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CT Angiography and Digital Subtraction Angiography in the
evaluation of atherosclerotic peripheral arterial disease pictorial essay.
Poster No.:
C-1638
Congress:
ECR 2013
Type:
Educational Exhibit
Authors:
J. A. Sousa Pereira, H. A. M. R. Tinto, L. Fernandes, T. Bilhim, Z.
Seabra; Lisbon/PT
Keywords:
Arteriosclerosis, Diagnostic procedure, Catheters, CTAngiography, Catheter arteriography, Interventional vascular
DOI:
10.1594/ecr2013/C-1638
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Learning objectives
Review the most adequate CT Angiography (CTA) protocols using a 64 multislice
computerized tomography scanner.
Review the most adequate techniques of Digital Subtraction Angiography (DSA).
Review the Radiological Anatomy of the lower limb arteries.
Review the most common CTA and DSA findings associated with atherosclerotic
peripheral arterial disease (PAD).
Compare the performance of CTA and DSA and evaluate CTA as a treatment planning
imaging technique.
Background
Atherosclerotic PAD is a common disorder, particularly in the elderly population with
cardiovascular risk factors.
Traditionally, pre-treatment assessment of PAD was performed with conventional
catheter angiography, however recent studies have shown that the overall diagnostic
performance of CTA is almost equivalent in the detection and staging of clinically relevant
PAD, allowing reliable therapeutic planning.
Imaging findings OR Procedure details
Retrospective study (January - August 2012) of patients who underwent lower extremity
CTA and DSA at our institution.
CTA protocol
CT angiography was performed with a 64-detector row unit (Lightspeed VCT; GE Medical
Systems, Milwaukee, Wis), from 2 cm above the origin of the celiac trunk to the foot
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(105-130m), by using the following parameters: collimation, 0.625 X 64 mm; gantry
rotation, 0.6-0.8 second; pitch, 1; noise índex, 32; scan duration,20-35 seconds.
Contrast enhancement was achieved with intravenous injection of 125 mL of nonionic
iodinated contrast medium (iomeprol, 320 mg of iodine per milliliter [Iomeron; Bracco,
Milan, Italy])after an injection of 30 mL of saline solution at a flow rate of 3,5-4 mL/sec.
Scan delay was individually determined by using bolus-tracking software (Smart-Prep,
GE Medical Systems). The scanning began 8 seconds after a threshold attenuation of
150 HU was reached in the abdominal aorta superior to the level of the renal arteries.
CT angiographic data sets were transferred to a dedicated GE workstation for
post processing. Reconstructed three-dimensional images included maximum intensity
projections (MIP), volume-rendered images, and curved multiplanar reformations along
the longitudinal axis of the artery.
DSA protocol
Conventional DSA was performed in the cases where endovascular revascularization
was indicated. The therapeutical procedures took place during the same session using
one standard angiographic unit (Innova 4100, GE Medical Systems, Milwaukee, Wis).
An interventional radiologist with 7 years of experience in vascular and interventional
procedures performed intra arterial DSA after catheterization through a femoral artery
access. An iodinated contrast agent (iomeprol, 320 mg of iodine per millilitre Iomeron;
Bracco, Milan, Italy]) was administered through a 4F sheath when an anterograde
puncture was performed (below the knee revascularization) or trough a 4F pigtail when
a retrograde puncture was performed (contra-lateral femoral-iliac revascularization).
Radiological anatomy of the lower limb arteries (Figures 1, 2, 3)
The common femoral artery (CFA) (Figure 1) begins immediately behind the inguinal
ligament, midway between the anterior superior spine of the ilium and the symphysis
pubis, and passes down the front and medial side of the thigh. After originating the
profunda femoris artery, it is also commonly known as the superficial femoral artery. It
ends at the junction of the middle with the lower third of the thigh, where it passes through
an opening in the Adductor magnus to become the popliteal artery.
The profunda femoris artery (deep femoral artery-DFA) (Figure 1) is a large vessel
arising from the lateral and back part of the femoral artery, from 2 to 5 cm. below the
inguinal ligament. At first it lies lateral to the femoral artery; it then runs behind it and the
femoral vein to the medial side of the femur, and, passing downward behind the Adductor
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longus, ends at the lower third of the thigh in a small branch, which pierces the Adductor
magnus, and is distributed on the back of the thigh to the hamstring muscles.
The popliteal artery (PA) (Figures 1,2) is the continuation of the femoral, and courses
through the popliteal fossa. It extends from the opening in the Adductor magnus, at the
junction of the middle and lower thirds of the thigh, downward and lateralward to the
intercondyloid fossa of the femur, and then vertically downward to the lower border of the
Popliteus, where it divides into anterior tibial artery and tibio-peroneal trunk.
