NIH HL081171, NIH HL080203 지원

<ol>
	<li>Bolar, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+of+regional+pulmonary+blood+flow+using+ASL-FAIRER.">Quantification of regional pulmonary blood flow using ASL-FAIRER.</a> Magn Reson Med. 55, 1308-1317 (2006).</li><li>Henderson, A. C., Prisk, G. K., Levin, D. L., Hopkins, S. R., Buxton, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterizing+pulmonary+blood+flow+distribution+measured+using+arterial+spin+labeling.">Characterizing pulmonary blood flow distribution measured using arterial spin labeling.</a> NMR Biomed. 22, 1025-1035 (2009).</li><li>Theilmann, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+MRI+measurement+of+lung+density+must+account+for+the+change+in+T(2)+(*)+with+lung+inflation.">Quantitative MRI measurement of lung density must account for the change in T(2) (*) with lung inflation.</a> J Magn Reson Imaging. 30, 527-534 (2009).</li><li>Hopkins, S. R., Garg, J., Bolar, D. S., Balouch, J., Levin, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulmonary+blood+flow+heterogeneity+during+hypoxia+and+high-altitude+pulmonary+edema.">Pulmonary blood flow heterogeneity during hypoxia and high-altitude pulmonary edema.</a> Am J Respir Crit Care Med. 171, 83-87 (2005).</li><li>Miller, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standardisation+of+spirometry.">Standardisation of spirometry.</a> Eur Respir J. 26, 319-338 (2005).</li><li>Hopkins, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vertical+gradients+in+regional+lung+density+and+perfusion+in+the+supine+human+lung:+the+Slinky+effect.">Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effect.</a> J Appl Physiol. 103, 240-248 (2007).</li><li>Arai, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypoxic+pulmonary+vasoconstriction+does+not+contribute+to+pulmonary+blood+flow+heterogeneity+in+normoxia+in+normal+supine+humans.">Hypoxic pulmonary vasoconstriction does not contribute to pulmonary blood flow heterogeneity in normoxia in normal supine humans.</a> J Appl Physiol. 106, 1057-1064 (2009).</li><li>Dawson, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+pulmonary+vasomotion+in+physiology+of+the+lung.">Role of pulmonary vasomotion in physiology of the lung.</a> Physiol Rev. 64, 544-616 (1984).</li><li>Prisk, G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulmonary+perfusion+in+the+prone+and+supine+postures+in+the+normal+human+lung.">Pulmonary perfusion in the prone and supine postures in the normal human lung.</a> J Appl Physiol. 103, 883-894 (2007).</li><li>Henderson, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Steep+head-down+tilt+has+persisting+effects+on+the+distribution+of+pulmonary+blood+flow.">Steep head-down tilt has persisting effects on the distribution of pulmonary blood flow.</a> J Appl Physiol. 101, 583-589 (2006).</li><li>Levin, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+age+on+pulmonary+perfusion+heterogeneity+measured+by+magnetic+resonance+imaging.">Effects of age on pulmonary perfusion heterogeneity measured by magnetic resonance imaging.</a> J Appl Physiol. 102, 2064-2070 (2007).</li><li>Wasserman, K. H., Sue, D., Casaburi, R., Whipp, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calculations,+Fomulae,+and+Examples+(Appendix+C).">Calculations, Fomulae, and Examples (Appendix C).</a> Principles of Exercise Testing and Interpretation. , (1999).</li></ol>

관심 없음 충돌 선언하지 않습니다.

이 방법은 MR 검사 환경에서 기본적인 생리 기술을 사용하여 폐동맥 혈류의 공간적 분포에 대한 영감을 산소 농도의 효과 측정이 가능합니다. 폐의 양적 프로톤 이미징와 함께 생리 기법의 사용은 비교적 쉽게 구현됩니다. 좋은 품질 테스트를 보장하기 위해 가장 중요한 단계는 올바른 폐 볼륨에서와 이미지 시퀀스로 synchrony에서 숨을 - 저장할 주제를 훈련합니다. ASL과 프로?...

