DOI:10.2214/AJR.05.0631
AJR 2007; 188:W409-W411
© American Roentgen Ray Society
Bronchial Arteriovenous Malformation: MDCT Angiography Findings
Daiji Uchiyama1,
Kiminori Fujimoto1,
Masafumi Uchida1,
Masamichi Koganemaru1,
Tadashi Urae2 and
Naofumi Hayabuchi1
1 Department of Radiology, Kurume University School of Medicine, 67 Asahi-machi,
Kurume, Fukuoka 830-0011, Japan.
2 Department of Radiology, Yokokura Hospital, Omuta, Japan.
Received April 12, 2005;
accepted after revision June 24, 2005.
Address correspondence to K. Fujimoto
(kimichan{at}med.kurume-u.ac.jp).
WEB This is a Web exclusive article.
Keywords: arteriovenous malformation of bronchial artery • chest • congenital malformations • MDCT • MRI • 3D CT
Introduction
Primary bronchial arteriovenous malformation (AVM) is an extremely
rare congenital disease characterized by enlarged convoluted vessels and
anomalous communication between the bronchial artery and pulmonary artery or
pulmonary vein (bronchopulmonary shunt). The bronchial arteriography and
hemodynamic findings of this condition have been reported
[1-3].
To our knowledge, however, primary bronchial AVM diagnosed using reconstructed
3D images of contrast-enhanced MDCT has not been previously described. We
report the usefulness of multiphase fusion 3D images (i.e., superimposed
display of the arterial and venous phases) of MDCT in one case.
Case Report
A 77-year-old woman without symptoms underwent low-dose helical chest CT
without a contrast medium for a lung cancer screening project, and an
oval-shaped lesion in the right superior paravertebral region was detected
(Fig. 1A). The patient was a
lifelong nonsmoker. Physical examination and laboratory study results were
normal, and she had no past history of disease. MRI was performed for a
suspected neurogenic tumor. Transverse section images of T1-weighted fast
spin-echo sequences revealed a signal void in the paravertebral lesion (rapid
blood flow) (Fig. 1B). An
abnormal tortuous signal void (arterial flow), which arose from the descending
thoracic aorta, was depicted on a coronal T1-weighted image
(Fig. 1C).
Because bronchial arterial disorders, such as aneurysm and AVM, were
suspected, contrast-enhanced MDCT was performed on the abnormal opacities
using the following protocol. MDCT angiography was performed using a 16-MDCT
scanner (Aquilion, Toshiba Medical Systems) with beam collimation, 16 x
1 mm; 120 kV; 150 mAs; rotation time, 0.5 second; and pitch, 1.44:1. The
scanning range was 182 mm (the distance between the sternoclavicular joint and
diaphragmatic dome). The patient was instructed to hold her breath (25
seconds), with full inspiration during scanning.
A test injection was made of 20 mL of contrast medium (iopamidol [Iopamiron
370 mg I/mL, Nihon Schering]) at a rate of 3.5 mL/s for determining the chest
circulation time for the contrast-enhanced imaging (120 kV; 50 mAs; rotation
time, 30 seconds). Immediately after the administration of contrast medium, 30
mL of physiologic saline (sterile isotonic 0.9% saline solution) was
administered at a rate of 3 mL/s with an autoinjector (Dual-Shot,
Nemoto-Kyorindo) via the cubital vein. As a result of the test injection,
scanning was started 9 seconds (pulmonary artery phase) and 23 seconds
(pulmonary vein and thoracic aorta phase) after initiation of the contrast
injection; the former was termed the "venous phase" and the latter
was termed the "arterial phase." In these scans, 40 mL of
Iopamiron 370 mg I/mL at 3.5 mL/s and 50 mL of 0.9% physiologic saline (at 3
mL/s) were used.
Three-dimensional reconstruction was performed with a section thickness of
1 mm and a reconstruction interval of 0.6 mm. After completion of 3D CT data
acquisition, the arterial phase image was colored red and the venous phase
image was colored blue manually. The fusion image was made by superimposing
the arterial phase image on the venous phase image using a workstation
(M900QUADRA, Zio Software).
The 3D-reconstructed arterial phase and venous phase fusion image
(Fig. 1D) clearly revealed an
enlarged and tortuous bronchial artery (shown in red) arising from the
descending aorta, initially ascending and then descending toward an aneurysmal
change on the right posterior basal pulmonary artery
(Fig. 1E). The right posterior
basal pulmonary artery was colored red, and the thoracic aorta and bronchial
artery, in contrast to other pulmonary arteries, were colored blue because of
differing attenuation values obtained from region-of-interest
measurements.
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Fig. 1D —77-year-old woman with bronchial arteriovenous malformation.
Three-dimensional reconstructed arterial phase and venous phase fusion image
in posterior view clearly shows enlarged and tortuous bronchial artery
(red) arising from descending aorta. Note focal enlargement of
bronchial artery (arrow) corresponding to oval-shaped lesion in
A.
