Abnormal accumulation of [18F]fluorodeoxyglucose in the aortic wall
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Vol. 20, No. 5, 2006 Case Report361
Annals of Nuclear Medicine Vol. 20, No. 5, 361364, 2006
Received December 9, 2005, revision accepted March 3,
For reprint contact: Miwako Takahashi, M.D., Department of
Radiology, The University of Tokyo, Graduate School of Medicine,
Hongo, Bunkyo-ku, Tokyo 1130033, JAPAN.
FDG-PET imaging has played an important role in the
diagnosis of various malignant tumors. Increased glucose
transporter protein (GLUT) expression in various malignant
tumors has been reported and it is suggested that
increased GLUT expression contributes to increased FDG
uptake in PET imaging.15
Increased FDG uptake, however, is also observed in
various kinds of inflammatory lesions,6,7 which suggests
that FDG-PET imaging can be useful in localizing
inflammatory lesions in patients who show unspecific
general inflammatory and infectious findings.813
In this report, we show three cases with FDG uptake in
the arterial wall. The common features of these three cases
provide insight into the pathological changes that contribute
to intense FDG uptake and enhance the usefulness for
diagnosis of inflammatory diseases.
Fluorine-18-labeled deoxyglucose (FDG) positron emission
tomography (PET) scan of the whole body was
performed after a 6-hour fast. The scans started 60 minutes
after FDG injection at a dose of 296 MBq. Images
were reconstructed with OSEM methods.
A 57-year-old woman presented with a 3-month history of
fever, dizziness and cough. The patient was initially
treated with an antifebrile; however, her condition did not
improve. At the time of her presentation at our facility, she
had persistent elevation of C-reactive protein (CRP; 8.8
mg/dl), an accelerated erythrocyte sedimentation rate
(ESR; 116 mm), and elevated IL-2R (589 U/ml). PANCA,
C-ANCA and rheumatoid factors were negative.
Complement levels were slightly elevated. FDG-PET
scan showed increased FDG uptake in the thoracic and
abdominal aortic wall, and the uptake continued to the
main branches of the thoracic aorta (Fig. 1a, b, d). A
contrast-enhanced CT scan was taken 2 weeks after the
FDG-PET scan and demonstrated thickening of the aortic
wall (Fig. 1c). The localization of her inflammation in the
arterial wall by FDG-PET yielded a diagnosis of Takayasu
Abnormal accumulation of [18F]fluorodeoxyglucose
in the aortic wall related to inflammatory changes:
three case reports
Miwako TAKAHASHI, Toshimitsu MOMOSE, Masashi KAMEYAMA and Kuni OHTOMO
Department of Radiology, The University of Tokyo, Graduate School of Medicine
We present 3 cases with abnormal accumulation of FDG in the aortic wall. Their clinical
manifestations were vague or asymptomatic, and laboratory data were consistent with inflammatory
reaction. These 3 patients were diagnosed with Takayasu arteritis, inflammatory aortic aneurysm
(IAA), and retroperitoneal fibrosis (RF), respectively. FDG-PET and CT images showed the intense
FDG uptake corresponding to the arterial walls and/or the soft tissue density surrounding the artery.
It was deduced that FDG was probably taken up by inflammatory cells which infiltrated the arterial
walls and/or the soft tissue mass. These cases indicated that FDG-PET is a useful method for
localization of inflammatory lesion in patients with unspecific clinical findings and laboratory data.
Key words:Takayasu arteritis, inflammatory aortic aneurysm, retroperitoneal fibrosis, FDG,
362Miwako Takahashi, Toshimitsu Momose, Masashi Kameyama and Kuni Ohtomo Annals of Nuclear Medicine
arteritis. The diagnosis was confirmed by laboratory data
and improvement of her symptoms with the administration
A 54-year-old female underwent an FDG PET scan to
determine the possibility of an underlying residual malignant
lesion and distant metastasis at 4 years after liver
surgery for rectal cancer metastasis. FDG-PET showed
intense uptake of FDG in the aortic arch, and no other
abnormal findings were seen (Fig. 2a, b). CT showed a
dilated aortic arch and wall thickening, corresponding to
the intense uptake area on FDG PET (Fig. 2c, d). At the
time of the FDG-PET scan, her CRP was 1.5 mg/dl. She
had not complained of any inflammatory symptoms, such
as abdominal or back pain. After excluding possible
primary causes, diagnosis of inflammatory aortic aneurysm
was confirmed by typical radiological findings,
namely a thickened and dilated aneurysmal wall with
enhancement on contrast-enhanced CT.14
A 56-year-old male was referred to hospital for abdominal
pain. He received antibiotics initially; however, his symptoms
did not improve. CT showed abdominal aortic wall
thickening surrounded by soft tissue density. The soft
tissue density was enhanced and extended to the adjacent
structures. His laboratory data showed slightly elevated
C-reactive protein (CRP; 1.5 mg/dl) and an accelerated
erythrocyte sedimentation rate (ESR; 43 mm). He was
diagnosed with retroperitoneal fibrosis based on his clinical
and radiological findings. FDG-PET demonstrated
abnormal accumulation of FDG around the abdominal
aorta (Fig. 3a, b), and the intense uptake of FDG corresponding
to the arterial wall and the soft tissue densities
on his CT (Fig. 3c, d).
