RESUMEN
OBJECTIVES: The purpose of this study was to evaluate image quality and radiation dose using a prospectively electrocardiogram (ECG)-triggered axial scan protocol compared with standard retrospective ECG-gated helical scanning for coronary computed tomography angiography. BACKGROUND: Concerns have been raised regarding radiation exposure during coronary computed tomography angiography. Although the use of prospectively ECG-triggered axial scan protocols may effectively lower radiation dose compared with helical scanning, it is unknown whether image quality is maintained in a clinical setting. METHODS: In a prospective, multicenter, multivendor trial, 400 patients with low and stable heart rates were randomized to either an axial or a helical coronary computed tomography angiography scan protocol. The primary endpoint was to demonstrate noninferiority in image quality with the axial scan protocol, which was assessed on a 4-point scale (1 = nondiagnostic, 4 = excellent image quality). Secondary endpoints included radiation dose and the rate of downstream testing during 30-day follow-up. RESULTS: Image quality in patients scanned with the axial scan protocol (score 3.36 ± 0.59) was not inferior compared with helical scan protocols (3.37 ± 0.59) (p for noninferiority <0.004). Axial scanning was associated with a 69% reduction in radiation exposure (dose-length product [estimated effective dose] 252 ± 147 mGy · cm [3.5 ± 2.1 mSv] vs. 802 ± 419 mGy · cm [11.2 ± 5.9 mSv] for axial vs. helical scan protocols, p < 0.001). The rate of downstream testing did not differ (13.8% vs. 15.9% for axial vs. helical scan protocols, p = 0.555). CONCLUSIONS: In patients with stable and low heart rates, the prospectively ECG-triggered axial scan protocol maintained image quality but reduced radiation exposure by 69% compared with helical scanning. Axial computed tomography data acquisition should be strongly recommended in suitable patients to avoid unnecessarily high radiation exposure.
Asunto(s)
Técnicas de Imagen Sincronizada Cardíacas , Angiografía Coronaria/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Electrocardiografía , Dosis de Radiación , Tomografía Computarizada Espiral , Argentina , Índice de Masa Corporal , Distribución de Chi-Cuadrado , Enfermedad de la Arteria Coronaria/fisiopatología , Europa (Continente) , Frecuencia Cardíaca , Humanos , Japón , Valor Predictivo de las Pruebas , Pronóstico , Factores de TiempoRESUMEN
BACKGROUND: Because of their similar visual appearance, differentiation of left ventricular thrombotic material and myocardial wall can be difficult in contrast-enhanced coronary computed tomography (CT) angiography. OBJECTIVE: We identified typical thrombi attenuation of left ventricular thrombi with the use of CT measurement. METHODS: Over a time period of 6 years, we retrospectively identified 31 patients who showed a left ventricular thrombus in CT angiography datasets. Patients underwent routine contrast cardiac CT to investigate coronary artery disease. CT attenuation of each thrombus was assessed in the 4-chamber view. CT densities were also determined in the ascending aorta, left ventricle, and myocardial wall both in the mid-septal and mid-lateral segments. The mean CT attenuation of thrombi and the difference between attenuation in thrombi, left ventricular cavity, and myocardial wall were determined. The ratio of attenuation values in thrombus versus aorta and myocardium versus aorta were also determined. RESULTS: Mean (±SD) CT attenuation of all left ventricular thrombi in 31 patients was 43.2 ± 15.3 HU (range, 25-80 HU). Mean CT densities of septal and lateral myocardial wall were 102.9 ± 23.1 HU (range, 63-155 HU) and 99.3 ± 28.7 HU (range, 72-191 HU), respectively, and were thus significantly higher than the CT attenuation of thrombi (P < 0.001). A threshold of 65 HU yielded a sensitivity, specificity, and positive and negative predictive values of 94%, 97%, 94%, and 97%, respectively, to differentiate thrombus from the myocardial wall. The mean ratio between CT attenuation of thrombus and CT attenuation within the ascending aorta was 0.11 ± 0.05 (range, 0.04-0.23), which was significantly lower compared with the mean ratio between CT attenuation of the myocardial wall and the CT attenuation within the ascending aorta. CONCLUSION: CT attenuation within left ventricular thrombi was significantly lower than myocardial attenuation in CT angiography datasets. Assessment of CT attenuation may contribute to the differentiation of thrombi.
