Study of ice composites reinforced by nanosized alumina fibers using nuclear magnetic resonance methods

2021 ◽  
Vol 8 ◽  
pp. 9-18
Author(s):  
E.V. Morozov ◽  
◽  
A.S. Voronin ◽  
S.V. Kniga ◽  
V.M. Bouznik ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Front Propagation ◽  
Weak Effect ◽  
Resonance Imaging ◽  
Structural Effects ◽  
High Concentration ◽  
Melting Front ◽  
Transfer Processes ◽  
Alumina Fibers ◽  
High Degree

The aqueous suspensions of nanosized alumina fibers and ice composite materials based on them were studied using Pulsed-Field Gradient NMR and Magnetic Resonance Imaging methods. It is shown that the introduction of nanofibers does not lead to noticeable structural effects in suspensions in the concentration range of 1 - 10 wt. % Al2O3. It was found that a high concentration of filler significantly changes the morphology and texture of the ice matrix in composites: it becomes more homogeneous, with a high degree of continuity; when the melting front passes through, internal regions of thawing or failure of the integrity of the composite are not visualized. Yet the introduction of nanofibers into ice composites has a weak effect on the quantitative dynamics of heat transfer processes, making the rate of freezing/thawing front propagation to be similar in different samples at comparable temperatures of the process.

Hilar cholangiocarcinoma

2018 ◽  
Vol 1 (3) ◽  
pp. 28-30
Author(s):  
Tanita Suttichaimongkol
Keyword(s):  
Magnetic Resonance ◽  
Hilar Cholangiocarcinoma ◽  
Critical Role ◽  
Magnetic Resonance Cholangiopancreatography ◽  
Resonance Imaging ◽  
Extrahepatic Cholangiocarcinoma ◽  
Case Presentation ◽  
Duct Epithelium ◽  
Bile Duct Epithelium ◽  
High Degree

Cholangiocarcinoma is a primary biliary tract tumor arising from the bile duct epithelium. Classically, these tumors have been categorized according to their anatomic location as intrahepatic and extrahepatic. Hilar cholangiocarcinoma is the most common type of extrahepatic cholangiocarcinoma. It is the most difficult cancer to diagnose and therefore carries a poor prognosis with a 5-year survivalrate of less than 10%. Diagnostic imaging, coupled with a high degree of clinical suspicion, play a critical role in timely diagnosis, staging, and evaluation for surgical resectability. The most common imagingmodalities used for diagnosis and staging of hilar cholangiocarcinoma include ultrasound (US), computed tomography (CT), magnetic resonance imaging/magnetic resonance cholangiopancreatography(MRI/MRCP). This article showed a case presentation and reviewed the imaging appearance of hilar cholangiocarcinoma.   Figure 1  Greyscale sonography at the level of hepatic hilum revealed an ill-defined hilar mass (asterisk)resulting in upstream dilatation of right (arrow) and left (arrow head) main intrahepatic duct.  

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.

Are All Gadolinium-based Contrast Agents Similar? The Importance of High Stability, High Relaxivity and High Concentration

2009 ◽  
Vol 4 (2) ◽  
pp. 98 ◽  
Author(s):  
Nicoletta Anzalone ◽  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Contrast Agents ◽  
High Stability ◽  
Physicochemical Characteristics ◽  
Resonance Imaging ◽  
Contributing Factors ◽  
High Concentration ◽  
High Relaxivity ◽  
The Stability

Gadolinium-based contrast agents (GBCAs) are commonly used to enhance image acquisition via magnetic resonance imaging, but they differ in their physicochemical characteristics and therefore their function. The stability, concentration and relaxivity of a GBCA can have a major impact on clinical efficacy. Stability is related to safety. GBCAs can be categorised into three stability classes: non-ionic linear agents, ionic linear agents and macrocyclic agents, in order of increasing stability. Relaxivity and concentration are contributing factors to the level of enhancement that can be achieved with any given GBCA. Gadobutrol, gadobenate and gadoxetic acid have relatively high relaxivities. Among these compounds, only gadobutrol is commercially available at a higher concentration of 1.0M, whereas the others are used at a standard concentration of 0.5M. With high stability, relaxivity and concentration, gadobutrol has been shown in a number of clinical studies to be safe while improving image enhancement with increased conspicuity and sensitivity over other commonly used GBCAs.

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.

