RESUMEN
BACKGROUND: The segment of the latest mechanical contraction (LMC) does not always overlap with the site of the latest electrical activation (LEA). By integrating both mechanical and electrical dyssynchrony, this proof-of-concept study aimed to propose a new method for recommending left ventricular (LV) lead placements, with the goal of enhancing response to cardiac resynchronization therapy (CRT). METHODS: The LMC segment was determined by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) phase analysis. The LEA site was detected by vectorcardiogram. The recommended segments for LV lead placement were as follows: (1) the LMC viable segments that overlapped with the LEA site; (2) the LMC viable segments adjacent to the LEA site; (3) If no segment met either of the above, the LV lateral wall was recommended. The response was defined as ≥15% reduction in left ventricular end-systolic volume (LVESV) 6-months after CRT. Patients with LV lead located in the recommended site were assigned to the recommended group, and those located in the non-recommended site were assigned to the non-recommended group. RESULTS: The cohort comprised of 76 patients, including 54 (71.1%) in the recommended group and 22 (28.9%) in the non-recommended group. Among the recommended group, 74.1% of the patients responded to CRT, while 36.4% in the non-recommended group were responders (P = .002). Compared to pacing at the non-recommended segments, pacing at the recommended segments showed an independent association with an increased response by univariate and multivariable analysis (odds ratio 5.00, 95% confidence interval 1.73-14.44, P = .003; odds ratio 7.33, 95% confidence interval 1.53-35.14, P = .013). Kaplan-Meier curves showed that pacing at the recommended LV lead position demonstrated a better long-term prognosis. CONCLUSION: Our findings indicate that pacing at the recommended segments, by integrating of mechanical and electrical dyssynchrony, is significantly associated with an improved CRT response and better long-term prognosis.
Asunto(s)
Terapia de Resincronización Cardíaca , Ventrículos Cardíacos , Vectorcardiografía , Humanos , Terapia de Resincronización Cardíaca/métodos , Femenino , Masculino , Anciano , Persona de Mediana Edad , Vectorcardiografía/métodos , Resultado del Tratamiento , Ventrículos Cardíacos/diagnóstico por imagen , Insuficiencia Cardíaca/diagnóstico por imagen , Insuficiencia Cardíaca/terapia , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Imagen de Perfusión Miocárdica/métodos , Prueba de Estudio Conceptual , Tomografía Computarizada de Emisión de Fotón Único , Dispositivos de Terapia de Resincronización CardíacaRESUMEN
In cardiac nuclear medicine examinations, absorption in the body is the main factor in the degradation of the image quality. The Chang and external source methods were used to correct for absorption in the body. However, fundamental studies on attenuation correction for electrocardiogram (ECG)-synchronized CT imaging have not been performed. Therefore, we developed and improved an ECG-synchronized cardiac dynamic phantom and investigated the synchronized time-phase-gated attenuation correction (STPGAC) method using ECG-synchronized SPECT and CT images of the same time phase. Methods: As a basic study, SPECT was performed using synchronized time-phase-gated (STPG) SPECT and non-phase-gated (NPG) SPECT. The attenuation-corrected images were, first, CT images with the same time phase as the ECG waveform of the gated SPECT acquisition (with CT images with the ECG waveform of the CT acquisition as the reference); second, CT images with asynchronous ECG; third, CT images of the 75% region; and fourth, CT images of the 40% region. Results: In the analysis of cardiac function in the phantom experiment, left ventricle ejection fraction (heart rate, 11.5%-13.4%; myocardial wall, 49.8%-55.7%) in the CT images was compared with that in the STPGAC method (heart rate, 11.5%-13.3%; myocardial wall, 49.6%-55.5%), which was closer in value to that of the STPGAC method. In the phantom polar map segment analyses, none of the images showed variability (F (10,10) < 0.5, P = 0.05). All images were correlated (r = 0.824-1.00). Conclusion: In this study, we investigated the STPGAC method using a SPECT/CT system. The STPGAC method showed similar values of cardiac function analysis to the CT images, suggesting that the STPGAC method accurately reconstructed the distribution of blood flow in the myocardial region. However, the target area for attenuation correction of the heart region was smaller than that of the whole body, and changing the gated SPECT conditions and attenuation-corrected images did not affect myocardial blood flow analysis.
