DOI:10.2214/AJR.05.1230
AJR 2007; 188:W269-W273
© American Roentgen Ray Society
Diagnosis of Clinically Unsuspected Posttraumatic Arteriovenous Fistulas of the Pelvis Using CT Angiography
Jennifer K. Chen1,
Pamela T. Johnson2 and
Elliot K. Fishman2
1 Johns Hopkins University School of Medicine, Baltimore, MD 21287-0801.
2 Russell H. Morgan Department of Radiology and Radiological Science, Johns
Hopkins University School of Medicine, 601 N Caroline St., Rm. 3251,
Baltimore, MD 21287.
Received July 15, 2005;
accepted after revision September 18, 2005.
Address correspondence to E. K. Fishman.
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Abstract
OBJECTIVE. Traumatic arteriovenous (AV) fistulas present with a
variety of clinical manifestations and may prove difficult to detect. The
clinical sequelae of undiagnosed AV fistulas are significant and include
dilatation of the vessels, venolymphatic trophic complications, and heart
failure. In this article, we report two rare cases involving long-standing
noniatrogenic AV fistulas of the pelvis that were detected using 64-MDCT
angiography (CTA) 14 and 20 years after a trauma.
CONCLUSION. With the increased use of CTA for the diagnosis and
follow-up of trauma patients, we might better detect AV fistula formation and
thereby prevent the onset of sequelae normally associated with chronically
undiagnosed AV fistulas.
Keywords: arteriovenous fistulas • CT • CT angiography • emergency radiology • MDCT • MDCT angiography • pelvic imaging • trauma
Introduction
Traumatic arteriovenous (AV) fistulas are abnormal and uncommon
communications between an artery and adjacent vein that occur after
simultaneous damage of the two vessels. Generally caused by penetrating trauma
from gunshot or stab wound [1],
AV fistulas present with a variety of clinical manifestations and often prove
difficult to detect [2]. If an
AV fistula remains undiagnosed, the left-to-right shunt can lead to
progressive dilatation of the afferent arteries and efferent veins, with
possible formation of pulsatile varices or venolymphatic trophic
complications, such as venous ulcerations
[3]. Over time, heart failure
may occur. As the delay in diagnosis and treatment increases, the likelihood
of full recovery decreases [1].
Clearly, an effective means of AV fistula detection is of paramount
importance.
To date, few cases have been reported involving a significant delay in the
detection of AV fistulas of the pelvis. Here, we report two rare cases
involving long-standing noniatrogenic AV fistulas of the pelvis that were
detected using CTA performed 14 and 20 years after a trauma. With the
increased use of CTA in the diagnosis and follow-up of trauma patients, we
might better detect AV fistula formation and thereby prevent the onset of
sequelae normally associated with chronically undiagnosed AV fistulas.
Materials and Methods
CT Technique
For each case presented, MDCT was performed using a 64-MDCT scanner
(Sensation 64, Siemens Medical Solutions, Malvern, PA). The scanning
parameters were 0.6-mm detector collimation, 0.75-mm slice thickness, 120 kVp,
and 150 mAs, and data were reconstructed at 0.5-mm intervals. Arterial phase
imaging was performed 25 seconds after the IV injection of 120 mL of iohexol
(Omnipaque 350, GE Healthcare). All data were transferred to a workstation
(Leonardo, Siemens) that was running In Space software (Siemens).
Three-dimensional volume-rendered and maximum-intensity-projection (MIP)
reconstructions were performed interactively. Review of the medical records
for these two cases provided correlation of the MDCT findings with surgery
(case 1) or conventional arteriography (case 2).
Results
Case 1
A 35-year-old man presented with swelling of the left leg. He had a history
of a gunshot wound 14 years earlier. CTA with 3D reconstructions showed an
11-cm venous varix in the pelvis arising off the femoral vein and early
filling of the vein due to an AV fistula from the superficial left femoral
artery (Fig. 1A,
1B,
1C,
1D,
1E). This AV fistula appeared
to be long-standing because the patient's left-sided musculature was enlarged
with hemihypertrophy. As a result of the prior gunshot wound, the patient had
a fragment of bone near the posterior left acetabulum. A duplex scan confirmed
the findings and showed no evidence of deep venous thrombosis.
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Fig. 1A —35-year-old man presented with swelling of left leg. CT angiography
was ordered for evaluation of pelvic mass. Patient had history of gunshot
wound to buttocks 14 years earlier. Axial contrast-enhanced arterial phase
MDCT scan shows 11-cm venous varix (V) in pelvis displacing bladder (B) to
right.
