EL-MINIA MED. BULL. VOL. 20, NO. 2, JUNE, 2009
Abdelghany et al
LOWER EXTREMITY ARTERIAL DISEASES; ASSESSMENT OF THE
DISTAL RUNOFF USING MULTIDETECTOR COMPUTED
TOMOGRAPHY ANGIOGRAPHY
By
Hosny S. Abdelghany, MD; Ahmed F. El-Gebaly, MD; Ehab A. Abdel-Gawad,
MBBCH, Enas A. A. Gawad, MD.
Department of Radiology, El Minia University
ABSTRACT:
Objective. The purpose of this study was to evaluate the accuracy of Multidetector
Computed Tomography (MDCT) in the evaluation of distal runoff in patients with
peripheral arterial diseases.
Subjects and Methods. Fifty patients with manifestations of peripheral vascular
disease were referred for digital subtraction angiography (DSA) also underwent CT
angiography (CTA). The distal runoff of each lower limb was divided into 13 arterial
segment. Findings were graded according to four categories: 1, normal (0% stenosis);
2, (10-49% stenosis); 3, (50-99% stenosis); 4, severe (occlusion); also effete of
calcification on the diagnostic accuracy of CT angiography was evaluated. CTA
findings were compared with DSA findings for each arterial segment.
Results. For the distal runoff, sensitivity, specificity, PPV and NPP and accuracy
were 85.3%, 70.3%, 95.2 %, 42.7 % and 85.6 respectively.
Conclusion. Multidetector CT angiography is a reliable, noninvasive technique for
the imaging of the distal runoff in the absence of sever continues circumferential wall
calcifications.
KEYWORDS:
Lower limb
Multidetector CT
Ischemia
Angiography
fibrodysplasia, non-specific aortoarteritis (Takayasu disease), and a host of
uncommon vasculitides, the most
important of which is thromboangitis
obliterans (Buerger's disease),3 congenital connective tissue diseases such as
Marfan syndrome, Ehlers-Danlos
syndrome.4
INTRODUCTION:
Lower
extremity
arterial
diseases (also known as peripheral
arterial disease or PAD) represent a
significant health problem with increased morbidity and mortality. It can
be sub-classified into; steno-occlusive,
aneurysmal, vasculitis, traumatic vascular injuries and abnormal arteriovenous communications. In occlusive
disease lumen is narrowed either in an
acute or chronic manner.1
The imaging standard of reference
for complete delineation of the
peripheral vasculature is digital subtraction angiography (DSA). DSA,
however, is invasive and exposes the
investigator and patient to a lot of
ionizing radiation.5
Atherosclerosis is the most
common form of chronic peripheral
vascular disease.2 Other causes of PAD
include embolism, aneurysmal disease,
popliteal artery entrapment syndrome,
cystic adventitial disease, arterial
DSA also is a time and cost
consuming procedure, and at some
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EL-MINIA MED. BULL. VOL. 20, NO. 2, JUNE, 2009
institutions, at least one night of
hospitalization is mandatory. Finally,
DSA results only in luminograms, and
thus information about plaque constituents and vessel surroundings cannot
be acquired.6
Abdelghany et al
A retrospective analysis of 40
patients resulted in 520 distal runoff
arterial segments, of which 13
segments were considered non assessable, so the total number of assessable
distal runoff segments examined by
CTA and DSA was 507 segments.
Vascular risk factors are summarized
in table 1. All MDCT angiography
were done on 64 and 16 MDCT
scanner (GE CVT, Milwaukee,
Wisconsin, USA) and (GE Light
speed, Milwaukee, Wisconsin, USA)
with section thickness of (0.6mm),
with helical scan mode, table Pitch
(0984:1 and 1.75 :1 respectively), table
movement (39.7 and 17 respectively),
dose modulation. Scanning was done
in two stations from just below the
dome of the diaphragm below knee
then from above knee to the foot,
Contrast material (Omnipaque 350, GE
Healthcare Inc.Princeton, NJ) was
injected via the inserted canula at a rate
of 5 ml /sec. with an average total
amount of 150ml, using a compatible
pump injector for both machines
(Stellant D CT injector, MEDRAD,
INC, USA.(
Multi-detector computed tomography angiography (MDCT angiography) of the lower extremity has
high accuracy for detection of stenoocclusive diseases compared with
DSA. Its advantages over DSA includes minimal invasiveness, smaller
required volume of contrast material,
shorter scan time and fast data acquisition. Other advantages of MDCT
angiography include three dimensional
(3D) volumetric data analysis and
display, visualization of mural plaque
and
calcium.