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Electrocardiografía , Corazón , Procesamiento de Imagen Asistido por Computador , Fantasmas de Imagen , Corazón/diagnóstico por imagen , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Factores de Tiempo , Tomografía Computarizada de Emisión de Fotón Único/métodos , Tomografía Computarizada por Rayos X/métodos , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodosRESUMEN
Electrocardiogram (ECG)-gated single photon emission computed tomography myocardial perfusion imaging (GSPECT-MPI) is widely used for assessing coronary artery disease. Phase analysis on GSPECT-MPI can assess left ventricular mechanical dyssynchrony quantitatively on standard GSPECT-MPI alongside myocardial perfusion and function assessment. It has been shown that phase variables by GSPECT-MPI correlate well with tissue Doppler imaging by echocardiography. Main phase variables quantified by GSPECT-MPI are entropy, bandwidth, and phase standard deviation. Although those variables are automatically obtained from several software packages including Quantitative Gated SPECT and Emory Cardiac Toolbox, the methods for their measurement vary in each package. Several studies have shown that phase analysis has predictive value for response to cardiac resynchronization therapy and prognostic value for future adverse cardiac events beyond standard GSPECT-MPI variables. In this review, we summarize the basics of phase analysis on GSPECT-MPI and usefulness of phase analysis in clinical practice.
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Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca , Imagen de Perfusión Miocárdica , Disfunción Ventricular Izquierda , Humanos , Imagen de Perfusión Miocárdica/métodos , Tomografía Computarizada de Emisión de Fotón Único/métodos , Electrocardiografía , Corazón , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodosAsunto(s)
Terapia de Resincronización Cardíaca , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca , Imagen de Perfusión Miocárdica , Disfunción Ventricular Izquierda , Humanos , Tomografía Computarizada de Emisión de Fotón Único/métodos , Perfusión , Imagen de Perfusión Miocárdica/métodos , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodosRESUMEN
BACKGROUND: In patients with coronary artery disease (CAD), ischaemic cardiomyopathy may result in progressive cardiac remodelling and left ventricular (LV) dysfunction. Myocardial perfusion imaging (MPI) can be used to quantify LV size and shape, mechanical dyssynchrony (LVMD) and ejection fraction (EF) as well as myocardial ischaemia and injury extents. We investigated the prevalence of LV remodelling (LVR) in patients with CAD and the relationship between LVR, LVMD and EF. METHODS: Three hundred twenty-six patients with CAD were evaluated. The EF and end-diastolic volume (EDV) were measured using MPI. LVMD was assessed using phase analysis. LVR was characterised according to LV dilatation or increased shape indices (systolic shape index [SIES] and diastolic shape index [SIED]). RESULTS: LVR were observed in 41% of CAD patients. EDV, SIES and SIED were larger in patients with LVMD or low EF. After adjustment for age, sex and infarct and ischaemia extents, phase histogram bandwidth correlated with EDV (r = 0.218) and SIES (r = 0.266) and EF correlated with EDV (r = -0.535), SIES (r = -0.554) and SIED (r = -0.217, p < 0.001 for all). CONCLUSIONS: LVR is frequently seen in patients with CAD and may be detected even before the development of symptomatic heart failure. A large LV volume and a more spherical-shaped LV were associated with LVMD and low EF, highlighting the close relationships between remodelling and systolic dyssynchrony and dysfunction. MPI is useful for assessing LVR by providing information about LV size and shape, which changes from an ellipsoid towards a spherical form in the development of ischaemic cardiomyopathy.