Asunto(s)
Angiografía Coronaria/métodos , Cardiopatías/diagnóstico por imagen , Ventrículos Cardíacos/diagnóstico por imagen , Trombosis/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Anciano , Alemania , Humanos , Masculino , Miocardio/patología , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Factores de TiempoRESUMEN
OBJECTIVES: The aim of this study was to use coronary computed tomographic (CT) angiography to characterize coronary artery involvement in patients with known Takayasu arteritis who present with anginal chest pain or shortness of breath. BACKGROUND: Takayasu arteritis is a primary vasculitis of the large vessels, which mainly affects the aorta and its branches but can also involve the coronary arteries. Coronary CT angiography allows visualization of the coronary vessels and can be used to detect both stenotic and nonstenotic coronary artery lesions. METHODS: Eighteen consecutive patients with Takayasu arteritis and angina (typical or atypical) and/or dyspnea underwent contrast-enhanced 64-slice coronary CT angiography. The arterial injury was classified according to the Numano classification. Three patients had prior known coronary artery disease. Coronary arteries were evaluated concerning the presence of obstructive and nonobstructive lesions, and differences between the clinical presentations of patients with and without coronary artery involvement on CT angiography were analyzed. RESULTS: Coronary artery involvement was found in 8 patients (44.4%), 3 of them with clinical activity. A total of 19 coronary lesions were present (13 in ostial locations, 5 in proximal coronary artery segments, and 1 in a mid segment). Eight lesions exceeded 50% diameter reduction (2 in ostial locations and 6 in proximal coronary artery segments). Median disease duration was significantly different between patients with coronary artery involvement (176 months; range 13 to 282 months) compared with those without (21 months; range 1 to 142 months) (p = 0.013). CONCLUSIONS: Coronary CT angiography allows the assessment of coronary artery involvement in patients with Takayasu arteritis. These data confirm prior observations that most coronary lesions are in ostial or proximal coronary artery locations. Disease duration in patients with coronary artery involvement is longer than in patients without.
Asunto(s)
Angiografía Coronaria/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Arteritis de Takayasu/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Adulto , Angina de Pecho/etiología , Distribución de Chi-Cuadrado , Enfermedad de la Arteria Coronaria/etiología , Progresión de la Enfermedad , Disnea/etiología , Femenino , Humanos , Masculino , México , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Índice de Severidad de la Enfermedad , Arteritis de Takayasu/complicaciones , Adulto JovenRESUMEN
Improvements in image quality in cardiac computed tomography may be achieved through iterative image reconstruction techniques. We evaluated the ability of "Iterative Reconstruction in Image Space" (IRIS) reconstruction to reduce image noise and improve subjective image quality. 55 consecutive patients undergoing coronary CT angiography to rule out coronary artery stenosis were included. A dual source CT system and standard protocols were used. Images were reconstructed using standard filtered back projection and IRIS. Image noise, attenuation within the coronary arteries, contrast, signal to noise and contrast to noise parameters as well as subjective classification of image quality (using a scale with four categories) were evaluated and compared between the two image reconstruction protocols. Subjective image quality (2.8 ± 0.4 in filtered back projection and 2.8 ± 0.4 in iterative reconstruction) and the number of "evaluable" segments per patient 14.0 ± 1.2 in filtered back projection and 14.1 ± 1.1 in iterative reconstruction) were not significant different between the two methods. However iterative reconstruction had a lower image noise (22.6 ± 4.5 HU vs. 28.6 ± 5.1 HU) and higher signal to noise and image to noise ratios in the proximal coronary arteries. IRIS reduces image noise and contrast-to-noise ratio in coronary CT angiography, thus providing potential for reducing radiation exposure.
