3D Cardiac microvessels embolization imaging based on X-ray phase contrast imaging
BioMedical Engineering OnLine
3D Cardiac microvessels embolization imaging based on X-ray phase contrast imaging
Lu Zhang 0
Ke Wang 2
Fei Zheng 1
Xia Li 0
Shuqian Luo 0
0 School of Biomedical engineering, Capital Medical University , Beijing , P.R. China
1 Beijing Friendship Hospital, Capital Medical University , Beijing , P.R. China
2 Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University , Beijing , P.R. China
Background: The treatment of microcirculatory impairment will have great impact if it can be applied to myocardial infarction (MI) patients. The problem is how to study these tiny structures and microphenomenon in heart. Methods: We investigated the visualization of cardiac microvessels embolization by the mean of X-ray phase contrast imaging (XPCI), which is a recently emerged imaging technique. Using the information of X-ray phase shift, it is sensitive to weak absorbing materials. Two MI SD rats were used as the microvessel embolization samples. MI was surgically induced by ligating left anterior descending artery. Imaging was performed 24 hours post-infarct, with barium sulfate as contrast agent. Results: The coronary arteries were visualized with smooth walls and clear edges. The ligated vessels, with the diameter of about three hundred microns, can be clearly distinguished and there were no distal blood flow downstream from these branches. The results indicate that phase contrast imaging can directly demonstrate the distribution of microvessels, and estimate the area of MI. The infarct location was in good agreement with pathological analyses of the models. Conclusions: The advantage of our method is directly observing and evaluating microvessel embolization which simplifies the procedure of diagnoses. Moreover, it is helpful for predicting the prognosis in MI and judging if angiogenesis happens.
X-ray phase contrast imaging (XPCI); Microvessel embolization imaging; Myocardial infarction (MI)
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The occlusion of coronary artery is the most common cause of Myocardial Infarction
(MI) [1]. When MI happens, diminished blood supply of one or some coronary arteries
will lead to myocardial ischemia, which will result in myocardial cell damage or death.
To date, MI is still a worldwide disease with high morbidity and mortality. The main
reason of that might be because of the link between the occurrence of MI and
hyperlipidemia, diabetes mellitus, hypertension, smoking, obesity, lack of exercise and job
stress. People, more or less, suffer from these risk factors [2].
Clinically, reperfusion has proven to be the vital procedure to improve the survival
rate of MI patients. Recent studies have shown that even though after a rapid
reopening of the previously obstructed coronary artery, some distal microvessels remain
ischemia, which is called no-reflow phenomenon [3,4]. This abstruse, but important
phenomenon is frequently happened during reperfusion of myocardial infarction. It
has close relationship with patients chest pain, hemodynamic deterioration, ST-segment
elevation, infarct extensions, ventricular arrhythmias, early congestive heart failure, and
even cardiac rupture [5,6]. Therefore, the reperfusion of microvessels is currently of
significant interest. The treatment of microcirculatory impairment will have greater impact if
it can be applied to MI patients. The problem is how to study these tiny structures and
microphenomenon in heart.
With the development of imaging technique, contrast echocardiography (MCE),
positron emission tomography (PET), and contrast-enhanced magnetic resonance imaging
(MRI) are becoming the most effective method for microvascular assessment. The area
of ischemia can be defined through those methods. But the use of these techniques
have been limited on imaging individual microvessels [7-9]. For the study of myocardial
microcirculation, structure and function have the same importance. However, there are
no ideal methods to realize cardiac microvessel imaging without destroying the original
complete heart. Conventional histological studies only provide an accurate view of
microvessels on cross-sectional specimens in two-dimension (2D). However, in order to
study the cardiac microvessels embolization, three-dimemsional (3D) morphology of
the blood vessel system has to be precisely determined. The 3D reconstruction of
vascular network via a serious of sectioning is very complicated and time-consuming.
Confocal laser scanning microscope (CLSM) has a high imaging resolution as well as 3D
imaging ability. Unfortunately, the sample size should be very small and thin [10]. It is
not suitable for a whole rat heart imaging.
X-ray Phase contrast imaing (XPCI) became a research focus about some decades
ago with the awareness of its high spatial resolution and contrast on imaging soft
tissues [11,12]. It is capable for detecting the direction deviation when X-rays travel
through one object. Compared with clinical used X-ray me (...truncated)