Asunto(s)
Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca , Cardiomiopatías , Enfermedad de la Arteria Coronaria , Isquemia Miocárdica , Imagen de Perfusión Miocárdica , Disfunción Ventricular Izquierda , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Enfermedad de la Arteria Coronaria/complicaciones , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Humanos , Isquemia Miocárdica/complicaciones , Isquemia Miocárdica/diagnóstico por imagen , Imagen de Perfusión Miocárdica/métodos , Disfunción Ventricular Izquierda/diagnóstico por imagen , Disfunción Ventricular Izquierda/etiología , Remodelación VentricularAsunto(s)
Terapia de Resincronización Cardíaca , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca , Imagen de Perfusión Miocárdica , Terapia de Resincronización Cardíaca/métodos , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Cicatriz/diagnóstico por imagen , Humanos , Imagen de Perfusión Miocárdica/métodos , Perfusión , Tomografía Computarizada de Emisión de Fotón Único/métodosRESUMEN
BACKGROUND: SPECT myocardial perfusion imaging (MPI) provides an assessment of LV mechanical dyssynchrony (LVMD) which correlates with CVD outcomes in diverse populations including those awaiting renal transplant (RT). The current study examines the association of LVMD on pre-transplant MPI with long-term CVD mortality post RT. METHODS: We identified consecutive patients who underwent RT at the University of Alabama at Birmingham between 2008 and 2012 from our prospectively collected database. 675 patients in the database underwent MPI and had images amenable for phase analysis. A blinded investigator retrieved the studies and derived LVMD indices including histogram bandwidth (BW), standard deviation (SD), phase peak, phase skewness, and phase kurtosis. The primary outcome was CVD death after RT. RESULTS: The study cohort had a median age of 54 years, 56% were men, 43% had diabetes, and 7% had prior myocardial infarction. Patients were on dialysis for a median of 3.4 years prior to RT and 34% received living donor transplants. During a median follow-up time after RT of 4.7 years (IQR 3.5 to 6.3 years) 59 patients (9%) succumbed to CVD death. Patients with wider BW, wider SD, lower skewness, and lower kurtosis had an increased risk of CVD death. On multivariate adjustment, BW and skewness remained as independent predictors of CVD deaths. CONCLUSIONS: LVMD by phase analysis of gated SPECT MPI is associated with increased risk of CVD death after RT. This association is independent of demographics, comorbidities, and traditional findings on MPI and added incremental prognostic information. Assessment of LVMD should be considered for risk stratification in these patients.
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Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca , Trasplante de Riñón , Imagen de Perfusión Miocárdica , Disfunción Ventricular Izquierda , Masculino , Humanos , Persona de Mediana Edad , Femenino , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Tomografía Computarizada de Emisión de Fotón Único/métodos , Pronóstico , Imagen de Perfusión Miocárdica/métodosAsunto(s)
Terapia de Resincronización Cardíaca , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca , Imagen de Perfusión Miocárdica , Disfunción Ventricular Izquierda , Terapia de Resincronización Cardíaca/métodos , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Humanos , Imagen de Perfusión Miocárdica/métodos , Perfusión , Tomografía Computarizada de Emisión de Fotón Único/métodosRESUMEN
BACKGROUND: Left ventricular mechanical dyssynchrony (LVMD) induced by exercise stress was reported to be clinically useful in detecting multivessel coronary artery diseases. The aim of this study was to compare the prognostic value of LVMD induced by pharmacological stress with that induced by exercise stress. METHODS: We retrospectively examined 918 consecutive patients who underwent exercise (N = 310) or pharmacological stress (N = 608) 99mTc-tetrofosmin single-photon emission computed tomography (SPECT) with normal myocardial perfusion. LVMD was evaluated by phase analysis as the indices of phase bandwidth and phase standard deviation (PSD). RESULTS: During the follow-up period (2.2 ± 1.9 years), 74 major cardiac events (MCEs) occurred (7 cases of cardiac death, 17 cases of heart failure, and 50 cases of coronary intervention). In global patients, the indices of LVMD on rest images were significantly greater in patients with MCEs (bandwidth (°): 51 ± 31 vs 37 ± 21, P = .001, PSD: 14 ± 9 vs 10 ± 6, P = .001). The exercise stress bandwidth was significantly higher in patients with MCEs (62 ± 37° vs 42 ± 21°, P = .026), as was the pharmacological stress bandwidth (57 ± 35° vs 43 ± 24°, P = .006). Multivariate analysis demonstrated the exercise stress bandwidth to be an independent predictor of MCEs (HR 1.017, CI 1.003 to 1.032, P = .019), but the pharmacological stress bandwidth had no influence on MCEs. CONCLUSIONS: LVMD induced by exercise stress was an independent predictor of MCEs in patients with normal perfusion SPECT, whereas that induced by pharmacological stress had no association with further events.