Asunto(s)
Angiografía Coronaria/métodos , Estenosis Coronaria/diagnóstico por imagen , Interpretación de Imagen Radiográfica Asistida por Computador , Tomografía Computarizada por Rayos X , Adulto , Anciano , Artefactos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Dosis de RadiaciónRESUMEN
We present the case of a 54-year-old female with a previous history of lung fibrosis secondary to methotrexate used for rheumatoid arthritis who was referred to cardiology evaluation due to precordial pain. Echocardiography showed biatrial enlargement with an enlarged coronary sinus and tubular image posterior to the heart. On the coronary angiogram, the right coronary artery was enlarged, and a distal fistula was identified. The patient underwent a contrast enhanced cardiac computed tomography which demonstrated an aneurysmatic right coronary artery with a distal fistula to the right atrium and coronary sinus. As the chest pain did not recur and there was a high risk of the intervention to correct coronary fistula, the patient remained on conservative treatment.
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Aneurisma Coronario/diagnóstico por imagen , Seno Coronario/diagnóstico por imagen , Ecocardiografía Tridimensional/métodos , Atrios Cardíacos/diagnóstico por imagen , Fístula Vascular/diagnóstico por imagen , Dolor en el Pecho/diagnóstico , Dolor en el Pecho/etiología , Aneurisma Coronario/fisiopatología , Aneurisma Coronario/terapia , Angiografía Coronaria/métodos , Seno Coronario/fisiopatología , Ecocardiografía/métodos , Ecocardiografía Doppler en Color , Femenino , Estudios de Seguimiento , Atrios Cardíacos/fisiopatología , Humanos , Persona de Mediana Edad , Monitoreo Fisiológico/métodos , Fibrosis Pulmonar/diagnóstico , Fibrosis Pulmonar/terapia , Medición de Riesgo , Índice de Severidad de la Enfermedad , Tomografía Computarizada por Rayos X/métodos , Fístula Vascular/fisiopatología , Fístula Vascular/terapiaRESUMEN
A 61-year-old female patient presented with sub acute myocardial infarction with an occluded right coronary artery on invasive evaluation and a ventricular septal rupture on echocardiogram. Cardiac computed tomography (CT) was performed to better define the septal anatomy. As the anatomy on cardiac CT was considered unfavorable for percutaneous intervention, the patient underwent successful surgical repair.
Asunto(s)
Disección Aórtica/etiología , Oclusión Coronaria/complicaciones , Aneurisma Cardíaco/etiología , Infarto de la Pared Inferior del Miocardio/etiología , Rotura Septal Ventricular/etiología , Disección Aórtica/diagnóstico , Disección Aórtica/cirugía , Procedimientos Quirúrgicos Cardíacos , Oclusión Coronaria/diagnóstico , Femenino , Aneurisma Cardíaco/diagnóstico , Aneurisma Cardíaco/cirugía , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Infarto de la Pared Inferior del Miocardio/diagnóstico , Persona de Mediana Edad , Tomografía Computarizada por Rayos X , Ultrasonografía , Rotura Septal Ventricular/diagnóstico , Rotura Septal Ventricular/cirugíaRESUMEN
A 37-year-old patient with known systemic lupus erythematous, antiphospholipid syndrome and previous pulmonary embolism presented with non-ST elevation myocardial infarction while on adequate anticoagulation therapy. The patient was further evaluated with cardiac computed tomography. A small diagonal branch occlusion was the only coronary lesion present. A partially calcified right ventricular thrombus was incidentally found. Because of the small vessel size, cardiac catheterization was deemed unnecessary, and the patient was discharged with adjustment of immunosuppressive therapy and anticoagulation.