Unlike
catheter
angiography, MD-CTA not only
depicts the vessels but also allows
assessment of perfusion in adjacent
organs. These advantages have led to
CTA replacing DSA for diagnosis at
many centers.7
PATIENTS AND METHODS:
Table 1: Vascular risk factors in the 50 patients.
Risk factor
Diabetes mellitus
Hypertension
Cardiac
Hyperlipidemia
Smoking
NO
22
13
15
17
18
RESULTS:
There were 25 men and 15
women with a median age of 63 (range
49-83), clinical presentation was lower
extremity arterial diseases of variable
degrees. The distal runoff was divided
into 13 segments, these
are the
tibioperoneal trunk, ATA (proximal,
middle and distal segments), PTA
(proximal, middle and distal seg-
%
55%
32.5%
37.5%
42.5%
45%
ments), peroneal artery proximal,
middle and distal segments), dorsalis
pedis artery, medial planter arch and
lateral arch. Stenosis was graded by
using a four-point Likert scale. Grade 1
indicated (normal or <10% luminal
narrowing). Grade 2 indicated (10%–
49% luminal narrowing). Grade 3 50%
– 99% luminal narrowing). Grade 4
indicated arterial occlusions. Planter
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EL-MINIA MED. BULL. VOL. 20, NO. 2, JUNE, 2009
arches and dorsalis pedis arteries were
assessed only for patency or
occlusions. Arterial stenosis with a
grade of 1 or 2 (<50% luminal narrowwing) was considered to be hemodynamically insignificant, whereas
arterial stenosis with a grade of 3 or 4
(50%–100% luminal narrowing) was
considered hemodynamically significant. Image quality was considered
diagnostic if all diagnostic information
were adequ-ately obtained, non
diagnostic if diagnostic information
Abdelghany et al
could not be obtained due to
inadequate vessel opacification or
haziness of the segment. Calcifications
also were evaluated as grade 0 =no
calcifications, grade 1=less than 50%
of the wall have classification, 2=more
than 50% wall calcification, and
3=circumferential wall calcification.
For the runoff station sensitivity, specificity, and accuracy were
85.3%, 89.3%, and 85.6 respectively.
SENSITIVITY SPECIFICITY ACCURACY
Runoff
85.39%
89.3%
Sensitivity, specificity, and accuracy of
MDCT angiography for the runoff.
85.6%
For grade 1 calcifications, sensitivity,
specificity, PPV and NPV were 94.2%,
66.7%, 87.6% and 82.1% respectively.
For grade 2 calcifications, sensitivity,
specificity, PPV and NPV were 91.8%,
NA, 77.1 % and NA. For grade 3
calcifications, sensitivity, specificity,
PPV and NPV were 83.5%, NA, 60%
and NA respectively.
For the runoff station and after
analyzing the effect of calcification on
the diagnostic performance of MDCT
(for grade 0 calcifications, sensitivity,
specificity, PPV and PPV were 100%,
93.8%, 84.3% and 100% respectively.
Grade 0 Calcif.
Grade 1 calcif.
Grade 2 calcif.
Grade 3 calcif.
Sensitivity
100%
94.2%
91.8%
83.5%
Secificity
93.8%
66.7%
NA
NA
+ve PPV
84.3%
87.6%
77.1%
60%
-ve PPV
100%
82.1%
NA
NA
Effect of calcifications on the sensitivity, specificity, PPV and NPV of MDCT
angiography of the distal runoff
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EL-MINIA MED. BULL. VOL. 20, NO. 2, JUNE, 2009
Abdelghany et al
70 yeas old male presented with color changes limb. Coronal maximum intensity
projection (MIP) and volume rendering (VR) images from CTA angiography show
occlusion of the middle and distal third of the three runoff vessels.
65 years old male presented with cold right foot. Coronal MIP in AP projection
images from CTA show, occlusion of the calf arteries at the region of the trifurcation
on the right side, as well as occlusion of the proximal PTA, lower peroneal artery and
whole ATA on the left side.
45 years old male with cold limb. Coronal MIP from MDCT angiography revealed a
filling defect at the bifurcation of the popliteal artery into tibioperoneal trunk and
ATA (arrow), DSA confirms the embolus at the trifurcation
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EL-MINIA MED. BULL. VOL. 20, NO. 2, JUNE, 2009
Abdelghany et al
The aim of our study was to
focus on the distal runoff because these
vessels may sometimes represent a
diagnostic dilemma because of their
relative small caliber and also these
vessels are frequently found calcified
especially in very old and diabetic
patients, also the clinical decision
needs and assessment of the distal
runoff.
