Magnetic resonance imaging of water movement through asparagus

2003 ◽  
Vol 30 (11) ◽  
pp. 1089 ◽  
Author(s):  
Julian A. Heyes ◽  
Christopher J. Clark
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Water Movement ◽  
Lateral Diffusion ◽  
Structural Features ◽  
Invasive Technique ◽  
Vascular Bundles ◽  
Lateral Movement ◽  
Resonance Imaging ◽  
Apoplastic Barrier

Asparagus spears are rapidly growing structures supplied with abundant vascular bundles. After extended periods of water loss, the stem surface becomes flaccid over a core of turgid tissue. We have used magnetic resonance imaging (MRI) coupled with a paramagnetic contrast reagent (Mn2+) to visualise water and ion movement within spear tissues. Using this technique we estimated the rate of water flow in the xylem and lateral movement out of the xylem into the surrounding tissues. Longitudinal flow rates of at least 3.7 mm min–1 and lateral diffusion rates of at least 17 μm min–1 were recorded. The outer parenchyma was difficult to label with vascular-supplied Mn2+, suggesting the presence of an apoplastic barrier. Stem shrinkage was greater in the outer parenchyma than in the inner cortex and pith parenchyma. Feeding the cut spear with 70 mM sucrose reduced the rate of lateral movement of Mn2+. The MRI technique highlighted differences in transport rates between adjacent vascular bundles and identified structural features with a resolution of 78 μm. This non-invasive technique is useful both for observing details of the transport paths in living tissue and for setting minimal estimates of transport rates.

scholarly journals Evaluation of Rectal and Skin Temperature Variations of Anesthetised Dogs Undergoing Magnetic Resonance Imaging Diagnosis

2019 ◽  
Vol 76 (2) ◽  
pp. 209
Author(s):  
Andra DEGAN ◽  
Ruxandra TUDOR ◽  
Ruxandra COSTEA ◽  
Dragoș BÎRȚOIU ◽  
Mihai SĂVESCU ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
General Anesthesia ◽  
Skin Temperature ◽  
Rectal Temperature ◽  
Thermal Imaging ◽  
Invasive Technique ◽  
Resonance Imaging ◽  
Temperature Variations ◽  
Before And After

General anesthesia produces different degrees of central nervous depression and changes in the peripheral circulation, therefore affecting the patient’s thermoregulatory mechanism. Moreover, the lack of proper, specially designed equipment for magnetic resonance imaging (MRI) environment monitoring can represent a challenge for the anesthetist. We examined the temperature variations correlated with different anesthetic protocols in dogs that underwent general anesthesia in order to evaluate changes in rectal and distal extremities temperature, before and after anesthesia. This study was conducted at the Faculty of Veterinary Medicine in Bucharest, on 21 dogs that were divided in 3 groups depending on the anesthetic protocol used. First group (B) received butorphanol (0.2 mg/kg, intravenously IV), second group (BK) had butorphanol (0.2 mg/kg) and a low dose of ketamine (2 mg/kg) IV, and group 3 (BM) was premedicated with butorphanol (0.2 mg/kg) and midazolam (0.2 mg/kg) IV. All patients were induced with propofol i.v. (3.24±0.68), intubated and maintained with isoflurane and oxygen. We determined rectal temperature before and right after the end of anesthesia with a digital thermometer and distal extremities temperature with the use of a thermal imaging camera attached to a smartphone. There was no significant difference between the rectal temperature before and after anesthesia within the 3 groups. Patients in group BK had a significant change in skin temperature at the end of anesthesia in all limbs (from 310C to 29.8 0C, p=0.008 and from 31 0C to 29.70C, p=0.009), respectively). Temperature variations were presented before and at the end of anesthesia, for all the groups especially at skin level. This study revealed that mobile thermal imaging represents a non-invasive technique that is helpful in assessing real time temperature changes in patients undergoing general anesthesia.

Noninvasive analysis of water movement in rat testis using deuterium magnetic resonance imaging

1996 ◽  
Vol 14 (1) ◽  
pp. 115-119
Author(s):  
Takayuki Obata ◽  
Hiroo Ikehira ◽  
Yasuhiro Ueshima ◽  
Hirotoshi Kato ◽  
Masahisa Koga ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Water Movement ◽  
Resonance Imaging ◽  
Rat Testis ◽  
Noninvasive Analysis

scholarly journals Characterizing water fingering phenomena in soils using magnetic resonance imaging and multifractal theory

2009 ◽  
Vol 16 (1) ◽  
pp. 159-168 ◽  
Author(s):  
A. Posadas ◽  
R. Quiroz ◽  
A. Tannús ◽  
S. Crestana ◽  
C. M. Vaz
Keyword(s):  
Magnetic Resonance Imaging ◽  
Steady State ◽  
Magnetic Resonance ◽  
Preferential Flow ◽  
Water Movement ◽  
Three Dimensions ◽  
Water Infiltration ◽  
Resonance Imaging ◽  
Flow Process ◽  
Multifractal Theory

