• Title/Summary/Keyword: Vessel wall imaging

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Advances in Fast Vessel-Wall Magnetic Resonance Imaging Using High-Density Coil Arrays

  • Yin, Xuetong;Li, Nan;Jia, Sen;Zhang, Xiaoliang;Li, Ye
    • Investigative Magnetic Resonance Imaging
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    • v.25 no.4
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    • pp.229-251
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    • 2021
  • Arteriosclerosis is the leading cause of stroke, with a fatality rate surpassing that of ischemic heart disease. High-resolution vessel wall magnetic resonance imaging is generally recognized as a non-invasive and panoramic method for the evaluation of arterial plaque; however, this method requires improved signal-to-noise ratio and scanning speed. Recent advances in high-density head and neck coil arrays are characterized by broad coverage, multiple channels, and closefitting designs. This review analyzes fast magnetic resonance imaging from the perspective of accelerated algorithms for vessel wall imaging and demonstrates the need for effective algorithms for signal acquisition using advanced radiofrequency system. We summarize different phased-array structures under various experimental objectives and equipment conditions, introduce current research results, and propose prospective research studies in the future.

Targeting the culprit: vessel wall magnetic resonance imaging for evaluating stroke

  • Kim, Seung Min;Ha, Sang Hee;Kwon, Hanim;Kim, Yeon Jung;Ahn, Sung Ho;Kim, Bum Joon
    • Annals of Clinical Neurophysiology
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    • v.23 no.1
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    • pp.17-28
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    • 2021
  • The pathogenesis of many strokes originates in the vessel wall. Despite this, most traditional imaging focuses on the vascular lumen. Vessel-wall magnetic resonance imaging (VWMRI) is useful for establishing the etiology of intracranial stenosis. It also provides information regarding atherosclerotic plaque composition and thus plaque vulnerability, which is an indication of its potential to cause a stroke. In this review we focus on the characteristics of VWMRI findings in various arteriopathies related to intracranial artery stenosis, and discuss the clinical implications of these findings.

Blood Vessel Strain Imaging Using Linear Array Transducer (선형 트랜스듀서를 이용한 혈관 변형률 영상법)

  • Ahn, Dong-Ki;Jeong, Mok-Kun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.3
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    • pp.880-890
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    • 2010
  • The intrasvascular ultrasound (IVUS) imaging technique is used to diagnose cerebrovascular diseases such as stroke. Recently, elasticity imaging methods have been investigated to diagnose blood clots attached to blood vessel intima. However, the IVUS imaging technique is an invasive method that requires a transducer to be inserted into blood vessel. In this paper, strain images are obtained of blood clots attached to blood vessel intima with data acquired from outside the blood vessel using a linear array transducer. In order to measure the displacement of blood vessel accurately, experimental data are acquired by steering ultrasound beams so that they can intersect the blood vessel wall at right angles. The acquired rf data are demodulated to the baseband. The resulting complex baseband signals are then processed by an autocorrelation algorithm to compute the blood vessel movement and thereby produce strain image. This proposed method is verified by experiments on a plastic blood vessel mimicking phantom. The efficacy of the proposed method was verified using a home-made blood vessel mimicking phantom. The blood vessel mimicking phantom was constructed by making a 6 mm diameter hollow cylinder inside it to simulate a blood vessel and adhering 2 mm thick soft plaque to the inner wall of the hollow cylinder. The RF data were acquired using a clinical ultrasound scanner (Accuvix XQ, Medison, Seoul. Korea) with a 7.5 MHz linear array transducer by steering ultrasound beams in steps of $1^{\circ}$ from $-40^{\circ}$ to $40^{\circ}$ for a total of 81 angles. Experimental results show that the plaque region near the blood vessel wall is softer than background tissue. Although the imaging region is restricted due to the limited range of angles for which scan lines are perpendicular to the wall, the feasibility of strain imaging is demonstrated.

High-Resolution Magnetic Resonance Imaging of Intracranial Vertebral Artery Dissecting Aneurysm for Planning of Endovascular Treatment

  • Chun, Dong Hyun;Kim, Sung Tae;Jeong, Young Gyun;Jeong, Hae Woong
    • Journal of Korean Neurosurgical Society
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    • v.58 no.2
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    • pp.155-158
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    • 2015
  • The equipment and techniques associated with magnetic resonance imaging (MRI) have rapidly evolved. The development of 3.0 Tesla MRI has enabled high-resolution imaging of the intracranial vessel wall. High-resolution MRI (HRMRI) can yield excellent visualization of both the arterial wall and lumen, thus facilitating the detection of the primary and secondary features of intracranial arterial dissection. In the present report, we describe the manner in which HRMRI affected our endovascular treatment planning strategy in 2 cases with unruptured intracranial vertebral artery dissection aneurysm. HRMRI provides further information about the vessel wall and the lumen of the unruptured intracranial vertebral artery dissecting aneurysm, which was treated by an endovascular approach in the 2 current cases.