<table border="1"><tbody><tr><th> 장비 </th><th> 회사 </th><th> 모델 </th></tr><tr><td> MRI </td><td> GE </td><td> 1.5 T GE HDx E​​XICITE twinspeed 스캐너 </td></tr><tr><td> 신진 대사 장바구니 </td><td> ParvoMedics </td><td> TrueOne 2400 </td></tr><tr><td> 펄스 산소 농도계 </td><td> Nonin </td><td> FOR 7500 </td></tr><tr><td> Spirometer </td><td> 의료 기술 앤도버 </td><td> EasyOne의 diagonostic의 Spirometer </td></tr><tr><td> 마스크 </td><td> 한스 &amp; 루돌프 </td><td> 7400 시리즈 오로 - 네이절 마스크, 소형, 중형 및 대형 </td></tr><tr><td> 밸브 </td><td> 한스 &amp; 루돌프 </td><td> 양방향이 아닌 rebreathing 밸브 T - 모양 ™ 구성, 2600 중간. 대형 2,700 </td></tr><tr><td> 헤드 세트 </td><td> 한스 &amp; 루돌프 </td><td> 헤드 캡 (어른 사이즈), 스트랩 및 잠금 클립. </td></tr><tr><td> 공압 방향 제어 밸브 및 제어기 </td><td> 한스 &amp; 루돌프 </td><td> 싱글 피스톤 슬라이딩 타입 ™ 밸브와 컨트롤러 4285A </td></tr><tr><td> 비 Diffusing 가스 수집 가방 </td><td> 한스 &amp; 루돌프 </td><td> 6100 (100리터). </td></tr><tr><td> 튜브 </td><td> VacuMed </td><td> 클린 - 보르 튜브 108 &quot;, 1-3/8&quot;OD 부품 </td></tr><tr><td> 유령 </td><td> 맨토 </td><td> 브레스트 임플란트 라운드, 250cc </td></tr><tr><td> matlab </td><td> MathWorks </td><td></td></tr></tbody></table>

magnetic resonance imaging quantification of pulmonary perfusion using calibrated arterial spin labeling

