J A C C : C A R D I O V A S C U L A R I M A G I N G VO L . 1 1 , N O . 7 , 2 0 1 8
ª 2 0 1 8 B Y T H E AM E R I C A N C O L L E G E O F C A R D I O L O G Y F O UN DA T I O N
P U B L I S H E D B Y E L S E V I E R
IMAGING VIGNETTE
Multimodality Cardiovascular Imaging ofUnroofed Coronary Sinus Defects
Bo Xu, MBBS (HONS),a Jorge Betancor, MD,a Paul C. Cremer, MD,a Rahul Renapurkar, MD,b Gosta B. Pettersson, MD,cCraig R. Asher, MD,d L. Leonardo Rodriguez, MDa
UNROOFED CORONARY SINUS (CS) DEFECTS ARE RARE ANOMALIES THAT RESULT FROM EMBRYOLOGIC
developmental abnormalities, leading to partial or complete absence of the common wall between the CS andthe left atrium. They account for less than 1% of atrial septal defects, having a strong association with apersistent left superior vena cava, and are often difficult to diagnose. Delayed diagnosis may lead to rightventricular enlargement and failure, and pulmonary hypertension. Here, we present the multimodalitycardiovascular imaging findings of unroofed CS defects (Figures 1 to 5). For simplicity, unroofed CS defects areclassified as types I, II, and III, referring to complete unroofing, partial unroofing of the mid-portion, and
A BLEFTARM
RIGHTARM
L
PR
A
C D
FIGURE 1 TTE and MDCT of a Patient With a Persistent LSVC
and Unroofed CS Defect
(A) Transthoracic echocardiography (TTE) (apical 4-chamber view)
demonstrating right-sided chamber enlargement. (B) After injec-
tion of agitated saline via the left arm, prominent contrast is seen in
the left heart with minimal opacification of right-sided chambers.
This confirms the presence of an unroofed coronary sinus (CS)
defect. (C) After injection of agitated saline via the right arm,
prominent contrast is seen in the right atrium and ventricle, with a
small amount of bubbles seen in the left-sided chambers. This
confirms the presence of a right-to-left intracardiac shunt.
However, this finding is not specific for unroofed CS defects. (D)
Note that the CS is not visualized in a true apical 4-chamber view, as
illustrated in this multidetector cardiac computed tomography
(MDCT) reconstruction, given the inferior and posterior location
of the CS. A ¼ anterior; L ¼ left; LSVC ¼ left superior vena cava;
P ¼ posterior; R ¼ right.
ISSN 1936-878X/$36.00 https://doi.org/10.1016/j.jcmg.2018.03.001
From the aSection of Cardiovascular Imaging, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio; bDepartment of
Diagnostic Radiology, Imaging Institute, Cleveland Clinic, Cleveland, Ohio; cDepartment of Thoracic and Cardiovascular
Surgery, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio; and the dDepartment of Cardiovascular Medicine,
Heart and Vascular Institute, Cleveland Clinic Florida, Weston, Florida. The authors have reported that they have no
relationships relevant to the contents of this paper to disclose. Drs. Xu and Betancor contributed equally to this work and are
joint first authors.
Manuscript received March 8, 2017; revised manuscript received February 5, 2018, accepted March 1, 2018.
FIGURE 2 TTE and MDCT of a Patient With a Persistent LSVC and Unroofed CS Defect
A
CS CS
CS
CSCS
RA
LA
LA
RUPV
RA
RV
-61cm/s
B C
D E F
(A) TTE (parasternal right ventricular [RV] inflow view), showing a dilated CS draining into the right atrium (RA). (B) TTE (parasternal RV inflow
view) with color Doppler imaging, showing flow from the dilated CS reaching the RA. (C)MDCT reconstruction of the RV inflow view. Note the
dilated CS draining into the RA, without a wall separating it from the left atrium (LA). Note the right upper pulmonary vein (RUPV) draining into
the LA, which communicates freely with the CS. (D) TTE (subcostal 4-chamber view) showing the communication between the atria. Note how
inferior the imaging plane must be in order to identify the defect in a 4-chamber view. (E) TTE (subcostal 4-chamber view with color Doppler
imaging) demonstrating communication between the atria. At the time of TTE imaging, a subcostal sweep in coronal and sagittal planeswill help
delineate the anatomyof the unroofed CS defect. (F)MDCT reconstruction of the subcostal short-axis view at the atrial/CS level, emphasizing the
inferior and posterior location of unroofed CS defects. This illustrates how easily unroofed CS defects can bemissed by TTE if dedicated off-axis
imaging planes are not acquired. It is important to note that unroofed CS defects are located posteriorly to the entrance of the inferior vena
cava into the RA, differentiating them from inferior sinus venosus atrial septal defects, on MDCT reconstruction. The double-headed arrow
highlights the unroofed coronary sinus, and the potential for interatrial shunting (either left-to-right, or right-to-left, depending on pressure
differences between the left atrium and right atrium). Abbreviations as Figure 1.
Xu et al. J A C C : C A R D I O V A S C U L A R I M A G I N G , V O L . 1 1 , N O . 7 , 2 0 1 8
Imaging of Unroofed Coronary Sinus Defects J U L Y 2 0 1 8 : 1 0 2 7 – 3 0
1028
partial unroofing of the terminal portion, respectively. Echocardiography is the first-line imaging modality,whereas multidetector cardiac computed tomography provides detailed anatomical information, whenechocardiography is not diagnostic. Cardiac magnetic resonance imaging is useful as an adjunct, particularlywhen quantification of intracardiac shunting is required (Figure 6).