Arterial Wall Imaging in Angiographically Occult Spontaneous Subarachnoid Hemorrhage : New Insight into the Usual Suspect

  • Yoon, Wonki;Kim, Jang Hun;Roh, Haewon;Kwon, Taek-Hyun
    • Journal of Korean Neurosurgical Society
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    • v.65 no.2
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    • pp.245-254
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    • 2022
  • Objective : The etiology of angiographically occult spontaneous subarachnoid hemorrhage (AOsSAH) is unclear. Three-dimensional (3D) high-resolution vessel wall magnetic resonance imaging (HVM) might be useful in detecting the hidden arterial wall angiopathy in patients with AOsSAH. We aimed to demonstrate the feasibility of HVM for detecting the arterial cause of AOsSAH. Methods : Patients, who were diagnosed with AOsSAH in the first evaluations and underwent HVM, were enrolled. Their clinical and radiologic data were retrospectively reviewed. Especially, focal enhancement of arterial wall on HVM and repetitive catheterized angiograms were precisely compared. Results : Among 251 patients with spontaneous SAH, 22 patients were diagnosed with AOsSAH in the first evaluations (8.76%). After excluding three patients who did not undergo 3D-HVM, 19 patients were enrolled and classified as convexal (n=2) or perimesencephalic (n=4), and diffuse (n=13) groups. In convexal and perimesencephalic groups, no focal enhancement on HVM and no positive findings on repetitive angiography were noted. In diffuse group, 10 patients showed focal enhancement of arterial wall on HVM (10/13, 76.9%). Repeated angiography with 3D reconstruction revealed four patients of angiographically positive causative arteriopathy and possible lesion in one case in the concordant location of intramural enhancement on 3D-HVM (5/10, 50%). Three of them were treated with endovascular stent insertion. All patients, except one, recovered with good clinical outcome (3-month modified Rankin score, 0 and 1). Conclusion : 3D-HVM was useful in detecting hidden true arteriopathy in AOsSAH. It may provide new insights into the etiologic investigation of AOsSAH by proving information about the arterial wall status.

Development of a High-Speed Endoscopic OCT System and Its Application to Three-Dimensional Intravascular Imaging in Vivo (고속 내시경적 OFDI 시스템 개발과 이를 이용한 3차원 생체 혈관 내부 이미징)

  • Cho, Han Saem;Jang, Sun-Joo;Oh, Wang-Yuhl
    • Korean Journal of Optics and Photonics
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    • v.25 no.2
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    • pp.67-71
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    • 2014
  • Intravascular optical coherence tomography (OCT) enables imaging of the three-dimensional (3D) microstructure of a blood vessel wall. While 3D vascular visualization provides detailed information of the vessel wall and intraluminal structures, a longitudinal imaging pitch that is several times bigger than the imaging resolution of the system has limited true high-resolution 3D imaging. In this paper we demonstrate high-speed intravascular OCT in vivo, acquiring images at a rate of 350 frames per second. A 47-mm-long rabbit aorta was imaged in 3.7 seconds, after a short flush with contrast agent. The longitudinal imaging pitch was 34 micrometers, comparable to the transverse imaging resolution of the system. Three-dimensional volume rendering showed greatly enhanced visualization of tissue microstructure and stent struts, relative to what is provided by conventional intravascular imaging speeds.

Reversible Cerebral Vasoconstriction Syndrome Presenting as Transient Vessel Wall Enhancement on Contrast-Enhanced Fluid-Attenuated Inversion Recovery Images: A Case Report and Literature Review (조영증강 유체감쇠반전회복기법 영상에서 일과성 혈관 벽 조영증강으로 나타나는 가역성 대뇌 혈관 수축 증후군: 증례 보고 및 문헌 고찰)

  • Sun Ah Heo;Eun Soo Kim;Yul Lee
    • Journal of the Korean Society of Radiology
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    • v.81 no.5
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    • pp.1239-1245
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    • 2020
  • Reversible cerebral vasoconstriction syndrome (RCVS) is a clinical and radiological syndrome with primary features that include hyperacute onset of severe headache and segmental vasoconstriction of the cerebral arteries, which resolve within 3 months. Vessel wall enhancement has been reported in some cases of RCVS; however, its pathophysiological and diagnostic implications remain unclear. We review a case of RCVS in a patient with transient vessel wall enhancement on contrast-enhanced fluid-attenuated inversion recovery images, focusing on the pathophysiological and diagnostic implications.

