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BACKGROUND: Myocardial perfusion imaging (MPI) with single photon emission computed tomography is an established non-invasive technique for assessing myocardial ischemia. This method involves the intravenous administration of a radiopharmaceutical that accumulates in the heart muscle proportional to regional blood flow. However, image quality and diagnostic accuracy can be compromised by various technical and patient-related factors, including high non-specific radiopharmaceutical uptake in abdominal organs such as the stomach, intestines, liver, and gall-bladder, leading to subdiaphragmatic artifacts. These artifacts are particularly problematic for evaluating inferior wall perfusion and often necessitate repeated imaging, which decreases gamma camera availability and prolongs imaging times. CONCLUSIONS: Despite numerous investigated techniques to reduce interfering gastrointestinal activity, results have been inconsistent, and current MPI guidelines provide scant information on effective procedures to mitigate this issue. Based on our experience, some possible approaches to reducing artifacts include choosing stress testing with an exercise stress test, when possible, late imaging, fluid intake, and consuming carbonated water immediately before imaging.
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Artefactos , Imagen de Perfusión Miocárdica , Tomografía Computarizada de Emisión de Fotón Único , Humanos , Imagen de Perfusión Miocárdica/métodos , Tomografía Computarizada de Emisión de Fotón Único/métodos , Radiofármacos/administración & dosificación , Diafragma/diagnóstico por imagen , Prueba de Esfuerzo/métodos , Isquemia Miocárdica/diagnóstico por imagen , Isquemia Miocárdica/fisiopatologíaRESUMEN
Various techniques have been used in attempts to reduce interfering gastrointestinal activity in myocardial perfusion imaging (MPI); however, these approaches have yielded inconsistent results. The goal of this study was to investigate the efficacy of monitored walking, a previously unexplored technique, in reducing subdiaphragmatic activity-related artifacts during pharmacologic stress 99mTc-tetrofosmin MPI with SPECT to improve the overall image quality. Methods: The study included patients who underwent MPI with pharmacologic stress. They were given a step counter immediately after the radiotracer injection and were randomized into a group A, with a request to walk at least 1,000 steps before imaging, and a group B, with no specific instructions about walking. The reconstructed SPECT images were assessed visually. Moderate and severe levels of subdiaphragmatic tracer activity were considered relevant for the interpretation of the scans. Additionally, myocardial and abdominal activity was semiquantitatively assessed on raw planar images, and the mean myocardium-to-abdomen count ratios were calculated. Results: We enrolled 199 patients (95 patients in group A and 104 patients in group B). Clinical characteristics did not differ significantly between the 2 groups. Patients in group A walked more steps than patients in group B (P < 0.001), but there were no differences in the proportion of accepted scans between the 2 groups (P = 0.41). Additionally, there were no differences in the proportion of relevant subdiaphragmatic activity between the groups (P = 0.91). The number of steps did not impact the acceptance rate (P = 0.29). Conclusion: A higher number of steps walked during the waiting period between pharmacologic stress and acquisition does not affect subdiaphragmatic activity-related artifacts or the proportion of accepted scans after pharmacologic stress. However, pedometer use and clear instructions motivate patients to walk while awaiting imaging. Larger studies are required to compare a higher-step-count group with a sedentary control group to assess the influence of walking on gastrointestinal artifacts in MPI.