Asunto(s)
Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca , Imagen de Perfusión Miocárdica , Disfunción Ventricular Izquierda , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Humanos , Imagen de Perfusión Miocárdica/métodos , Perfusión , Pronóstico , Estudios Retrospectivos , Tomografía Computarizada de Emisión de Fotón Único , Disfunción Ventricular Izquierda/diagnóstico por imagenRESUMEN
BACKGROUND: Planar equilibrium radionuclide angiocardiography (ERNA) has been used as the gold standard for assessment of left ventricular (LV) function for over three decades. However, this imaging modality has recently gained less favor due to growing concerns about radiation exposure. We developed a novel approach that involves integrating short axis slices of gated bloodpool SPECT for quantification of LV function with improved signal-to-noise ratio and reduced radioactive dose while maintaining image quality and quantitative precision. METHODS: Twenty patients referred for ERNA underwent standard in vitro 99mTc-labeling of red blood cells (RBC), and were initially imaged following a low-dose (~ 8 mCi) injection using a dedicated cardiac SPECT camera, and then had planar imaging following a high-dose (~ 25 mCi) injection. Four different quantification methods were utilized to assess the LV function and were compared for quantitative precision and inter-observer reproducibility of the quantitative assessments. RESULTS: The Yale method resulted in the most consistent assessment of LV function compared with the gold standard high-dose ERNA method, along with excellent inter-observer reproducibility. CONCLUSIONS: The new low-dose 99mTc-RBC imaging method provides precise quantification of LV function with a greater than 67% reduction in dose and may potentially improve assessment of regional function.
Asunto(s)
Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Imagen de Acumulación Sanguínea de Compuerta/métodos , Radiofármacos , Pertecnetato de Sodio Tc 99m , Disfunción Ventricular Izquierda/diagnóstico por imagen , Anciano , Angiografía Coronaria , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Volumen Sistólico , Disfunción Ventricular Izquierda/fisiopatologíaRESUMEN
OBJETIVO: Análisis de la relación coste-efectividad (RCE) del electrocardiograma de esfuerzo y de la SPECT de perfusión miocárdica esfuerzo-reposo en relación con la revascularización coronaria (RC), eventos cardíacos (EC) y mortalidad total (MT). MATERIAL Y MÉTODOS: Se estudiaron 8.496 pacientes con SPECT y seguimiento medio de 5,3±3,5años. Evaluamos la RCE para la RC quirúrgica (RCQ) y percutánea (RCP) (45,6%/54,4%) de acuerdo con los resultados de la isquemia electrocardiográfica y gammagráfica. La efectividad se evaluó como MT, EC, LYSO (life-year-saved-observed) y EC-LYSO. Los análisis de costes se realizaron desde la perspectiva del pagador de atención médica. El análisis de sensibilidad fue considerando las relaciones RCQ/RCP actuales (12%/88%). RESULTADOS: Al combinar los resultados del electrocardiograma de esfuerzo y de la gammagrafía, los valores de coste-efectividad para la RCQ variaron entre 112.589 (isquemia electrocardiográfica y gammagráfica) y 2.814.715 (sin isquemia)/evento evitado, y entre 38.664 y 2.221.559/LYSO; y para la RCP entre 18.824 (isquemia electrocardiográfica y gammagráfica) y 46.377 (sin isquemia)/evento evitado, y entre 6.464 y 36.604/LYSO. Para el EC: los valores de coste-efectividad de la RCQ y RCP en presencia de isquemia electrocardiográfica y gammagráfica fueron de 269.904/EC evitado y de 24.428/EC evitado, respectivamente; y los /LYSO de la RCQ y RCP fueron de 152.488 y 13.801, respectivamente. Se mantuvo la misma RCE para la proporción actual de pacientes revascularizados (12%/88%). CONCLUSIONES: El análisis combinado de las imágenes de la SPECT y del electrocardiograma de esfuerzo permite la diferenciación entre grupos de pacientes en donde la RCP y la RCQ son más rentables. La mayor RCE en relación con la RC, EC y MT se da en los pacientes con isquemia electrocardiográfica y gammagráfica. La RCP es más coste-efectiva que la RCQ