Fig. 1a, b: FDG-PET images show continuing uptake in the thoracic abdominal aorta, brachiocephalic
artery, common carotid arteries, and subclavian arteries. (a, maximum intensity projection (MIP); b,
coronal view.) c, d: CT images demonstrate aortic wall thickening (c). Intense abnormal FDG
accumulation is noted in the aortic wall (d). (c, contrast-enhanced CT; d, FDG-PET axial views
corresponding to the CT images.)
Fig. 2a, b: FDG-PET images demonstrate abnormal FDG accumulation in the aortic arch. Moderate
diffuse uptake is seen in the stomach (arrowhead). No other abnormal FDG uptake is seen. c, d: CT
images show a dilated thoracic aorta with wall thickening. FDG-PET demonstrates intense uptake
corresponding to the aneurysmal wall. (c, contrast-enhanced CT; d, FDG-PET axial views corresponding
to the CT images.)
Vol. 20, No. 5, 2006 Case Report363
We experienced 3 cases in which FDG uptake was shown
in aortic walls. All FDG-PET scans started 60 minutes
after the injection. It is reported that the amount of activity
remaining in the circulation after this time is minimal.15
Therefore, the FDG uptake in the aortic wall suggested
increased glucose metabolism due to pathological processes.
After administration, FDG is transported into glucoseconsuming
cells, metabolized by hexokinase, and accumulated.
FDG accumulation is not specific for malignant
tumors. Recent investigations have reported increased
accumulation of FDG in inflammatory lesions. Mochizuki
et al. reported that GLUTs expression was detected by
immunohistochemical study in inflammatory tissue, and
the inflammatory tissue showed [14C]FDG uptake higher
than that of normal control muscle.16 Therefore, FDG
accumulation in the aortic wall suggested the existence of
an inflammatory condition.
In Takayasu arteritis, the histological signs are focal
dissection and infiltration with epithelioid cell granulomas
and focal lymphoplasmocellular infiltration of the
adventitia and the peripheral layers of the media.17 The
inflammation, whose etiology is still unknown, primarily
involves the aorta and its major branches.18 Idiopathic
retroperitoneal fibrosis (IRF) and inflammatory aortic
aneurysms (IAA) include chronic periaortitis, which is a
spectrum of idiopathic disease characterized by a fibroinflammatory
reaction. Histological signs of the chronic
periaortitis are inflammatory infiltrate of the aortic
adventitial and retroperitoneum. In IRF, the aorta is
undilated and the retroperitoneal fibroinflammatory tissue
may or may not involve neighboring structures; in
IAA, the mass develops around a dilated aorta and usually
does not cause obstructions. Inflammatory changes are
found in all chronic periaortitis, regardless of the presence
of aneurysmal dilatation.19
In our cases, FDG was probably taken up by inflammatory
cells which infiltrated the aortic walls and/or the soft
tissue density around the artery. The higher accumulation
demonstrated the distribution of inflammatory cells, and
probably correlated with the grade of inflammatory activities.
Meller et al. suggested that FDG-PET was more
reliable than MRI in monitoring disease activity of aortitis
during immunosuppressive therapy.20
Takayasu arteritis and chronic periaortitis have a
chronic-relapsing course and usually progress. As these
diseases progress, arterial stenosis or the involvement of
adjacent structures may occur. The severe complications
of IAA or RF can be associated with eventual rupture.
Early diagnosis is important for the proper initiation of
treatment and can avoid these complications and manifestations.
21In RF, FDG-PET can help to detect the presence
of active inflammatory foci in the residual mass at the time
of disease relapse. We could identify inflammatory lesions
in the arterial wall of patients who showed unspecific
inflammatory symptoms, even in an asymptomatic state.
Therefore, FDG-PET has been proposed as a useful tool
for the detection of inflammatory changes in the arterial
We gratefully acknowledge the excellent technical assistance of
Tomohiko Saito, Hiroshi Kaibasawa, Syojiro Koyama, Yukihiro
Takeuchi, Seiji Kato, Department of Radiology, The University
of Tokyo Hospital.
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Fig. 3a, b: FDG-PET shows intense FDG uptake surrounding the abdominal aorta. c, d: CT images
show a soft tissue density area around the abdominal aorta and expanding to the inferior vena cava. Axial
view of FDG-PET demonstrates intense FDG accumulation corresponding to soft tissue density.
Normal physiologic radioactivity is also seen in the right kidney (arrowhead). (c, contrast-enhanced CT;
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