Pulmonary arteries: MR imaging in patients with congenital obstruction of the right ventricular outflow tract

Thirty-five patients with congenital obstruction of the right ventricular outflow tract underwent magnetic resonance (MR) imaging for evaluation of the pulmonary arteries. All patients underwent cardiac catheterization, and 33 underwent two-dimensional Doppler echocardiography. Results of the three imaging studies were compared. With regard to the presence of a pulmonary confluence, results of MR imaging and angiography were in agreement in 31 of the 35 patients (89%), results of echocardiography and MR imaging were in agreement in 27 of 33 patients (82%), and results of echocardiography and angiography were in agreement in 27 of 33 patients (82%). There was good correlation of measurements of main pulmonary artery size among all three methods and of right and left pulmonary artery size obtained at MR imaging and angiography. Echocardiographic measurements of right and left pulmonary artery size correlated poorly with those obtained at MR imaging and angiography. Results indicated that MR imaging is useful in evaluating the pulmonary arteries in patients with congenital heart disease.     

64层CT对先天性心脏病肺动脉发育异常的术前评价

目的 前瞻性研究64层CT心血管造影评价先天性心脏病肺动脉发育异常的可行性和准确性. 资料与方法对心脏超声诊断先天性心脏病并临床怀疑有肺动脉发育异常的49例患儿于手术前7天内行64层CT心血管造影榆查.对所有各向同性扫描的薄层图像行任意方向多平面重组(MPR)及容积再现(VR)重组以显示肺动脉形态及密度,并与手术所见对照分析.结果 49例先天性心脏病患儿术前心血管CT造影诊断肺动脉发育异常42例,其中肺动脉扩张6例,肺动脉广泛变细8例,肺动脉局限性狭窄18例,肺动脉闭锁6例,肺动脉部分缺如4例.与手术结果对照,64层CT造影诊断肺动脉发育异常的敏感性为96.2%,特异性为99.3%,阳性预测值为96.2%,阴性预测值为99.3%,准确性为98.8%.结论 64层CT心血管造影是评价先天性心脏病肺动脉发育异常的可行和准确的方法.     

MR imaging and CT of vascular anomalies and connections in patients with congenital heart disease: significance in surgical planning.

To plan effective management of congenital heart disease, one needs the clearest understanding of the anatomy. Although echocardiography and angiography are the dominant imaging modalities in patients with congenital heart disease, magnetic resonance (MR) imaging and computed tomography (CT) are valuable noninvasive adjuncts. MR imaging and CT are effective in demonstrating the complex cardiovascular morphology present in congenital heart disease, especially the extracardiac morphology. In patients with tetralogy of Fallot with complex pulmonary artery anatomy, MR imaging and CT are useful in demonstrating the pulmonary artery anatomy, along with the significant aortopulmonary collateral vessels. In the heterotaxy syndromes, patients often have unusual atriovenous connections. MR imaging allows accurate identification of the hepatic, systemic, and pulmonary veins and their relationships to both atria. CT and MR are the imaging modalities of choice in a patient who is thought to have a vascular ring. Treatment of aortic coarctation is usually performed on the basis of typical clinical and echocardiographic findings. In patients with atypical clinical or echocardiographic findings, MR imaging and CT yield helpful information that can change the treatment plan. The enhanced preoperative understanding of congenital heart disease provided by MR imaging and CT simplifies surgical decision making and consequently may improve outcome.     

Disparity between ratios of diameters and blood flows in central pulmonary arteries in postoperative congenital heart disease using MRI

