RESUMEN
The treatment of advanced, drug resistant congestive heart failure gains in importance in the field of cardiac surgery. Cardiac imaging for preoperative assessment and follow-up focuses on the determination of ventricular volumes and function as well as on the detection of postoperative complications. Computed tomography (CT) is highly accurate irrespective of the individual patient's anatomic situation, has a low examiner dependence and short examination time, does not require an arterial vascular access and can be performed in patients with metal implants. CT is the modality of choice in the follow-up of heart transplants to detect extracardiac and cardiac complications including coronary calcifications as an early sign of transplant vasculopathy. In addition, CT visualizes the elements of mechanical assist devices and can identify their possible local cardiac and mediastinal complications. CT can detect fibrolipomatous involution of the mobilized muscle flap in dynamic cardiomyoplasty and can depict fibrous reactions along the epicardial mesh implant in passive cardiac containment. Further indications include assessment of typical local postoperative complications, such as intrathoracic infection and mediastinal bleeding, intracardiac thrombus formation or pericardial effusion. CT is routinely used for evaluating bypass patency but is limited in assessing associated valve defects since it does not visualize flow.
Asunto(s)
Procedimientos Quirúrgicos Cardiovasculares/métodos , Insuficiencia Cardíaca/diagnóstico por imagen , Insuficiencia Cardíaca/cirugía , Cuidados Posoperatorios/métodos , Cuidados Preoperatorios/métodos , Cirugía Asistida por Computador/métodos , Tomografía Computarizada por Rayos X/métodos , Ensayos Clínicos como Asunto , Humanos , Guías de Práctica Clínica como Asunto , Pautas de la Práctica en Medicina , Pronóstico , Medición de Riesgo/métodos , Factores de Riesgo , Resultado del TratamientoRESUMEN
Electron beam tomography (EBT) has been scientifically evaluated to a much lesser degree for non-cardiac indications than for cardiac purposes. Therefore, four groups of investigators in Berlin (2), Mannheim and Munchen, which were supported by the Deutsche Forschungsgemeinschaft (DFG), included applications outside the heart in their evaluation of EBT technology. EBT has proven useful to look for pulmonary embolism and to assess other vessels (aorta, aortic branches, and intracranial arteries). Imaging of the lung parenchyma benefits from its intrinsic high contrast and from the fast data acquisition of EBT. Limited photon efficiency, higher radiation exposure, increased noise levels and other artifacts, however, markedly reduce the value of EBT for imaging of low contrast objects compared to conventional spiral CT and multislice CT (MSCT), compromising, in particular, the morphologic depiction of parenchymal abdominal organs and the brain. Consequently, scientific studies to further evaluate EBT for scanning of the brain and parenchymal abdominal organs were not pursued. Radiation exposure for non-cardiac EBT studies is up to three times higher than that for respective spiral CT studies, and in children EBT can only be advocated in select cases. Radiation exposure for the various prospectively triggered cardiac examination protocols of EBT is lower than that for conventional coronary angiography. Radiation exposure in cardiac multislice CT exceeds severalfold that of EBT, but the dose efficiency of EBT and MSCT are similar due to higher spatial resolution and less image noise of MSCT. In addition, modifications of MSCT (ECG pulsing) can further reduce radiation exposure to the level of EBT. Technical improvements of the EBT successor scanner "e-Speed" enable faster data acquisition at higher spatial resolution. Within comparative studies, the "e-Speed" will have to prove its value and competitiveness, particularly in comparison with multislice CT. After profound scientific assessment in a multicenter evaluation supported by the Deutsche Forschungsgemeinschaft (DFG) and regardless of the specific suitability of electron beam tomography for various cardiac and some non-cardiac indications, the investigators unanimously find the electron beam tomograph Evolution C150 XP not suitable as a whole body CT scanner.
