Magnetic Resonance Imaging with Maximum Contrast between Two Selected Tissues Composed of Recordings with Three Repetition Times

1988 ◽  
Vol 29 (1) ◽  
pp. 140-142
Author(s):  
B. Jung ◽  
A. Ericsson ◽  
A. Hemmingsson ◽  
G. O. Sperber ◽  
K.-Å. Thuomas
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Liver Metastases ◽  
Normal Liver ◽  
Liver Parenchyma ◽  
Intensity Difference ◽  
Resonance Imaging ◽  
Mr Images ◽  
Imaging Parameters

A method is presented which in a composed image maximizes the image intensity difference between two selected tissues. The composition is made from several magnetic resonance (MR) images from the same slice but with different MR imaging parameters. The method is illustrated with a patient with liver metastases for whom the technique was used to emphasize metastases above normal liver parenchyma.

Magnetic resonance imaging: an accurate method to evaluate arteriovenous malformations after stereotactic radiosurgery

1996 ◽  
Vol 85 (6) ◽  
pp. 1044-1049 ◽  
Author(s):  
Bruce E. Pollock ◽  
Douglas Kondziolka ◽  
John C. Flickinger ◽  
Atul K. Patel ◽  
David J. Bissonette ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Cerebral Angiography ◽  
False Negative ◽  
Resonance Imaging ◽  
Mr Images ◽  
Content Type ◽  
Fine Print

✓ To determine the accuracy of magnetic resonance (MR) imaging in comparison to cerebral angiography after radiosurgery for an arteriovenous malformation (AVM), the authors reviewed the records of patients who underwent radiosurgery at the University of Pittsburgh Medical Center before 1992. All patients in the analysis had AVMs in which the flow-void signal was visible on preradiosurgical MR imaging. One hundred sixty-four postradiosurgical angiograms were obtained in 140 patients at a median of 2 months after postradiosurgical MR imaging (median 24 months after radiosurgery). Magnetic resonance imaging correctly predicted patency in 64 of 80 patients in whom patent AVMs were seen on follow-up angiography (sensitivity 80%) and angiographic obliteration in 84 of 84 patients (specificity 100%). Overall, 84 of 100 AVMs in which evidence of obliteration was seen on MR images displayed angiographic obliteration (negative predictive value, 84%). Ten of the 16 patients with false-negative MR images underwent follow-up angiography: in seven the lesions progressed to complete angiographic obliteration without further treatment. Exclusion of these seven patients from the false-negative MR imaging group increases the predictive value of a negative postradiosurgical MR image from 84% to 91%. No AVM hemorrhage was observed in clinical follow up of 135 patients after evidence of obliteration on MR imaging (median follow-up interval 35 months; range 2–96 months; total follow up 382 patient-years). Magnetic resonance imaging proved to be an accurate, noninvasive method for evaluating the patency of AVMs that were identifiable on MR imaging after stereotactic radiosurgery. This imaging modality is less expensive, more acceptable to patients, and does not have the potential for neurological complications that may be associated with cerebral angiography. The risk associated with follow-up cerebral angiography may no longer justify its role in the assessment of radiosurgical results in the treatment of AVMs.

Magnetic resonance imaging for detection of late meniscal tears in dogs following tibial tuberosity advancement for treatment of cranial cruciate ligament injury

2014 ◽  
Vol 27 (02) ◽  
pp. 141-146 ◽  
Author(s):  
C. R. Lamb ◽  
M. S. Tivers ◽  
A. Li ◽  
F. Taylor-Brown
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Cruciate Ligament ◽  
Meniscal Tear ◽  
Ligament Injury ◽  
Meniscal Tears ◽  
Resonance Imaging ◽  
Mr Images ◽  
Cranial Cruciate Ligament