이것은 normoxia 동안 건강한 과목 hypoxia (F I O 2 = 0.125), 그리고 hyperoxia ((O 2, 분수 (F I O 2) = 0.21 영감을)에서 폐동맥 혈류의 공간적 분포를 측정할 수 MR 이미징 방법을 보여줍니다 F I O 2 = 1.00). 또한, 피사체의 생리적 반응은 MR 검사 환경에서 모니터링하고 있습니다. MR 이미지는 기능 잔류 용량에서 우측 폐의 화살 슬라이스에서 숨을 보류 중 1.5 T MRI GE 스캐너를 획득했다. 동맥 스핀 라벨링 순서 (ASL - 공정한)이 지역 양성자 (예 : H 2 O)를 계량하는 데 사용된 폐 혈액 흐름 1,2 및 다중 에코 빠른 기울기 에코 (mGRE) 순서 3의 공간적 분포를 측정하는 데 사용되었다 각 voxel (g 폐 조직마다 분당 밀리리터 혈액)에 대한 밀도화된 재관류의 부량를 허용 밀도. 밸브와 안면 스위칭 공기는 2 방식이 아닌 rebreathing 밸브가 장착된와 다른 산소 농도는 영감을 가스 튜브를 통해 MR 스캐너의 주제 도입되었습니다. 신진 대사 카트 날숨 튜브를 통해 날숨 가스를 수집했습니다. 혼합 날숨 O 2, CO 2 농도, 산소 소비, 이산화탄소 생산, 호흡 교환 비율, 호흡 주파수 및 갯벌 볼륨이 측정되었다. 심장 박동과 산소 포화도는 펄스 oximetry을 사용하여 모니터링할되었습니다. 일반 과목에서 얻은 데이터는 예상대로, 심장 박동이 normoxia (51) 또는 hyperoxia (50) 동안보다 hypoxia (60 BPM)에 높은되었고 동맥 산소 포화도 (SpO 2) 86%에 hypoxia 동안 감소 되었음 것으로 나타났다. 환기, hypoxia 동안 7.04 L / 분 normoxia 동안, 그리고 hyperoxia 동안 6.64 L / 분 8.31 L / 분 BTPS했습니다 의미합니다. 조수 볼륨 normoxia 동안 hypoxia, 0.69 L 동안 0.76 L, 그리고 hyperoxia 동안 0.67 L되었습니다. 대표 계량 ASL 데이터는 평균 밀도 표준 재관류가 8.26 ML / normoxia 동안 분 / g과 8.46 hyperoxia 동안 ML / 분 / G, 각각 hypoxia 동안 8.86 ML / 분 / G 보였다. 동안이 주제에서는, 상대 분산 4, 글로벌 이질의 인덱스 (normoxia 동안 hypoxia 동안 1.07, 0.85, 그리고 hyperoxia 중 0.87) hypoxia 증가했던 프랙탈 차원 (DS), 혈관 분기 구조를 반영 이질의 다른 인덱스, (normoxia 중 hypoxia 동안 1.24, 1.26, 그리고 hyperoxia 중 1.26) 변경되었습니다. 개요. 이 프로토콜은 동맥 스핀 라벨링 (ASL)로 알려진 자기 공명 이미징 기술을 사용하여 normoxia, hypoxia, 그리고 hyperoxia의 조건 noninvasively 폐의 재관류의 분포를 측정하기위한 데이터의 수집을 설명합니다. 이유 : MR 기법을 사용하여 폐 혈액 흐름과 폐 프로톤 밀도의 측정이 높은 공간 해상도 계량 수있는 이미지와 여러 생리적 조건 하에서 반복 측정을 수행할 수있는 기능을 제공합니다. 인간 연구에서 PET, SPECT, 그리고 중부 표준시은 일반적으로 다른 기법으로 사용됩니다. 그러나 이러한 기술은 이온화 방사선에 노출을 포함하고, 따라서 인간의 과목에서 반복 측정에 적합하지 않습니다.

Watch this Scientific Journal Video about Magnetic Resonance Imaging Quantification of Pulmonary Perfusion using Calibrated Arterial Spin Labeling at JoVE.com

Magnetic Resonance Imaging Quantification of Pulmonary Perfusion using Calibrated Arterial Spin Labeling

세 가지 다른 영감 산소 농도에 노출이 경우에 생리 조건에 따라 다양한 폐동맥 혈류의 분포를 연구 MR 이미징 방법 : hypoxia, normoxia, 그리고 hyperoxia가 설명되어 있습니다. 이 기술은 MR 검사 환경에서 인간의 폐 생리학 연구 기술을 활용합니다.

조정 아티 스핀 라벨을 사용하여 폐 관류의 자기 공명 이미징 부량

This demonstrates a MR imaging method to measure the spatial distribution of pulmonary blood flow in healthy subjects 
during normoxia (inspired O2, ...

magnetic-resonance-imaging-quantification-pulmonary-perfusion-using

Research

JoVE Journal

Medicine

13.4K 조회수.  University of California San Diego - UCSD. 세 가지 다른 영감 산소 농도에 노출이 경우에 생리 조건에 따라 다양한 폐동맥 혈류의 분포를 연구 MR 이미징 방법 : hypoxia, normoxia, 그리고 hyperoxia가 설명되어 있습니다. 이 기술은 MR 검사 환경에서 인간의 폐 생리학 연구 기술을 활용합니다.

