Neural network diagnosis of avascular necrosis from magnetic resonance images

NASA Astrophysics Data System (ADS)

Manduca, Armando; Christy, Paul S.; Ehman, Richard L.

1993-09-01

We have explored the use of artificial neural networks to diagnose avascular necrosis (AVN) of the femoral head from magnetic resonance images. We have developed multi-layer perceptron networks, trained with conjugate gradient optimization, which diagnose AVN from single sagittal images of the femoral head with 100% accuracy on the training data and 97% accuracy on test data. These networks use only the raw image as input (with minimal preprocessing to average the images down to 32 X 32 size and to scale the input data values) and learn to extract their own features for the diagnosis decision. Various experiments with these networks are described.

Magnetic resonance imaging of appendicular musculoskeletal infection.

PubMed

Lalam, Radhesh K; Cassar-Pullicino, Victor N; Tins, Bernhard J

2007-06-01

Appendicular skeletal infection includes osseous and extraosseous infections. Skeletal infection needs early diagnosis and appropriate management to prevent long-term morbidity. Magnetic resonance imaging is the best imaging modality to diagnose skeletal infection early in most circumstances. This article describes the role of magnetic resonance imaging in relation to the other available imaging modalities in the diagnosis of skeletal infection. Special circumstances such as diabetic foot, postoperative infection, and chronic recurrent multifocal osteomyelitis are discussed separately.

Reliability of clinical findings and magnetic resonance imaging for the diagnosis of chondromalacia patellae.

PubMed

Pihlajamäki, Harri K; Kuikka, Paavo-Ilari; Leppänen, Vesa-Veikko; Kiuru, Martti J; Mattila, Ville M

2010-04-01

This diagnostic study was performed to determine the correlation between anterior knee pain and chondromalacia patellae and to define the reliability of magnetic resonance imaging for the diagnosis of chondromalacia patellae. Fifty-six young adults (median age, 19.5 years) with anterior knee pain had magnetic resonance imaging of the knee followed by arthroscopy. The patellar chondral lesions identified by magnetic resonance imaging were compared with the arthroscopic findings. Arthroscopy confirmed the presence of chondromalacia patellae in twenty-five (45%) of the fifty-six knees, a synovial plica in twenty-five knees, a meniscal tear in four knees, and a femorotibial chondral lesion in four knees; normal anatomy was seen in six knees. No association was found between the severity of the chondromalacia patellae seen at arthroscopy and the clinical symptoms of anterior knee pain syndrome (p = 0.83). The positive predictive value for the ability of 1.0-T magnetic resonance imaging to detect chondromalacia patellae was 75% (95% confidence interval, 53% to 89%), the negative predictive value was 72% (95% confidence interval, 56% to 84%), the sensitivity was 60% (95% confidence interval, 41% to 77%), the specificity was 84% (95% confidence interval, 67% to 93%), and the diagnostic accuracy was 73% (95% confidence interval, 60% to 83%). The sensitivity was 13% (95% confidence interval, 2% to 49%) for grade-I lesions and 83% (95% confidence interval, 59% to 94%) for grade-II, III, or IV lesions. Chondromalacia patellae cannot be diagnosed on the basis of symptoms or with current physical examination methods. The present study demonstrated no correlation between the severity of chondromalacia patellae and the clinical symptoms of anterior knee pain syndrome. Thus, symptoms of anterior knee pain syndrome should not be used as an indication for knee arthroscopy. The sensitivity of 1.0-T magnetic resonance imaging was low for grade-I lesions but considerably higher for more

Physics of a novel magnetic resonance and electrical impedance combination for breast cancer diagnosis

NASA Astrophysics Data System (ADS)

Kallergi, Maria; Heine, John J.; Wollin, Ernest

2015-03-01

A new technique is proposed and experimentally validated for breast cancer detection and diagnosis. The technique combines magnetic resonance with electrical impedance measurements and has the potential to increase the specificity of magnetic resonance mammography (MRM) thereby reducing false positive biopsy rates. The new magnetic resonance electrical impedance mammography (MREIM) adds a time varying electric field during a supplementary sequence to a standard MRM examination with an apparatus that is "invisible" to the patient. The applied electric field produces a current that creates an additional magnetic field with a component aligned with the bore magnetic field that can alter the native signal in areas of higher electrical conductivity. The justification for adding the electric field is that the electrical conductivity of cancerous breast tissue is approximately 3-40 times higher than normal breast tissue and, hence, conductivity of malignant tissue represents a known clinical disease biomarker. In a pilot study with custom-made phantoms and experimental protocols, it was demonstrated that MREIM can produce, as theoretically predicted, a detectable differential signal in areas of higher electrical conductivity (tumor surrogate regions); the evidence indicates that the differential signal is produced by the confluence of two different effects at full image resolution without gadolinium chelate contrast agent injection, without extraneous reconstruction techniques, and without cumbersome multi-positioned patient electrode configurations. This paper describes the theoretical model that predicts and explains the observed experimental results that were also confirmed by simulation studies.

Diagnosis of Bell palsy with gadolinium magnetic resonance imaging.

PubMed

Becelli, R; Perugini, M; Carboni, A; Renzi, G

2003-01-01

Bell palsy is a condition resulting from a peripheral edematous compression on the nervous fibers of the facial nerve. This pathological condition often has clinical characteristics of no importance and spontaneously disappears in a short time in a high percentage of cases. Facial palsy concerning cranial nerve VII can also be caused by other conditions such as mastoid fracture, acoustic neurinoma, tumor spread to the temporal lobe (e.g., cholesteatoma), neoformation of the parotid gland, Melkersson-Rosenthal syndrome, and Ramsay-Hunt syndrome. Therefore, it is important to adopt an accurate diagnostic technique allowing the rapid detection of Bell palsy and the exclusion of causes of facial paralysis requiring surgical treatment. Magnetic resonance imaging (MRI) with medium contrast of the skull shows a marked increase in revealing lesions, even of small dimensions, inside the temporal bone and at the cerebellopontine angle. The authors present a clinical case to show the important role played by gadolinium MRI in reaching a diagnosis of Bell palsy in the differential diagnosis of the various conditions that determine paralysis of the facial nerve and in selecting the most suitable treatment or surgery to be adopted.

Ultrasonography and magnetic resonance imaging in the diagnosis of Morton's neuroma.

PubMed

Fazal, Muhammad Ali; Khan, Ishrat; Thomas, Cherian

2012-01-01

Magnetic resonance imaging (MRI) and ultrasonography are used widely for the diagnosis of Morton's neuroma. The aim of this study was to assess the accuracy of these two modalities as diagnostic tools in Morton's neuroma. Fifty feet of 47 consecutive patients (39 women and 8 men; mean age, 46 years; age range, 36-64 years) who presented between January 1, 2005, and June 30, 2008, were included in the study. Twenty-five feet were investigated with ultrasonography and 25 with MRI. Morton's neuroma was confirmed surgically and histologically in all of the patients. A Student unpaired t test was applied. Twenty-two MRIs were diagnostic (sensitivity, 88%). Three patients with negative MRI findings underwent ultrasonography and were found to have a neuroma smaller than 5 mm. Twenty-four ultrasound scans demonstrated the neuroma (sensitivity, 96%), with five neuromas being smaller than 5 mm. Ultrasonography has a slightly higher sensitivity in the diagnosis of Morton's neuroma, particularly of neuromas smaller than 5 mm, and should be the preferred imaging modality in suspected cases, and MRI should be reserved for cases with equivocal diagnosis.

Liver Function Assessment by Magnetic Resonance Imaging.

PubMed

Ünal, Emre; Akata, Deniz; Karcaaltincaba, Musturay

2016-12-01

Liver function assessment by hepatocyte-specific contrast-enhanced magnetic resonance imaging is becoming a new biomarker. Liver function can be assessed by T1 mapping (reduction rate) and signal intensity measurement (relative enhancement ratio) before and after GD-EOB-DTPA (gadoxetic acid) administration, as alternative to Tc-99m galactosyl serum albumin scintigraphy, 99m Tc-labeled mebrofenin scintigraphy, and indocyanine green clearance test. Magnetic resonance imaging assessment of liver function can enable diagnosis of cirrhosis, nonalcoholic fatty liver disease associated fibrosis and steatohepatitis, primary sclerosing cholangitis, toxic hepatitis, and chemotherapy and radiotherapy-related changes, which may be only visible on hepatobiliary phase images. Simple visual assessment of signal intensity at hepatobiliary phase images is important for the diagnosis of different patterns of liver dysfunction including diffuse, lobar, segmental, and subsegmental forms. Furthermore, preoperative assessment of liver function is feasible before oncologic hepatic surgery, which may be important to prevent posthepatectomy liver failure and to estimate future remnant volume. Functional magnetic resonance cholangiography obtained by T1-weighted images at hepatobiliary phase can allow diagnosis of acalculous cholecystitis, biliary leakage, bile reflux to the stomach, sphincter of oddi dysfunction, and lesions with communication to biliary tree. Functional information can be easily obtained when Gd-EOB-DTPA is used for liver magnetic resonance imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparing Magnetic Resonance Imaging and High-Resolution Dynamic Ultrasonography for Diagnosis of Plantar Plate Pathology: A Case Series.

PubMed

Donegan, Ryan J; Stauffer, Anthony; Heaslet, Michael; Poliskie, Michael

Plantar plate pathology has gained noticeable attention in recent years as an etiology of lesser metatarsophalangeal joint pain. The heightened clinical awareness has led to the need for more effective diagnostic imaging accuracy. Numerous reports have established the accuracy of both magnetic resonance imaging and ultrasonography for the diagnosis of plantar plate pathology. However, no conclusions have been made regarding which is the superior imaging modality. The present study reports a case series directly comparing high-resolution dynamic ultrasonography and magnetic resonance imaging. A multicenter retrospective comparison of magnetic resonance imaging versus high-resolution dynamic ultrasonography to evaluate plantar plate pathology with surgical confirmation was conducted. The sensitivity, specificity, and positive and negative predictive values for magnetic resonance imaging were 60%, 100%, 100%, and 33%, respectively. The overall diagnostic accuracy compared with the intraoperative findings was 66%. The sensitivity, specificity, and positive and negative predictive values for high-resolution dynamic ultrasound imaging were 100%, 100%, 100%, and 100%, respectively. The overall diagnostic accuracy compared with the intraoperative findings was 100%. The p value using Fisher's exact test for magnetic resonance imaging and high-resolution dynamic ultrasonography was p = .45, a difference that was not statistically significant. High-resolution dynamic ultrasonography had greater accuracy than magnetic resonance imaging in diagnosing lesser metatarsophalangeal joint plantar plate pathology, although the difference was not statistically significant. The present case series suggests that high-resolution dynamic ultrasonography can be considered an equally accurate imaging modality for plantar plate pathology at a potential cost savings compared with magnetic resonance imaging. Therefore, high-resolution dynamic ultrasonography warrants further investigation in

The value of magnetic resonance imaging in the diagnosis of penile fracture

PubMed Central

Guler, Ibrahim; Ödev, Kemal; Kalkan, Havva; Simsek, Cihan; Keskin, Suat; Kilinç, Mehmet

2015-01-01

Purpose We studied the use of magnetic resonance imaging in the diagnosis of penile fracture. Materials and Methods Between 1997 and 2012, fifteen patients (age range 17-48 years, mean age 37 years) with suspected penile fracture underwent MRI examinations. Ten patients were injured during sexual intercourse, whereas four patients were traumatized by non-physiological bending of the penis during self manupilation, one patient was traumatized falling from the bed. Investigations were performed with 1.5T MR unit. With the patient in the supine position, the penis was taped against the abdominal wall and surface coil was placed on the penis. All patients were studied with axial, coronal, sagittal precontrast and postcontrast T1-weighted TSE(TR/TE:538/13 msn) and T2-weighted TSE(5290/110 msn) sequences. All patient underwent surgical exploration. The follow-up ranged from 3 months to 72 months. Clinically all patients showed normal healing process without complications. In 11 patients a shortening and thickening of tunica albuginea was observed. Three patients have post traumatic erectil disfunction. Results In all patient corpus cavernosum fractures were clearly depicted on a discontinuity of the low signal intensity of tunica albuginea. These findings were most evident on T1WI and also depicted on T2W sequences. Images obtained shortly after contrast medium administration showed considerable enhancement only in rupture site. Subcutaneous extratunical haematoma in all patients were also recognizable on T2 WI. MRI findings were confirmed at surgery. Conclusions Magnetic resonance imaging is of great value for the diagnosis of penile fracture. Furthermore this method is well suited for visualising the post-operative healing process PMID:26005975

The value of magnetic resonance imaging in the diagnosis of penile fracture.

PubMed

Guler, Ibrahim; Ödev, Kemal; Kalkan, Havva; Simsek, Cihan; Keskin, Suat; Kilinç, Mehmet

2015-01-01

We studied the use of magnetic resonance imaging in the diagnosis of penile fracture. Between 1997 and 2012, fifteen patients (age range 17-48 years, mean age 37 years) with suspected penile fracture underwent MRI examinations. Ten patients were injured during sexual intercourse, whereas four patients were traumatized by non-physiological bending of the penis during self manupilation, one patient was traumatized falling from the bed. Investigations were performed with 1.5 T MR unit. With the patient in the supine position, the penis was taped against the abdominal wall and surface coil was placed on the penis. All patients were studied with axial, coronal, sagittal precontrast and postcontrast T1-weighted TSE(TR/TE:538/13 msn) and T2-weighted TSE(5290/110 msn) sequences. All patient underwent surgical exploration. The follow-up ranged from 3 months to 72 months. Clinically all patients showed normal healing process without complications. In 11 patients a shortening and thickening of tunica albuginea was observed. Three patients have post traumatic erectile disfunction. In all patient corpus cavernosum fractures were clearly depicted on a discontinuity of the low signal intensity of tunica albuginea. These findings were most evident on T1WI and also depicted on T2W sequences. Images obtained shortly after contrast medium administration showed considerable enhancement only in rupture site. Subcutaneous extratunical haematoma in all patients were also recognizable on T2 WI. MRI findings were confirmed at surgery. Magnetic resonance imaging is of great value for the diagnosis of penile fracture. Furthermore this method is well suited for visualising the post-operative healing process.

Imaging of juvenile spondyloarthritis. Part II: Ultrasonography and magnetic resonance imaging

PubMed Central

Znajdek, Michał; Gietka, Piotr; Vasilevska-Nikodinovska, Violeta; Patrovic, Lukas; Salapura, Vladka

2017-01-01

Juvenile spondyloarthropathies are mainly manifested by symptoms of peripheral arthritis and enthesitis. Early involvement of sacroiliac joints and spine is exceptionally rare in children; this usually happens in adulthood. Conventional radiographs visualize late inflammatory lesions. Early diagnosis is possible with the use of ultrasonography and magnetic resonance imaging. The first part of the article presented classifications and radiographic presentation of juvenile spondyloarthropathies. This part discusses changes seen on ultrasonography and magnetic resonance imaging. In patients with juvenile spondyloarthropathies, these examinations are conducted to diagnose inflammatory lesions in peripheral joints, tendon sheaths, tendons and bursae. Moreover, magnetic resonance also shows subchondral bone marrow edema, which is considered an early sign of inflammation. Ultrasonography and magnetic resonance imaging do not show specific lesions for any rheumatic disease. Nevertheless, they are conducted for early diagnosis, treatment monitoring and identifying complications. This article presents a spectrum of inflammatory changes and discusses the diagnostic value of ultrasonography and magnetic resonance imaging. PMID:29075522

Novel detection schemes of nuclear magnetic resonance and magnetic resonance imaging: applications from analytical chemistry to molecular sensors.

PubMed

Harel, Elad; Schröder, Leif; Xu, Shoujun

2008-01-01

Nuclear magnetic resonance (NMR) is a well-established analytical technique in chemistry. The ability to precisely control the nuclear spin interactions that give rise to the NMR phenomenon has led to revolutionary advances in fields as diverse as protein structure determination and medical diagnosis. Here, we discuss methods for increasing the sensitivity of magnetic resonance experiments, moving away from the paradigm of traditional NMR by separating the encoding and detection steps of the experiment. This added flexibility allows for diverse applications ranging from lab-on-a-chip flow imaging and biological sensors to optical detection of magnetic resonance imaging at low magnetic fields. We aim to compare and discuss various approaches for a host of problems in material science, biology, and physics that differ from the high-field methods routinely used in analytical chemistry and medical imaging.

Magnetic resonance imaging based clinical research in Alzheimer's disease.

PubMed

Fayed, Nicolás; Modrego, Pedro J; Salinas, Gulillermo Rojas; Gazulla, José

2012-01-01

Alzheimer's disease (AD) is the most common cause of dementia in elderly people in western countries. However important goals are unmet in the issue of early diagnosis and the development of new drugs for treatment. Magnetic resonance imaging (MRI) and volumetry of the medial temporal lobe structures are useful tools for diagnosis. Positron emission tomography is one of the most sensitive tests for making an early diagnosis of AD but the cost and limited availability are important caveats for its utilization. The importance of magnetic resonance techniques has increased gradually to the extent that most clinical works based on AD use these techniques as the main aid to diagnosis. However, the accuracy of structural MRI as biomarker of early AD generally reaches an accuracy of 80%, so additional biomarkers should be used to improve predictions. Other structural MRI (diffusion weighted, diffusion-tensor MRI) and functional MRI have also added interesting contribution to the understanding of the pathophysiology of AD. Magnetic resonance spectroscopy has proven useful to monitor progression and response to treatment in AD, as well as a biomarker of early AD in mild cognitive impairment.

Magnetic Resonance Imaging of Tumors with the Use of Iron Oxide Magnetic Nanoparticles as a Contrast Agent.

PubMed

Semkina, A S; Abakumov, M A; Grinenko, N F; Lipengolts, A A; Nukolova, N V; Chekhonin, V P

2017-04-01

We studied the possibility of using BSA-coated magnetic iron oxide nanoparticles for magnetic resonance imaging diagnosis of C6 glioblastoma, 4T1 mammary adenocarcinoma, and RS-1 hepatic mucous carcinoma. In all three cases, magnetic nanoparticles accumulated in the tumor and its large vessels. Magnetic resonance imaging with contrast agent allows visualization of the tumor tissue and its vascularization.

Intensity-Curvature Measurement Approaches for the Diagnosis of Magnetic Resonance Imaging Brain Tumors.

PubMed

Ciulla, Carlo; Veljanovski, Dimitar; Rechkoska Shikoska, Ustijana; Risteski, Filip A

2015-11-01

This research presents signal-image post-processing techniques called Intensity-Curvature Measurement Approaches with application to the diagnosis of human brain tumors detected through Magnetic Resonance Imaging (MRI). Post-processing of the MRI of the human brain encompasses the following model functions: (i) bivariate cubic polynomial, (ii) bivariate cubic Lagrange polynomial, (iii) monovariate sinc, and (iv) bivariate linear. The following Intensity-Curvature Measurement Approaches were used: (i) classic-curvature, (ii) signal resilient to interpolation, (iii) intensity-curvature measure and (iv) intensity-curvature functional. The results revealed that the classic-curvature, the signal resilient to interpolation and the intensity-curvature functional are able to add additional information useful to the diagnosis carried out with MRI. The contribution to the MRI diagnosis of our study are: (i) the enhanced gray level scale of the tumor mass and the well-behaved representation of the tumor provided through the signal resilient to interpolation, and (ii) the visually perceptible third dimension perpendicular to the image plane provided through the classic-curvature and the intensity-curvature functional.

Intensity-Curvature Measurement Approaches for the Diagnosis of Magnetic Resonance Imaging Brain Tumors

PubMed Central

Ciulla, Carlo; Veljanovski, Dimitar; Rechkoska Shikoska, Ustijana; Risteski, Filip A.

2015-01-01

This research presents signal-image post-processing techniques called Intensity-Curvature Measurement Approaches with application to the diagnosis of human brain tumors detected through Magnetic Resonance Imaging (MRI). Post-processing of the MRI of the human brain encompasses the following model functions: (i) bivariate cubic polynomial, (ii) bivariate cubic Lagrange polynomial, (iii) monovariate sinc, and (iv) bivariate linear. The following Intensity-Curvature Measurement Approaches were used: (i) classic-curvature, (ii) signal resilient to interpolation, (iii) intensity-curvature measure and (iv) intensity-curvature functional. The results revealed that the classic-curvature, the signal resilient to interpolation and the intensity-curvature functional are able to add additional information useful to the diagnosis carried out with MRI. The contribution to the MRI diagnosis of our study are: (i) the enhanced gray level scale of the tumor mass and the well-behaved representation of the tumor provided through the signal resilient to interpolation, and (ii) the visually perceptible third dimension perpendicular to the image plane provided through the classic-curvature and the intensity-curvature functional. PMID:26644943

Liver biopsy for diagnosis of presumed benign hepatocellular lesions lacking magnetic resonance imaging diagnostic features of focal nodular hyperplasia.

PubMed

Sannier, Aurélie; Cazejust, Julien; Lequoy, Marie; Cervera, Pascale; Scatton, Olivier; Rosmorduc, Olivier; Wendum, Dominique

2016-11-01

The contribution of liver biopsy for the diagnosis of presumed benign hepatocellular lesions lacking the diagnostic features of focal nodular hyperplasia (FNH) on magnetic resonance imaging (MRI) is unknown. We evaluated liver biopsy and MRI performances in this setting. Magnetic resonance imaging and slides of liver biopsies performed for a presumed benign hepatocellular lesion (2006-2013) without the typical features of FNH on MRI were blindly reviewed (n = 45). Eighteen lesions were surgically removed and also analyzed. The final diagnosis was the diagnosis established after surgery or on the biopsy in the absence of surgery. The final diagnosis was FNH (n = 19), hepatocellular adenoma (HCA, n = 15), hepatocellular carcinoma (n = 3) and indefinite (n = 4). Four lesions corresponded to non hepatocellular lesions. FNH, HNF1A mutated and inflammatory HCA were diagnosed accurately on the biopsy in 95%, 67% and 100% of the cases respectively. Diagnostic performance of liver biopsy for HNF1A mutated HCA was lower because of the lack of non-tumoral tissue. Diagnosis based on morphological analysis was certain and correct in 27 cases. Immunostaining allowed a definite diagnosis in 12 additionnal cases. Radiological diagnosis was in agreement with the histological diagnosis in 75.6% of the cases, with a very high sensitivity (97%) and specificity (100%) for the diagnosis of HNF1A mutated HCA. Liver biopsy has a good diagnostic performance particularly for FNH and inflammatory HCA, and sampling of non-lesional tissue is highly recommended. A biopsy does not seem necessary if H-HCA is diagnosed on MRI. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Definitive diagnosis of breast implant rupture using magnetic resonance imaging.

PubMed

Ahn, C Y; Shaw, W W; Narayanan, K; Gorczyca, D P; Sinha, S; Debruhl, N D; Bassett, L W

1993-09-01

Breast implant rupture is an important complication of augmented and reconstructed breasts. Although several techniques such as mammography, xeromammography, ultrasound, thermography, and computed tomographic (CT) scanning have been proven to be useful to detect implant rupture, they have several disadvantages and lack specificity. In the current study, we have established magnetic resonance imaging (MRI) as a definitive, reliable, and reproducible technique to diagnose both intracapsular and extracapsular ruptures. The study was conducted in 100 symptomatic patients. Our imaging parameters were able to identify ruptures in implants with silicone shells. All the ruptures showed the presence of wavy lines, free-floating silicone shell within the gel ("free-floating loose-thread sign" or "linguine sign"). We had a 3.75 percent incidence of false-positive and false-negative results. The sensitivity for detection of silicone implant rupture was 76 percent, with a specificity of 97 percent. In addition, we also were able to identify the artifacts that may interfere with the definitive diagnosis of implant rupture.

Magnetic resonance imaging findings in Ménière's disease.

PubMed

Patel, V A; Oberman, B S; Zacharia, T T; Isildak, H

2017-07-01

To identify and evaluate cranial magnetic resonance imaging findings associated with Ménière's disease. Seventy-eight patients with a documented diagnosis of Ménière's disease and 35 controls underwent 1.5 T or 3 T magnetic resonance imaging of the brain. Patients also underwent otological, vestibular and audiometric examinations. Lack of visualisation of the left and right vestibular aqueducts was identified as statistically significant amongst Ménière's disease patients (left, p = 0.0001, odds ratio = 0.02; right, p = 0.0004, odds ratio = 0.03). Both vestibular aqueducts were of abnormal size in the Ménière's disease group, albeit with left-sided significance (left, p = 0.008, odds ratio = 10.91; right, p = 0.49, odds ratio = 2.47). Lack of vestibular aqueduct visualisation on magnetic resonance imaging was statistically significant in Ménière's disease patients compared to the general population. The study findings suggest that magnetic resonance imaging can be useful to rule out retrocochlear pathology and provide radiological data to support the clinical diagnosis of Ménière's disease.

Contrast enhanced ultrasound and magnetic resonance imaging in hepatocellular carcinoma diagnosis.

PubMed

Dumitrescu, Cristiana I; Gheonea, Ioana A; Săndulescu, Larisa; Surlin, Valeriu; Săftoiu, Adrian; Dumitrescu, Daniela

2013-12-01

The new developments in imaging technology, including contrast enhanced ultrasound (CEUS), computed tomography (CT), and magnetic resonance imaging (MRI), allow a better diagnosis of both malignant and benign liver lesions. A retrospective trial of 126 patients was conducted in the Gastroenterology and Imaging Departments of the University of Medicine and Pharmacy Craiova, Romania. CEUS and MRI were the imaging techniques used for diagnosis of focal liver lesions (FLL), especially for hepatocellular carcinoma (HCC). Histopathology was used only in 15 cases. For each method of investigation we calculated the sensitivity, specificity, positive and negative predictive values (PPV and NPV), positive and negative likelihood ratio (+LR, -LR), accuracy and we compared the ROC curves. Statistical analysis also included the Chi-square and Kappa tests. Seventy six cases were diagnosed as HCC, with average size of 5.2±3.3 cm in diameter. The sensitivity and specificity were 71.4% and 95.6% for CEUS and 91.4%, 98.9% respectively, for MRI. When comparing the ROC curves, we found a higher area under curve for MRI (0.952) then for CEUS (0.835) (p=0.005), and 95% confidence interval of 0.0343 to 0.199. No statistically significant difference in diagnosis of FLL was found between CEUS and MRI (p > 0.05) and the agreement between the two imaging techniques was good (k = 0.78). CEUS can be used as the first step in the diagnosis of liver lesions, but MRI remains the gold standard diagnostic method for liver tumors.

Magnetic resonance imaging is often misleading when used as an adjunct to ultrasound in the management of placenta accreta spectrum disorders.

PubMed

Einerson, Brett D; Rodriguez, Christina E; Kennedy, Anne M; Woodward, Paula J; Donnelly, Meghan A; Silver, Robert M

2018-06-01

Magnetic resonance imaging is reported to have good sensitivity and specificity in the diagnosis of placenta accreta spectrum disorders, and is often used as an adjunct to ultrasound. But the additional utility of obtaining magnetic resonance imaging to assist in the clinical management of patients with placenta accreta spectrum disorders, above and beyond the information provided by ultrasound, is unknown. We aimed to determine whether magnetic resonance imaging provides data that may inform clinical management by changing the sonographic diagnosis of placenta accreta spectrum disorders. In all, 78 patients with sonographic evidence or clinical suspicion of placenta accreta spectrum underwent magnetic resonance imaging of the abdomen and pelvis in orthogonal planes through the uterus utilizing T1- and T2-weighted imaging sequences at the University of Utah and the University of Colorado from 1997 through 2017. The magnetic resonance imaging was interpreted by radiologists with expertise in diagnosis of placenta accreta spectrum who had knowledge of the sonographic interpretation and clinical risk factors for placenta accreta spectrum disorders. The primary outcome was a change in diagnosis from sonographic interpretation that could alter clinical management, which was defined a priori. Diagnostic accuracy was verified by surgical and histopathologic diagnosis at the time of delivery. A change in diagnosis that could potentially alter clinical management occurred in 28 (36%) cases. Magnetic resonance imaging correctly changed the diagnosis in 15 (19%), and correctly confirmed the diagnosis in 34 (44%), but resulted in an incorrect change in diagnosis in 13 (17%), and an incorrect confirmation of ultrasound diagnosis in 15 (21%). Magnetic resonance imaging was not more likely to change a diagnosis in the 24 cases of posterior and lateral placental location compared to anterior location (33% vs 37%, P = .84). Magnetic resonance imaging resulted in overdiagnosis in

Magnetic Resonance Imaging of Benign and Malignant Uterine Neoplasms.

PubMed

Leursen, Gustavo; Gardner, Carly Susan; Sagebiel, Tara; Patnana, Madhavi; de CastroFaria, Silvana; Devine, Catherine E; Bhosale, Priya R

2015-08-01

Benign and malignant uterine masses can be seen in the women. Some of these are asymptomatic and incidentally discovered, whereas others can be symptomatic. With the soft tissue contrast resolution magnetic resonance imaging can render a definitive diagnosis, which can further help streamline patient management. In this article we show magnetic resonance imaging examples of benign and malignant masses of the uterus and their treatment strategies. Published by Elsevier Inc.

Diagnosis of endolymphatic hydrops by means of 3T magnetic resonance imaging after intratympanic administration of gadolinium.

PubMed

Tuñón Gómez, M; Lobo Duro, D R; Brea Álvarez, B; García-Berrocal, J R

To detect and graduate endolymphatic hydrops or endolymphatic space dilations in patients with suspected Meniere's disease or immune-mediated inner ear disease by magnetic resonance imaging. A prospective study was performed including all the patients with clinical suspicion of Meniere's disease or immune-mediated inner ear disease treated at the Otolaryngology department during a one year period. In all cases, magnetic resonance imaging (MRI) was performed in a 3T scanner. IR sequence was performed after 24 to 28h prior intratimpanic injection of gadolinium on both ears. Two neurorradiologist graduated endolymphatic space volume as agreed on normal, moderate and significant in the obtained images. The presence of hydrops was documented by MRI in six patients with definite or probable Meniere's disease. In two of the four cases without vertigo hydrops was not demonstrated. In the other two cases with a high clinical suspicion of immune-mediated disease but with negative autoimmune tests hydrops was proved. There was only disagreement on cochlear hydrops presence on two patients. The detection of endolymphatic hydrops in patients with definite or probable Meniere's disease served to confirm the final diagnosis. Moreover, hydrops was detected in patients with suspected immune-mediated inner ear disease, which could have an impact on the diagnosis and treatment of these patients. Therefore, we suggest that this test could be included for the diagnosis of these inner ear diseases. Copyright © 2016 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Magnetic Resonance Imaging of Liver Metastasis.

PubMed

Karaosmanoglu, Ali Devrim; Onur, Mehmet Ruhi; Ozmen, Mustafa Nasuh; Akata, Deniz; Karcaaltincaba, Musturay

2016-12-01

Liver magnetic resonance imaging (MRI) is becoming the gold standard in liver metastasis detection and treatment response assessment. The most sensitive magnetic resonance sequences are diffusion-weighted images and hepatobiliary phase images after Gd-EOB-DTPA. Peripheral ring enhancement, diffusion restriction, and hypointensity on hepatobiliary phase images are hallmarks of liver metastases. In patients with normal ultrasonography, computed tomography (CT), and positron emission tomography (PET)-CT findings and high clinical suspicion of metastasis, MRI should be performed for diagnosis of unseen metastasis. In melanoma, colon cancer, and neuroendocrine tumor metastases, MRI allows confident diagnosis of treatment-related changes in liver and enables differential diagnosis from primary liver tumors. Focal nodular hyperplasia-like nodules in patients who received platinum-based chemotherapy, hypersteatosis, and focal fat can mimic metastasis. In cancer patients with fatty liver, MRI should be preferred to CT. Although the first-line imaging for metastases is CT, MRI can be used as a problem-solving method. MRI may be used as the first-line method in patients who would undergo curative surgery or metastatectomy. Current limitation of MRI is low sensitivity for metastasis smaller than 3mm. MRI fingerprinting, glucoCEST MRI, and PET-MRI may allow simpler and more sensitive diagnosis of liver metastasis. Copyright © 2016 Elsevier Inc. All rights reserved.

