Beam hardening artifact reduction using dual energy computed tomography: implications for myocardial perfusion studies

Background: Myocardial perfusion computed tomography (CTP) using conventional single energy (SE) imaging is influenced by the presence of beam hardening artifacts (BHA), occasionally resembling perfusion defects and commonly observed at the left ventricular posterobasal wall (PB). We therefore sought to explore the ability of dual energy (DE) CTP to attenuate the presence of BHA. Methods: Consecutive patients without history of coronary artery disease who were referred for computed tomography coronary angiography due to atypical chest pain and a normal stress-rest SPECT and had absence or mild coronary atherosclerosis constituted the study population. The study group was acquired using DE and the control group using SE imaging. Results: Demographical characteristics were similar between groups, as well as the heart rate and the effective radiation dose. Myocardial signal density (SD) levels were evaluated in 280 basal segments among the DE group (140 PB segments for each energy level from 40 keV to 100 keV; and 140 reference segments), and in 40 basal segments (at the same locations) among the SE group. Among the DE group, myocardial SD levels and myocardial SD ratio evaluated at the reference segment were higher at low energy levels, with significantly lower SD levels at increasing energy levels. Myocardial signal-to-noise ratio was not significantly influenced by the energy level applied, although 70 keV was identified as the energy level with the best overall signal-to-noise ratio. Significant differences were identified between the PB segment and the reference segment among the lower energy levels, whereas at ≥ 70 keV myocardial SD levels were similar. Compared to DE reconstructions at the best energy level (70 keV), SE acquisitions showed no significant differences overall regarding myocardial SD levels among the reference segments. Conclusions: Beam hardening artifacts that influence the assessment of myocardial perfusion can be attenuated using DE at 70 keV or higher.Fil: Rodriguez Granillo, Gaston Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; Argentina. Diagnóstico Maipú; ArgentinaFil: Carrascosa, Patricia. Diagnóstico Maipú; ArgentinaFil: Cipriano, Silvia. Diagnóstico Maipú; ArgentinaFil: De Zan, Macarena. Diagnóstico Maipú; ArgentinaFil: Deviggiano, Alejandro. Diagnóstico Maipú; ArgentinaFil: Capunay, Carlos. Diagnóstico Maipú; ArgentinaFil: Cury, Ricardo C.. Miami Cardiac and Vascular Institute and Baptist Health; Estados Unido

Myocardial signal density levels and beam-hardening artifact attenuation using dual-energy computed tomography

The assessment of myocardial perfusion using single-energy (SE) imaging is influenced by beam-hardening artifacts (BHA). We sought to explore the ability of dual-energy (DE) imaging to attenuate the presence of BHA. Myocardial signal density (SD) was evaluated in 2240 myocardial segments (112 for each energy level) and in 320 American Heart Association segments among the SE group. Compared to DE reconstructions at the best energy level, SE acquisitions showed no significant differences overall regarding myocardial SD or signal-to-noise ratio. The segments most commonly affected by BHA showed significantly lower myocardial SD at the lowest energy levels, progressively normalizing at higher energy levels.Fil: Rodriguez Granillo, Gaston Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; Argentina. Diagnóstico Maipú; ArgentinaFil: Carrascosa, Patricia. Diagnóstico Maipú; ArgentinaFil: Cipriano, Silvina. Diagnóstico Maipú; ArgentinaFil: de Zan, Macarena. Diagnóstico Maipú; ArgentinaFil: Deviggiano, Alejandro. Diagnóstico Maipú; ArgentinaFil: Capunay, Carlos. Diagnóstico Maipú; ArgentinaFil: Cury, Ricardo C.. Miami Cardiac and Vascular Institute; Estados Unidos. Baptist Health of South Florida; Estados Unido

Dual energy imaging and intracycle motion correction for CT coronary angiography in patients with intermediate to high likelihood of coronary artery disease