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Fig. 1B —35-year-old man presented with swelling of left leg. CT angiography
was ordered for evaluation of pelvic mass. Patient had history of gunshot
wound to buttocks 14 years earlier. Axial contrast-enhanced arterial phase
MDCT scan obtained through upper thighs shows evidence of arteriovenous
fistula with enlarged left femoral artery and vein and early filling of left
femoral vein. Note mild enlargement of left upper thigh musculature
(arrows).
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Fig. 1C —35-year-old man presented with swelling of left leg. CT angiography
was ordered for evaluation of pelvic mass. Patient had history of gunshot
wound to buttocks 14 years earlier. Three-dimensional reconstruction of
arterial phase data set with volume rendering from anterior perspective
depicts enlarged left femoral artery and vein, large venous varix (V) in
pelvis, and early opacification of inferior vena cava (IVC) (arrow),
all findings reflecting fistulous communication between left superficial
femoral artery and vein.
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Fig. 1D —35-year-old man presented with swelling of left leg. CT angiography
was ordered for evaluation of pelvic mass. Patient had history of gunshot
wound to buttocks 14 years earlier. Left anterior oblique volume-rendered
image elucidates connection (black arrow) of large pelvic varix (V)
to left femoral vein. Early filling of IVC (white arrow) is
noted.
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Fig. 1E —35-year-old man presented with swelling of left leg. CT angiography
was ordered for evaluation of pelvic mass. Patient had history of gunshot
wound to buttocks 14 years earlier. Anterior coronal volume-rendered
reconstruction with bones edited from data set shows fistulous communication
between femoral artery and vein (arrowheads), large venous varix (V)
in pelvis, and early filling of IVC (arrow).
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Surgery confirmed an approximately 1-cm fistula between the superficial
femoral artery and vein. The fistula was excised, and the left superficial
femoral artery was repaired. Pathology results confirmed the presence of a
fistula and yielded no evidence of a tumor. The patient had an uncomplicated
recovery.
Case 2
A 44-year-old man presented to an emergency department at an outside
institution with a right-sided headache associated with dizziness, nausea,
vomiting, and left arm tingling. He had a history of maxillofacial and pelvic
trauma, which had been treated by reconstruction, from a motor vehicle crash
20 years earlier. MRI of the head and neck showed multiple foci in the brain,
consistent with emboli, and a right carotid artery aneurysm.
The patient was admitted to our vascular surgery service for further
management and underwent carotid and cerebral angiography, which showed a
4.5-cm pseudoaneurysm off the right internal carotid artery that was treated
by stenting of the right internal carotid artery with coil embolization.
During cerebral angiography, the radiologist noted a possible pelvic AV
connection. Therefore, the patient underwent CT of the pelvis the next day.
Axial CT and CTA with 3D reconstructions showed an AV fistula between the
right internal iliac artery and vein at the level of the sciatic notch (Fig.
2A,
2B,
2C). At that site, there was
evidence of prior pelvic fracture involving the right acetabulum with
heterotopic bone formation, and hypertrophy of the right gluteal muscles was
also identified. The decision was made to wait for the patient to fully
recover from the carotid intervention before correcting the fistula. He has
had an uncomplicated recovery to date.
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Fig. 2A —44-year-old man was referred for CT after incidental detection of
suspected right internal iliac artery arteriovenous (AV) fistula seen during
performance of cerebral angiographic study. Pertinent history was pelvic
fracture 20 years earlier. Axial contrast-enhanced arterial phase MDCT scan at
S1 level shows evidence of hypertrophy of right gluteus medius (MED) muscle
and, to lesser degree, right gluteus maximus muscle. Dilated pelvic veins are
consistent with right internal iliac artery AV fistula.
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Fig. 2B —44-year-old man was referred for CT after incidental detection of
suspected right internal iliac artery arteriovenous (AV) fistula seen during
performance of cerebral angiographic study. Pertinent history was pelvic
fracture 20 years earlier. Anterior coronal volume-rendered CT angiogram
reveals enlargement of right internal iliac artery and vein and early filling
of inferior vena cava (IVC) (arrow). Evidence of prior right
acetabular fracture with extensive heterotopic bone is also shown.
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Fig. 2C —44-year-old man was referred for CT after incidental detection of
suspected right internal iliac artery arteriovenous (AV) fistula seen during
performance of cerebral angiographic study. Pertinent history was pelvic
fracture 20 years earlier. Coronal volume-rendered CT angiogram from posterior
orientation shows right-sided venous varicosity (arrowheads) due to
internal iliac AV fistula and posttraumatic heterotopic bone on right. Bullet
fragment (arrow) is seen in left buttocks. (Fig. 2 continues on
next page)
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Discussion
Traumatic AV fistulas commonly have a clinical presentation that is
difficult to diagnose, especially in light of the fact that fistulas may form
weeks to years after an injury
[1]. AV fistulas typically
present with a pulsatile hematoma, bruit, or thrill
[4]; however, these
characteristics may be hidden behind apparent signs of varicose veins and
chronic venous insufficiency, which might suggest postthrombotic syndrome
[5]. Machinery murmur has been
noted in most patients presenting soon after AV fistula formation and in
virtually all patients presenting long after AV fistula formation
[1].