Diffusion weighted magnetic resonance imaging and its recent trend—a survey

PubMed Central

Chilla, Geetha Soujanya; Tan, Cher Heng

2015-01-01

Since its inception in 1985, diffusion weighted magnetic resonance imaging has been evolving and is becoming instrumental in diagnosis and investigation of tissue functions in various organs including brain, cartilage, and liver. Even though brain related pathology and/or investigation remains as the main application, diffusion weighted magnetic resonance imaging (DWI) is becoming a standard in oncology and in several other applications. This review article provides a brief introduction of diffusion weighted magnetic resonance imaging, challenges involved and recent advancements. PMID:26029644

Clinical utility of magnetic resonance imaging and ultrasonography for diagnosis of polycystic ovary syndrome in adolescent girls.

PubMed

Kenigsberg, Lisa E; Agarwal, Chhavi; Sin, Sanghun; Shifteh, Keivan; Isasi, Carmen R; Crespi, Rebecca; Ivanova, Janeta; Coupey, Susan M; Heptulla, Rubina A; Arens, Raanan

2015-11-01

To evaluate ovarian morphology using three-dimensional magnetic resonance imaging (MRI) in adolescent girls with and without polycystic ovary syndrome (PCOS). Also compare the utility of MRI versus ultrasonography (US) for diagnosis of PCOS. Cross-sectional study. Urban academic tertiary-care children's hospital. Thirty-nine adolescent girls with untreated PCOS and 22 age/body mass index (BMI)-matched controls. Magnetic resonance imaging and/or transvaginal/transabdominal US. Ovarian volume (OV); follicle number per section (FNPS); correlation between OV on MRI and US; proportion of subjects with features of polycystic ovaries (PCOs) on MRI and US. Magnetic resonance imaging demonstrated larger OV and higher FNPS in subjects with PCOS compared with controls. Within the PCOS group, median OV was 11.9 (7.7) cm(3) by MRI compared with 8.8 (7.8) cm(3) by US. Correlation coefficient between OV by MRI and US was 0.701. Due to poor resolution, FNPS could not be determined by US or compared with MRI. The receiver operating characteristic curve analysis for MRI demonstrated that increasing volume cutoffs for PCOs from 10-14 cm(3) increased specificity from 77%-95%. For FNPS on MRI, specificity increased from 82%-98% by increasing cutoffs from ≥ 12 to ≥ 17. Using Rotterdam cutoffs, 91% of subjects with PCOS met PCO criteria on MRI, whereas only 52% met criteria by US. Ultrasonography measures smaller OV than MRI, cannot accurately detect follicle number, and is a poor imaging modality for characterizing PCOs in adolescents with suspected PCOS. For adolescents in whom diagnosis of PCOS remains uncertain after clinical and laboratory evaluation, MRI should be considered as a diagnostic imaging modality. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Magnetic resonance imaging of the fetal brain.

PubMed

Tee, L Mf; Kan, E Yl; Cheung, J Cy; Leung, W C

2016-06-01

This review covers the recent literature on fetal brain magnetic resonance imaging, with emphasis on techniques, advances, common indications, and safety. We conducted a search of MEDLINE for articles published after 2010. The search terms used were "(fetal OR foetal OR fetus OR foetus) AND (MR OR MRI OR [magnetic resonance]) AND (brain OR cerebral)". Consensus statements from major authorities were also included. As a result, 44 relevant articles were included and formed the basis of this review. One major challenge is fetal motion that is largely overcome by ultra-fast sequences. Currently, single-shot fast spin-echo T2-weighted imaging remains the mainstay for motion resistance and anatomical delineation. Recently, a snap-shot inversion recovery sequence has enabled robust T1-weighted images to be obtained, which is previously a challenge for standard gradient-echo acquisitions. Fetal diffusion-weighted imaging, diffusion tensor imaging, and magnetic resonance spectroscopy are also being developed. With multiplanar capabilities, superior contrast resolution and field of view, magnetic resonance imaging does not have the limitations of sonography, and can provide additional important information. Common indications include ventriculomegaly, callosum and posterior fossa abnormalities, and twin complications. There are safety concerns about magnetic resonance-induced heating and acoustic damage but current literature showed no conclusive evidence of deleterious fetal effects. The American College of Radiology guideline states that pregnant patients can be accepted to undergo magnetic resonance imaging at any stage of pregnancy if risk-benefit ratio to patients warrants that the study be performed. Magnetic resonance imaging of the fetal brain is a safe and powerful adjunct to sonography in prenatal diagnosis. It can provide additional information that aids clinical management, prognostication, and counselling.

Magnetic Resonance Imaging

MedlinePlus

... specific information about your own examination. What is magnetic resonance imaging (MRI)? What is MRI used for? How safe ... What is the MRI examination like? What is magnetic resonance imaging (MRI)? MRI, or magnetic resonance imaging, is a ...

Association of magnetic resonance imaging findings and histologic diagnosis in dogs with nasal disease: 78 cases (2001-2004).

PubMed

Miles, Macon S; Dhaliwal, Ravinder S; Moore, Michael P; Reed, Ann L

2008-06-15

OBJECTIVE-To determine whether magnetic resonance imaging (MRI) features correlated with histologic diagnosis in dogs with nasal disease. DESIGN-Retrospective case series. ANIMALS-78 Dogs undergoing MRI for evaluation of nasal disease. PROCEDURES-Medical records and MRI reports of dogs were reviewed to identify MRI features associated with histologic diagnosis. Features evaluated were presence of a mass effect, frontal sinus involvement, sphenoid sinus involvement, maxillary recess involvement, nasopharyngeal infiltration by soft tissue, nasal turbinate destruction, vomer bone lysis, paranasal bone destruction, cribriform plate erosion, and lesion extent (ie, unilateral vs bilateral). RESULTS-33 Dogs had neoplastic disease, 38 had inflammatory rhinitis, and 7 had fungal rhinitis. Lesion extent was not significantly associated with histologic diagnosis. Absence of a mass effect was significantly associated with inflammatory disease. However, presence of a mass was not specific for neoplasia. In dogs with evidence of a mass on magnetic resonance (MR) images, nasal turbinate destruction, frontal sinus invasion, and maxillary recess invasion were not useful in distinguishing neoplastic from nonneoplastic disease, but cribriform plate erosion, vomer bone lysis, paranasal bone destruction, sphenoid sinus invasion, and nasopharyngeal invasion were. CONCLUSIONS AND CLINICAL RELEVANCE-Results suggested that in dogs with nasal disease, the lack of a mass effect on MR images was significantly associated with inflammatory disease. In dogs with a mass effect on MR images, vomer bone lysis, cribriform plate erosion, paranasal bone destruction, sphenoid sinus invasion by a mass, and nasopharyngeal invasion by a mass were significantly associated with a diagnosis of neoplasia.

Diagnosis and quantification of the iron overload through Magnetic resonance.

PubMed

Alústiza Echeverría, J M; Barrera Portillo, M C; Guisasola Iñiguiz, A; Ugarte Muño, A

There are different magnetic resonance techniques and models to quantify liver iron concentration. T2 relaxometry methods evaluate the iron concentration in the myocardium, and they are able to discriminate all the levels of iron overload in the liver. Signal intensity ratio methods saturate with high levels of liver overload and can not assess iron concentration in the myocardium but they are more accessible and are very standardized. This article reviews, in different clinical scenarios, when Magnetic Resonance must be used to assess iron overload in the liver and myocardium and analyzes the current challenges to optimize the aplication of the technique and to be it included in the clinical guidelines. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Magnetic resonance imaging of spinal infection.

PubMed

Tins, Bernhard J; Cassar-Pullicino, Victor N; Lalam, Radhesh K

2007-06-01

This article reviews the pathophysiology of spinal infection and its relevance for imaging. Magnetic resonance imaging (MRI) is the modality with by far the best sensitivity and specificity for spinal infection. The imaging appearances of spinal infection in MRI are outlined, and imaging techniques are discussed. The problems of clinical diagnosis are outlined. There is some emphasis on the MRI differentiation of pyogenic and nonpyogenic infection and on the differential diagnosis of spinal infection centered on the imaging presentation.

Diagnosis of Gastroesophageal Reflux Disease Using Real-time Magnetic Resonance Imaging

PubMed Central

Zhang, Shuo; Joseph, Arun A.; Gross, Lisa; Ghadimi, Michael; Frahm, Jens; Beham, Alexander W.

2015-01-01

A small angle (His angle) between the oesophagus and the fundus of the stomach is considered to act as flap valve and anti-reflux barrier. A wide angle results in dysfunction of the oesophagogastric junction and subsequently in gastroesophageal reflux disease (GERD). Here, we used real-time magnetic resonance imaging (MRI) at 50 ms resolution (20 frames per second) in 12 volunteers and 12 patients with GERD to assess transport of pineapple juice through the oesophagogastric junction and reflux during Valsalva. We found that the intra-abdominal part of the oesophagus was bended towards the left side resulting in an angle of 75.3 ± 17.4, which was significantly larger during Valsava (P = 0.017). Reflux and several underlying pathologies were detected in 11 out of 12 patients. Our data visualize oesophagogastric junction physiology and disprove the flap valve hypothesis. Further, non-invasive real-time MRI has considerable potential for the diagnosis of causative pathologies leading to GERD. PMID:26175205

Magnetic resonance imaging for diagnosis and assessment of cartilage defect repairs.

PubMed

Marlovits, Stefan; Mamisch, Tallal Charles; Vekszler, György; Resinger, Christoph; Trattnig, Siegfried

2008-04-01

Clinical magnetic resonance imaging (MRI) is the method of choice for the non-invasive evaluation of articular cartilage defects and the follow-up of cartilage repair procedures. The use of cartilage-sensitive sequences and a high spatial-resolution technique enables the evaluation of cartilage morphology even in the early stages of disease, as well as assessment of cartilage repair. Sequences that offer high contrast between articular cartilage and adjacent structures, such as the fat-suppressed, 3-dimensional, spoiled gradient-echo sequence and the fast spin-echo sequence, are accurate and reliable for evaluating intrachondral lesions and surface defects of articular cartilage. These sequences can also be performed together in reasonable examination times. In addition to morphology, new MRI techniques provide insight into the biochemical composition of articular cartilage and cartilage repair tissue. These techniques enable the diagnosis of early cartilage degeneration and help to monitor the effect and outcome of various surgical and non-surgical cartilage repair therapies.

Retrospective review of 50 canine nasal tumours evaluated by low-field magnetic resonance imaging.

PubMed

Avner, A; Dobson, J M; Sales, J I; Herrtage, M E

2008-05-01

Low-field magnetic resonance imaging machines are being used more often in veterinary practice for the investigation of sinonasal disease. The aim of this retrospective study was to describe and characterise the low-field magnetic resonance imaging features of nasal tumours in dogs. The Queen's Veterinary School Hospital magnetic resonance imaging database (2001-2005) was searched for dogs with a magnetic resonance imaging diagnosis of a nasal tumour. Fifty cases with histological diagnosis of nasal tumour were found. The appearance and extent of the nasal tumour as well as the involvement of adjacent anatomic structures were examined against a checklist. The most common magnetic resonance imaging findings were as follows. (1) Soft tissue mass replacing the destroyed nasal conchae and/or ethmoturbinates (98 per cent of cases). (2) Nasal septum destruction (68 per cent of cases). (3) Retained secretions with or without mass caudally in frontal sinuses (62 per cent of cases). (4) Nasal/frontal bone destruction (52 per cent of cases). Low-field magnetic resonance imaging allowed differentiation of tumour tissue from retained secretions or necrotic tissue. Magnetic resonance imaging was invaluable in assessing the extension of the tumour into the maxillary recesses, caudal recesses, nasopharynx, adjacent bones and cranial cavity. The tumour often extended caudally into the frontal sinuses, nasopharynx and perhaps most importantly into the caudal recesses. Tumour extension into the cranial cavity was not common (16 per cent), and only three of these cases showed neurological signs. However, 54 per cent of cases showed focal meningeal (dural) hyperintensity, although the significance of this is unclear. A significant difference (P<0.05) in tumour signal intensity between the sarcomas and carcinomas was found. The use of a low-field magnetic resonance imaging technique is excellent for the diagnosis and determination of extent of sinonasal tumours.

Cardiac magnetic resonance radiofrequency tissue tagging for diagnosis of constrictive pericarditis: A proof of concept study.

PubMed

Power, John A; Thompson, Diane V; Rayarao, Geetha; Doyle, Mark; Biederman, Robert W W

2016-05-01

Invasive cardiac catheterization is the venerable "gold standard" for diagnosing constrictive pericarditis. However, its sensitivity and specificity vary dramatically from center to center. Given the ability to unequivocally define segments of the pericardium with the heart via radiofrequency tissue tagging, we hypothesize that cardiac magnetic resonance has the capability to be the new gold standard. All patients who were referred for cardiac magnetic resonance evaluation of constrictive pericarditis underwent cardiac magnetic resonance radiofrequency tissue tagging to define visceral-parietal pericardial adherence to determine constriction. This was then compared with intraoperative surgical findings. Likewise, all preoperative cardiac catheterization testing was reviewed in a blinded manner. A total of 120 patients were referred for clinical suspicion of constrictive pericarditis. Thirty-nine patients were defined as constrictive pericarditis positive solely via radiofrequency tissue-tagging cardiac magnetic resonance, of whom 21 were positive, 4 were negative, and 1 was equivocal for constrictive pericarditis, as defined by cardiac catheterization. Of these patients, 16 underwent pericardiectomy and were surgically confirmed. There was 100% agreement between cardiac magnetic resonance-defined constrictive pericarditis positivity and postsurgical findings. No patients were misclassified by cardiac magnetic resonance. In regard to the remaining constrictive pericarditis-positive patients defined by cardiac magnetic resonance, 10 were treated medically, declined, were ineligible for surgery, or were lost to follow-up. Long-term follow-up of those who were constrictive pericarditis negative by cardiac magnetic resonance showed no early or late crossover to the surgery arm. Cardiac magnetic resonance via radiofrequency tissue tagging offers a unique, efficient, and effective manner of defining clinically and surgically relevant constrictive pericarditis

Cardiac Magnetic Resonance Imaging for the Diagnosis of Coronary Artery Disease

PubMed Central

2010-01-01

Executive Summary In July 2009, the Medical Advisory Secretariat (MAS) began work on Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease (CAD), an evidence-based review of the literature surrounding different cardiac imaging modalities to ensure that appropriate technologies are accessed by patients suspected of having CAD. This project came about when the Health Services Branch at the Ministry of Health and Long-Term Care asked MAS to provide an evidentiary platform on effectiveness and cost-effectiveness of non-invasive cardiac imaging modalities. After an initial review of the strategy and consultation with experts, MAS identified five key non-invasive cardiac imaging technologies for the diagnosis of CAD. Evidence-based analyses have been prepared for each of these five imaging modalities: cardiac magnetic resonance imaging, single photon emission computed tomography, 64-slice computed tomographic angiography, stress echocardiography, and stress echocardiography with contrast. For each technology, an economic analysis was also completed (where appropriate). A summary decision analytic model was then developed to encapsulate the data from each of these reports (available on the OHTAC and MAS website). The Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease series is made up of the following reports, which can be publicly accessed at the MAS website at: www.health.gov.on.ca/mas or at www.health.gov.on.ca/english/providers/program/mas/mas_about.html Single Photon Emission Computed Tomography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Stress Echocardiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Stress Echocardiography with Contrast for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis 64-Slice Computed Tomographic Angiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Cardiac

Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging.

ERIC Educational Resources Information Center

Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

2000-01-01

Describes a set of simple, inexpensive, classical demonstrations of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) principles that illustrate the resonance condition associated with magnetic dipoles and the dependence of the resonance frequency on environment. (WRM)

Magnetic resonance appearance of monoclonal gammopathies of unknown significance and multiple myeloma. The GRI Study Group.

PubMed

Bellaïche, L; Laredo, J D; Lioté, F; Koeger, A C; Hamze, B; Ziza, J M; Pertuiset, E; Bardin, T; Tubiana, J M

1997-11-01

A prospective multicenter study. To evaluate the use of magnetic resonance imaging, in the differentiation between monoclonal gammopathies of unknown significance and multiple myeloma. Although multiple myeloma has been studied extensively with magnetic resonance imaging, to the authors' knowledge, no study has evaluated the clinical interest of magnetic resonance imaging in the differentiation between monoclonal gammopathies of unknown significance and multiple myeloma. The magnetic resonance examinations of the thoracolumbar spine in 24 patients with newly diagnosed monoclonal gammopathies of unknown significance were compared with those performed in 44 patients with newly diagnosed nontreated multiple myeloma. All findings on magnetic resonance examination performed in patients with monoclonal gammopathies of unknown significance were normal, whereas findings on 38 (86%) of the 44 magnetic resonance examinations performed in patients with multiple myeloma were abnormal. Magnetic resonance imaging can be considered as an additional diagnostic tool in differentiating between monoclonal gammopathies of unknown significance and multiple myeloma, which may be helpful when routine criteria are not sufficient. An abnormal finding on magnetic resonance examination in a patient with monoclonal gammopathies of unknown significance should suggest the diagnosis of multiple myeloma after other causes of marrow signal abnormalities are excluded. Magnetic resonance imaging also may be proposed in the long-term follow-up of monoclonal gammopathies of unknown significance when a new biologic or clinical event suggests the diagnosis of malignant monoclonal gammopathy.

Magnetic resonance imaging findings of cellular angiofibroma of the tunica vaginalis of the testis: a case report.

PubMed

Ntorkou, Alexandra A; Tsili, Athina C; Giannakis, Dimitrios; Batistatou, Anna; Stavrou, Sotirios; Sofikitis, Nikolaos; Argyropoulou, Maria I

2016-03-31

Cellular angiofibroma represents a rare mesenchymal tumor typically involving the inguinoscrotal area in middle-aged men. Although the origin of this benign tumor is unknown, it is histologically classified as an angiomyxoid tumor. Cellular angiofibroma is characterized by a diversity of pathological and imaging features. An accurate preoperative diagnosis is challenging. Magnetic resonance imaging examination of the scrotum has been reported as a valuable adjunct modality in the investigation of scrotal pathology. The technique by providing both structural and functional information is useful in the differentiation between extratesticular and intratesticular diseases and in the preoperative characterization of the histologic nature of various scrotal lesions. There are few reports in the English literature addressing the magnetic resonance imaging findings of cellular angiofibroma of the scrotum and no reports on functional magnetic resonance imaging data. Here we present the first case of a cellular angiofibroma arising from the tunica vaginalis of the testis and we discuss the value of a multiparametric magnetic resonance protocol, including diffusion-weighted imaging, magnetization transfer imaging and dynamic contrast-enhanced magnetic resonance imaging in the preoperative diagnosis of this rare neoplasm. A 47-year Greek man presented with a painless left scrotal swelling, which had gradually enlarged during the last 6 months. Magnetic resonance imaging of his scrotum displayed a left paratesticular mass, in close proximity to the tunica vaginalis, with heterogeneous high signal intensity on T2-weighted images and no areas of restricted diffusion. The tumor was hypointense on magnetization transfer images, suggestive for the presence of macromolecules. On dynamic contrast-enhanced magnetic resonance imaging the mass showed intense heterogeneous enhancement with a type II curve. Magnetic resonance imaging findings were strongly suggestive of a benign

Important advances in technology and unique applications related to cardiac magnetic resonance imaging.

PubMed

Ghosn, Mohamad G; Shah, Dipan J

2014-01-01

Cardiac magnetic resonance has become a well-established imaging modality and is considered the gold standard for myocardial tissue viability assessment and ventricular volumes quantification. Recent technological hardware and software advancements in magnetic resonance imaging technology have allowed the development of new methods that can improve clinical cardiovascular diagnosis and prognosis. The advent of a new generation of higher magnetic field scanners can be beneficial to various clinical applications. Also, the development of faster acquisition techniques have allowed mapping of the magnetic relaxation properties T1, T2, and T2* in the myocardium that can be used to quantify myocardial diffuse fibrosis, determine the presence of edema or inflammation, and measure iron within the myocardium, respectively. Another recent major advancement in CMR has been the introduction of three-dimension (3D) phase contrast imaging, also known as 4D flow. The following review discusses key advances in cardiac magnetic resonance technology and their potential to improve clinical cardiovascular diagnosis and outcomes.

Identification of disappearing brain lesions with intraoperative magnetic resonance imaging prevents surgery.

PubMed

Sutherland, Christina S; Kelly, John Jp; Morrish, William; Sutherland, Garnette R

2010-10-01

Typically, neurosurgery is performed several weeks after diagnostic imaging. In the majority of cases, histopathology confirms the diagnosis of neoplasia. In a small number of cases, a different diagnosis is established or histopathology is nondiagnostic. The frequency with which these outcomes occur has not been established. To determine the frequency and outcome of disappearing brain lesions within a group of patients undergoing surgery for suspected brain tumor. Over the past decade, 982 patients were managed in the intraoperative magnetic resonance imaging unit at the University of Calgary, Calgary, Alberta, Canada. These patients have been prospectively evaluated. In 652 patients, a brain tumor was suspected. In 6 of the 652 patients, histopathology indicated a nontumor diagnosis. In 5 patients, intraoperative images, acquired after induction of anesthesia, showed complete or nearly complete resolution of the suspected tumor identified on diagnostic magnetic resonance imaging acquired 6 ± 4 (mean ± SD) weeks previously. Anesthesia was reversed, and the surgical procedure aborted. The lesions have not progressed with 6 ± 2 years of follow-up. Intraoperative magnetic resonance imaging prevented surgery on 5 patients with disappearing lesions.

Enhancing malaria diagnosis through microfluidic cell enrichment and magnetic resonance relaxometry detection

NASA Astrophysics Data System (ADS)

Fook Kong, Tian; Ye, Weijian; Peng, Weng Kung; Wei Hou, Han; Marcos; Preiser, Peter Rainer; Nguyen, Nam-Trung; Han, Jongyoon

2015-06-01

Despite significant advancements over the years, there remains an urgent need for low cost diagnostic approaches that allow for rapid, reliable and sensitive detection of malaria parasites in clinical samples. Our previous work has shown that magnetic resonance relaxometry (MRR) is a potentially highly sensitive tool for malaria diagnosis. A key challenge for making MRR based malaria diagnostics suitable for clinical testing is the fact that MRR baseline fluctuation exists between individuals, making it difficult to detect low level parasitemia. To overcome this problem, it is important to establish the MRR baseline of each individual while having the ability to reliably determine any changes that are caused by the infection of malaria parasite. Here we show that an approach that combines the use of microfluidic cell enrichment with a saponin lysis before MRR detection can overcome these challenges and provide the basis for a highly sensitive and reliable diagnostic approach of malaria parasites. Importantly, as little as 0.0005% of ring stage parasites can be detected reliably, making this ideally suited for the detection of malaria parasites in peripheral blood obtained from patients. The approaches used here are envisaged to provide a new malaria diagnosis solution in the near future.

Magnetic resonance imaging of diabetic foot complications

PubMed Central

Low, Keynes TA; Peh, Wilfred CG

2015-01-01

This pictorial review aims to illustrate the various manifestations of the diabetic foot on magnetic resonance (MR) imaging. The utility of MR imaging and its imaging features in the diagnosis of pedal osteomyelitis are illustrated. There is often difficulty encountered in distinguishing osteomyelitis from neuroarthropathy, both clinically and on imaging. By providing an accurate diagnosis based on imaging, the radiologist plays a significant role in the management of patients with complications of diabetic foot. PMID:25640096

Magnetic Resonance Elastography and Other Magnetic Resonance Imaging Techniques in Chronic Liver Disease: Current Status and Future Directions.

PubMed

Tan, Cher Heng; Venkatesh, Sudhakar Kundapur

2016-09-15

Recent advances in the noninvasive imaging of chronic liver disease have led to improvements in diagnosis, particularly with magnetic resonance imaging (MRI). A comprehensive evaluation of the liver may be performed with the quantification of the degree of hepatic steatosis, liver iron concentration, and liver fibrosis. In addition, MRI of the liver may be used to identify complications of cirrhosis, including portal hypertension, ascites, and the development of hepatocellular carcinoma. In this review article, we discuss the state of the art techniques in liver MRI, namely, magnetic resonance elastography, hepatobiliary phase MRI, and liver fat and iron quantification MRI. The use of these advanced techniques in the management of chronic liver diseases, including nonalcoholic fatty liver disease, will be elaborated.

Magnetic Resonance Elastography and Other Magnetic Resonance Imaging Techniques in Chronic Liver Disease: Current Status and Future Directions

PubMed Central

Tan, Cher Heng; Venkatesh, Sudhakar Kundapur

2016-01-01

Recent advances in the noninvasive imaging of chronic liver disease have led to improvements in diagnosis, particularly with magnetic resonance imaging (MRI). A comprehensive evaluation of the liver may be performed with the quantification of the degree of hepatic steatosis, liver iron concentration, and liver fibrosis. In addition, MRI of the liver may be used to identify complications of cirrhosis, including portal hypertension, ascites, and the development of hepatocellular carcinoma. In this review article, we discuss the state of the art techniques in liver MRI, namely, magnetic resonance elastography, hepatobiliary phase MRI, and liver fat and iron quantification MRI. The use of these advanced techniques in the management of chronic liver diseases, including non-alcoholic fatty liver disease, will be elaborated. PMID:27563019

Iron overload in a teenager with xerocytosis: the importance of nuclear magnetic resonance imaging.

PubMed

Assis, Reijâne Alves de; Kassab, Carolina; Seguro, Fernanda Salles; Costa, Fernando Ferreira; Silveira, Paulo Augusto Achucarro; Wood, John; Hamerschlak, Nelson

2013-12-01

To report a case of iron overload secondary to xerocytosis, a rare disease in a teenager, diagnosed, by T2* magnetic resonance imaging. We report the case of a symptomatic patient with xerocytosis, a ferritin level of 350ng/mL and a significant cardiac iron overload. She was diagnosed by T2* magnetic resonance imaging and received chelation therapy Ektacytometric analysis confirmed the diagnosis of hereditary xerocytosis. Subsequent T2* magnetic resonance imaging demonstrated complete resolution of the iron overload in various organs, as a new echocardiography revealed a complete resolution of previous cardiac alterations. The patient remains in chelation therapy. Xerocytosis is a rare autosomal dominant genetic disorder characterized by dehydrated stomatocytosis. The patient may present with intense fatigue and iron overload. We suggest the regular use of T2* magnetic resonance imaging for the diagnosis and control of the response to iron chelation in xerocytosis, and we believe it can be used also in other hemolytic anemia requiring transfusions.

Magnetic resonance imaging of chemistry.

PubMed

Britton, Melanie M

2010-11-01

Magnetic resonance imaging (MRI) has long been recognized as one of the most important tools in medical diagnosis and research. However, MRI is also well placed to image chemical reactions and processes, determine the concentration of chemical species, and look at how chemistry couples with environmental factors, such as flow and heterogeneous media. This tutorial review will explain how magnetic resonance imaging works, reviewing its application in chemistry and its ability to directly visualise chemical processes. It will give information on what resolution and contrast are possible, and what chemical and physical parameters can be measured. It will provide examples of the use of MRI to study chemical systems, its application in chemical engineering and the identification of contrast agents for non-clinical applications. A number of studies are presented including investigation of chemical conversion and selectivity in fixed-bed reactors, temperature probes for catalyst pellets, ion mobility during tablet dissolution, solvent dynamics and ion transport in Nafion polymers and the formation of chemical waves and patterns.

Nuclear magnetic resonance diagnosis of an anaplastic astrocytoma.

PubMed

Jackson, J A; Derman, H S; Harper, R L; Willcott, M R; Ford, J J; Schneiders, N J; McCrary, J A; Kelly, A; Bryan, R N

1984-01-01

A patient presented with an 8-month history of a progressive left homonymous visual field deficit, left hemiparesis, and a left thalamocortical sensory deficit that was not detectable by repeated conventional neurodiagnostic evaluations. Proton nuclear magnetic resonance (NMR) imaging revealed a right parietal lesion characterized by a prolonged T2 (spin-spin relaxation time). At surgery, the mass proved to be an anaplastic astrocytoma. NMR appears to be more sensitive than x-ray computerized tomography scanning in some patients with malignant gliomas and offers the clinician an additional probe with which to evaluate these patients.

[Comparison of the accuracy of rectal endoscopic sonography and magnetic resonance imaging in the diagnosis of colorectal endometriosis].

PubMed

Kanté, F; Belghiti, J; Roseau, G; Thomassin-Naggara, I; Bazot, M; Daraï, E; Ballester, M

2017-03-01

To compare the accuracy of magnetic resonance imaging (MRI) and rectal endoscopic sonography (RES) for the diagnosis of colorectal endometriosis. In retrospective study, 407 patients operated on service of gynecology of Tenon hospital for deep endometriosis with suspected colorectal involvement. All patients underwent MRI and then RES. In the study, 239 patients (59%) had colorectal endometriosis which were diagnosed with the histology. The sensitivity, specificity, positive and negative predictive value (PPV and NPV) of RES and MRI for the diagnosis of colorectal endometriosis were respectively 92%, 87%, 91%, 88% and 85%, 88%, 91%, 80%. The accuracy of RES was not significantly different than MRI (90% versus 86%, P=0.09). RES is a good exam to diagnose colorectal endometriosis. It is able to improve diagnosis performances. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Proton magnetic resonance spectroscopy of tubercular breast abscess: report of a case.

PubMed

Das, Chandan Jyoti; Medhi, Kunjahari

2008-01-01

In vivo proton magnetic resonance spectroscopy (H-MRS) is a functional imaging modality. When magnetic resonance imaging is coupled with H-MRS, it results in accurate metabolic characterization of various lesions. Proton magnetic resonance spectroscopy has an established role in evaluating malignant breast lesions, and the increasing number of published literature supports the role of H-MRS in patients with breast cancer. However, H-MRS can be of help in evaluating benign breast disease. We present a case of tubercular breast abscess, initial diagnosis of which was suggested based on characteristic lipid pick on H-MRS and was subsequently confirmed by fine needle aspiration biopsy of the breast lesion.

[Magnetic resonance imaging of brain tumors].

PubMed

Prayer, Daniela; Brugger, P C

2002-01-01

Investigating intracranial tumors, different MR-related methods permit not only morphological visualization of lesions but also give insights into their metabolism, resulting in information about the biological qualities of the respective tumor. Magnetic resonance protocols are selected based on the type and timing of onset of clinical signs. Combined information from imaging studies and spectroscopy facilitates the differential diagnosis between blastomatous and non-blastomatous lesions before and after therapy.

Magnetic resonance conditional paramagnetic choke for suppression of imaging artifacts during magnetic resonance imaging.

PubMed

Wu, Kevin J; Gregory, T Stan; Boland, Brian L; Zhao, Wujun; Cheng, Rui; Mao, Leidong; Tse, Zion Tsz Ho

2018-06-01

Higher risk patient populations require continuous physiological monitoring and, in some cases, connected life-support systems, during magnetic resonance imaging examinations. While recently there has been a shift toward wireless technology, some of the magnetic resonance imaging devices are still connected to the outside using cabling that could interfere with the magnetic resonance imaging's radio frequency during scanning, resulting in excessive heating. We developed a passive method for radio frequency suppression on cabling that may assist in making some of these devices magnetic resonance imaging compatible. A barrel-shaped strongly paramagnetic choke was developed to suppress induced radio frequency signals which are overlaid onto physiological monitoring leads during magnetic resonance imaging. It utilized a choke placed along the signal lines, with a gadolinium solution core. The choke's magnetic susceptibility was modeled, for a given geometric design, at increasing chelate concentration levels, and measured using a vibrating sample magnetometer. Radio frequency noise suppression versus frequency was quantified with network-analyzer measurements and tested using cabling placed in the magnetic resonance imaging scanner. Temperature-elevation and image-quality reduction due to the device were measured using American Society for Testing and Materials phantoms. Prototype chokes with gadolinium solution cores exhibited increasing magnetic susceptibility, and insertion loss (S21) also showed higher attenuation as gadolinium concentration increased. Image artifacts extending <4 mm from the choke were observed during magnetic resonance imaging, which agreed well with the predicted ∼3 mm artifact from the electrochemical machining simulation. An accompanying temperature increase of <1 °C was observed in the magnetic resonance imaging phantom trial. An effective paramagnetic choke for radio frequency suppression during magnetic resonance imaging was developed

Cardiac magnetic resonance in myocardial disease.