We explored whether intracycle motion correction algorithms (MCAs) might be applicable to dual energy computed tomography coronary angiography in patients with intermediate to high likelihood of coronary artery disease. MCA reconstructions were associated with higher interpretability rates (96.7% vs 87.9%, P < .001), image quality scores (4.12±0.9 vs. 3.76±1.0; P < .0001), and diagnostic performance [area under the curve of 0.95 (95% confidence interval [CI] 0.92-0.97) vs 0.89 (95% CI 0.86-0.92); P < .0001] compared to conventional reconstructions. In conclusion, application of intracycle MCA reconstructions to dual energy computed tomography acquisitions was feasible and resulted in significantly higher image quality scores, interpretability, and diagnostic performance.Fil: Carrascosa, Patricia. Diagnóstico Maipú; ArgentinaFil: Deviggiano, Alejandro. Diagnóstico Maipú; ArgentinaFil: Leipsic, Jonathon A.. St. Paul's Hospital; CanadáFil: Capunay, Carlos. Diagnóstico Maipú; ArgentinaFil: De Zan, Macarena C.. Diagnóstico Maipú; ArgentinaFil: Goldsmit, Alejandro. Sanatorio Güemes; ArgentinaFil: Rodriguez Granillo, Gaston Alfredo. Diagnóstico Maipú; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; Argentin

Pericardial and visceral, but not total body fat, are related to global coronary and extra-coronary atherosclerotic plaque burden

Background: To explore the relationship between coronary and extra-coronary atherosclerotic plaque burden with total and regional fat depots among patients undergoing ECG-gated aortic computed tomography angiography (CTA). Methods: The subjects of this study comprised a cohort of consecutive patients who underwent ECG-gated thoracoabdominal CTA. We assessed the number of coronary segments with plaques (segment-involvement score, SIS); and the extra-coronary atherosclerotic plaque burden, comprising the aorta and supra-aortic trunks, iliofemoral arteries, and visceral arteries (extra-coronary SS). Total and regional fat volume (FV) were calculated. Results: A total of 2700 vascular segments were evaluated in 90 patients. Obese patients (n = 31, 34%) showed similar coronary SIS (p = 0.41) and extra-coronary SS (p = 0.22) than non-obese patients. General body fat measurements were not related to atherosclerotic plaque burden scores, without associations between coronary or extra-coronary plaque burden and BMI (p = 0.68, and p = 0.91), abdominal circumference (p = 0.13, p = 0.89), total body FV (p = 0.50, p = 0.98), or abdominal FV (p = 0.51, p = 0.99). Pericardial FV was related to coronary SIS (p < 0.0001) and extra-coronary SS (p = 0.008), and visceral FV was related to the coronary SIS (p = 0.006) and extra-coronary SS (p = 0.056). Abdominal subcutaneous fat was inversely related to coronary SIS (p = 0.038) and extra-coronary SS (p = 0.010). Pericardial FV was identified as the only independent predictor of extensive coronary [OR 1.020 (95% CI 1.001–1.039), p = 0.036] and extra-coronary [OR 1.018 (95% CI 1.001–1.036), p = 0.035] plaque burden. Conclusions: In the present study, pericardial and visceral fat were associated with an increased atherosclerotic burden, whereas we identified an inverse relationship between subcutaneous abdominal fat and plaque burden.Fil: Rodriguez Granillo, Gaston Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Diagnóstico Maipú; ArgentinaFil: Reynoso, Exequiel. Diagnóstico Maipú; ArgentinaFil: Capunay, Carlos. Diagnóstico Maipú; ArgentinaFil: Carpio, Jimena. Diagnóstico Maipú; ArgentinaFil: Carrascosa, Patricia. Diagnóstico Maipú; Argentin

Atherosclerotic plaque burden evaluated from neck to groin: Effect of gender and cardiovascular risk factors