OBJECTIVE: The aim was to analyze the cost-effectiveness ratio (CER) of stress electrocardiogram (ES) and stress myocardial perfusion imaging (SPECT-MPI) according to coronary revascularization (CR) therapy, cardiac events (CE) and total mortality (TM). MATERIAL AND METHODS: A total of 8,496 consecutive patients who underwent SPECT-MPI were followed-up (mean 5.3±3.5years). Cost-effectiveness for coronary bypass (CABG) or percutaneous CR (PCR) (45.6%/54.4%) according to combined electrocardiographic ischemia and scintigraphic ischemia were evaluated. Effectiveness was evaluated as TM, CE, life-year saved observed (LYSO) and CE-LYSO; costs analyses were conducted from the perspective of the health care payer. A sensitivity analysis was performed considering current CABG/PCR ratios (12%/88%). RESULTS: When electrocardiogram and SPECT approaches are combined, the cost-effectiveness values for CABG ranged between 112,589 (electrocardiographic and scintigraphic ischemia) and 2,814,715 (without ischemia)/event avoided, 38,664 and 2,221,559/LYSO; for PCR ranged between 18,824 (electrocardiographic and scintigraphic ischemia) and 46,377 (without ischemia)/event avoided, 6,464 and 36,604/LYSO. To CE: the cost-effectiveness values of the CABG and CPR in presence of electrocardiographic and scintigraphic ischemia were 269,904/CE-avoided and 24,428/CE-avoided, respectively; and the /LYSO of the CABG and PCR were 152,488 and 13,801, respectively. The RCE was maintained for the current proportion of revascularized patients (12%/88%). CONCLUSIONS: Combined ES and SPECT-MPI results, allows differentiation between patient groups, where the PCR and CABG are more cost-effective in different economic frameworks. The major CER in relation to CR, CE and TM occurs in patients with electrocardiographic and scintigraphic ischemia. PCR is more cost-effective than CABG
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Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Prueba de Esfuerzo/métodos , Revascularización Miocárdica/métodos , Análisis Costo-Beneficio , Registros de Enfermedades/estadística & datos numéricos , Indicadores de Morbimortalidad , Electrocardiografía/métodos , Sensibilidad y EspecificidadRESUMEN
Technetium-labeled cardiac scintigraphy (i.e., Tc-PYP scan) has been repurposed for the diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM). Validated in cohorts of patients with heart failure and echocardiographic and/or cardiac magnetic resonance imaging findings suggestive of cardiac amyloidosis, cardiac scintigraphy can confirm the diagnosis of ATTR-CM only when combined with blood and urine testing to exclude a monoclonal protein. Multisocietal guidelines support the nonbiopsy diagnosis of ATTR-CM using cardiac scintigraphy, yet emphasize its use in the appropriate clinical context and the crucial need to rule out light chain amyloid cardiomyopathy. Although increased awareness of ATTR-CM and the advent of effective therapy have led to rapid adoption of diagnostic scintigraphy, there is heterogeneity in adherence to consensus guidelines. This perspective outlines clinical scenarios wherein findings on technetium-labeled cardiac scintigraphy have been misinterpreted, reviews causes of false-negative and false-positive results, and provides strategies to avoid costly and potentially fatal misdiagnoses.
