Surgical Neurology 64 (2005) 321 – 324
www.surgicalneurology-online.com

Aneurysm

Evaluation of a distal pericallosal artery aneurysm visualized
with 3-dimensional digital subtraction angiography:
case report and treatment implications
Graeme F. Woodworth, BSa,*, Matthew J. McGirt, MDb,
Richard Clatterbuck, MDb, Philippe Gailloud, MDc
a

The Johns Hopkins School of Medicine, bDepartment of Neurosurgery, cDivision of Interventional Neuroradiology, The Johns Hopkins Hospital,
Baltimore, MD 21224, USA
Received 23 September 2004; accepted 16 November 2004

Abstract

Background: Digital subtraction angiography (DSA) is considered the gold standard in the
evaluation of cerebrovascular structures. Recently, 3-dimensional DSA (3D-DSA) has been
increasingly used to obtain detailed information about the morphology and dimensions of
intracranial aneurysms. We report the case of a patient who presented with a distal pericallosal
artery aneurysm, which appeared by 2D imaging to be a fusiform, possible mycotic aneurysm. This
was then revealed to be a saccular bifurcation aneurysm by 3D-DSA. This additional information
changed the treatment plan for this patient from medical management to a surgical approach.
Case Description: The patient is a 56-year-old man with a history of hypertension and alcohol abuse
with withdrawal seizures, who presented with a large intracranial hemorrhage on initial computed
tomography scan. After stabilization with intracranial pressure management, the patient underwent
magnetic resonance angiography and 4-vessel DSA. These initial studies showed a distal, fusiform
pericallosal aneurysm consistent with a mycotic aneurysm. Rotational DSA was then used to
generate 3D images of the structure that revealed a saccular bifurcation aneurysm. This enabled the
decision to offer operative treatment rather than conservative medical management.
Discussion: This report highlights the value of 3D-DSA in establishing the appropriate treatment
plan for patients with unique cerebral aneurysms. The higher resolution images used in this case
provided information that was crucial in shifting the treatment focus from medical management, for
what appeared to be a mycotic aneurysm by traditional DSA, to surgical intervention, for a clear
hemodynamic aneurysm at a vessel bifurcation seen with 3D-DSA. Accurate preinterventional
evaluation and differential diagnosis are critical to designing the most effective lowest risk treatment
plan. The standard method in the diagnosis of cerebral aneurysms has been DSA. Yet, higher
resolution images of unclear or high-risk aneurysms are often required to guide clinical decision
making. The emergence of new, less invasive endovascular techniques for securing intracranial
aneurysms has placed greater emphasis on precisely defining the shape and dimensions of an
aneurysm. Three-dimensional DSA is currently the highest resolution imaging modality available for
the evaluation of intracranial aneurysms.
Conclusion: 3D-DSA was used to evaluate a small, distal pericallosal artery aneurysm and revealed
a saccular bifurcation aneurysm not visualized with magnetic resonance angiography and
conventional DSA. This additional resolution permitted the team to consider a surgical approach
for a patient who would have otherwise been treated medically. This high-resolution technique is

* Corresponding author. The Johns Hopkins School of Medicine, 1017 S. Bouldin St. Baltimore, MD 21224, USA. Tel.: +1 410 241 9381;
fax: +1 410 955 9126.
E-mail address: gw@jhmi.edu (G.F. Woodworth).
0090-3019/$ – see front matter D 2005 Elsevier Inc. All rights reserved.
doi:10.1016/j.surneu.2004.11.027

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G.F. Woodworth et al. / Surgical Neurology 64 (2005) 321–324

particularly useful in guiding clinical decision making in the context of aneurysms that carry a
relatively broad differential diagnosis, potentially high interventional risk, and unclear morphology.
D 2005 Elsevier Inc. All rights reserved.
Keywords:

3D imaging; DSA; Pericallosal artery aneurysms; Distal anterior cerebral artery

1. Introduction
Digital subtraction angiography (DSA) is considered the
gold standard in the evaluation of cerebrovascular structures
[7,14,15]. Recently, 3-dimensional DSA (3D-DSA) has
been increasingly used to obtain detailed information about
the morphology and dimensions of intracranial aneurysms
[2,3,8,19]. This is especially important in cases with smaller,
more distal aneurysms that carry a broader differential
diagnosis. We report the case of a patient who presented
with a distal pericallosal artery aneurysm, which appeared
by 2D imaging to be a fusiform, possible mycotic aneurysm.
This was then revealed to be a saccular bifurcation
aneurysm by 3D-DSA. This additional information changed
the treatment plan for this patient from medical management
to a surgical approach.
2. Case description
The patient is a 56-year-old man with a past medical
history significant for hypertension, alcohol abuse, and
alcohol withdrawal seizures. He was admitted after having
been found down in the street for an unknown period.
Initial exam showed the following vital signs: blood
pressure, 118/palpation; pulse, 107; and temperature,
95.88F. He was unresponsive, his pupils were constricted
bilaterally, and he was not reactive to light. Gag and
corneal reflexes were present. He localized to pain in his
upper extremities whereas extended in response to pain in
his lower extremities. Glasgow Coma Scale was 7 T, Hunt
and Hess grade 5. Head computed tomography (CT) in the