PURPOSE: To compare the relative severity of stenoses of right or left pulmonary arteries with differences in flow to each lung after repair of congenital heart disease (CHD). MATERIALS AND METHODS: A total of 15 patients with postoperative congenital heart disease underwent MRI to evaluate branch pulmonary artery stenoses. Spin-echo images and MR angiography were used to assess morphology, and velocity-encoded cine (VEC) MRI was used to measure flow in the right and left pulmonary arteries. The ratios of the narrowest diameters of the right to left pulmonary arteries (R/L size) and right to left pulmonary arterial flow (R/L flow) were compared using Spearman's correlation. F test was used to assess the significance of the regression coefficients. RESULTS: R/L size ratio varied from 0.50 to 2.66, while the R/L flow ratio varied from 0.36 to 12.02. There was an exponential relationship between R/L size and R/L flow, with r2=0.78 and P=0.001. However, severity of morphologic stenoses was not clinically useful for predicting flow reduction. Prediction residuals ranged from -136% to 54% of the true R/L flow. CONCLUSION: Anatomical evaluation of the pulmonary arteries does not predict accurately differential blood flow in patients with pulmonary stenoses. Therefore, blood flow measurements are essential when considering the need for further surgical or interventional procedures.     

复杂先天性心脏病手术后磁共振检查

目的 评价磁共振对手术后复杂先天性心脏病的诊断价值和检查技术。资料与方法 75例手术后复杂先天性心脏病作了磁共振检查，扫描序列为自旋回波T1WI序列，梯度回波电影序列和造影增强的磁共振血管成像序列。结果 75例中，法洛四联症等病变作右室流出道补片25例，其中7例补片远端吻合口狭窄，23例为Fontan或Glenn一类手术后，5例吻合口有梗阻。12例为主动脉弓病变术后，3例有残余梗阻，75例磁共振均清晰显示术后改变。结论 磁共振对手术后复杂先心病有很高的诊断价值，其中造影增强的磁共振血管成像序列必不可少。放射科医生熟悉手术方法对检查十分重要。     

Quantification of flow dynamics in congenital heart disease: applications of velocity-encoded cine MR imaging.

Velocity-encoded cine (VEC) magnetic resonance (MR) imaging is a valuable technique for quantitative assessment of flow dynamics in congenital heart disease (CHD). VEC MR imaging has a variety of clinical applications, including the measurement of collateral flow and pressure gradients in coarctation of the aorta, differentiation of blood flow in the left and right pulmonary arteries, quantification of shunts, and evaluation of valvular regurgitation and stenosis. After surgical repair of CHD, VEC MR imaging can be used to monitor conduit blood flow, stenosis, and flow dynamics. There are some pitfalls that can occur in VEC MR imaging. These include potential underestimation of velocity and flow, aliasing, inadequate depiction of very small vessels, and possible errors in pressure gradient measurements. Nevertheless, VEC MR imaging is a valuable tool for preoperative planning and postoperative monitoring in patients with CHD.     

Congenital thoracic vascular anomalies: evaluation with state-of-the-art MR imaging and MDCT

Congenital thoracic vascular anomalies include embryologic developmental disorders of the thoracic aorta, aortic arch branch arteries, pulmonary arteries, thoracic systemic veins, and pulmonary veins. Diagnostic evaluation of these anomalies in pediatric patients has evolved with innovations in diagnostic imaging technology. State-of-the-art magnetic resonance (MR) imaging, MR angiography multidetector-row computed tomographic (MDCT) angiography, and advanced postprocessing visualization techniques offer accurate and reliable high-resolution two-dimensional and three-dimensional noninvasive anatomic displays for interpretation and clinical management of congenital thoracic vascular anomalies. This article reviews vascular MR imaging, MR angiography, MDCT angiography, and advanced visualization techniques and applications for the assessment of congenital thoracic vascular anomalies, emphasizing clinical embryology and the characteristic imaging findings.     

Congenital heart diseases: post-operative appearance on multi-detector CT—a pictorial essay

Echocardiography is considered as an initial imaging modality of choice in patients with congenital heart disease (CHD), and magnetic resonance (MR) imaging is preferred for detailed functional information. Multi-detector computed tomography (CT) plays an important role in clinical practice in assessing post-operative morphological and functional information of patients with complex CHD when echocardiography and MR imaging are not contributory. Radiologists should understand and become familiar with the complex morphology and physiology of CHD, as well as with various palliative and corrective surgical procedures performed in these patients, to obtain CT angiograms with diagnostic quality and promptly recognise imaging features of normal post-operative anatomy and complications of these complex surgeries.     