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Amiloidosis/metabolismo , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Cardiomiopatías/metabolismo , Insuficiencia Cardíaca/metabolismo , Tecnecio , Amiloidosis/diagnóstico por imagen , Cardiomiopatías/diagnóstico por imagen , Insuficiencia Cardíaca/diagnóstico por imagen , Humanos , Imagen por Resonancia Cinemagnética/métodos , Compuestos de Organotecnecio/metabolismo , Trazadores Radiactivos , Cintigrafía/métodos , Tecnecio/metabolismoRESUMEN
BACKGROUND: Left ventricular contraction dyssynchrony (LVCD) has been related to induced ischemia and transmural scar but the interplay of myocardial viability and dyssynchrony is unknown. The aim of the present study was to establish the role of dyssynchrony in the context of a viability study performed with nitrate augmentation gated single photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI). METHODS: Fifty-four consecutive patients with ischemic dilated cardiomyopathy (IDC) and depressed left ventricular ejection fraction (LVEF) were included. They underwent a two-day rest/nitroglycerine (NTG) study GSPECT MPI to determine the myocardial viability. Patients with a nitrate-induced uptake increase of > 10% vs baseline, in at least, two consecutive dysfunctional segments were considered viable as well as those who showed no improvement in the uptake but the uptake was > 50% on post NTG study. Patients with no nitrate-induced uptake increase of > 10% and the uptake of < 50% were considered non-viable. Perfusion, function and LVCD were compared in 25 viable patients vs 29 non-viable patients at baseline and after NTG administration. RESULTS: After NTG administration, in the viable group, the LVEF increased (36.44 ± 6.64% vs 39.84 ± 6.39%) and the end-systolic volume decreased significantly (119.28 ± 31.77 mL vs 109.08 ± 33.17 mL) (P < 0.01). These patients also experienced a significant reduction in the LVCD variables: phase standard deviation was reduced in the post NTG study (57.77° ± 19.47° vs 52.02° ± 17.09°) as well as the phase histogram bandwidth (190.20° ± 78.83° vs 178.0° ± 76.14°) (P < 0.05). Functional and LVCD variables remained similar in the non-viable patients (P > 0.05). CONCLUSION: In patients with IDC and depressed LVEF, the myocardial viability detected by rest/ NTG GSPECT MPI, might determine LVCD improvement.
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Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Cardiomiopatía Dilatada/fisiopatología , Contracción Miocárdica/fisiología , Isquemia Miocárdica/fisiopatología , Imagen de Perfusión Miocárdica/métodos , Función Ventricular Izquierda/fisiología , Anciano , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: The aim of the study was to assess the agreement between the left ventricular ejection fraction (LVEF) values obtained with IQ-SPECT and those obtained with a conventional gamma camera equipped with low-energy high-resolution (LEHR), considered as the method of reference. METHODS: Gated-stress MPI using 99mTc-tetrofosmin was performed in 55 consecutive patients. The patients underwent two sequential acquisitions (Method A and B) performed on Symbia-IQ SPECT with different acquisition times and one (Method C) on a Ecam SPECT equipped with LEHR collimators. The values of the different datasets were compared using the Bland-Altman analysis method: the bias and the limits of agreement (LA) were estimated in a head-to-head comparison of the three protocols. RESULTS: In the (Method A-Method C) comparison for LVEF, the bias was 3.8% and the LAs ranged from - 9.3% to 16.8%. The agreement was still lower between Method B and C, whilst only slightly improved when Methods A and B were compared. CONCLUSIONS: The wide amplitude in LA intervals of about 30% indicates that IQ and LEHR GSPECT are not interchangeable. The values obtained with IQ-SPECT should only be used with caution when evaluating the functional state of the heart.