emergency department showed significant intraventricular
and parafalcine subdural hemorrhage with an additional
intraparenchymal component centered around the corpus
callosum—Fischer grade IV. An intraventricular catheter
was placed and he was then transferred to the neurointensive care unit for intracranial pressure monitoring and
management. Magnetic resonance (MR) angiography was
obtained on hospital day 3 and showed no evidence of an
aneurysm or arteriovenous malformation. Because of
continued suspicion that the patient harbored a cerebral
aneurysm, 4-vessel DSA was performed on hospital day
7. Multiple views were obtained including cross-compression of each carotid artery. Initial results showed a small,
approximately 2- to 3-mm, pseudoaneurysm arising from a
branch of the left pericallosal artery. This lesion was
visualized in the region of the previously noted intraparenchymal hemorrhage. The morphology and location of
the lesion as depicted by conventional DSA were consistent
with a mycotic aneurysm or cardiac myxoma-related
pseudoaneurysm (Fig. 1). A rotational angiogram of the
left common carotid artery was then performed (BN2000,
Toshiba, Japan). The rotational angiography settings were as
follows: contrast volume, 24 mL; contrast rate, 4 mL/s; and
tube rotation, 408 per second. The rotational data set was
then transferred to a computer workstation (Vitrea, Vital
Images, Plymouth, MN) and volume-rendered 3D reconstructions were generated. These images revealed a saccular
aneurysm located at a distal bifurcation of the left
pericallosal artery (Fig. 2). This additional information
changed the treatment plan to surgical intervention. The
patient was scheduled for the operation the following day;
however, his condition worsened significantly. His chest
x-ray revealed a bilateral pneumonia and pneumothoraces
requiring chest tube placement. After considering going
through with the procedure, the family and physician team
felt that the prognosis was now quite poor, and the
additional risk of surgical intervention was not warranted
at this time. The patient was allowed to convalesce yet
showed no signs of improvement. The family decided to
withdraw care; soon after, the patient died.

3. Discussion

Fig. 1. Conventional 4-vessel DSA image showing a sagittal view of the
aneurysm: a small, approximately 2- to 3-mm, pseudoaneurysm arising
from a distal branch of the left pericallosal artery.

This report highlights the value of 3D-DSA in establishing the appropriate treatment plan for patients with unique
cerebral aneurysms. The higher resolution images used in
this case provided information that was crucial in shifting
the treatment focus from medical management, for what
appeared to be a mycotic aneurysm by traditional DSA, to

G.F. Woodworth et al. / Surgical Neurology 64 (2005) 321–324

323

volumetric assessment of aneurysms [18]. The highresolution 3D images generated by 3D-DSA permit close
inspection of the aneurysm’s shape and size, thereby
empowering the clinical decision making process.

4. Conclusion

Fig. 2. High-resolution 3D image from a rotational angiogram of the left
common carotid artery revealing a saccular aneurysm located at a distal
bifurcation of the left pericallosal artery.

surgical intervention, for a clear hemodynamic aneurysm at
a vessel bifurcation seen with 3D-DSA.
Although less than 10% of all intracranial aneurysms are
thought to be mycotic in nature [5], most far distal
intracranial aneurysms are often thought to be mycotic or
infectious in origin due to relatively lower hemodynamic
stresses and more likely location for trapping infectious
debris. However, studies have found that saccular aneurysms of the distal pericallosal artery are also fairly common
[6,11,16,17]. As a group, distal anterior cerebral artery
aneurysms are fragile, frequently rupture prematurely during
exposure, and have a higher morbidity than expected from
their angiographic appearance and location [6,11]. Yet,
conservative treatment of these aneurysms has been shown
to carry a poor prognosis [6,21]. Therefore, accurate
preinterventional evaluation is critical to designing the most
effective lowest risk treatment plan.
For years, the standard method in the diagnosis of
cerebral aneurysms has remained DSA [4,7,14,15,20].
Advances in the technology of MR angiography and 3D
CT angiography have opened the door to less invasive
diagnostic techniques with the capacity for 3D rendering in
the evaluation of cerebral aneurysms [12,13,18]. However,
from the perspective of clinical decision making, conservative therapy, endovascular treatment, or surgical intervention, higher resolution is necessary to clarify the most
appropriate option and to reduce false negatives [4,18]. With
the emergence of new less invasive endovascular techniques
for securing intracranial aneurysms, preinterventional evaluation emphasis has shifted toward precisely defining
aneurysm morphology, particularly the relative shape and
dimensions of the dome and neck of the aneurysm. Recent
progress of rotational DSA has introduced 3D-DSA, which
joins the 3D reconstructions offered by MR and CT
angiography with the anatomic resolution of DSA
[1,9,10,18,20]. This technique has been proven to be
superior to CT angiography and MR angiography in the

In this report, MR angiography and conventional DSA
were used in the evaluation of a small, distal pericallosal
artery aneurysm, and showed both no aneurysm and
fusiform, likely mycotic aneurysm, respectively. Further
imaging with 3D-DSA revealed a saccular structure at a
vessel bifurcation. This additional resolution permitted the
physician team to consider a surgical approach for a patient
who would have otherwise been treated medically. Threedimensional DSA is currently the highest resolution
imaging modality available for the evaluation of intracranial
aneurysms. This technique is particularly useful in guiding
clinical decision making in the context of aneurysms that
carry a relatively broad differential diagnosis, a potentially
high interventional risk, and an unclear morphology.

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I have known a vast quantity of nonsense talked about bad men
not looking you in the face. Don’t trust that conventional idea.
Dishonesty will stare honesty out of countenance any day in the
week, if there is anything to be got by it.
— Charles Dickens
English Novelist, 1812 -70