Flow-sensitive four-dimensional magnetic resonance imaging facilitates and improves the accurate diagnosis of partial anomalous pulmonary venous drainage

Clinical Significance of Partial Anomalous Pulmonary Venous Connections (Isolated and Atrial Septal Defect Associated) Determined by Cardiovascular Magnetic Resonance

BACKGROUND

Partial anomalous venous connections (PAPVC) are associated with left to right shunting and right heart dilatation. Identification of PAPVC has increased with widespread use of cross-sectional imaging modalities. However, management strategies are mostly based on expert opinion given the scarcity of data from large series. We aimed to define types and significance of isolated and atrial septal defect (ASD) associated PAPVC detected by cardiovascular magnetic resonance.

METHODS

We retrospectively reviewed our cardiovascular magnetic resonance database from 2002 to 2018 to identify isolated or ASD-associated PAPVC cases.

RESULTS

A total of 215 patients (median age 46 years; range, 6-83) with isolated or ASD-associated PAPVC were identified among 102 135 clinical cardiovascular magnetic resonance studies. Of these, 104 were isolated and 111 were associated with an ASD. Anomalous connection of right upper pulmonary vein was the most common single venous anomaly (99/215), but in the isolated PAPVC group there were more anomalous left than right upper pulmonary veins (39 versus 34). The Qp/Qs was significantly higher for isolated anomalous single right upper pulmonary vein than left upper pulmonary vein (1.6 versus 1.4 respectively; P=0.01) as were right ventricular end-diastolic volumes (113.7±30.9 versus 90 [57-157] mL/m2, P=0.004). In the PAPVC with an ASD group, sinus venosus ASDs (82%) were associated with right-sided PAPVCs while both right and left-sided venous anomalies were seen in secundum ASDs (18%). In a substantial number of patients (30 out of 91) with sinus venosus ASDs, PAPVCs were more complex and involved more than a single anomalous right upper pulmonary vein; and in 5 patients with ASD, PAPVC was identified only after the ASD closure.

CONCLUSIONS

This large series provides descriptive and hemodynamic features for isolated and ASD-associated PAPVCs. Anomalous isolated right upper pulmonary vein may cause a significant shunt (Qp/Qs >1.5). PAPVC associated with sinus venosus and secundum ASDs might be more complex than a single anomalous pulmonary vein and missed before ASD correction.

4D flow MRI applications in congenital heart disease

Advances in the diagnosis and management of congenital heart disease (CHD) have resulted in a growing population of patients surviving well into adulthood and requiring lifelong follow-up. Flow quantification is a central component in the assessment of patients with CHD. 4D flow magnetic resonance imaging (MRI) has emerged as a tool that enables comprehensive study of flow. It involves the acquisition of a three-dimensional time-resolved volume with velocity encoding in all three spatial directions along the cardiac cycle. This allows flow quantification and visualization of blood flow patterns as well as the study of advanced hemodynamic parameters as kinetic energy and wall shear stress. 4D flow MRI-based study of flow has given insight into the altered hemodynamics in CHD particularly in bicuspid aortic valve disease and Fontan circulation. The aim of this review is to discuss the expanding clinical and research applications of 4D flow MRI in CHD as well its limitations.Key Points• Three-dimensional velocity encoding allows not only flow quantification but also the visualization of multidirectional flow patterns and the study of advanced hemodynamic parameters.• 4D flow MRI has added insight into the abnormal hemodynamics involved in congenital heart disease in particular in bicuspid aortic valve and Fontan circulation.• The main limitation of 4D flow MRI in congenital heart disease is the relatively long scan duration required for the complete coverage of the heart and great vessels with adequate spatiotemporal resolution.

Diagnosis and treatment of adults with congenital heart disease

Approximately 50 million adults worldwide have known congenital heart disease (CHD). Among the most common types of CHD defects in adults are atrial septal defects and ventricular septal defects followed by complex congenital heart lesions such as tetralogy of Fallot. Adults with CHDs are more likely to have hypertension, cerebral vascular disease, diabetes and chronic kidney disease than age-matched controls without CHD. Moreover, by the age of 50, adults with CHD are at a greater than 10% risk of experiencing cardiac dysrhythmias and approximately 4% experience sudden death. Consequently, adults with CHD require healthcare that is two- to four-times greater than adults without CHD. This paper discusses the diagnosis and treatment of adults with atrial septal defects, ventricular septal defects and tetralogy of Fallot.

Low-Dose Computed Tomographic Imaging of Partial Anomalous Pulmonary Venous Connection in Children

Background:

In this study, we aimed to determine lobar distribution, drainage sites, and associated cardiovascular anomalies of partial anomalous pulmonary venous connection in pediatric patients using low-dose multidetector computed tomographic angiography.

Methods:

Sixty-one cases (27 female, mean age: 4.7 years) with partial anomalous pulmonary venous connection diagnosed by multidetector computed tomographic angiography were included in this study. In all patients, multidetector computed tomographic angiography examinations were performed using dual-source 256-slice scanner without sedation.

Results:

In 61 patients, 73 anomalous pulmonary veins were detected, 56 (77%) of them were right-sided and 17 (23%) were left-sided. Of 56 right-sided anomalous pulmonary veins in 49 patients, 38 (68%) drained into superior vena cava, eight (14%) into atriocaval junction, six (11%) into inferior vena cava, three (5%) into right atrium, and one (2%) into levoatriocardinal vein. Of 17 left-sided anomalous pulmonary veins in 12 patients, 16 (94%) drained into left innominate vein, and one (6%) into coronary sinus. Only seven (12%) patients had isolated partial anomalous pulmonary venous connection, whereas 54 (88%) patients had additional cardiovascular anomalies. The most common (66%) associated anomaly is atrial septal defect. The overall mean effective radiation dose was 1.12 mSv (range: 0.15-7.41 mSv), and it was 0.58 mSv (range: 0.15-0.73) in the patients younger than one-year old.