PubMed

Sechtem, U; Mahrholdt, H; Vogelsberg, H

2007-12-01

For a number of patients it is difficult to diagnose the cause of cardiac disease. In such patients cardiac magnetic resonance is useful for helping to make a differential diagnosis between ischaemic and dilated cardiomyopathy; identifying patients with myocarditis; diagnosing cardiac involvement in sarcoidosis and Chagas' disease; identifying patients with unusual forms of hypertrophic cardiomyopathy and those with continuing myocardial damage; and defining the sequelae of ablation treatment for hypertrophic obstructive cardiomyopathy.

Role of proton magnetic resonance spectroscopy in the diagnosis of gliomatosis cerebri: a unique pattern of normal choline but elevated Myo-inositol metabolite levels.

PubMed

Mohana-Borges, Aurea V R; Imbesi, Steven G; Dietrich, Rosalind; Alksne, John; Amjadi, Darius K

2004-01-01

A patient with histologically proven gliomatosis cerebri presented with a normal choline level but a markedly abnormal elevated myo-inositol level on magnetic resonance (MR) spectroscopy. We describe the case presentation, imaging findings (in particular, the unique MR spectroscopic pattern), and their significance regarding the diagnosis of this relatively rare neoplasm.

Diagnosis of deep endometriosis: clinical examination, ultrasonography, magnetic resonance imaging, and other techniques.

PubMed

Bazot, Marc; Daraï, Emile

2017-12-01

The aim of the present review was to evaluate the contribution of clinical examination and imaging techniques, mainly transvaginal sonography and magnetic resonance imaging (MRI) to diagnose deep infiltrating (DE) locations using prisma statement recommendations. Clinical examination has a relative low sensitivity and specificity to diagnose DE. Independently of DE locations, for all transvaginal sonography techniques a pooled sensitivity and specificity of 79% and 94% are observed approaching criteria for a triage test. Whatever the protocol and MRI devices, the pooled sensitivity and specificity for pelvic endometriosis diagnosis were 94% and 77%, respectively. For rectosigmoid endometriosis, pooled sensitivity and specificity of MRI were 92% and 96%, respectively fulfilling criteria of replacement test. In conclusion, advances in imaging techniques offer high sensitivity and specificity to diagnose DE with at least triage value and for rectosigmoid endometriosis replacement value imposing a revision of the concept of laparoscopy as the gold standard. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Diagnostic value of three-dimensional magnetic resonance imaging of inner ear after intratympanic gadolinium injection, and clinical application of magnetic resonance imaging scoring system in patients with delayed endolymphatic hydrops.

PubMed

Gu, X; Fang, Z-M; Liu, Y; Lin, S-L; Han, B; Zhang, R; Chen, X

2014-01-01

Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging of the inner ear after intratympanic injection of gadolinium, together with magnetic resonance imaging scoring of the perilymphatic space, were used to investigate the positive identification rate of hydrops and determine the technique's diagnostic value for delayed endolymphatic hydrops. Twenty-five patients with delayed endolymphatic hydrops underwent pure tone audiometry, bithermal caloric testing, vestibular-evoked myogenic potential testing and three-dimensional magnetic resonance imaging of the inner ear after bilateral intratympanic injection of gadolinium. The perilymphatic space of the scanned images was analysed to investigate the positive identification rate of endolymphatic hydrops. According to the magnetic resonance imaging scoring of the perilymphatic space and the diagnostic standard, 84 per cent of the patients examined had endolymphatic hydrops. In comparison, the positive identification rates for vestibular-evoked myogenic potential and bithermal caloric testing were 52 per cent and 72 per cent respectively. Three-dimensional magnetic resonance imaging after intratympanic injection of gadolinium is valuable in the diagnosis of delayed endolymphatic hydrops and its classification. The perilymphatic space scoring system improved the diagnostic accuracy of magnetic resonance imaging.

Utility of Magnetic Resonance Imaging for the Diagnosis of Appendicitis During Pregnancy: A Canadian Experience.

PubMed

Burns, Michael; Hague, Cameron J; Vos, Patrick; Tiwari, Pari; Wiseman, Sam M

2017-11-01

The objective of the study was to evaluate the performance of magnetic resonance imaging (MRI) for the diagnosis of appendicitis during pregnancy. We conducted a retrospective review of all MRI scans performed at our institution, between 2006 and 2012, for the evaluation of suspected appendicitis in pregnant women. Details of the MRI scans performed were obtained from the radiology information system as well as details of any ultrasounds carried out for the same indication. Clinical and pathological data were obtained by retrospective chart review. The study population comprised 63 patients, and 8 patients underwent a second MRI scan during the same pregnancy. A total of 71 MRI scans were reviewed. The appendix was identified on 40 scans (56.3%). Sensitivity of MRI was 75% and specificity was 100% for the diagnosis of appendicitis in pregnant women. When cases with right lower quadrant inflammatory fat stranding or focal fluid, without appendix visualization, were classified as positive for appendicitis, MRI sensitivity increased to 81.3% but specificity decreased to 96.4%. MRI is sensitive and highly specific for the diagnosis of appendicitis during pregnancy and should be considered as a first line imaging study for this clinical presentation. Copyright © 2017 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Magnetic nanoparticles in magnetic resonance imaging and diagnostics.

PubMed

Rümenapp, Christine; Gleich, Bernhard; Haase, Axel

2012-05-01

Magnetic nanoparticles are useful as contrast agents for magnetic resonance imaging (MRI). Paramagnetic contrast agents have been used for a long time, but more recently superparamagnetic iron oxide nanoparticles (SPIOs) have been discovered to influence MRI contrast as well. In contrast to paramagnetic contrast agents, SPIOs can be functionalized and size-tailored in order to adapt to various kinds of soft tissues. Although both types of contrast agents have a inducible magnetization, their mechanisms of influence on spin-spin and spin-lattice relaxation of protons are different. A special emphasis on the basic magnetism of nanoparticles and their structures as well as on the principle of nuclear magnetic resonance is made. Examples of different contrast-enhanced magnetic resonance images are given. The potential use of magnetic nanoparticles as diagnostic tracers is explored. Additionally, SPIOs can be used in diagnostic magnetic resonance, since the spin relaxation time of water protons differs, whether magnetic nanoparticles are bound to a target or not.

Magnetic resonance fingerprinting.

PubMed

Ma, Dan; Gulani, Vikas; Seiberlich, Nicole; Liu, Kecheng; Sunshine, Jeffrey L; Duerk, Jeffrey L; Griswold, Mark A

2013-03-14

Magnetic resonance is an exceptionally powerful and versatile measurement technique. The basic structure of a magnetic resonance experiment has remained largely unchanged for almost 50 years, being mainly restricted to the qualitative probing of only a limited set of the properties that can in principle be accessed by this technique. Here we introduce an approach to data acquisition, post-processing and visualization--which we term 'magnetic resonance fingerprinting' (MRF)--that permits the simultaneous non-invasive quantification of multiple important properties of a material or tissue. MRF thus provides an alternative way to quantitatively detect and analyse complex changes that can represent physical alterations of a substance or early indicators of disease. MRF can also be used to identify the presence of a specific target material or tissue, which will increase the sensitivity, specificity and speed of a magnetic resonance study, and potentially lead to new diagnostic testing methodologies. When paired with an appropriate pattern-recognition algorithm, MRF inherently suppresses measurement errors and can thus improve measurement accuracy.

Added value of cardiac magnetic resonance in etiological diagnosis of ventricular arrhythmias.

PubMed

Cabanelas, Nuno; Vidigal Ferreira, Maria João; Donato, Paulo; Gaspar, António; Pinto, Joana; Caseiro-Alves, Filipe; Providência, Luís Augusto

2013-10-01

Cardiac magnetic resonance (CMR) imaging is increasingly important in the diagnostic work-up of a wide range of heart diseases, including those with arrhythmogenic potential. To assess the added value of CMR in etiological diagnosis of ventricular arrhythmias after an inconclusive conventional investigation. Patients undergoing CMR between 2005 and 2011 for investigation of ventricular arrhythmias were included (n=113). All had documented arrhythmias. Those with a definite diagnosis from a previous investigation and those with evidence of coronary artery disease (acute coronary syndrome, typical angina symptoms, increase in biomarkers or positive stress test) were excluded. CMR results were considered relevant when they fulfilled diagnostic criteria. Of the 113 patients, 57.5% were male and mean age was 41.7 ± 16.2 years. Regarding the initial arrhythmia, 38.1% had ventricular fibrillation/sustained ventricular tachycardia (VF/VT) and 61.9% had less complex ventricular ectopy. CMR imaging showed criteria of a specific diagnosis in 42.5% of patients, was totally normal in 36.3%, and showed non-specific alterations in the remainder. In VF/VT patients, specific criteria were found in 60.4%, and in 31.4% of those with less complex ectopy. The most frequent diagnoses were arrhythmogenic right ventricular dysplasia, ventricular non-compaction and myopericarditis. It is worth noting that, although there was no evidence of previous coronary artery disease, 6.2% of patients had a late gadolinium enhancement distribution pattern compatible with myocardial infarction. CMR gives additional and important information in the diagnostic work-up of ventricular arrhythmias after an inconclusive initial investigation. The proportion of patients with diagnostic criteria was 42.5% (60.0% in those with VF/VT), and CMR was completely normal in 36.6%. Copyright © 2012 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Correlation between Clinical Features and Magnetic Resonance Imaging Findings in Lumbar Disc Prolapse.

PubMed

Thapa, S S; Lakhey, R B; Sharma, P; Pokhrel, R K

2016-05-01

Magnetic resonance imaging is routinely done for diagnosis of lumbar disc prolapse. Many abnormalities of disc are observed even in asymptomatic patient.This study was conducted tocorrelate these abnormalities observed on Magnetic resonance imaging and clinical features of lumbar disc prolapse. A This prospective analytical study includes 57 cases of lumbar disc prolapse presenting to Department of Orthopedics, Tribhuvan University Teaching Hospital from March 2011 to August 2012. All patientshad Magnetic resonance imaging of lumbar spine and the findings regarding type, level and position of lumbar disc prolapse, any neural canal or foraminal compromise was recorded. These imaging findings were then correlated with clinical signs and symptoms. Chi-square test was used to find out p-value for correlation between clinical features and Magnetic resonance imaging findings using SPSS 17.0. This study included 57 patients, with mean age 36.8 years. Of them 41(71.9%) patients had radicular leg pain along specific dermatome. Magnetic resonance imaging showed 104 lumbar disc prolapselevel. Disc prolapse at L4-L5 and L5-S1 level constituted 85.5%.Magnetic resonance imaging findings of neural foramina compromise and nerve root compression were fairly correlated withclinical findings of radicular pain and neurological deficit. Clinical features and Magnetic resonance imaging findings of lumbar discprolasehad faircorrelation, but all imaging abnormalities do not have a clinical significance.

Comparison of computed tomography and magnetic resonance imaging for the evaluation of canine intranasal neoplasia.

PubMed

Drees, R; Forrest, L J; Chappell, R

2009-07-01

Canine intranasal neoplasia is commonly evaluated using computed tomography to indicate the diagnosis, to determine disease extent, to guide histological sampling location and to plan treatment. With the expanding use of magnetic resonance imaging in veterinary medicine, this modality has been recently applied for the same purpose. The aim of this study was to compare the features of canine intranasal neoplasia using computed tomography and magnetic resonance imaging. Twenty-one dogs with confirmed intranasal neoplasia underwent both computed tomography and magnetic resonance imaging. The images were reviewed retrospectively for the bony and soft tissue features of intranasal neoplasia. Overall computed tomography and magnetic resonance imaging performed very similarly. However, lysis of bones bordering the nasal cavity and mucosal thickening was found on computed tomography images more often than on magnetic resonance images. Small amounts of fluid in the nasal cavity were more often seen on magnetic resonance images. However, fluid in the frontal sinuses was seen equally well with both modalities. We conclude that computed tomography is satisfactory for evaluation of canine intranasal neoplasia, and no clinically relevant benefit is gained using magnetic resonance imaging for intranasal neoplasia without extent into the cranial cavity.

Osteoid osteoma of the scaphoid: magnetic resonance imaging vessel sign.

PubMed

Kussman, Steven R; Thompson, Michael; Chang, Eric Y

2015-01-01

Osteoid osteomas can be a challenging diagnosis, especially in smaller bones and, particularly, in the carpus. Clinical and imaging diagnosis may both be delayed due to other, more common, post-traumatic or inflammatory pathology in the same area. We present a case of a pathologically proven scaphoid osteoid osteoma with a feeding vessel sign on magnetic resonance imaging, previously described in long bones with computed tomography, as a helpful sign for accurate diagnosis in the scaphoid. Copyright © 2015 Elsevier Inc. All rights reserved.

Mathematical Development and Computational Analysis of Harmonic Phase-Magnetic Resonance Imaging (HARP-MRI) Based on Bloch Nuclear Magnetic Resonance (NMR) Diffusion Model for Myocardial Motion.

PubMed

Dada, Michael O; Jayeoba, Babatunde; Awojoyogbe, Bamidele O; Uno, Uno E; Awe, Oluseyi E

2017-09-13

Harmonic Phase-Magnetic Resonance Imaging (HARP-MRI) is a tagged image analysis method that can measure myocardial motion and strain in near real-time and is considered a potential candidate to make magnetic resonance tagging clinically viable. However, analytical expressions of radially tagged transverse magnetization in polar coordinates (which is required to appropriately describe the shape of the heart) have not been explored because the physics required to directly connect myocardial deformation of tagged Nuclear Magnetic Resonance (NMR) transverse magnetization in polar geometry and the appropriate harmonic phase parameters are not yet available. The analytical solution of Bloch NMR diffusion equation in spherical geometry with appropriate spherical wave tagging function is important for proper analysis and monitoring of heart systolic and diastolic deformation with relevant boundary conditions. In this study, we applied Harmonic Phase MRI method to compute the difference between tagged and untagged NMR transverse magnetization based on the Bloch NMR diffusion equation and obtained radial wave tagging function for analysis of myocardial motion. The analytical solution of the Bloch NMR equations and the computational simulation of myocardial motion as developed in this study are intended to significantly improve healthcare for accurate diagnosis, prognosis and treatment of cardiovascular related deceases at the lowest cost because MRI scan is still one of the most expensive anywhere. The analysis is fundamental and significant because all Magnetic Resonance Imaging techniques are based on the Bloch NMR flow equations.

Efficacy of magnetic resonance imaging for diagnosis of penile fracture: A controlled study

PubMed Central

Tarhan, Fatih; Hamarat, Mustafa B.; Can, Utku; Coskun, Alper; Camur, Emre; Sarica, Kemal

2017-01-01

Purpose To evaluate the diagnostic value of magnetic resonance imaging (MRI) in patients with suspected penile fracture. Materials and Methods A total of 122 patients admitted to our inpatient clinic with a suspicion of penile fracture following a recent history of penile trauma and who underwent surgical exploration were included this study. A thorough physical examination, a detailed medical history, description of the trauma, and preoperative International Index of Erectile Function (IIEF) scores were obtained for each patient prior to surgery. Thirty-eight of these patients were evaluated with MRI before the surgical exploration. Intraoperative findings were also recorded. Physical findings and IIEF scores were also recorded at postoperative 6 months. Results The mean age of our patient group was 36.5±12.3 years. Penile fracture was detected in 105 of 122 patients in whom surgical exploration was performed owing to a suspected diagnosis. The mean time interval from penile trauma to hospital admittance was 9.9±15.1 hours. No cavernosal defect was detected in 9 of 84 patients (10.7%) who were not evaluated with MRI prior to surgery. Compared with surgical exploration, MRI findings showed 100% (30 of 30) sensitivity and 87.5% (7 of 8) specificity in the diagnosis of penile fracture. MRI had a high negative predictive value of 100% (7 of 7) and a positive predictive value of 96.7% (30 of 31) with just 1 misdiagnosed patient. Conclusions MRI is a reliable diagnostic tool in the diagnosis of penile fractures. Compared to history and physical findings taken all together, the high sensitivity and specificity of this imaging technique can decrease the number of unnecessary surgical explorations. PMID:28681035

Efficacy of magnetic resonance imaging for diagnosis of penile fracture: A controlled study.

PubMed

Saglam, Erkin; Tarhan, Fatih; Hamarat, Mustafa B; Can, Utku; Coskun, Alper; Camur, Emre; Sarica, Kemal

2017-07-01

To evaluate the diagnostic value of magnetic resonance imaging (MRI) in patients with suspected penile fracture. A total of 122 patients admitted to our inpatient clinic with a suspicion of penile fracture following a recent history of penile trauma and who underwent surgical exploration were included this study. A thorough physical examination, a detailed medical history, description of the trauma, and preoperative International Index of Erectile Function (IIEF) scores were obtained for each patient prior to surgery. Thirty-eight of these patients were evaluated with MRI before the surgical exploration. Intraoperative findings were also recorded. Physical findings and IIEF scores were also recorded at postoperative 6 months. The mean age of our patient group was 36.5±12.3 years. Penile fracture was detected in 105 of 122 patients in whom surgical exploration was performed owing to a suspected diagnosis. The mean time interval from penile trauma to hospital admittance was 9.9±15.1 hours. No cavernosal defect was detected in 9 of 84 patients (10.7%) who were not evaluated with MRI prior to surgery. Compared with surgical exploration, MRI findings showed 100% (30 of 30) sensitivity and 87.5% (7 of 8) specificity in the diagnosis of penile fracture. MRI had a high negative predictive value of 100% (7 of 7) and a positive predictive value of 96.7% (30 of 31) with just 1 misdiagnosed patient. MRI is a reliable diagnostic tool in the diagnosis of penile fractures. Compared to history and physical findings taken all together, the high sensitivity and specificity of this imaging technique can decrease the number of unnecessary surgical explorations.

Differential diagnosis of left ventricular hypertrophy: usefulness of multimodality imaging and tissue characterization with cardiac magnetic resonance.

PubMed

Izgi, Cemil; Vassiliou, Vassilis; Baksi, A John; Prasad, Sanjay K

2016-11-01

Differential diagnosis of asymmetrical left ventricular hypertrophy may be challenging, particularly in patients with history of hypertension. A middle-aged man underwent an echocardiographic examination during workup for hypertension, which unexpectedly showed significant asymmetrical septal hypertrophy and raised suspicion for hypertrophic cardiomyopathy. Cardiovascular magnetic resonance confirmed the asymmetrical hypertrophy. No myocardial late gadolinium contrast enhancement was seen. However, precontrast T1 mapping revealed a low native myocardial T1 value. This was highly suggestive of Anderson-Fabry disease, which was subsequently proved with very low alpha galactosidase enzyme levels and mutation analysis. The case illustrates clinical usefulness of multimodality imaging and the novel tissue characterization techniques for assessment of left ventricular hypertrophy. © 2016, Wiley Periodicals, Inc.

Pitfalls and Limitations of Diffusion-Weighted Magnetic Resonance Imaging in the Diagnosis of Urinary Bladder Cancer

PubMed Central

Lin, Wei-Ching; Chen, Jeon-Hor

2015-01-01

Adequately selecting a therapeutic approach for bladder cancer depends on accurate grading and staging. Substantial inaccuracy of clinical staging with bimanual examination, cystoscopy, and transurethral resection of bladder tumor has facilitated the increasing utility of magnetic resonance imaging to evaluate bladder cancer. Diffusion-weighted imaging (DWI) is a noninvasive functional magnetic resonance imaging technique. The high tissue contrast between cancers and surrounding tissues on DWI is derived from the difference of water molecules motion. DWI is potentially a useful tool for the detection, characterization, and staging of bladder cancers; it can also monitor posttreatment response and provide information on predicting tumor biophysical behaviors. Despite advancements in DWI techniques and the use of quantitative analysis to evaluate the apparent diffusion coefficient values, there are some inherent limitations in DWI interpretation related to relatively poor spatial resolution, lack of cancer specificity, and lack of standardized image acquisition protocols and data analysis procedures that restrict the application of DWI and reproducibility of apparent diffusion coefficient values. In addition, inadequate bladder distension, artifacts, thinness of bladder wall, cancerous mimickers of normal bladder wall and benign lesions, and variations in the manifestation of bladder cancer may interfere with diagnosis and monitoring of treatment. Recognition of these pitfalls and limitations can minimize their impact on image interpretation, and carefully applying the analyzed results and combining with pathologic grading and staging to clinical practice can contribute to the selection of an adequate treatment method to improve patient care. PMID:26055180

Magnetic resonance T1 gradient-echo imaging in hepatolithiasis.

PubMed

Safar, F; Kamura, T; Okamuto, K; Sasai, K; Gejyo, F

2005-01-01

We examined the role of magnetic resonance T1-weighted gradient-echo (MRT1-GE) imaging in hepatolithiasis. MRT1-GE, precontrast computed tomography (CT), and magnetic resonance cholangiopancreatography (MRCP) of 10 patients with hepatolithiasis were compared for their diagnostic accuracies in the detection and localization of intrahepatic calculi. The diagnosis of hepatolithiasis was confirmed by surgery. For localization of the stone, we divided the bile ducts into six areas: right and left hepatic ducts and bile ducts of the lateral, medial, right anterior, and right posterior segments of the liver. Chemical analysis of the stones was performed in eight patients. The total number of segments proved by surgery to contain stones was 18. Although not significantly different, the sensitivity of MRT1-GE was 77.8% (14 of 18 segments), higher than that of MRCP (66.7%, 12 of 18 segments) and that of CT (50%, nine of 18 segments). The sensitivity of magnetic resonance imaging (MRCP + MRT1) was significantly higher than that of CT (p < 0.01). Multiple logistic regression analysis showed that the result of surgery was significantly affected only by the result of magnetic resonance imaging. On MRT1-GE, all the depicted stones appeared as high-intensity signal areas within the low-intensity bile duct irrespective of their chemical composition. MRT1-GE imaging provides complementary information concerning hepatolithiasis.

[The Application of Magnetic Resonance Imaging in Alzheimer's Disease].

PubMed

Matsuda, Hiroshi

2017-07-01

In Alzheimer's disease (AD), magnetic resonance imaging (MRI) is essential for early diagnosis, differential diagnosis, and evaluation of disease progression. In structural MRI, the automatic diagnosis of atrophy by computers, even when it is not visually noticeable, is possible in daily clinical practice. Furthermore, subfield volumetric measurements of the medial temporal structures, as well as longitudinal volume measurements with high accuracy, have been developed and are useful for calculating the needed sample size in clinical trials. In addition to detecting local atrophy, graph theory has been applied to structural MRI for evaluation of alterations of the brain networks potentially affected in AD.

Brain Magnetic Resonance Imaging as First-Line Investigation for Growth Hormone Deficiency Diagnosis in Early Childhood.

PubMed

Pampanini, Valentina; Pedicelli, Stefania; Gubinelli, Jessica; Scirè, Giuseppe; Cappa, Marco; Boscherini, Brunetto; Cianfarani, Stefano

2015-01-01

The diagnosis of growth hormone (GH) deficiency (GHD) in infancy and early childhood is not straightforward. GH stimulation tests are unsafe and unreliable in infants, and normative data are lacking. This study aims to investigate whether brain magnetic resonance imaging (MRI) may replace GH stimulation tests in the diagnosis of GHD in children younger than 4 years. We examined a retrospective cohort, with longitudinal follow-up, of 68 children consecutively diagnosed with GHD before the age of 4 years. The prevalence of hypothalamic-pituitary (HP) alterations at MRI and the associations with age and either isolated GHD (IGHD) or multiple pituitary hormone deficiency (MPHD) were assessed. The prevalences of IGHD and MPHD were 54.4 and 45.6%, respectively. In the first group, brain MRI showed abnormalities in 83.8%: isolated pituitary hypoplasia in 48.7% and complex defects in 35.1%. In patients with MPHD, MRI showed complex alterations in 100%. All children younger than 24 months showed HP MRI abnormalities, regardless of the diagnosis. Complex defects were found in 94% of patients younger than 12 months and in 75% of patients between 13 and 24 months. Our data suggest that brain MRI may represent the first-line investigation for diagnosing GHD in infancy and early childhood. © 2015 S. Karger AG, Basel.

Computerized tomography versus magnetic resonance imaging: a comparative study in hypothalamic-pituitary and parasellar pathology.

PubMed

Webb, S M; Ruscalleda, J; Schwarzstein, D; Calaf-Alsina, J; Rovira, A; Matos, G; Puig-Domingo, M; de Leiva, A

1992-05-01

We wished to analyse the relative value of computerized tomography and magnetic resonance in patients referred for evaluation of pituitary and parasellar lesions. We performed a separate evaluation by two independent neuroradiologists of computerized tomography and magnetic resonance images ordered numerically and anonymously, with no clinical data available. We studied 40 patients submitted for hypothalamic-pituitary study; 31 were carried out preoperatively, of which histological confirmation later became available in 14. The remaining nine patients were evaluated postoperatively. Over 40 parameters relating to the bony margins, cavernous sinuses, carotid arteries, optic chiasm, suprasellar cisterns, pituitary, pituitary stalk and extension of the lesion were evaluated. These reports were compared with the initial ones offered when the scans were ordered, and with the final diagnosis. Concordance between initial computerized tomography and magnetic resonance was observed in 27 cases (67.5%); among the discordant cases computerized tomography showed the lesion in two, magnetic resonance in 10, while in the remaining case reported to harbour a microadenoma on computerized tomography the differential diagnosis between a true TSH-secreting microadenoma and pituitary resistance to thyroid hormones is still unclear. Both neuroradiologists coincided in their reports in 32 patients (80%); when the initial report was compared with those of the neuroradiologists, concordance was observed with at least one of them in 34 instances (85%). Discordant results were observed principally in microadenomas secreting ACTH or PRL and in delayed puberty. In the eight patients with Cushing's disease (histologically confirmed in six) magnetic resonance was positive in five and computerized tomography in two; the abnormal image correctly identified the side of the lesion at surgery. In patients referred for evaluation of Cushing's syndrome or hyperprolactinaemia (due to microadenomas) or

Brain lymphoma: usefulness of the magnetic resonance spectroscopy.

PubMed

Taillibert, Sophie; Guillevin, Rémy; Menuel, Carole; Sanson, Marc; Hoang-Xuan, Khê; Chiras, Jacques; Duffau, Hugues

2008-01-01

The diagnosis of primary central nervous system lymphoma (PCNSL) should always be considered as an emergency because of the therapeutic consequences it implies. In immunocompetent patients, it relies on stereotactic biopsy. Unfortunately, clinical and radiological features may be misleading and delay the diagnostic procedure. The case we report here illustrates the contribution of magnetic resonance spectroscopy in the diagnostic approach of a very atypical PCNSL.

Usefulness of Magnetic Resonance Imaging for the Diagnosis of Hemochromatosis with Severe Hepatic Steatosis in Nonalcoholic Fatty Liver Disease.

PubMed

Nozaki, Yuichi; Sato, Noriko; Tajima, Tsuyoshi; Hasuo, Kanehiro; Kojima, Yasushi; Umemoto, Kumiko; Mishima, Saori; Mikami, Shintaro; Nakayama, Tomohiro; Igari, Toru; Akiyama, Junichi; Imamura, Masatoshi; Masaki, Naohiko; Yanase, Mikio

2016-01-01

The ratio of the number of patients with non-alcoholic steatohepatitis (NASH) to the total number of patients with liver dysfunction has increased in many countries around the world. Liver dysfunction is also caused by multiple blood transfusions in patients with leukemia and other hematological diseases, with liver dysfunction often accompanied by secondary hemochromatosis. This study describes a 25-year-old man with secondary hemochromatosis combined with NASH. Magnetic resonance imaging was useful for visualizing the distributions of both iron and fat in the liver of this patient in order to make a differential diagnosis and to evaluate the effect of treatment.

Another look at ultrasound and magnetic resonance imaging for diagnosis of placenta accreta.

PubMed

Budorick, Nancy E; Figueroa, Reinaldo; Vizcarra, Michael; Shin, James

2017-10-01

To compare the ability of magnetic resonance imaging (MRI) and ultrasound (US) in the diagnosis of placenta accreta, to examine the success of various sonographic and MRI features to correctly predict invasive placenta, and to define a specific role for MRI in placenta accreta. After Institutional Review Board approval, a blinded retrospective review was undertaken of US and MRI findings from 45 patients who had an obstetrical US and placental MRI between August 2006 and January 2012. Correlation with clinical history and pathologic findings was performed. US and MRI had similar sensitivity, specificity and positive and negative predictive values for placenta accreta. The best predictors of invasion by US were loss of the myometrial mantle, increased intraplacental vascularity and loss of the bladder wall echogenicity. The best predictors of invasion by MRI were loss of retroplacental myometrial mantle, a heterogeneous placenta, and intraplacental hemorrhage. Body mass index (BMI) did not affect the ability to make a diagnosis by either US or MRI. MRI proved effective in better evaluation of a posterior placenta with suspicion of placenta accreta. There was modality disagreement in 11 of 45 cases and MRI was correct in 9 of these 11 cases, all true negative (TN) cases. MRI should be considered in any case with posterior placenta previa and suspicion of accreta, in any case with clinical suspicion for accreta and discordant US findings, and in any case in which percreta is suspected.

Accuracy of ultrasonography and magnetic resonance imaging in the diagnosis of placenta accreta.

PubMed

Riteau, Anne-Sophie; Tassin, Mikael; Chambon, Guillemette; Le Vaillant, Claudine; de Laveaucoupet, Jocelyne; Quéré, Marie-Pierre; Joubert, Madeleine; Prevot, Sophie; Philippe, Henri-Jean; Benachi, Alexandra

2014-01-01

To evaluate the accuracy of ultrasonography and magnetic resonance imaging (MRI) in the diagnosis of placenta accreta and to define the most relevant specific ultrasound and MRI features that may predict placental invasion. This study was approved by the institutional review board of the French College of Obstetricians and Gynecologists. We retrospectively reviewed the medical records of all patients referred for suspected placenta accreta to two university hospitals from 01/2001 to 05/2012. Our study population included 42 pregnant women who had been investigated by both ultrasonography and MRI. Ultrasound images and MRI were blindly reassessed for each case by 2 raters in order to score features that predict abnormal placental invasion. Sensitivity in the diagnosis of placenta accreta was 100% with ultrasound and 76.9% for MRI (P = 0.03). Specificity was 37.5% with ultrasonography and 50% for MRI (P = 0.6). The features of greatest sensitivity on ultrasonography were intraplacental lacunae and loss of the normal retroplacental clear space. Increased vascularization in the uterine serosa-bladder wall interface and vascularization perpendicular to the uterine wall had the best positive predictive value (92%). At MRI, uterine bulging had the best positive predictive value (85%) and its combination with the presence of dark intraplacental bands on T2-weighted images improved the predictive value to 90%. Ultrasound imaging is the mainstay of screening for placenta accreta. MRI appears to be complementary to ultrasonography, especially when there are few ultrasound signs.

Application of magnetic resonance imaging in diagnosis of Uterus Cervical Carcinoma.

PubMed

Peng, Jidong; Wang, Weiqiang; Zeng, Daohui

2017-01-01

Effective treatment of Uterus Cervical Carcinoma (UCC) rely heavily on the precise pre-surgical staging. The conventional International Federation of Gynecology and Obstetrics (FIGO) system based on clinical examination is being applied worldwide for UCC staging. Yet its performance just appears passable. Thus, this study aims to investigate the value of applying Magnetic Resonance Imaging (MRI) with clinical examination in staging of UCC. A retrospective dataset involving 164 patients diagnosed with UCC was enrolled in this study. The mean age of this study population was 46.1 years (range, 28-#x2013;75 years). All patients underwent operations and UCC types were confirmed by pathological examinations. The tumor stages were determined by two experienced Gynecologist independently based on FIGO examinations and MRI. The diagnostic results were also compared with the post-operative pathologic reports. Statistical data analysis on diagnostic performance was then done and reported. The study results showed that the overall accuracy of applying MRI in UCC staging was 82.32%, while using FIGO staging method, the staging accuracy was 59.15%. MRI is suitable to evaluate tumor extent with high accuracy, and it can offer more objective information for the diagnosis and staging of UCC. Compared with clinical examinations based on FIGO, MRI illustrated relatively high accuracy in evaluating UCC staging, and is worthwhile to be recommended in future clinical practice.

Cardiac magnetic resonance imaging for the diagnosis of coronary artery disease: an evidence-based analysis.