Asunto(s)
Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Enfermedad de la Arteria Coronaria/fisiopatología , Procesamiento de Imagen Asistido por Computador/métodos , Volumen Sistólico/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Algoritmos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Imagen de Perfusión Miocárdica , Compuestos Organofosforados , Compuestos de Organotecnecio , Radiofármacos , Reproducibilidad de los Resultados , Programas InformáticosRESUMEN
BACKGROUND: We previously optimized several reconstruction strategies in SPECT myocardial perfusion imaging (MPI) with low dose for perfusion-defect detection. Here we investigate whether reducing the administered activity can also maintain the diagnostic accuracy in evaluating cardiac function. METHODS: We quantified the myocardial motion in cardiac-gated stress 99m-Tc-sestamibi SPECT studies from 163 subjects acquired with full dose (29.8 ± 3.6 mCi), and evaluated the agreement of the obtained motion/thickening and ejection fraction (EF) measures at various reduced dose levels (uniform reduction or personalized dose) with that at full dose. We also quantified the detectability of abnormal motion via a receiver-operating characteristics (ROC) study. For reconstruction we considered both filtered backprojection (FBP) without correction for degradations, and iterative ordered-subsets expectation-maximization (OS-EM) with resolution, attenuation and scatter corrections. RESULTS: With dose level lowered to 25% of full dose, the obtained results on motion/thickening, EF and abnormal motion detection were statistically comparable to full dose in both reconstruction strategies, with Pearson's r > 0.9 for global motion measures between low dose and full dose. CONCLUSIONS: The administered activity could be reduced to 25% of full dose without degrading the function assessment performance. Low dose reconstruction optimized for perfusion-defect detection can be reasonable for function assessment in gated SPECT.
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Corazón/diagnóstico por imagen , Imagen de Perfusión Miocárdica/métodos , Tecnecio Tc 99m Sestamibi , Tomografía Computarizada de Emisión de Fotón Único/métodos , Anciano , Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Femenino , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Movimiento (Física) , Perfusión , Curva ROC , Reproducibilidad de los Resultados , Dispersión de Radiación , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: Phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy provides a measure of left ventricular dyssynchrony and may have applications for identifying patients suitable for cardiac resynchronisation therapy. Phase analysis is typically described in degrees of cardiac cycle, less intuitive to cardiologists familiar with ECGs. We assessed the relationship between time and degrees, to determine whether they are interchangeable. METHODS AND RESULTS: 399 patients underwent normal stress-only SPECT myocardial perfusion imaging using Technetium-99m-tetrofosmin. Data analysis used QGS software (Cedars Sinai) calculating bandwidth and standard deviation. Heart rate, age, gender, stress modality, and ejection fraction were analyzed for their relation to phase variables. 13 patients were excluded for conduction abnormalities including right and left bundle branch block and ventricular pacing. Heart rate was strongly correlated to bandwidth and standard deviation measured in time, but unrelated when measured in degrees. Although bandwidth measured by time and degrees were strongly correlated with each other this relationship was not perfect (correlation coefficient 0.87, P < .001). The addition of heart rate to the model explained most of the residual variation between the two. The results for standard deviation were similar. CONCLUSION: In patients with normal myocardial perfusion and QRS duration bandwidth measured by degrees is not directly interchangeable with time in milliseconds. However most of the variation is explainable by heart rate, which predominantly affects measures of time rather than degrees. We would propose that although the values are less intuitive to cardiologists, normal ranges for phase measured in degrees are potentially more robust.