MR imaging of unilateral pulmonary artery anomalies

Magnetic resonance (MR) imaging of the pulmonary arteries was performed in seven children with unilateral pulmonary artery abnormalities. Five had congenital absence or interruption of a pulmonary artery; two had postsurgical occlusion or narrowing of a pulmonary artery. A small patent hilar pulmonary artery was identified in one of the five cases of congenital pulmonary artery interruption or absence. Occluding thrombus was identified in the right pulmonary artery of one child following pulmonary artery banding. In another case marked narrowing of the right pulmonary artery was identified secondary to migration of a pulmonary artery band. The MR findings were confirmed by angiography in all cases. Magnetic resonance appears to be a useful noninvasive modality for accurate anatomic depiction of unilateral pulmonary artery abnormalities in childhood. It may be especially valuable for diagnosis of pulmonary artery stenosis or occlusion following surgical treatment of congenital heart disease.     

MR Imaging of Congenital Heart Diseases in Adolescents and Adults

Echocardiography and catheterization angiography suffer certain limitations in the evaluation of congenital heart diseases in adults, though these are overcome by MRI, in which a wide field-of view, unlimited multiplanar imaging capability and three-dimensional contrast-enhanced MR angiography techniques are used. In adults, recently introduced fast imaging techniques provide cardiac MR images of sufficient quality and with less artifacts. Ventricular volume, ejection fraction, and vascular flow measurements, including pressure gradients and pulmonary-to-systemic flow ratio, can be calculated or obtained using fast cine MRI, phase-contrast MR flow-velocity mapping, and semiautomatic analysis software. MRI is superior to echocardiography in diagnosing partial anomalous pulmonary venous connection, unroofed coronary sinus, anomalies of the pulmonary arteries, aorta and systemic veins, complex heart diseases, and postsurgical sequelae. Biventricular function is reliably evaluated with cine MRI after repair of te ralogy of Fallot, and Senning''s and Mustard''s operations. MRI has an important and growing role in the morphologic and functional assessment of congenital heart diseases in adolescents and adults.     

Repair of congenital heart disease: a primer-part 1

Advances in the surgical management of congenital heart disease have led to enhanced patient survival and quality of life. Improvements in technology in computed tomography and magnetic resonance imaging have resulted in increasing use of cross-sectional imaging in these patients. Perioperative care in these patients requires that radiologists have an understanding of the surgical treatment and the resultant postoperative anatomy. Because many of these patients with treated congenital heart disease are being followed into the 4th and 5th decades of life, this is information that will fall within the domain of the radiologist who deals with adults. This review, which is presented in two parts, covers the major surgical procedures used for the treatment of congenital heart disease, and will be presented in two parts. In part 1, median sternotomy and its complications, palliative procedures, and complex repairs are discussed.     

Die Computertomographie bei der Bildgebung von Kindern mit kongenitalen Herzvitien

Congenital heart diseases are the most common congenital abnormalities of development. In general, echocardiography and cardiac catheter angiography are considered the gold standard for the evaluation of congenital heart disease. Cardiac magnetic resonance imaging has become an important supplementary imaging modality because of its ability to provide an accurate morphological and functional evaluation. The role of cardiac computed tomography in the imaging of patients with congenital heart disease is becoming increasingly more important due to the development of low radiation dose protocols and improvements in the spatial and temporal resolution. In the preoperative depiction and follow-up after surgical repair of congenital heart diseases, cardiac computed tomography provides detailed information of the heart, the venous and arterial pulmonary circulation as well as systemic arteries. This article reviews the technical aspects of cardiac CT and the modification of examination protocols according to the expected pathology and patient age. The potentials and limitations of the various radiation dose reduction strategies are outlined.     