The anterior tibial artery (ATA) (Figure 2) commences at the bifurcation of the popliteal,
at the lower border of the Popliteus, passes forward between the two heads of the
Tibialis posterior, and through the aperture above the upper border of the interosseous
membrane, to the deep part of the front of the leg: it here lies close to the medial side
of the neck of the fibula. It then descends on the anterior surface of the interosseous
membrane, gradually approaching the tibia; at the lower part of the leg it lies on this bone,
and then on the front of the ankle-joint, where it is more superficial, and becomes the
dorsalis pedis.
The arteria dorsalis pedis (ADP) (Fig. 3), the continuation of the anterior tibial, passes
forward from the ankle-joint along the tibial side of the dorsum of the foot to the proximal
part of the first intermetatarsal space, where it divides into two branches, the first dorsal
metatarsal and the deep plantar.
The posterior tibial artery (PTA) (Figure 2) arises from the tibio-peroneal trunk,
begining at the lower border of the Popliteus, opposite the interval between the tibia and
fibula; it extends obliquely downward, and, as it descends, it approaches the tibial side
of the leg, lying behind the tibia, and in the lower part of its course is situated midway
between the medial malleolus and the medial process of the calcaneal tuberosity. Here
it divides beneath the origin of the Adductor hallucis into the medial and lateral plantar
arteries.
The peroneal artery (PerA) (Figure 2) is deeply seated on the back of the fibular side
of the leg. It arises from the tibio-peroneal trunk, about 2.5 cm, below the lower border
of the Popliteus, passes obliquely toward the fibula, and then descends along the medial
side of that bone. It divides into lateral calcaneal branches which ramify on the lateral
and posterior surfaces of the calcaneus.
The lateral plantar artery (a. plantaris lateralis; external plantar artery) (LPA) (Fig. 3),
much larger than the medial, passes obliquely lateralward and forward to the base of the
fifth metatarsal bone. It then turns medialward to the interval between the bases of the
Page 4 of 18
first and second metatarsal bones, where it unites with the deep plantar branch of the
dorsalis pedis artery, thus completing the plantar arch.
The medial plantar artery (a. plantaris medialis; internal plantar artery) (MPA) (Figure3),
much smaller than the lateral, passes forward along the medial side of the foot.
Imaging findings
Atherosclerosis is the predominant cause of lower extremity ischemia, although
in younger patients or in patients with atypical histories or physical findings, non
atherosclerotic diseases should be considered.
Atherosclerotic plaques commonly calcify and produce focal, patchy, irregular
calcifications in the intima of the arterial wall. These calcifications are easily seen on
CT examinations of the extremities. Plaques may have a wide variety of angiographic
appearances, ranging from diffuse, relatively smooth narrowing of long arterial segments
to very focal web-like lesions. The distribution of atherosclerotic lesions in lower extremity
arteries is surprisingly symmetrical in most patients.
A fairly strong correlation exists between the extent of disease and clinical presentation,
although clinical symptoms may not be a good measure of angiographic progression of
disease. Patients with claudication usually have flow-limiting vascular lesions at one levelpelvis, thighs, or calves-compared to patients with limb-threatening ischemia in which
multiple proximal and distal arteries are involved.
Certain diseases associated with atherosclerosis have atypical and characteristic
angiographic patterns of arterial involvement.
Patients with diabetes have an increased frequency and severity of symptoms related
to peripheral vascular disease. Accelerated atherosclerosis largely confined to the
infrapopliteal arteries in the calf demonstrated has been demonstrated in these patients
(Figure 4).
The severity of disease correlates well with the duration of diabetes, independent of
patient age. Interestingly, the proximal lower extremity arteries seem to be relatively
spared and, in fact, seem to have less involvement than typical nondiabetic patients who
have peripheral vascular disease, producing the classic angiographic findings of normal
proximal vessels with severe disease in the tibial and peroneal arteries.
Page 5 of 18
Premature atherosclerosis is usually defined as symptomatic arterial obstruction in
patients younger than 50 years of age. It is often associated with a positive family history
and may be associated with hyperlipidemia and hipercoaguable states. As opposed
to diabetic vascular disease, premature atherosclerosis usually occurs in the proximal
arteries, mainly the distal aorta, iliac and femoral arteries (Fig 5).
Traditionally, pre-treatment assessment of PAD has been performed with conventional
catheter angiography. However, conventional angiography is an invasive procedure
that can have a complication rate (puncture site complication and catheter-related
complications) as high as 10%. The advent of alternative minimally invasive procedures,
such as multidetector CTA has markedly reduced the need for diagnostic catheter
angiography, effectively limiting its use to patients undergoing interventional treatment.