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BACKGROUND: The value of physiological ischemia versus anatomic severity of disease for prognosis and management of patients with stable coronary artery disease (CAD) is widely debated. METHODS: A total of 1764 patients who had rest-stress cadmium-zinc-telluride single-photon emission computed tomography myocardial perfusion imaging and angiography (invasive or computed tomography) were prospectively enrolled and followed for cardiac death/nonfatal myocardial infarction. The CAD prognostic index (CADPI) was used to quantify the extent and severity of angiographic disease. Prognostic value was assessed using Cox models, adjusted for pretest risk, known CAD, stressor, left ventricular ejection fraction, %ischemia and infarct, CADPI, and early (90-day) revascularization. Incremental prognostic value was evaluated using net reclassification index. RESULTS: The mean age was 69.7±9.5 years, 24.4% were women, and 29.3% had known CAD. Significant ischemia (>10%) was present in 28.4%. Nonobstructive, single, and multivessel disease was present in 256 (14.5%), 772 (43.8%), and 736 (41.7%), respectively. Early revascularization occurred in 579 (32.8%). Cardiac death/myocardial infarction occurred in 148 (8.4%) over a 4.6-year median follow-up. Both %ischemia and CADPI provided independent and incremental prognostic value over pretest clinical risk (P<0.001). In a model containing both ischemia and anatomy, ischemia was prognostic (hazard ratio per 5% ↑, 1.35 [95% CI, 1.11-1.63]; P=0.002) but CADPI was not (hazard ratio per 10-unit ↑, 1.09 [95% CI, 0.99-1.20]; P=0.07). Early revascularization modified the risk associated with %ischemia (interaction P=0.003) but not with CADPI (interaction P=0.6). %Ischemia and single-photon emission computed tomography variables added incremental prognostic value over clinical risk and CADPI (net reclassification index, 20.3% [95% CI, 9%-32%]; P<0.05); however, CADPI was not incrementally prognostic beyond pretest risk, %ischemia, and single-photon emission computed tomography variables (net reclassification index, 3.1% [95% CI, -5% to 15%]; P=0.21). CONCLUSIONS: Ischemic burden provides independent and incremental prognostic value beyond CAD anatomy and identifies patients who benefit from early revascularization. The anatomic extent of disease has independent prognostic value over clinical risk factors but offers limited incremental benefit for prognosis and guiding revascularization beyond physiological severity (ischemia).
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Angiografía Coronaria , Enfermedad de la Arteria Coronaria , Imagen de Perfusión Miocárdica , Revascularización Miocárdica , Humanos , Femenino , Masculino , Anciano , Revascularización Miocárdica/métodos , Imagen de Perfusión Miocárdica/métodos , Estudios Prospectivos , Persona de Mediana Edad , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/mortalidad , Enfermedad de la Arteria Coronaria/fisiopatología , Enfermedad de la Arteria Coronaria/terapia , Enfermedad de la Arteria Coronaria/diagnóstico , Enfermedad de la Arteria Coronaria/cirugía , Pronóstico , Valor Predictivo de las Pruebas , Isquemia Miocárdica/fisiopatología , Isquemia Miocárdica/diagnóstico , Isquemia Miocárdica/mortalidad , Factores de Riesgo , Índice de Severidad de la Enfermedad , Tomografía Computarizada de Emisión de Fotón Único , Medición de Riesgo , Vasos Coronarios/diagnóstico por imagen , Vasos Coronarios/fisiopatología , Angiografía por Tomografía Computarizada , Factores de TiempoAsunto(s)
Enfermedad de la Arteria Coronaria , Revascularización Miocárdica , Humanos , Enfermedad de la Arteria Coronaria/cirugía , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/diagnóstico , Enfermedad de la Arteria Coronaria/complicaciones , Enfermedad de la Arteria Coronaria/terapia , Pronóstico , Revascularización Miocárdica/métodos , Enfermedad Crónica , Isquemia Miocárdica/diagnóstico , Isquemia Miocárdica/terapia , Isquemia Miocárdica/cirugía , Valor Predictivo de las Pruebas , Angiografía CoronariaRESUMEN
BACKGROUND: Kidney transplantation provides substantial benefits in extending survival and improving quality of life for patients with end-stage renal disease. The incidence of major adverse cardiac events (MACE) increases with a decline of kidney function in patients with chronic kidney disease. After kidney transplantation, the incidence of MACE remains high. The objective of this study was to assess the prognostic significance of pre-transplant single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in kidney transplant recipients. METHODS: A systematic literature search was performed between January 1st 2015 and March 26th 2024 in PubMed, EMBASE, Web of Science and The Cochrane Library to identify the prognostic value of SPECT MPI for developing MACE (primary outcome) and mortality (secondary outcome) in kidney transplant recipients (PROSPERO CRD42020188610). Risk of bias was assessed. Meta-analyses and subgroup analyses were performed using random-effects models. RESULTS: Six studies comprising 2090 SPECT MPI scans were included. Abnormal SPECT MPI scans were associated with an increased risk of MACE post-transplantation (HR 1.62, 95% CI 1.27-2.06, p < 0.001). Subgroup analyses showed consistent findings across various patient populations and methodological differences. Sensitivity analyses supported the robustness of our findings. CONCLUSIONS: Current evidence showed that pre-transplant SPECT MPI has significant prognostic value in identifying kidney transplant candidates at risk for MACE post-transplantation. Integrating SPECT MPI into preoperative assessments might enhance risk stratification and guide clinical decision-making. Prospective studies are needed to refine risk prediction models.