PubMed

2010-01-01

In July 2009, the Medical Advisory Secretariat (MAS) began work on Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease (CAD), an evidence-based review of the literature surrounding different cardiac imaging modalities to ensure that appropriate technologies are accessed by patients suspected of having CAD. This project came about when the Health Services Branch at the Ministry of Health and Long-Term Care asked MAS to provide an evidentiary platform on effectiveness and cost-effectiveness of non-invasive cardiac imaging modalities.After an initial review of the strategy and consultation with experts, MAS identified five key non-invasive cardiac imaging technologies for the diagnosis of CAD. Evidence-based analyses have been prepared for each of these five imaging modalities: cardiac magnetic resonance imaging, single photon emission computed tomography, 64-slice computed tomographic angiography, stress echocardiography, and stress echocardiography with contrast. For each technology, an economic analysis was also completed (where appropriate). A summary decision analytic model was then developed to encapsulate the data from each of these reports (available on the OHTAC and MAS website).The Non-Invasive Cardiac Imaging Technologies for the Diagnosis of Coronary Artery Disease series is made up of the following reports, which can be publicly accessed at the MAS website at: www.health.gov.on.ca/mas or at www.health.gov.on.ca/english/providers/program/mas/mas_about.htmlSINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE: An Evidence-Based AnalysisSTRESS ECHOCARDIOGRAPHY FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE: An Evidence-Based AnalysisSTRESS ECHOCARDIOGRAPHY WITH CONTRAST FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE: An Evidence-Based Analysis64-Slice Computed Tomographic Angiography for the Diagnosis of Coronary Artery Disease: An Evidence-Based AnalysisCARDIAC MAGNETIC RESONANCE IMAGING FOR

Comparison of computed tomography and magnetic resonance imaging for the evaluation of canine intranasal neoplasia

PubMed Central

Drees, R.; Forrest, L. J.; Chappell, R.

2009-01-01

Objectives Canine intranasal neoplasia is commonly evaluated using computed tomography to indicate the diagnosis, to determine disease extent, to guide histological sampling location and to plan treatment. With the expanding use of magnetic resonance imaging in veterinary medicine, this modality has been recently applied for the same purpose. The aim of this study was to compare the features of canine intranasal neoplasia using computed tomography and magnetic resonance imaging. Methods Twenty-one dogs with confirmed intranasal neoplasia underwent both computed tomography and magnetic resonance imaging. The images were reviewed retrospectively for the bony and soft tissue features of intranasal neoplasia. Results Overall computed tomography and magnetic resonance imaging performed very similarly. However, lysis of bones bordering the nasal cavity and mucosal thickening was found on computed tomography images more often than on magnetic resonance images. Small amounts of fluid in the nasal cavity were more often seen on magnetic resonance images. However, fluid in the frontal sinuses was seen equally well with both modalities. Clinical Significance We conclude that computed tomography is satisfactory for evaluation of canine intranasal neoplasia, and no clinically relevant benefit is gained using magnetic resonance imaging for intranasal neoplasia without extent into the cranial cavity. PMID:19508490

Cardiac magnetic resonance in hypertrophic cardiomyopathy: current state of the art.

PubMed

Kwon, Deborah H; Desai, Milind Y

2010-01-01

Hypertrophic cardiomyopathy is a complex disorder with significant heterogeneity in clinical characteristics and natural history. Traditionally, the diagnosis has been based on clinical assessment and echocardiography; however, persistent challenges in its noninvasive evaluation remain. Hence, improved diagnostic techniques could lead to better risk stratification of patients, which would potentially identify patients likely to benefit from effective therapies. Recent studies have demonstrated the increasing utility of cardiac magnetic resonance in the management of this disease. With the increasing utilization of genetics, cardiac magnetic resonance is likely to play an even more important role in discerning the subtle morphologic differences seen in such patients with similar genotypic profiles.

Magnetic Resonance Imaging Evaluation of Cardiac Masses

PubMed Central

Braggion-Santos, Maria Fernanda; Koenigkam-Santos, Marcel; Teixeira, Sara Reis; Volpe, Gustavo Jardim; Trad, Henrique Simão; Schmidt, André

2013-01-01

Background Cardiac tumors are extremely rare; however, when there is clinical suspicion, proper diagnostic evaluation is necessary to plan the most appropriate treatment. In this context, cardiovascular magnetic resonance imaging (CMRI) plays an important role, allowing a comprehensive characterization of such lesions. Objective To review cases referred to a CMRI Department for investigation of cardiac and paracardiac masses. To describe the positive case series with a brief review of the literature for each type of lesion and the role of cardiovascular magnetic resonance imaging in evaluation. Methods Between August 2008 and December 2011, all cases referred for CMRI with suspicion of tumor involving the heart were reviewed. Cases with positive histopathological diagnosis, clinical evolution or therapeutic response compatible with the clinical suspicion and imaging findings were selected. Results Among the 13 cases included in our study, eight (62%) had histopathological confirmation. We describe five benign tumors (myxomas, rhabdomyoma and fibromas), five malignancies (sarcoma, lymphoma, Richter syndrome involving the heart and metastatic disease) and three non-neoplastic lesions (pericardial cyst, intracardiac thrombus and infectious vegetation). Conclusion CMRI plays an important role in the evaluation of cardiac masses of non-neoplastic and neoplastic origin, contributing to a more accurate diagnosis in a noninvasive manner and assisting in treatment planning, allowing safe clinical follow-up with good reproducibility. PMID:23887734

Comparison of magnetic resonance imaging and computed tomography in suspected lesions in the posterior cranial fossa.

PubMed Central

Teasdale, G. M.; Hadley, D. M.; Lawrence, A.; Bone, I.; Burton, H.; Grant, R.; Condon, B.; Macpherson, P.; Rowan, J.

1989-01-01

OBJECTIVE--To compare computed tomography and magnetic resonance imaging in investigating patients suspected of having a lesion in the posterior cranial fossa. DESIGN--Randomised allocation of newly referred patients to undergo either computed tomography or magnetic resonance imaging; the alternative investigation was performed subsequently only in response to a request from the referring doctor. SETTING--A regional neuroscience centre serving 2.7 million. PATIENTS--1020 Patients recruited between April 1986 and December 1987, all suspected by neurologists, neurosurgeons, or other specialists of having a lesion in the posterior fossa and referred for neuroradiology. The groups allocated to undergo computed tomography or magnetic resonance imaging were well matched in distributions of age, sex, specialty of referring doctor, investigation as an inpatient or an outpatient, suspected site of lesion, and presumed disease process; the referring doctor's confidence in the initial clinical diagnosis was also similar. INTERVENTIONS--After the patients had been imaged by either computed tomography or magnetic resonance (using a resistive magnet of 0.15 T) doctors were given the radiologist's report and a form asking if they considered that imaging with the alternative technique was necessary and, if so, why; it also asked for their current diagnoses and their confidence in them. MAIN OUTCOME MEASURES--Number of requests for the alternative method of investigation. Assessment of characteristics of patients for whom further imaging was requested and lesions that were suspected initially and how the results of the second imaging affected clinicians' and radiologists' opinions. RESULTS--Ninety three of the 501 patients who initially underwent computed tomography were referred subsequently for magnetic resonance imaging whereas only 28 of the 493 patients who initially underwent magnetic resonance imaging were referred subsequently for computed tomography. Over the study the

[Gastric magnetic resonance study (methods, semiotics)].

PubMed

Stashuk, G A

2003-01-01

The paper shows the potentialities of gastric study by magnetic resonance imaging (MRI). The methodic aspects of gastric study have been worked out. The MRI-semiotics of the unchanged and tumor-affected wall of the stomach and techniques in examining patients with gastric cancer of various sites are described. Using the developed procedure, MRI was performed in 199 patients, including 154 patients with gastric pathology and 45 control individuals who had no altered gastric wall. Great emphasis is placed on the role of MRI in the diagnosis of endophytic (diffuse) gastric cancer that is of priority value in its morphological structure. MRI was found to play a role in the diagnosis of the spread of a tumorous process both along the walls of the stomach and to its adjacent anatomic structures.

Comparison of radiography and magnetic resonance imaging for evaluating the extent of nasal neoplasia in dogs.

PubMed

Petite, A F B; Dennis, R

2006-09-01

Magnetic resonance imaging (MRI) is increasingly used in veterinary practice and, in some centres, is part of the diagnostic work-up of small animals with nasal disease. However, there are no published studies which critically evaluate the use of magnetic resonance imaging for this purpose. The purpose of this work was to assess the changes seen using magnetic resonance imaging and to compare them with radiography. The study included 12 dogs that had undergone both radiography and magnetic resonance imaging of the nasal cavity and had a histopathological diagnosis of malignant nasal neoplasia. Two pairs of board-certified radiologists scored the radiographs and the MRI scans, evaluating 10 signs of abnormality using a simple scoring system. Magnetic resonance imaging features were described in detail, and radiographic and magnetic resonance imaging scores for each sign as well as total scores were compared. Magnetic resonance imaging often showed that the tumour was more extensive than it had appeared on radiography but occasionally showed that radiographs had overestimated its size. Although radiography was reliable for assessment of the presence and size of a mass and for the extent of turbinate destruction, it usually failed to show occlusion of the major airway passages that were evident on magnetic resonance imaging. Extension of the tumour into the opposite nasal cavity, frontal sinus, orbit and cranial cavity was shown much better on magnetic resonance imaging. Minor but significant extension beyond the nasal cavity, which is important for treatment planning and prognosis, requires magnetic resonance imaging for demonstration, although radiography shows major changes reliably.

[Surface coils for magnetic-resonance images].

PubMed

Rodríguez-González, Alfredo Odón; Amador-Baheza, Ricardo; Rojas-Jasso, Rafael; Barrios-Alvarez, Fernando Alejandro

2005-01-01

Since the introduction of magnetic resonance imaging in Mexico, the development of this important medical imaging technology has been almost non-existing in our country. The very first surface coil prototypes for clinical applications in magnetic resonance imaging has been developed at the Center of Research in Medical Imaging and Instrumentation of the Universidad Autónoma Metropolitana Iztapalapa (Metropolitan Autonomous University, Campus Iztapalapa). Two surface coil prototypes were built: a) a circular-shaped coil and b) a square-shaped coil for multiple regions of the body, such as heart, brain, knee, hands, and ankles. These coils were tested on the 1.5T imager of the ABC Hospital-Tacubaya, located in Mexico City. Brain images of healthy volunteers were obtained in different orientations: sagittal, coronal, and axial. Since images showed a good-enough clinical quality for diagnosis, it is fair to say that these coil prototypes can be used in the clinical environment, and with small modifications, they can be made compatible with almost any commercial scanner. This type of development can offer new alternatives for further collaboration between the research centers and the radiology community, in the search of new applications and developments of this imaging technique.

Accuracy of Ultrasonography and Magnetic Resonance Imaging in the Diagnosis of Placenta Accreta

PubMed Central

Riteau, Anne-Sophie; Tassin, Mikael; Chambon, Guillemette; Le Vaillant, Claudine; de Laveaucoupet, Jocelyne; Quéré, Marie-Pierre; Joubert, Madeleine; Prevot, Sophie; Philippe, Henri-Jean; Benachi, Alexandra

2014-01-01

Purpose To evaluate the accuracy of ultrasonography and magnetic resonance imaging (MRI) in the diagnosis of placenta accreta and to define the most relevant specific ultrasound and MRI features that may predict placental invasion. Material and Methods This study was approved by the institutional review board of the French College of Obstetricians and Gynecologists. We retrospectively reviewed the medical records of all patients referred for suspected placenta accreta to two university hospitals from 01/2001 to 05/2012. Our study population included 42 pregnant women who had been investigated by both ultrasonography and MRI. Ultrasound images and MRI were blindly reassessed for each case by 2 raters in order to score features that predict abnormal placental invasion. Results Sensitivity in the diagnosis of placenta accreta was 100% with ultrasound and 76.9% for MRI (P = 0.03). Specificity was 37.5% with ultrasonography and 50% for MRI (P = 0.6). The features of greatest sensitivity on ultrasonography were intraplacental lacunae and loss of the normal retroplacental clear space. Increased vascularization in the uterine serosa-bladder wall interface and vascularization perpendicular to the uterine wall had the best positive predictive value (92%). At MRI, uterine bulging had the best positive predictive value (85%) and its combination with the presence of dark intraplacental bands on T2-weighted images improved the predictive value to 90%. Conclusion Ultrasound imaging is the mainstay of screening for placenta accreta. MRI appears to be complementary to ultrasonography, especially when there are few ultrasound signs. PMID:24733409

Magnetic Resonance Imaging (MRI): Dynamic Pelvic Floor

MedlinePlus

... Site Index A-Z Magnetic Resonance Imaging (MRI) – Dynamic Pelvic Floor Dynamic pelvic floor magnetic resonance imaging ( ... the limitations of pelvic floor MRI? What is dynamic pelvic floor MRI? Magnetic resonance imaging (MRI) is ...

Nanoamplifiers synthesized from gadolinium and gold nanocomposites for magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Tian, Xiumei; Shao, Yuanzhi; He, Haoqiang; Liu, Huan; Shen, Yingying; Huang, Wenlin; Li, Li

2013-03-01

We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential.We have synthesized an efficient and highly sensitive nanoamplifier composed of gadolinium-doped silica nanoparticles and gold nanoparticles (AuNPs). Magnetic resonance imaging (MRI) in vitro and in vivo assays revealed enhancement of signal sensitivity, which may be explained by electron transfer between water and gadolinium-doped nanoparticles, apparent in the presence of gold. In vitro and in vivo evaluation demonstrated nanoamplifier incurred minimal cytotoxicity and immunotoxicity, increased stability, and gradual excretion patterns. Tumor targeted properties were preliminarily determined when the nanoamplifier was injected into mouse models of colon cancer liver metastasis. Furthermore, although AuNPs departed from the nanoamplifiers in specific mice tissues, optical and magnetic resonance imaging was efficient, especially in metastatic tumors. These assays validate our nanoamplifier as an effective MRI signal enhancer with sensitive cancer diagnosis potential. Electronic supplementary information

[New ASAS criteria for the diagnosis of spondyloarthritis: diagnosing sacroiliitis by magnetic resonance imaging].

PubMed

Banegas Illescas, M E; López Menéndez, C; Rozas Rodríguez, M L; Fernández Quintero, R M

2014-01-01

Radiographic sacroiliitis has been included in the diagnostic criteria for spondyloarthropathies since the Rome criteria were defined in 1961. However, in the last ten years, magnetic resonance imaging (MRI) has proven more sensitive in the evaluation of the sacroiliac joints in patients with suspected spondyloarthritis and symptoms of sacroiliitis; MRI has proven its usefulness not only for diagnosis of this disease, but also for the follow-up of the disease and response to treatment in these patients. In 2009, The Assessment of SpondyloArthritis international Society (ASAS) developed a new set of criteria for classifying and diagnosing patients with spondyloarthritis; one important development with respect to previous classifications is the inclusion of MRI positive for sacroiliitis as a major diagnostic criterion. This article focuses on the radiologic part of the new classification. We describe and illustrate the different alterations that can be seen on MRI in patients with sacroiliitis, pointing out the limitations of the technique and diagnostic pitfalls. Copyright © 2013 SERAM. Published by Elsevier Espana. All rights reserved.

Role of transvaginal sonography and magnetic resonance imaging in the diagnosis of uterine adenomyosis.

PubMed

Bazot, Marc; Daraï, Emile

2018-03-01

The aim of the present review, conducted according to PRISMA statement recommendations, was to evaluate the contribution of transvaginal sonography (TVS) and magnetic resonance imaging (MRI) to diagnose adenomyosis. Although there is a lack of consensus on adenomyosis classification, three subtypes are described, internal, external adenomyosis, and adenomyomas. Using TVS, whatever the subtype, pooled sensitivities, pooled specificities, and pooled positive likelihood ratios are 0.72-0.82, 0.85-0.81, and 4.67-3.7, respectively, but with a high heterogeneity between the studies. MRI has a pooled sensitivity of 0.77, specificity of 0.89, positive likelihood ratio of 6.5, and negative likelihood ratio of 0.2 for all subtypes. Our results suggest that MRI is more useful than TVS in the diagnosis of adenomyosis. Further studies are required to determine the performance of direct signs (cystic component) and indirect signs (characteristics of junctional zone) to avoid misdiagnosis of adenomyosis. Copyright © 2018 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Magnetic Resonance Imaging (MRI) Safety

MedlinePlus

... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how does ... What is MRI and how does it work? Magnetic resonance imaging, or MRI, is a way of obtaining detailed ...

Magnetic resonance imaging in the new paradigm for the diagnosis of prostate cancer.

PubMed

Vilanova, J C; Catalá, V

For various reasons, prostate cancer is a major public health problem. It is a very common cancer, but has a very low mortality rate because it comprises two types of disease: one insignificant, indolent, and much more common, and the other aggressive, significant, and much less common. The routine diagnostic approach to prostate cancer has been systematic blind biopsies, which has low detection rates and might detect low risk, insignificant prostate cancer, leading to overdiagnosis and overtreatment of indolent cancers. The possibility of including multiparametric magnetic resonance imaging in the diagnostic management to improve the detection of aggressive cancer while reducing the overdiagnosis of indolent cancer represents a change in the diagnostic management. This article updates knowledge about the diagnostic management of prostate cancer including multiparametric magnetic resonance imaging. Copyright © 2016 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Partially orthogonal resonators for magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Chacon-Caldera, Jorge; Malzacher, Matthias; Schad, Lothar R.

2017-02-01

Resonators for signal reception in magnetic resonance are traditionally planar to restrict coil material and avoid coil losses. Here, we present a novel concept to model resonators partially in a plane with maximum sensitivity to the magnetic resonance signal and partially in an orthogonal plane with reduced signal sensitivity. Thus, properties of individual elements in coil arrays can be modified to optimize physical planar space and increase the sensitivity of the overall array. A particular case of the concept is implemented to decrease H-field destructive interferences in planar concentric in-phase arrays. An increase in signal to noise ratio of approximately 20% was achieved with two resonators placed over approximately the same planar area compared to common approaches at a target depth of 10 cm at 3 Tesla. Improved parallel imaging performance of this configuration is also demonstrated. The concept can be further used to increase coil density.

Smart Contrast Agents for Magnetic Resonance Imaging.

PubMed

Bonnet, Célia S; Tóth, Éva

2016-01-01

By visualizing bioactive molecules or biological parameters in vivo, molecular imaging is searching for information at the molecular level in living organisms. In addition to contributing to earlier and more personalized diagnosis in medicine, it also helps understand and rationalize the molecular factors underlying physiological and pathological processes. In magnetic resonance imaging (MRI), complexes of paramagnetic metal ions, mostly lanthanides, are commonly used to enhance the intrinsic image contrast. They rely either on the relaxation effect of these metal chelates (T(1) agents), or on the phenomenon of paramagnetic chemical exchange saturation transfer (PARACEST agents). In both cases, responsive molecular magnetic resonance imaging probes can be designed to report on various biomarkers of biological interest. In this context, we review recent work in the literature and from our group on responsive T(1) and PARACEST MRI agents for the detection of biogenic metal ions (such as calcium or zinc), enzymatic activities, or neurotransmitter release. These examples illustrate the general strategies that can be applied to create molecular imaging agents with an MRI detectable response to biologically relevant parameters.

Tunable Magnetic Resonance in Microwave Spintronics Devices

NASA Technical Reports Server (NTRS)

Chen, Yunpeng; Fan, Xin; Xie, Yunsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

2015-01-01

Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe based tunable microwave spintronics devices, which is 10X higher than conventional methods.

Tunable Magnetic Resonance in Microwave Spintronics Devices

NASA Technical Reports Server (NTRS)

Chen, Yunpeng; Fan, Xin; Xie, Yungsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

2015-01-01

Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe-based tunable microwave spintronics devices, which is 10X higher than conventional methods.

Cardiovascular magnetic resonance in systemic hypertension

PubMed Central

2012-01-01

Systemic hypertension is a highly prevalent potentially modifiable cardiovascular risk factor. Imaging plays an important role in the diagnosis of underlying causes for hypertension, in assessing cardiovascular complications of hypertension, and in understanding the pathophysiology of the disease process. Cardiovascular magnetic resonance (CMR) provides accurate and reproducible measures of ventricular volumes, mass, function and haemodynamics as well as uniquely allowing tissue characterization of diffuse and focal fibrosis. In addition, CMR is well suited for exclusion of common secondary causes for hypertension. We review the current and emerging clinical and research applications of CMR in hypertension. PMID:22559053

Magnetic Resonance Angiography in the Diagnosis of Cerebral Arteriovenous Malformation and Dural Arteriovenous Fistulas: Comparison of Time-Resolved Magnetic Resonance Angiography and Three Dimensional Time-of-Flight Magnetic Resonance Angiography

PubMed Central

Cheng, Yu-Ching; Chen, Hung-Chieh; Wu, Chen-Hao; Wu, Yi-Ying; Sun, Ming-His; Chen, Wen-Hsien; Chai, Jyh-Wen; Chi-Chang Chen, Clayton

2016-01-01

Background Traditional digital subtraction angiography (DSA) is currently the gold standard diagnostic method for the diagnosis and evaluation of cerebral arteriovenous malformation (AVM) and dural arteriovenous fistulas (dAVF). Objectives The aim of this study was to analyze different less invasive magnetic resonance angiography (MRA) images, time-resolved MRA (TR-MRA) and three-dimensional time-of-flight MRA (3D TOF MRA) to identify their diagnostic accuracy and to determine which approach is most similar to DSA. Patients and Methods A total of 41 patients with AVM and dAVF at their initial evaluation or follow-up after treatment were recruited in this study. We applied time-resolved angiography using keyhole (4D-TRAK) MRA to perform TR-MRA and 3D TOF MRA examinations simultaneously followed by DSA, which was considered as a standard reference. Two experienced neuroradiologists reviewed the images to compare the diagnostic accuracy, arterial feeder and venous drainage between these two MRA images. Inter-observer agreement for different MRA images was assessed by Kappa coefficient and the differences of diagnostic accuracy between MRA images were evaluated by the Wilcoxon rank sum test. Results Almost all vascular lesions (92.68%) were correctly diagnosed using 4D-TRAK MRA. However, 3D TOF MRA only diagnosed 26 patients (63.41%) accurately. There were statistically significant differences regarding lesion diagnostic accuracy (P = 0.008) and venous drainage identification (P < 0.0001) between 4D-TRAK MRA and 3D TOF MRA. The results indicate that 4D-TRAK MRA is superior to 3D TOF MRA in the assessment of lesions. Conclusion Compared with 3D TOF MRA, 4D-TRAK MRA proved to be a more reliable screening modality and follow-up method for the diagnosis of cerebral AVM and dAVF. PMID:27679690

Diagnosis and quantification of fibrosis, steatosis, and hepatic siderosis through multiparametric magnetic resonance imaging.

PubMed

Stoopen-Rometti, M; Encinas-Escobar, E R; Ramirez-Carmona, C R; Wolpert-Barraza, E; Kimura-Hayama, E; Sosa-Lozano, L A; Favila, R; Kimura-Fujikami, Y; Saavedra-Abril, J A; Loaeza-Del Castillo, A

The presence of liver fibrosis is the common denominator in numerous chronic liver diseases that can progress to fibrosis and hepatocellular carcinoma. Most important, with respect to frequency, are viral hepatitis and non-alcoholic fatty liver disease, the prevalence of which is increasing in epidemic proportions. Liver biopsy, albeit imperfect, continues to be the criterion standard, but in many clinical situations tends to be replaced with noninvasive imaging methods. The aim of the present article was to describe our imaging department experience with magnetic resonance elastography and to analyze and discuss recently published results in gastroenterology, hepatology, and radiology from other authors in the literature, complemented with a PubMed search covering the last 10 years. Magnetic resonance elastography is an efficacious, noninvasive method with results that are concordant with liver biopsy. It is superior to ultrasound elastography because it evaluates a much greater volume of hepatic tissue and shows the often heterogeneous lesion distribution. The greatest advantage of the magnetic resonance protocol described is the fact that it quantifies fibrosis, fat content, and iron content in the same 25min examination specifically directed for that purpose, resulting in a favorable cost-benefit ratio for the patient and/or institution. Copyright © 2016 Asociación Mexicana de Gastroenterología. Publicado por Masson Doyma México S.A. All rights reserved.

Magnetic resonance imaging of placenta accreta

PubMed Central

Varghese, Binoj; Singh, Navdeep; George, Regi A.N; Gilvaz, Sareena

2013-01-01

Placenta accreta (PA) is a severe pregnancy complication which occurs when the chorionic villi (CV) invade the myometrium abnormally. Optimal management requires accurate prenatal diagnosis. Ultrasonography (USG) and magnetic resonance imaging (MRI) are the modalities for prenatal diagnosis of PA, although USG remains the primary investigation of choice. MRI is a complementary technique and reserved for further characterization when USG is inconclusive or incomplete. Breath-hold T2-weighted half-Fourier rapid acquisition with relaxation enhancement (RARE) and balanced steady-state free precession imaging in the three orthogonal planes is the key MRI technique. Markedly heterogeneous placenta, thick intraplacental dark bands on half-Fourier acquisition single-shot turbo spin-echo (HASTE), and disorganized abnormal intraplacental vascularity are the cardinal MRI features of PA. MRI is less reliable in differentiating between different degrees of placental invasion, especially between accreta vera and increta. PMID:24604945

What does magnetic resonance imaging add to the prenatal ultrasound diagnosis of facial clefts?

PubMed

Mailáth-Pokorny, M; Worda, C; Krampl-Bettelheim, E; Watzinger, F; Brugger, P C; Prayer, D

2010-10-01

Ultrasound is the modality of choice for prenatal detection of cleft lip and palate. Because its accuracy in detecting facial clefts, especially isolated clefts of the secondary palate, can be limited, magnetic resonance imaging (MRI) is used as an additional method for assessing the fetus. The aim of this study was to investigate the role of fetal MRI in the prenatal diagnosis of facial clefts. Thirty-four pregnant women with a mean gestational age of 26 (range, 19-34) weeks underwent in utero MRI, after ultrasound examination had identified either a facial cleft (n = 29) or another suspected malformation (micrognathia (n = 1), cardiac defect (n = 1), brain anomaly (n = 2) or diaphragmatic hernia (n = 1)). The facial cleft was classified postnatally and the diagnoses were compared with the previous ultrasound findings. There were 11 (32.4%) cases with cleft of the primary palate alone, 20 (58.8%) clefts of the primary and secondary palate and three (8.8%) isolated clefts of the secondary palate. In all cases the primary and secondary palate were visualized successfully with MRI. Ultrasound imaging could not detect five (14.7%) facial clefts and misclassified 15 (44.1%) facial clefts. The MRI classification correlated with the postnatal/postmortem diagnosis. In our hands MRI allows detailed prenatal evaluation of the primary and secondary palate. By demonstrating involvement of the palate, MRI provides better detection and classification of facial clefts than does ultrasound alone. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.

Development and validation of a questionnaire evaluating patient anxiety during Magnetic Resonance Imaging: the Magnetic Resonance Imaging-Anxiety Questionnaire (MRI-AQ).

PubMed

Ahlander, Britt-Marie; Årestedt, Kristofer; Engvall, Jan; Maret, Eva; Ericsson, Elisabeth

2016-06-01

To develop and validate a new instrument measuring patient anxiety during Magnetic Resonance Imaging examinations, Magnetic Resonance Imaging- Anxiety Questionnaire. Questionnaires measuring patients' anxiety during Magnetic Resonance Imaging examinations have been the same as used in a wide range of conditions. To learn about patients' experience during examination and to evaluate interventions, a specific questionnaire measuring patient anxiety during Magnetic Resonance Imaging is needed. Psychometric cross-sectional study with test-retest design. A new questionnaire, Magnetic Resonance Imaging-Anxiety Questionnaire, was designed from patient expressions of anxiety in Magnetic Resonance Imaging-scanners. The sample was recruited between October 2012-October 2014. Factor structure was evaluated with exploratory factor analysis and internal consistency with Cronbach's alpha. Criterion-related validity, known-group validity and test-retest was calculated. Patients referred for Magnetic Resonance Imaging of either the spine or the heart, were invited to participate. The development and validation of Magnetic Resonance Imaging-Anxiety Questionnaire resulted in 15 items consisting of two factors. Cronbach's alpha was found to be high. Magnetic Resonance Imaging-Anxiety Questionnaire correlated higher with instruments measuring anxiety than with depression scales. Known-group validity demonstrated a higher level of anxiety for patients undergoing Magnetic Resonance Imaging scan of the heart than for those examining the spine. Test-retest reliability demonstrated acceptable level for the scale. Magnetic Resonance Imaging-Anxiety Questionnaire bridges a gap among existing questionnaires, making it a simple and useful tool for measuring patient anxiety during Magnetic Resonance Imaging examinations. © 2016 The Authors. Journal of Advanced Nursing Published by John Wiley & Sons Ltd.

Magnetic field detection using magnetorheological optical resonators

NASA Astrophysics Data System (ADS)

Rubino, Edoardo; Ioppolo, Tindaro

2018-02-01

In this paper, we investigate the feasibility of a magnetic field sensor that is based on a magnetorheological micro-optical resonator. The optical resonator has a spherical shape and a diameter of a few hundred micrometers. The resonator is fabricated by using a polymeric matrix made of polyvinyl chloride (PVC) plastisol with embedded magnetically polarizable micro-particles. When the optical resonator is subjected to an external magnetic field, the morphology (radius and refractive index) of the resonator is perturbed by the magnetic forces acting on it, leading to a shift of the optical resonances also known as whispering gallery modes (WGM). In this study, the effect of a static and harmonic magnetic field, as well as the concentration of the magnetic micro-particles on the optical mode shift is investigated. The optical resonances obtained with the PVC plastisol resonator showed a quality factor of 106 . The dynamical behavior of the optical resonator is investigated in the range between 0 and 200 Hz. The sensitivity of the optical resonator reaches a maximum value for a ratio between micro-particles and the polymeric matrix of 2:1 in weight. Experimental results indicate a sensitivity of 0.297 pm/mT leading to a resolution of 336 μT.

Magnetic resonance for laryngeal cancer.

PubMed

Maroldi, Roberto; Ravanelli, Marco; Farina, Davide

2014-04-01

This review summarizes the most recent experiences on the integration of magnetic resonance in assessing the local extent of laryngeal cancer and detecting submucosal recurrences. Advances in magnetic resonance have been characterized by the development of technical solutions that shorten the acquisition time, thereby reducing motion artifacts, and increase the spatial resolution. Phased-array surface coils, directly applied to the neck, enable the use of parallel-imaging techniques, which greatly reduce the acquisition time, and amplify the signal intensity, being closer to the larynx. One of the most important drawbacks of this technique is the small field-of-view, restricting the imaged area to the larynx. Furthermore, diffusion-weighted imaging (DWI) has increased the set of magnetic resonance sequences. Differently from computed tomography (CT), which has only two variables (precontrast/postcontrast), magnetic resonance is based on a multiparameter analysis (T2-weighting and T1-weighting, DWI, and postcontrast acquisition). This multiparameter approach amplifies the contrast resolution. It has, also, permitted to differentiate scar tissue (after laser resection) from submucosal recurrent disease. In addition, DWI sequences have the potential of a more precise discrimination of peritumoral edema from neoplastic tissue, which may lead to improve the assessment of paraglottic space invasion. Magnetic resonance of the larynx is technically challenging. The use of surface coils and motion-reducing techniques is critical to achieve adequate image quality. The intrinsic high-contrast resolution is further increased by the integration of information from different sequences. When CT has not been conclusive, magnetic resonance is indicated in the pretreatment local assessment and in the suspicion of submucosal recurrence.