Asunto(s)
Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Frecuencia Cardíaca , Ventrículos Cardíacos/diagnóstico por imagen , Imagen de Perfusión Miocárdica/métodos , Tomografía Computarizada de Emisión de Fotón Único/métodos , Disfunción Ventricular Izquierda/diagnóstico por imagen , Anciano , Toma de Decisiones , Electrocardiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Compuestos Organofosforados/química , Compuestos de Organotecnecio/química , Reproducibilidad de los Resultados , Estudios Retrospectivos , Programas Informáticos , Estrés Fisiológico , Interfaz Usuario-ComputadorRESUMEN
BACKGROUND: Quantitative cardiac contractile function assessment is the primary indicator of disease progression and therapeutic efficacy in small animals. Operator dependency is a major challenge with commonly used echocardiography. Simultaneous assessment of cardiac perfusion and function in nuclear scans would reduce burden on the animal and facilitate longitudinal studies. We evaluated the accuracy of contractile function measurements obtained from electrocardiogram-gated nuclear perfusion imaging compared with anatomic imaging. METHODS AND RESULTS: In healthy C57Bl/6N mice (n = 11), 99mTc-sestamibi SPECT and 13N-ammonia PET underestimated left ventricular volumes (23 to 28%, P = 0.02) compared to matched anatomic images, though ejection fraction (LVEF) was comparable (%, SPECT: 73 ± 8 vs CMR: 72 ± 6, P = 0.1). At 1 week after myocardial infarction (n = 13), LV volumes were significantly lower in perfusion images compared to CMR and contrast CT (P = 0.003), and LVEF was modestly overestimated (%, SPECT: 37 ± 8, vs CMR: 27 ± 7, P = 0.003). Nuclear images exhibited good intra- and inter-reader agreement. Perfusion SPECT accurately calculated infarct size compared to histology (r = 0.95, P < 0.001). CONCLUSIONS: Cardiac function can be calculated by gated nuclear perfusion imaging in healthy mice. After infarction, perfusion imaging overestimates LVEF, which should be considered for comparison to other modalities. Combined functional and infarct size analysis may optimize imaging protocols and reduce anaesthesia duration for longitudinal studies.
Asunto(s)
Tomografía Computarizada por Emisión de Fotón Único Sincronizada Cardíaca/métodos , Contracción Miocárdica/fisiología , Infarto del Miocardio/diagnóstico por imagen , Imagen de Perfusión Miocárdica/métodos , Animales , Masculino , Ratones , Ratones Endogámicos C57BL , Infarto del Miocardio/fisiopatología , Tecnecio Tc 99m Sestamibi , Función Ventricular IzquierdaRESUMEN
AIM: The aim of this study is to develop and validate a new method to diagnose apical hypertrophic cardiomyopathy (AHCM) by the integral quantitative analysis of myocardial perfusion and wall thickening from gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). PATIENTS AND METHODS: Twenty-two consecutive patients, who showed T wave inversion of at least 3 mm in precordial leads and sinus rhythm in ECG, were enrolled. All the patients underwent cardiac magnetic resonance (CMR), gated rest SPECT MPI and echocardiography. According to CMR diagnostic results, 13 patients were categorized as in the AHCM group and the remaining nine patients were categorized as in the non-AHCM group. Operators who were blinded to the CMR diagnosis independently performed the diagnosis by gated SPECT MPI. The regions of interest inside the apical hotspots on the perfusion polar map were drawn and the mean values of wall thickening in the drawn region of interests were calculated. Using MRI diagnosis as the gold standard, AHCM was diagnosed based on receiver operating characteristic analysis of the mean wall thickening in the apical perfusion hotspot. The area under curve, sensitivity, specificity, and accuracy of our method were 0.97, 100%, 89%, and 95%, respectively. CONCLUSION: Our new method has high sensitivity, specificity, and accuracy against CMR diagnosis. It has great promise to become a clinical tool in the diagnosis of AHCM.