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OBJECTIVE: Transient ischaemic dilatation (TID) had incremental diagnostic and prognostic value in obstructive coronary artery disease (CAD), but its clinical significance in patients with non-obstructive CAD remains unknown. We aimed to explore the prognostic value of TID in patients with non-obstructive CAD by 13N-ammonia PET imaging. METHODS: We retrospectively studied 131 consecutive patients with non-obstructive CAD undergoing one-day rest-stress 13N-ammonia PET myocardial perfusion imaging (MPI). TID was automatically generated using CardIQ Physio software. The receiver operative characteristic (ROC) curve was used to determine the optimal threshold of TID. The follow-up outcome was major adverse cardiac events (MACE), a composite of re-hospitalization for heart failure or unstable angina, late revascularization, non-fatal myocardial infarction, and cardiac death. Cardiac event-free survivals for normal and abnormal TID were compared using Kaplan-Meier plots and log-rank tests. RESULTS: During a median follow-up of 42.08 ± 17.67 months, 22 (16.7%) patients occurred MACE. The optimal cut-off value of TID was 1.03 based on MACE. Our preliminary outcome analysis suggests that TID-abnormal subjects had a lower overall survival probability. Furthermore, our multivariate analysis reveals abnormal TID was the only independent predictor for MACE in non-obstructive CAD. In the subgroup analysis, an abnormal TID was an independent predictor for MACE in patients with abnormal perfusion patterns. CONCLUSION: Among patients with non-obstructive CAD, PET-derived TID ≥ 1.03 may identify those with a high risk of subsequent MACE independently. It was also an independent risk factor for poor prognosis in patients with abnormal perfusion.
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BACKGROUND: Gated SPECT is an established technique for assessment of left ventricular function in cardiovascular disease patients. However, there is little information about the influence of diabetes mellitus on gated SPECT parameters. This study was established to assess gated SPECT parameters in Diabetes Mellitus (DM) and non-diabetes mellitus (non-DM) patients with normal Myocardial Perfusion Imaging (MPI). METHODS: In this analytical cross-sectional study, 314 patients (157 DM, 157 non-DM) with normal MPI were enrolled. Prevalence of risk factors for CAD like hypertension (HTN), and dyslipidemia were found to be significantly higher (p <0.01) in DM patients compared to non-DM. RESULTS: No statistically significant difference was observed among the TID, ESV, EDV, PFR, TTPF, and Wall Thickness (WT) parameters between DM and non-DM patients. Wall motion (Wm) in DM patients was significantly higher compared to non-DM patients. (3.9 ± 0.51 vs. 2.69 ± 0.48 for DM and non-DM patients, respectively, p-value:0.01). Also, there was no significant difference in Wm in the two groups with and without HTN. This shows the independent effect of DM on the Wm. CONCLUSION: This study believes that the Wm parameter should be noted for the early diagnosis or prevention of heart disease in DM patients. These findings can indicate the gradual changes in the movements of the left ventricle and the beginning of the progression of diabetic cardiomyopathy.