Abstract. The study of water movement in soils is of fundamental importance in hydrologic science. It is generally accepted that in most soils, water and solutes flow through unsaturated zones via preferential paths or fingers. This paper combines magnetic resonance imaging (MRI) with both fractal and multifractal theory to characterize preferential flow in three dimensions. A cubic double-layer column filled with fine and coarse textured sand was placed into a 500 gauss MRI system. Water infiltration through the column (0.15×0.15×0.15 m3) was recorded in steady state conditions. Twelve sections with a voxel volume of 0.1×0.1×10 mm3 each were obtained and characterized using fractal and multifractal theory. The MRI system provided a detailed description of the preferential flow under steady state conditions and was also useful in understanding the dynamics of the formation of the fingers. The f(α) multifractal spectrum was very sensitive to the variation encountered at each horizontally-oriented slice of the column and provided a suitable characterization of the dynamics of the process identifying four spatial domains. In conclusion, MRI and fractal and multifractal analysis were able to characterize and describe the preferential flow process in soils. Used together, the two methods provide a good alternative to study flow transport phenomena in soils and in porous media.

scholarly journals Sensitivity of Magnetic Resonance Imaging in the Detection of Colorectal Liver Metastases

2008 ◽  
Vol 90 (1) ◽  
pp. 25-28 ◽  
Author(s):  
S Blyth ◽  
A Blakeborough ◽  
M Peterson ◽  
IC Cameron ◽  
AW Majeed
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Liver Metastases ◽  
Colorectal Liver Metastases ◽  
Imaging Modality ◽  
Invasive Technique ◽  
Resonance Imaging ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri ◽  
High Degree

INTRODUCTION The aim of this study was to evaluate the sensitivity of magnetic resonance imaging (MRI) in the detection of colorectal liver metastases. PATIENTS AND METHODS Pre-operative MRI scanning of the liver was performed by a single radiologist and the size and number of definite liver metastases were recorded. Patients then underwent hepatectomy with routine intra-operative ultrasonography (IOUS) and resected specimens were sent for histopathology. Pathology findings were compared with those of MRI scans to determine the sensitivity of this imaging modality. Exclusions were patients undergoing hepatic resection more than 4 weeks after the MRI scan, those undergoing chemotherapy at the time of the scan, and those with conglomerate unilobar metastases. RESULTS Complete data were available for 84 patients. There was total agreement between MRI, IOUS and histology in 79 patients (101 metastases). MRI missed 5 metastases in 5 patients that were found on IOUS (or palpation of superficial lesions) and subsequently confirmed by histological examination. These measured 5 mm or less (4 patients) and 7 mm (one patient). The sensitivity of MRI in the detection of colorectal liver metastases was thus 94% for all lesions and 100% for lesions 1 cm or larger in diameter. CONCLUSIONS MRI of the liver is a non-invasive technique with an extremely high degree of sensitivity in the detection of colorectal liver metastases and should be considered as the ‘gold standard’ in the pre-operative imaging of these patients.

Magnetic resonance imaging of wood

1986 ◽  
Vol 16 (2) ◽  
pp. 423-426 ◽  
Author(s):  
Laurance D. Hall ◽  
Vasanthan Rajanayagam ◽  
Wendy A. Stewart ◽  
Paul R. Steiner
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Structural Features ◽  
Annual Growth ◽  
Resonance Imaging ◽  
Growth Rings ◽  
Magnetic Resonance Scanner ◽  
Annual Growth Rings ◽  
Do So

A magnetic resonance scanner has been used to obtain images at 0.14 T, based on the water in aspen (Populustremuloides Michx.). In addition to visualization of the expected structural features such as annual growth-rings and knots, several additional features appear that require further study. Kiln-dried wood does not contain sufficient water to give an image, but can do so after impregnation with water.

scholarly journals Cardiac magnetic resonance imaging: the future is bright

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1636 ◽  
Author(s):  
Karthik Seetharam ◽  
Stamatios Lerakis
Keyword(s):  
Magnetic Resonance Imaging ◽  
Artificial Intelligence ◽  
Magnetic Resonance ◽  
Parallel Imaging ◽  
Imaging Techniques ◽  
T2 Mapping ◽  
Myocardial Strain ◽  
Invasive Technique ◽  
Resonance Imaging ◽  
Cmr Imaging

Over the last 15 years, cardiovascular magnetic resonance (CMR) imaging has progressively evolved to become an indispensable tool in cardiology. It is a non-invasive technique that enables objective and functional assessment of myocardial tissue. Recent innovations in magnetic resonance imaging scanner technology and parallel imaging techniques have facilitated the generation of T1 and T2 parametric mapping to explore tissue characteristics. The emergence of strain imaging has enabled cardiologists to evaluate cardiac function beyond conventional metrics. Significant progress in computer processing capabilities and cloud infrastructure has supported the growth of artificial intelligence in CMR imaging. In this review article, we describe recent advances in T1/T2 mapping, myocardial strain, and artificial intelligence in CMR imaging.

