1. The “Broken Ring” Sign in Magnetic Resonance Imaging of Partial Anomalous Pulmonary Venous Connection to the Superior Vena Cava 
PAUL R. JULSRUD, M.D., RICHARD L. EHMAN, M.D. 
Mayo Clinic Proceedings 
Volume 60, Issue 12, Pages (December 1985)
DOI: /S (12)
Copyright © 1985 Mayo Foundation for Medical Education and Research Terms and Conditions

2. Fig. 1
(case 1). Angiogram in 30° right anterior oblique projection. Note transvenous catheter in superior vena cava, with its tip in the anomalously connected right upper pulmonary vein.
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3. Fig. 2
A, Transverse spin echo magnetic resonance image of normal anatomy at level of right pulmonary artery. Arrow points to lateral wall of superior vena caval “ring.” B, Diagram of structures demonstrated in A. A = ascending aorta; D = descending aorta; MPA = main pulmonary artery; RPA = right pulmonary artery; S = superior vena cava.
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Copyright © 1985 Mayo Foundation for Medical Education and Research Terms and Conditions

4. Fig. 3
Transverse spin echo magnetic resonance image, demonstrating normal posterior break in superior vena caval “ring” due to entrance of azygos vein. Longer arrow indicates the arch of azygos vein, and shorter arrow indicates ascending azygos vein. Note intimal flap in descending aorta in this image of a patient with aortic dissection.
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5. Fig. 4
Coronal spin echo magnetic resonance image in plane of the junction of the superior vena cava and the right atrium, demonstrating uninterrupted lateral wall of superior vena cava (arrow). Note absence of tricuspid valve in this image of patient with tricuspid atresia. RA = right atrium; RV = right ventricle.
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6. Fig. 5
(case 1). A, Transverse spin echo magnetic resonance image at level of carina, demonstrating break in lateral aspect of superior vena caval “ring” (arrow) and pronounced dilatation of superior vena cava. B, Coronal spin echo magnetic resonance image in plane of superior vena cava (S). Note “break” in lateral wall of superior vena cava at point of anomalous pulmonary venous connection (arrow). PA = pulmonary artery.
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Copyright © 1985 Mayo Foundation for Medical Education and Research Terms and Conditions

7. Fig. 6
(case 1). Transverse spin echo magnetic resonance images, which proceed caudally from transverse slice shown in Figure 5 A. A, Transverse section below entrance of anomalously connecting pulmonary vein, demonstrating dilated superior vena cava (S) with intact “ring.” B, Transverse section at level of aortic valve (A), demonstrating dilated right and left atria in conjunction with an intact superior portion of interatrial septum (arrow). LA = left atrium; RA = right atrium.
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8. Fig. 7
(case 1). Coronal spin echo magnetic resonance images. A, In plane of anomalously connected pulmonary vein (arrow). B, In plane 1 cm posterior to image in A, demonstrating intact interatrial septum. Note dilatation of both atria and enlarged coronary sinus immediately inferior to interatrial septum.
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Copyright © 1985 Mayo Foundation for Medical Education and Research Terms and Conditions

9. Fig. 8
(case 2). Angiogram obtained by means of a transvenous catheter in superior vena cava with its tip positioned in anomalously connecting right upper pulmonary vein (RPV), with use of a compound angulated view (70° left anterior oblique and 20° caudocranial). Note right-to-left shunting of contrast material, which substantiates sinus venosus atrial septal defect (arrow). LA = left atrium; RA = right atrium; S = superior vena cava.
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10. Fig. 9
(case 2). Transverse spin echo magnetic resonance images with motion artifact caused by tremor in patient with Parkinson's disease. A, Plane of image above level of entrance of anomalous pulmonary venous connection, demonstrating normal complete superior vena caval “ring.” (See Figures 2 A and B for comparison.) B, Plane of image at level of entrance of anomalous pulmonary venous connection. Note break in lateral aspect of superior vena caval “ring” (arrow). C, Plane of image immediately inferior to the junction of the superior vena cava and right atrium, demonstrating interruption in interatrial septum due to sinus venosus atrial septal defect in superoposterior aspect of interatrial septum. Arrow indicates edge of interatrial septum adjacent to sinus venosus atrial septal defect. (See Figure 6 B for comparison.)
Mayo Clinic Proceedings  , DOI: ( /S (12) )
Copyright © 1985 Mayo Foundation for Medical Education and Research Terms and Conditions