DISCUSSION:
Angiography via an arterial
catheter is the gold standard in imaging
of the arterial system of the lower
limbs. It provides high resolution
imaging of the entire lower limb
vascular tree and allows percutaneous
vascular intervention at the same
sitting. However, it requires arterial
puncture with its attendant complications. Furthermore, it can fail to
demonstrate eccentric stenoses.8
Romano et al.11 evaluated
twenty two patients with peripheral
arterial diseases and reported a
sensitivity and specificity of 93% and
95%, respectively with an overall
diagnostic accuracy of 94%, our results
were inferior to their results, this is in
our opinion attributed to the smaller
number in their study, also they
estimated the overall sensitivity,
specificity and accuracy, however in
our study we calculated the sensitivity,
specificity and accuracy for the distal
runoff only these are excepted to have
inferior figures.
Several non-invasive imaging
modalities exist. Doppler ultrasound,
which is widely available and free
from side effects, is particularly suited
to imaging of the femoropopliteal and
calf vessels. However, imaging of the
aortoiliac segment is frequently compromised owing to overlying bowel
gas.
MR angiography is a valuable
technique in the assessment of arteries
of the pelvis and lower limbs. This
technique is non-invasive and requires
no ionizing radiation. Access to MR
remains limited and a significant minority of patients do not tolerate MRI.9
In a study done by Michael et
al 12, they revealed sensitivity and
specificity of MDCT angiography for
depicting hemnodynamically signifycant arterial stenoses and occlusions of
88.6% and 96.7%, which is almost the
same as in our study. The lower
sensitivity in our study (85.3%) is
attributed to that 21 arterial segments
were considered patent in CTA while
interpreted as occluded in DSA.
Computed tomographic (CT)
angiography is increasingly used for
noninvasive imaging of various vascular territories. The introduction of
multi–detector row CT scanners has
substantially improved CT angiography. It requires only venous
vascular access and is an outpatient
examination with minimal risk. MDCT
is now widely available and easily
tolerated by most of patients. It offers
volume coverage, with decreased dose
of contrast medium, decreased
acquisition time and this is important
in ill and emergency patients and in
children, and improved spatial resolution for assessment of smaller arterial
branches, including the aortoiliac and
lower extremity arteries.10
Arterial wall calcifications can
be a serious problem in the visualization of the real lumen. Ouwendijk
R et al 13, found significant change in
diagnostic accuracy and interobserver
agreement in arterial segments with
calcifications than in segments without
calcifications.
Furthermore, some authors10
stated that when extensive calcifi-
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EL-MINIA MED. BULL. VOL. 20, NO. 2, JUNE, 2009
cations are present, the end product of
CT angiography is of questionable
diagnostic value at best and that, in
these cases, patients could not be
treated without undergoing DSA for
accurate evaluation
Abdelghany et al
3. Rudofsky G. Peripheral arterial
disease: chronic ischemic syndromes.
In: Lanzer P, Topol EJ, eds. Pan
Vascular Medicine. Berlin: Springer;
2003; 1363–1422.
4. Tim
Leiner,
Dominik
Fleischmann, Neil M. Rofsky . Lower
extremity vasculature IN: Geoffrey D.
Rubin MD, Neil M. Rofsky MD et al.
CT and MR Angiography: Comprehensive Vascular Assessment, 1st
Edition. Lippincott Williams &
Wilkins, 2009.
5. Waugh JR, Sacharias N.
Arteriographic complications in the
DSA era. Radiology 1992; 182:243–
246.
6. Mathis
Prokop,
Michael
Galanski, Art J. van der Molen,
Cornelia Schaefer-Prokop. Spiral and
multislice Computed Tomography of
the body. New York, NY: Thime,
2003.
7. B.C. Meyer, A. Oildenburg,
B.B. Frericks, C. Ribbe, W.
Hopfenmuller, K.-J. Wolf, T. qalbrecht. Quantitative and qualitative
evaluation of the influence of different
table feed on visualization of peripheral arteries in CT angiography of
aortoiliac and lower extremity arteries.
Eur radiol 2008; 18: 1546-1555.
8. B Tins, MD, FRCR J Oxtoby,
MRCP, FRCR and S Patel. Comparison of CT angiography with conventional arterial angiography in aortoiliac occlusive disease. ritish Journal
of Radiology 74(2001),219-225.
9. Sueyoshi E, Sakamato I,
Matsuoka Y, Ogawa Y, Hayashi H,
Hashmi R, et al. Aortoiliac and lower
extremity arteries: comparison of
three-dimensional dynamic contrastenhanced subtraction MR angiography
and conventional angiography. Radiology 1999; 210: 683–688.
