In vivo real-time microangiography of the liver in mice using synchrotron radiation

Kobayashi, Shōgo; Hori, Masatoshi; Dono, Keizo; Nagano, Hiroaki; Umeshita, Koji; Nakamori, Shoji; Sakon, Masato; Osuga, Keigo; Umetani, Keiji; Murakami, Takamichi; Nakamura, Hajime; Monden, Morito

doi:10.1016/j.jhep.2003.11.029

Cited by 23 publications

(20 citation statements)

References 16 publications

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“…Microangiography using synchrotron radiation has recently been applied to a range of vascular beds (27), including the liver (14), lungs (25,26), brain (13, 18 -20, 30), and heart (12). One of the major the strengths of the technique is that there is no geometric magnification of vessels.…”

Section: Discussionmentioning

confidence: 99%

Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation

Eppel¹,

Jacono²,

Shirai³

et al. 2009

American Journal of Physiology-Renal Physiology

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Eppel GA, Jacono DL, Shirai M, Umetani K, Evans RG, Pearson JT. Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation. Am J Physiol Renal Physiol 296: F1023-F1031, 2009. First published March 4, 2009 doi:10.1152/ajprenal.90499.2008.-We have developed a new method for contrast microangiography of the rat renal circulation using synchrotron radiation. The method was applied to determine responses of the renal arterial vasculature to angiotensin II and electrical stimulation of the renal nerves (RNS). Iodinated contrast agent was administered directly into the renal artery of pentobarbital-anesthetized rats before and during 1) intravenous infusion of angiotensin II (1.6 g ⅐ kg Ϫ1 ⅐ min Ϫ1 ) or 2) its vehicle, or 3) RNS at 2 Hz. Images were obtained at 30 Hz, before and during these treatments, and vascular caliber was determined by use of a newly developed algorithm described herein. Up to four levels of branching could be observed simultaneously along the arterial tree, comprising vessels with resting diameter of 28 -400 m. Vessel diameter was not significantly altered by vehicle infusion (ϩ3.1 Ϯ 3.5% change) but was significantly reduced by angiotensin II (Ϫ24.3 Ϯ 3.4%) and RNS (Ϫ17.1 Ϯ 3.8%). Angiotensin II-induced vasoconstriction was independent of vessel size, but RNS-induced vasoconstriction was greatest in vessels with a resting caliber of 100 -200 m and least in vessels with a resting caliber 40 -100 m. In conclusion, the method we describe herein provides a new approach for assessing responses of the renal arterial circulation to vasoactive factors along several orders of branching.angiography; angiotensin II; vascular caliber; kidney circulation; renal nerves RENAL VASCULAR TONE IS A CRITICAL controller of renal perfusion, glomerular filtration rate, and tubular function (21) and thus long-term regulation of body fluid homeostasis (9). Many available methodologies allow quantification of changes in the caliber of resistance vessels in vivo, but all have important limitations. For example, vascular casting techniques allow quantification of vascular caliber at multiple points along the renal vascular tree, potentially allowing analysis of regulation of blood flow within networks of blood vessels in the kidney (4, 5). But an important disadvantage of this approach is that measurements can only be made at a single time point so that the effects of vasoactive factors can only be inferred from cross-sectional comparisons between blood vessels in different animals. Real-time analysis of vascular caliber (17) and capillary blood velocity (33) within the kidney has been achieved with intravital microscopy, but currently the measurements derived from such techniques are limited to single points along an identified blood vessel. Magnetic resonance imaging and X-ray microtomographic techniques currently lack the spatial and/or temporal resolution required for real-time analysis of resistance vessel caliber in the kidney in vivo (1).Herein we present a new approach that overcom...

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Section: Discussionmentioning

confidence: 99%

Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation

Eppel¹,

Jacono²,

Shirai³

et al. 2009

American Journal of Physiology-Renal Physiology

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“…The final subtracted image not only eliminates background structures but also eliminates uneven iodine distribution and magnifies the contrast between vessel and background. Indeed, such image enhancement allows visualization of vessels Ͻ50 m, and as small as 20 -30 m, within the microvasculature of tumors (in vitro), exposed heart (28), liver (12), and brain (11,29) of experimental animals.…”

Section: Discussionmentioning

confidence: 99%

Imaging of the pulmonary circulation in the closed-chest rat using synchrotron radiation microangiography

