Partial anomalous pulmonary venous return and atrial septal defect in adult patients detected with 128-slice multidetector computed tomography
- 14k Downloads
The present series describes a group of adults with left-to-right shunts including partial anomalous pulmonary venous return (PAPVR) and/or an atrial septal defect (ASD) evaluated with ECG-gated 128-slice multidetector computed tomography (MDCT). PAPVR is defined as a left-to-right shunt where one or more, but not all, pulmonary veins drain into a systemic vein or the right atrium. PAPVR involving the right upper pulmonary vein can be associated with a sinus venosus ASD. The presence, course, number of anomalous veins and associated cardiovascular defects can be reliably observed by 128-slice MDCT angiography.
KeywordsPartial anomalous pulmonary venous return (PAPVR) Atrial septal defect (ASD) Multidetector computed tomography (MDCT)
List of Abbreviations
partial anomalous pulmonary venous return
multidetector computed tomo-graphy
atrial septal defect
superior vena cava
pulmonary to systemic blood flow ratio
magnetic resonance imaging.
Partial anomalous pulmonary venous return (PAPVR) is defined as a left-to-right shunt where one or more, but not all, pulmonary veins drain into a systemic vein or the right atrium. Anomalous right-sided pulmonary veins can drain into the superior vena cava (SVC), right atrium, inferior vena cava, azygos vein, hepatic vein or portal vein. The connecting sites for anomalous left-sided pulmonary veins can be the left brachiocephalic vein, coronary sinus and hemiazygos vein. PAPVR involving the right upper pulmonary vein can be associated with a sinus venosus atrial septal defect (ASD) located near the SVC orifice .
All PAPVRs are left-to-right shunts, but unless more than 50% of the pulmonary flow drains to the right side of the heart clinical manifestations are rare. Dyspnea, fatigue, exercise intolerance, palpitations, syncope, atrial arrhythmias, right heart failure, and pulmonary hypertension may occur [2, 3].
The presence, size, and direction of an intracardiac shunt can be noninvasively and accurately evaluated with a peripheral dye dilution technique. The flow ratio of pulmonary to systemic blood flow (P/S) is used clinically to determine the significance of the shunt. The ratio of less than 1. 5 indicates a small left-to-right shunt, 1. 5-1. 9 an intermediate and 2. 0 or more a large left-to-right shunt; the latter two generally require surgical repair to prevent future complications . Although this method is sensitive and accurate in sizing the shunt, the anatomy and location of the shunt remain to be evaluated with other imaging techniques.
PAPVR is usually diagnosed by transthoracic echocardiography (TTE) or transesophageal echocar-diography (TEE) and catheter based angiography [5, 6]. However, echocardiography can provide insufficient information, mainly due to its limited acoustic window. Right heart catheterization with pulmonary angiography is an operator-dependent and invasive technique, and it may be difficult to adequately depict, in particular, the anatomy of small accessory and anomalous vessels [2, 7, 8].
Modern 128-slice multidetector computed tomography (MDCT) scans are accurate in defining ASDs and PAPVR. ECG-gated MDCT enables a non-invasive and rapid image acquisition with high spatial and temporal resolution, optimized contrast bolus timing, and wide anatomic coverage. The presence, course, number of anomalous veins, and associated cardiovascular defects can be reliably observed by MDCT angiography [2, 8, 9, 10, 11].
The present series describes a group of adults with left-to-right shunts including PAPVR and/or ASD evaluated with ECG-gated 128-slice MDCT.
All patients were examined with TTE and/or TEE as a part of clinical evaluation. Furthermore, the presence of a left-to-right shunt was confirmed with a peripheral dye dilution technique. P/S ratio of more than 1. 5 was considered significant. Prospectively ECG-gated MDCT angiographies were performed with a 128-slice-scanner (Siemens, AS+). An imaging workstation (Siemens) was used for the interpretation of the volumetric datasets using transverse images complemented by multidimensional images as required.
In recent years modern MDCT and MRI techniques have gained increasing importance in the non-invasive assessment of vascular pathologies of the chest. In our patients, the diagnosis was established with certainty using contrast-enhanced ECG-gated chest MDCT with volume-rendered reconstructions. MDCT provided accurate information of pulmonary vein anatomy and cardiac shunts in patients with right ventricular enlargement.
The isotropic voxel size and good spatial resolution, as compared with other techniques, allow ex-amination of small vessels and shunts with multidimensional reconstructions using advanced workstations . However, there are some drawbacks for the routine use of MDCT . The radiation dose is a concern especially in young patients. However, using the newest technologies the radiation dose for a cardiac structure evaluation is as low as 1-5 mSv. Exposure can be reduced by ECG attenuation techniques that limit exposure during the less informative parts of the cardiac cycle. Gating remains problematic in patients with fast and irregular heart rates. The success of this method is therefore dependent on the correct use of pre-medication, ECG-gating, and special technical protocols. Data-processing of multidimensional images can be time consuming, but 2D- and 3D-images are valuable in the planning of surgery .
In some other studies, cardiac MRI has reliably detected and delineated sinus venosus defects and PAPVR. MRI offers several advantages over cardiovascular imaging. MRI does not use ionization radiation and does not necessarily require injection of a contrast medium [7, 12]. On the other hand, this method has lower spatial resolution, susceptibility artifacts, increased pixel size, and longer examination times than MDCT [9, 10]. In addition, known contraindications to MRI include claustrophobia, pacemakers and metal objects in the body area.
In our experience ECG-gated MDCT with fast data acquisition and multidimensional reconstructions offers excellent spatial resolution and the possibility to reliably depict intracardiac and pulmonary shunts.
Written informed consent was obtained from the patient for publication of this Case report and any accompanying images. All names and social security numbers have been removed from the images.
We would like to thank the technicians Ulla Nikupaavo and Matti Romppainen for their expertise in acquiring MDCT images.
- 2.Schertler T, Wildermuth S, Teodorovic N, Mayerc D, Marincek B, Boehma T: Visualization of congenital thoracic vascular anomalies using multi-detector row computed tomography and two- and three-dimensional post-processing. Eur J Radiol. 2007, 61: 97-119. 10.1016/j.ejrad.2006.08.015.CrossRefPubMedGoogle Scholar
- 4.Baim DS, Grossman W: Grossman's cardiac catheterization, angiography, and intervention. Detection of left-to-right intracardiac shunts. 2006, Philadelphia: Lippincot Williams & WilkinsGoogle Scholar
- 9.Cronin P, Kelly AM, Gross BH, Desjardins B, Patel S, Kazerooni EA, Carlos RC: Reliability of MDCT in characterizing pulmonary venous drainage, diameter and distance to first bifurcation: An Interobserver study. Acad Radiol. 2007, 14 (4): 437-44. 10.1016/j.acra.2007.01.023.CrossRefPubMedGoogle Scholar
- 10.Nicol ED, Kafka H, Stirrup J, Padley SP, Rubens MB, Kilner PJ, Gatzoulis MA: A single, comprehensive non-invasive cardiovascular assessment in pulmonary arterial hypertension: Combined computed tomography pulmonary and coronary angiography. Int J Card. 2009, 136 (3): 278-88. 10.1016/j.ijcard.2008.05.049.CrossRefGoogle Scholar
- 12.Ferrari VA, Scott CH, Holland GA, Axel L, Sutton M: Ultrafast three-dimensional contrast-enhanced magnetic resonance angiography and imaging in the diagnosis of partial anomalous pulmonary venous drainage. J Am Coll Cardiol. 2001, 37 (4): 1120-8. 10.1016/S0735-1097(01)01148-2.CrossRefPubMedGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.