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PURPOSE: To assess myocardial injury using rest single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in patients with COVID-19 and to evaluate whether myocardial injury detected by rest MPI predict the prognosis of symptoms after 6 months follow-up. METHODS: Patients suspected of myocarditis between December 2022 and March 2023, after the lifting of COVID-19 pandemic restrictions, and between December 2018 and March 2019, prior to the pandemic, were referred to our study. All patients underwent rest MPI. One hundred and sixty four patients with COVID-19 infection after the lifting of pandemic restrictions and 101 patients before the pandemic were included as the study and control groups, respectively. One hundred and fifty three patients of the study group and 83 of the control group presented symptoms when they initially visit to our department. Compare the parameters of myocardial injury detected by rest SPECT MPI between the two groups and then investigate the association between myocardial injury and symptom prognosis in symptomatic patients of both groups. RESULTS: Total perfusion defect (TPD) (4.2% ± 3.3% vs. 2.3% ± 2.2%, P < 0.001), summed rest score (SRS) (5.3 ± 5.4 vs. 2.7 ± 2.0, P < 0.001), the proportion of patients with TPD > 4% (43.3% vs. 17.8%, P < 0.001), TPD > 10% (6.71% vs 0, P < 0.001), SRS > 4 (40.2% vs 15.8%, P < 0.001), SRS > 10 (12.8% vs 0, P < 0.001), the number of abnormal perfusion segments (3.9 ± 3.1 vs. 2.4 ± 1.7, P < 0.001) were all significantly higher in the study group. All the parameters of rest MPI were not associated with the prognosis of symptoms in symptomatic patients of both groups after 6 months follow-up. CONCLUSION: Myocardial injury in COVID-19 patients could be assessed by rest SPECT MPI. The COVID-19 patients could exhibited a higher frequency and greater severity of myocardial injury than uninfected control patients. Myocardial injury assessed by rest MPI did not predict for the prognosis of symptoms in symptomatic patients of both COVID-19 patients and uninfected patients.
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The combined supine-prone imaging protocol for SPECT myocardial perfusion imaging offers significant advantages over supine imaging alone. By comparing supine and prone images, one can distinguish attenuation artifacts in the inferior and anterior walls from true perfusion defects, thus improving specificity and diagnostic accuracy. The recommended protocol is to perform prone imaging after supine stress imaging when perfusion defects are noted. The additional prone imaging time is 20%-40% less than the standard supine imaging time. Implementing prone imaging can optimize patient care and provide substantial benefits for nuclear cardiology labs, especially those without attenuation correction.
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BACKGROUND: Myocardial perfusion SPECT (MPS) and exercise electrocardiography (Ex-ECG) results are of prognostic importance for short-term follow up duration. However, the value of MPS or Ex-ECG findings for long-term risk assessment is less evident as underlying risk factors for ischemic heart disease (IHD) gain in importance. OBJECTIVES: To assess the short- and long-term prognostic value of MPS and Ex-ECG in relation to known risk factors. METHODS AND MATERIALS: An observational study of 908 patients (age 63 years, 49% male, 45% prior IHD) referred for MPS and Ex-ECG. Follow-up was divided into two periods (short-term: <5 years and long-term: >5 years). Cardiac events were defined as a composite of acute myocardial infarction, unstable angina, unplanned revascularization and cardiovascular death. RESULTS: The composite endpoint occurred in 95 patients (short-term follow up) and in 94 patients (long-term follow up). In multivariable models stress testing had a strong predictive value for short-term follow up (HR for MPS = 2.9, CI = 1.9-4.5, p < 0.001 and HR for Ex-ECG = 2.1, CI 1.3-3.3, p = 0.002), but no predictive value for long-term follow up (HR for MPS = 0.9, CI = 0.5-1.5, p = 0.70 and HR for Ex-ECG = 1.0, CI = 0.6-1.6, p = 0.92). Male sex and prior IHD were significant predictors regardless of follow up duration. Age, diabetes and decreased exercise capacity were risk factors for long-term follow up. CONCLUSIONS: The prognostic value of MPS and Ex-ECG results are strong for short-term follow up but diminish over time and do not contribute significantly in multivariable models after 5 years. Long-term prognosis is primarily governed by underlying risk factors and exercise capacity.