Conclusions:

The presence and course of the anomalous pulmonary veins and associated cardiovascular anomalies can be reliably detected by dual-source 256-slice multidetector computed tomographic angiography with low radiation doses.

Total Anomalous Pulmonary Venous Connection in Children: Preoperative Evaluation with Low-Dose Multidetector Computed Tomographic Angiography

We report the results of our retrospective evaluation, from February 2011 through August 2014, of the anatomic features of total anomalous pulmonary venous connection (TAPVC) and its associated cardiovascular anomalies in a pediatric population. In all 43 patients under study (23 female; average age, 9 mo [range, 4 d-7.1 yr]), these examinations had been performed with a dual-source 256-detector scanner. The type of TAPVC, the presence of obstruction, and the association with other cardiovascular anomalies were investigated and recorded. In accordance with the absence or presence of these accompanying anomalies, patients were subdivided into 2 groups: isolated and complex. In the 43 patients, 22 (51%) TAPVCs were supracardiac, 10 (23%) were cardiac, 6 (14%) were infracardiac, and 5 (12%) were mixed. Obstruction was detected in 7 patients. Seventeen patients were in the isolated group and 26 in the complex group. The diagnostic agreements between multidetector computed tomographic angiographic and surgical results were 100% in both the isolated and complex groups. The overall average effective radiation dose was 0.66 mSv (range, 0.15-1.11 mSv); and it was 0.52 mSv (range, 0.12-0.72 mSv) in patients younger than 1 year of age. We conclude that computed tomographic angiography with a dual-source 256-slice multidetector scanner is a reliable imaging method that enables, despite lower radiation doses, the detailed and comprehensive anatomic imaging of TAPVC in neonates and children.

Flow-sensitive four-dimensional velocity-encoded magnetic resonance imaging reveals abnormal blood flow patterns in the aorta and pulmonary trunk of patients with transposition

BACKGROUND AND OBJECTIVES

Flow profiles are important determinants of fluid-vessel wall interactions. The aim of this study was to assess blood flow profiles in the aorta and pulmonary trunk in patients with transposition and different ventriculoarterial connection, and hence different mechanics of the coherent pump.

METHODS

In all, 29 patients with operated transposition--concordant atrioventricular and discordant ventriculoarterial connection, and no other cardiac malformation--and eight healthy volunteers were assessed with cardiac magnetic resonance imaging: n = 17 patients after atrial redirection, with a morphologic right ventricle acting as systemic pump and a morphologic left ventricle connected to the pulmonary trunk, and n = 12 patients after the arterial switch procedure, with physiologic ventriculoarterial connections. Flow-sensitive four-dimensional velocity-encoded magnetic resonance imaging was used to analyse systolic flow patterns in the aorta and pulmonary trunk, relating to helical flow and vortex formation.

RESULTS

In the aorta, overall helicity was present in healthy volunteers, but it was absent in all patients independent on the operation technique. Partial helices were observed in the ascending aorta of 58% of patients after arterial switch. In the pulmonary trunk, mostly parallel flow was seen in healthy volunteers and in patients after arterial switch, whereas vortex formation was present in 88% of patients after atrial redirection.

CONCLUSION

Blood flow patterns differ substantially between the groups. In addition to varying mechanics of the coherent pumping ventricles, the absent overall helicity in all patients might be explained by the missing looping of the aorta in transposition.

Feasibility of 4D flow MR imaging of the brain with either Cartesian y-z radial sampling or k-t SENSE: comparison with 4D Flow MR imaging using SENSE

PURPOSE

A drawback of time-resolved 3-dimensional phase contrast magnetic resonance (4D Flow MR) imaging is its lengthy scan time for clinical application in the brain. We assessed the feasibility for flow measurement and visualization of 4D Flow MR imaging using Cartesian y-z radial sampling and that using k-t sensitivity encoding (k-t SENSE) by comparison with the standard scan using SENSE.

MATERIALS AND METHODS

Sixteen volunteers underwent 3 types of 4D Flow MR imaging of the brain using a 3.0-tesla scanner. As the standard scan, 4D Flow MR imaging with SENSE was performed first and then followed by 2 types of acceleration scan-with Cartesian y-z radial sampling and with k-t SENSE. We measured peak systolic velocity (PSV) and blood flow volume (BFV) in 9 arteries, and the percentage of particles arriving from the emitter plane at the target plane in 3 arteries, visually graded image quality in 9 arteries, and compared these quantitative and visual data between the standard scan and each acceleration scan.

RESULTS

4D Flow MR imaging examinations were completed in all but one volunteer, who did not undergo the last examination because of headache. Each acceleration scan reduced scan time by 50% compared with the standard scan. The k-t SENSE imaging underestimated PSV and BFV (P < 0.05). There were significant correlations for PSV and BFV between the standard scan and each acceleration scan (P < 0.01). The percentage of particles reaching the target plane did not differ between the standard scan and each acceleration scan. For visual assessment, y-z radial sampling deteriorated the image quality of the 3 arteries.

CONCLUSION

Cartesian y-z radial sampling is feasible for measuring flow, and k-t SENSE offers sufficient flow visualization; both allow acquisition of 4D Flow MR imaging with shorter scan time.