DOI:10.2214/AJR.07.2035
AJR 2008; 190:226-232
© American Roentgen Ray Society
Cardiac Hydatid Disease: CT and MRI Findings
Memduh Dursun1,
Ege Terzibasioglu1,
Ravza Yilmaz1,
Bledi Cekrezi1,
Seref Olgar2,
Kemal Nisli2 and
Atadan Tunaci1
1 Department of Radiology, Istanbul University, Istanbul Faculty of Medicine,
Millet Caddesi, Capa, Istanbul, 34390 Turkey.
2 Department of Pediatric Cardiology, Istanbul University, Istanbul Faculty of
Medicine, Istanbul, Turkey.
Received February 9, 2007;
accepted after revision July 2, 2007.
Address correspondence to M. Dursun
(memduhdursun{at}yahoo.com).
FOR YOUR INFORMATION
A data supplement for this article can be viewed in the online version of
the article at:
www.ajronline.org.
Abstract
OBJECTIVE. The purpose of this article is to review the CT and MRI
findings of cardiac hydatid disease.
CONCLUSIONS. CT and MRI are helpful for localizing and defining the
morphologic features of hydatid cysts. Specific signs include calcification of
the cyst wall, presence of daughter cysts, and membrane detachment. CT best
shows wall calcification, whereas MRI depicts the exact anatomic location and
nature of the internal and external structures.
Keywords: CT • cardiac hydatid disease • MRI
Introduction
Hydatid disease is a parasitic infection caused by larvae of
Echinococcus granulosus, which is still endemic in many sheep-raising
countries. Domestic dogs and cats are the primary carriers of echinococcal
organisms. Humans are infected as intermediary carriers when they eat unwashed
and uncooked vegetables and swallow the ova of the parasite. After the person
digests the contaminated food, the embryo of the parasite is released into the
intestinal tract and carried to the liver by the portal circulation
[1]. Hydatid cysts are
surrounded by the periparasitic host tissue (pericyst) encompassing the
endocyst of larval origin. Inside the laminated layer, or hyaline membrane,
the cyst is covered by a multipotential germinal layer, which gives rise to
the production of brood capsules and protoscolices
[2].
Hydatid cysts can be located in various tissues, although they are most
common in the liver (50-70% of cases) and the lung (20-30% of cases) in humans
[3]. Cardiac involvement in
hydatid disease is uncommon, constituting only 0.5-2% of all cases of
hydatidosis [4]. Experience
with CT and MRI of persons with cardiac hydatid disease is limited
[5-9].
We present the CT and MRI findings of nine patients with cardiac hydatid
disease.
Imaging Technique
CT
Contrast-enhanced CT was performed on a 4-MDCT scanner (Somatom Sensation
4, Siemens Medical Solutions) and a helical CT scanner (Somatom Plus-S,
Siemens Medical Solutions). The MDCT parameters were as follows: 0.5-second
gantry rotation, 4 x 2.5 mm collimation, pitch of 6 (4 x 1.5),
30-mm/s table feed, and 2-mm image thicknesses. Helical CT was performed at
3-mm collimation and 4-mm table speed (pitch, 1.3).
MRI
Cardiac MRI was performed with a 1.5-T system (Symphony, Siemens Medical
Solutions) with ECG triggering. The MRI sequences were as follows: T1-weighted
spin echo (TR/TE, 700/26; matrix size, 133 x 256; slice thickness, 5
mm); T2-weighted spin echo (800/81; matrix size, 133 x 256; slice
thickness, 5 mm) echo-planar cine true fast imaging with steady-state
precession (50/1.70; matrix size, 256 x 256; slice thickness, 6 mm); and
dark-blood HASTE (800/26; matrix size, 256 x 256; slice thickness, 6
mm).