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RATIONALE AND OBJECTIVES: To investigate the predictive value of coronary CT angiography (CCTA)-based radiomics for vessel-specific ischemia by stress dynamic CT myocardial perfusion imaging (MPI). MATERIALS AND METHODS: Patients with typical angina/atypical angina/non-angina chest pain who underwent both stress dynamic CT MPI and CCTA scans were retrospectively enrolled. The following models were constructed for ischemic prediction using logistic regression and CCTA-derived quantitative and radiomic features: plaque quantitative model, lumen quantitative model, CT-fractional flow reserve (CT-FFR) model, integrative quantitative model, plaque radiomic model, peri-coronary adipose tissue (pCAT) radiomic model, integrative radiomic model, and quantitative and radiomic fusion model. A relative myocardial blood flow ≤ 0.75 on stress dynamic CT MPI was considered ischemic. The models' performances were quantified by the area under the receiver-operating characteristic curve (AUC). RESULTS: 386 coronary vessels (stenosis grade: 25%â¼75%; training set: 200 [ischemia/non-ischemia=96/104]; test set:186 [ischemia/non-ischemia=79/107]) from 326 patients were included. The plaque radiomic model (training/test set: AUC=0.81/0.80) outperformed (p < .05) both the plaque quantitative (training/test set: AUC=0.71/0.68) model and the lumen quantitative (training/test set: AUC=0.69/0.65) model in identifying ischemia. The integrative radiomic model (training/test set: AUC=0.83/0.82) outperformed (p < .05) the CT-FFR model (training/test set: AUC=0.74/0.73) for ischemic prediction. The quantitative and radiomic fusion model (training/test set: AUC=0.86/0.84) outperformed (p < .05) the integrative quantitative model (training/test set: AUC=0.79/0.77) for ischemic detection. CONCLUSION: The plaque and pCAT radiomic features were superior to the plaque and pCAT quantitative features in predicting ischemia and the addition of the radiomic features to the quantitative features for ischemic identification yielded incremental discriminatory value.
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Many variables have been shown to impact accuracy and prognostic power of myocardial perfusion imaging (MPI); however, effects of left ventricular size have not been extensively studied. In particular, perfusion defects in smaller hearts could be overlooked due to partial volume averaging, potentially reducing the prognostic power of MPI. We determined stress total perfusion deficit (TPD) and rest end diastolic volume (REDV) from single photon emission computed tomography (SPECT) MPI in consecutive patients without pathologically dilated left ventricles. Area under the curve (AUC) and Cox regression analysis were used to assess prediction of subsequent major adverse cardiac events [MACE-death, hospitalized acute myocardial infarction (AMI), hospitalized unstable angina, late revascularization]. Analyses were stratified by sex and REDV tertile. The analytic population included 2,503 patients (965 men and 1,538 women). Outcomes were assessed over an average of 6.4±2.3 years. MACE was observed in 254 (26.3%) of 965 men and 261 (17.0%) of 1,538 women. Stress TPD showed significant AUCs for stratifying MACE risk regardless of sex and REDV tertile (all P<0.05). In Cox regression analysis, increasing stress TPD (but not REDV) was associated with MACE in both men and women. There was no significant TPD*REDV interaction. In conclusion, we found the prognostic power of SPECT MPI to be independent of left ventricular size.
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BACKGROUND: Stress myocardial perfusion single-photon emission computed tomography (SPECT) imaging (MPI) has been used to diagnose and predict the prognoses of patients with coronary artery disease (CAD). An ongoing multicenter collaboration established a Japanese database (J-ACCESS) in 2001 that includes a risk model and expert interpretations. The present study aimed to develop a novel algorithm using machine learning (ML) and resources from the J-ACCESS database to aid SPECT image interpretation. METHODS: We analyzed data from 1288 patients in J-ACCESS 3 and 4 databases. Three-dimensional (3D) stereoscopic images of left ventricular myocardial perfusion were reconstructed with linear transformation from the original short-axis data. Segments were extracted from U-Net, then features were extracted from each segment during the ML process. We estimated segmental scores based on weighted features obtained from fully connected layers. Correlations between segment scores interpreted by nuclear cardiology experts and estimated by ML were evaluated using a 17-segment model, summed stress (SSS), summed rest (SRS), and summed difference (SDS) scores, and ratios (%) of summed different scores (%SDS). RESULTS: The complete concordance rate of scores assessed by the experts and estimated by ML was 79.6%. The underestimated and overestimated rates were 10.3% and 10.0%, respectively. Associations between defect scores assessed by experts and ML were close, with correlation coefficients (r) of 0.923, 0.917, 0.842 and 0.853 for SSS, SRS, SDS, %SDS, respectively (p < 0.0001 for all). CONCLUSIONS: We created a new algorithm to estimate MPI scores using ML and the J-ACCESS database. This algorithm should provide accurate MPI interpretation even in facilities without specialist nuclear cardiologists, and might facilitate therapeutic decision-making and predict prognoses.