10. Ofer A, Nitecki SS, Linn S, et
al. Multidetector CT angiography of
peripheral vascular disease: a prospective comparison with intraarterial
In a study done Hideki O et al
, they evaluated the effect of mural
calcifications on the diagnostic performance of MDCT angiography, they
stated that there is a
significant
negative effect
in specificity and
accuracy of MDCT, they reported a
sensitivity of 95%, specificity of
89.7% and accuracy of 84.2%. In our
study we found that calcifications
affecting less than the whole
circumference of the arterial wall did
not significantly affect the accuracy of
CT angiography in assessing the runoff
vessels, however sever circumferential
wall calcifications especially when
continuous and in along segment can
significantly affect the accuracy of
CTA. So old patients (>80 years) and
patients with long standing DM with
lower extremity arterial diseases, MR
angiography can be a good alternative
non invasive imaging tool.
14
In conclusion, the results of our
study demonstrated that MDCT
angiography is and accurate minimally
invasive diagnostic tool in evaluation
of lower extremity distal runoff in
patients with lower extremity arterial
diseases provided there is no severe
circumferential wall calcification.
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‫‪Kazumasa Igarashi, Yoshihiro Chiba,‬‬
‫‪Kenichi Haga, Haruo Saito, Shoki‬‬
‫‪Takahashi. MDCT Compared with‬‬
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‫الملخص العربي‬
‫تعتبر أمراض شرايين األطراف السفليي مفن المشف ال الةفاي الةطيفرم زالمت‪.‬ايفىمت زنفن تافزن تي ف‬
‫ضيق أز ا سىاى في الشرايين أز تي تمىى غير طبيعي به ز الته ب ت أالزعيه الىمزي أز الازاىث زغير ذلك‬
‫من األسب بت‬
‫زيعتر تةيب الشرايين نز السبب األاثر شيزع في أمراض األطراف السليي ت‬
‫زلقى ا ن تةزير الشرايين ب ألشع الع ىي زالتةةيم الرقمي مع استةىام الةبغ ت المعتم نز ا فر ال‪.‬ازيف‬
‫زاألس س في تشةيص أمراض الشرايينت زلان نذا اللاص معقى الن اى م زقى ي تج ع ه بعض المة طر مثل‬
‫ال ‪.‬يف من ما ن الاقن ام ا ه قى بتطيب بق ء المريض ب لمستشلن يزم عين األقلت‬
‫زا ن البى من استاىاث زس ئل أاثر سهزل زام في التشةيص فا ن الفىزبير الميفزن فهفز متف م زامفن زلا فه‬
‫يتطيب زقت ابيرا في اللاص ز يعتمى بةزرم ابيرم عين ةبرم من يقزم بهت ام ا ه ةعب في المرضن ذزى‬
‫السم الع لي زالتايس ت الشىيىمت‬
‫زاآلن تم استاىاث األشع المقطعي متعىىم المق طع ب لامبيزتر زنن تتمي‪ .‬ب لسرع الشىيىم ففي‬
‫اللاص‪ ,‬فمثال فاص شرايين األطراف السليي ابتىاء مفن الشفري ن الارقلفن اتفن القفىم ال يسفتغر ااثفر مفن‬
‫‪20‬الن‪ 30‬ث يه فقطت ز ظرا لهذه السرع مع إما ي اةذ مق طع رقيق ىا عيه تستةىم في تةزير الشرايين‬
‫مع استةى ام الةبغ ت المعتم ت زاستةىام األشع المقطعي في فاص شفرايين األطفراف السفليي لفه العىيفى مفن‬
‫الممي‪.‬ات فهز فاص سريع زامن زقييل إن لم يان م عفىم المةف طر زال يتطيفب بقف ء المفريض ب لمستشفلن بعفى‬
‫إ راء اللاصت ام ا ه م سب في ا الت الطزارئ زاألطل ل زيتمي‪ .‬نفذا للافص أيضف بز فزى ةفزر ثالثيف‬
‫االبعى ليشرايين مع إما ي تةزير الشرايين من ‪.‬زاي متعىىه ام ا ه يظهر التايسف ت زيعطفن ةريطف ا ميف‬
‫عن شرايين األطرافت‬
‫زنذه الىراس ق مت عين ‪ 40‬مريض يع زن من أمراض شرايين األطراف السليي زا ن نفىفه‬
‫نز معرف مىى ىق نذا ال زع من اللازةف ت ففي تةفزير شفرايين األطفراف السفليي زة ةف شفرايين أسفلل‬
‫الراب زمعرف مىى إما ي استةىامه في تشةيص الضيق زاال سىاى في نذه الشرايينت زقى ةيةفت الىراسف‬
‫أن نذا اللاص امن زىقيق زيمان االعتم ى عييه في تشةيص نذا ال زع من األمراضت‬
‫‪238‬‬