Heart Involvement
Areas of cardiac involvement in hydatid disease include the left ventricle
(60% of cases), right ventricle (10%), pericardium (7%), pulmonary artery
(6%), and left atrial appendage (6%); involvement of the interventricular
septum is rare (4% of cases). Cardiac involvement occurs by invasion of the
myocardium, first through the coronary artery circulation. The second route of
infestation is the pulmonary vein from rupture of pulmonary echinococcal cysts
into the vein. The left ventricle is more often involved than the right
ventricle, possibly because of the dominance of the left coronary artery,
which brings blood to the left ventricle; the greater myocardial mass in the
left ventricle, which provides optimal conditions for development of the
parasite; and the varying pressure conditions
[1,
10] (Fig.
1A,
1B; see
www.arjonline.org
for Fig. S1C).
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Fig. 1A —52-year-old woman with hydatid cyst in left ventricular apex. See
also Figure S1C, cine loop, in supplemental data online. Static image from
four-chamber cardiac MRI examination performed with cine true fast imaging
with steady-state precession shows hydatid cyst (arrow) with
hypointense ring-shaped thick wall in left ventricular apex.
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Fig. 1B —52-year-old woman with hydatid cyst in left ventricular apex. See
also Figure S1C, cine loop, in supplemental data online. Static image from
four-chamber cardiac MRI examination performed with cine true fast imaging
with steady-state precession shows left ventricular hydatid cyst
(arrow) and two huge cysts in liver (asterisks).
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Right-sided cardiac hydatid cysts have characteristics different from those
of left-sided cysts. Right-sided cysts have a tendency to expand
intracavitarily and subendocardially (Fig.
2A,
2B,
2C,
2D,
2E,
2F; see
www.arjonline.org
for Fig. S2G), and right ventricular cysts rupture more frequently, so they
lead to pulmonary embolus, anaphylaxis, or sudden death. Rupture into the
pericardial cavity can lead to pericarditis, effusion, and cardiac tamponade
(Fig. 2A,
2B,
2C,
2D,
2E,
2F), whereas left-sided cysts
tend to grow subepicardially
[2] (Fig.
3A,
3B). The heart also can be
secondarily affected by direct contact with hydatid cysts originating from the
liver or the lung (Fig. 4A,
4B,
4C).
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Fig. 2A —12-year-old girl with complicated pericarditis due to right
ventricular and pericardial hydatid cysts. See also Figure S2G, cine loop, in
supplemental data online. Short-axis HASTE dark-blood MR image (A) and
static image from cine true fast imaging with steady-state precession (FISP)
MRI examination (B) show hydatid cyst (asterisk) originating
from interventricular septum and growing into right ventricular cavity.
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Fig. 2B —12-year-old girl with complicated pericarditis due to right
ventricular and pericardial hydatid cysts. See also Figure S2G, cine loop, in
supplemental data online. Short-axis HASTE dark-blood MR image (A) and
static image from cine true fast imaging with steady-state precession (FISP)
MRI examination (B) show hydatid cyst (asterisk) originating
from interventricular septum and growing into right ventricular cavity.
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Fig. 2C —12-year-old girl with complicated pericarditis due to right
ventricular and pericardial hydatid cysts. See also Figure S2G, cine loop, in
supplemental data online. Static image from right-sided two-chamber cine true
FISP MRI examination shows multiloculated cyst (arrowhead) in
pericardium and right ventricular cyst (asterisk).
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Fig. 2D —12-year-old girl with complicated pericarditis due to right
ventricular and pericardial hydatid cysts. See also Figure S2G, cine loop, in
supplemental data online. HASTE dark-blood MR image 1 month after C,
when patient experienced acute precordial pain, reveals that cyst in right
ventricle had multiple curvilinear areas of low signal intensity indicating
germinative membrane (arrow) and intense pericardial effusion
(arrowheads).
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Fig. 2E —12-year-old girl with complicated pericarditis due to right
ventricular and pericardial hydatid cysts. See also Figure S2G, cine loop, in
supplemental data online. Static images from cine true FISP MRI examination
show multiple curvilinear areas of low signal intensity within pericardial
effusion (arrowheads) and pericardial thickening attributable to
pericarditis due to rupture of multiloculated cyst in pericardium.
