CASE-IN-POINT

MR findings of a rare defect, coronary sinus ASD

Abhishek Chaturvedi • Theodore J. Dubinsky •

Jeffrey H. Maki

Received: 16 June 2010 / Accepted: 2 July 2010 / Published online: 17 July 2010

� Springer Science+Business Media, B.V. 2010

Abstract The coronary sinus drains the cardiac

veins into the right atrium. An unroofed coronary

sinus is the least common type of atrial septal defect

(\1%). An unroofed coronary sinus also communi-

cates with the left atrium, in addition to its normal

communication with the right atrium. This defect is

difficult to diagnose. MR provides accurate anatomic

details about the location and size of defect. Phase

contrast velocity-encoded MR also helps towards

quantifying the shunt volume. This case represents

classical findings of this rare defect. Our patient first

presented in the 8th decade with features of right

heart failure.

Keywords Atrial septal defect � Cardiac MRI �Coronary sinus

A 76-year-old male presented with right heart failure.

Saline contrast echocardiography demonstrated a

right to left shunt suspicious for atrial septal defect

(ASD). MR was requested to better define the defect.

Bright blood cine short axis MR images depicted a

dilated coronary sinus communicating with the left

atrium (Fig. 1a). Axial images demonstrated the

normal opening of the coronary sinus in right atrium

(Fig. 1b). Contrast-enhanced MR confirmed the

defect (Fig. 1c). By phase contrast MR, pulmonic to

systemic flow ratio (Qp: Qs) was 1.5. In addition,

there was a small pericardial effusion, moderate

tricuspid regurgitation & right atrial enlargement.

IVC & hepatic veins were also dilated. Phase contrast

MR measured the defect as 18 9 12 mm with a shunt

volume of 21 cc (Fig. 1d).

Coronary sinus ASD is the rarest type of ASD, and

consists of focal or complete absence of coronary

sinus roof, resulting in communication with left

atrium. It is classified as [1]: Type I, completely

unroofed with persistent left superior vena cava

(LSVC); type II, completely unroofed without LSVC;

type III, partially unroofed mid portion; and type IV,

partially unroofed terminal portion (as in this case).

These patients can present with brain abscess or

embolic events from right-to-left shunt [2].

Most cases of coronary sinus ASD are diagnosed

in young adulthood. This case was first diagnosed in

the 8th decade. MR is useful to evaluate posterior

cardiac structures which are difficult to visualize on

transthoracic echocardiography. By phase contrast

MR, size of the defect and shunt volume can be

calculated. The patient underwent successful pericar-

dial patch closure of ASD with tricuspid valve

annuloplasty.

A. Chaturvedi (&) � T. J. Dubinsky � J. H. Maki

Department of Radiology, University of Washington,

357115, Seattle, WA 98195, USA

e-mail: abhic@uw.edu

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Int J Cardiovasc Imaging (2012) 28:429–430

DOI 10.1007/s10554-010-9670-8

References

1. Ootaki Y, Yamaguchi M, Yoshimura N, Oka S, Yoshida M,

Hasegawa T (2003) Unroofed coronary sinus syndrome:

diagnosis, classification, and surgical treatment. J Thorac

Cardiovasc Surg 126(5):1655–1656. doi:10.1016/S0022522

303010195

2. Hahm JK, Park YW, Lee JK, Choi JY, Sul JH, Lee SK, Cho

BK, Choe KO (2000) Magnetic resonance imaging of

unroofed coronary sinus: three cases. Pediatr Cardiol

21(4):382–387. doi:10.1007/s002460010087

Fig. 1 Steady state free precession CMR images at base in

short axis plane (a) demonstrating communication of coronary

sinus (CS—arrowheads) with the left atrium (LA). Axial

images (b) show the dilated CS draining into the right atrium

(RA). Maximum intensity projection coronal reformatted

images from the contrast enhanced venous phase MRA

(c) confirm the communication between the LA and CS (whitearrow). 21 cc of flow was present from the LA to CS (whitearrow) by en face phase contrast MR (d). RV = right ventricle

430 Int J Cardiovasc Imaging (2012) 28:429–430

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