Reproducibility and variability of quantitative magnetic resonance imaging markers in cerebral small vessel disease

PubMed Central

De Guio, François; Jouvent, Eric; Biessels, Geert Jan; Black, Sandra E; Brayne, Carol; Chen, Christopher; Cordonnier, Charlotte; De Leeuw, Frank-Eric; Dichgans, Martin; Doubal, Fergus; Duering, Marco; Dufouil, Carole; Duzel, Emrah; Fazekas, Franz; Hachinski, Vladimir; Ikram, M Arfan; Linn, Jennifer; Matthews, Paul M; Mazoyer, Bernard; Mok, Vincent; Norrving, Bo; O’Brien, John T; Pantoni, Leonardo; Ropele, Stefan; Sachdev, Perminder; Schmidt, Reinhold; Seshadri, Sudha; Smith, Eric E; Sposato, Luciano A; Stephan, Blossom; Swartz, Richard H; Tzourio, Christophe; van Buchem, Mark; van der Lugt, Aad; van Oostenbrugge, Robert; Vernooij, Meike W; Viswanathan, Anand; Werring, David; Wollenweber, Frank; Wardlaw, Joanna M

2016-01-01

Brain imaging is essential for the diagnosis and characterization of cerebral small vessel disease. Several magnetic resonance imaging markers have therefore emerged, providing new information on the diagnosis, progression, and mechanisms of small vessel disease. Yet, the reproducibility of these small vessel disease markers has received little attention despite being widely used in cross-sectional and longitudinal studies. This review focuses on the main small vessel disease-related markers on magnetic resonance imaging including: white matter hyperintensities, lacunes, dilated perivascular spaces, microbleeds, and brain volume. The aim is to summarize, for each marker, what is currently known about: (1) its reproducibility in studies with a scan–rescan procedure either in single or multicenter settings; (2) the acquisition-related sources of variability; and, (3) the techniques used to minimize this variability. Based on the results, we discuss technical and other challenges that need to be overcome in order for these markers to be reliably used as outcome measures in future clinical trials. We also highlight the key points that need to be considered when designing multicenter magnetic resonance imaging studies of small vessel disease. PMID:27170700

Functional magnetic resonance imaging in oncology: state of the art*

PubMed Central

Guimaraes, Marcos Duarte; Schuch, Alice; Hochhegger, Bruno; Gross, Jefferson Luiz; Chojniak, Rubens; Marchiori, Edson

2014-01-01

In the investigation of tumors with conventional magnetic resonance imaging, both quantitative characteristics, such as size, edema, necrosis, and presence of metastases, and qualitative characteristics, such as contrast enhancement degree, are taken into consideration. However, changes in cell metabolism and tissue physiology which precede morphological changes cannot be detected by the conventional technique. The development of new magnetic resonance imaging techniques has enabled the functional assessment of the structures in order to obtain information on the different physiological processes of the tumor microenvironment, such as oxygenation levels, cellularity and vascularity. The detailed morphological study in association with the new functional imaging techniques allows for an appropriate approach to cancer patients, including the phases of diagnosis, staging, response evaluation and follow-up, with a positive impact on their quality of life and survival rate. PMID:25741058

Functional magnetic resonance imaging in oncology: state of the art.

PubMed

Guimaraes, Marcos Duarte; Schuch, Alice; Hochhegger, Bruno; Gross, Jefferson Luiz; Chojniak, Rubens; Marchiori, Edson

2014-01-01

In the investigation of tumors with conventional magnetic resonance imaging, both quantitative characteristics, such as size, edema, necrosis, and presence of metastases, and qualitative characteristics, such as contrast enhancement degree, are taken into consideration. However, changes in cell metabolism and tissue physiology which precede morphological changes cannot be detected by the conventional technique. The development of new magnetic resonance imaging techniques has enabled the functional assessment of the structures in order to obtain information on the different physiological processes of the tumor microenvironment, such as oxygenation levels, cellularity and vascularity. The detailed morphological study in association with the new functional imaging techniques allows for an appropriate approach to cancer patients, including the phases of diagnosis, staging, response evaluation and follow-up, with a positive impact on their quality of life and survival rate.

Multimodal imaging of human cerebellum - merging X-ray phase microtomography, magnetic resonance microscopy and histology

NASA Astrophysics Data System (ADS)

Schulz, Georg; Waschkies, Conny; Pfeiffer, Franz; Zanette, Irene; Weitkamp, Timm; David, Christian; Müller, Bert

2012-11-01

Imaging modalities including magnetic resonance imaging and X-ray computed tomography are established methods in daily clinical diagnosis of human brain. Clinical equipment does not provide sufficient spatial resolution to obtain morphological information on the cellular level, essential for applying minimally or non-invasive surgical interventions. Therefore, generic data with lateral sub-micrometer resolution have been generated from histological slices post mortem. Sub-cellular spatial resolution, lost in the third dimension as a result of sectioning, is obtained using magnetic resonance microscopy and micro computed tomography. We demonstrate that for human cerebellum grating-based X-ray phase tomography shows complementary contrast to magnetic resonance microscopy and histology. In this study, the contrast-to-noise values of magnetic resonance microscopy and phase tomography were comparable whereas the spatial resolution in phase tomography is an order of magnitude better. The registered data with their complementary information permit the distinct segmentation of tissues within the human cerebellum.

Multiparametric magnetic resonance imaging for the assessment of non-alcoholic fatty liver disease severity.

PubMed

Pavlides, Michael; Banerjee, Rajarshi; Tunnicliffe, Elizabeth M; Kelly, Catherine; Collier, Jane; Wang, Lai Mun; Fleming, Kenneth A; Cobbold, Jeremy F; Robson, Matthew D; Neubauer, Stefan; Barnes, Eleanor

2017-07-01

The diagnosis of non-alcoholic steatohepatitis and fibrosis staging are central to non-alcoholic fatty liver disease assessment. We evaluated multiparametric magnetic resonance in the assessment of non-alcoholic steatohepatitis and fibrosis using histology as standard in non-alcoholic fatty liver disease. Seventy-one patients with suspected non-alcoholic fatty liver disease were recruited within 1 month of liver biopsy. Magnetic resonance data were used to define the liver inflammation and fibrosis score (LIF 0-4). Biopsies were assessed for steatosis, lobular inflammation, ballooning and fibrosis and classified as non-alcoholic steatohepatitis or simple steatosis, and mild or significant (Activity ≥2 and/or Fibrosis ≥2 as defined by the Fatty Liver Inhibition of Progression consortium) non-alcoholic fatty liver disease. Transient elastography was also performed. Magnetic resonance success rate was 95% vs 59% for transient elastography (P<.0001). Fibrosis stage on biopsy correlated with liver inflammation and fibrosis (r s =.51, P<.0001). The area under the receiver operating curve using liver inflammation and fibrosis for the diagnosis of cirrhosis was 0.85. Liver inflammation and fibrosis score for ballooning grades 0, 1 and 2 was 1.2, 2.7 and 3.5 respectively (P<.05) with an area under the receiver operating characteristic curve of 0.83 for the diagnosis of ballooning. Patients with steatosis had lower liver inflammation and fibrosis (1.3) compared to patients with non-alcoholic steatohepatitis (3.0) (P<.0001); area under the receiver operating characteristic curve for the diagnosis of non-alcoholic steatohepatitis was 0.80. Liver inflammation and fibrosis scores for patients with mild and significant non-alcoholic fatty liver disease were 1.2 and 2.9 respectively (P<.0001). The area under the receiver operating characteristic curve of liver inflammation and fibrosis for the diagnosis of significant non-alcoholic fatty liver disease was 0

The economic effect of using magnetic resonance imaging and magnetic resonance ultrasound fusion biopsy for prostate cancer diagnosis.

PubMed

Hutchinson, Ryan C; Costa, Daniel N; Lotan, Yair

2016-07-01

Prostate magnetic resonance imaging (MRI) is a maturing imaging modality that has been used to improve detection and staging of prostate cancer. The goal of this review is to evaluate the economic effect of the use of MRI and MRI fusion in the diagnosis of prostate cancer. A literature review was used to identify articles regarding efficacy and cost of MRI and MRI-guided biopsies. There are currently a limited number of studies evaluating cost of incorporating MRI into clinical practice. These studies are primarily models projecting cost estimates based on meta-analyses of the literature. There is considerable variance in the effectiveness of MRI-guided biopsies, both cognitive and fusion, based on user experience, type of MRI (3T vs. 1.5T), use of endorectal coil and type of scoring system for abnormalities such that there is still potential for improvement in accuracy. There is also variability in assumed costs of incorporating MRI into clinical practice. The addition of MRI to the diagnostic algorithm for prostate cancer has caused a shift in how we understand the disease and in what tumors are found on initial and repeat biopsies. Further risk stratification may allow more men to pursue noncurative therapy, which in and of itself is cost-effective in properly selected men. As prostate cancer care comes under increasing scrutiny on a national level, there is pressure on providers to be more accurate in their diagnoses. This in turn can lead to additional testing including Multiparametric MRI, which adds upfront cost. Whether the additional cost of prostate MRI is warranted in detection of prostate cancer is an area of intense research. Copyright © 2016 Elsevier Inc. All rights reserved.

Diffusion-weighted Imaging Is a Sensitive and Specific Magnetic Resonance Sequence in the Diagnosis of Ankylosing Spondylitis.

PubMed

Bradbury, Linda A; Hollis, Kelly A; Gautier, Benoît; Shankaranarayana, Sateesh; Robinson, Philip C; Saad, Nivene; Lê Cao, Kim-Anh; Brown, Matthew A

2018-06-01

We tested the discriminatory capacity of diffusion-weighted magnetic resonance imaging (DWI) and its potential as an objective measure of treatment response to tumor necrosis factor inhibition in ankylosing spondylitis (AS). Three cohorts were studied prospectively: (1) 18 AS patients with Bath Ankylosing Spondylitis Disease Activity Index > 4, and erythrocyte sedimentation rate > 25 and/or C-reactive protein > 10 meeting the modified New York criteria for AS; (2) 20 cases of nonradiographic axial spondyloarthritis (nr-axSpA) as defined by the Assessment of Spondyloarthritis international Society (ASAS) criteria; and (3) 20 non-AS patients with chronic low back pain, aged between 18 and 45 years, who did not meet the imaging arm of the ASAS criteria for axSpA. Group 1 patients were studied prior to and following adalimumab treatment. Patients were assessed by DWI and conventional magnetic resonance imaging (MRI), and standard nonimaging measures. At baseline, in contrast to standard nonimaging measures, DWI apparent diffusion coefficient (ADC) values showed good discriminatory performance [area under the curve (AUC) > 80% for Group 1 or 2 compared with Group 3]. DWI ADC values were significantly lower posttreatment (0.45 ± 0.433 before, 0.154 ± 0.23 after, p = 0.0017), but had modest discriminating capacity comparing pre- and posttreatment measures (AUC = 68%). This performance was similar to the manual Spondyloarthritis Research Consortium of Canada (SPARCC) scoring system. DWI is informative for diagnosis of AS and nr-axSpA, and has moderate utility in assessment of disease activity or treatment response, with performance similar to that of the SPARCC MRI score.

Magnetic resonance imaging in evaluating workers' compensation patients.

PubMed

Babbel, Daniel; Rayan, Ghazi

2012-04-01

We studied the utility of magnetic resonance imaging (MRI) studies for workers' compensation patients with hand conditions in which the referring doctor obtained the images. We compared the MRI findings with the eventual clinical findings. We also investigated the approximate cost of these MRI studies. We retrospectively reviewed the charts of all workers' compensation patients seen in a hand and upper extremity practice over the course of 3 years. We selected patients who had MRI studies of the affected upper extremities before referral to the senior author (G.R.). We reviewed the charts for information regarding demographics, referral diagnoses, MRI diagnoses made by the radiologist, the area of the upper extremity studied, and eventual clinical diagnoses by the senior author. We made a determination as to whether a hand surgeon could have adequately diagnosed and treated the patients' conditions without the imaging studies. We also investigated the cost associated with these MRIs. We included 62 patients with a total of 67 MRI scans in this study. The MRI studies did not contribute to clinically diagnosing the patients' conditions in any of the cases we reviewed. The hand surgeon's clinical diagnosis disagreed with the radiologist's MRI diagnosis in 63% of patients. The MRI was unnecessary to arrive at the clinical diagnosis and did not influence the treatment offered for any of the 62 patients. The total cost for the 67 non-contrast MRI studies was approximately $53,000. Costly imaging studies are frequently done to determine the validity of a patient's reported problems; unfortunately, these tests are frequently unnecessary and waste resources. Magnetic resonance imaging scans may not be the standard for accurate diagnosis and can misdirect care. Therapeutic III. Copyright © 2012 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Magnetic resonance imaging biomarkers for the early diagnosis of Alzheimer's disease: a machine learning approach.

PubMed

Salvatore, Christian; Cerasa, Antonio; Battista, Petronilla; Gilardi, Maria C; Quattrone, Aldo; Castiglioni, Isabella

2015-01-01

Determination of sensitive and specific markers of very early AD progression is intended to aid researchers and clinicians to develop new treatments and monitor their effectiveness, as well as to lessen the time and cost of clinical trials. Magnetic Resonance (MR)-related biomarkers have been recently identified by the use of machine learning methods for the in vivo differential diagnosis of AD. However, the vast majority of neuroimaging papers investigating this topic are focused on the difference between AD and patients with mild cognitive impairment (MCI), not considering the impact of MCI patients who will (MCIc) or not convert (MCInc) to AD. Morphological T1-weighted MRIs of 137 AD, 76 MCIc, 134 MCInc, and 162 healthy controls (CN) selected from the Alzheimer's disease neuroimaging initiative (ADNI) cohort, were used by an optimized machine learning algorithm. Voxels influencing the classification between these AD-related pre-clinical phases involved hippocampus, entorhinal cortex, basal ganglia, gyrus rectus, precuneus, and cerebellum, all critical regions known to be strongly involved in the pathophysiological mechanisms of AD. Classification accuracy was 76% AD vs. CN, 72% MCIc vs. CN, 66% MCIc vs. MCInc (nested 20-fold cross validation). Our data encourage the application of computer-based diagnosis in clinical practice of AD opening new prospective in the early management of AD patients.

Dental materials and magnetic resonance imaging.

PubMed

Hubálková, Hana; Hora, Karel; Seidl, Zdenek; Krásenský, Jan

2002-09-01

The objective of this investigation was to evaluate the reaction of selected dental materials in the magnetic field of a magnetic resonance imaging device to determine a possible health risk. The following dental materials were tested in vitro during magnetic resonance imaging: 15 dental alloys, four dental implants, one surgical splint and two wires for fixation of maxillofacial fractures. Possible artefacts (corresponding with magnetic properties), heating and force effects were tested. Results concerning movement and heating were in agreement with the literature. The artefacts seen were significant: for the surgical splint, a spherical artefact with a diameter of 55 mm; for the wires, up to 22 mm; and for the dental blade implant, an artefact of 28 x 20 mm. The results of our tests of selected dental appliances indicate that their presence in the human organism is safe for patients undergoing magnetic resonance imaging procedures. The presence of artefacts can substantially influence the magnetic resonance imaging results.

[Magnetic resonance compatibility research for coronary mental stents].

PubMed

Wang, Ying; Liu, Li; Wang, Shuo; Shang, Ruyao; Wang, Chunren

2015-01-01

The objective of this article is to research magnetic resonance compatibility for coronary mental stents, and to evaluate the magnetic resonance compatibility based on laboratory testing results. Coronary stents magnetic resonance compatibility test includes magnetically induced displacement force test, magnetically induced torque test, radio frequency induced heating and evaluation of MR image. By magnetic displacement force and torque values, temperature, and image distortion values to determine metal coronary stent demagnetization effect. The methods can be applied to test magnetic resonance compatibility for coronary mental stents and evaluate its demagnetization effect.

MRI (Magnetic Resonance Imaging)

MedlinePlus

... IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) Safety Electromagnetic Modeling Related ... Resonance Imaging Equipment in Clinical Use (March 2015) FDA/CDER: Information on Gadolinium-Based Contrast Agents Safety ...

Torque-mixing magnetic resonance spectroscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Losby, Joseph; Fani Sani, Fatemeh; Grandmont, Dylan T.; Diao, Zhu; Belov, Miro; Burgess, Jacob A.; Compton, Shawn R.; Hiebert, Wayne K.; Vick, Doug; Mohammad, Kaveh; Salimi, Elham; Bridges, Gregory E.; Thomson, Douglas J.; Freeman, Mark R.

2016-10-01

An optomechanical platform for magnetic resonance spectroscopy will be presented. The method relies on frequency mixing of orthogonal RF fields to yield a torque amplitude (arising from the transverse component of a precessing dipole moment, in analogy to magnetic resonance detection by electromagnetic induction) on a miniaturized resonant mechanical torsion sensor. In contrast to induction, the method is fully broadband and allows for simultaneous observation of the equilibrium net magnetic moment alongside the associated magnetization dynamics. To illustrate the method, comprehensive electron spin resonance spectra of a mesoscopic, single-crystal YIG disk at room temperature will be presented, along with situations where torque spectroscopy can offer complimentary information to existing magnetic resonance detection techniques. The authors are very grateful for support from NSERC, CRC, AITF, and NINT. Reference: Science 350, 798 (2015).

Magnetic Resonance Imaging of Nonneoplastic Musculoskeletal Pathologies in the Pelvis.

PubMed

Alapati, Sindhura; Wadhwa, Vibhor; Komarraju, Aparna; Guidry, Carey; Pandey, Tarun

2017-06-01

Musculoskeletal pathologies in the pelvis encompass a wide variety of lesions including femoroacetabular impingement, athletic pubalgia, ischiofemoral impingement, and apophyseal avulsion injuries. Magnetic resonance imaging is the noninvasive imaging modality of choice for the diagnosis and management of these lesions. In this article, the authors discuss the nonneoplastic musculoskeletal lesions in the pelvis, with illustrations and relevant case examples. Copyright © 2017 Elsevier Inc. All rights reserved.

Magnetic resonance imaging-directed transperineal limited-mapping prostatic biopsies to diagnose prostate cancer: a Scottish experience.

PubMed

Mukherjee, Ankur; Morton, Simon; Fraser, Sioban; Salmond, Jonathan; Baxter, Grant; Leung, Hing Y

2014-11-01

Transperineal prostatic biopsy is firmly established as an important tool in the diagnosis of prostate cancer. The benefit of additional imaging (magnetic resonance imaging) to target biopsy remains to be fully addressed. Using a cohort of consecutive patients undergoing transperineal template mapping biopsies, we studied positive biopsies in the context of magnetic resonance imaging findings and examined the accuracy of magnetic resonance imaging in predicting the location of transperineal template mapping biopsies-detected prostate cancer. Forty-four patients (mean age: 65 years, range 53-78) underwent transperineal template mapping biopsies. Thirty-four patients had 1-2 and 10 patients had ≥3 previous transrectal ultrasound scan-guided biopsies. The mean prostate-specific antigen was 15 ng/mL (range 2.5-79 ng/mL). High-grade prostatic intraepithelial neoplasia was found in 12 (27%) patients and prostate cancer with Gleason <7, 7 and >7 in 13, 10 and 8 patients, respectively. Suspicious lesions on magnetic resonance imaging scans were scored from 1 to 5. In 28 patients, magnetic resonance imaging detected lesions with score ≥3. Magnetic resonance imaging correctly localised transperineal template mapping biopsies-detected prostate cancer in a hemi-gland approach, particularly in a right to left manner (79% positive prediction rate), but not in a quadrant approach (33% positive prediction rate). Our findings support the notion of magnetic resonance imaging-based selection of patients for transperineal template mapping biopsies and that lesions revealed by magnetic resonance imaging are likely useful for targeted biopsies. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Wide-range nuclear magnetic resonance detector

NASA Technical Reports Server (NTRS)

Sturman, J. C.; Jirberg, R. J.

1972-01-01

Compact and easy to use solid state nuclear magnetic resonance detector is designed for measuring field strength to 20 teslas in cryogenically cooled magnets. Extremely low noise and high sensitivity make detector applicable to nearly all types of analytical nuclear magnetic resonance measurements and can be used in high temperature and radiation environments.

Human tooth and root canal morphology reconstruction using magnetic resonance imaging.

PubMed

Drăgan, Oana Carmen; Fărcăşanu, Alexandru Ştefan; Câmpian, Radu Septimiu; Turcu, Romulus Valeriu Flaviu

2016-01-01

Visualization of the internal and external root canal morphology is very important for a successful endodontic treatment; however, it seems to be difficult considering the small size of the tooth and the complexity of the root canal system. Film-based or digital conventional radiographic techniques as well as cone beam computed tomography provide limited information on the dental pulp anatomy or have harmful effects. A new non-invasive diagnosis tool is magnetic resonance imaging, due to its ability of imaging both hard and soft tissues. The aim of this study was to demonstrate magnetic resonance imaging to be a useful tool for imaging the anatomic conditions of the external and internal root canal morphology for endodontic purposes. The endodontic system of one freshly extracted wisdom tooth, chosen for its well-known anatomical variations, was mechanically shaped using a hybrid technique. After its preparation, the tooth was immersed into a recipient with saline solution and magnetic resonance imaged immediately. A Bruker Biospec magnetic resonance imaging scanner operated at 7.04 Tesla and based on Avance III radio frequency technology was used. InVesalius software was employed for the 3D reconstruction of the tooth scanned volume. The current ex-vivo experiment shows the accurate 3D volume rendered reconstruction of the internal and external morphology of a human extracted and endodontically treated tooth using a dataset of images acquired by magnetic resonance imaging. The external lingual and vestibular views of the tooth as well as the occlusal view of the pulp chamber, the access cavity, the distal canal opening on the pulp chamber floor, the coronal third of the root canals, the degree of root separation and the apical fusion of the two mesial roots, details of the apical region, root canal curvatures, furcal region and interradicular root grooves could be clearly bordered. Magnetic resonance imaging offers 3D image datasets with more information than the

Utility of ultrasound and magnetic resonance imaging in prenatal diagnosis of placenta accreta: A prospective study.

PubMed

Satija, Bhawna; Kumar, Sanyal; Wadhwa, Leena; Gupta, Taru; Kohli, Supreethi; Chandoke, Rajkumar; Gupta, Pratibha

2015-01-01

Placenta accreta is the abnormal adherence of the placenta to the uterine wall and the most common cause for emergency postpartum hysterectomy. Accurate prenatal diagnosis of affected pregnancies allows optimal obstetric management. To summarize our experience in the antenatal diagnosis of placenta accreta on imaging in a tertiary care setup. To compare the accuracy of ultrasound (USG) with color Doppler (CDUS) and magnetic resonance imaging (MRI) in prenatal diagnosis of placenta accreta. Prospective study in a tertiary care setup. A prospective study was conducted on pregnant females with high clinical risk of placenta accreta. Antenatal diagnosis was established based on CDUS and MRI. The imaging findings were compared with final diagnosis at the time of delivery and/or pathologic examination. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for both CDUS and MRI. The sensitivity and specificity values of USG and MRI were compared by the McNemar test. Thirty patients at risk of placenta accreta underwent both CDUS and MRI. Eight cases of placenta accreta were identified (3 vera, 4 increta, and 1 percreta). All patients had history of previous cesarean section. Placenta previa was present in seven out of eight patients. USG correctly identified the presence of placenta accreta in seven out of eight patients (87.5% sensitivity) and the absence of placenta accreta in 19 out of 22 patients (86.4% specificity). MRI correctly identified the presence of placenta accreta in 6 out of 8 patients (75.0% sensitivity) and absence of placenta accreta in 17 out of 22 patients (77.3% specificity). There were no statistical differences in sensitivity (P = 1.00) and specificity (P = 0.687) between USG and MRI. Both USG and MRI have fairly good sensitivity for prenatal diagnosis of placenta accreta; however, specificity does not appear to be as good as reported in other studies. Both modalities have complimentary

Utility of ultrasound and magnetic resonance imaging in prenatal diagnosis of placenta accreta: A prospective study

PubMed Central

Satija, Bhawna; Kumar, Sanyal; Wadhwa, Leena; Gupta, Taru; Kohli, Supreethi; Chandoke, Rajkumar; Gupta, Pratibha

2015-01-01

Context: Placenta accreta is the abnormal adherence of the placenta to the uterine wall and the most common cause for emergency postpartum hysterectomy. Accurate prenatal diagnosis of affected pregnancies allows optimal obstetric management. Aims: To summarize our experience in the antenatal diagnosis of placenta accreta on imaging in a tertiary care setup. To compare the accuracy of ultrasound (USG) with color Doppler (CDUS) and magnetic resonance imaging (MRI) in prenatal diagnosis of placenta accreta. Settings and Design: Prospective study in a tertiary care setup. Materials and Methods: A prospective study was conducted on pregnant females with high clinical risk of placenta accreta. Antenatal diagnosis was established based on CDUS and MRI. The imaging findings were compared with final diagnosis at the time of delivery and/or pathologic examination. Statistical Analysis Used: The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for both CDUS and MRI. The sensitivity and specificity values of USG and MRI were compared by the McNemar test. Results: Thirty patients at risk of placenta accreta underwent both CDUS and MRI. Eight cases of placenta accreta were identified (3 vera, 4 increta, and 1 percreta). All patients had history of previous cesarean section. Placenta previa was present in seven out of eight patients. USG correctly identified the presence of placenta accreta in seven out of eight patients (87.5% sensitivity) and the absence of placenta accreta in 19 out of 22 patients (86.4% specificity). MRI correctly identified the presence of placenta accreta in 6 out of 8 patients (75.0% sensitivity) and absence of placenta accreta in 17 out of 22 patients (77.3% specificity). There were no statistical differences in sensitivity (P = 1.00) and specificity (P = 0.687) between USG and MRI. Conclusions: Both USG and MRI have fairly good sensitivity for prenatal diagnosis of placenta accreta; however

Magnetic resonance spectroscopy of the human brain

NASA Astrophysics Data System (ADS)

Strózik-Kotlorz, D.

2014-01-01

I give a brief description of the magnetic resonance spectroscopy (MRS) in the human brain examinations. MRS allows a noninvasive chemical analysis of the brain using a standard high field MR system. Nowadays, the dominant form of MR brain spectroscopy is proton spectroscopy. Two main techniques of MRS, which utilize the chemical shift of metabolites in the external magnetic field, are SVS (single voxel) and CSI (single slice). The major peaks in the spectrum of a normal brain include NAA, Cr, Cho and m-Ins, which are neuronal, energetic, membrane turnover and glial markers, respectively. In disease, two pathological metabolites can be found in the brain spectra: Lac, which is end product of anaerobic glycolysis and Lip, which is a marker of membrane breakdown, occurring in necrosis. The common way to analyze clinical spectra is to determine metabolite ratios, e.g. NAA/Cr, Cho/Cr, Cho/NAA. This analysis permits a safe and noninvasive examination of the brain tissue as each disease state has its own characteristic spectroscopic image. MRS is a valuable diagnostic tool in such clinical applications as detecting brain tumors and differentiating tumors from inflammatory and infectious processes. Proton MRS is also very helpful in diagnostic of ischemic lesions, Alzheimer's disease and hepatic encephalopathy. The MRS brain spectra should always be correlated with the Magnetic Resonance Imaging (MRI) results and alone cannot make neurological diagnosis.

Magnetic Resonance Safety

PubMed Central

Sammet, Steffen

2016-01-01

Magnetic Resonance Imaging (MRI) has a superior soft-tissue contrast compared to other radiological imaging modalities and its physiological and functional applications have led to a significant increase in MRI scans worldwide. A comprehensive MRI safety training to protect patients and other healthcare workers from potential bio-effects and risks of the magnetic fields in an MRI suite is therefore essential. The knowledge of the purpose of safety zones in an MRI suite as well as MRI appropriateness criteria is important for all healthcare professionals who will work in the MRI environment or refer patients for MRI scans. The purpose of this article is to give an overview of current magnetic resonance safety guidelines and discuss the safety risks of magnetic fields in an MRI suite including forces and torque of ferromagnetic objects, tissue heating, peripheral nerve stimulation and hearing damages. MRI safety and compatibility of implanted devices, MRI scans during pregnancy and the potential risks of MRI contrast agents will also be discussed and a comprehensive MRI safety training to avoid fatal accidents in an MRI suite will be presented. PMID:26940331

Use of magnetic resonance cholangiography in the diagnosis of choledocholithiasis: prospective comparison with a reference imaging method

PubMed Central

Zidi, S; Prat, F; Le Guen, O; Rondeau, Y; Rocher, L; Fritsch, J; Choury, A; Pelletier, G

1999-01-01

Background—Magnetic resonance cholangiography (MRC) is a new technique for non-invasive imaging of the biliary tract. 
Aim—To assess the results of MRC in patients with suspected bile duct stones as compared with those obtained with reference imaging methods. 
Patients/Methods—70 patients (34 men and 36 women, mean (SD) age 71 (15.5) years; median 75) with suspected bile duct stones were included (cholangitis, 33; pancreatitis, three; suspected post-cholecystectomy choledocholithiasis, nine; cholestasis, six; stones suspected on ultrasound or computed tomography scan, 19). MR cholangiograms with two dimensional turbo spin echo sequences were acquired. Endoscopic retrograde cholangiography with or without sphincterotomy (n = 63), endosonography (n = 5), or intraoperative cho- langiography (n = 2) were the reference imaging techniques used for the study and were performed within 12 hours of MRC. Radiologists were blinded to the results of endoscopic retrograde cholangiography and previous investigations. 
Results—49 patients (70%) had bile duct stones on reference imaging (common bile duct, 44, six of which impacted in the papilla; intrahepatic, four; cystic duct stump, one). Stone size ranged from 1 to 20 mm (mean 6.1, median 5.5). Twenty seven patients (55%) had bile duct stones smaller than 6 mm. MRC diagnostic accuracy for bile duct lithiasis was: sensitivity, 57.1%; specificity, 100%; positive predictive value, 100%; negative predictive value, 50%. 
Conclusions—Stones smaller than 6 mm are still often missed by MRC when standard equipment is used. The general introduction of new technical improvements is needed before this method can be considered reliable for the diagnosis of bile duct stones. 

 Keywords: bile duct calculi; endoscopic retrograde cholangiography; magnetic resonance cholangiography PMID:9862837

Tissue discrimination in magnetic resonance imaging of the rotator cuff

NASA Astrophysics Data System (ADS)

Meschino, G. J.; Comas, D. S.; González, M. A.; Capiel, C.; Ballarin, V. L.

2016-04-01

Evaluation and diagnosis of diseases of the muscles within the rotator cuff can be done using different modalities, being the Magnetic Resonance the method more widely used. There are criteria to evaluate the degree of fat infiltration and muscle atrophy, but these have low accuracy and show great variability inter and intra observer. In this paper, an analysis of the texture features of the rotator cuff muscles is performed to classify them and other tissues. A general supervised classification approach was used, combining forward-search as feature selection method with kNN as classification rule. Sections of Magnetic Resonance Images of the tissues of interest were selected by specialist doctors and they were considered as Gold Standard. Accuracies obtained were of 93% for T1-weighted images and 92% for T2-weighted images. As an immediate future work, the combination of both sequences of images will be considered, expecting to improve the results, as well as the use of other sequences of Magnetic Resonance Images. This work represents an initial point for the classification and quantification of fat infiltration and muscle atrophy degree. From this initial point, it is expected to make an accurate and objective system which will result in benefits for future research and for patients’ health.

Traumatic Brain Injury Diffusion Magnetic Resonance Imaging Research Roadmap Development Project

DTIC Science & Technology

2012-10-01

Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT . Traumatic Brain Injury ( TBI ) is a public health problem of immense magnitude and...immediate importance that has become endemic among military personnel and veterans. Imaging biomarkers of TBI are needed to support diagnosis and therapy...and to predict TBI consequences while avoiding further injury. Diffusion magnetic resonance imaging has potential to become the non-invasive tool

Use of radiography, computed tomography and magnetic resonance imaging for evaluation of navicular syndrome in the horse.

PubMed

Widmer, W R; Buckwalter, K A; Fessler, J F; Hill, M A; VanSickle, D C; Ivancevich, S

2000-01-01

Radiographic evaluation of navicular syndrome is problematic because of its inconsistent correlation with clinical signs. Scintigraphy often yields false positive and false negative results and diagnostic ultrasound is of limited value. Therefore, we assessed the use of computed tomography and magnetic resonance imaging in a horse with clinical and radiographic signs of navicular syndrome. Cadaver specimens were examined with spiral computed tomographic and high-field magnetic resonance scanners and images were correlated with pathologic findings. Radiographic changes consisted of bony remodeling, which included altered synovial fossae, increased medullary opacity, cyst formation and shape change. These osseous changes were more striking and more numerous on computed tomographic and magnetic resonance images. They were most clearly defined with computed tomography. Many osseous changes seen with computed tomography and magnetic resonance imaging were not radiographically evident. Histologically confirmed soft tissue alterations of the deep digital flexor tendon, impar ligament and marrow were identified with magnetic resonance imaging, but not with conventional radiography. Because of their multiplanar capability and tomographic nature, computed tomography and magnetic resonance imaging surpass conventional radiography for navicular imaging, facilitating earlier, more accurate diagnosis. Current advances in imaging technology should make these imaging modalities available to equine practitioners in the future.

Comprehensive Review on Magnetic Resonance Imaging in Alzheimer's Disease.