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Fig. 2F —12-year-old girl with complicated pericarditis due to right
ventricular and pericardial hydatid cysts. See also Figure S2G, cine loop, in
supplemental data online. Static images from cine true FISP MRI examination
show multiple curvilinear areas of low signal intensity within pericardial
effusion (arrowheads) and pericardial thickening attributable to
pericarditis due to rupture of multiloculated cyst in pericardium.
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Fig. 3A —32-year-old man with left ventricular hydatid cyst. Static image
from four-chamber cine true fast imaging with steady-state precession MRI
examination shows subepicardial left ventricular cyst (arrow).
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Fig. 3B —32-year-old man with left ventricular hydatid cyst. Static image
from four-chamber cine true fast imaging with steady-state precession MRI
examination shows subepicardial hydatid cyst (arrow) with large base
(arrowheads) originating from cardiac apex.
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Fig. 4A —82-year-old woman with hepatic hydatid cyst. Heart has been
secondarily affected by cyst. Static image from cine true fast imaging with
steady-state precession coronal MRI examination shows large multiloculated
hydatid cyst (arrow) originating from liver and growing toward right
hemithorax.
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Fig. 4B —82-year-old woman with hepatic hydatid cyst. Heart has been
secondarily affected by cyst. Static images from four-chamber (B) and
short-axis (C) cine true fast imaging with steady-state precession MRI
examinations show marked narrowing of right atrial chamber (asterisk)
due to compression of hydatid cyst. Hydatid cyst (arrow, C) in
liver contains germinative membrane. rv = right ventricle, lv = left
ventricle, la = left atrium.
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Fig. 4C —82-year-old woman with hepatic hydatid cyst. Heart has been
secondarily affected by cyst. Static images from four-chamber (B) and
short-axis (C) cine true fast imaging with steady-state precession MRI
examinations show marked narrowing of right atrial chamber (asterisk)
due to compression of hydatid cyst. Hydatid cyst (arrow, C) in
liver contains germinative membrane. rv = right ventricle, lv = left
ventricle, la = left atrium.
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Arterial Involvement
Arterial involvement with a hydatid cyst usually develops after a cardiac
hydatid cyst ruptures and embolism of the germinative membrane causes acute
symptoms. Intravascular growth of a hydatid cyst is a rare manifestation of
disease and usually causes chronic arterial occlusion. Hydatid cyst inside the
pulmonary arteries is an exceptional localization and most frequently a
consequence of embolism from primary cardiac locations
[9]. Other hypotheses are that
the parasite can cross the arterial wall through previous small breaks in the
intima or aneurysms or by entering the vas nutritia
[8] (Fig.
5A,
5B,
5C,
5D).
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Fig. 5A —31-year-old woman with hydatid cyst in right pulmonary artery.
Contrast-enhanced CT image obtained with mediastinal window settings shows
small cyst within right pulmonary artery (arrow).
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Fig. 5B —31-year-old woman with hydatid cyst in right pulmonary artery.
Control CT image obtained 7 months after A shows enlargement of lesion
(arrow) within right pulmonary artery. Another cyst is present in
pulmonary trunk (arrowhead).
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Fig. 5C —31-year-old woman with hydatid cyst in right pulmonary artery. CT
scans 6 months after B show bilateral massive right (C) and left
(D) pulmonary artery embolisms (arrow) due to rupture of
pulmonary artery hydatid cysts. Patient had dyspnea and hemoptysis.
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Fig. 5D —31-year-old woman with hydatid cyst in right pulmonary artery. CT
scans 6 months after B show bilateral massive right (C) and left
(D) pulmonary artery embolisms (arrow) due to rupture of
pulmonary artery hydatid cysts. Patient had dyspnea and hemoptysis.
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Pericardial Involvement
Pericardial involvement in hydatid disease is rare (Figs.
6A,
6B and
7A,
7B,
7C,
7D) and frequently occurs as a
result of rupture of a primitive hydatid lesion, the location of which is
almost exclusively cardiac (Fig.