In Vivo Visualization of Flow in Xylem Vessels of a Bamboo Using X-ray Micro-imaging Technique (X-ray 미세영상기법을 이용한 식물 목질부 내부 수액 유동의 계측)

  • Kim, Yang-Min;Lee, Sang-Joon
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1693-1696
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    • 2004
  • Synchrotron X-ray micro-imaging technique was employed to monitor non-invasively the refilling process of water inside the xylem vessels in bamboo leaves. The consecutive phase-contrast X-ray images clearly show both plant anatomy and the transport of water inside the xylem vessels. Traces of water-rise, vapor bubbles and variations of contact angle between the water front and the xylem wall were measured in real time. During the refilling process, air bubbles are removed when the rising water front halts at a vessel end for a while. Subsequently, it starts rising again at a higher velocity than the normal refilling speed. Repeated cavitation seems to deteriorate the refilling ability in xylem vessels. In dark environment, the water refilling process in xylem vessels is facilitated more effectively than in bright illuminated conditions. Finally, X-ray micro-imaging was famed to be a powerful, high resolution, real time imaging tool to investigate the water refilling process in xylem vessels.

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Diagnosis Atherosclerosis Model Using Radiomics Approach in Carotid Vessel MRI (경동맥 혈관 MRI에서 라디오믹스를 이용한 동맥경화증 진단 모델)

  • Kim, Jong-hun;Park, Hyunjin
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2022.10a
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    • pp.289-290
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    • 2022
  • Arteriosclerosis is a disease in which the carotid vessel wall becomes thick, and it is important to monitor the thickness of the vessel wall for diagnosis. In this study, we propose a model for extracting 324 radiomics features from carotid MRI images and diagnosing arteriosclerosis using machine learning techniques. We learned a total of four classification models: logistic regression, support vector machine, random forest, and XGBoost through radiomics features. XGBoost model, which showed the highest performance in 5-fold cross-validation, shows the results of accuracy 0.9023, sensitivity 0.9517, specificity 0.8035, AUC 0.8776.

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Increased Wall Enhancement Extent Representing Higher Rupture Risk of Unruptured Intracranial Aneurysms

  • Jiang, Yeqing;Xu, Feng;Huang, Lei;Lu, Gang;Ge, Liang;Wan, Hailin;Geng, Daoying;Zhang, Xiaolong
    • Journal of Korean Neurosurgical Society
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    • v.64 no.2
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    • pp.189-197
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    • 2021
  • Objective : This study aims to investigate the relationship between aneurysm wall enhancement and clinical rupture risks based on the magnetic resonance vessel wall imaging (MR-VWI) quantitative methods. Methods : One hundred and eight patients with 127 unruptured aneurysms were prospectively enrolled from Feburary 2016 to October 2017. Aneurysms were divided into high risk (≥10) and intermediate-low risk group (<10) according to the PHASES (Population, Hypertension, Age, Size of aneurysm, Earlier SAH history from another aneurysm, Site of aneurysm) scores. Clinical risk factors, aneurysm morphology, and wall enhancement index (WEI) calculated using 3D MR-VWI were analyzed and compared. Results : In comparison of high-risk and intermediated-low risk groups, univariate analysis showed that neck width (4.5±3.3 mm vs. 3.4±1.7 mm, p=0.002), the presence of wall enhancement (100.0% vs. 62.9%, p<0.001), and WEI (1.6±0.6 vs. 0.8±0.8, p<0.001) were significantly associated with high rupture risk. Multivariate regression analysis revealed that WEI was the most important factor in predicting high rupture risk (odds ratio, 2.6; 95% confidence interval, 1.4-4.9; p=0.002). The receiver operating characteristic (ROC) curve analysis can efficiently differentiate higher risk aneurysms (area under the curve, 0.780; p<0.001) which have a reliable WEI cutoff value (1.04; sensitivity, 0.833; specificity, 0.67) predictive of high rupture risk. Conclusion : Aneurysms with higher rupture risk based on PHASES score demonstrate increased neck width, wall enhancement, and the enhancement intensity. Higher WEI in unruptured aneurysms has a predictive value for increased rupture risk.