kaplan-Meier survival analysis showed a significant relation between prostate cancer-specific survival and LUV (cut-off value, 19.95mL; P = 0.001). Multivariate analysis revealed LUV as an independent prognostic factor for the survival (P = 0.008, hazard ratio 23.424). Global chi-square test showed that LUV had significant incremental prognostic value in addition to prostate-specific antigen and the interval from progression to CRPC until bone SPECT/CT (P = 0.022). Quantitative assessment of 99mTc-MDP bone SPECT images can provide valuable prognostic information in CRPC patients with bone metastases.

Different z-score cut-offs for striatal binding ratio (SBR) of DaT SPECT are needed to support the diagnosis of Parkinson's Disease (PD) and dementia with Lewy bodies (DLB).

A cut-off of -2 z-score for striatal or putaminal SBR has been to date arbitrarily used to define an abnormal DaT SPECT in patients with suspected neurodegenerative parkinsonism. We aimed to experimentally identify the most accurate z-score cut-offs for SBR of striatal and substriatal regions to independently discriminate PD and DLB, with respect to essential tremor (ET) and Alzheimer's disease (AD) respectively. Two-hundred twenty-five patients undergoing DaT SPECT were enrolled (seventy-five de novo PD, eighty ET, fifty DLB, and twenty AD). Semiquantification was computed by means of Datquant® software which returns measures of striatal SBR and z-scores with respect to 118 healthy volunteers belonging to the Parkinson's Progression Markers Initiative (PPMI). ROC analysis was used to identify most accurate cut-offs for z-score for striatum and substriatal regions (clinical diagnosis at follow-up as gold standard). Posterior putamen of the most affected hemisphere (MAH) with a z-score cut-off of - 1.27 demonstrated the highest accuracy to differentiate between PD and ET (sensitivity 0.97, specificity 0.94). The whole putamen (z-score cut-off - 0.96) was the most accurate parameter to support the diagnosis of DLB (sensitivity 0.74, specificity 0.95). Putamen to caudate ratio was accurate to detect PD (especially in early stages) while not DLB patients. We experimentally demonstrated that different substriatal regions and cut-offs for z-score of SBR should be considered to support the diagnosis of either PD or DLB. The identified less conservative cut-offs showed higher sensitivity without a measurable reduction in specificity with respect to the arbitrary - 2 z-score.

Baseline and Longitudinal Ioflupane SPECT Findings in DLB and MCI‐LB

AbstractBackgroundReduced striatal uptake on ioflupane SPECT is considered an indicative biomarker for Dementia with Lewy Bodies (DLB), and has been proposed as an indicative biomarker for Mild Cognitive Impairment with Lewy Bodies (MCI‐LB). Little data exists on the profile of uptake on key striatal regions of interest (ROIs) in DLB or MCI‐LB.MethodParticipants with DLB or MCI‐LB at baseline based on the presence of ≥2 core clinical DLB features, and ≥2 ioflupane SPECT scans performed approximately annually, were identified from the Mayo ADRC database. Minimum brain laterality z‐score values for the putamen (whole, anterior and posterior), caudate and striatum were determined using DaTQUANT 2 software. Baseline clinical and scan data was used for all analyses, and the annualized minimum putamen z‐change was determined on serial scans. The scan was considered abnormal if the minimum putamen z‐score was &lt;‐0.98 based on clinicopathologic data.Result27 participants were included (21 DLB and 6 MCI‐LB, 96% male). Compared to MCI‐LB, DLB had a lower mean MoCA score and a trend toward a higher UPDRS score compared to MCI‐LB; there were no statistically significant differences in age, sex, onset age or duration of cognitive decline, or presence of other core DLB features. The majority (89%) had an abnormal scan at baseline. All ROI z‐scores showed the expected general trend of DLB&lt;MCI‐LB, and the annualized z‐change was more negative in DLB, but none of the findings reached statistical significance.ConclusionThese findings suggest in MCI‐LB and DLB that 1) an abnormal ioflupane SPECT scan is frequently present at diagnosis, 2) z‐scores become more negative over time, and 3) the annualized z‐change is similar. Similar findings in larger cohorts would support the use of ioflupane SPECT as a biomarker in both MCI‐LB and DLB clinical trials.

