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(IJCSIS) International Journal of Computer Science and Information Security,
Vol. 9, No. 3, March 2011
Evolution Prediction of the Aortic Diameter Based on
the Thrombus Signal from MR Images on Small
Abdominal Aortic Aneurysms
A. Suhendra1, C.M. Karyati2, A.Muslim3, A.B. Mutiara4
Faculty of Computer Science and Information Technology, Gunadarma University
Jl. Margonda Raya No.100, Depok 16424, Indonesia
1,2,3,4
{adang,csyarah,amuslim,amutiara}@staff.gunadarma.ac.id
Abstract—The paper is about studying the T1 and T2 from parts of the human body. The human blood pressure will refer
Magnetic Resonance (MR) Images examination for the existence to how much pressure in the arteries that brings blood to all
of thrombus in patient with Small Abdominal Aortic Aneurysms cells of the human body through the delicate vessels
(SAAA) in order to know whether thrombus signal has (capillaries) which then will return to the heart through blood
correlation with the evolution of aortic diameter enlargement, vessels and takes oxygen through the lungs. There are a little
which then can be used to predict the risk of rupture of aortic description of the aorta which will be discussed further in this
wall. Data were derived from 16 patients with SAAA, whereas study. It could be imagined if there are any damage to the
MR images obtained from 3T imager (Trio TIM, Siemens human aorta would result in abnormalities in blood flow in the
Medical Solution, Germany), which came from: the study of
human body. In the following image, we can see the anatomy
anatomy, cine-MR images, pictures T1/T2, blood flow images,
and images after injection of contrast agents. The surface area of
of the aorta and the arteries (figure 1) :
the aorta and luminal are determined by tracing manually, which
can be used to determine the surface area of thrombus. The
maximum diameter of the aorta are automatically obtained from
manual tracing on T1 images. The parameters to study the
thrombus signal are the mean, median, standard deviation,
skewness and kurtosis. Each parameter is calculated on the area
of thrombus, while for normalization we implement the signal in
the muscles. All parameters are compared to evolution of aortic
diameter. We found 13 out of 16 patients with SAAA have
thrombus. But there is no correlation between thrombus signals
and maximum diameter (mean (r = 0.318), median (r = 0.318),
skewness (r = 0.304)), or even with maksimum evolution diameter
(mean (r=0.512)). As the conclusion is the comparation between
mathematical and visual calculation of thrombus categories
reached 81% similar, but thrombus signal itself cannot be used to
Figure 1. Anatomy of the aorta [1]
predict the evolution of aortic diameter.
The Studies of human aorta have been conducted and
Keywords-component; Thrombus signal; evolution of aortic
diameter; T1 and T2 weighted images; Small Abdominal Aortic successfully detected abnormalities in the aortic wall, both at
Aneurysms. the thoracic or abdominal aortas [1,2]. In general, the swelling
of the aortic wall is very elastic, therefore if the swelling is
occur then aortic wall will not be able to shrink back and it will
I. INTRODUCTION be broken without being able to predict when the rupture risk
Aorta is the larger artery that delivers blood from the heart of the aortic wall. It could be in the risk of patient death.
of human beings throughout the body. In this way, the human
An Abdominal Aortic Aneurysm, also called AAA, is a
blood flow will go through some branch, for example, that led
bulging area in the wall of the aorta which is causing of an
to the arm (subclavian arteries), heading toward of the head
abnormal widening or ballooning until greater than 50 percent
(carotid arteries), and headed toward of the chest (thoracic
of the normal diameter. The the swelling of the aortic wall
aorta), then toward of the diaphragm to the stomach
could be caused by age (more than 60), male (four to five times
(abdominal aorta). In the region around the stomach will be
greater than females), family history (first degree relatives such
much more branching, including to the liver, intestines and
as father or brother), genetic factors, hyperlipidemia (elevated
kidneys. And last, the branching will be forwarded to the
fats in the blood), hypertension (high blood pressure), smoking
direction of human legs (iliac arteries).
and diabetes.
Human blood will be pumped by the heart into the aorta,
which then flows through the artery and its ramifications to all
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ISSN 1947-5500
(IJCSIS) International Journal of Computer Science and Information Security,
Vol. 9, No. 3, March 2011
Asymptomatic aneurysms may not require surgical According to the result of clinical data, there are difference
intervention until they reach a certain size or are noted to be characteristics based on status of each patient (smoking/ex
increasing in size over a certain period of time. The parameters smoking, fat in blood (dyslipidemied), and hypertency) as
for surgical decisions, but are not limited to, are as follows shown in Table I.