PubMed

Dona, Olga; Thompson, Jeff; Druchok, Cheryl

2016-01-01

Alzheimer's disease (AD) is the most common cause of dementia in the elderly. However, definitive diagnosis of AD is only achievable postmortem and currently relies on clinical neurological evaluation. Magnetic resonance imaging (MRI) can evaluate brain changes typical of AD, including brain atrophy, presence of amyloid β (Aβ) plaques, and functional and biochemical abnormalities. Structural MRI (sMRI) has historically been used to assess the inherent brain atrophy present in AD. However, new techniques have recently emerged that have refined sMRI into a more precise tool to quantify the thickness and volume of AD-sensitive cerebral structures. Aβ plaques, a defining pathology of AD, are widely believed to contribute to the progressive cognitive decline in AD, but accurate assessment is only possible on autopsy. In vivo MRI of plaques, although currently limited to mouse models of AD, is a very promising technique. Measuring changes in activation and connectivity in AD-specific regions of the brain can be performed with functional MRI (fMRI). To help distinguish AD from diseases with similar symptoms, magnetic resonance spectroscopy (MRS) can be used to look for differing metabolite concentrations in vivo. Together, these MR techniques, evaluating various brain changes typical of AD, may help to provide a more definitive diagnosis and ease the assessment of the disease over time, noninvasively.

Magnetic resonance imaging in laboratory petrophysical core analysis

NASA Astrophysics Data System (ADS)

Mitchell, J.; Chandrasekera, T. C.; Holland, D. J.; Gladden, L. F.; Fordham, E. J.

2013-05-01

Magnetic resonance imaging (MRI) is a well-known technique in medical diagnosis and materials science. In the more specialized arena of laboratory-scale petrophysical rock core analysis, the role of MRI has undergone a substantial change in focus over the last three decades. Initially, alongside the continual drive to exploit higher magnetic field strengths in MRI applications for medicine and chemistry, the same trend was followed in core analysis. However, the spatial resolution achievable in heterogeneous porous media is inherently limited due to the magnetic susceptibility contrast between solid and fluid. As a result, imaging resolution at the length-scale of typical pore diameters is not practical and so MRI of core-plugs has often been viewed as an inappropriate use of expensive magnetic resonance facilities. Recently, there has been a paradigm shift in the use of MRI in laboratory-scale core analysis. The focus is now on acquiring data in the laboratory that are directly comparable to data obtained from magnetic resonance well-logging tools (i.e., a common physics of measurement). To maintain consistency with well-logging instrumentation, it is desirable to measure distributions of transverse (T2) relaxation time-the industry-standard metric in well-logging-at the laboratory-scale. These T2 distributions can be spatially resolved over the length of a core-plug. The use of low-field magnets in the laboratory environment is optimal for core analysis not only because the magnetic field strength is closer to that of well-logging tools, but also because the magnetic susceptibility contrast is minimized, allowing the acquisition of quantitative image voxel (or pixel) intensities that are directly scalable to liquid volume. Beyond simple determination of macroscopic rock heterogeneity, it is possible to utilize the spatial resolution for monitoring forced displacement of oil by water or chemical agents, determining capillary pressure curves, and estimating

Noncontrast Magnetic Resonance Lymphography.

PubMed

Arrivé, Lionel; Derhy, Sarah; El Mouhadi, Sanaâ; Monnier-Cholley, Laurence; Menu, Yves; Becker, Corinne

2016-01-01

Different imaging techniques have been used for the investigation of the lymphatic channels and lymph glands. Noncontrast magnetic resonance (MR) lymphography has significant advantages in comparison with other imaging modalities. Noncontrast MR lymphography uses very heavily T2-weighted fast spin echo sequences which obtain a nearly complete signal loss in tissue background and specific display of lymphatic vessels with a long T2 relaxation time. The raw data can be processed with different algorithms such as maximum intensity projection algorithm to obtain an anatomic representation. Standard T2-weighted MR images easily demonstrate the location of edema. It appears as subcutaneous infiltration of soft tissue with a classical honeycomb pattern. True collection around the muscular area may be demonstrated in case of severe lymphedema. Lymph nodes may be normal in size, number, and signal intensity; in other cases, lymph nodes may be smaller in size or number of lymph nodes may be restricted. MR lymphography allows a classification of lymphedema in aplasia (no collecting vessels demonstrated); hypoplasia (a small number of lymphatic vessels), and numerical hyperplasia or hyperplasia (with an increased number of lymphatic vessels of greater and abnormal diameter). Noncontrast MR lymphography is a unique noninvasive imaging modality for the diagnosis of lymphedema. It can be used for positive diagnosis, differential diagnosis, and specific evaluation of lymphedema severity. It may also be used for follow-up evaluation after treatment. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Automated Modular Magnetic Resonance Imaging Clinical Decision Support System (MIROR): An Application in Pediatric Cancer Diagnosis.

PubMed

Zarinabad, Niloufar; Meeus, Emma M; Manias, Karen; Foster, Katharine; Peet, Andrew

2018-05-02

Advances in magnetic resonance imaging and the introduction of clinical decision support systems has underlined the need for an analysis tool to extract and analyze relevant information from magnetic resonance imaging data to aid decision making, prevent errors, and enhance health care. The aim of this study was to design and develop a modular medical image region of interest analysis tool and repository (MIROR) for automatic processing, classification, evaluation, and representation of advanced magnetic resonance imaging data. The clinical decision support system was developed and evaluated for diffusion-weighted imaging of body tumors in children (cohort of 48 children, with 37 malignant and 11 benign tumors). Mevislab software and Python have been used for the development of MIROR. Regions of interests were drawn around benign and malignant body tumors on different diffusion parametric maps, and extracted information was used to discriminate the malignant tumors from benign tumors. Using MIROR, the various histogram parameters derived for each tumor case when compared with the information in the repository provided additional information for tumor characterization and facilitated the discrimination between benign and malignant tumors. Clinical decision support system cross-validation showed high sensitivity and specificity in discriminating between these tumor groups using histogram parameters. MIROR, as a diagnostic tool and repository, allowed the interpretation and analysis of magnetic resonance imaging images to be more accessible and comprehensive for clinicians. It aims to increase clinicians' skillset by introducing newer techniques and up-to-date findings to their repertoire and make information from previous cases available to aid decision making. The modular-based format of the tool allows integration of analyses that are not readily available clinically and streamlines the future developments. ©Niloufar Zarinabad, Emma M Meeus, Karen Manias

Automated Modular Magnetic Resonance Imaging Clinical Decision Support System (MIROR): An Application in Pediatric Cancer Diagnosis

PubMed Central

Zarinabad, Niloufar; Meeus, Emma M; Manias, Karen; Foster, Katharine

2018-01-01

Background Advances in magnetic resonance imaging and the introduction of clinical decision support systems has underlined the need for an analysis tool to extract and analyze relevant information from magnetic resonance imaging data to aid decision making, prevent errors, and enhance health care. Objective The aim of this study was to design and develop a modular medical image region of interest analysis tool and repository (MIROR) for automatic processing, classification, evaluation, and representation of advanced magnetic resonance imaging data. Methods The clinical decision support system was developed and evaluated for diffusion-weighted imaging of body tumors in children (cohort of 48 children, with 37 malignant and 11 benign tumors). Mevislab software and Python have been used for the development of MIROR. Regions of interests were drawn around benign and malignant body tumors on different diffusion parametric maps, and extracted information was used to discriminate the malignant tumors from benign tumors. Results Using MIROR, the various histogram parameters derived for each tumor case when compared with the information in the repository provided additional information for tumor characterization and facilitated the discrimination between benign and malignant tumors. Clinical decision support system cross-validation showed high sensitivity and specificity in discriminating between these tumor groups using histogram parameters. Conclusions MIROR, as a diagnostic tool and repository, allowed the interpretation and analysis of magnetic resonance imaging images to be more accessible and comprehensive for clinicians. It aims to increase clinicians’ skillset by introducing newer techniques and up-to-date findings to their repertoire and make information from previous cases available to aid decision making. The modular-based format of the tool allows integration of analyses that are not readily available clinically and streamlines the future developments. PMID

Diagnosing aneurysmal and unicameral bone cysts with magnetic resonance imaging.

PubMed

Sullivan, R J; Meyer, J S; Dormans, J P; Davidson, R S

1999-09-01

The differential between aneurysmal bone cysts and unicameral bone cysts usually is clear clinically and radiographically. Occasionally there are cases in which the diagnosis is not clear. Because natural history and treatment are different, the ability to distinguish between these two entities before surgery is important. The authors reviewed, in a blinded fashion, the preoperative magnetic resonance images to investigate criteria that could be used to differentiate between the two lesions. All patients had operative or pathologic confirmation of an aneurysmal bone cyst or unicameral bone cyst. The authors analyzed the preoperative magnetic resonance images of 14 patients with diagnostically difficult bone cysts (eight children with unicameral bone cysts and six children with aneurysmal bone cysts) and correlated these findings with diagnosis after biopsy or cyst aspiration and contrast injection. The presence of a double density fluid level within the lesion strongly indicated that the lesion was an aneurysmal bone cyst, rather than a unicameral bone cyst. Other criteria that suggested the lesion was an aneurysmal bone cyst were the presence of septations within the lesion and signal characteristics of low intensity on T1 images and high intensity on T2 images. The authors identified a way of helping to differentiate between aneurysmal bone cysts and unicameral bone cysts on magnetic resonance images. Double density fluid level, septation, and low signal on T1 images and high signal on T2 images strongly suggest the bone cyst in question is an aneurysmal bone cyst, rather than a unicameral bone cyst. This may be helpful before surgery for the child who has a cystic lesion for which radiographic features do not allow a clear differentiation of unicameral bone cyst from aneurysmal bone cyst.

Identification of Warthin tumor: magnetic resonance imaging versus salivary scintigraphy with technetium-99m pertechnetate.

PubMed

Motoori, Ken; Ueda, Takuya; Uchida, Yoshitaka; Chazono, Hideaki; Suzuki, Homare; Ito, Hisao

2005-01-01

The aim of this study was to evaluate the accuracy of technetium-99m (Tc-99m) pertechnetate scintigraphy and magnetic resonance (MR) imaging in the diagnosis of Warthin tumor. Sixteen cases of Warthin tumor and 17 cases of non-Warthin tumor were examined by Tc-99m pertechnetate scintigraphy with lemon juice stimulation and MR imaging, including T1-weighted, T2-weighted, short inversion time inversion recovery, diffusion-weighted, and contrast-enhanced dynamic images. We used the receiver operating characteristic (ROC) curve to evaluate diagnostic accuracy. The mean area under the ROC curves of MR imaging in the diagnosis of Warthin tumor (0.97) was higher than that of Tc-99m pertechnetate scintigraphy (0.88). Magnetic resonance imaging is more useful in the evaluation of Warthin tumor than Tc-99m pertechnetate scintigraphy.

Advanced and Conventional Magnetic Resonance Imaging in Neuropsychiatric Lupus

PubMed Central

Sarbu, Nicolae; Bargalló, Núria; Cervera, Ricard

2015-01-01

Neuropsychiatric lupus is a major diagnostic challenge, and a main cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Magnetic resonance imaging (MRI) is, by far, the main tool for assessing the brain in this disease. Conventional and advanced MRI techniques are used to help establishing the diagnosis, to rule out alternative diagnoses, and recently, to monitor the evolution of the disease. This review explores the neuroimaging findings in SLE, including the recent advances in new MRI methods. PMID:26236469

Unusual scarring patterns on cardiac magnetic resonance imaging: A potentially treatable etiology not to be missed.

PubMed

Jordan, Andrew; Lyne, Jonathan; Wong, Tom

2010-04-01

A case of cardiomyopathy and ventricular tachycardia previously assumed to be idiopathic in origin is described. Investigation with cardiac magnetic resonance imaging prompted the diagnosis and successful treatment of an underlying disorder based on typical scarring patterns seen with late gadolinium enhancement. The present report suggests that clinicians should have a low threshold for actively excluding this condition in patients presenting with cardiomyopathy, even in the absence of other disease features, particularly if typical scarring patterns are found on cardiac magnetic resonance imaging because disease-specific therapy appears to significantly improve both symptoms and prognosis.

Noninvasive Imaging of Early Venous Thrombosis by 19F Magnetic Resonance Imaging With Targeted Perfluorocarbon Nanoemulsions.

PubMed

Temme, Sebastian; Grapentin, Christoph; Quast, Christine; Jacoby, Christoph; Grandoch, Maria; Ding, Zhaoping; Owenier, Christoph; Mayenfels, Friederike; Fischer, Jens W; Schubert, Rolf; Schrader, Jürgen; Flögel, Ulrich

2015-04-21

Noninvasive detection of deep venous thrombi and subsequent pulmonary thromboembolism is a serious medical challenge, since both incidences are difficult to identify by conventional ultrasound techniques. Here, we report a novel technique for the sensitive and specific identification of developing thrombi using background-free 19F magnetic resonance imaging, together with α2-antiplasmin peptide (α2AP)-targeted perfluorocarbon nanoemulsions (PFCs) as contrast agent, which is cross-linked to fibrin by active factor XIII. Ligand functionality was ensured by mild coupling conditions using the sterol-based postinsertion technique. Developing thrombi with a diameter<0.8 mm could be visualized unequivocally in the murine inferior vena cava as hot spots in vivo by simultaneous acquisition of anatomic matching 1H and 19F magnetic resonance images at 9.4 T with both excellent signal-to-noise and contrast-to-noise ratios (71±22 and 17±5, respectively). Furthermore, α2AP-PFCs could be successfully applied for the diagnosis of experimentally induced pulmonary thromboembolism. In line with the reported half-life of factor XIIIa, application of α2AP-PFCs>60 minutes after thrombus induction no longer resulted in detectable 19F magnetic resonance imaging signals. Corresponding results were obtained in ex vivo generated human clots. Thus, α2AP-PFCs can visualize freshly developed thrombi that might still be susceptible to pharmacological intervention. Our results demonstrate that 1H/19F magnetic resonance imaging, together with α2AP-PFCs, is a sensitive, noninvasive technique for the diagnosis of acute deep venous thrombi and pulmonary thromboemboli. Furthermore, ligand coupling by the sterol-based postinsertion technique represents a unique platform for the specific targeting of PFCs for in vivo 19F magnetic resonance imaging. © 2015 American Heart Association, Inc.

The Efficacy of Multiparametric Magnetic Resonance Imaging and Magnetic Resonance Imaging Targeted Biopsy in Risk Classification for Patients with Prostate Cancer on Active Surveillance.

PubMed

Recabal, Pedro; Assel, Melissa; Sjoberg, Daniel D; Lee, Daniel; Laudone, Vincent P; Touijer, Karim; Eastham, James A; Vargas, Hebert A; Coleman, Jonathan; Ehdaie, Behfar

2016-08-01

We determined whether multiparametric magnetic resonance imaging targeted biopsies may replace systematic biopsies to detect higher grade prostate cancer (Gleason score 7 or greater) and whether biopsy may be avoided based on multiparametric magnetic resonance imaging among men with Gleason 3+3 prostate cancer on active surveillance. We identified men with previously diagnosed Gleason score 3+3 prostate cancer on active surveillance who underwent multiparametric magnetic resonance imaging and a followup prostate biopsy. Suspicion for higher grade cancer was scored on a standardized 5-point scale. All patients underwent a systematic biopsy. Patients with multiparametric magnetic resonance imaging regions of interest also underwent magnetic resonance imaging targeted biopsy. The detection rate of higher grade cancer was estimated for different multiparametric magnetic resonance imaging scores with the 3 biopsy strategies of systematic, magnetic resonance imaging targeted and combined. Of 206 consecutive men on active surveillance 135 (66%) had a multiparametric magnetic resonance imaging region of interest. Overall, higher grade cancer was detected in 72 (35%) men. A higher multiparametric magnetic resonance imaging score was associated with an increased probability of detecting higher grade cancer (Wilcoxon-type trend test p <0.0001). Magnetic resonance imaging targeted biopsy detected higher grade cancer in 23% of men. Magnetic resonance imaging targeted biopsy alone missed higher grade cancers in 17%, 12% and 10% of patients with multiparametric magnetic resonance imaging scores of 3, 4 and 5, respectively. Magnetic resonance imaging targeted biopsies increased the detection of higher grade cancer among men on active surveillance compared to systematic biopsy alone. However, a clinically relevant proportion of higher grade cancer was detected using only systematic biopsy. Despite the improved detection of disease progression using magnetic resonance imaging

Ability of Magnetic Resonance Elastography to Assess Taut Bands

PubMed Central

Chen, Qingshan; Basford, Jeffery; An, Kai-Nan

2008-01-01

Background Myofascial taut bands are central to diagnosis of myofascial pain. Despite their importance, we still lack either a laboratory test or imaging technique capable of objectively confirming either their nature or location. This study explores the ability of magnetic resonance elastography to localize and investigate the mechanical properties of myofascial taut bands on the basis of their effects on shear wave propagation. Methods This study was conducted in three phases. The first involved the imaging of taut bands in gel phantoms, the second a finite element modeling of the phantom experiment, and the third a preliminary evaluation involving eight human subjects-four of whom had, and four of whom did not have myofascial pain. Experiments were performed with a 1.5 Tesla magnetic resonance imaging scanner. Shear wave propagation was imaged and shear stiffness was reconstructed using matched filtering stiffness inversion algorithms. Findings The gel phantom imaging and finite element calculation experiments supported our hypothesis that taut bands can be imaged based on its outstanding shear stiffness. The preliminary human study showed a statistically significant 50-100% (p=0.01) increase of shear stiffness in the taut band regions of the involved subjects relative to that of the controls or in nearby uninvolved muscle. Interpretation This study suggests that magnetic resonance elastography may have a potential for objectively characterizing myofascial taut bands that have been up to now detectable only by the clinician's fingers. PMID:18206282

Magnetic resonance spectroscopy of the human brain.

PubMed

Ross, B; Bluml, S

2001-04-01

Magnetic resonance (MR; synonymous with NMR = nuclear magnetic resonance) is a universal physical technique best known for non-invasive detection and anatomical mapping of water protons (H). MR-spectroscopy (MRS) records protons from tissue chemicals other than water, intrinsic phosphorus containing metabolites, sodium, potassium, carbon, nitrogen, and fluorine. MRS is therefore an imaging technique with the potential to record human and animal biochemistry in vivo. As a result of wide availability of MRI equipment in research laboratories and hospitals, MRS is a serious competitor with PET to define normal body composition and its perturbation by pharmacological and pathological events. This article describes practical aspects of in vivo MRS with particular emphasis on the brain, where novel metabolites have been described. A survey of these new aspects of neurochemistry emphasize their practical utility as neuronal and axonal markers, measures of energy status, membrane constituents, and osmolytes, as well as some xenobiotics, such as alcohol. The concept of multinuclear in vivo MRS is illustrated by diagnosis and therapeutic monitoring of several human brain disorders. Although these methods are currently most frequently encountered in human studies, as well as with transgenic and knockout mouse models, MRS adds a new dimension to anatomic and histopathologic descriptions. Copyright 2001 Wiley-Liss, Inc.

Correlation of Electrocardiographic Changes with Cardiac Magnetic Resonance Findings in Patients with Hypertrophic Cardiomyopathy

PubMed Central

Paixão, Gabriela Miana de Mattos; Veronesi, Horácio Eduardo; da Silva, Halsted Alarcão Gomes Pereira; de Alencar Neto, José Nunes; Maldi, Carolina de Paulo; Aguiar Filho, Luciano de Figueiredo; Pinto, Ibrahim Masciarelli Francisco; de França, Francisco Faustino de Albuquerque Carneiro; Correia, Edileide de Barros

2018-01-01

Background Electrocardiogram is the initial test in the investigation of heart disease. Electrocardiographic changes in hypertrophic cardiomyopathy have no set pattern, and correlates poorly with echocardiographic findings. Cardiac magnetic resonance imaging has been gaining momentum for better assessment of hypertrophy, as well as the detection of myocardial fibrosis. Objectives To correlate the electrocardiographic changes with the location of hypertrophy in hypertrophic cardiomyopathy by cardiac magnetic resonance. Methods This descriptive cross-sectional study evaluated 68 patients with confirmed diagnosis of hypertrophic cardiomyopathy by cardiac magnetic resonance. The patients’ electrocardiogram was compared with the location of the greatest myocardial hypertrophy by cardiac magnetic resonance. Statistical significance level of 5% and 95% confidence interval were adopted. Results Of 68 patients, 69% had septal hypertrophy, 21% concentric and 10% apical hypertrophies. Concentric hypertrophy showed the greatest myocardial fibrosis mass (p < 0.001) and the greatest R wave size in D1 (p = 0.0280). The amplitudes of R waves in V5 and V6 (p = 0.0391, p = 0.0148) were higher in apical hypertrophy, with statistical significance. Apical hypertrophy was also associated with higher T wave negativity in D1, V5 and V6 (p < 0.001). Strain pattern was found in 100% of the patients with apical hypertrophy (p < 0.001). Conclusion The location of myocardial hypertrophy by cardiac magnetic resonance can be correlated with electrocardiographic changes, especially for apical hypertrophy. PMID:29538524

New magnetic resonance imaging methods in nephrology

PubMed Central

Zhang, Jeff L.; Morrell, Glen; Rusinek, Henry; Sigmund, Eric; Chandarana, Hersh; Lerman, Lilach O.; Prasad, Pottumarthi Vara; Niles, David; Artz, Nathan; Fain, Sean; Vivier, Pierre H.; Cheung, Alfred K.; Lee, Vivian S.

2013-01-01

Established as a method to study anatomic changes, such as renal tumors or atherosclerotic vascular disease, magnetic resonance imaging (MRI) to interrogate renal function has only recently begun to come of age. In this review, we briefly introduce some of the most important MRI techniques for renal functional imaging, and then review current findings on their use for diagnosis and monitoring of major kidney diseases. Specific applications include renovascular disease, diabetic nephropathy, renal transplants, renal masses, acute kidney injury and pediatric anomalies. With this review, we hope to encourage more collaboration between nephrologists and radiologists to accelerate the development and application of modern MRI tools in nephrology clinics. PMID:24067433

An evaluation of subacute sclerosing panencephalitis patients with diffusion-weighted magnetic resonance imaging.

PubMed

Abuhandan, M; Cece, H; Calik, M; Karakas, E; Dogan, F; Karakas, O

2013-03-01

This study aimed to evaluate the contribution of diffusion weighted magnetic resonance imaging to the diagnosis and staging of subacute sclerosing panencephalitis. The study comprised 26 patients diagnosed with subacute sclerosing panencephalitis at our clinic who were undergoing regular follow-up, and a control group of 18 subjects. Clinical staging was determined by Risk and Haddad classification; 12 at Stage II and 14 at Stage III. Diffusion weighted magnetic resonance images were taken of six areas (frontal, parieto-occipital, cerebellar, deep white matter, thalamus and basal ganglia) and by calculating the apparent diffusion coefficient (ADC) values, and a comparison was made between the stages and with the control group. The ADC values of all the areas of the subacute sclerosing panencephalitis patients were found to be significantly higher compared to the control group (p < 0.05). While the mean ADC values of the deep white matter, basal ganglia, frontal and parieto-occipital areas of the Stage II patients were found to be significant compared to the control group (p < 0.05), there was no significance in the other areas (p > 0.05). The ADC values of all the areas of the Stage III patients were found to be significantly high compared to the Stage II values (p < 0.05). Diffusion weighted magnetic resonance imaging can be used with other diagnostic criteria to confirm diagnosis of subacute sclerosing panencephalitis and to reveal differences between the stages.

Resonance magnetoplasticity in ultralow magnetic fields

NASA Astrophysics Data System (ADS)

Alshits, V. I.; Darinskaya, E. V.; Koldaeva, M. V.; Petrzhik, E. A.

2016-09-01

Resonance relaxation displacements of dislocations in NaCl crystals placed in crossed static and alternating ultralow magnetic fields in the electron paramagnetic resonance scheme are discussed. The Earth's magnetic field B Earth ≈ 50μT and other fields in the range of 26-261 μT are used as the static field. New strongly anisotropic properties of the effect have been revealed. Frequency spectra including numerous peaks of paths at low pump frequencies beginning with 10 kHz, as well as the quartet of equidistant peaks at high frequencies ( 1.4 MHz at B= B Earth), have been measured. The effect is also observed in the pulsed pump field with a resonance duration of 0.5 μs. Resonance changes have been detected in the microhardness of ZnO, triglycine sulfate, and potassium hydrogen phthalate crystals after their exposure in the Earth's magnetic field in the same electron paramagnetic resonance scheme.

[Abdominal ultrasound and magnetic resonance imaging: a comparative study on the non-alcoholic fatty liver disease diagnosis in morbidly obese patients].

PubMed

Chaves, Gabriela Villaça; Pereira, Sílvia Elaine; Saboya, Carlos José; Cortes, Caroline; Ramalho, Rejane

2009-01-01

To evaluate the concordance between abdominal ultrasound and an MRI (Magnetic Resonance Imaging) in the diagnosis of non-alcoholic fatty liver disease (NAFLD), and concordance of these two methods with the histopathological exam. The population studied was comprised of 145 patients with morbid obesity (BMI > or = 40 Kg/m(2)), of both genders. NAFLD diagnosis was performed by MRI and Ultrasound. Liver biopsy was performed in a sub-sample (n=40). To evaluate the concordance of these two methods, the kappa coefficient was used. Concordance between both methods (MRI and Ultrasound) was poor and not significant (Kappa adjusted= 0.27; CI 95%= 0.07-0.39.) Nevertheless a slight concordance was found between diagnosis of NAFLD by ultrasound and the hepatic biopsy, with 83.,3% of concordant results and Kappa adjusted= 0.67.Results of an MRI and the histopathological exam were compared and results showed 53.6% of concordant results and kappa adjusted= 0.07. The concordance found in the diagnosis performed using the ultrasound method and the hepatic biopsy, shows a need to implement and perform more research on the use of ultrasound to validate and reconsider these methods. This would minimize the need to perform biopsies to detect and diagnose such disease.

Interaction of magnetic resonators studied by the magnetic field enhancement

NASA Astrophysics Data System (ADS)

Hou, Yumin

2013-12-01

It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters-shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

Towards endometriosis diagnosis by gadofosveset-trisodium enhanced magnetic resonance imaging.

PubMed

Schreinemacher, Marc H; Backes, Walter H; Slenter, Jos M; Xanthoulea, Sofia; Delvoux, Bert; van Winden, Larissa; Beets-Tan, Regina G; Evers, Johannes L H; Dunselman, Gerard A J; Romano, Andrea

2012-01-01

Endometriosis is defined as the presence of endometrial tissue outside the uterus. It affects 10-15% of women during reproductive age and has a big personal and social impact due to chronic pelvic pain, subfertility, loss of work-hours and medical costs. Such conditions are exacerbated by the fact that the correct diagnosis is made as late as 8-11 years after symptom presentation. This is due to the lack of a reliable non-invasive diagnostic test and the fact that the reference diagnostic standard is laparoscopy (invasive, expensive and not without risks). High-molecular weight gadofosveset-trisodium is used as contrast agent in Magnetic Resonance Imaging (MRI). Since it extravasates from hyperpermeable vessels more easily than from mature blood vessels, this contrast agent detects angiogenesis efficiently. Endometriosis has high angiogenic activity. Therefore, we have tested the possibility to detect endometriosis non-invasively using Dynamic Contrast-Enhanced MRI (DCE-MRI) and gadofosveset-trisodium as a contrast agent in a mouse model. Endometriotic lesions were surgically induced in nine mice by autologous transplantation. Three weeks after lesion induction, mice were scanned by DCE-MRI. Dynamic image analysis showed that the rates of uptake (inwash), persistence and outwash of the contrast agent were different between endometriosis and control tissues (large blood vessels and back muscle). Due to the extensive angiogenesis in induced lesions, the contrast agent persisted longer in endometriotic than control tissues, thus enhancing the MRI signal intensity. DCE-MRI was repeated five weeks after lesion induction, and contrast enhancement was similar to that observed three weeks after endometriosis induction. The endothelial-cell marker CD31 and the pericyte marker α-smooth-muscle-actin (mature vessels) were detected with immunohistochemistry and confirmed that endometriotic lesions had significantly higher prevalence of new vessels (CD31 only positive) than the

[Clinical and magnetic resonance imaging characteristics of isolated congenital anosmia].

PubMed

Liu, Jian-feng; Wang, Jian; You, Hui; Ni, Dao-feng; Yang, Da-zhang

2010-05-25

To report a series of patients with isolated congenital anosmia and summarize their clinical and magnetic resonance imaging (MRI) characteristics. Twenty patients with isolated congenital anosmia were reviewed retrospectively. A thorough medical and chemosensory history, physical examination, nasal endoscopy, T&T olfactory testing, olfactory event-related potentials, sinonasal computed tomography scan and magnetic resonance image of olfactory pathway were performed in all patients. Neither ENT physical examination nor nasal endoscopy was remarkable. Subjective olfactory testing indicated all of them were of anosmia. No olfactory event-related potentials to maximal stimulus were obtained. Computed tomography scan was normal. MRI revealed the absence of olfactory bulbs and tracts in all cases. And hypoplasia or aplasia of olfactory sulcus was found in all cases. All the patients had normal sex hormone level. The diagnosis of isolated congenital anosmia is established on chief complaints, physical examination, olfactory testing and olfactory imaging. MRI of olfactory pathway is indispensable.

Magnetic resonance signal moment determination using the Earth's magnetic field.

PubMed

Fridjonsson, E O; Creber, S A; Vrouwenvelder, J S; Johns, M L

2015-03-01

We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth's magnetic field system. Copyright © 2015 Elsevier Inc. All rights reserved.

One-pot synthesis of magnetic nanoclusters enabling atherosclerosis-targeted magnetic resonance imaging.

PubMed

Kukreja, Aastha; Lim, Eun-Kyung; Kang, Byunghoon; Choi, Yuna; Lee, Taeksu; Suh, Jin-Suck; Huh, Yong-Min; Haam, Seungjoo

2014-01-01

In this study, dextran-encrusted magnetic nanoclusters (DMNCs) were synthesized using a one-pot solution phase method for detection of atherosclerosis by magnetic resonance imaging. Pyrenyl dextran was used as a surfactant because of its electron-stabilizing effect and its amphiphilic nature, rendering the DMNCs stable and water-dispersible. The DMNCs were 65.6±4.3 nm, had a narrow size distribution, and were superparamagnetic with a high magnetization value of 60.1 emu/g. Further, they showed biocompatibility and high cellular uptake efficiency, as indicated by a strong interaction between dextran and macrophages. In vivo magnetic resonance imaging demonstrated the ability of DMNCs to act as an efficient magnetic resonance imaging contrast agent capable of targeted detection of atherosclerosis. In view of these findings, it is concluded that DMNCs can be used as magnetic resonance imaging contrast agents to detect inflammatory disease.

Resonance of magnetization excited by voltage in magnetoelectric heterostructures

NASA Astrophysics Data System (ADS)

Yu, Guoliang; Zhang, Huaiwu; Li, Yuanxun; Li, Jie; Zhang, Dainan; Sun, Nian

2018-04-01

Manipulation of magnetization dynamics is critical for spin-based devices. Voltage driven magnetization resonance is promising for realizing low-power information processing systems. Here, we show through Finite Element Method (FEM) simulations that magnetization resonance in nanoscale magnetic elements can be generated by a radio frequency (rf) voltage via the converse magnetoelectric (ME) effect. The magnetization dynamics induced by voltage in a ME heterostructures is simulated by taking into account the magnetoelastic and piezoelectric coupling mechanisms among magnetization, strain and voltage. The frequency of the excited magnetization resonance is equal to the driving rf voltage frequency. The proposed voltage driven magnetization resonance excitation mechanism opens a way toward energy-efficient spin based device applications.

Hydatid cyst of the interventricular septum and contribution of magnetic resonance imaging.

PubMed

Kulan, K; Tuncer, C; Kulan, C; Serce, K; Goldeli, O; Irhan, S; Komsuoglu, B

1995-01-01

Cardiac echinococcosis has not been reported frequently. Because of the risk of potentially lethal complications, early diagnosis and definitive treatment are very important. We report a case of a cardiac echinococcal cyst in the interventricular septum. The cyst that caused angina and showed ischemic changes in electrocardiogram was diagnosed by two-dimensional echocardiography and magnetic resonance imaging and was treated surgically.

Plain radiography and magnetic resonance imaging diagnostics in osteoarthritis: validated staging and scoring.