Global longitudinal strain and its association with quantitative and qualitative analyses of myocardial perfusion correlate in patients with abnormal SPECT results

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND Global longitudinal strain (GLS) is being used more commonly in the evaluation of patients with ischemic heart disease (IHD). Even though GLS is known to be associated with infarct size, its relationship with parameters derived from myocardial perfusion studies (MPS) has not been explored enough. AIMS We assessed the correlation of GLS measured with echocardiography with quantitative and qualitive analyses parameters of SPECT-MPS, particularly stress and rest total perfusion deficits (TPDS and TPDR) and summed stress and summed rest scores (SSS and SRS) respectively. METHODS A cross-sectional cohort of patients classified with an abnormal nuclear medicine result using SPECT were tested with doppler echocardiography in a center of reference in Mexico City. Pearson correlation tests and polynomial regression models were used to extract the correlation coefficient and the explained variability for each variable. RESULTS 122 subjects with abnormal nuclear medicine results were assessed. 87 (71.3%) were male with a mean left ventricular GLS of -16 (±5), SRS of 12.9 (±14.5), SSS of 18 (±15.8), TPDR of 12 (±14.3) and TPDS of 17.7 (±15.6). We observed a negative cubic adjusted correlation between GLS and TPDR (r = 0.501, 95% CI: 0.336-0.637, p= &amp;lt;0.001), TPDS (r = 0.470, 95% CI: 0.300-0.612, p= &amp;lt;0.001), SRS (r = 0.472, 95% CI: 0.302-0.613, p= &amp;lt;0.001) and SSS (r = 0.460, 95% CI: 0.288-0.603, p= &amp;lt;0.001). CONCLUSION GLS has a moderate cubic correlation with a negative leading coefficient with TPDR, TPDS, SRS and SSS. This data suggests that GLS may be an adequate parameter for assessing patients with IHD. Abstract Figure. Scatter plot with regression model

Association between T wave morphology parameters and abnormal cardiac SPECT imaging

BackgroundT-wave morphology dispersion (TMD) described the electrocardiographic T-wave heterogeneity during a single cardiac cycle. Total cosine R-to-T (TCRT) is the average of the cosines of the angles between the QRS and T vectors on the ECG. We examine the predictive value of TMD and TCRT calculation to assess abnormal myocardial perfusion. MethodsRetrospective single center cohort study including all patients referred for evaluation of ischemia by myocardial SPECT scanning with no known history of ischemic heart disease, from 1 January 2019 to 31 December 2019. Study endpoint was the correlation between the calculated TMD and TCRT values and detection of myocardial injury or ischemia by myocardial SPECT. ResultsAmong 606 patients, calculated TCRT was 0.401 ± 0.53 for the normal group and 0.283 ± 0.62 for the abnormal group (p = 0.007). Measured TMD was 22.9 ± 16.6 degrees (p < 0.001) in the normal group, compared to 31.5 ± 22.8 degrees (p < 0.001) for the abnormal group. ConclusionsThe results demonstrate a correlation between the decreased TCRT values and increase TMD and myocardial ischemia seen in SPECT results. The TCRT and TMD can be used as simple and non-invasive markers to predict abnormal SPECT results and ischemic heart disease in patients with no known cardiac history.

Pretest models for predicting abnormal stress single-photon emission computed tomography myocardial perfusion imaging

BackgroundThe frequency of abnormal stress SPECT myocardial perfusion imaging (MPS) decreased over the past decades despite an increase in the prevalence of cardiovascular risk factors. These findings strengthen the need to develop more effective strategies for appropriately referring patients with suspected coronary artery disease (CAD) to cardiac imaging. The aim of this study was to develop pretest assessment models for predicting abnormal stress MPS. MethodsWe included 5,601 consecutive patients with suspected CAD, who underwent stress MPS at our academic center. Two different models were considered: a basic model including age, gender, and anginal symptoms; and a clinical model including also diabetes, hypertension, hypercholesterolemia, smoking, and family history of CAD. ResultsIn patients with abnormal MPS, the basic model classified more than 75% of patients as intermediate risk, whereas only 23% were incorrectly classified as low risk. In patients with normal MPS, 45% were correctly classified as low risk and none as high risk. Basic and clinical models had a limited discriminating capacity (area under the receiver operating characteristic curve 0.644 for basic model and 0.647 for clinical model) between individuals with and without abnormal stress MPS. The decision curve analysis demonstrates a high net benefit across a range of threshold probabilities from ~ 15% to ~30% for both models. ConclusionsA pretest risk stratification based on traditional cardiovascular risk factors has a limited value for predicting an abnormal stress MPS in patients with suspected CAD. However, selecting a proper threshold probability enhances the appropriateness of referral to stress MPS.