[1,2]:
• aneurysm size greater than 5 centimeters (about two
inches)
• aneurysm growth rate is arround 0.5 centimeters
(slightly less than one-fourth inch) over a period of six
months to one year
• patient’s ability to tolerate the procedure
II. TROMBUS SIGNAL
Thrombosis term will refer to the formation of a blood clot
(thrombus) in the blood vessels or human heart cavities.
Abdominal Aortic Aneurysms are often associated with the (a)
thrombus (clots). This field have been studied and
demonstrated by the pathological, surgical, and clinical
examination based on the results of computed tomography
(CT), ultrasound imaging, angiography, traditional spin-echo
(SE) or cine-MRI. There are many methods have been created
or modified to prove the existence of intact thrombus signal in
the aorta. But until now, with a disorder that occurs in the
aorta, it is difficult to detect or properly evaluate the existence
of thrombus signal [2, 3].
(b)
Figure 3. (a) T1- image and (b) T2- image at the level of Abdominal Aortic
Aneurysms
TABLE I. PATIENT’S CHARACTERISTICS
Figure 2. Aneurysms with a formation of Thrombus [4] Age
Name of Patient Sex Characteristics
(year)
The selection of images for thrombus formation analyzing Patient 1 Male 65 Smooking
is very important. Images are selected from the result of
examination during relaxation took place (as shown in Figure 3 Patient 2 Female 68 Dyslipidémie
of T1 and T2 images)[5]. Smooking, Hypertensi,
Patient 3 Male 62
Dyslipidémie
This work analysed the T1 and T2 of thrombus of SAAA
patient examination to determine whether the thrombus signal Patient 4 Male 82 Ex Smooking
has correlation with the aortic diameter enlargement, and to Patient 5 Male 83 -
predict the rupture risk of the aorta wall.
Patient 6 Male 59 Ex Smooking
III. MATERIALS AND METHODS Patient 7 Male 53 -
Ex Smooking,
A. Data Patient 8 Male 79 Hypertensi,
Data were obtained from 16 patients with Small Abdominal Dyslipidémie
Aortic Aneurysms (SAAA) who have been examined since Ex Smooking,
July 2006 until January 2010. Each patient has been examined Patient 9 Male 77 Hypertensi,
at least 1 to 4 times with examination period between 6 to 12 Dyslipidémie
months (depend on the patient). MR Images were acquired on a Patient 10 Male 71 Smooking,
3T Imager (Trio TIM, Siemens Medical Solution, Germany).
15 http://sites.google.com/site/ijcsis/
ISSN 1947-5500
(IJCSIS) International Journal of Computer Science and Information Security,
Vol. 9, No. 3, March 2011
Age
Name of Patient Sex Characteristics
(year)
Dyslipidémie
Patient 11 Female 74 Ex Smooking
Patient 12 Male 69 -
Ex Smooking,
Patient 13 Male 55 Hypertensi, (a) (b)
Dyslipidémie
Ex Smooking,
Patient 14 Male 51
Dyslipidémie
Ex Smooking,
Patient 15 Male 73 Hypertensi,
Dyslipidémie
Patient 16 Male 59 Smooking
(c)
Figure 5. (a) Anterior-Posterior Diameter, (b) Transversal Diameter, (c)
B. Protocol Small Abdominal Aortic Aneurysms Maximum Diameter
In this study protocol, images originating from: the study of
anatomy, cine-MR images for 3D/4D modeling, images T1/T2,
blood flow images, and images after injection of contrast
agents have been used to study the aspects of inflammation.
For each patient, the images are located in the same position
between one to another examination.
C. Processing
We used MatLab software to precess the data. Preliminary
examination has been conducted for predictive aspect, and final (a) (b)
examination has been conducted as well for data which has
more important thrombus, more areas, and more signals. The
borders have been manually traced to define the Aorta Surface
and Luminal Surface, therefore Thrombus Surface = Aorta
Surface – Luminal Surface, (see figure 4).
In aortic wall surface calculation, thrombus is found if the
thrombus surface area is greater than 30% of aortic surface (c)
area. Diameter of aorta is achieved by tracing manually the
aorta surface. There are three kinds of diameter positions: Figure 6. (a) T1-W image and (b) T2-W image after manual tracing, (c)
Normalization area in the muscle
Anterior-Posterior Diameter, Transversal Diameter and
Maximum diameter, as shown in the figure 5.