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BACKGROUND: We prospectively assessed the reproducibility of a novel low-dose single-volume dynamic computed tomography (CT) myocardial blood flow measurement technique. METHODS: Thirty-four pairs of measurements were made under rest and stress conditions in 13 swine (54.3 ± 12.3 kg). One or two acquisition pairs were acquired in each animal with a 10-min delay between each pair. Contrast (370 mgI/mL; 0.5 mL/kg) and a diluted contrast/saline chaser (0.5 mL/kg; 30:70 contrast/saline) were injected peripherally at 5 mL/s, followed by bolus tracking and acquisition of a single volume scan (100 kVp; 200 mA) with a 320-slice CT scanner. Bolus tracking and single volume scan data were used to derive perfusion in mL/min/g using a first-pass analysis model; the coronary perfusion territories of the left anterior descending (LAD), left circumflex (LCx), and right coronary artery (RCA) were automatically assigned using a previously validated minimum-cost path technique. The reproducibility of CT myocardial perfusion measurement within the LAD, LCx, RCA, and the whole myocardium was assessed via regression analysis. The average CT dose index (CTDI) of perfusion measurement was recorded. RESULTS: The repeated first (Pmyo1) and second (Pmyo2) single-volume CT perfusion measurements were related by Pmyo2 = 1.01Pmyo1 - 0.03(ρ = 0.96; RMSE = 0.08 mL/min/g; RMSE = 0.07 mL/min/g) for the whole myocardium, and by Preg2 = 0.86Preg1 + 0.13(ρ = 0.87; RMSE = 0.31 mL/min/g; RMSE = 0.29 mL/min/g) for the LAD, LCx, and RCA perfusion territories. The average CTDI of the single-volume CT perfusion measurement was 10.5 mGy. CONCLUSION: The single-volume CT blood flow measurement technique provides reproducible low-dose myocardial perfusion measurement using only bolus tracking data and a single whole-heart volume scan. RELEVANCE STATEMENT: The single-volume CT blood flow measurement technique is a noninvasive tool that reproducibly measures myocardial perfusion and provides coronary CT angiograms, allowing for simultaneous anatomic-physiologic assessment of myocardial ischemia. KEY POINTS: A low-dose single-volume dynamic CT myocardial blood flow measurement technique is reproducible. Motion misregistration artifacts are eliminated using a single-volume CT perfusion technique. This technique enables combined anatomic-physiologic assessment of coronary artery disease.
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Circulación Coronaria , Tomografía Computarizada por Rayos X , Animales , Porcinos , Reproducibilidad de los Resultados , Circulación Coronaria/fisiología , Tomografía Computarizada por Rayos X/métodos , Estudios Prospectivos , Imagen de Perfusión Miocárdica/métodos , Medios de Contraste/administración & dosificaciónRESUMEN
BACKGROUND: We aimed to develop a framework for generating three-dimensional (3D) myocardial blood flow (MBF) images, computing their accuracy against clinically validated two-dimensional (2D) polar MBF maps of the left ventricle, and evaluating their improvements in image quality over relative myocardial perfusion imaging (MPI). METHODS: N = 40 patients with a wide range of defect severities and uptake dynamics were retrospectively studied. The FlowQuant™ software was used to generate reference MPI and polar MBF maps and was adapted for voxel-wise MBF mapping. We evaluated agreement between parametric vs polar values for MBF at rest and stress and for reserve (stress/rest MBF). We also assessed improvements in image quality, assessed by signal-to-noise ratio, contrast-to-noise ratio, tissue-to-blood ratio, and defect severity, from relative MPI to MBF. RESULTS: There was excellent agreement between 3D parametric and 2D polar maps for all flow parameters (interclass correlation coefficient >0.96), albeit with minimal bias (<8%) for rest and stress MBF at the patient level. Image quality substantially improved from MPI to MBF in every patient for all image-quality metrics (P < 0.0001) CONCLUSIONS: We developed a robust methodology for producing highly accurate 3D MBF images exhibiting considerably improved image quality compared to relative MPI commonly used in clinical practice.