Assessing the prevalence and predicting factors of an abnormal gated myocardial perfusion SPECT in asymptomatic patients with type 2 diabetes.

Considering the significant prevalence of silent myocardial ischemia and its related morbidity and mortality in asymptomatic type 2 diabetic patients, it is not well known whether early screening with MPI is cost-effective and predicting factors are not well elucidated. This was a cross-sectional study including 63 asymptomatic patients with type 2 diabetes mellitus (T2DM), with normal ECG and ejection fraction. Patients with any history of documented valvular, congestive or ischemic heart disease, renal or hepatic failure were excluded. At first all patients were interviewed and checked for risk factors and then patients underwent a two-day rest/stress 99mTc-MIBI gated MPI SPECT. Data was assessed by QPS/QGS and 4DM software and evaluated by a nuclear medicine specialist with summed stress score (SSS) of more than 4 defined as CAD. There were 42 females (67%) and 21 males (33%), with a mean age of 61.33 ± 6.98years and 7.97 ± 4.86years history of T2DM. CAD was detected in 26 (41.3%) patients and was significantly associated with male gender, smoking and requiring insulin therapy (P-value = 0.019, 0.046, 0.05, respectively). A significant association was found between the duration of diabetes, especially when > 15years, and the probability of having CAD. Multivariable logistic regression revealed that smoking; male gender and diabetes duration were the strongest independent predictors of abnormal MPI results. We found a high (46%) prevalence of abnormal stress MPI SPECT in patients with type 2 diabetes mellitus, despite being asymptomatic. Asymptomatic patients with a history of smoking, long duration of diabetes, being under insulin treatment and male gender might benefit from MPI for early detection of silent ischemia.

Single photon emission computed tomography myocardial perfusion imaging in patients with moderate to severe psoriosissis.

Psoriasis is a chronic inflammatory disorder with an increased risk for coronary artery disease (CAD). This retrospective study aimed to evaluate the rate of myocardial ischaemia in patients with psoriasis subjected to myocardial perfusion imaging (MPI). Twelve patients with moderate to severe psoriasis that had MPI were compared to 395 MPIs randomly retrieved from our MPIs pool data. All patients had a [99mTc]tetrofosmin stress - rest single-photon emission computer tomography ([99mTc]SPECT). Summed difference scores (SDS) were calculated for stress (SSS), rest (SRS) and their difference (SDS = SSS - SRS). There was no significant difference in the frequency of abnormal MPI SPECT outcomes between patients with vs. without psoriasis (6/12 vs 214/395 respectively; p = 0.778). From the evaluation of SSS, SRS and SDS, only the SDS scores of inadequately compensated resting perfusion defects were significantly lower in patients with psoriasis (p = 0.012). Patients with moderate-to-severe psoriasis had a similar rate of abnormal SSS scans compared to control patients. However, the SDS scans were significantly lower in patients with psoriasis indicating compromised reversibility of resting perfusion defects. Larger controlled studies are needed to verify these observations.

Vitamin D Deficiency as a Risk Factor for Myocardial Ischemia

Background and Objectives: Vitamin D (Vit D) deficiency has been implicated in various conditions, including cardiovascular disease. The purpose of this retrospective study was to investigate the incidence of patients with myocardial ischemia in relation to their serum levels of vitamin D. Materials and Methods: A 64-month search (January 2016 to April 2021) in our database of the Nuclear Medicine Laboratory revealed 113 patients who had both myocardial perfusion imaging with single photon emission computed tomography (MPI SPECT) and Vit D measurements. MPI SPECT obtained myocardial images during both stress (summed stress score, SSS) and rest (summed rest score, SRS). Abnormal MPI SPECT was when the SSS was ≥4. Vit D was determined by radioimmunoassay (RIA). Patients with Vit D values <10 ng/mL, 10–29 ng/mL and ≥30 ng/mL were defined as having a deficiency, insufficiency and sufficiency, respectively. Results: Among patients, 46/113 (40.7%) were male and 67/113 (59.3%) were female. Abnormal MPI was found in 58/113 (51.3%) patients. Vit D deficiency was noted in 20/113 (17.7%) patients, insufficiency in 86/113 (76.1%) patients, and normal Vit D was noted in only 7/113 (6.2%) patients. Sixteen of the 20 patients (80%) with Vit D deficiency, and 38/86 (44.2%) with insufficiency had an abnormal MPI SPECT. In contrast, only 1/7 (14.3%) patients with sufficient Vit D levels had an abnormal MPI SPECT. The Mann-Whitney U-test showed that ischemia reduced the values of Vit D. Correlation analysis showed a negative association of Vit D levels with SSS (rho = −0.232, p = 0.014) and SRS (rho = −0.250, p = 0.008). Further evaluation with a Vit D cut off 20 ng/mL retrieved no statistical significance. Finally, Vit D and gender were independently associated with myocardial ischemia. Conclusions: Low Vit D levels may represent a risk factor for myocardial ischemia.