2A,
2B,
2C,
2D,
2E,
2F). Intrapericardial rupture
of a cyst can lead to pericarditis (Fig.
2A,
2B,
2C,
2D,
2E,
2F), effusion, and cardiac
tamponade, which can be fatal (22.5% of cases of intrapericardial rupture).
The cause is not so much the hydatid fluid contained in a large cyst but an
exaggerated exudative reaction of the serous membrane of the pericardium
[11].
Signs and Symptoms
Most patients with cardiac echinococcosis have no symptoms, and the disease
is often latent because a hydatid cyst in the heart grows very slowly. Unless
a cyst is located in a critical anatomic site, the disease is usually
diagnosed late [1]. Signs and
symptoms of cardiac hydatid cysts are extremely variable and directly related
to the location and the size of the cysts. Only approximately 10% of patients,
especially those with large hydatid cysts, have clinical manifestations.
Precordial pain is the most common symptom and is most often vague and does
not resemble angina pectoris. Precordial pain also can be of the pericardial
type, especially in patients with a pericardial hydatid cyst and a pericardial
reaction [11]. Sudden rupture
of intracardiac cysts is a frightful complication and can cause acute
pericarditis or tamponade
[11], acute pulmonary
hypertension by embolization of several scolices
[8,
9], systemic arterial
embolization, and severe anaphylactic shock. All complications can be
life-threatening [12].
Imaging Features
Echocardiography, CT, and MRI can show the cystic nature of the mass and
its relation to the cardiac chambers. CT best shows wall calcification (Fig.
8A,
8B,
8C; see
www.arjonline.org
for Fig. S8D). MRI depicts the exact anatomic location and nature of the
internal and external structures and is the technique used for posttreatment
follow-up [7]. The appearance
of a hydatid cyst on MRI is usually a characteristic oval lesion that is
hypointense on T1-weighted images and hyperintense on T2-weighted images (Fig.
9A,
9B,
9C; see
www.arjonline.org
for Fig. S9D). A typical finding on T2-weighted images is a hypointense
peripheral ring, which represents the pericyst (a dense fibrous capsule from
the reactive host tissue) [6,
8] (Figs.
1A,
1B and
8A,
8B,
8C). A variety of tumors in
the heart and a congenital pericardial cyst must be considered in the
differential diagnosis; however, the multivesicular nature of the cystic mass
and membrane detachment indicate the true diagnosis. The cysts may be single
or multiple (Fig. 7A,
7B,
7C,
7D), uniloculated or
multiloculated, and thin or thick walled. More specific signs include
calcification of the cyst wall, presence of daughter cysts (Fig.
9A,
9B,
9C), and membrane detachment
(Fig. 2A,
2B,
2C,
2D,
2E,
2F). The mass becomes solid and
can be difficult to differentiate from heart tumors
[12].
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Fig. 8A —1-year-old woman with esophageal carcinoma and incidentally detected
left ventricular hydatid cyst. See also Figure S8D, cine loop, in supplemental
data online. Contrast-enhanced CT image obtained to evaluate esophageal
carcinoma (asterisk) shows cystic lesion with small calcification in
inferior wall of left ventricle (arrow).
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Fig. 8B —1-year-old woman with esophageal carcinoma and incidentally detected
left ventricular hydatid cyst. See also Figure S8D, cine loop, in supplemental
data online. Static short-axis (B) and sagittal (C) images from
cine true fast imaging with steady-state precession MRI examination show
hypointense ring-shaped thick-walled hydatid cyst (arrow) in inferior
wall of left ventricle and esophageal carcinoma (asterisk,
C).
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Fig. 8C —1-year-old woman with esophageal carcinoma and incidentally detected
left ventricular hydatid cyst. See also Figure S8D, cine loop, in supplemental
data online. Static short-axis (B) and sagittal (C) images from
cine true fast imaging with steady-state precession MRI examination show
hypointense ring-shaped thick-walled hydatid cyst (arrow) in inferior
wall of left ventricle and esophageal carcinoma (asterisk,
C).