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BACKGROUND: The association between aortic valve stenosis (AVS) and myocardial perfusion abnormalities has been incompletely characterized. We sought to assess the predictors of myocardial ischemia in patients with mild-to-moderate AVS, and its relationship with long-term prognosis. METHODS: Eighty-nine patients with mild-to-moderate AVS (peak velocity between 2.6 and 4.0 m/second and aortic valve area > .6 cm2/m2), preserved left ventricular (LV) function, and either normal coronary arteries (28 patients) or non-obstructive coronary artery disease (<50% stenosis; 61 patients) were individuated. Myocardial perfusion imaging was performed using a cadmium-zinc-telluride camera, and the summed difference score (SDS) was computed. The presence of either LV hypertrophy (LVH) (LV mass index [LVMI] > 115 g/m2 [males] or 95 g/m2 [females]) or concentric LV remodeling (relative wall thickness: >.42) was determined at two-dimensional echocardiography. RESULTS: Forty (45%) and 49 (55%) patients had mild and moderate AVS, respectively. Fifty (56%), 17 (19%), and 22 (25%) patients had normal LV geometry, concentric LV remodeling, and LVH, respectively. An interaction between LV remodeling and inducible ischemia was revealed with progressively higher values of SDS in patients with normal LV geometry (3 ± 3), concentric remodeling (4 ± 2), and LVH (7 ± 2) (P < .001). Accordingly, a moderate correlation existed between LVMI and SDS values (R: .67; P < .001). After a median follow-up of 84 ± 47 months, 27 adverse events were recorded, including 19 AV replacements and 8 deaths. On multivariable analysis, the presence of LVH (hazard ratio [HR]: 6.46; 95% confidence interval [CI]: 2.09-20.00; P = .001) and a higher SDS (HR: 1.41; 95% CI: 1.15-1.75; P = .001) were the two independent predictors of AE. CONCLUSIONS: In patients with mild-to-moderate AVS, myocardial ischemia correlates with the severity of adverse LV remodeling. Patients with LVH and ischemia are at increased risk of AE.
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PURPOSE: The aim of this study was to evaluate the performance of myocardial perfusion imaging (MPI) systems in detecting perfusion defects (PDs). The defect perfusion index (DPI) was introduced to extend and further advance the current MPI quality metrics. METHODS: An anthropomorphic phantom simulating normal and pathological myocardial perfusion conditions was imaged by various NaI-crystal detector systems with and without corrections for scatter (SC) and attenuation (AC) (Symbia, Symbia + SC, Symbia IQ + SCAC, Symbia IQ), and cadmium-zinc-telluride detector systems without corrections (DSPECT, D530c). The extent of PD and the summed score (SS) were obtained by comparing polar maps with ad hoc normal databases created for each MPI system by using phantom polar maps with normal perfusion. The segmental uptake (SU) and the global uniformity (GU) were evaluated. The DPI was calculated on segments included in the PD to minimize attenuation artifacts outside the PD. The 17 segmental model was used. RESULTS: The highest level of uniformity of polar map was obtained for Symbia IQ + SCAC. D530c showed the highest extent of PD and dependence of the extent on the PD position. It showed in general the lowest SU values and the highest GU due to attenuation artifacts. Nevertheless, D530c outperforms other MPI systems in terms of PD detection, showing the highest DPI value. DSPECT system showed the lowest SS value, and DPI values comparable to NaI-crystal detector systems. CONCLUSION: The DPI can be evaluated to investigate the intrinsic ability of MPI systems to detect PDs, whatever the quantitative post-processing software used.