From our experience, we find an excellent agreement between the CTA and DSA findings
(Figures 6,7,8 and 9). Therefore, we confidently use CTA for diagnosis, therapeutical
decision and procedure planning.
Images for this section:
Page 6 of 18
Page 7 of 18
Fig. 1: CTA MIP (A) and 3D Volume Rendering (VR) (B) reformat of right tigh depicting
the normal anatomy. CFA-common femoral artery ; SFA-superficial femoral artery ;DFAdeep femoral artery; PA-popliteal artery.
Page 8 of 18
Page 9 of 18
Fig. 2: CTA 3D VR (A) and MIP (B) reformats of the right leg showing the normal infrapopliteal arterial anatomy. PA-Popliteal artery; TPT- tibio-peroneal trunk; ATA-anterior
tibial artery; PTA-posterior tibial artery; PerA- peroneal artery; PlaA-plantar artery; ADParteria dorsalis pedis.
Fig. 3: CTA 3D VR reformat of the right foot showing the normal arterial anatomy. ADParteria dorsalis pedis; MPA-medial plantar artery; LPA-lateral plantar artery; PA-plantar
arch.
Page 10 of 18
Page 11 of 18
Fig. 4: CTA 3D VR (A) and MIP (B) reformats of the lower extremity showing severe
atherosclerotic disease of the infra-popliteal segment, typical of diabetic peripheral
vascular disease.
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Page 13 of 18
Fig. 5: CTA 3D VR reformat of the lower extremity showing occlusion of both superficial
femoral arteries. Note that the below the knee segment does not show relevant
atherosclerotic disease. The diffuse calcifications of the left leg are dependent of severe
coexistent chronic venous insufficiency.
Fig. 6: MIP (A) and CTA 3D VR (B) reformat showing occlusion the distal third of left
SFA. Note the correlation between the CTA and DSA (C) findings. Post stenting DSA (C)
showing no residual stenosis and adequate run-off.
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Fig. 7: A. DSA bolus track fused image and B. CTA 3D reformat of left leg. Bothe
techniques are able to shown adequately severe atherosclerotic disease, with occlusion
lower 2/3 of the posterior tibial artery (thin arrow) with distal run-off at the plantar artery
(hooked arrow), and segmental occlusion of peroneal artery (arrowhead). Note also that
Page 15 of 18
there is an anastomosis between the peroneal and anterior tibial artery (thick arrow), from
which the dorsal pedal artery (curved arrow) arises.
Fig. 8: DSA (A) and CTA 3D VR reformat (B, C) of the infra-popliteal vessels. Note
the severe atherosclerotic disease with occlusion of the posterior tibial (arrowhead) and
peroneal arteries (curved arrow). The anterior tibial artery (thin arrow) does not show
significant stenosis.
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Fig. 9: DSA (A,D) and CTA MIP and 3D VR reformat (B,C,E) of right lower extremity
showing the correlation between the 2 techniques. Note the severe stenosis of the
popliteal (thin arrow) and the anterior tibial arteries (curved arrow). There is occlusion of
the tibio-peroneal trunk (arrowhead) with repermeabilization of the peroneal artery ( thick
arrow).
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Conclusion
Protocol optimization is essential for maximizing the diagnostic performance of CTA.
Knowledge of the arterial anatomy of the lower extremities and of the most frequent
findings in PAD is paramount for vascular and interventional radiologists.
There is excellent agreement between the CTA and DSA findings.
CTA allows a confident diagnosis of PAD, reliable therapeutical decision-making and
procedure planning.
References
Leskinen Y, Salenius JP, Lehtimaki T, et al. The prevalence of peripheral arterial disease
and medial arterial calcification in patients with chronic renal failure: requirements for
diagnostics. Am J Kidney Dis 2002;40(3):472-479.
Chantelau E, Lee KM, Jungblut R. Association of below-knee atherosclerosis to medial
arterial calcification in diabetes mellitus. Diabetes Res Clin Pract 1995;29:169-172.
Napoli A, Anzidei M, Zaccagna F et al. Peripheral Arterial Occlusive Disease: Diagnostic
Performance and Effect on Therapeutic Management of 64-Section CT Angiography.
Radiology 2011;261
Lezzi R, Santoro M, Marano R et al. Low-Dose Multidetector CT Angiography in the
Evaluation of Infrarenal Aorta and Peripheral Arterial Occlusive Disease. Radiology 2012;
263:1
Personal Information
[email protected]
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