Pre-operative evaluation with MR in tetralogy of fallot and pulmonary atresia with ventricular septal defect

Purpose: To assess whether MR imaging could replace angiography in pre-operative evaluation of patients with tetralogy of Fallot and pulmonary atresia with ventricular septal defect (VSD), especially since the surgical correction was done earlier than was previously the rule.Material and Methods: Fourteen patients with tetralogy of Fallot (n=10) or pulmonary atresia with VSD (n=4), mean age 7.5±4.4 months, were evaluated with angiocardiography and MR before definitive surgical correction.Results: There was good diagnostic agreement between the two modalities when evaluating right ventricular outflow obstruction; 86% for valvular and 93% for supravalvular stenosis, but the agreement was somewhat lower for the subvalvular obstruction (57%). Surgery findings, however, were in favour of MR in 5 patients concerning the subvalvular right ventricular outflow tract obstruction. MR images identified all stenoses in the right and left pulmonary arteries, but overlooked one stenosis in the main pulmonary artery. MR could evaluate patency in all palliative shunts.Conclusion: Even in this young age group, MR imaging offers a good alternative to angiocardiography for the pre-operative evaluation of the right ventricular outflow tract, the main pulmonary artery and the proximal right and left pulmonary arteries, before definitive surgical correction of tetralogy of Fallot and pulmonary atresia with VSD.     

Hydatid disease of right ventricle and pulmonary arteries: a rare cause of pulmonary embolism—computed tomography and magnetic resonance imaging findings (2009: 5b)

Hydatid disease can occur anywhere in the body and can demonstrate different imaging features that vary according to growth stage, associated complications, and affected tissue. Cardiovascular system involvement of hydatid disease is very rare. In this article, we present the cardiac magnetic resonance (MR) and thorax computed tomography (CT), MR angiography (MRA) findings of hydatid cysts located in the right ventricle and pulmonary arteries after surgical removal of hepatic hydatid cysts.     

Predictors of patient response to pulmonary thromboendarterectomy

OBJECTIVE: We sought to identify imaging features that help predict surgical success in patients undergoing thromboendarterectomy. MATERIALS AND METHODS: Thirty-nine consecutive patients who underwent pulmonary angiography and thromboendarterectomy during 1995 and 1996 were included. Thirty-four underwent helical CT angiography. Measurements of postoperative pulmonary vascular resistance were compared with preoperative imaging features and preoperative pulmonary vascular resistance. RESULTS: The best imaging indicators of a relatively high postoperative pulmonary vascular resistance were the extent of small vessel disease identified on CT angiograms as segments with abnormal perfusion but normal segmental arteries (p = 0.005) and the extent of central disease (p = 0.015). Combined with preoperative pulmonary vascular resistance, these features had a strong correlation with postoperative outcome (p = 0.0005). Segmental arterial disease seen on both conventional angiography and CT angiography correlated poorly with surgical outcome. CONCLUSION: In patients with chronic thromboembolic pulmonary hypertension, CT angiographic evidence of extensive central vessel disease and limited small vessel involvement indicates a favorable surgical outcome.     

Morphologic and functional evaluation of congenital heart disease by magnetic resonance imaging.

Magnetic resonance imaging (MRI) has evolved sufficiently to be recognized as a useful complementary noninvasive method to echocardiography in the evaluation of congenital heart disease (CHD). In some cases, MRI is superior to other imaging modalities, particularly in the evaluation of thoracic aortic anomalies and in defining the anatomy of central pulmonary arteries; it is also the procedure of choice in the postoperative follow-up of patients with CHD. Recent technological advances permit not only morphological evaluation (provided by spin-echo and MR angiographic techniques) but functional and flow information (provided by fast cine-GE and velocity-encoded sequences), causing it to be recognized by pediatric cardiologists and cardiac surgeons as an unavoidable technique for pre- and postoperative evaluation of some CHD. This review describes the various techniques used in the evaluation of CHD with emphasis on recent developments as well as recognized clinical applications. J. Magn. Reson. Imaging 1999;10:639-655.     

Evaluation of congenital heart disease with MR imaging: current and coming attractions.