SummaryTo document the use of and to estimate the accuracy of magnetic resonance (MR) imaging for detection of late meniscal tears in dogs with cranial cruciate ligament injury treated with tibial tuberosity advancement (TTA).Medical records of dogs that had TTA followed by stifle MR imaging for suspected meniscal tear and subsequent arthrotomy were reviewed retrospectively. Magnetic resonance images were reviewed independently by an observer blinded to clinical information who classified menisci as torn, abnormal but intact, or normal. Magnetic resonance and surgical findings were compared.Eight stifles from large breed dogs were included. Six stifles had a medial meniscal tear identified in MR images and later confirmed surgically. In the remaining two stifles, the menisci appeared intact in MR images and no tear was identified at subsequent arthrotomy. Lateral menisci in all stifles appeared intact in MR images and were considered normal at surgery. Susceptibility artefacts associated with TTA implants were present in all images but did not adversely affect interpretation of intra-articular structures.Magnetic resonance imaging appears to be accurate for diagnosis of late meniscal tears. Artefacts associated with TTA implants did not prevent evaluation of critical intra-articular structures. Further investigation with MR imaging should be considered when late meniscal tear is suspected following TTA.

Liver perfusion in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI): comparison of enhancement in Gd-BT-DO3A and Gd-EOB-DTPA in normal liver parenchyma

2014 ◽  
Vol 24 (9) ◽  
pp. 2146-2156 ◽  
Author(s):  
Hanke J. Schalkx ◽  
Marijn van Stralen ◽  
Kenneth Coenegrachts ◽  
Maurice A. A. J. van den Bosch ◽  
Charlotte S. van Kessel ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Liver Perfusion ◽  
Normal Liver ◽  
Liver Parenchyma ◽  
Resonance Imaging ◽  
Dce Mri ◽  
Dynamic Contrast Enhanced ◽  
Normal Liver Parenchyma ◽  
Contrast Enhanced

scholarly journals Gd3+-DTPA-Meglumine-Anionic Linear Globular Dendrimer G1: Novel Nanosized Low Toxic Tumor Molecular MR Imaging Agent

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Tahmineh Darvish Mohamadi ◽  
Massoud Amanlou ◽  
Negar Ghalandarlaki ◽  
Bita Mehravi ◽  
Mehdi Shafiee Ardestani ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Citric Acid ◽  
Magnetic Resonance ◽  
Early Diagnosis ◽  
Mr Imaging ◽  
Contrast Media ◽  
Cancer Treatment ◽  
Diagnostic Methods ◽  
Resonance Imaging ◽  
Mr Images

Despite the great efforts in the areas of early diagnosis and treatment of cancer, this disease continues to grow and is still a global killer. Cancer treatment efficiency is relatively high in the early stages of the disease. Therefore, early diagnosis is a key factor in cancer treatment. Among the various diagnostic methods, molecular imaging is one of the fastest and safest ones. Because of its unique characteristics, magnetic resonance imaging has a special position in most researches. To increase the contrast of MR images, many pharmaceuticals have been known and used so far. Gadopentetate (with commercial name Magnevist) is the first magnetic resonance imaging contrast media that has been approved by the US Food and Drug Administration. In this study, gadopentetate was first synthesized and then attached to a tree-like polymer called dendrimer which is formed by polyethylene glycol core and surrounding citric acid groups. Stability studies of the drug were carried out to ensure proper synthesis. Then, the uptake of the drug into liver hepatocellular cell line and the drug cytotoxicity were evaluated. Finally, in vitro and in vivo MR imaging were performed with the new synthetic drug. Based on the findings of this research, connecting gadopentetate to dendrimer surface produces a stronger, safer, and more efficient contrast media. Gd(III)-diethylenetriamine pentaacetate-meglumine-dendrimer drug has the ability to enter cells and does not produce significant cytotoxicity. It also increases the relaxivity of tissue and enhances the MR images contrast. The obtained results confirm the hypothesis that the binding of gadopentetate to citric acid dendrimer produces a new, biodegradable, stable, and strong version of the old contrast media.