Incremental prognostic value of SPECT CT based visual calcium score burden for outcomes prediction

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): Astellas Pharma US Background Coronary calcium is an important non-perfusion finding on SPECT CT attenuation correction (AC) and has been shown to help decrease equivocal interpretation and identifying atherosclerosis despite normal perfusion. Although correlations with measured calcium score have been good, an easy visual calcium score (VCS) for CT AC calcium and its prognostic value has not been well established. Purpose We aimed to evaluate the role of VCS calculated from low-dose CT for AC in predicting outcomes stratified by SPECT (normal versus abnormal). Methods A retrospective data review of patients who underwent cardiac SPECT CT at our center from January 2009 -August 2012 with a mean follow up of 4.5 years. Baseline characteristics and outcomes were collected. VCS scoring was established as follows and was completed on all scans by three senior cardiology fellows. When not congruent, consensus with third reader was established. Presence of visual calcium in any of the following arteries was recorded as a score of 1 with VCS range 0-6: left main, left anterior descending, left circumflex, right coronary, ascending aorta, and descending thoracic aorta. Subjects were divided into 3 groups based on the VCS of &amp;lt;2, 2-4, and &amp;gt;4. Normal versus abnormal SPECT was defined as summed stress score/summed difference score of &amp;lt;4/&amp;lt;2 and &amp;gt; =4/&amp;gt; =2 respectively. Major adverse cardiac events (MACE) defined as presence of heart failure, myocardial infarction, and/or cardiac death. Results 538 consecutive patients with SPECT CT were evaluated. Mean age was 63.3 years with 54% females. There were 463 (86%) normal SPECT and 75 (14%) abnormal SPECT. Using VCS, there was a statistically significant increase in the percentage of MACE over the period of follow-up with step wise increase in VCS severity in normal SPECT group (p-value = 0.001), although not significant in the abnormal MPI group (Figure 1). There was a higher mortality with increasing VCS in both normal and abnormal SPECT (p= &amp;lt;0.001 and p = 0.014 respectively). Using a multivariate logistic regression model in patients with normal SPECT, there were higher odds of death (OR 1.26) with every 1 point of VCS increase controlling for age, sex, baseline heart rate, history of dialysis, diabetes and stroke (95% confidence interval 1.09, 1.45; p-value = 0.002). Conclusion This study highlights the importance of factoring CT AC calcium in risk assessment of SPECT. CT AC calcium represents an easily available and important adjunctive risk marker during SPECT interpretation. A simple VCS as derived in this study can help with the additive risk stratification in both normal and abnormal SPECT and is of an incremental prognostic value for MACE. Clinicians interpreting SPECT should include coronary calcification on AC CT routinely in reports to help management and prognostication decisions. Our study shows that VCS can be a simple easily adopted tool for consistent reporting.

Value of coronary artery calcium score in reporting SPECT versus PET myocardial perfusion imaging