Asunto(s)
Radiografía Abdominal , Radiografía Torácica , Tomografía Computarizada Espiral , Tomografía Computarizada por Rayos X , Factores de Edad , Anciano , Investigación Biomédica , Niño , Angiografía Coronaria , Femenino , Alemania , Cardiopatías/diagnóstico por imagen , Humanos , Recién Nacido , Masculino , Estudios Multicéntricos como Asunto , Embolia Pulmonar/diagnóstico por imagen , Dosis de Radiación , Tomografía Computarizada Espiral/efectos adversos , Tomografía Computarizada Espiral/métodos , Tomografía Computarizada por Rayos X/efectos adversos , Tomografía Computarizada por Rayos X/métodos , Enfermedades Vasculares/diagnóstico por imagenRESUMEN
PURPOSE: To compare the visual analysis of magnetic resonance imaging (MRI) with the tagging technique and Doppler tissue echocardiography with invasive ventriculography in detecting and quantifying regional left ventricular wall motion abnormalities. MATERIALS AND METHODS: Sixteen patients with coronary artery disease and a history of prior myocardial infarction underwent invasive ventriculography, Doppler tissue echocardiography and MR-tagging within one week. Regional wall motion abnormalities (WMA) were detected in all patients. WMA were graded as normal = 1; hypokinetic = 2; akinetic = 3; or dyskinetic = 4. For agreement between MRI, echocardiography, and ventriculography the kappa coefficient (kappa) according to Cohen was calculated. RESULTS: The kappa coefficient (kappa) was 0.962 for agreement between MRI and echocardiography and 0.602 for agreement between MRI and ventriculography as well as between echocardiography and ventriculography. CONCLUSION: Reliable analysis of regional left ventricular wall motion abnormalities is feasible using visual analysis of MR-tagging. MRI and Doppler tissue echocardiography detect more WMA than invasive ventriculography and grade them as more severe.
Asunto(s)
Enfermedad Coronaria/diagnóstico , Ecocardiografía Doppler , Corazón/fisiopatología , Imagen por Resonancia Cinemagnética/métodos , Anciano , Angiografía Coronaria , Enfermedad Coronaria/diagnóstico por imagen , Enfermedad Coronaria/fisiopatología , Diástole , Electrocardiografía , Femenino , Frecuencia Cardíaca , Ventrículos Cardíacos/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Contracción Miocárdica , Análisis de Regresión , Sensibilidad y Especificidad , Sístole , Ultrasonografía Doppler en ColorRESUMEN
Electron beam tomography (EBT) directly competes with other non-invasive imaging modalities, such as multislice computed tomography, magnetic resonance imaging, and echocardiography, in the diagnostic assessment of cardiac diseases. EBT is the gold standard for the detection and quantification of coronary calcium as a preclinical sign of coronary artery disease (CAD). Its standardized examination protocols and the broad experience with this method favor EBT. First results with multislice CT indicate that this new technology may be equivalent to EBT for coronary calcium studies. The principal value of CT-based coronary calcium measurements continues to be an issue of controversy amongst radiologists and cardiologists due to lack of prospective randomized trials. Coronary angiography with EBT is characterized by a high negative predictive value and, in addition, may be indicated in some patients with manifest CAD. It remains to be shown whether coronary angiography with multislice CT is reliable and accurate enough to be introduced into the routine work-up, to replace some of the many strictly diagnostic coronary catheterizations in Germany and elsewhere. Assessment of coronary stent patency with EBT is associated with several problems and in our opinion cannot be advocated as a routine procedure. EBT may be recommended for the evaluation of coronary bypasses to look for bypass occlusions and significant stenoses, which, however, can be equally well achieved with multislice CT. Quantification of myocardial perfusion with EBT could not replace MRI or other modalities in this field. EBT has proven to be accurate, reliable and in some instances equivalent to MRI, which is the gold standard for the quantitative and qualitative evaluation of cardiac function. Some disadvantages, not the least of which is the limited distribution of electron beam scanners, favor MRI for functional assessment of the heart.