We explored the impact of gender and cardiovascular risk factors (RF) in the distribution and burden of coronary and extra-coronary atherosclerotic plaques among patients undergoing ECG-gated thoracoabdominal computed tomography angiography (CTA) from the supra-aortic trunks to the femoral arteries. We included a consecutive cohort of patients who underwent ECG-gated thoracoabdominal aortic CTA from the supra-aortic trunks to the pubic symphysis. We evaluated the number of coronary segments with plaques [segment-involvement score (SIS)]; and the extra-coronary atherosclerotic plaque burden, comprising the aorta and supra-aortic trunks, iliofemoral arteries, and visceral arteries (extra-coronary SS). A total of 3400 vascular segments were evaluated in 100 patients (mean age 67.0 ± 12.6 years, 66% male). Seventy-two (72%) patients had evidence of atherosclerosis in the coronary tree (coronary SIS ≥ 1), of which 32% was extensive (coronary SIS > 5). Males had a significantly higher prevalence of coronary SIS ≥ 1 [53 (80%), vs. 19 (56%), p = 0.018], and coronary SIS > 5 [24 (36%) vs. 8 (24%), p = 0.035] than females. Extra-coronary SS was similar between genders (males 10.2 ± 5.8 vs. females 9.7 ± 5.4, p = 0.70), irrespective of the location along the different vascular beds. The number of coronary RF was significantly related to the coronary SIS (p = 0.038), and hypertension and diabetes were consistently related to coronary and extra-coronary plaque burden. In the present study involving analysis of multiple vascular beds from the supra-aortic trunks to the femoral arteries, we identified significant sex-related differences in coronary plaque burden, whereas extra-coronary plaque burden was similar between genders irrespective of the vascular bed assessed.Fil: Rodriguez Granillo, Gaston Alfredo. Diagnóstico Maipú; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; ArgentinaFil: Campisi, Roxana. Diagnóstico Maipú; ArgentinaFil: Reynoso, Exequiel. Diagnóstico Maipú; ArgentinaFil: Capunay, Carlos. Diagnóstico Maipú; ArgentinaFil: Carrascosa, Patricia. Diagnóstico Maipú; Argentin

Predictive Value of Global Plaque Burden Nomograms Estimated by Conventional Computed Tomography Scan

Introducción: La calcificación coronaria, de valor pronóstico establecido, puede valorarse por tomografía computarizada (TC) de tórax convencional. Objetivo: Explorar el valor pronóstico de los nomogramas de carga global de placa ateroesclerótica aplicados a datos obtenidos de la (TC) de tórax convencional. Material y métodos: Incluimos pacientes consecutivos de 40 a 74 años que se sometieron a una (TC) de tórax en nuestra institución entre agosto y diciembre de 2012 por diversas indicaciones. Se evaluó la presencia y extensión de calcificaciones coronarias y los pacientes fueron clasificados según el percentil de la puntuación de afectación de segmento por edad y sexo (CACSIS). Resultados: Se incluyeron 1194 pacientes. Tras un seguimiento medio de 3,7 ± 0,5 años, 53 (4,4%) pacientes fallecieron. Se identificó una relación significativa entre las tasas de sobrevida ajustadas según sexo y edad y el percentil de la puntuación de afectación de segmento por [RR 1,27 (95% IC 1,01-1,60), p = 0,040]. Conclusiones: Los nomogramas de carga de placa ateroesclerótica global ajustados por edad aplicados a la TC de tórax convencional fueron predictores de mortalidad.Background: Coronary artery calcification, of established predictive value, can be assessed by conventional chest computed tomography (CT). Objective: To assess the prognostic value of nomograms for global plaque burden applied to data obtained by conventional chest CT scan. Methods: Consecutive patients between 40 and 74 years undergoing clinically indicated conventional chest CT scan at our institution were included between August and December 2012. The presence and extent of coronary artery calcifications was evaluated and the patients were grouped according to age- and sex-adjusted percentiles of segment involvement score (CACSIS). Results: A total of 1,194 patients were included in the study. After a mean follow-up of 3.7±0.5 years, 53 (4.4%) patients died. There was a significant association between sex- and age-adjusted survival rates and CACSIS (RR1.27; 95% CI, 1.01-1.60, p=0.040). Conclusions: Age-adjusted nomograms for global atherosclerotic plaque burden applied to conventional chest CT scan were predictors of mortality.Fil: Rodriguez Granillo, Gaston Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; Argentina. Diagnóstico Maipú; ArgentinaFil: Reynoso, Exequiel. Diagnóstico Maipú; ArgentinaFil: Capunay, Carlos. Diagnóstico Maipú; ArgentinaFil: Deviggiano, Alejandro. Diagnóstico Maipú; ArgentinaFil: Carrascosa, Patricia. Diagnóstico Maipú; Argentin

Tomografía computarizada de doble energía: nueva tecnología para la reducción de artefactos de metal. [Dual - Energy Computed Tomography: New technology for metal artifacts reduction.]