Abstract Funding Acknowledgements Type of funding sources: None. Background Although it is well known that coronary artery calcium score (CACS) adds value to reporting myocardial perfusion imaging (MPI) SPECT, its added value to reporting PET MPI is not clear. Purpose Hence, our aim was determine the value of adding CACS in the assessment of PET MPI and SPECT MPI and compare the value between both modalities in a low-risk population. Methods We retrospectively included 412 patients, half of them underwent SPECT with CACS and half underwent Rubidium-82 PET with CACS. We created comparable groups using propensity matching, where the PET group was 1:1 matched to a comparable SPECT group, obtained from a large cohort of 4018. Next, we created two types of image sets for the 412 included patients: MPI-only and MPI + CACS. Two experienced physicians interpreted the 824 images as normal, equivocal or abnormal for ischemia or irreversible defects and were blinded for the used modality. In addition, annualized event rates, defined as the occurrence of all-cause death, non-fatal myocardial infarction or revascularization therapy (PCI or CABG), were compared between the PET and SPECT groups using a follow-up period of 30 months. Results The percentage of scans interpreted as normal was 8% higher with PET-only than with SPECT-only (89 vs 80%, respectively, p = 0.014). Adding CACS to SPECT increased the percentage of scans interpreted as normal from 80% to 86% (p = 0.014), whereas this effect was absent for PET (p = 0.77). Adding CACS reduced the frequency of equivocal scans from 12% and 6% to 0% for both SPECT and PET, respectively. Furthermore, adding CACS resulted in 5% more abnormal interpreted scans for both PET (4.9 to 10%, p = 0.003) and SPECT (8.7 to 14%, p = 0.04). The annualized event rate was 2.7% for the SPECT and 3.5% for the PET group (p = 0.58). The annualized event rates for images interpreted as normal were comparable between all four types of image sets and varied between 0.7-2.0% (p &amp;gt; 0.084). The annualized event rate for equivocal and abnormal scans was higher for PET-only (23%) compared to SPECT-only (4.8%, p &amp;lt; 0.001). Moreover, the event rate for equivocal and abnormal SPECT + CACS (8.6%) was also higher than for SPECT-only (4.8%, p = 0.04), whereas this difference was absent for PET (p = 0.07). Conclusion Adding CACS increases the percentage of scans interpreted as normal for SPECT MPI while the event rate remained unchanged. Adding CACS to PET did not influence the percentage of scans interpreted as normal, limiting the effect of adding CACS to PET in a low-risk population.

Long-term prognosis of zero coronary artery calcium score in symptomatic low to intermediate risk patients

Abstract Funding Acknowledgements Type of funding sources: None. Purpose/background Absence of coronary artery calcium (CAC) has shown an excellent long-term prognosis with a low number of events in asymptomatic patients. However, long-term prognosis in stable symptomatic patients undergoing SPECT MPI with a zero CAC score remains unknown. Methods We retrospectively analyzed 1600 low- to intermediate risk symptomatic patients referred for clinically indicated cardiac SPECT/CT imaging with a CAC score of zero. Long-term follow-up data were collected for the occurrence of all-cause mortality and major adverse cardiac events (MACE: any revascularization, non-fatal myocardial infarction or cardiac death). Results The mean age was 54.7 ± 11 years and 71% were female. More than half of the patients (51%) had 2 or more traditional risk factors, mainly a positive family history (55%) and/or hypertension (49%). Overall 12% had perfusion abnormalities, 98% of them were mild. During a mean follow-up of 8.6 ± 1.9 years MACE occurred in 42 patients (0.3% per year) and 85 patients died (0.6% per year). The predominant cause of death was cancer (40%). Cox proportional hazard model revealed that increasing age (HR: 1.05, 95% CI: 1.02-1.09) and current smoking status (HR: 3.58, 95% CI: 1.72-7.37) were independent predictors of MACE. Pre-test probability (HR: 1.52, 95% CI: 0.82-2.82) and abnormal SPECT result (HR: 1.72, 95% CI: 0.88-3.37) were not associated with an increased risk of MACE. Conclusion Overall, stable symptomatic patients with a low-to intermediate risk and a CAC score of 0 have a) low likelihood of abnormal SPECT, and b) excellent long-term prognosis of 0.3%/year irrespective of baseline pre-test probability and SPECT abnormalities. These findings support notion of CAC as gatekeeper for appropriate patient selection to avoid un-necessary downstream testing.

Why Defining The Anatomy Is Important: CT Coronary Angiogram Following An Abnormal Spect Identifies An Unexpected Finding

Introduction: A 73-year-old male patient presented with atypical chest pain radiating to the back of one-week duration. Initial work-up included negative cardiac enzymes, electrocardiogram without signs of ischemia, and a non-contrast-enhanced CT of abdomen and pelvis for concern for renal colic which showed moderate atherosclerotic plaque in the abdominal aorta. The patient underwent an exercise SPECT which showed ST depression in the inferolateral leads with exercise and a small, fixed defect in the apex and inferior region, overall suggestive of intermediate risk for cardiovascular mortality.

Impact of the Charlson Comorbidity Index score on risk prediction by single-photon emission computed tomography myocardial perfusion imaging following myocardial infarction.