Asunto(s)
Angiografía Coronaria , Puente de Arteria Coronaria , Enfermedad Coronaria/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Adulto , Anciano , Angioplastia Coronaria con Balón , Calcinosis/diagnóstico por imagen , Cateterismo Cardíaco , Enfermedad Coronaria/diagnóstico , Femenino , Oclusión de Injerto Vascular/diagnóstico , Oclusión de Injerto Vascular/diagnóstico por imagen , Corazón/fisiología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , StentsRESUMEN
PURPOSE: To evaluate multi-slice spiral computed tomography (MSCT) for measurements of left ventricular volumes, ejection fraction (EF), and myocardial mass in comparison with electron beam CT (EBCT) as a reference method. MATERIAL AND METHODS: Six minipigs underwent both standardized contrast-enhanced MSCT (effective acquisition time per cardiac cycle 125.7+/-30.1 ms, reconstructed slice thickness 8 mm) and EBCT (acquisition time 50 ms, collimated slice thickness 8 mm). The contrast-to-noise ratio of the left ventricle was measured in each animal, and the contour sharpness of the myocardium was analyzed. Volumes (EDV, ESV, SV) ejection fraction (EF), and muscle mass were calculated by MSCT and by EBCT using the slice summation method. RESULTS: MSCT had a higher contrast-to-noise ratio and delineated the myocardial contours more sharply than EBCT. There was a close linear correlation between both modalities for all parameters (EDV: rP=0.88, ESV: rP=0.91, SV: rP=0.85, EF: rP=0.93; mass: rP=0.90; P<0.05 each). MSCT slightly overestimated ESV and slightly underestimated SV and EF compared with EBCT (P<0.05 each). CONCLUSIONS: Image quality in MSCT is superior to that of EBCT. Functional parameters correlate well between both modalities, but the accuracy of MSCT is limited by its lower temporal resolution.
Asunto(s)
Ventrículos Cardíacos/anatomía & histología , Ventrículos Cardíacos/diagnóstico por imagen , Volumen Sistólico , Tomografía Computarizada Espiral , Función Ventricular Izquierda , Animales , Modelos Animales , Porcinos , Porcinos Enanos , Tomografía Computarizada por Rayos XRESUMEN
PURPOSE: To evaluate the efficacy of passive cardiomyoplasty with the determination of biventricular volumes, global systolic function as well as left-ventricular muscle mass. MATERIALS AND METHODS: In 19 patients with congestive heart failure of idiopathic or ischemic origin, a polyester mesh-graft was implanted around both ventricles for stabilization and functional support. Before and three months after surgery, 15 patients underwent EBCT and 4 patients with impaired renal function underwent MRI, for the evaluation of the volume and ejection fraction of both ventricles. RESULTS: EBCT demonstrated a decrease from 385 to 310 ml in LV-EDV, from 312 to 242 ml in LV-ESV, from 209 to 160 ml in RV-EDV and from 149 to 87 ml in RV-ESV, and an increase from 20 to 26% in LV-EF and from 37 to 50% in RV-EF as well as a reduction of LV-MM from 300 to 274 g (p < 0.05 each). Similar results were obtained by MRI. CONCLUSION: Following passive cardiomyoplasty, EBCT and MRI revealed an improvement of the global systolic function as well as a reduction of biventricular volumes and left-ventricular muscle mass.