비디오: Magnetic Resonance Imaging Quantification of Pulmonary Perfusion using Calibrated Arterial Spin Labeling

Magnetic Resonance Derived Myocardial Strain Assessment Using Feature Tracking

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF. Current technologies for CMR are time consuming and difficult to implement in clinical practice. Feature tracking is a technology that can lead to more automization and robustness of quantitative analysis of medical images with less time consumption than comparable methods.
Methods: An automatic or manual input in a single phase serves as an initialization from which the system starts to track the displacement of individual patterns representing anatomical structures over time. The specialty of this method is that the images do not need to be manipulated in any way beforehand like e.g. tagging of CMR images.
Results: The method is very well suited for tracking muscular tissue and with this allowing quantitative elaboration of myocardium and also blood flow.
Conclusions: This new method offers a robust and time saving procedure to quantify myocardial tissue and blood with displacement, velocity and deformation parameters on regular sequences of CMR imaging. It therefore can be implemented in clinical practice.

An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF.

기능 추적을 사용하여 자기 공명이 유래 심근 스트레인 평가

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that ...

연구

의학

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease

Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of living systems. Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multi-faceted pathology. The goal of this protocol is to characterize this pathology using qMRI methods. The MRI acquisition protocol begins with localizer images (used to locate the position of the body and tissue of interest within the MRI system), quality control measurements of relevant magnetic field distributions, and structural imaging for general anatomical characterization. The qMRI portion of the protocol includes measurements of the longitudinal and transverse relaxation time constants (T1 and T2, respectively). Also acquired are diffusion-tensor MRI data, in which water diffusivity is measured and used to infer pathological processes such as edema. Quantitative magnetization transfer imaging is used to characterize the relative tissue content of macromolecular and free water protons. Lastly, fat-water MRI methods are used to characterize fibro-adipose tissue replacement of muscle. In addition to describing the data acquisition and analysis procedures, this paper also discusses the potential problems associated with these methods, the analysis and interpretation of the data, MRI safety, and strategies for artifact reduction and protocol optimization.

Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multi-faceted pathology. The goal of this protocol is to characterize this pathology using non-invasive magnetic resonance imaging methods.

골격근 질환의 정량적 자기 공명 영상

Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of ...

Simultaneous PET/MRI Imaging During Mouse Cerebral Hypoxia-ischemia

Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics disturbance in affected cells. Diffusion weighted magnetic resonance imaging (MRI) identifies regions that are damaged, potentially irreversibly, by hypoxia-ischemia. Alterations in glucose utilization in the affected tissue may be detectable by positron emission tomography (PET) imaging of 2-deoxy-2-(18F)fluoro-&#7429;-glucose ([18F]FDG) uptake. Due to the rapid and variable nature of injury in this animal model, acquisition of both modes of data must be performed simultaneously in order to meaningfully correlate PET and MRI data. In addition, inter-animal variability in the hypoxic-ischemic injury due to vascular differences limits the ability to analyze multi-modal data and observe changes to a group-wise approach if data is not acquired simultaneously in individual subjects. The method presented here allows one to acquire both diffusion-weighted MRI and [18F]FDG uptake data in the same animal before, during, and after the hypoxic challenge in order to interrogate immediate physiological changes.

The method presented here uses simultaneous positron emission tomography and magnetic resonance imaging. In the cerebral hypoxia-ischemia model, dynamic changes in diffusion and glucose metabolism occur during and after injury. The evolving and irreproducible damage in this model necessitates simultaneous acquisition if meaningful multi-modal imaging data are to be acquired.

마우스 대뇌 저산소증 - 허혈 동안 동시 PET / MRI 영상

Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics ...