D. Paramaters
The muscle signal are slightly differences among each
examinations, therefore we normalized the data of muscle area. Maximum aortic diameter was automatically obtained from
manual tracing on T1 image in all examinations. Then we
calculated the evolution of the aortic diameter (mm/year) = ∆
maximum diameter (mm) / ∆ examination date (day) * 365
days. Several parameters were used to study the thrombus
signal, such as mean, median, standard deviation, skewness that
describes the degree of asymmetry of the signal histogram by
using the equation ∑ni(xi-x)3/Ns3, and the kurtosis that
describes how sharp the peak of the signal histogram which is
defined by using the equation ∑ni(xi-x)4/Ns4-3, where ni is
number of pixel at aorta xi , x is mean value of the aorta, s is the
(a) (b) SD, and N is the total number of pixels. [5]
Each parameter is calculated for the thrombus area, and the
Figure 4. (a) Manual tracing in Aorta Surface, (b) Manual tracing in Luminal signal in the muscle is used to normalize the mean of signal in
Surface (in green line)
thrombus, the median of signal in thrombus and the standard
deviation of signal in thrombus. These parameters are
compared to the evolution of the aortic diameter. By using
16 http://sites.google.com/site/ijcsis/
ISSN 1947-5500
(IJCSIS) International Journal of Computer Science and Information Security,
Vol. 9, No. 3, March 2011
mean/median/SD signal of the aorta and normalized Patient Thrombus Categories Thrombus Categories
mean/median/SD signal of muscle, the thrombus is classified as (based on parameters) (based on visualization)
follow: Homogeneous Thrombus (if T1 = T2 = Low signal); Patient 5 Heterogeneous Heterogeneous
Patient 6 Indefinite Indefinite
Heterogeneous Thrombus (if T1 = T2 = High signal); and Patient 7 Heterogeneous Heterogeneous
Indefinite Thrombus (if T1 ≠ T2 (low and high signal, or high Patient 8 Homogeneous Heterogeneous
and low signal)). Patient 9 Heterogeneous Heterogeneous
Patient 10 Heterogeneous Heterogeneous
IV. RESULTS AND DISCUSSION Patient 11 Homogeneous Heterogeneous
Patient 12 Homogeneous Heterogeneous
We found 13 out of the 16 patients with SAAA have a Patient 13 Homogeneous Homogeneous
thrombus. Figure 7 and 8 are a sample of T1 image which can Patient 14 Heterogeneous Heterogeneous
describe about presence of thrombus in SAAA. Patient 15 Heterogeneous Heterogeneous
Patient 16 Homogeneous Homogeneous
Figure 7. Surface thrombus : 243mm² (11,6%) without thrombus (a)
(b)
Figure 9. P13, Male, 55, ex smooking, hypertensi, dyslipidémie, ∆ Max
Diameter = 2.80 mm/year, 40% surface thrombus, Homogeneous T1 = T2 =
Figure 8. Surface thrombus : 1026mm² (48,4%) with thrombus
Low, T1= 0.391 < 0.815, (b) T2= 0.327 < 0.788
Based on height’s distribution of thrombus signal, there
were 3 patient without thrombus, 5 patiens with homogenous
thrombus, 7 with heterogeneous thrombus and 1 with indefinite
thrombus. Figure 9, 10, and 11 shows the categories of
thrombus presence. If we compare the used of parameters to
the visual, there were 3 differences of the result of thrombus
categories as shown in Table II. There are three categories are
different (patient number 8, 11, 12). It indicates that 81,25% of
thrombus categories determination using parameters are the
same with the result of based on visualization.
(a)
TABLE II. COMPARISON WITH VISUALIZATION CATEGORIES
Patient Thrombus Categories Thrombus Categories
(based on parameters) (based on visualization)
Patient 1 Without thrombus Without thrombus
Patient 2 Without thrombus Without thrombus
Patient 3 Homogeneous Homogeneous
Patient 4 Without thrombus Without thrombus
17 http://sites.google.com/site/ijcsis/
ISSN 1947-5500
(IJCSIS) International Journal of Computer Science and Information Security,
Vol. 9, No. 3, March 2011
and Table IV). From those tables, there are many values of R <
0.3 (not good correlation), a few values of R > 0.3, which
indicates a correlation between thrombus signals and the
evolution of the aortic diameter.