Intramuscular Hemangioma of the Posterior Belly of the Digastric Muscle Failing to Highlight on Magnetic Resonance Imaging

2002 ◽  
Vol 111 (11) ◽  
pp. 1050-1053 ◽  
Author(s):  
W. Andrew Clement ◽  
Iain Graham ◽  
David Rawlings ◽  
Mark Ablett ◽  
John H. Dempster
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Preoperative Diagnosis ◽  
Clinical Suspicion ◽  
Digastric Muscle ◽  
Resonance Imaging ◽  
Accurate Preoperative Diagnosis ◽  
Intramuscular Hemangioma ◽  
High Degree

Intramuscular hemangiomas of the digastric muscle are rare. We present the fifth case reported and the second to be imaged in vivo with magnetic resonance imaging. Accurate preoperative diagnosis of these lesions is difficult, but may be facilitated by a high degree of clinical suspicion and imaging. Magnetic resonance imaging using T2-weighted sequencing has been reported to effectively highlight these lesions. We present a case in which magnetic resonance imaging failed to highlight an intramuscular hemangioma of the posterior belly of the digastric muscle. Possible reasons for this failure are discussed.

scholarly journals Foetal magnetic resonance imaging: A necessity or adjunct? A modality comparison of in-utero ultrasound and ultrafast foetal magnetic resonance imaging

2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Sunaina Ramdass ◽  
Sumaiya Adam ◽  
Zarina Lockhat ◽  
Andries Masenge ◽  
Farhana E. Suleman
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Termination Of Pregnancy ◽  
Radiology Department ◽  
Resonance Imaging ◽  
Additional Information ◽  
Prognostic Accuracy ◽  
Magnetic Resonance Imaging Mri ◽  
High Degree ◽  
Foetal Mri

Background: Congenital anomalies occur in approximately 2% of newborns, resulting in severe medical, physical and social disabilities. Managing clinicians, therefore, require more confidence in their diagnosis and prognostic accuracy before appropriately counselling the parents regarding termination of pregnancy.Objective: The aim of this study was to investigate the role of magnetic resonance imaging (MRI) following the diagnosis of foetal anomalies at a foetomaternal unit of a tertiary South African institution.Methods: Eighty-eight pregnant women in their late second/third trimester who underwent both an ultrasound (US) at the foetomaternal unit and foetal MRI at the Radiology Department from 01 July 2013 to 30 September 2019 were included in this clinical study conducted at Steve Biko Academic Hospital.Results: Despite the high degree of concurrence (73.9%) between both modalities regarding the main diagnoses, MRI provided additional information in 45.5% of patients and changed the diagnosis in 25% of the patients. It further demonstrated superiority in providing diagnostic information in 97% of cases where the US alone was inadequate to counsel parents regarding the termination of pregnancy, and it completely changed the clinical management in 42% of cases.Conclusion: It is clearly evident from this study that foetal MRI is a necessity when termination of pregnancy is being considered following an US conducted by the foetomaternal unit. This allows for a complete foetal assessment and gives the managing clinician sufficient diagnostic confidence to prognosticate the future quality of life of the child.

scholarly journals Rathke's Cleft Cyst or Pituitary Apoplexy: A Case Report and Literature Review

2018 ◽  
Vol 6 (3) ◽  
pp. 544-547 ◽  
Author(s):  
Jeton Shatri ◽  
Ilir Ahmetgjekaj
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Signal Intensity ◽  
Pituitary Apoplexy ◽  
Rathke’S Cleft Cyst ◽  
Resonance Imaging ◽  
High Concentration ◽  
Rathke's Cleft Cyst ◽  
Rathke Cleft Cyst ◽  
Rathke's Cleft

BACKGROUND: During the examination of the sellar region by magnetic resonance imaging, hyperintensity in T1 weighted is a common finding. This signal intensity has different sources, and its significance depends on the clinical context. Pathologic variations in T1 signal hyperintensity may be related to clotting of blood (pituitary apoplexy) or the presence of a high concentration of protein (Rathke cleft cyst). The purpose of this study is to describe the significance of intracystic nodule, a diagnostic characteristic found in Rathke's cleft cyst, on MRI.CASE REPORT: We will present the case of a 20–year-old girl which referral to our hospital for head examination with magnetic resonance imaging because she has a post-traumatic headache. Pathological findings presented in T1-weighted hyperintensity intrasellar which persist even in T1 weighted-Fat suppression. These changes signal the presence of methemoglobin imposes. The patient is a referral to laboratory tests which result in rate except for slight value increase of prolactin. Recommended controller examination after a month but finding the same results which exclude the presence of methemoglobin.CONCLUSION: Morphological characteristics and signal intensity can impose the presence of high concentration of protein (Rathke cleft cyst).

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