PubMed

Guermazi, Ali; Hunter, David J; Roemer, Frank W

2009-02-01

Osteoarthritis is the most common joint disorder worldwide, and it has an enormous socioeconomic impact both in the United States and throughout the world. Conventional radiography is the simplest and least expensive imaging method for assessing osteoarthritis of the knee. Radiography is able to directly visualize osseous features of osteoarthritis, including marginal osteophytes, subchondral sclerosis, and subchondral cysts, and it is used in clinical practice to confirm the diagnosis of osteoarthritis and to monitor progression of the disease. However, the assessment of joint-space width provides only an indirect estimate of cartilage thickness and meniscal integrity. Magnetic resonance imaging, with its unique ability to examine the joint as a whole organ, holds great promise with regard to the rapid advancement of knowledge about the disease and the evaluation of novel treatment approaches. Magnetic resonance imaging has been applied widely in quantitative morphometric cartilage assessment, and compositional measures have been introduced that evaluate chondral integrity. In addition, magnetic resonance imaging-based validated semiquantitative whole-organ scoring methods have been applied for cross-sectional and longitudinal joint evaluation. This review describes currently applied radiographic and magnetic resonance imaging staging and scoring methods for the assessment of osteoarthritis of the knee and focuses on the strengths and weaknesses of the two modalities with regard to their use in clinical trials and epidemiologic studies.

[Achilles tendon xanthoma imaging on ultrasound and magnetic resonance imaging].

PubMed

Fernandes, Eloy de Ávila; Santos, Eduardo Henrique Sena; Tucunduva, Tatiana Cardoso de Mello; Ferrari, Antonio J L; Fernandes, Artur da Rocha Correa

2015-01-01

The Achilles tendon xanthoma is a rare disease and has a high association with primary hyperlipidemia. An early diagnosis is essential to start treatment and change the disease course. Imaging exams can enhance diagnosis. This study reports the case of a 60-year-old man having painless nodules on his elbows and Achilles tendons without typical gout crisis, followed in the microcrystalline disease clinic of Unifesp for diagnostic workup. Laboratory tests obtained showed dyslipidemia. The ultrasound (US) showed a diffuse Achilles tendon thickening with hypoechoic areas. Magnetic resonance imaging (MRI) showed a diffuse tendon thickening with intermediate signal areas, and a reticulate pattern within. Imaging studies showed relevant aspects to diagnose a xanthoma, thus helping in the differential diagnosis. Copyright © 2014 Elsevier Editora Ltda. All rights reserved.

Intraventricular mass lesions at magnetic resonance imaging: iconographic essay - part 1*

PubMed Central

de Castro, Felipe Damásio; Reis, Fabiano; Guerra, José Guilherme Giocondo

2014-01-01

The present essay is illustrated with magnetic resonance images obtained at the authors' institution over the past 15 years and discusses the main imaging findings of intraventricular tumor-like lesions (ependymoma, pilocytic astrocytoma, central neurocytoma, ganglioglioma, choroid plexus papilloma, primitive neuroectodermal tumors, meningioma, epidermoid tumor). Such lesions represent a subgroup of intracranial lesions with unique characteristics and some image patterns that may facilitate the differential diagnosis. PMID:25741075

Magnetic resonance imaging for the ophthalmologist: A primer

PubMed Central

Simha, Arathi; Irodi, Aparna; David, Sarada

2012-01-01

Magnetic resonance imaging (MRI) and computerized tomography (CT) have added a new dimension in the diagnosis and management of ocular and orbital diseases. Although CT is more widely used, MRI is the modality of choice in select conditions and can be complimentary to CT in certain situations. The diagnostic yield is best when the ophthalmologist and radiologist work together. Ophthalmologists should be able to interpret these complex imaging modalities as better clinical correlation is then possible. In this article, we attempt to describe the basic principles of MRI and its interpretation, avoiding confusing technical terms. PMID:22824600

Magnetic resonance imaging measurement of iron overload

PubMed Central

Wood, John C.

2010-01-01

Purpose of review To highlight recent advances in magnetic resonance imaging estimation of somatic iron overload. This review will discuss the need and principles of magnetic resonance imaging-based iron measurements, the validation of liver and cardiac iron measurements, and the key institutional requirements for implementation. Recent findings Magnetic resonance imaging assessment of liver and cardiac iron has achieved critical levels of availability, utility, and validity to serve as the primary endpoint of clinical trials. Calibration curves for the magnetic resonance imaging parameters R2 and R2* (or their reciprocals, T2 and T2*) have been developed for the liver and the heart. Interscanner variability for these techniques has proven to be on the order of 5–7%. Summary Magnetic resonance imaging assessment of tissue iron is becoming increasingly important in the management of transfusional iron load because it is noninvasive, relatively widely available and offers a window into presymptomatic organ dysfunction. The techniques are highly reproducible within and across machines and have been chemically validated in the liver and the heart. These techniques will become the standard of care as industry begins to support the acquisition and postprocessing software. PMID:17414205

[Prostate biopsy under magnetic resonance imaging guidance].

PubMed

Kuplevatskiy, V I; CherkashiN, M A; Roshchin, D A; Berezina, N A; Vorob'ev, N A

2016-01-01

Prostate cancer (PC) is one of the most important problems in modern oncology. According to statistical data, PC ranks second in the cancer morbidity structure in the Russian Federation and developed countries and its prevalence has been progressively increasing over the past decade. A need for early diagnosis and maximally accurate morphological verification of the diagnosis in difficult clinical cases (inconvenient tumor location for standard transrectal biopsy; gland scarring changes concurrent with prostatitis and hemorrhage; threshold values of prostate-specific antigen with unclear changes in its doubling per unit time; suspicion of biochemical recurrence or clinical tumor progression after special treatment) leads to revised diagnostic algorithms and clinically introduced new high-tech invasive diagnostic methods. This paper gives the first analysis of literature data on Russian practice using one of the new methods to verify prostate cancer (transrectal prostate cancer under magnetic resonance imaging (MRI) guidance). The have sought the 1995-2015 data in the MEDLINE and Pubmed.

Virtual special issue: Magnetic resonance at low fields

NASA Astrophysics Data System (ADS)

Blümich, Bernhard

2017-01-01

It appears to be a common understanding that low magnetic fields need to be avoided in magnetic resonance, as sensitivity and the frequency dispersion of the chemical shift increase with increasing field strength. But there many reasons to explore magnetic resonance at low fields. The instrumentation tends to be far less expensive than high-field equipment, magnets are smaller and lighter, internal gradients in heterogeneous media are smaller, conductive media and even metals become transparent at low frequencies to electromagnetic fields, and new physics and phenomena await to be discovered. On account of an increasing attention of the scientific community to magnetic resonance at low field, we have decided to launch JMR's Virtual Special Issue Series with this compilation about Low-Field Magnetic Resonance. This topic, for which we have chosen to focus on articles reporting measurements at fields lower than 2 T, is of widespread interest to our readership. We are therefore happy to offer to this constituency a selected outlook based on papers published during the last five years (volumes 214-270) in the pages of The Journal of Magnetic Resonance. A brief survey of the topics covered in this Virtual Special Issue follows.

Childhood temporal lobe epilepsy: correlation between electroencephalography and magnetic resonance spectroscopy: a case-control study.

PubMed

Azab, Seham Fa; Sherief, Laila M; Saleh, Safaa H; Elshafeiy, Mona M; Siam, Ahmed G; Elsaeed, Wafaa F; Arafa, Mohamed A; Bendary, Eman A; Sherbiny, Hanan S; Elbehedy, Rabab M; Aziz, Khalid A

2015-04-18

The diagnosis of epilepsy should be made as early as possible to give a child the best chance for treatment success and also to decrease complications such as learning difficulties and social and behavioral problems. In this study, we aimed to assess the ability of magnetic resonance spectroscopy (MRS) in detecting the lateralization side in patients with Temporal lobe epilepsy (TLE) in correlation with EEG and MRI findings. This was a case-control study including 40 patients diagnosed (clinically and by EEG) as having temporal lobe epilepsy aged 8 to 14 years (mean, 10.4 years) and 20 healthy children with comparable age and gender as the control group. All patients were subjected to clinical examination, interictal electroencephalography and magnetic resonance imaging (MRI). Proton magnetic resonance spectroscopic examination (MRS) was performed to the patients and the controls. According to the findings of electroencephalography, our patients were classified to three groups: Group 1 included 20 patients with unitemporal (lateralized) epileptic focus, group 2 included 12 patients with bitemporal (non-lateralized) epileptic focus and group 3 included 8 patients with normal electroencephalography. Magnetic resonance spectroscopy could lateralize the epileptic focus in 19 patients in group 1, nine patients in group2 and five patients in group 3 with overall lateralization of (82.5%), while electroencephalography was able to lateralize the focus in (50%) of patients and magnetic resonance imaging detected lateralization of mesial temporal sclerosis in (57.5%) of patients. Magnetic resonance spectroscopy is a promising tool in evaluating patients with epilepsy and offers increased sensitivity to detect temporal pathology that is not obvious on structural MRI imaging.

A modified method for locating parapharyngeal space neoplasms on magnetic resonance images: implications for differential diagnosis

PubMed Central

Liu, Xue-Wen; Wang, Ling; Li, Hui; Zhang, Rong; Geng, Zhi-Jun; Wang, De-Ling; Xie, Chuan-Miao

2014-01-01

The parapharyngeal space (PPS) is an inverted pyramid-shaped deep space in the head and neck region, and a variety of tumors, such as salivary gland tumors, neurogenic tumors, nasopharyngeal carcinomas with parapharyngeal invasion, and lymphomas, can be found in this space. The differential diagnosis of PPS tumors remains challenging for radiologists. This study aimed to develop and test a modified method for locating PPS tumors on magnetic resonance (MR) images to improve preoperative differential diagnosis. The new protocol divided the PPS into three compartments: a prestyloid compartment, the carotid sheath, and the areas outside the carotid sheath. PPS tumors were located in these compartments according to the displacements of the tensor veli palatini muscle and the styloid process, with or without blood vessel separations and medial pterygoid invasion. This protocol, as well as a more conventional protocol that is based on displacements of the internal carotid artery (ICA), was used to assess MR images captured from a series of 58 PPS tumors. The consequent distributions of PPS tumor locations determined by both methods were compared. Of all 58 tumors, our new method determined that 57 could be assigned to precise PPS compartments. Nearly all (13/14; 93%) tumors that were located in the pre-styloid compartment were salivary gland tumors. All 15 tumors within the carotid sheath were neurogenic tumors. The vast majority (18/20; 90%) of trans-spatial lesions were malignancies. However, according to the ICA-based method, 28 tumors were located in the pre-styloid compartment, and 24 were located in the post-styloid compartment, leaving 6 tumors that were difficult to locate. Lesions located in both the pre-styloid and the post-styloid compartments comprised various types of tumors. Compared with the conventional ICA-based method, our new method can help radiologists to narrow the differential diagnosis of PPS tumors to specific compartments. PMID:25104280

Reducing Field Distortion in Magnetic Resonance Imaging

NASA Technical Reports Server (NTRS)

Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

2010-01-01

A concept for a magnetic resonance imaging (MRI) system that would utilize a relatively weak magnetic field provides for several design features that differ significantly from the corresponding features of conventional MRI systems. Notable among these features are a magnetic-field configuration that reduces (relative to the conventional configuration) distortion and blurring of the image, the use of a superconducting quantum interference device (SQUID) magnetometer as the detector, and an imaging procedure suited for the unconventional field configuration and sensor. In a typical application of MRI, a radio-frequency pulse is used to excite precession of the magnetic moments of protons in an applied magnetic field, and the decaying precession is detected for a short time following the pulse. The precession occurs at a resonance frequency proportional to the strengths of the magnetic field and the proton magnetic moment. The magnetic field is configured to vary with position in a known way; hence, by virtue of the aforesaid proportionality, the resonance frequency varies with position in a known way. In other words, position is encoded as resonance frequency. MRI using magnetic fields weaker than those of conventional MRI offers several advantages, including cheaper and smaller equipment, greater compatibility with metallic objects, and higher image quality because of low susceptibility distortion and enhanced spin-lattice-relaxation- time contrast. SQUID MRI is being developed into a practical MRI method for applied magnetic flux densities of the order of only 100 T

Sedation of Pediatric Patients in Magnetic Resonance Imaging

DTIC Science & Technology

2000-01-03

f-U. 7. SEDATION OF PEDIATRIC PATIENTS IN MAGNETIC RESONANCE IMAGING Alesia D. Ricks APPROVED: ll^fll JohnJ>. McDonough,-CRNA, Ed.D., Chair...any copyrighted material in the thesis entitled: " Sedation of Pediatric Patients in Magnetic Resonance Imaging" beyond brief excerpts is with the...arise from such copyright violations. IV f SEDATION OF PEDIATRIC PATIENTS IN MAGNETIC RESONANCE IMAGING By CAPT ALESIA D. RICKS, RN, BSN, NQUSAF

[Quantitative experiment and analysis of gradient-induced eddy currents on magnetic resonance imaging].

PubMed

He, Wenjing; Zhu, Yuanzhong; Wang, Wenzhou; Zou, Kai; Zhang, Kai; He, Chao

2017-04-01

Pulsed magnetic field gradients generated by gradient coils are widely used in signal location in magnetic resonance imaging (MRI). However, gradient coils can also induce eddy currents in final magnetic field in the nearby conducting structures which lead to distortion and artifact in images, misguiding clinical diagnosis. We tried in our laboratory to measure the magnetic field of gradient-induced eddy current in 1.5 T superconducting magnetic resonance imaging device; and extracted key parameters including amplitude and time constant of exponential terms according to inductance-resistance series mathematical module. These parameters of both self-induced component and crossing component are useful to design digital filters to implement pulse pre-emphasize to reshape the waveform. A measure device that is a basement equipped with phantoms and receiving coils was designed and placed in the isocenter of the magnetic field. By applying testing sequence, contrast experiments were carried out in a superconducting magnet before and after eddy current compensation. Sets of one dimension signal were obtained as raw data to calculate gradient-induced eddy currents. Curve fitting by least squares method was also done to match inductance-resistance series module. The results also illustrated that pulse pre-emphasize measurement with digital filter was correct and effective in reducing eddy current effect. Pre-emphasize waveform was developed based on system function. The usefulness of pre-emphasize measurement in reducing eddy current was confirmed and the improvement was also presented. All these are valuable for reducing artifact in magnetic resonance imaging device.

Recent Advances in Cardiovascular Magnetic Resonance Techniques and Applications

PubMed Central

Salerno, Michael; Sharif, Behzad; Arheden, Håkan; Kumar, Andreas; Axel, Leon; Li, Debiao; Neubauer, Stefan

2018-01-01

Cardiovascular magnetic resonance imaging has become the gold standard for evaluating myocardial function, volumes, and scarring. Additionally, cardiovascular magnetic resonance imaging is unique in its comprehensive tissue characterization, including assessment of myocardial edema, myocardial siderosis, myocardial perfusion, and diffuse myocardial fibrosis. Cardiovascular magnetic resonance imaging has become an indispensable tool in the evaluation of congenital heart disease, heart failure, cardiac masses, pericardial disease, and coronary artery disease. This review will highlight some recent novel cardiovascular magnetic resonance imaging techniques, concepts, and applications. PMID:28611116

Low field magnetic resonance imaging

DOEpatents

Pines, Alexander; Sakellariou, Dimitrios; Meriles, Carlos A.; Trabesinger, Andreas H.

2010-07-13

A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

Tuning Coler Magnetic Current Apparatus with Magneto-Acoustic Resonance

NASA Astrophysics Data System (ADS)

Ludwig, Thorsten

An attempt was made to tune the Coler magnetic current apparatus with the magneto acoustic resonance of the magnetic rods. Measurements with a replica of the famous Coler "Magnetstromapparat" were conducted. In order to tune the acoustic, magnetic and electric resonance circuits of the Coler device the magneto-acoustic resonance was measured with a frequency scan through a function generator and a lock-in amplifier. The frequency generator was powering a driving coil, while the lock-in was connected to a pickup coil. Both coils were placed on a magnetic rod. Resonances were observed up to the 17th harmonic. The quality Q of the observed resonances was 270. To study the magneto-acoustic resonance in the time domain a pair of Permendur rods were employed. The magneto-acoustic resonances of the Permendur rods were observed with an oscilloscope. Spectra of the magneto acoustic resonance were measured for the Permendur rods and for a Coler replica magnet in the frequency range from 25 kHz to 380 kHz. The next step was to bring the resonances of the Permendur rods close together so that they overlap. The 10thharmonic was chosen because it was close to the 180 kHz that Hans Coler related to ferromagnetism. Further more magneto-acoustic coupling between the Permendur rods was studied. Finally the question was explored if Hans Coler converted vacuum fluctuations via magnetic and acoustic resonance into electricity. There is a strong connection between magnetism and quantum field zero point energy (ZPE). An outlook is given on next steps in the experiments to unveil the working mechanism of the Coler magnetic current apparatus.

Curcumin-conjugated magnetic nanoparticles for detecting amyloid plaques in Alzheimer's disease mice using magnetic resonance imaging (MRI).

PubMed

Cheng, Kwok Kin; Chan, Pui Shan; Fan, Shujuan; Kwan, Siu Ming; Yeung, King Lun; Wáng, Yì-Xiáng J; Chow, Albert Hee Lum; Wu, Ed X; Baum, Larry

2015-03-01

Diagnosis of Alzheimer's disease (AD) can be performed with the assistance of amyloid imaging. The current method relies on positron emission tomography (PET), which is expensive and exposes people to radiation, undesirable features for a population screening method. Magnetic resonance imaging (MRI) is cheaper and is not radioactive. Our approach uses magnetic nanoparticles (MNPs) made of superparamagnetic iron oxide (SPIO) conjugated with curcumin, a natural compound that specifically binds to amyloid plaques. Coating of curcumin-conjugated MNPs with polyethylene glycol-polylactic acid block copolymer and polyvinylpyrrolidone by antisolvent precipitation in a multi-inlet vortex mixer produces stable and biocompatible curcumin magnetic nanoparticles (Cur-MNPs) with mean diameter <100 nm. These nanoparticles were visualized by transmission electron microscopy and atomic force microscopy, and their structure and chemistry were further characterized by X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and Fourier transform infrared spectroscopy. Cur-MNPs exhibited no cytotoxicity in either Madin-Darby canine kidney (MDCK) or differentiated human neuroblastoma cells (SH-SY5Y). The Papp of Cur-MNPs was 1.03 × 10(-6) cm/s in an in vitro blood-brain barrier (BBB) model. Amyloid plaques could be visualized in ex vivo T2*-weighted magnetic resonance imaging (MRI) of Tg2576 mouse brains after injection of Cur-MNPs, and no plaques could be found in non-transgenic mice. Immunohistochemical examination of the mouse brains revealed that Cur-MNPs were co-localized with amyloid plaques. Thus, Cur-MNPs have the potential for non-invasive diagnosis of AD using MRI. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cardiovascular magnetic resonance in the evaluation of hypertrophic and infiltrative cardiomyopathies.

PubMed

O'Hanlon, Rory; Pennell, Dudley J

2009-07-01

There is often considerable phenotypic overlap in hypertrophic and infiltrative cardiomyopathies. This overlap creates difficulties, when using routine imaging modalities, in arriving at a conclusive diagnosis. Cardiovascular magnetic resonance (CMR) can make diagnosis easier and more certain. Used with gadolinium contrast agent for tissue characterization, CMR offers a superior field of view and temporal resolution, enabling clinicians to make more confident assessments of etiology. CMR may also be a useful modality for stratifying risk and monitoring treatment responses over time in patients with hypertrophic or infiltrative cardiomyopathies. This article highlights the role of CMR in the assessment and, if relevant, the risk stratification of hypertrophic and infiltrative cardiomyopathies.

Magnetic Resonance Fingerprinting

PubMed Central

Ma, Dan; Gulani, Vikas; Seiberlich, Nicole; Liu, Kecheng; Sunshine, Jeffrey L.; Duerk, Jeffrey L.; Griswold, Mark A.

2013-01-01

Summary Magnetic Resonance (MR) is an exceptionally powerful and versatile measurement technique. The basic structure of an MR experiment has remained nearly constant for almost 50 years. Here we introduce a novel paradigm, Magnetic Resonance Fingerprinting (MRF) that permits the non-invasive quantification of multiple important properties of a material or tissue simultaneously through a new approach to data acquisition, post-processing and visualization. MRF provides a new mechanism to quantitatively detect and analyze complex changes that can represent physical alterations of a substance or early indicators of disease. MRF can also be used to specifically identify the presence of a target material or tissue, which will increase the sensitivity, specificity, and speed of an MR study, and potentially lead to new diagnostic testing methodologies. When paired with an appropriate pattern recognition algorithm, MRF inherently suppresses measurement errors and thus can improve accuracy compared to previous approaches. PMID:23486058

Magnetic resonance imaging in local staging of endometrial carcinoma: diagnostic performance, pitfalls, and literature review.

PubMed

Zandrino, Franco; La Paglia, Ernesto; Musante, Francesco

2010-01-01

To assess the diagnostic accuracy of magnetic resonance imaging in local staging of endometrial carcinoma, and to review the results and pitfalls described in the literature. Thirty women with a histological diagnosis of endometrial carcinoma underwent magnetic resonance imaging. Unenhanced T2-weighted and dynamic contrast-enhanced Ti-weighted sequences were obtained. Hysterectomy and salpingo-oophorectomy was performed in all patients. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for the detection of deep myometrial and cervical infiltration. For deep myometrial infiltration T2-weighted sequences reached a sensitivity of 85%, specificity of 76%, PPV of 73%, NVP of 87%, and accuracy of 80%, while contrast-enhanced scans reached a sensitivity of 90%, specificity of 80%, PPV of 82%, NPV of 89%, and accuracy of 85%. For cervical infiltration T2-weighted sequences reached a sensitivity of 75%, specificity of 88%, PPV of 50%, NPV of 96%, and accuracy of 87%, while contrast-enhanced scans reached a sensitivity of 100%, specificity of 94%, PPV of 75%, NPV of 100%, and accuracy of 95%. Unenhanced and dynamic gadolinium-enhanced magnetic resonance allows accurate assessment of myometrial and cervical infiltration. Information provided by magnetic resonance imaging can define prognosis and management.

Magnetic Resonance with Squeezed Microwaves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bienfait, A.; Campagne-Ibarcq, P.; Kiilerich, A. H.

2017-10-17

Vacuum fluctuations of the electromagnetic field set a fundamental limit to the sensitivity of a variety of measurements, including magnetic resonance spectroscopy. We report the use of squeezed microwave fields, which are engineered quantum states of light for which fluctuations in one field quadrature are reduced below the vacuum level, to enhance the detection sensitivity of an ensemble of electronic spins at millikelvin temperatures. By shining a squeezed vacuum state on the input port of a microwave resonator containing the spins, we obtain a 1.2-dB noise reduction at the spectrometer output compared to the case of a vacuum input. Thismore » result constitutes a proof of principle of the application of quantum metrology to magnetic resonance spectroscopy.« less

Chemical Principles Revisited. Proton Magnetic Resonance Spectroscopy.

ERIC Educational Resources Information Center

McQuarrie, Donald A.

1988-01-01

Discusses how to interpret nuclear magnetic resonance (NMR) spectra and how to use them to determine molecular structures. This discussion is limited to spectra that are a result of observation of only the protons in a molecule. This type is called proton magnetic resonance (PMR) spectra. (CW)

Magnetic resonance imaging without field cycling at less than earth's magnetic field

NASA Astrophysics Data System (ADS)

Lee, Seong-Joo; Shim, Jeong Hyun; Kim, Kiwoong; Yu, Kwon Kyu; Hwang, Seong-min

2015-03-01

A strong pre-polarization field, usually tenths of a milli-tesla in magnitude, is used to increase the signal-to-noise ratio in ordinary superconducting quantum interference device-based nuclear magnetic resonance/magnetic resonance imaging experiments. Here, we introduce an experimental approach using two techniques to remove the need for the pre-polarization field. A dynamic nuclear polarization (DNP) technique enables us to measure an enhanced resonance signal. In combination with a π / 2 pulse to avoid the Bloch-Siegert effect in a micro-tesla field, we obtained an enhanced magnetic resonance image by using DNP technique with a 34.5 μT static external magnetic field without field cycling. In this approach, the problems of eddy current and flux trapping in the superconducting pickup coil, both due to the strong pre-polarization field, become negligible.

MRI and magnetic resonance angiography findings in patients with multiple sclerosis mimicked by stroke.

PubMed

Khedr, Abdullatif Al; Canaple, Sandrine; Monet, Pauline; Godefroy, Olivier; Bugnicourt, Jean-Marc

2013-08-01

We report a 45-year-old woman who presented with a first demyelinating event with abnormalities seen on both MRI and magnetic resonance angiography that were highly suggestive of acute ischemic stroke. This report highlights the problem of differential diagnosis of acute neurological symptoms in adult subjects. Copyright © 2012 Elsevier Ltd. All rights reserved.

Magnetic resonance dispersion imaging for localization of angiogenesis and cancer growth.

PubMed

Mischi, Massimo; Turco, Simona; Lavini, Cristina; Kompatsiari, Kyveli; de la Rosette, Jean J M C H; Breeuwer, Marcel; Wijkstra, Hessel

2014-08-01

Cancer angiogenesis can be imaged by using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Pharmacokinetic modeling can be used to assess vascular perfusion and permeability, but the assessment of angiogenic changes in the microvascular architecture remains challenging. This article presents 2 models enabling the characterization of the microvascular architecture by DCE-MRI. The microvascular architecture is reflected in the dispersion coefficient according to the convective dispersion equation. A solution of this equation, combined with the Tofts model, permits defining a dispersion model for magnetic resonance imaging. A reduced dispersion model is also presented. The proposed models were evaluated for prostate cancer diagnosis. Dynamic contrast-enhanced magnetic resonance imaging was performed, and concentration-time curves were calculated in each voxel. The simultaneous generation of parametric maps related to permeability and dispersion was obtained through model fitting. A preliminary validation was carried out through comparison with the histology in 15 patients referred for radical prostatectomy. Cancer localization was accurate with both dispersion models, with an area under the receiver operating characteristic curve greater than 0.8. None of the compared parameters, aimed at assessing vascular permeability and perfusion, showed better results. A new DCE-MRI method is proposed to characterize the microvascular architecture through the assessment of intravascular dispersion, without the need for separate arterial-input-function estimation. The results are promising and encourage further research.

Magnetic Resonance Imaging (MRI): Lumbar Spine (For Parents)

MedlinePlus

... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Lumbar Spine KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Lumbar Spine What's in this article? What ...

Functional Magnetic Resonance Imaging and Pediatric Anxiety

ERIC Educational Resources Information Center

Pine, Daniel S.; Guyer, Amanda E.; Leibenluft, Ellen; Peterson, Bradley S.; Gerber, Andrew

2008-01-01

The use of functional magnetic resonance imaging in investigating pediatric anxiety disorders is studied. Functional magnetic resonance imaging can be utilized in demonstrating parallels between the neural architecture of difference in anxiety of humans and the neural architecture of attention-orienting behavior in nonhuman primates or rodents.…

Magnetic Field Gradient Calibration as an Experiment to Illustrate Magnetic Resonance Imaging

ERIC Educational Resources Information Center

Seedhouse, Steven J.; Hoffmann, Markus M.

2008-01-01

A nuclear magnetic resonance (NMR) spectroscopy experiment for the undergraduate physical chemistry laboratory is described that encompasses both qualitative and quantitative pedagogical goals. Qualitatively, the experiment illustrates how images are obtained in magnetic resonance imaging (MRI). Quantitatively, students experience the…

Magnetic resonance enterography in pediatric celiac disease.

PubMed

Koc, Gonca; Doganay, Selim; Sevinc, Eylem; Deniz, Kemal; Chavhan, Govind; Gorkem, Sureyya B; Karacabey, Neslihan; Dogan, Mehmet S; Coskun, Abdulhakim; Aslan, Duran

To assess if magnetic resonance enterography is capable of showing evidence/extent of disease in pediatric patients with biopsy-proven celiac disease by comparing with a control group, and to correlate the magnetic resonance enterography findings with anti-endomysial antibody level, which is an indicator of gluten-free dietary compliance. Thirty-one pediatric patients (mean age 11.7±3.1 years) with biopsy-proven celiac disease and 40 pediatric patients as a control group were recruited in the study. The magnetic resonance enterography images of both patients with celiac disease and those of the control group were evaluated by two pediatric radiologists in a blinded manner for the mucosal pattern, presence of wall thickening, luminal distention of the small bowel, and extra-intestinal findings. Patient charts were reviewed to note clinical features and laboratory findings. The histopathologic review of the duodenal biopsies was re-conducted. The mean duration of the disease was 5.6±1.8 years (range: 3-7.2 years). In 24 (77%) of the patients, anti-endomysial antibody levels were elevated (mean 119.2±66.6RU/mL). Magnetic resonance enterography revealed normal fold pattern in all the patients. Ten (32%) patients had enlarged mesenteric lymph nodes. Although a majority of the patients had elevated anti-endomysial antibody levels indicating poor dietary compliance, magnetic resonance enterography did not show any mucosal abnormality associated with the inability of magnetic resonance enterography to detect mild/early changes of celiac disease in children. Therefore, it may not be useful for the follow-up of pediatric celiac disease. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Accuracy of magnetic resonance in deeply infiltrating endometriosis: a systematic review and meta-analysis.

PubMed

Medeiros, Lídia Rossi; Rosa, Maria Inês; Silva, Bruno Rosa; Reis, Maria Eduarda; Simon, Carla Sasso; Dondossola, Eduardo Ronconi; da Cunha Filho, João Sabino

2015-03-01

To estimate the accuracy of pelvic magnetic resonance imaging (MRI) in the diagnosis of deeply infiltrating endometriosis (DIE). A comprehensive search of the Medline, Pubmed, Lilacs, Scopus, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Biomed Central, and ISI Web of Science databases was conducted from January 1990 to December 2013. The medical subject headings (MeSHs) and text words "deep endometriosis", "deeply infiltrating endometriosis", "DIE", "magnetic resonance", and "MRI" were searched. Studies that compared the parameters of pelvic MRIs with those of paraffin-embedded sections for the diagnosis of DIE were included. Twenty studies were analyzed, which included 1,819 women. Pooled sensitivity and specificity were calculated across eight subgroups: for all sites, these were 0.83 and 0.90, respectively; for the bladder, 0.64 and 0.98, respectively; for the intestine, 0.84 and 0.97, respectively; for the pouch of Douglas, 0.89 and 0.94, respectively; for the rectosigmoid, 0.83 and 0.88, respectively; for the rectovaginal, 0.77 and 0.95, respectively; for the uterosacral ligaments, 0.85 and 0.80, respectively; and for the vagina and the posterior vaginal fornix, 0.82 and 0.82, respectively. In summary, pelvic MRI is a useful preoperative test for predicting the diagnosis of multiple sites of deep infiltrating endometriosis.

Magnetic elliptical polarization of Schumann resonances

NASA Technical Reports Server (NTRS)

Sentman, D. D.

1987-01-01

Measurements of orthogonal, horizontal components of the magnetic field in the ELF range obtained during September 1985 show that the Schumann resonance eigenfrequencies determined separately for the north-south and east-west magnetic components differ by as much as 0.5 Hz, suggesting that the underlying magnetic signal is not linearly polarized at such times. The high degree of magnetic ellipticity found suggests that the side multiplets of the Schumann resonances corresponding to azimuthally inhomogeneous normal modes are strongly excited in the highly asymmetric earth-ionosphere cavity. The dominant sense of polarization over the measurement passband is found to be right-handed during local daylight hours, and to be left-handed during local nighttime hours.

Plasmon-Induced Magnetic Resonance Enhanced Raman Spectroscopy.

PubMed

Chen, Shu; Zhang, Yuejiao; Shih, Tien-Mo; Yang, Weimin; Hu, Shu; Hu, Xiaoyan; Li, Jianfeng; Ren, Bin; Mao, Bingwei; Yang, Zhilin; Tian, Zhongqun

2018-04-11

Plasmon-induced magnetic resonance has shown great potentials in optical metamaterials, chemical (bio)-sensing, and surface-enhanced spectroscopies. Here, we have theoretically and experimentally revealed (1) a correspondence of the strongest near-field response to the far-field scattering valley and (2) a significant improvement in Raman signals of probing molecules by the plasmon-induced magnetic resonance. These revelations are accomplished by designing a simple and practical metallic nanoparticle-film plasmonic system that generates magnetic resonances at visible-near-infrared frequencies. Our work may provide new insights for understanding the enhancement mechanism of various plasmon-enhanced spectroscopies and also helps further explore light-matter interactions at the nanoscale.