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Fig. 9A —45-year-old man with left ventricular hydatid cyst. See also Figure
S9D, cine loop, in supplemental data online. Four-chamber dark-blood spin-echo
T1-weighted MR image shows large hypointense intracavitary left ventricular
hydatid cyst (arrowheads).
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Fig. 9B —45-year-old man with left ventricular hydatid cyst. See also Figure
S9D, cine loop, in supplemental data online. Four-chamber dark-blood spin-echo
T2-weighted MR image (B) and static image from cine true fast imaging
with steady-state precession short-axis MRI examination (C) show
hyperintense cyst (arrowheads) that includes multiple daughter
cysts.
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Fig. 9C —45-year-old man with left ventricular hydatid cyst. See also Figure
S9D, cine loop, in supplemental data online. Four-chamber dark-blood spin-echo
T2-weighted MR image (B) and static image from cine true fast imaging
with steady-state precession short-axis MRI examination (C) show
hyperintense cyst (arrowheads) that includes multiple daughter
cysts.
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Treatment
Surgery remains the treatment of choice in the management of hydatid
disease. Although antihelminthic drugs have been used in the preoperative and
postoperative periods since 1977, extirpation of the lesion under
cardiopulmonary bypass is recommended
[1,
2].
References
- Onursal E, Elmaci TT, Tireli E, Dindar A, Atilgan D, Ozcan M.
Surgical treatment of cardiac echinococcosis: report of eight cases.
Surg Today 2001;31
: 325-330[CrossRef][Medline]
- Gormus N, Yeniterzi M, Telli HH, Solak H. The clinical and surgical
features of right-sided intracardiac masses due to echinococcosis.
Heart Vessels 2004;19
: 121-124[CrossRef][Medline]
- Sensoz Y, Ozkokeli M, Ates M, Akcar M. Right ventricle hydatid cyst
requiring tricuspid valve excision. Int J Cardiol2005; 101:339
-341[CrossRef][Medline]
- Perez-Gomez F, Duran H, Tamamer S, Perrote JL, Blanes A. Cardiac
echinococcosis: clinical pictures and complications. Br Heart
J 1973; 35:1326
-1331[Free Full Text]
- Cantoni S, Frola C, Gatto R, Loria F, Terzi MI, Vallebona A.
Hydatid cyst of the interventricular septum of the heart: MR findings.
AJR 1993; 161:753
-754[Free Full Text]
- Kotoulas GK, Magoufis GL, Gouliamos AD, et al. Evaluation of
hydatid disease of the heart with magnetic resonance imaging.
Cardiovasc Intervent Radiol 1996;19
: 187-189[Medline]
- Oueslati S, Said W, Saaidi I, et al. Imaging cardiac hydatid cysts:
8 cases. Presse Med 2006;35
: 1162-1166[Medline]
- Yague D, Lozano MP, Lample C, Nunez ME, Sanchez F. Bilateral
hydatid cyst of pulmonary arteries: MR and CT findings. Eur
Radiol 1998; 8:1170
-1172[CrossRef][Medline]
- Alper H, Yünten R, Sener NR. Intramural hydatid cyst of
pulmonary arteries: CT and MR findings. Eur J Radiol1995; 5:666
-668
- Makaryus AN, Hametz C, Mieres J, Kort S, Carneglia J, Mangion J.
Diagnosis of suspected cardiac echinococcosis with negative serologies: role
of transthoracic, transesophageal, and contrast echo-cardiography.
Eur J Echocardiogr 2004;5
: 223-227[Abstract/Free Full Text]
- Thameur H, Abdelmoula S, Chenik S, et al. Cardio-pericardial
hydatid cysts. World J Surg 2001;25
: 58-67[CrossRef][Medline]
- Ben-Hamda K, Maatouk F, Ben-Farhat M, et al. Eighteen-year
experience with echinococcosus of the heart: clinical and echocardiographic
features in 14 patients. Int J Cardiol2003; 91:145
-151[CrossRef][Medline]
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Abstract
Introduction