Hemodynamic Characterization of Rodent Models of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle proliferation and obliteration of pulmonary arterioles. This in turn results in right ventricular (RV) failure, with significant morbidity and mortality. Rodent models of PAH, in the mouse and the rat, are important for understanding the pathophysiology underlying this rare disease. Notably, different models of PAH may be associated with different degrees of pulmonary hypertension, RV hypertrophy and RV failure. Therefore, a complete hemodynamic characterization of mice and rats with PAH is critical in determining the effects of drugs or genetic modifications on the disease. 
Here we demonstrate standard procedures for assessment of right ventricular function and hemodynamics in both rat and mouse PAH models. Echocardiography is useful in determining RV function in rats, although obtaining standard views of the right ventricle is challenging in the awake mouse. Access for right heart catheterization is obtained by the internal jugular vein in closed-chest mice and rats. Pressures can be measured using polyethylene tubing with a fluid pressure transducer or a miniature micromanometer pressure catheter. Pressure-volume loop analysis can be performed in the open chest. After obtaining hemodynamics, the rodent is euthanized. The heart can be dissected to separate the RV free wall from the left ventricle (LV) and septum, allowing an assessment of RV hypertrophy using the Fulton index (RV/(LV+S)). Then samples can be harvested from the heart, lungs and other tissues as needed.

Pulmonary arterial hypertension (PAH) is a disease of pulmonary arterioles that leads to their obliteration and the development of right ventricular failure. Rodent models of PAH are critical in understanding the pathophysiology of PAH. Here we demonstrate hemodynamic characterization, with right heart catheterization and echocardiography, in the mouse and rat.

폐동맥 고혈압의 설치류 모델의 혈역학 특성

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle ...

Cardiac Magnetic Resonance Imaging at 7 Tesla

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher magnetic field strengths and potentially provides improved signal contrast and spatial resolution. While promising results have been achieved, ultra-high field CMR is challenging due to energy deposition constraints and physical phenomena such as transmission field non-uniformities and magnetic field inhomogeneities. In addition, the magneto-hydrodynamic effect renders the synchronization of the data acquisition with the cardiac motion difficult. The challenges are currently addressed by explorations into novel magnetic resonance technology. If all impediments can be overcome, ultra-high field CMR may generate new opportunities for functional CMR, myocardial tissue characterization, microstructure imaging or metabolic imaging. Recognizing this potential, we show that multi-channel radio frequency (RF) coil technology tailored for CMR at 7 Tesla together with higher order B0 shimming and a backup signal for cardiac triggering facilitates high fidelity functional CMR. With the proposed setup, cardiac chamber quantification can be accomplished in examination times similar to those achieved at lower field strengths. To share this experience and to support the dissemination of this expertise, this work describes our setup and protocol tailored for functional CMR at 7 Tesla.

The sensitivity gain inherent to ultrahigh field magnetic resonance holds promise for high spatial resolution imaging of the heart. Here, we describe a protocol customized for functional cardiovascular magnetic resonance (CMR) at 7 Tesla using an advanced multi-channel radio-frequency coil, magnetic field shimming and a triggering concept.

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher ...

Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous studies have shown that abnormal blood flow may be associated with systemic vascular risk. Thus, PC-MRI can facilitate the translation of data obtained from animal models of cardiovascular diseases to pertinent clinical investigations. In this report, we describe the procedure for measuring blood flow in the common carotid artery (CCA) of rats using cine-gated PC-MRI and discuss relevant analysis methods. This procedure can be performed in a live, anesthetized animal and does not require euthanasia after the procedure. The proposed scanning parameters yield repeatable measurements for blood flow, indicating excellent reproducibility of the results. The PC-MRI procedure described in this article can be used for pharmacological testing, pathophysiological assessment, and cerebral hemodynamics evaluation.

The overall goal of this procedure is to measure the blood flow in the rat common carotid artery by using noninvasive phase contrast magnetic resonance imaging.

쥐 일반적인 경 동맥에 단계 대조 자기 공명 영상

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous ...