Objetivos: Explorar la utilidad de la tomografía computada de doble energía (TCDE) mediante tecnología de imágenes espectrales gemstone (GSI) y de un software dedicado a la reducción de artefactos de metal (MARS), para la evaluación de tejidos periprotésicos e interpretabilidad diagnóstica de patologías  relacionadas con implantes. Materiales y Métodos: Se estudió la densidad ósea, partes blandas y grasa en el tejido periprotésico comparado con tejido control sin implante, utilizando un escáner de alta definición de TCDE-GSI tanto en imágenes policromáticas convencionales (PI)  y monocromáticas virtuales (VMSI) con MARS en 80 pacientes con prótesis metálicas en diversas regiones musculo-esqueléticas. Se valoró también la calidad de imagen y la interpretabilidad diagnóstica mediante escala de Likert. Resultados: Con PI se observaron diferencias significativas entre el área periprotésica en los tres tipos de tejidos evaluados  respecto a los controles (p<0.0001); sin diferencias significativas utilizando VMSI-MARS (p=0.053 hueso, p=0.32 partes blandas, y p=0.13 grasa), demostrando mayor similitud con el tejido normal. Además, los niveles de ruido de las imágenes (DS) fueron significativamente mayores con PI (p<0.0001) que con VMSI-MARS. Todas las regiones periprotésicas se consideraron no interpretables utilizando PI comparado con  11 (9%) utilizando VMSI-MARS. No hubo diferencias significativas en la dosis de radiación comparado con un grupo control pareado por sexo y edad (p= 0.21). Conclusiones: La tecnología TCDE tiene la capacidad de reducir los artefactos periprotésicos, logrando un significativo incremento en la capacidad de identificación de tejidos e interpretabilidad diagnóstica de posibles patologías relacionadas con implantes

Role of Iterative Reconstruction Algorithm for the Assessment of Myocardial Infarction with Dual Energy Computed Tomography

Rationale and Objectives: Low monochromatic energy levels (40 keV) derived from delayed enhancement dual energy cardiac computed tomography (DE-DECT) allow the evaluation of myocardial infarcts (MI) among stable patients, although at the expense of high image noise. We explored whether the application of adaptive statistical iterative reconstruction (ASIR) to 40-keV DE-DECT (unavailable with previous software versions) might improve image quality and detection of MI in stable patients. Materials and Methods: We prospectively enrolled patients with a history of previous MI, and performed delayed-enhancement cardiac magnetic resonance (DE-CMR) and DE-DECT within the same week. DE-DECT images were reconstructed with 0% and 60% ASIR. Results: MI was identified in 18 (80%) patients with both DE-CMR and DE-DECT. On a per segment basis, we did not identify significant differences regarding the diagnostic performance of DE-DECT with and without ASIR [area under receiver operating characteristic curve 0.86 vs. 0.83, p = 0.10]. The application of ASIR improved the signal-to-noise ratio of DE-DECT with 0% ASIR compared to DE-DECT with 60% ASIR (6.07 ± 2.1 vs. 11.1 ± 4.5, p < 0.0001). However, qualitative assessment of MI image quality (3.35 ± 1.2, vs. 3.55 ± 1.1, p = 0.10) and diagnostic confidence (4.40 ± 0.9 vs. 4.60 ± 0.8, p = 0.10) were not significantly improved. Using DE-DECT with 60% ASIR, a threshold over 199 HU showed a sensitivity of 67% and a specificity of 92% for the detection of segments with MI. Conclusion: In this study, DE-DECT allowed accurate detection of MI among stable patients compared with DE-CMR, and the application of ASIR improved signal-to-noise ratio of DE-DECT, although the diagnostic performance showed only non-significant improvements.Fil: Rodriguez Granillo, Gaston Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; ArgentinaFil: Deviggiano, Alejandro. Diagnostico Maipu, Buenos Aires; ArgentinaFil: Capunay, Carlos. Diagnostico Maipu, Buenos Aires; ArgentinaFil: De Zan, Macarena. Diagnostico Maipu, Buenos Aires; ArgentinaFil: Fernandez Pereira, Carlos. Sanatorio "Otamendi y Miroli S.A.". Servicio de Diagnóstico por Imágenes. Departamento de Imágenes en Cardiología. Centro de Investigaciones Cardiovasculares; ArgentinaFil: Carrascosa, Patricia. Diagnostico Maipu, Buenos Aires; Argentin