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Imagen de Perfusión Miocárdica , Fantasmas de Imagen , Imagen de Perfusión Miocárdica/instrumentación , Procesamiento de Imagen Asistido por Computador/métodos , Control de Calidad , HumanosRESUMEN
BACKGROUND: Adverse left ventricular remodeling is a significant cardiovascular predictor for patients with coronary artery disease and preserved left ventricular ejection fraction (LVEF). However, the remodeling indexes reflecting left ventricular spherization by myocardial perfusion imaging are underexplored. METHODS AND RESULTS: 727 patients (mean age 59.8±13.5 years, 329 women) diagnosed or suspected coronary artery disease with preserved LVEF who underwent resting myocardial perfusion imaging were retrospectively enrolled. The myocardial perfusion imaging findings including the total perfusion deficit and sphericity indexes (shape index (SI) and eccentricity index (EI) obtained from gated (QGS) and non-gated (QPS) images) were collected. Major adverse cardiovascular events (MACE) were followed up for 45.1±22.0 months. All patients were divided into 4 subgroups based on total perfusion deficit at 10% and LVEF at 65%. Univariable comparative analyses were performed in 5 cohorts (all patients and 4 subgroups). Patients who experienced MACE displayed higher SI and/or lower EI (all P<0.05). Kaplan-Meier survival analyses suggested significant differences for SIQPS in all 5 cohorts, for EIQPS and EIQGS in 4 cohorts, and for end-systolic and end-diastolic SIQGS in 3 cohorts (all P<0.05). Multivariate Cox analysis showed that abnormal SI and EI remained statistically significant predictors for MACE after adjusting for total perfusion deficit, LVEF, and other confounding factors. CONCLUSIONS: For patients diagnosed or suspected of coronary artery disease with preserved or supra-normal LVEF, resting sphericity indexes by myocardial perfusion imaging displayed incremental long-term prognostic value. Among these indicators, SIQPS is particularly promising across different perfusion or preserved functional conditions.
Asunto(s)
Enfermedad de la Arteria Coronaria , Imagen de Perfusión Miocárdica , Volumen Sistólico , Función Ventricular Izquierda , Humanos , Femenino , Masculino , Persona de Mediana Edad , Enfermedad de la Arteria Coronaria/fisiopatología , Enfermedad de la Arteria Coronaria/diagnóstico , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Volumen Sistólico/fisiología , Imagen de Perfusión Miocárdica/métodos , Estudios Retrospectivos , Pronóstico , Anciano , Función Ventricular Izquierda/fisiología , Remodelación Ventricular/fisiología , Valor Predictivo de las Pruebas , Ventrículos Cardíacos/fisiopatología , Ventrículos Cardíacos/diagnóstico por imagenRESUMEN
BACKGROUND: Several factors may decrease the accuracy of quantitative PET myocardial perfusion imaging (MPI). It is therefore essential to ensure that myocardial blood flow (MBF) values are reproducible and accurate, and to design systematic protocols to achieve this. Until now, no systematic phantom protocols have been available to assess the technical factors affecting measurement accuracy and reproducibility in MPI. MATERIALS AND METHODS: We implemented a standard measurement protocol, which applies a flow phantom in order to compare image-derived flow values with respect to a ground truth flow value with [15O]H2O MPI performed on both a Discovery MI (DMI-20, GE Healthcare) and a Biograph Vision 600 (Vision-600, Siemens Healthineers) system. Both systems have automatic [15O]H2O radio water generators (Hidex Oy) individually installed, allowing us to also study the differences occurring due to two different bolus delivery systems. To investigate the technical factors contributing to the modelled flow values, we extracted the [15O]H2O bolus profiles, the flow values from the kinetic modeling (Qin and Qout), and finally calculated their differences between test-retest measurements on both systems. RESULTS: The measurements performed on the DMI-20 system produced Qin and Qout values corresponging to each other as well as to the reference flow value across all test-retest measurements. The repeatability differences on DMI-20 were 2.1% ± 2.6% and 3.3% ± 4.1% for Qin and Qout, respectively. On Vision-600 they were 10% ± 8.4% and 11% ± 10% for Qin and Qout, respectively. The measurements performed on the Vision-600 system showed more variation between Qin and Qout values across test-retest measurements and exceeded 15% difference in 7/24 of the measurements. CONCLUSIONS: A preliminary protocol for measuring the accuracy and reproducibility of flow values in [15O]H2O MPI between digital PET/CT systems was assessed. The test-retest reproducibility falls below 15% in majority of the measurements conducted between two individual injector systems and two digital PET/CT systems. This study highlights the importance of implementing a standardized bolus injection and delivery protocol and importance of assessing technical factors affecting flow value reproducibility, which should be carefully investigated in a multi-center setting.