Quantification of Levator Ani Hiatus Enlargement by Magnetic Resonance Imaging in Males and Females with Pelvic Organ Prolapse

Here we present a protocol to examine the levator ani hiatus in males and females with pelvic organ prolapse, during the Valsalva maneuver and while evacuating acoustic gel, using a horizontally oriented 1.5 T magnetic resonance (MR) scanner. On midsagittal images, the vertical distance of pelvic organs is measured in millimeters relative to the hymen plane (female) and to the lower border of the symphysis pubis (male), preceded by - (above) or + ( below) signs. On axial images, the levator ani area is calculated in square centimeters with a free-hand tracing method from three key images, passing through the midsymphysis (level I), tangential to the lower border of the symphysis (level II), and at the maximal anterior rectal wall bulging (level III). Areas at rest and strained are compared to find evidence of a percentage of increase. The purpose is to provide objective evidence of the maximal extent of pelvic organs descent and hiatus enlargement without the interference of foreign objects or the examiner&#39;s proximity, so as to overcome the limitations of pelvic examination and transperineal sonography (i.e., subjectivity and sex-related limitations [female only]).

Here we present a protocol to standardize the measurement of the levator ani hiatus size&#160;by magnetic resonance imaging. The purpose is to extract biomechanical inferences from image analysis by comparing resting and straining values in patients of both sexes with pelvic prolapse, using consistent anatomical bony landmarks.

남성 및 여성 골반 기관 탈출으로에서 자기 공명 영상에 의해 Levator Ani 틈새 확대의 정량화

Here we present a protocol to examine the levator ani hiatus in males and females with pelvic organ prolapse, during the Valsalva maneuver and while ...

Quantitative Mapping of Specific Ventilation in the Human Lung using Proton Magnetic Resonance Imaging and Oxygen as a Contrast Agent

Specific ventilation imaging (SVI) is a functional magnetic resonance imaging technique capable of quantifying specific ventilation &#8213; the ratio of the fresh gas entering a lung region divided by the region&#8217;s end-expiratory volume &#8213; in the human lung, using only inhaled oxygen as a contrast agent. Regional quantification of specific ventilation has the potential to help identify areas of pathologic lung function. Oxygen in solution in tissue shortens the tissue&#8217;s longitudinal relaxation time (T1), and thus a change in tissue oxygenation can be detected as a change in T1-weighted signal with an inversion recovery acquired image. Following an abrupt change between two concentrations of inspired oxygen, the rate at which lung tissue within a voxel equilibrates to a new steady-state reflects the rate at which resident gas is being replaced by inhaled gas. This rate is determined by specific ventilation. To elicit this sudden change in oxygenation, subjects alternately breathe 20-breath blocks of air (21% oxygen) and 100% oxygen while in the MRI scanner. A stepwise change in inspired oxygen fraction is achieved through use of a custom three-dimensional (3D)-printed flow bypass system with a manual switch during a short end-expiratory breath hold. To detect the corresponding change in T1, a global inversion pulse followed by a single shot fast spin echo sequence was used to acquire two-dimensional T1-weighted images in a 1.5&#160;T MRI scanner, using an eight-element torso coil. Both single slice and multi-slice imaging are possible, with slightly different imaging parameters. Quantification of specific ventilation is achieved by correlating the time-course of signal intensity for each lung voxel with a library of simulated responses to the air/oxygen stimulus. SVI estimations of specific ventilation heterogeneity have been validated against multiple breath washout and proved to accurately determine the heterogeneity of the specific ventilation distribution.

Specific ventilation imaging is a functional magnetic resonance imaging technique that allows for quantification of regional specific ventilation in the human lung, using inhaled oxygen as a contrast agent. Here, we present a protocol to collect and analyze specific ventilation imaging data.

양성자 자기 공명 영상 및 조 영제로 산소를 사용 하 여 인간의 폐에 특정 통풍의 정량 매핑

Specific ventilation imaging (SVI) is a functional magnetic resonance imaging technique capable of quantifying specific ventilation &#8213; the ratio of ...