A B
C D
CS
CS
LA
LA
LAA
Aorta
FIGURE 3 TTE and MDCT of a Patient With a Persistent LSVC and
Unroofed CS Defect
(A) TTE (apical 2-chamber view) of a patient with an unroofed CS
defect and a persistent LSVC. Note the dilated CS freely communi-
cating with the LA without a separating membrane. (B) MDCT recon-
struction of the apical 2-chamber view shown in Figure 3A, showing
the unroofed CS just posterior to the LA, confirming the absence of a
membrane separating the CS from the LA. (C) TTE (apical 3-chamber
view) in a patient with an unroofed CS and a persistent LSVC. Note that
the CS is not well visualized in the apical 3-chamber view (white arrow).
(D) MDCT reconstruction of the 3-chamber view shown in
Figure 3C, demonstrating why the CS is poorly visualized in this view,
given that it lies perpendicular to the cross-sectional imaging plane
(white arrow). LAA ¼ left atrial appendage; other abbreviations as in
Figures 1 and 2.
H
A
RA
RV
JPEG
LA
B C
FIGURE 4 TEE and MDCT of a Patient With a Type III
Unroofed CS Defect and an Absent LSVC
(A) Transesophageal echocardiography (TEE) (lower
esophageal view at the gastroesophageal junction; 0�),
showing a type III unroofed CS defect. Note the partial
absence of CS wall (arrow, dashed line), which allows
communication between the right and left atria. (B)
MDCT showing a type III unroofed CS defect. This is the
optimal CS MDCT reconstruction to identify the presence,
as well as the location and extent of a CS defect
(dashed white line and black arrows). Note the similar
contrast intensities within the LA and CS, due to the
absent wall in the terminal portion of the CS. Note the
well-demarcated margin separating the LA from the CS
in its proximal to mid-portion. (C) Pseudo-2-chamber
MDCT reconstruction, showing a type III unroofed CS
defect with absent wall in the terminal portion of the CS
(black arrow), which allows communication with the
LA. Note the similar contrast intensities within the LA
and CS. It is also important to note that to demon-
strate the posterior location of the unroofed CS defect,
modified coronal and oblique sagittal MDCT pro-
jections are used. Abbreviations as in Figures 1 and 2.
J A C C : C A R D I O V A S C U L A R I M A G I N G , V O L . 1 1 , N O . 7 , 2 0 1 8 Xu et al.J U L Y 2 0 1 8 : 1 0 2 7 – 3 0 Imaging of Unroofed Coronary Sinus Defects
1029
LA
CS
CS
RA
CS
JPEG
A B
C D
FIGURE 5 TEE and MDCT of a Patient With a Type II Unroofed CS Defect
and Absent LSVC
(A) TEE (lower esophageal view at the gastroesophageal junction; 0�)
showinga type II unroofedCSdefectwithpartial absence of tissue in themid-
portion of the CSwall (arrow, dashed line), allowing communication with LA.
Note the normal wall at the terminal portion of the CS. (B)MDCT recon-
struction in a patient with a type II unroofed CS defect. Contrast opacifi-
cation in the CS is similar to that in the left ventricle. The CS appears to drain
normally into theRA,withaverywelldemarcatedwall around it; however, this
reconstructiondoesnothelpelucidate thepresenceofanunroofedCS, as the
defect will always be adjacent to the LA, which is not seen in this recon-
struction. (C) Pseudo-2-chamber MDCT reconstruction, demonstrating a
type II unroofedCSdefectwith absentwall in themid-portion of the CS (black
arrow), allowing communicationwith theLA. Contrastopacification in theCS
is similar to that in the left ventricle. This reconstruction allows identifica-
tion of type II unroofed CS defects (mid-portion). However, a type III CS
defect (terminalportion)couldbemissed,unless it is sufficiently large. (D)This
is theoptimalCSMDCT reconstruction to identify thepresence, aswell as the
location and extent of a CS defect (black arrow). Note the similar contrast
intensitieswithin theLAandCS, due to the absentwall in themid-portionof
the CS; however, there is a well demarcatedmargin separating the LA from
theCS in its terminalportion. It is also important tonote that todemonstrate
the posterior location of the unroofed CS defect, modified coronal and
oblique sagittal MDCT projections are used. Abbreviations as in
Figures 1, 2, and 4.
CS CS
LA LA
LVRA
A B FIGURE 6 CMR Imaging of a Patient
With a Type I Unroofed CS Defect and a
Persistent LSVC
(A) Steady-state free precession
sequence demonstrating a basal slice
of the left ventricular (LV) short-axis
stack. Note that this view is similar to
the MDCT reconstructions shown in
Figure 4, all of which allow for an
excellent display of the different types
of unroofed CS defects. The dashed
line demarcates the totally absent
tissue between the LA and the CS
(arrow). (B) Two-chamber reconstruc-
tion showing a type I unroofed CS
defect with totally absent wall be-
tween the CS and the LA (arrow).
Compare with echocardiographic and
MDCT assessment of unroofed CS
defects in Figures 1 to 5. CMR ¼cardiac magnetic resonance; other
abbreviations as in Figures 1 and 2.
Xu et al. J A C C : C A R D I O V A S C U L A R I M A G I N G , V O L . 1 1 , N O . 7 , 2 0 1 8
Imaging of Unroofed Coronary Sinus Defects J U L Y 2 0 1 8 : 1 0 2 7 – 3 0
1030
ADDRESS FOR CORRESPONDENCE: Dr. Bo Xu, Section of Cardiovascular Imaging, Heart and VascularInstitute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195. E-mail: [email protected].
KEY WORDS cardiac magnetic resonance imaging, echocardiography, multidetector cardiac computed tomography, multimodality imaging,unroofed coronary sinus