TABLE III. PARAMETERS VS MAXIMUM DIAMETER
Name of T1 T2
Comparison
(b) R² R Equation R² R Equation
Mean/Mean 0.099 0.314 y = 0.030x – 0.010 0.098 y = 0.005x +
Figure 10. P5, Male, 83, ∆ Max Diameter = 2.27 mm/year, 90.85% surface Muscle 0.325 0.485
thrombus, Heterogeneous T1 = T2 = High, (a) T1= 2.675 > 0.815, (b) T2 = Mean/Median 0.099 0.314 y = 0.030x – 0.045 0.212 y = 0.012x +
0.881> 0.788 Muscle 0.329 0.253
Mean/SD 0.006 0.078 y = 0.041x + 0.071 0.266 y = 0.145x +
Muscle 4.002 6.542
Median/Mean 0.101 0.318 y = 0.031x – 0.009 0.097 y = 0.005x +
Muscle 0.364 0.471
Median/Median 0.101 0.318 y = 0.031x – 0.045 0.212 y = 0.011x +
Muscle 0.368 0.249
Median/SD 0.008 0.089 y = 0.045x + 0.063 0.252 y = 0.136x +
Muscle 3.774 6.483
SD/Mean 0.055 0,234 y = 0.005x + 0.004 0.063 y = -0.002x +
(a) Muscle 0.038 0.340
SD/Median 0.055 0,234 y = 0.005x + 0.005 0.069 y = 0.005x +
Muscle 0.0383 0.176
SD/SD Muscle 0.000 0.001 y = -0.000x + 0.000 0.005 y = 0.001x +
1.550 4.873
Skewness 0.093 0.304 y = -0.011x + 0.015 0.121 y = -0.007x +
0.549 0.669
Kurtosis 0.000 0.010 y = -0.000x + 0.040 0.200 y = -0.025x +
2.321 3.649
TABLE IV. PARAMETERS VS ∆ MAXIMUM DIAMETER
(b)
Name of T1 T2
Comparison
Figure 11. P6, Male, 59, ex smoking, ∆ Max Diameter =1.33 mm/year, 6.93% R² R Equation R² R Equation
surface thrombus, Indefinite T1 = Low ≠ T2 = High, (a) T1= 0.691 < 0.815,
(b) T2 = 0.853 > 0.788 Mean/Mean 0.262 0.512 y = 0.024x + 0.029 0.171 y = -0.004x +
Muscle 0.931 0.717
Then all parameters for generate thrombus categories that have Mean/Median 0.001 0.028 y = -0.010x + 0.019 0.134 y = -0.024x +
Muscle 1.125 0.843
correlation with the evolution of aortic diameter compared
with parameters that don’t have correlation with the evolution Mean/SD 0.031 0.176 y = -0.101x + 0.014 0.112 y = -0.160x +
Muscle 5.441 12.953
of aortic diameter which is indicated by many occurrence of
value r <0.3 (r is the coefficient of determination on the
graph). But there are also some parameters indicate a linear Median/Mean 0.000 0.02 y = -0.007x + 0.019 0.137 y = -0.018x +
Muscle 1.109 0.705
correlation between thrombus signal with a maximum
Median/Median 0.001 0.022 y = -0.008x + 0.019 0.137 y = -0.022x +
diameter, where the mean value (r = 0.314), median (r = Muscle 1.123 0.798
0.318), skewness (r = 0.304), or thrombus signal with the Median/SD 0.024 0.154 y = -0.091x + 0.013 0.114 y = -0.156x +
evolution of maximum diameter (mean (r = 0.512). Muscle 5.391 12.437
But there are some parameters that showed a linear
correlation between thrombus signal with a maximum diameter SD/Mean 0.002 0.044 y = 0.003x + 0.022 0.148 y = -0.011x +
Muscle 0.250 0.327
(mean (r = 0.314), median (r = 0.318), skewness (r = 0.304)) or
SD/Median 0.002 0.04 y = 0.002x + 0.027 0.163 Y = -0.013x +
correlation between thrombus signal and the evolution of Muscle 0.252 0.361
maximum diameter (mean (r = 0.512) (as shown in Table III
18 http://sites.google.com/site/ijcsis/
ISSN 1947-5500
(IJCSIS) International Journal of Computer Science and Information Security,
Vol. 9, No. 3, March 2011
SD/SD Muscle 0.005 0.07 y = 0.010x + 0.010 0.102 y = -0.060x + REFERENCES
1.266 5.277
[1] Health Library, Aneurysm Overview, New York-Presbyterian Hospital,
30 Novembre 2008
Skewness 0.046 0.215 y = -0.021x + 0.000 0.017 y = 0.003x + [2] Shin Ito, Koichi Akutsu, Yuiichi Tamori, Shingo Sakamoto, Tsuyoshi
0.178 0.479 Yoshimuta, Hideki Hashimoto, Satoshi Takeshita, Differences in
Atherosclerotic Profiles Between Patients With Thoracic and Abdominal
Kurtosis 0.021 0.146 y = -0.016x + 2.000 0.005 y = 0.002x + Aortic Aneurysms, The American Journal of Cardiology, Volume 101,
2.367 2.855 Issue 5, Pages 696-699, 1 March 2008
[3] Toshio Honda, Mareomi Hamada, Yuji Matsumoto, Hiroshi Matsuoka,
Kunio Hiwada, Diagnosis Thrombus and Blood Flow in Aortic
