Use of cardiovascular magnetic resonance in the evaluation of a giant right atrial appendage aneurysm: a case report and review of the literature
Sivakumaran et al. BMC Res Notes
Use of cardiovascular magnetic resonance in the evaluation of a giant right atrial appendage aneurysm: a case report and review of the literature
Lojan Sivakumaran 0 1 2
Karl Sayegh 0
Emile Mehanna 0
Frank W. Sanchez 3
Jonathan Fields 3
Ricardo Cury 3
0 McGill University Health Centre , 1650 Cedar Ave, Montreal, QC H3G 1A4 , Canada
1 Centre de recherche du Centre hospitalier de l'Université de Montréal , 900 St Denis, Montreal, QC H2X 0A9 , Canada
2 Université de Montréal , 2900 Boulevard Edouard-Montpetit, Montreal, QC H3T 1J4 , Canada
3 Miami Cardiac and Vascular Institute Baptist Hospital of Miami , 8900 N Kendall Drive, Miami, FL 33176 , USA
Background: Right atrial appendage aneurysms are rare entities that may have significant clinical consequences. When co-existing with atrial fibrillation, patients are at risk of developing pulmonary or paradoxical systemic emboli. Case presentation: An elderly patient presented to medical attention with symptoms of acute diverticulitis. On abdominal computed tomography, a massively enlarged right atrial appendage aneurysm was discovered incidentally. The aneurysm caused marked compression of the right ventricle and contained an area of hypoenhancement concerning for an intraluminal thrombus. Gadolinium-enhanced cardiovascular magnetic resonance was performed and first-pass perfusion images demonstrated that the area of hypoenhancement was in fact poorly mixing blood. The patient was therefore managed medically. Conclusion: Right atrial appendage aneurysms are infrequently encountered cardiac abnormalities. In the literature, surgery has been offered to patients who are young, symptomatic, or have evidence of thrombotic disease, although whether this practice pattern is associated with superior clinical outcomes is unclear. In the present case, gadoliniumenhanced cardiovascular magnetic resonance imaging was used to exclude the presence of intraluminal thrombus in an elderly patient, which helped orient the patient's treating team towards medical-rather than surgical-therapy.
Right atrial appendage aneurysm; Cardiovascular magnetic resonance (CMR); Thrombus; Congenital heart anomaly
Right atrial appendage (RAA) aneurysms are abnormal
dilatations of the RAA that are associated with
dysplasia and fibrosis of the atrial tissue [
]. They are rarely
reported in the literature and are less frequently
encountered compared to other cardiac aneurysms . A
literature review published in 2014 found that the highest
prevalence of RAA aneurysms was in the third
decade of life, with cases noted from the perinatal period
to 72 years of age [
]. Since this review was published,
however, there have been several additional pediatric
cases reported [
RAA aneurysms are typically asymptomatic and are
often discovered incidentally. The most common
clinical findings in patients with symptomatic RAA
aneurysms are persistent atrial tachyarrhythmia [
and dyspnea [
]. Less frequently encountered findings
are outlined in Table 1. While RAA aneurysms have been
found in patients with atrial septal defects [
7, 10, 12, 13,
], ventricular septal defects, spontaneous
], left atrial appendage aneurysms, and
tricuspid/mitral regurgitation [
], there is currently no clear
etiological relationship between RAA aneurysms and
As RAA aneurysms are often diagnosed in the
context of atrial fibrillation, the development of intraluminal
thrombosis and subsequent pulmonary or paradoxical
systemic embolism is of concern [
formation is as an indication in the literature for surgical
resection of RAA aneurysms [
]. However, the
differentiation of an intraluminal thrombus from flow
stasis is not always straightforward, especially when using
echocardiography and contrast-enhanced computed
tomography (CT) alone. We therefore present the use of
cardiovascular magnetic resonance (CMR) to
characterize a massive intraluminal hypodensity/filling defect in a
patient with a RAA aneurysm found on CT.
An elderly patient between 50–70 years of age (details
obscured to protect patient privacy) presented to
medical attention with increasing left lower quadrant pain and
nausea over 3 days. Relevant past medical history was
significant for atrial fibrillation, diabetes mellitus, and
hypertension. Family history, medications, and allergies
Contrast-enhanced abdominal CT showed active
sigmoid diverticulitis. The patient was put on bowel rest
and was treated with intravenous hydration and
antibiotics. Incidentally, on the superior aspect of the scan
field, a massively enlarged RAA (10.0 × 6.0 cm) was
noted causing marked mass effect on the right
ventricle (RV) (Fig. 1). A large region of hypoenhancement
(7.6 × 3.0 cm) was also identified at the tip of the RAA.
