scholarly journals Intact Plant Magnetic Resonance Imaging to Study Dynamics in Long-Distance Sap Flow and Flow-Conducting Surface Area

2007 ◽  
Vol 144 (2) ◽  
pp. 1157-1165 ◽  
Author(s):  
T.W.J. Scheenen ◽  
F.J. Vergeldt ◽  
A.M. Heemskerk ◽  
H. Van As
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Surface Area ◽  
Sap Flow ◽  
Intact Plant ◽  
Resonance Imaging ◽  
Conducting Surface ◽  
Long Distance

Regional measurements of pulmonary edema by using magnetic resonance imaging

1998 ◽  
Vol 84 (6) ◽  
pp. 2143-2153 ◽  
Author(s):  
S. D. Caruthers ◽  
C. B. Paschal ◽  
N. A. Pou ◽  
R. J. Roselli ◽  
T. R. Harris
Keyword(s):  
Magnetic Resonance Imaging ◽  
Oleic Acid ◽  
Magnetic Resonance ◽  
Pulmonary Edema ◽  
Surface Area ◽  
Extravascular Lung Water ◽  
Three Dimensional ◽  
Indicator Dilution ◽  
Resonance Imaging ◽  
Lung Water

A three-dimensional magnetic resonance imaging (MRI) method to measure pulmonary edema and lung microvascular barrier permeability was developed and compared with conventional methods in nine mongrel dogs. MRIs were obtained covering the entire lungs. Injury was induced by injection of oleic acid (0.021–0.048 ml/kg) into a jugular catheter. Imaging followed for 0.75–2 h. Extravascular lung water and permeability-related parameters were measured from multiple-indicator dilution curves. Edema was measured as magnetic resonance signal-to-noise ratio (SNR). Postinjury wet-to-dry lung weight ratio was 5.30 ± 0.38 ( n = 9). Extravascular lung water increased from 2.03 ± 1.11 to 3.00 ± 1.45 ml/g ( n = 9, P < 0.01). Indicator dilution studies yielded parameters characterizing capillary exchange of urea and butanediol: the product of the square root of equivalent diffusivity of escape from the capillary and capillary surface area ( D 1/2 S) and the capillary permeability-surface area product ( PS). The ratio of D 1/2 Sfor urea to D 1/2 Sfor butanediol increased from 0.583 ± 0.027 to 0.852 ± 0.154 ( n = 9, P < 0.05). Whole lung SNR at baseline, before injury, correlated with D 1/2 Sand PS ratios (both P < 0.02). By using rate of SNR change, the mismatch of transcapillary filtration flow and lymph clearance was estimated to be 0.2–1.8 ml/min. The filtration coefficient was estimated from these values. Results indicate that pulmonary edema formation during oleic acid injury can be imaged regionally and quantified globally, and the results suggest possible regional quantification by using three-dimensional MRI.

Dynamics of xylem and phloem sap flow in an outdoor zelkova tree visualized by magnetic resonance imaging

2019 ◽  
Vol 40 (3) ◽  
pp. 290-304
Author(s):  
Yasuhiko Terada ◽  
Yusuke Horikawa ◽  
Akiyoshi Nagata ◽  
Katsumi Kose ◽  
Kenji Fukuda
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Cross Section ◽  
Sap Flow ◽  
Diurnal Changes ◽  
Flow Volume ◽  
Resonance Imaging ◽  
Flow Measurements ◽  
Phloem Sap ◽  
Xylem Flow

Abstract Xylem and phloem sap flows in an intact, young Japanese zelkova tree (Zelkova serrata (Thunb.) Makino) growing outdoors were measured using magnetic resonance imaging (MRI). Two propagator-based sequences were developed for q-space imaging: pulse field gradient (PFG) with spin echo (PFG-SE) and stimulated echo (PFG-STE), which were used for xylem and phloem flow measurements, respectively. The data evaluation methods were improved to image fast xylem flow and slow phloem flow. Measurements were taken every 2–3 h for several consecutive days in August 2016, and diurnal changes in xylem and phloem sap flows in a cross-section of the trunk were quantified at a resolution of 1 mm2. During the day, apparent xylem flow volume exhibited a typical diurnal pattern following a vapor pressure deficit. The velocity mapping of xylem sap flow across the trunk cross section revealed that the greatest flow volume was found in current-year earlywood that had differentiated in April–May. The combined xylem flow in the 1- and 2-year-old annual rings also contributed to one-third of total sap flow. In the phloem, downward sap flow did not exhibit diurnal changes. This novel application of MRI in visualization of xylem and phloem sap flow by MRI is a promising tool for in vivo study of water transport in mature trees.

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