Aneurysms by use of Tagging Cine MRI, International Journal of
V. CONCLUSION Angiology, 6:203-206, 1997
[4] M. Xavier, A. Lalande, P.M.Walker, C. Boichot, A. Cochet, O. Bouchot,
The similarity level between thrombus catagory and E. Steinmetz, L. Legrand, F. Brunotte, Dynamic 4D Blood Flow
visualization is 81.25%. There are no good correlation between Representation in the Aorta and Analysis From Cine-MRI in Patients,
thrombus signal and evolusi of aortic diameter on SAAA Computers in Cardiology, 34:375−378, 2007
(many values of r < 0.3), therefore thrombus signal itself [5] Marco Castrucci et al, Mural Thrombi in Abdominal Aortic Aneurysms:
cannot be used as parameter to predict the evolution of aortic MR Imaging Characterization-Useful before Endovascular Treatment ?,
diameter. The correlation between blood flow, thrombus signal RSNA, 197, Italy, October 1995
and bilogy is still studied. For the next research, we will [6] Christopher M. Kramer, Magnetic Resonance Imaging Identifies the
Fibrous Cap in Atherosclerotic Abdominal Aortic Aneurysm ,
implement other comparation parameters to aortic diameter, Circulation ; 109 ; 1016-1021, 2004
such as: blood flow speed with 3D/4D modeling (The aspect of [7] Eric M. Isselbacher, Thoracic and Abdominal Aortic Aneurysms ,
laminar and turbulance, maximum spped, radial speed, and Circulation, 2005
shear stress). and othehr parameters are comparison our [8] Michèle Coutard, Thrombus versus Wall Biological Activities in
thrombus categories with the visualization categories is 81%. Experimental Aortic Aneurysms, Journal of Vascular Research,2009
For the evolution of the aortic diameter, we found no [9] Shin Matsuoka, Quantification of Thin-Section CT Lung Attenuation in
correlation between thrombus signals with the evolution of the Acute Pulmonary Embolism : Correlations with Arterial Blood Gas
aortic diameter in Small AAA (R < 0.3), but the parameters Levels and CT Angiography, American Roentgen Ray Society,
186:1272-1279, May 2006
were used. The methodologies to measure and the
normalization area with muscle signal will be discussed. We
cannot use thrombus signal alone as a parameter to predict the AUTHORS PROFILE
evolution of the aortic diameter. Relationship between flow
data, thrombus signal and biology findings will be studied. A. Suhendra is a Lecturer of Informatics Engineering, Industrial Engineering
Fakulty of Industrial engineering, Gunadarma university.
Currently, comparison of the blood flow velocity with C. M. Karyati, Graduate from Master Program in Information System,
3D/4D modeling (aspect laminar flow and turbulence, Gunadarma Unviversity, 1998. She is now a Ph.D-Student at Groupe
maximum speed, radial speed, and shear stress) with evolution Imagerie Médicale, Le2i, UMR CNRS 5158, Faculté de Médecine,
Université de Bourgogne, Dijon, France
of the maximum diameter was performed.
A Muslim, Graduate from Master Program in Information System,
Gunadarma Unviversity, 1997. He is a Ph.D-Student at Groupe Database
ACKNOWLEDGEMENTS Sistem Information et Image, Le2i, UMR CNRS 5158, Faculté de
Science et L’Enginer, Université de Bourgogne, Dijon, France
This research was conducted because of aid from the MRI and
A. B. Mutiara is a Professor of Computer Science at Faculty of Computer
Nuclear Medicine Department at the Centre Hospital Science and Information Technology, Gunadarma University
Universitaire (CHU) de Bocage in Dijon, France. More
specifically the authors want to thank Nicolas Abello who has
been so helpful in terms of procurement data. A.B.M. also
gratefully acknowledges financial support of the Gunadarma
Education Foundation during the research.
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ISSN 1947-5500
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