Search results for "MRI."
showing 10 items of 591 documents
Hyperpolarized 3helium gas as a novel contrast agent for functional MRI of ventilation.
2002
The use of inhaled hyperpolarized 3He gas in MRI is a recent approach for ventilation imaging. It has recently received enormous interest since it is capable of producing new and regional information on normal and abnormal lung ventilation. Promising preclinical and preliminary clinical results are the driving force to start phase II trials with patients suffering from obstructive and restrictive lung diseases.
Dynamic19F-MRI of pulmonary ventilation using sulfur hexafluoride (SF6) gas
2001
A new method for dynamic imaging of pulmonary wash-in and wash-out kinetics of inhaled sulfur hexafluoride (SF6) gas was developed. Measurements at the fluorine-19 Larmor frequency were performed in pigs using a gradient echo pulse sequence with 0.5 ms echo time and a measurement time of 9.1 s per image. Dynamic MRI was performed during wash-in and wash-out of SF6 gas in mechanically ventilated porcine lungs. A postprocessing strategy was developed for quantitative determination of wash-out time constants in the presence of noise. Mean wash-out constants were 4.78 ± 0.48 breaths vs. 4.33 ± 0.76 breaths for left and right lung when ventilation was performed with low tidal volume, and 1.73 ± …
Accomplishing the requirements within the new decree 159/2016: Comparative study of eddy currents induced in a human phantom moving near different MR…
2019
Purpose. In order to provide adequate risk-reducing procedures for MRI personnel (radiographers, anaesthetists, physicists, nurses, technicians, cleaners, etc.), different studies have been developed in the past years. Further to those, in the present work risk assessment concerned with currents induced by non-uniform static magnetic fields in MRI operators performing different tasks in prox imity of the scanner has been investigated across a set of different 1.5 T MRI scanners. Methods. The first step has been to empirically map the magnetic field around the different scanners and to select a proper adult human body as a heterogeneous volume conductor model. Then, upon observing the way ta…
Moving inside a MRI room: A risk assessment analysis
2018
Moving across the stray magnetic field generated by a medical magnetic resonance imaging system may induce electric stimulation near or even beyond the threshold of physiological significance and adequate risk-reducing procedures for the involved personnel may be re quired. With this in mind, a set of different scanners has been analysed. Results suggest that a 1.5 T magnet may be expected in general to comply with the requirements of the currently in force European Electromagnetic Fields Directive for ensuring the health and safety of workers.
Holmium(III) Single-Ion Magnet for Cryomagnetic Refrigeration Based on an MRI Contrast Agent Derivative
2021
The coexistence of field-induced blockage of the magnetization and significant magnetocaloric effects in the low-temperature region occurs in a mononuclear holmium(III) diethylenetriamine-N,N,N′,N″,N″-pentaacetate complex, whose gadolinium(III) analogue is a commercial MRI contrast agent. Both properties make it a suitable candidate for cryogenic magnetic refrigeration, thus enlarging the variety of applications of this simple class of multifunctional molecular nanomagnets.
MR enteroclysis versus conventional enteroclysis in Crohn’s disease patients
2009
Learning objectives: To provide a detailed step-by-step description of the technique of MR enteroclysis (MRE). To illustrate the spectrum of MRE findings in patients with Crohn’s disease (CD) and their correlation with findings at conventional enteroclysis (CE). To discuss the advantages and limitations of MRE in patients with CD. Background: CE is the gold standard for small bowel pathologies. However, submucosal and mesenteric involvements, which are common in CD, cannot be assessed by CE. Therefore, the evaluation of the mucosa alone by CE may under-represent the extent and activity of the disease. Also, CE is associated with the risk of several complications, mainly exacerbation in seve…
Role of MRI in the Assessment of Cervical Cancer
2023
: Cervical cancer is the fourth most common cancer in women, and it is divided into 2 main histological types: squamous cell carcinoma and adenocarcinoma. Extension of disease as well as the presence of metastases define the prognosis of patients. Accurate tumor staging at diagnosis is essential for adequate planning for treatment. There are several classifications of cervical cancer, and the most used are FIGO and TNM, which help classify the patient and guide the treatment. Imaging has a pivotal role in classifying patients, and MRI plays a decision-maker role both for diagnosis and for treatment planning. In this paper we highlight the role of MRI, alongside guidelines classification, in…
MRI in perianal Crohn’s disease: STIR versus T1w postcontrast fat-sat imaging
2009
Purpose: To evaluate the diagnostic accuracy of MRI, comparing STIR images versus T1w post-contrast fat-sat images in patients affected by perianal Crohn’s disease (CD). Material and methods: From January 2007 to July 2008, 73 patients with perianal CD underwent pelvic MRI using an external phased array coil. All studies were performed with a 1.5T MRI scanner. STIR and T1w post-contrast fat-sat images were independently analysed by two expert radiologists. Perianal fistulas were classified according to the Parks surgical classification. All patients underwent examination under anesthesia (EUA) that was considered gold standard. Results: By analysing STIR, images documented 31 simple fistula…