Asunto(s)
Volumen Cardíaco/fisiología , Cardiomiopatía Dilatada/cirugía , Enfermedad Coronaria/cirugía , Insuficiencia Cardíaca/cirugía , Imagen por Resonancia Cinemagnética , Complicaciones Posoperatorias/diagnóstico , Tomografía Computarizada por Rayos X , Disfunción Ventricular Izquierda/cirugía , Disfunción Ventricular Derecha/cirugía , Adulto , Anciano , Cardiomiopatía Dilatada/diagnóstico , Cardiomiopatía Dilatada/fisiopatología , Enfermedad Coronaria/diagnóstico , Enfermedad Coronaria/fisiopatología , Femenino , Estudios de Seguimiento , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/fisiopatología , Ventrículos Cardíacos/patología , Ventrículos Cardíacos/fisiopatología , Ventrículos Cardíacos/cirugía , Hemodinámica/fisiología , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/fisiopatología , Estudios Prospectivos , Implantación de Prótesis , Mallas Quirúrgicas , Disfunción Ventricular Izquierda/diagnóstico , Disfunción Ventricular Izquierda/fisiopatología , Disfunción Ventricular Derecha/diagnóstico , Disfunción Ventricular Derecha/fisiopatologíaRESUMEN
PURPOSE: To evaluate the potential of multisegmental reconstruction and variable gantry rotation time for reducing motion-induced artifacts in coronary artery imaging by multislice helical CT. MATERIALS AND METHODS: The data sets of 20 patients (8 with HR < 60 bpm, 12 with HR > 60 bpm) were analyzed. The patients underwent multislice helical CT (Aquilion 8, Toshiba, Otawara, Japan) using the following parameters: 0.5 mm slice thickness, 250 mA, 120 kV, pitch of 0.25 and variable gantry rotation times of 400, 500, or 600 msec. Images were generated by halfscan and multisegmental reconstruction. In 9 coronary segments of each patient, the presence and severity of motion artifacts were assessed and graded on a scale between 5 (no artifacts) and 1 (heaviest artifacts). RESULTS: Diagnostically relevant motion artifacts were rare at low heart rates (< 60 bpm) for both types of image reconstruction (4 % of all segments). Higher heart rates (> 60 bpm) were associated with an increase in motion artifacts on halfscan reconstructions (33% of all segments, p < 0.05) but not on multisegmental reconstructions (4% of all segments). At low heart rates mean image quality did not differ between multisegmental and halfscan reconstruction (4.28 +/- 0.37 vs. 4.22 +/- 0.41; p > 0.05), whereas at higher heart rates image quality was better for multisegmental reconstruction than for halfscan reconstruction (4.23 +/- 0.47 vs. 3.11 +/- 0.63; p < 0.05). CONCLUSION: Multisegmental reconstruction with variable gantry rotation times suppresses motion artifacts and thus improves assessment of the coronary arteries in patients with higher heart rates.
Asunto(s)
Angiografía Coronaria/métodos , Enfermedad Coronaria/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos , Imagenología Tridimensional/métodos , Tomografía Computarizada Espiral/métodos , Artefactos , Electrocardiografía , Frecuencia Cardíaca , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Sensibilidad y Especificidad , Programas InformáticosRESUMEN
PURPOSE: To determine the incidence of acute pulmonary emboli extending across the bifurcation of the main pulmonary artery, lobar arteries or segmental arteries (interpulmonary, interlobar or intersegmental saddle emboli, respectively). METHODS: 128 patients with clinically suspected acute pulmonary embolism underwent electron beam tomography (EBT). 140 scans were acquired in the continuous volume scanning mode (3 mm slice thickness). 100 ml of contrast material were intravenously administered. Studies were reviewed for the presence of acute pulmonary embolism and the number and location of interpulmonary, interlobar or intersegmental saddle emboli. Saddle emboli were defined as emboli extending across the bifurcation of a vessel into both branches by at least 5 mm each. RESULTS: 30 of 128 (23.4 %) patients (15 men; mean age 59 +/- 17 years) had acute pulmonary embolism. One or more saddle emboli were present in 20 of 30 patients (66.7 %), a total of 77 saddle emboli were detected ranging from 1 to 10 per patient. Distribution of the saddle emboli in the 20 patients was as follows: 5 interpulmonary, 28 interlobar and 44 intersegmental. CONCLUSIONS: Pulmonary saddle emboli are present in the majority of patients with acute pulmonary embolism. They are often multiple and may be found at different levels of the pulmonary arterial vasculature.
Asunto(s)
Embolia Pulmonar/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Enfermedad Aguda , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Arteria Pulmonar/diagnóstico por imagen , Sensibilidad y EspecificidadRESUMEN
Electron beam tomography (EBT) may be compromised by rib artifacts. Two hundred forty-seven abdominal studies were performed without (Group A, n = 222) or with (Group B, n = 25) the cone beam algorithm. One hundred eighty-six (83.8%) and nine (36%) studies of Groups A and B, respectively, displayed some level of artifact. In Groups A and B, major, minor, and no artifacts were found in 115 (51.5%) and 0 (0%), 71 (32.3%) and 9 (36%), and 36 (16.2%) and 16 (64%) patients, respectively (p < 0.01). The cone beam algorithm improves EBT studies of the abdomen.