Comparison of atlas- and magnetic resonance imaging—based stereotactic targeting of the globus pallidus internus in the performance of deep brain stimulation for the treatment of dystonia

2002 ◽  
Vol 96 (4) ◽  
pp. 673-679 ◽  
Author(s):  
Nathalie Vayssiere ◽  
Simone Hemm ◽  
Laura Cif ◽  
Marie Christine Picot ◽  
Nina Diakonova ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Deep Brain Stimulation ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Resonance Imaging ◽  
Mr Images ◽  
Content Type ◽  
Significant Difference ◽  
Fine Print ◽  
Deep Brain

Object. To assess the validity of relying on atlases during stereotactic neurosurgery, the authors compared target coordinates in the globus pallidus internus (GPi) obtained using magnetic resonance (MR) imaging with those determined using an atlas. The targets were used in deep brain stimulation (DBS) for the treatment of generalized dystonia. Methods. Thirty-five patients, who were treated using bilateral DBS of the GPi, were included in this study. The target was selected on three-dimensional MR images by direct visual recognition of the GPi. The coordinates were automatically recorded using dedicated software. They were translated into the anterior commissure—posterior commissure (AC—PC) coordinate system by using a matrix transformation process. The same GPi target was defined, based on the locations of brain structures shown in the atlases of Schaltenbrand and Talairach. Magnetic resonance imaging—based GPi target coordinates were statistically compared with the corresponding atlas-based coordinates by applying the Student t-test. A significant difference (p < 0.001) was demonstrated in x, y, and z directions between MR imaging—based and Schaltenbrand atlas—derived target coordinates. The comparison with normalized Talairach atlas coordinates demonstrated a significant difference (p < 0.01) in the y and z directions, although not in the x direction (p = 0.12). No significant correlation existed between MR imaging—based target coordinates and patient age (p > 0.1). No significant correlation was observed between MR imaging—based target coordinates and patient sex in the y and z directions (p > 0.9), although it was significant in the x direction (p < 0.05). A significant variation in coordinates and the length of the AC—PC line was revealed only in the y direction (p < 0.005). Conclusions. A significant difference was found between target coordinates obtained by direct visual targeting on MR images (validated by postoperative clinical results) and those obtained by indirect targeting based on atlases.

scholarly journals A Gadolinium(III) Complex Based on the Thymine Nucleobase with Properties Suitable for Magnetic Resonance Imaging

2021 ◽  
Vol 22 (9) ◽  
pp. 4586
Author(s):  
Marta Orts-Arroyo ◽  
Amadeo Ten-Esteve ◽  
Sonia Ginés-Cárdenas ◽  
Isabel Castro ◽  
Luis Martí-Bonmatí ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Lesion Detection ◽  
Resonance Imaging ◽  
X Ray Diffraction ◽  
Functional Images ◽  
High Relaxivity ◽  
Contrast Enhanced ◽  
Phantom Studies

The paramagnetic gadolinium(III) ion is used as contrast agent in magnetic resonance (MR) imaging to improve the lesion detection and characterization. It generates a signal by changing the relaxivity of protons from associated water molecules and creates a clearer physical distinction between the molecule and the surrounding tissues. New gadolinium-based contrast agents displaying larger relaxivity values and specifically targeted might provide higher resolution and better functional images. We have synthesized the gadolinium(III) complex of formula [Gd(thy)2(H2O)6](ClO4)3·2H2O (1) [thy = 5-methyl-1H-pyrimidine-2,4-dione or thymine], which is the first reported compound based on gadolinium and thymine nucleobase. 1 has been characterized through UV-vis, IR, SEM-EDAX, and single-crystal X-ray diffraction techniques, and its magnetic and relaxometric properties have been investigated by means of SQUID magnetometer and MR imaging phantom studies, respectively. On the basis of its high relaxivity values, this gadolinium(III) complex can be considered a suitable candidate for contrast-enhanced magnetic resonance imaging.

MRI Susceptibility Artefacts Related to Scaphoid Screws: the Effect of Screw Type, Screw Orientation and Imaging Parameters

2002 ◽  
Vol 27 (2) ◽  
pp. 165-170 ◽  
Author(s):  
M. GANAPATHI ◽  
G. JOSEPH ◽  
R. SAVAGE ◽  
A. R. JONES ◽  
B. TIMMS ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Titanium Alloy ◽  
Magnetic Resonance ◽  
Main Magnetic Field ◽  
Resonance Imaging ◽  
Metal Implants ◽  
Imaging Parameters ◽  
Susceptibility Artefact

Metal implants produce susceptibility artefacts in magnetic resonance imaging. We have explored the effects of scaphoid screw characteristics and orientation on MR susceptibility artefact. Titanium alloy, smallness and longitudinal alignment with the z-axis of the main magnetic field reduce the size of the susceptibility artefact.

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