Endoscopic Fenestration of A Symptomatic Cavum Septum Pellucidum:Technical Case Report

2006 ◽  
Vol 59 (suppl_4) ◽  
pp. ONS-E491-ONS-E491 ◽  
Author(s):  
Astrid Weyerbrock ◽  
Todd Mainprize ◽  
James T. Rutka
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cerebrospinal Fluid ◽  
Magnetic Resonance ◽  
Clinical Symptoms ◽  
Pathological Condition ◽  
Obstructive Hydrocephalus ◽  
Invasive Technique ◽  
Resonance Imaging ◽  
Cerebrospinal Fluid Flow ◽  
Endoscopic Fenestration

Abstract OBJECTIVE: Cysts of the septum pellucidum (CSPs) may become symptomatic because of obstruction of cerebrospinal fluid flow, resulting in increased intracranial pressure and hydrocephalus requiring surgical intervention. Endoscopic fenestration may be the most effective and least invasive technique to treat this pathological condition. CLINICAL PRESENTATION: An 11-year-old boy sought treatment for frequent episodes of severe headache. On examination, he had papilledema. There was evidence on magnetic resonance imaging scans of a space-occupying CSP with obstructive hydrocephalus. INTERVENTION: The endoscopic technique of fenestration of both lateral walls of an enlarged CSP via a left frontal approach under ultrasound guidance using a rigid endoscope was successful. After surgery, the patient became asymptomatic, his papilledema resolved, and magnetic resonance imaging scans demonstrated collapse of the walls of the CSP toward the midline. CONCLUSION: Neuroendoscopic fenestration should be strongly considered as the treatment of choice for symptomatic CSPs. This procedure alone can lead to complete resolution of clinical symptoms and hydrocephalus, can reduce the size of the CSP, and can obviate the need for an implantable cerebrospinal fluid shunt.

scholarly journals Improving magnetic resonance imaging with smart and thin metasurfaces

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Endri Stoja ◽  
Simon Konstandin ◽  
Dennis Philipp ◽  
Robin N. Wilke ◽  
Diego Betancourt ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Patient Safety ◽  
Magnetic Resonance ◽  
Signal To Noise Ratio ◽  
Single Layer ◽  
Patient Specific ◽  
Invasive Technique ◽  
Resonance Imaging ◽  
Common Solution ◽  
Design Paradigm

AbstractOver almost five decades of development and improvement, Magnetic Resonance Imaging (MRI) has become a rich and powerful, non-invasive technique in medical imaging, yet not reaching its physical limits. Technical and physiological restrictions constrain physically feasible developments. A common solution to improve imaging speed and resolution is to use higher field strengths, which also has subtle and potentially harmful implications. However, patient safety is to be considered utterly important at all stages of research and clinical routine. Here we show that dynamic metamaterials are a promising solution to expand the potential of MRI and to overcome some limitations. A thin, smart, non-linear metamaterial is presented that enhances the imaging performance and increases the signal-to-noise ratio in 3T MRI significantly (up to eightfold), whilst the transmit field is not affected due to self-detuning and, thus, patient safety is also assured. This self-detuning works without introducing any additional overhead related to MRI-compatible electronic control components or active (de-)tuning mechanisms. The design paradigm, simulation results, on-bench characterization, and MRI experiments using homogeneous and structural phantoms are described. The suggested single-layer metasurface paves the way for conformal and patient-specific manufacturing, which was not possible before due to typically bulky and rigid metamaterial structures.

Magnetic resonance imaging in the diagnosis of brain arteriovenous malformations and in the evaluation of the results of stereotactic radiosurgery (review)

2021 ◽  
Vol 23 (1) ◽  
pp. 135-145
Author(s):  
A. S. Tokarev ◽  
S. A. Chuvilin ◽  
M. V. Neznanova
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Stereotactic Radiosurgery ◽  
Arteriovenous Malformations ◽  
Endovascular Embolization ◽  
Invasive Technique ◽  
Resonance Imaging ◽  
Factors Affecting ◽  
Risk Of Rupture ◽  
High Degree

Arteriovenous malformations (AVM) are quite rare, but they are dangerous pathology due to the risk of rupture and intracranial hemorrhage, which leads to disability. This review enlights the epidemiology of AVM and their symptoms, current methods of diagnostics and treatment as well as prognosis and treatment outcomes. Nowadays microsurgical removal, endovascular embolization, stereotactic radiosurgery and combination of these methods are used in clinical practice for AVMs treatment. Stereotactic radiosurgery is a highly effective non-invasive technique resulting in high degree of AVM obliteration with low risk of complications. The results of magnetic resonance imaging usage in assessing the degree of obliteration and the development of post-radiation complications are presented in this article. The optimization of magnetic resonance imaging algorithm is necessary for determination of statistically significant factors affecting the obliteration process.

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