Reproducibility of Gadolinium Enhancement Patterns and Wall Thickness in Hypertrophic Cardiomyopathy

Abstract Background: Reproducibility data of the extent and patterns of late gadolinium enhancement (LGE) in hypertrophic cardiomyopathy (HCM) is limited. Objective: To explore the reproducibility of regional wall thickness (WT), LGE extent, and LGE patterns in patients with HCM assessed with cardiac magnetic resonance (CMR). Methods: The extent of LGE was assessed by the number of segments with LGE, and by the total LV mass with LGE (% LGE); and the pattern of LGE-CMR was defined for each segment. Results: A total of 42 patients (672 segments) with HCM constituted the study population. The mean WT measurements showed a mean difference between observers of -0.62 ± 1.0 mm (6.1%), with limits of agreement of 1.36 mm; -2.60 mm and intraclass correlation coefficient (ICC) of 0.95 (95% CI 0.93-0.96). Maximum WT measurements showed a mean difference between observers of -0.19 ± 0.8 mm (0.9%), with limits of agreement of 1.32 mm; -1.70 mm, and an ICC of 0.95 (95% CI 0.91-0.98). The % LGE showed a mean difference between observers of -1.17 ± 1.2 % (21%), with limits of agreement of 1.16%; -3.49%, and an ICC of 0.94 (95% CI 0.88-0.97). The mean difference between observers regarding the number of segments with LGE was -0.40 ± 0.45 segments (11%), with limits of agreement of 0.50 segments; -1.31 segments, and an ICC of 0.97 (95% CI 0.94-0.99). Conclusions: The number of segments with LGE might be more reproducible than the percent of the LV mass with LGE

Regional differences of fat depot attenuation using non-contrast, contrast-enhanced, and delayed-enhanced cardiac CT

Background: Regional fat density assessed by computed tomography (CT) has been suggested as a marker of perivascular adipose tissue inflammation. Dual energy CT (DECT) allows improved tissue characterization compared to conventional CT. Purpose: To explore whether DECT might aid regional fat density discrimination. Material and Methods: We included patients who had completed a non-enhanced cardiac CT scan, CT coronary angiography (CTCA), and a delayed enhancement CT. Attenuation levels (Hounsfield units [HU]) were assessed at the epicardial, paracardial, visceral, and subcutaneous fat. The number of coronary segments with disease (SIS) was calculated. Results: A total of 36 patients were included in the analysis. Twenty-six (72%) patients had evidence of obstructive disease at CCTA and 25 (69%) patients had evidence of previous myocardial infarction. At non-contrast CT, we did not identify significant attenuation differences between epicardial, paracardial, subcutaneous, and visceral fat depots (−110.8 ± 9 HU, vs. −113.7 ± 9 HU, vs. −114.7 ± 8 HU, vs. −113.8 ± 11 HU, P = 0.36). Significant attenuation differences were detected between fat depots at mid and low energy levels, both at CTCA and delayed-enhancement scans (P < 0.05 for all). Epicardial fat showed the least negative attenuation, irrespective of the acquisition mode; epicardial fat evaluated at 40 keV was related to the SIS (r = 0.37, P = 0.03). Conclusions: In this study, regional fat depots amenable to examination during thoracic CT scans have distinctive regional attenuation values. Furthermore, such differences were better displayed using contrast-enhanced monochromatic imaging at low energy levels.Fil: Rodriguez Granillo, Gaston Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Cardiológicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiológicas; ArgentinaFil: Capunay, Carlos. No especifíca;Fil: Deviggiano, Alejandro. No especifíca;Fil: De Zan, Macarena. No especifíca;Fil: Carrascosa, Patricia. No especifíca