Currently, the diagnosis of an AV fistula can be made using angiography,
duplex and color Doppler sonography, MRI, and CT
[2]. Although angiography has
been the most definitive diagnostic technique, it has been suggested that CTA
may actually be superior to angiography as the preliminary diagnostic tool
[4,
6]. Not only minimally
invasive, rapid, and accurate, CTA is also operator-independent and is less
expensive than conventional angiography
[7]. Increasingly recognized
for its applications in trauma patients with suspected vascular injury, CTA is
also now readily available in many emergency departments.
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Fig. 2D —44-year-old man was referred for CT after incidental detection of
suspected right internal iliac artery arteriovenous (AV) fistula seen during
performance of cerebral angiographic study. Pertinent history was pelvic
fracture 20 years earlier. Anterior oblique volume-rendered CT angiogram with
bones edited from data set shows fistulous communication between internal
iliac artery and vein and enlarged internal iliac artery, vein, and IVC
(arrow).
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Fig. 2E —44-year-old man was referred for CT after incidental detection of
suspected right internal iliac artery arteriovenous (AV) fistula seen during
performance of cerebral angiographic study. Pertinent history was pelvic
fracture 20 years earlier. Anterior oblique 3D reconstruction using maximum
intensity projection shows right internal iliac AV fistulous communication and
early filling of IVC (arrow).
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Fig. 2F —44-year-old man was referred for CT after incidental detection of
suspected right internal iliac artery arteriovenous (AV) fistula seen during
performance of cerebral angiographic study. Pertinent history was pelvic
fracture 20 years earlier. Posterior coronal volume-rendered CT angiogram with
overlying bone structures removed from image better defines site of
communication of AV fistula. Early filling of IVC (arrow) is
noted.
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With regard to AV fistulas, CTA allows users to find detailed information
about the size and location of the fistula and whether adjacent structures are
involved [2]. In the detection
of posttraumatic vascular lesions of the proximal extremities, including AV
fistulas, CTA has shown sensitivities ranging from 90% to 100% and
specificities ranging from 98% to 100%
[4,
6]. Studies in the literature
involving single-detector CT have suggested that CTA might be limited in
localizing AV fistulas in the absence of associated signs of vascular injury
such as pseudoaneurysms [6].
However, the increased anatomic coverage of MDCT enables rapid scanning of the
entire patient during the arterial phase
[8]. This increased capability
could potentially increase the detection of unsuspected AV communications
while simultaneously providing more detailed information about the anatomy of
the lesion.
In the two cases reported, MDCT angiography was effective in depicting AV
fistulas that were most likely caused by trauma sustained 14 and 20 years
earlier. These cases are extremely unusual because of the long delay in
detection after a trauma. There are a number of possible reasons why these AV
fistulas remained undiagnosed for such a long time. Fistula formation may have
been extremely delayed or physical examination manifestations may have been
difficult to interpret. The difficulty was no doubt compounded by the fact
that neither patient reported any symptoms during the interim between the
trauma and AV fistula diagnosis; in fact, the second patient still had not
reported any problems at the time of diagnosis.
Cases such as these underscore the importance of physician awareness of the
associated clinical findings in patients with a history of trauma affecting
the pelvis, including large varices and asymmetry in the pelvic or proximal
lower extremity musculature. Radiologists must be cognizant of the secondary
findings on CT, including early venous opacification and venous enlargement.
Complications of an AV fistula include hemihypertrophy of the musculature, as
shown in these two cases, and lower extremity ulcerations and heart failure
[3]. There is a lower
probability of a full recovery in the setting of a delayed diagnosis of an AV
fistula [1].
In summary, we have reported two cases of long-standing traumatic AV
fistulas that were not detected for a significant number of years. Despite the
rarity of such cases, the seriousness of potential sequelae indicates that
physicians must be aware of the potential for an absence of clinical
complaints and of the specific physical findings that may indicate an
unsuspected vascular abnormality. When an AV fistula is suspected, MDCT is an
excellent imaging technique for detection and 3D volume-rendered CTA serves to
delineate and display the anatomy of such lesions.
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Abstract
Introduction