Nearly 10 years of experience in the use of MR imaging for the diagnosis of congenital heart disease has accumulated. Although MR imaging is superior to other techniques in showing certain structures and abnormalities such as small central pulmonary arteries in tetralogy of Fallot, aortic coarctations, and venous connections in heterotaxia syndromes, it remains an ancillary tool to echocardiography and cardiac catheterization. In this review, we examine present limitations and advantages of conventional MR in the evaluation of congenital anomalies of the heart and great vessels and explore future developments that might bring MR imaging into the diagnostic mainstream. Key improvements now in development are ultrafast MR systems for acquisition of multiple real-time MR images (in 30 msec or less) and on-line three-dimensional computer reconstruction of the heart and great vessels. Improved display and understanding of complex anatomy, as well as more extensive functional analysis of hearts before and after surgery, should be the benefits of such developments.     

Magnetic resonance imaging in congenital heart disease of newborns: preliminary results in 23 patients

Until now little attention has been paid to the potential of MR imaging in congenital heart disease of the newborn. ECG-gated MRI was therefore performed at 0.5 tesla in 23 newborns (mean age 7.5 days) with suspected congenital heart disease. Two newborns were controlled after surgery (switch, Blalock-Taussig procedure). All had undergone prior evaluation by two-dimensional Doppler echocardiography (2-D DE). MR imaging was of a satisfying quality in all but one newborn. The aim of this study was to assess complementary information provided by MRI in comparison to 2-D DE. Pre-operatively MRI missed some abnormalities shown by 2-D DE: one coartaction, one ductus arteriosus and one pulmonary atresia. MRI demonstrated lesions that echocardiography had either failed to visualize or found inconclusive, including double aortic arch (one patient), muscular ventricular septum defect (two patients) and severe ductus arteriosus (one patient). In one of the two patients with a ventricular septum defect, angiography was avoided and in the other patient it merely confirmed the MRI results. Post-operatively, MRI demonstrated information complementary to that obtained from to 2-D DE: (1) clearly visualizing the reinsertion of the coronary arteries in the 'switched' transposition of the great vessels, (2) appreciating the diameter and patency of the palliative shunt in the Blalock-Taussig procedure.     

Contributions of newer MR imaging strategies for congenital heart disease.

Magnetic resonance (MR) imaging is a valuable noninvasive adjunct in the evaluation of congenital heart disease (CHD). With its multiplanar image acquisition, good spatial resolution, and large-field-of-view image display, MR imaging can allow appreciation of vascular connections not readily apparent at echocardiography or angiography. Evaluation of CHD with MR imaging has two components: definition of cardiovascular anatomy and characterization of blood flow. However, the variety of MR imaging options is large and often confusing. Besides spin-echo and gradient-echo imaging, MR imaging techniques for evaluation of CHD include MR angiography, cine MR imaging, and flow quantification. An understanding of the potential MR imaging options enables formulation and more efficient application of MR imaging strategies. When performed well, MR imaging greatly enhances surgical planning and can even obviate cardiac catheterization. MR imaging is also an excellent modality for serial evaluation of surgical results and complications in cases of CHD.     

Abnormalities of the pulmonary veins: evaluation with MR imaging and comparison with cardiac angiography and echocardiography

Seventy-seven patients underwent T1-weighted spin-echo magnetic resonance (MR) imaging. Group 1 (n = 56) consisted of patients with various types of congenital heart disease but normal pulmonary veins. Group 2 (n = 22) consisted of patients with the following conditions: partial anomalous pulmonary venous connection (n = 11), total anomalous pulmonary venous connection (n = 5), cor triatriatum (n = 4), or pulmonary vein stenosis (n = 2). In group 1, the sites of connections of all four pulmonary veins were identified with MR imaging in 88% of cases; the connections of at least three pulmonary veins were seen in all patients. In group 2, the prospective detection rate of pulmonary venous abnormalities with MR imaging was 95%. The prospective detection rates of pulmonary venous abnormalities with cardiac angiography (n = 13) and echo-cardiography (n = 13) were 69% and 38%, respectively. This study indicates that MR imaging can accurately demonstrate the normal pulmonary veins and abnormalities of the pulmonary veins.