BackgroundComorbidity is common among patients with myocardial infarction (MI). We examined whether comorbidity level modified the single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI)-based prediction of 5-year risk of MI and all-cause death in patients with MI.MethodsThis cohort study included patients with prior MI having a SPECT MPI at Aarhus University Hospital, Denmark, 1999–2011. Using nationwide registries, we obtained information on comorbidity levels (low, moderate, and severe) and outcomes. We computed risk and hazard ratios (HRs) with 95% confidence intervals (CIs) for MI and all-cause death, comparing normal (no defects) versus abnormal scan (reversible and/or fixed defects) using Cox regression adjusting for sex, age, and comorbidity level.ResultsWe identified 1,192 patients with MI before SPECT MPI. The 5-year risk for patients with normal versus abnormal scans were 11.7% versus 18.3% for MI, and 8.0% versus 13.2% for all-cause death, respectively. The overall 5-year adjusted HR (aHR) of MI was 1.56 (95% CI: 1.09–2.21), 1.33 (95% CI: 0.82–2.15) with low comorbidity, 1.39 (95% CI: 0.68–2.83) with moderate comorbidity, and 2.53 (95% CI: 1.14–5.62) with severe comorbidity. Similarly, the 5-year aHR for all-cause death was 1.39 (95% CI: 0.90–2.14) overall; 2.33 (95% CI: 0.79–6.84) with low comorbidity, 2.05 (95% CI: 0.69–6.06) with moderate comorbidity, and 1.07 (95% CI: 0.64–1.80) with severe comorbidity.ConclusionWe conclude that comorbidity level may modify the 5-year risk prediction associated with an abnormal SPECT MPI scan in patients with previous MI.

Revision of Diagnosis in Early Parkinsonism with Abnormal Dopamine Transporter Imaging.

In patients with early parkinsonism, misdiagnosis may occur in >30% of cases. This can have detrimental consequences clinically and in clinical trials. Dopamine transporter (DAT) SPECT imaging can help improve diagnostic accuracy. To describe characteristics of individuals initially diagnosed with idiopathic Parkinson's disease (iPD) and with abnormal DAT SPECT imaging who had a change in diagnosis on follow-up. Data were obtained from the biomarker study Parkinson's Progression Markers Initiative (PPMI). PPMI is a multicenter, observational study that enrolled 423 individuals with a diagnosis of iPD of ≤2 years duration and with abnormal DAT SPECT imaging. Participants were assessed at least annually, and diagnosis was documented by the site neurologist. Characteristics of those that had a change in diagnosis were compared to those with stable diagnosis. 390 subjects were included. Eight (2%) had a change in diagnosis. The diagnosis was changed to multiple system atrophy in 5 cases, dementia with Lewy bodies in 2, and corticobasal degeneration in 1. Revision of diagnosis occurred 2-5.2 years from enrollment. Mean motor score was higher (26.9 vs 20.6; p = 0.01), DAT binding lower (1.056 vs 1.406; p = 0.01), genetic risk score lower (-0.016 vs -0.022; p = 0.0470), and olfaction score higher (28.75 vs 22.05; p = 0.03) in those whose diagnosis changed compared to those who did not. Diagnosis remained stable in most individuals with early parkinsonism diagnosed with iPD and with abnormal DAT imaging. A small number had a revision in diagnosis. Clinical and biomarker abnormalities were greater at baseline in those whose diagnosis changed.

Low-dose dual-isotope procedure planed for myocardial perfusion CZT-SPECT and assessed through a head-to-head comparison with a conventional single-isotope protocol

Purpose of the reportThis study aimed at assessing an original low-dose dual-isotope procedure in which the abnormal stress Tc-99m Sestamibi SPECT is followed by rest Tl-201 SPECT, along with a head-to-head comparison with a single-isotope procedure. Methods and resultsOne hundred two patients, referred for a low-dose stress-SPECT with Sestamibi (123 ± 20 MBq) on a CZT camera and for whom a rest Sestamibi SPECT was warranted, had an additional Tl-201 rest-SPECT (52 ± 5 MBq) between stress and rest Sestamibi SPECT recordings. Tl-201 images were processed for spill-over and scatter corrections, and uptake differences with stress Sestamibi SPECT were analyzed: (1) for rest acquisitions from Tl-201 (dual-isotope procedure) and from Sestamibi (single-isotope procedure) and (2) in segments for which a diagnosis of ischemia, infarct, or normal perfusion was achieved. Mean effective dose was 8.3 mSv for dual-isotope but would decrease to 5.7 mSv for an expected rate of 37% of patients for whom rest-SPECT is not warranted. After a further background correction of Tl-201 images, the rest–stress difference in myocardial uptake was equivalent between dual- and single-procedures for identifying ischemic segments (respective areas-under-curves: 0.83 ± 0.03 and 0.81 ± 0.03). ConclusionThis original dual-isotope procedure provides acceptable radiation doses and consistent results, as compared with conventional single-isotope.