Schwenke

Pearson²,

Umetani³

et al. 2007

Journal of Applied Physiology

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Schwenke DO, Pearson JT, Umetani K, Kangawa K, Shirai M. Imaging of the pulmonary circulation in the closed-chest rat using synchrotron radiation microangiography. J Appl Physiol 102: [787][788][789][790][791][792][793] 2007. First published October 12, 2006; doi:10.1152/japplphysiol.00596.2006.-Structural changes of the pulmonary circulation during the pathogenesis of pulmonary arterial hypertension remain to be fully elucidated. Although angiography has been used for visualizing the pulmonary circulation, conventional angiography systems have considerable limitations for visualizing small microvessels (diameters Ͻ 200 m), particularly within a closed-chest animal model. In this study we assess the effectiveness of monochromatic synchrotron radiation (SR) for microangiography of the pulmonary circulation in the intact-chest rat. Male adult Sprague-Dawley rats were anesthetized, and a catheter was positioned within the right ventricle, for administering iodinated contrast agent (Iomeron 350). Subsequently, microangiography of pulmonary arterial branches within the left lung was performed using monochromatic SR. Additionally, we assessed dynamic changes in vessel diameter during acute hypoxic (10% and 8% O 2 for 4 min each) pulmonary vasoconstriction (HPV). Using SR we were able to visualize pulmonary microvessels with a diameter of Ͻ100 m (the 4th generation of branching from the left axial artery). Acute hypoxia caused a significant decrease in the diameter of all vessels less than 500 m. The greatest degree of pulmonary vasoconstriction was observed in vessels with a diameter between 200 and 300 m. These results demonstrate the effectiveness of SR for visualizing pulmonary vessels in a closed-chest rat model and for assessing dynamic changes associated with HPV. More importantly, these observations implicate SR as an effective tool in future research for assessing gross structural changes associated with the pathogenesis of pulmonary arterial hypertension. pulmonary microvessels; hypoxia; intact chest STRUCTURAL AND FUNCTIONAL changes of the pulmonary circulation, particularly during the pathogenesis of pulmonary arterial hypertension (PAH), remain to be fully elucidated. Specifically, the small peripheral pulmonary arteries (Ͻ500 m) are believed to be most susceptible to structural changes during, for example, chronic exposure to hypoxia (1,6,7,15,19,32).To date, most small-animal studies that have described the anatomic geometry of the pulmonary circulation have been limited to the use of in vitro or ex vivo preparations. While such data have aided our understanding concerning the pulmonary microcirculation, such invasive procedures ultimately disrupt the natural physiological milieu of the lung. Ideally, a technique of visualizing the pulmonary circulation within a closed-chest model, i.e., under intact neurohumoral regulation, is required to fully understand the structural and functional properties of the microcirculation in the normal lung as well as understand the dynamic changes that occur in pathologic...

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“…The drive for higher spatial and temporal resolution to capture rapid physiologic changes has led to the development of the micro power contrast injector described in this paper. Prior work in mice and rats [2,[13][14][15][16][17][18][19][20][21] has not fully optimized the methods for small animals. For example, previous images were acquired asynchronous with cardiac or ventilatory cycles, resulting in limited precision in measuring physiologic changes and significant subtraction artifacts.…”

Section: Introductionmentioning

confidence: 99%

A High-Precision Contrast Injector for Small Animal X-Ray Digital Subtraction Angiography

Lin

Ning

Badea

et al. 2008

IEEE Trans. Biomed. Eng.

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The availability of genetically altered animal models of human disease for basic research has generated great interest in new imaging methodologies. Digital subtraction angiography (DSA) offers an appealing approach to functional imaging in small animals because of the high spatial and temporal resolution, and the ability to visualize and measure blood flow. The micro-injector described here meets crucial performance parameters to ensure optimal vessel enhancement without significantly increasing the total blood volume or producing overlap of enhanced structures. The micro-injector can inject small, reproducible volumes of contrast agent at high flow rates with computer-controlled timing synchronized to cardio-pulmonary activity. Iterative bench-top and live animal experiments with both rat and mouse have been conducted to evaluate the performance of this computer-controlled micro-injector, a first demonstration of a new device designed explicitly for the unique requirements of DSA in small animals. Injection protocols were optimized and screened for potential physiological impact. For the optimized protocols, we found that changes in the time-density curves for representative regions of interest in the thorax were due primarily to physiological changes, independent of micro-injector parameters.

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In vivo real-time microangiography of the liver in mice using synchrotron radiation

Cited by 23 publications

References 16 publications

Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation

Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation

Imaging of the pulmonary circulation in the closed-chest rat using synchrotron radiation microangiography

A High-Precision Contrast Injector for Small Animal X-Ray Digital Subtraction Angiography

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