Given the patient’s history of arrhythmia, the treating
team was concerned about the presence of an
A cardiology consult was obtained and the patient was
sent for echocardiography. Echocardiography similarly
revealed an enlarged RAA that compressed the RV and
contained an echogenic density at its tip. Right
ventricular systolic pressure was 24 mmHg and the right
ventricular inner diameter was mildly elevated at 3.6 cm. Doppler
showed mild tricuspid and pulmonary valve insufficiency
with normal flow rates. A normal left ventricular ejection
fraction (55%) with concentric left ventricular
hypertrophy was observed.
Cardiovascular magnetic resonance (CMR) (1.5 T,
Philips Ingenia Imaging System®, Philips Healthcare®)
imaging was subsequently performed. Balanced turbo
field-echo (BTFE) short axis (sax) showed aneurysmal
dilation of the RAA measuring 10.5 × 7.5 × 5.5 cm with
a wide ostium of 3.6 × 3.6 cm. There was a lack of
contractility of the aneurysm noted and evidence of
significant compression of the right ventricular free wall during
the cardiac cycle (see Fig. 2 or Additional file 1).
Assessment of left and right global systolic functions using
Simpson’s method in the short axis orientation revealed
a normal left ventricular ejection fraction of 62% and a
normal right ventricular ejection fraction of 57%.
Multiple CMR sequences showed a difference in signal
between the blood pool contained within the RAA and
the rest of the cardiac chambers (Fig. 3). Balanced fast
field echo using SENSE technique (sB-FFE) showed that
the contents of the RAA aneurysm was of lower signal
intensity than the bright blood signal in the ventricles.
T1-spin echo (T1-SE) images obtained without fat
saturation demonstrated that the contents of the RAA
aneurysm were of intermediate signal intensity as opposed to
the dark blood signal in the RV. The signal intensity did
not change with fat saturation. T2-weighted short-tau
inversion relaxation (STIR) showed high signal intensity
in the RAA in contrast to the dark blood pool in the
ventricles. Finally, post-contrast sax images showed that the
signal in RAA aneurysm was similar to that of the
ventricular blood pools.
First-pass perfusion axial images were obtained
following the administration of 25 mL of IV gadolinium
contrast agent (Multihance®) (Additional file 2 and Fig. 4).
The cine showed progressive mixing of the RAA
aneurysm contents with contrast material until complete
opacification. The signal abnormality on CT,
echocardiography, and CMR was therefore concluded to have
been caused by slow-mixing blood. Given the patient’s
advanced age and the lack thrombotic disease, the patient
was managed medically with anticoagulation.
RAA aneurysms are rare clinical entities. In the present
case, gadolinium-enhanced CMR was used to exclude
an aneurysmal thrombosis and orient the treating team
towards medical management. To the best of the authors’
knowledge, this is first published case where CMR was
used to direct therapy in such a context.
Echocardiography is the initial investigation of choice
in the workup of cardiac abnormalities. It is inexpensive,
widely available and minimally invasive.
Echocardiography plays a particularly important role in the pediatric
population, where the radiation exposure of CT scans
and the long scan times of CMR are of particular concern
]. Indeed, agitated saline echocardiography has been
used to differentiate RAA aneurysms from pericardial
effusions in the neonate [
] and fetal ultrasound has been
used to detect RAA aneurysms in the prenatal period [
]. Compared to CT and CMR, however,
echocardiography has a poorer ability to differentiate RAA
aneurysms from similarly-appearing anomalies [
] such as
pericardial cysts [
], Ebstein’s anomaly [
], epicardial and pericardial fat lesions, and
CT and CMR are both highly specific for the detection
of RAA aneurysms [
]. CT offers the benefit of a faster
capture time, but it exposes patients to ionizing
radiation and nephrotoxic contrast agents. Filling defects can
be assessed on CT with delayed phase scanning 1–2 min
after contrast administration, but this study is difficult to
protocol in advance unless the operator is already aware
of the defect.