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Fig. 1E —77-year-old woman with bronchial arteriovenous malformation. MDCT
angiography close-up image shows abnormal bronchial artery (arrows)
continuing to aneurysmal change (arrowheads) adjacent to right
posterior basal pulmonary artery (PA). PV = pulmonary vein, LA = left
atrium.
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These CT findings indicated a left-to-right shunt, forming a communication
between the bronchial artery and pulmonary artery through a vascular
aneurysmal change. There was no evidence of abnormality in the lung parenchyma
found on CT. On the basis of these findings, a diagnosis of primary bronchial
AVM was made. The patient was asymptomatic and no angiography or treatment was
performed. The bronchial AVM had not changed in size or shape on follow-up
MDCT angiography 16 months after initial MDCT.
Discussion
Bronchial AVM is a rare disease
[1-3].
The nomenclature has been confused by use of terms such as angioma,
hemangioma, fistula, and malformation
[1-3].
This disease has been included as a type of pulmonary AVM
[4]. Four percent of all
congenital pulmonary AVMs have a feeder artery arising from the systemic
circulation, but the bronchial artery is rarely involved
[3].
Iwasaki et al. [2] reported
that hyperplastic changes in the bronchial arteries often develop secondarily
after inflammatory lung disease or pulmonary neoplasm. Cain and Spanel
[5] proposed that cases without
inflammation be called "primary angioma arteriovenosum racemosum"
(the same disorder of the present case). To differentiate between primary
(congenital) or secondary (due to inflammatory lung disease or pulmonary
neoplasm) bronchial AVM, we propose the following diagnostic criteria: normal
blood examination results, normal lung findings on chest radiography or CT,
and no history of lung disease. Thus, the present case fits the criteria for
the primary type.
Although the genesis of bronchial AVM remains uncertain
[2,
3,
6], most malformations are
believed to be congenital, such as developmental anomaly. It has been reported
that bronchopulmonary anastomosis at the precapillary level exists in the
normal lung [7], and
progressive enlargement occurs with age in response to increasing flow, with
eventual necrosis of the vessel wall
[6]. This might increase the
magnitude of the shunt or cause hemorrhage, leading to clinical detection.
Bronchial AVM can present at any age, occurs predominantly in men
[2,
3], and is usually unilateral
(especially in the middle and lower lobes) in the right lung more often than
in the left lung [3]. The chief
complaints are a potentially life-threatening or recurrent hemoptysis and
cough [1,
3], but bronchial AVM is rarely
found incidentally as an asymptomatic disease
[3]. Chest radiography findings
reveal no evidence of abnormality, parenchymal infiltrates, or increased
vascular markings [3]. No
abnormalities were revealed on the chest radiograph in the present case.
MDCT angiography findings for analyzing hemodynamics and bronchial AVM
morphology have not been previously reported. In the present case, 3D fusion
images obtained by superimposition of the arterial phase on the venous phase
indicated an abnormal course and form of the bronchial artery and a
left-to-right shunt forming a communication between the bronchial artery and
the pulmonary artery. Histopathologic specimens were not obtained, but these
CT findings were consistent with bronchial AVM.
Cases have been reported with conventional CT or bronchial arteriography
and treatment
[1-3].
With the recent development of novel techniques, MDCT angiography is a useful
method for evaluating the hemodynamics and morphology of abnormal vessels
without routine angiography. In the presented methods, a dual injector (one
holding a syringe with contrast medium and the other holding a syringe with
physiologic saline) was required to differentiate the effects of contrast
medium concentrations on the pulmonary arteries from those on the pulmonary
vein, aorta, and bronchial artery.
Haage et al. [8] reported
that the injection of 60 mL of 370 mg I/mL of contrast medium followed by a
30-mL saline bolus allows equal or better quality imaging and a reduction of
opacification in the superior vena cava when compared with 75 mL of the same
contrast material without saline. Although the total amount of contrast medium
generally used for thoracic helical CT varies between 75 and 150 mL
[8], the present method
required only 60 mL (20 mL in the test injection and 40 mL in MDCT
angiography). Furthermore, diluting chest blood with physiologic saline can
reduce perivenous artifacts, particularly in the superior vena cava.
For the treatment of a life-threatening or recurrent hemoptysis, surgical
resection of the aneurysmal change in the lung parenchyma, ligation of the
bronchial artery, and bronchial artery embolization have been reported
[1-3,
6]. However, the natural course
of this condition remains uncertain, and the necessary radical treatment has
not been established
[1-3,
6]. In the present case,
because the patient was asymptomatic and the left-to-right shunt and small
aneurysmal change were not considered to be life-threatening, we did not
perform further examinations or therapy.
In conclusion, MDCT angiography is a noninvasive technique for evaluating
hemodynamics and abnormal conditions of the bronchial artery without bronchial
arteriography. In addition, MDCT angiography using the presented methods can
reduce the total amount of contrast material and avoid perivenous artifacts
caused by the contrast medium.
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Introduction
Case Report