Asunto(s)
Algoritmos , Costillas/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Artefactos , Distribución de Chi-Cuadrado , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Estadísticas no ParamétricasRESUMEN
AIM: To evaluate the role of cine magnetic resonance imaging (MRI) in the preoperative assessment and postoperative follow-up of patients undergoing left ventricular (LV) reduction surgery. PATIENTS AND METHODS: 6 patients with cardiomegaly were examined on a 1.5 T MR imager before and after LV reduction surgery. The heart was imaged along the short and long axes using a breath-hold ECG-triggered cine gradient-echo sequence for assessing ventricular and valvular morphology and function and performing volumetry (end-diastolic and end-systolic volumes, ejection fraction). RESULTS: Postoperatively, the mean ejection fraction increased from 21.7% to 33.4% and the end-diastolic and end-systolic left ventricular volumes decreased in all patients (304.0 and 252.5 ml before to 205.0 and 141.9 ml after surgery). Mean myocardial mass decreased slightly from 283.8 g to 242.7 g. Differences were significant for all parameters (p < 0.05). MRI allowed for the reliable assessment of post-operative valve morphology and yielded additional findings such as the presence of mitral valve insufficiency or ventricular thrombus. CONCLUSIONS: Cine MRI provides relevant information prior to left ventricular reduction surgery and reliably depicts functional and morphological changes in the early post-operative follow-up.
Asunto(s)
Cardiomegalia/cirugía , Ventrículos Cardíacos/cirugía , Imagen por Resonancia Cinemagnética , Anciano , Cardiomegalia/diagnóstico , Electrocardiografía , Femenino , Estudios de Seguimiento , Cardiopatías/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Insuficiencia de la Válvula Mitral/diagnóstico , Complicaciones Posoperatorias/diagnóstico , Volumen Sistólico , Trombosis/diagnóstico , Factores de TiempoAsunto(s)
Neoplasias Cardíacas/diagnóstico por imagen , Ventrículos Cardíacos/diagnóstico por imagen , Lipoma/diagnóstico por imagen , Recurrencia Local de Neoplasia/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Adulto , Femenino , Neoplasias Cardíacas/cirugía , Ventrículos Cardíacos/cirugía , Humanos , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Lipoma/cirugía , Recurrencia Local de Neoplasia/cirugíaRESUMEN
In 45 patients with coronary bypass grafts, the breath-hold interval with and that without preoxygenation was measured. Its effect on depiction of the distal graft anastomosis at electron-beam tomography was evaluated. Preoxygenation prolonged the breath-hold interval in most patients, thereby allowing greater anatomic coverage including more distal anastomoses. Preoxygenation may improve scanning of coronary bypass grafts and increase detectability of graft stenoses.
Asunto(s)
Puente de Arteria Coronaria , Enfermedad Coronaria/diagnóstico por imagen , Enfermedad Coronaria/cirugía , Tomografía Computarizada por Rayos X/métodos , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oxígeno/administración & dosificación , Respiración , Estadísticas no ParamétricasRESUMEN
PURPOSE: Comparative volumetric assessment of the left ventricle by magnetic resonance imaging (MRI) and electron beam tomography (EBT) in patients with ischemic and dilated cardiac disease. METHODS: Thirty-two patients underwent cine MRI and EBT in the multislice mode. All studies were triggered to the ECG. Left ventricular ejection fraction (EF), end-diastolic (EDV) and end-systolic volume (ESV), and myocardial mass (MM) were determined by 3D-volumetry by MRI and EBT and results were compared. RESULTS: The correlation between MRI and EBT for EF, EDV, ESV, and MM were r = 0.86, r = 0.95, r = 0.95, and r = 0.93, respectively. CONCLUSIONS: There is an excellent correlation between MRI and EBT in determining left-ventricular parameters. Both methods are suitable for volumetric assessment of the left ventricle.