CMR offers superior anatomical resolution and the
ability to observe delayed blood mixing over time with
cine imaging. CMR also has the ability to evaluate the
function of the RV and to observe any mass effect exerted
on the heart during the cardiac cycle. Presently, the use
of CMR to assess RAA aneurysms in the literature has
been limited; CMR was used in only 8 of 22 published
English-language case reports (see Table 2 for a summary
of published findings). This is likely due to the relatively
recent emergence of the technology and its limited
availability. Regardless, CMR can be invaluable in
characterizing such cardiac abnormalities.
In present case, the treating team opted to pursue
medical management once the area of hypoenhancement
within the RAA aneurysm was characterized as slow flow
by CMR. This conservative approach has been supported
in the literature for patients who are asymptomatic and
1, 6, 8
]. Conversely, in patients who are younger,
symptomatic, or who have evidence of thrombosis,
surgical excision appears to be the preferred therapy [
]; a Cox-maze procedure may also be performed
to treat concomitant arrhythmias [
]. The rarity of
RAA aneurysms makes it difficult to determine whether
such an intervention confers a survival benefit, however
The interaction of RAA aneurysms with other
comorbidities merits mention. The patient in the present case
also suffered from diverticulitis, a condition which may
be treated medically or surgically. Such a scenario calls
into question how other diseases should be managed
in the context of RAA aneurysms, especially those that
require surgery. Unfortunately, there is a paucity of data
available in the literature to guide clinicians. The
presence of a RAA aneurysm in and of itself does not appear
to be a contraindication to surgery. However, if the
aneurysm is large enough to affect cardiac output, contribute
to outflow tract obstruction, or cause valvular
], then these comorbidities must be taken into
consideration. For example, if the patient is preload
dependent due to the impairment of ventricular function,
this should be considered in the patient’s perioperative
fluid management. If the patient presents in heart failure,
inotropes and a monitored setting should be considered
to maintain adequate post-operative tissue perfusion.
In the present case, given the patient’s preserved
biventricular function and minimal regurgitation, few
perioperative modifications would have been necessary. A
pre-operative medical consultation would nonetheless
have been recommended.
In conclusion, we present the use of CMR to
characterize a giant RAA aneurysm containing an area of
hypoenhancement on CT that was concerning for a massive
thrombus. Multiplanar, multisequential
gadoliniumenhanced CMR—including first-pass perfusion cine
imaging—was used to characterize this area as slow flow
and the patient was managed medically. Despite the
rarity of this condition, future studies should be directed
towards determining whether surgical management is of
benefit compared to medical management.
Additional file 1. Balanced turbo field-echo cine in short axis view. The
size and position of the right atrial appendage aneurysm is shown in
relation to the right ventricle. Note how the right atrial appendage aneurysm
compresses and deforms the right ventricle throughout the cardiac cycle.
Additional file 2. First pass perfusion cine of the right atrial appendage
aneurysm in axial plane following the administration of IV gadolinium.
Following the administration of 25 mL of IV gadolinium contrast agent
(Multihance®), there is progressive and complete enhancement of the
RAA aneurysm. This indicates that the area of hypoenhancement found
on contrast-enhanced computed tomography was slow-flowing blood,
rather than a thrombus.
AMB: acute marginal branch; BTFE: balanced turbo field-echo; CMR: cardiac
magnetic resonance; CT: computed tomography; LA: left atrium; LV: left
ventricle; LVEF: left ventricular ejection fraction; MRI: magnetic resonance imaging;
O: ostium; RA: right atrium; RAA: right atrial appendage; RCA: right coronary
artery; RV: right ventricle; sax: short axis; SB-FFE: balanced fast field echo using
SENSE technique; STIR: short-tau inversion recovery; T1-SE: T1 spin echo.
LS contributed to manuscript preparation and revision. KS participated in
case selection, preparation of CT and CMR images, and manuscript revision.
EM participated in manuscript preparation and revision. FS, JF, and RC
contributed to case selection, figure preparation, and manuscript revision. All authors
take responsibility for their contributions. All authors read and approved the
The authors declare that they have no competing interests.
Availability of data and materials
Consent for publication
The authors were unfortunately unable to contact the patient to obtain
consent for publication of this case report despite numerous attempts (as
verified by author KS). All scans have been anonymized and no clinical images
(i.e. non-radiological) have been included. Only minimal patient data has been
included to protect patient privacy.
Ethics approval and consent to participate
No funding was received for the draft of this manuscript.
Springer Nature remains neutral with regard to jurisdictional claims in
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