Human Fetal Blood Flow Quantification with Magnetic Resonance Imaging and Motion Compensation

Magnetic resonance imaging (MRI) is an important tool for the clinical assessment of cardiovascular morphology and heart function. It is also the recognized standard-of-care for blood flow quantification based on phase contrast MRI. While such measurement of blood flow has been possible in adults for decades, methods to extend this capability to fetal blood flow have only recently been developed.
Fetal blood flow quantification in major vessels is important for monitoring fetal pathologies such as congenital heart disease (CHD) and fetal growth restriction (FGR). CHD causes alterations in the cardiac structure and vasculature that change the course of blood in the fetus. In FGR, the path of blood flow is altered through the dilation of shunts such that the oxygenated blood supply to the brain is increased. Blood flow quantification enables assessment of the severity of the fetal pathology, which in turn allows for suitable&#160;in utero&#160;patient management and planning for postnatal care.
The primary challenges of applying phase contrast MRI to the human fetus include small blood vessel size, high fetal heart rate, potential MRI data corruption due to maternal respiration, unpredictable fetal movements, and lack of conventional cardiac gating methods to synchronize data acquisition. Here, we describe recent technical developments from our lab that have enabled the quantification of fetal blood flow using phase contrast MRI, including advances in accelerated imaging, motion compensation, and cardiac gating.

Here we present a protocol for measuring fetal blood flow rapidly with MRI and retrospectively performing motion correction and cardiac gating.

자기 공명 영상 및 모션 보상을 통한 인간 태아 혈류 정량화

Magnetic resonance imaging (MRI) is an important tool for the clinical assessment of cardiovascular morphology and heart function. It is also the ...

Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla

The overall goal of this article is to demonstrate a state-of-the-art ultrahigh field (UHF) magnetic resonance (MR) protocol of the brain at 7.0 Tesla in multiple sclerosis (MS) patients. MS is a chronic inflammatory, demyelinating, neurodegenerative disease that is characterized by white and gray matter lesions. Detection of spatially and temporally disseminated T2-hyperintense lesions by the use of MRI at 1.5 T and 3 T represents a crucial diagnostic tool in clinical practice to establish accurate diagnosis of MS based on the current version of the 2017 McDonald criteria. However, the differentiation of MS lesions from brain white matter lesions of other origins can sometimes be challenging due to their resembling morphology at lower magnetic field strengths (typically 3 T). Ultrahigh field MR (UHF-MR) benefits from increased signal-to-noise ratio and enhanced spatial resolution, both key to superior imaging for more accurate and definitive diagnoses of subtle lesions. Hence, MRI at 7.0 T has shown encouraging results to overcome the challenges of MS differential diagnosis by providing MS-specific neuroimaging markers (e.g., central vein sign, hypointense rim structures and differentiation of MS grey matter lesions). These markers and others can be identified by other MR contrasts other than T1 and T2 (T2*, phase, diffusion) and substantially improve the differentiation of MS lesions from those occurring in other neuroinflammatory conditions such as neuromyelitis optica and Susac syndrome. In this article, we describe our current technical approach to study cerebral white and grey matter lesions in MS patients at 7.0 T using different MR acquisition methods. The up-to-date protocol includes the preparation of the MR setup including the radio-frequency coils customized for UHF-MR, standardized screening, safety and interview procedures with MS patients, patient positioning in the MR scanner and acquisition of dedicated brain scans tailored for examining MS.

Here, we present a protocol to acquire magnetic resonance (MR) images of multiple sclerosis (MS) patient brains at 7.0 Tesla. The protocol includes preparation of the setup including the radio-frequency coils, standardized interview procedures with MS patients, subject positioning in the MR scanner and MR data acquisition.

7.0 테슬라에서 다발성 경화증의 자기 공명 화상 진찰

The overall goal of this article is to demonstrate a state-of-the-art ultrahigh field (UHF) magnetic resonance (MR) protocol of the brain at 7.0 Tesla in ...