Magnetic field shift due to mechanical vibration in functional magnetic resonance imaging.

PubMed

Foerster, Bernd U; Tomasi, Dardo; Caparelli, Elisabeth C

2005-11-01

Mechanical vibrations of the gradient coil system during readout in echo-planar imaging (EPI) can increase the temperature of the gradient system and alter the magnetic field distribution during functional magnetic resonance imaging (fMRI). This effect is enhanced by resonant modes of vibrations and results in apparent motion along the phase encoding direction in fMRI studies. The magnetic field drift was quantified during EPI by monitoring the resonance frequency interleaved with the EPI acquisition, and a novel method is proposed to correct the apparent motion. The knowledge on the frequency drift over time was used to correct the phase of the k-space EPI dataset. Since the resonance frequency changes very slowly over time, two measurements of the resonance frequency, immediately before and after the EPI acquisition, are sufficient to remove the field drift effects from fMRI time series. The frequency drift correction method was tested "in vivo" and compared to the standard image realignment method. The proposed method efficiently corrects spurious motion due to magnetic field drifts during fMRI. (c) 2005 Wiley-Liss, Inc.

The Utility of Cardiac Magnetic Resonance Imaging in the Diagnosis of Cardiac Sarcoidosis.

PubMed

Stanton, Kelly M; Ganigara, Madhusudan; Corte, Peter; Celermajer, David S; McGuire, Mark A; Torzillo, Paul J; Corte, Tamera J; Puranik, Rajesh

2017-11-01

Autopsy reports suggest that cardiac sarcoidosis occurs in 20 to 25% of patients with pulmonary sarcoidosis, yet the clinical ante-mortem diagnosis is made in only 5% of cases. Current diagnostic algorithms are complex and lack sensitivity. Cardiac Magnetic Resonance imaging (CMR) provides an opportunity to detect myocardial involvement in sarcoidosis. The aim of this study is to determine the prevalence and clinical significance of late gadolinium enhancement (LGE) on CMR in patients with sarcoidosis. Consecutive patients with biopsy-proven sarcoidosis undergoing CMR were retrospectively evaluated for cardiac sarcoidosis. Medical records were correlated with CMR. Forty-six patients were evaluated. Late gadolinium enhancement was present in 22%, indicating myocardial involvement, and 70% had corresponding hyper-intense T2 signal indicating active inflammation. Late gadolinium enhancement was 18%+/-9.7% of overall left ventricular (LV) mass and most commonly located in the basal to mid septum. There was no association between LGE and cardiovascular symptoms or pulmonary stage. Eighty per cent of patients with LGE did not fulfill conventional diagnostic criteria for cardiac sarcoidosis. However, LGE was associated with clinically significant arrhythmia (p<0.01) and a lower LVEF (p=0.04). Using CMR, we identified a higher prevalence of cardiac sarcoidosis than previously reported clinical studies, a prevalence which is more consistent with autopsy data. The presence of LGE was highly correlated with clinically significant arrhythmias and lower LVEF. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). All rights reserved.

Computed tomography and magnetic resonance imaging findings of intraorbital granular cell tumor (Abrikossoff's tumor): a case report.

PubMed

Yuan, Wei-Hsin; Lin, Tai-Chi; Lirng, Jiing-Feng; Guo, Wan-You; Chang, Fu-Pang; Ho, Donald Ming-Tak

2016-05-13

Granular cell tumors are rare neoplasms which can occur in any part of the body. Granular cell tumors of the orbit account for only 3 % of all granular cell tumor cases. Computed tomography and magnetic resonance imaging of the orbit have proven useful for diagnosing orbital tumors. However, the rarity of intraorbital granular cell tumors poses a significant diagnostic challenge for both clinicians and radiologists. We report a case of a 37-year-old Chinese woman with a rare intraocular granular cell tumor of her right eye presenting with diplopia, proptosis, and restriction of ocular movement. Preoperative orbital computed tomography and magnetic resonance imaging with contrast enhancement revealed an enhancing solid, ovoid, well-demarcated, retrobulbar nodule. In addition, magnetic resonance imaging features included an intraorbital tumor which was isointense relative to gray matter on T1-weighted imaging and hypointense on T2-weighted imaging. No diffusion restriction of water was noted on either axial diffusion-weighted images or apparent diffusion coefficient maps. Both computed tomography and magnetic resonance imaging features suggested an intraorbital hemangioma. However, postoperative pathology (together with immunohistochemistry) identified an intraorbital granular cell tumor. When intraorbital T2 hypointensity and free diffusion of water are observed on magnetic resonance imaging, a granular cell tumor should be included in the differential diagnosis of an intraocular tumor.

[Is magnetic resonance imaging absolutely necessary for musculotendinous disease?].

PubMed

García González, Pedro; Meana Morís, Ana R

2016-01-01

Disorders of the musculoskeletal system are very prevalent in our society, especially those involving muscles and tendons, above all related to sports and work. These conditions are normally diagnosed and treated according to their clinical symptoms and signs, but a precise diagnosis is often necessary. The most widely used techniques for diagnosing these conditions are ultrasonography and magnetic resonance imaging. In this article, we propose ultrasonography as the technique of choice for diagnosing the most prevalent musculotendinous diseases, because it is accurate, versatile, dynamic, and effective. Copyright © 2015 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

Psychological reactions in women undergoing fetal magnetic resonance imaging.

PubMed

Leithner, Katharina; Pörnbacher, Susanne; Assem-Hilger, Eva; Krampl, Elisabeth; Ponocny-Seliger, Elisabeth; Prayer, Daniela

2008-02-01

To investigate women's psychological reactions when undergoing fetal magnetic resonance imaging (MRI), and to estimate whether certain groups, based on clinical and sociodemographic variables, differ in their subjective experiences with fetal MRI and in their anxiety levels related to the scanning procedure. This study is a prospective cohort investigation of 62 women before and immediately after fetal MRI. Anxiety levels and subjective experiences were measured by questionnaires. Groups based on clinical and sociodemographic variables were compared with regard to anxiety levels and to the scores on the Prescan and Postscan Imaging Distress Questionnaire. Anxiety scores before fetal MRI were 8.8 points higher than those of the female, nonclinical, norm population (P<.001). The severity of the referral diagnosis showed a linearly increasing effect on anxiety level before MRI (weighted linear term: F1,59=5.325, P=.025). Magnetic resonance imaging was experienced as unpleasant by 33.9% (95% confidence interval [CI] 21.2-46.6%) and as hardly bearable by 4.8% (95% CI 0-17.5%) of the women. Physical restraint (49.9%, 95% CI 37.4-62.4%), noise level (53.2%, 95% CI 40.7-65.7%), anxiety for the infant (53.2%, 95% CI 40.7-65.7%), and the duration of the examination (51.6%, 95% CI 39.1-64.1%) were major distressing factors. Women who undergo fetal magnetic resonance imaging experience considerable distress, especially those with poor fetal prognoses. Ongoing technical developments, such as a reduction of noise, shortening the duration of the MRI, and a more comfortable position in open MRI machines, may have the potential to improve the subjective experiences of women during fetal MRI. III.

Magnetic Resonance Spectroscopy: An Objective Modality to Identify the Pathology of Breast Neoplasms

DTIC Science & Technology

1999-05-01

Zealand Journal or Surgery Appendix IV: Attached Manuscript published in Life Sciences Appendix V: Attached Figures 1-13 Appendix VI: Attached Tables 1... early diagnosis and effective management. The triage of mammography, clinical examination and fine needle aspiration biopsy is currently used to...identify early breast cancers. Magnetic resonance imaging (MRI) has now been added to select women with breast abnormalities requiring biopsy. However

Magnetic Resonance Imaging of Surgical Implants Made from Weak Magnetic Materials

NASA Astrophysics Data System (ADS)

Gogola, D.; Krafčík, A.; Štrbák, O.; Frollo, I.

2013-08-01

Materials with high magnetic susceptibility cause local inhomogeneities in the main field of the magnetic resonance (MR) tomograph. These inhomogeneities lead to loss of phase coherence, and thus to a rapid loss of signal in the image. In our research we investigated inhomogeneous field of magnetic implants such as magnetic fibers, designed for inner suture during surgery. The magnetic field inhomogeneities were studied at low magnetic planar phantom, which was made from four thin strips of magnetic tape, arranged grid-wise. We optimized the properties of imaging sequences with the aim to find the best setup for magnetic fiber visualization. These fibers can be potentially exploited in surgery for internal stitches. Stitches can be visualized by the magnetic resonance imaging (MRI) method after surgery. This study shows that the imaging of magnetic implants is possible by using the low field MRI systems, without the use of complicated post processing techniques (e.g., IDEAL).

Cardiac Magnetic Resonance and Computed Tomography in Hypertrophic Cardiomyopathy: an Update

PubMed Central

de Oliveira, Diogo Costa Leandro; Assunção, Fernanda Boldrini; dos Santos, Alair Agusto Sarmet Moreira Damas; Nacif, Marcelo Souto

2016-01-01

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease and represents the main cause of sudden death in young patients. Cardiac magnetic resonance (CMR) and cardiac computed tomography (CCT) are noninvasive imaging methods with high sensitivity and specificity, useful for the establishment of diagnosis and prognosis of HCM, and for the screening of patients with subclinical phenotypes. The improvement of image analysis by CMR and CCT offers the potential to promote interventions aiming at stopping the natural course of the disease. This study aims to describe the role of RCM and CCT in the diagnosis and prognosis of HCM, and how these methods can be used in the management of these patients. PMID:27305111

The cranial nuchal bursa: anatomy, ultrasonography, magnetic resonance imaging and endoscopic approach.

PubMed

Abuja, G A; García-López, J M; Manso-Díaz, G; Spoormakers, T J P; Taeymans, O

2014-11-01

Although an uncommon condition, cranial nuchal bursitis can affect the performance of the equine athlete. The anatomy is not well described and there are no reports of diagnostic imaging for endoscopic approaches. To describe the anatomy, ultrasonographic and magnetic resonance features of and endoscopic approach to the cranial nuchal bursa in horses. Experimental cadaver study. Four cranial nuchal bursae were dissected, 4 specimens were frozen to prepare anatomical sections and 2 were injected with latex to document surface landmarks and topographical anatomy and to identify the possible sites for endoscopic access. Six cadaveric specimens were used to describe the ultrasonographic and magnetic resonance features of the cranial nuchal bursa before and after intrabursal injection. Sixteen cadaver specimens were evaluated with a rigid arthroscope and gross dissection to determine the endoscopic appearance of the bursa. The cranial nuchal bursa could be identified consistently in all cadavers, using ultrasonographic and magnetic resonance on both pre- and post injection specimens. Cranial and caudal endoscopic approaches and instrument portals were developed for the cranial nuchal bursa. Using either approach, the entire extent of the bursa could be evaluated, but separate approaches for left and right compartments of the bursa were needed owing to the lack of manoeuvrability when examining the contralateral compartment. The cranial nuchal bursa can be identified on ultrasonographic and magnetic resonance images. An endoscopic approach to the cranial nuchal bursa is clinically feasible and offered an easy, repeatable entry into the cranial nuchal bursa, which allowed adequate observation of the structures within the bursa. This may be of help for diagnosis and treatment of conditions affecting the cranial nuchal bursa in horses. © 2014 EVJ Ltd.

F-18 fluoride positron emission tomography/computed tomography in the diagnosis of avascular necrosis of the femoral head: Comparison with magnetic resonance imaging

PubMed Central

Gayana, Shankaramurthy; Bhattacharya, Anish; Sen, Ramesh Kumar; Singh, Paramjeet; Prakash, Mahesh; Mittal, Bhagwant Rai

2016-01-01

Objective: Femoral head avascular necrosis (FHAVN) is one of the increasingly common causes of musculoskeletal disability and poses a major diagnostic and therapeutic challenge. Although radiography, scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI) have been widely used in the diagnosis of FHAVN, positron emission tomography (PET) has recently been evaluated to assess vascularity of the femoral head. In this study, the authors compared F-18 fluoride PET/CT with MRI in the initial diagnosis of FHAVN. Patients and Methods: We prospectively studied 51 consecutive patients with a high clinical suspicion of FHAVN. All patients underwent MRI and F-18 fluoride PET/CT, the time interval between the two scans being 4–10 (mean 8) days. Two nuclear medicine physicians blinded to the MRI report read the PET/CT scans. Clinical assessment was also done. Final diagnoses were made by surgical pathology or clinical and radiologic follow-up. Results: A final diagnosis of avascular necrosis (AVN) was made in 40 patients. MRI was 96.5% sensitive, 100% specific, and 98.03% accurate while PET/CT was 100% sensitive, specific, and accurate in diagnosing FHAVN. The agreement between the two imaging modalities for the diagnosis of AVN was 96.07%. Conclusion: F-18 fluoride PET/CT showed good agreement with MRI in the initial diagnosis of FHAVN and can be better than MRI in detecting early disease. PMID:26917886

Magnetic resonance imaging of glenohumeral joint instability.

PubMed

Steinbach, Lynne S

2005-03-01

Shoulder instability is common, especially anterior subluxation and dislocation. The sequelae are well seen on magnetic resonance imaging and include tears of the labrum, glenohumeral ligaments, capsule, tendons, and muscles. This article seeks to discuss and illustrate common pitfalls and lesions associated with instability. Anatomic and technical considerations, including the use of magnetic resonance arthrography, are also addressed.

Thoracic magnetic resonance imaging: pulmonary thromboembolism.

PubMed

Fink, Christian; Henzler, Thomas; Shirinova, Aysel; Apfaltrer, Paul; Wasser, Klaus

2013-05-01

Ongoing technical developments have substantially improved the potential of magnetic resonance imaging (MRI) in the assessment of the pulmonary circulation. These developments includes improved magnet and hardware design, new k-space sampling techniques (ie, parallel imaging), and alternative contrast materials. With these techniques, not only can pulmonary vessels be visualized by MR angiography with high spatial resolution but also the perfusion of the lungs and its changes in relation to pulmonary thromboembolism (PE) can be assessed. Considering venous thromboembolism as a systemic disease, MR venography might be added for the diagnosis of underlying deep venous thrombosis. A unique advantage of MRI over other imaging tests is its potential to evaluate changes in cardiac function as a result of obstruction of the pulmonary circulation, which may have a significant impact on patient monitoring and treatment. Finally, MRI does not involve radiation, which is advantageous, especially in young patients. Over the years, a number of studies have shown promising results not only for MR angiography but also for MRI of lung perfusion and for MR venography. This review article summarizes and discusses the current evidence on pulmonary MRI for patients with suspected PE.

Magnetic resonance imaging of cartilage repair.

PubMed

Potter, Hollis G; Chong, Le Roy; Sneag, Darryl B

2008-12-01

Magnetic resonance imaging is an important noninvasive modality in characterizing cartilage morphology, biochemistry, and function. It serves as a valuable objective outcome measure in diagnosing pathology at the time of initial injury, guiding surgical planning, and evaluating postsurgical repair. This article reviews the current literature addressing the recent advances in qualitative and quantitative magnetic resonance imaging techniques in the preoperative setting, and in patients who have undergone cartilage repair techniques such as microfracture, autologous cartilage transplantation, or osteochondral transplantation.

Accuracy of diagnoses from magnetic resonance imaging of the knee. A multi-center analysis of one thousand and fourteen patients.

PubMed

Fischer, S P; Fox, J M; Del Pizzo, W; Friedman, M J; Snyder, S J; Ferkel, R D

1991-01-01

Magnetic resonance images of the knee were made for 1014 patients, and the diagnosis was subsequently confirmed arthroscopically. The accuracy of the diagnoses from the imaging was 89 per cent for the medial meniscus, 88 per cent for the lateral meniscus, 93 per cent for the anterior cruciate ligament, and 99 per cent for the posterior cruciate ligament. The magnetic resonance examinations were done at several centers, and the results varied substantially among centers. The accuracy ranged from 64 to 95 per cent for the medial meniscus, from 83 to 94 per cent for the lateral meniscus, and from 78 to 97 per cent for the anterior cruciate ligament. The results from different magnetic-resonance units were also compared, and the findings suggested increased accuracy for the units that had a stronger magnetic field. Of the menisci for which the magnetic resonance signal was reported to be Grade II (a linear intrameniscal signal not extending to the superior or inferior meniscal surface), 17 per cent were found to be torn at arthroscopy.

Magnetic resonance imaging of breast implants.

PubMed

Shah, Mala; Tanna, Neil; Margolies, Laurie

2014-12-01

Silicone breast implants have significantly evolved since their introduction half a century ago, yet implant rupture remains a common and expected complication, especially in patients with earlier-generation implants. Magnetic resonance imaging is the primary modality for assessing the integrity of silicone implants and has excellent sensitivity and specificity, and the Food and Drug Administration currently recommends periodic magnetic resonance imaging screening for silent silicone breast implant rupture. Familiarity with the types of silicone implants and potential complications is essential for the radiologist. Signs of intracapsular rupture include the noose, droplet, subcapsular line, and linguine signs. Signs of extracapsular rupture include herniation of silicone with a capsular defect and extruded silicone material. Specific sequences including water and silicone suppression are essential for distinguishing rupture from other pathologies and artifacts. Magnetic resonance imaging provides valuable information about the integrity of silicone implants and associated complications.

Accuracy of magnetic resonance based susceptibility measurements

NASA Astrophysics Data System (ADS)

Erdevig, Hannah E.; Russek, Stephen E.; Carnicka, Slavka; Stupic, Karl F.; Keenan, Kathryn E.

2017-05-01

Magnetic Resonance Imaging (MRI) is increasingly used to map the magnetic susceptibility of tissue to identify cerebral microbleeds associated with traumatic brain injury and pathological iron deposits associated with neurodegenerative diseases such as Parkinson's and Alzheimer's disease. Accurate measurements of susceptibility are important for determining oxygen and iron content in blood vessels and brain tissue for use in noninvasive clinical diagnosis and treatment assessments. Induced magnetic fields with amplitude on the order of 100 nT, can be detected using MRI phase images. The induced field distributions can then be inverted to obtain quantitative susceptibility maps. The focus of this research was to determine the accuracy of MRI-based susceptibility measurements using simple phantom geometries and to compare the susceptibility measurements with magnetometry measurements where SI-traceable standards are available. The susceptibilities of paramagnetic salt solutions in cylindrical containers were measured as a function of orientation relative to the static MRI field. The observed induced fields as a function of orientation of the cylinder were in good agreement with simple models. The MRI susceptibility measurements were compared with SQUID magnetometry using NIST-traceable standards. MRI can accurately measure relative magnetic susceptibilities while SQUID magnetometry measures absolute magnetic susceptibility. Given the accuracy of moment measurements of tissue mimicking samples, and the need to look at small differences in tissue properties, the use of existing NIST standard reference materials to calibrate MRI reference structures is problematic and better reference materials are required.

Magnetic resonance imaging and magnetic resonance spectroscopy for detection of early Alzheimer's disease.

PubMed

Westman, Eric; Wahlund, Lars-Olof; Foy, Catherine; Poppe, Michaela; Cooper, Allison; Murphy, Declan; Spenger, Christian; Lovestone, Simon; Simmons, Andrew

2011-01-01

Alzheimer's disease is the most common form of neurodegenerative disorder and early detection is of great importance if new therapies are to be effectively administered. We have investigated whether the discrimination between early Alzheimer's disease (AD) and elderly healthy control subjects can be improved by adding magnetic resonance spectroscopy (MRS) measures to magnetic resonance imaging (MRI) measures. In this study 30 AD patients and 36 control subjects were included. High resolution T1-weighted axial magnetic resonance images were obtained from each subject. Automated regional volume segmentation and cortical thickness measures were determined for the images. 1H MRS was acquired from the hippocampus and LCModel was used for metabolic quantification. Altogether, this yielded 58 different volumetric, cortical thickness and metabolite ratio variables which were used for multivariate analysis to distinguish between subjects with AD and Healthy controls. Combining MRI and MRS measures resulted in a sensitivity of 97% and a specificity of 94% compared to using MRI or MRS measures alone (sensitivity: 87%, 76%, specificity: 86%, 83% respectively). Adding the MRS measures to the MRI measures more than doubled the positive likelihood ratio from 6 to 17. Adding MRS measures to a multivariate analysis of MRI measures resulted in significantly better classification than using MRI measures alone. The method shows strong potential for discriminating between Alzheimer's disease and controls.

Controlling interactions between highly magnetic atoms with Feshbach resonances.

PubMed

Kotochigova, Svetlana

2014-09-01

This paper reviews current experimental and theoretical progress in the study of dipolar quantum gases of ground and meta-stable atoms with a large magnetic moment. We emphasize the anisotropic nature of Feshbach resonances due to coupling to fast-rotating resonant molecular states in ultracold s-wave collisions between magnetic atoms in external magnetic fields. The dramatic differences in the distribution of resonances of magnetic (7)S3 chromium and magnetic lanthanide atoms with a submerged 4f shell and non-zero electron angular momentum is analyzed. We focus on dysprosium and erbium as important experimental advances have been recently made to cool and create quantum-degenerate gases for these atoms. Finally, we describe progress in locating resonances in collisions of meta-stable magnetic atoms in electronic P-states with ground-state atoms, where an interplay between collisional anisotropies and spin-orbit coupling exists.

Recent advances in magnetic nanoparticle-based molecular probes for hepatocellular carcinoma diagnosis and therapy.

PubMed

Zhang, Qi; Wang, Sudan; Qiao, Ruirui; Whittaker, Michael; Quinn, John; Davis, Thomas P; Li, Hongjun

2018-05-15

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, leading to the second most likely cause of cancer-related deaths. Medical imaging is crucial in clinic for HCC screening and diagnosis. Due to the relatively high special resolution and excellent sensitivity, magnetic resonance imaging (MRI) by using magnetic nanoparticle-based contrast agents has been used so far in HCC imaging and staging, demonstrating great potential and promising in vivo applications. This review focuses on the use of different magnetic nanoparticles for construction of HCC nanoprobes for MR imaging and theranostic purpose. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Comparison of O-(2-18F-Fluoroethyl)-L-Tyrosine Positron Emission Tomography and Perfusion-Weighted Magnetic Resonance Imaging in the Diagnosis of Patients with Progressive and Recurrent Glioma: A Hybrid Positron Emission Tomography/Magnetic Resonance Study.

PubMed

Verger, Antoine; Filss, Christian P; Lohmann, Philipp; Stoffels, Gabriele; Sabel, Michael; Wittsack, Hans-J; Kops, Elena Rota; Galldiks, Norbert; Fink, Gereon R; Shah, Nadim J; Langen, Karl-Josef

2018-05-01

To compare the diagnostic performance of O-(2- 18 F-fluoroethyl)-L-tyrosine ( 18 F-FET) positron emission tomography (PET) and perfusion-weighted magnetic resonance imaging (PWI) for the diagnosis of progressive or recurrent glioma. Thirty-two pretreated gliomas (25 progressive or recurrent tumors, 7 treatment-related changes) were investigated with 18 F-FET PET and PWI via a hybrid PET/magnetic resonance scanner. Volumes of interest with a diameter of 16 mm were centered on the maximum of abnormality in the tumor area in PET and PWI maps (relative cerebral blood volume, relative cerebral blood flow, mean transit time) and the contralateral unaffected hemisphere. Mean and maximum tumor-to-brain ratios as well as dynamic data for 18 F-FET uptake were calculated. Diagnostic accuracies were evaluated by receiver operating characteristic analyses, calculating the area under the curve. 18 F-FET PET showed a significant greater sensitivity to detect abnormalities in pretreated gliomas than PWI (76% vs. 52%, P = 0.03). The maximum tumor-to-brain ratio of 18 F-FET PET was the only parameter that discriminated treatment-related changes from progressive or recurrent gliomas (area under the curve, 0.78; P = 0.03, best cut-off 2.61; sensitivity 80%, specificity 86%, accuracy 81%). Among patients with signal abnormality in both modalities, 75% revealed spatially incongruent local hot spots. This pilot study suggests that 18 F-FET PET is superior to PWI to diagnose progressive or recurrent glioma. Copyright © 2018 Elsevier Inc. All rights reserved.

Prenatal diagnosis of bilateral anophthalmia by 3D "reverse face" view ultrasound and magnetic resonance imaging.

PubMed

Araujo Júnior, Edward; Kawanami, Tatiana Emy; Nardozza, Luciano Marcondes Machado; Milani, Hérbene José Figuinha; Oliveira, Patrícia Soares; Moron, Antonio Fernandes

2012-12-01

Primary anophthalmia is a rare congenital malformation that affects 0.6/10,000 liveborn infants. It is usually associated with central nervous system malformations, aneuploidies, cytomegalovirus infection and mental retardation and it can also be part of genetic conditions such as Fraser, Goltz, Goldenhar, Waardenburg and Lenz syndromes. Neonatal prognosis depends on whether anophthalmia is an isolated malformation, or it is associated with other defects or part of a syndrome. A healthy 43-year-old woman, G4 P3 with three previous healthy children, was referred to our clinic for a routine obstetric ultrasound at 28 weeks' gestation. The fetal eye globes and lenses could not be seen on two-dimensional (2D) ultrasound, which led to the diagnosis of bilateral congenital anophthalmia. No other fetal malformations were detected. At 30 weeks' gestation, a three-dimensional (3D) ultrasound was performed using the rendering mode and "reverse face" view. Using this technique, the absence of both eye globes could be clearly seen through a "slit". 3D-ultrasound allowed the parents to better understand their child's problem and possible postnatal implications. Fetal magnetic resonance imaging (MRI) was also performed, to study the fetal cortex in more detail. This exam revealed right cerebral hemisphere sulci and gyri hypoplasia. At 41 1/7 weeks, she went into spontaneous labor and delivered vaginally a 3525 g male infant with Apgar scores of 9 and 10. Postnatal exams confirmed bilateral congenital anophthalmia. This is the first case report in the literature of prenatal diagnosis of bilateral anophthalmia using 3D "reverse face" view ultrasound and MRI. Copyright © 2012. Published by Elsevier B.V.

Utility of Magnetic Resonance Imaging in Cardiac Venous Anatomic Variants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eckart, Robert E.; Leitch, W. Shad; Shry, Eric A.

2003-06-15

The incidence of persistent left superior venacava (PLSVC) is approximately 0.5% in the general population; however,the coexistent absence of the right SVC has a reported incidence in tertiary centers of 0.1%. The vast majority of reports are limited to pediatric cardiology. Likewise, sinus of Valsalva aneurysm is a rare congenital anomaly, with a reported incidence of 0.1-3.5% of all congenital heart defects. We present a 71-year-old patient undergoing preoperative evaluation for incidental finding of aortic root aneurysm,and found to have all three in coexistence. Suggestive findings were demonstrated on cardiac catheterization and definitive diagnosis was made by magnetic resonance imaging.more » The use of MRI for the diagnosis of asymptomatic adult congenital heart disease will be reviewed.« less

Patterns of magnetic resonance imaging abnormalities in symptomatic patients with Krabbe disease correspond to phenotype.

PubMed

Abdelhalim, Ahmed N; Alberico, Ronald A; Barczykowski, Amy L; Duffner, Patricia K

2014-02-01

Initial magnetic resonance imaging studies of individuals with Krabbe disease were analyzed to determine whether the pattern of abnormalities corresponded to the phenotype. This was a retrospective, nonblinded study. Families/patients diagnosed with Krabbe disease submitted medical records and magnetic resonance imaging discs for central review. Institutional review board approval/informed consents were obtained. Sixty-four magnetic resonance imaging scans were reviewed by two neuroradiologists and a child neurologist according to phenotype: early infantile (onset 0-6 months) = 39 patients; late infantile (onset 7-12 months) = 10 patients; later onset (onset 13 months-10 years) = 11 patients; adolescent (onset 11-20 years) = one patient; and adult (21 years or greater) = three patients. Local interpretations were compared with central review. Magnetic resonance imaging abnormalities differed among phenotypes. Early infantile patients had a predominance of increased intensity in the dentate/cerebellar white matter as well as changes in the deep cerebral white matter. Later onset patients did not demonstrate involvement in the dentate/cerebellar white matter but had extensive involvement of the deep cerebral white matter, parieto-occipital region, and posterior corpus callosum. Late infantile patients exhibited a mixed pattern; 40% had dentate/cerebellar white matter involvement while all had involvement of the deep cerebral white matter. Adolescent/adult patients demonstrated isolated corticospinal tract involvement. Local and central reviews primarily differed in interpretation of the early infantile phenotype. Analysis of magnetic resonance imaging in a large cohort of symptomatic patients with Krabbe disease demonstrated imaging abnormalities correspond to specific phenotypes. Knowledge of these patterns along with typical clinical signs/symptoms should promote earlier diagnosis and facilitate treatment. Copyright © 2014 Elsevier Inc. All rights reserved.

Current technological advances in magnetic resonance with critical impact for clinical diagnosis and therapy.

PubMed

Runge, Val M

2013-12-01

The last 5 years of technological advances with major impact on clinical magnetic resonance (MR) are discussed, with greater emphasis on those that are most recent. These developments have already had a critical positive effect on clinical diagnosis and therapy and presage continued rapid improvements for the next 5 years. This review begins with a discussion of 2 topics that encompass the breadth of MR, in terms of anatomic applications, contrast media, and MR angiography. Subsequently, innovations are discussed by anatomic category, picking the areas with the greatest development, starting with the brain, moving forward to the liver and kidney, and concluding with the musculoskeletal system, breast, and prostate. Two final topics are then considered, which will likely, with time, become independent major fields in their own right, interventional MR and MR positron emission tomography (PET).The next decade will bring a new generation of MR contrast media, with research focused on substantial improvements (>100-fold) in relaxivity (contrast effect), thus providing greater efficacy, safety, and tissue targeting. Magnetic resonance angiography will see major advances because of the use of compressed sensing, in terms of spatial and temporal resolution, with movement away from nondynamic imaging. The breadth of available techniques and tissue contrast has greatly expanded in brain imaging, benefiting both from the introduction of new basic categories of imaging techniques, such as readout-segmented echo planar imaging and 3D fast spin echo imaging with variable flip angles, and from new refinements specific to anatomic areas, such as double inversion recovery and MP2RAGE. Liver imaging has benefited from the development of techniques to easily and rapidly assess lipid, and will see, overall, a marked improvement in the next 5 years from new techniques on the verge of clinical introduction, such as controlled aliasing in parallel imaging results in higher acceleration

Clinical and Magnetic Resonance Imaging Findings of Neurotoxocariasis.

PubMed

Sánchez, Sofia S; García, Hector H; Nicoletti, Alessandra

2018-01-01

Human toxocariasis is one of the most prevalent helminthiases worldwide. Toxocara canis larvae can cross the blood-brain barrier leading to the neurotoxocariasis. The clinical presentation consists of a wide spectrum of neurological manifestations, but asymptomatic infection is probably common. Neurotoxocariasis is not a frequent diagnosis probably due to the non-specific nature of its symptoms as well as the lack of confirmatory diagnostic tests. Diagnosis of neurotoxocariasis is based on the presence of a high titer of anti- Toxocara antibody in the cerebrospinal fluid or in the serum, presence of eosinophilia in the serum or cerebrospinal fluid, and clinical and radiological improvement after anthelmintic therapy; however, universally accepted diagnostic criteria are lacking. Magnetic resonance imaging (MRI) findings include single or multiple, subcortical, cortical or white matter hyperintense lesions, best visualized on FLAIR and T2-weighted imaging, and usually isointense or hypointense on T1. These imaging findings are suggestive but not specific to neurotoxocariasis. Definitive diagnosis is made by histological confirmation, but it is rarely followed. This review provides an overview of the clinical manifestations, management options, and MRI findings of neurotoxocariasis.

Clinical and Magnetic Resonance Imaging Findings of Neurotoxocariasis

PubMed Central

Sánchez, Sofia S.; García, Hector H.; Nicoletti, Alessandra

2018-01-01

Human toxocariasis is one of the most prevalent helminthiases worldwide. Toxocara canis larvae can cross the blood–brain barrier leading to the neurotoxocariasis. The clinical presentation consists of a wide spectrum of neurological manifestations, but asymptomatic infection is probably common. Neurotoxocariasis is not a frequent diagnosis probably due to the non-specific nature of its symptoms as well as the lack of confirmatory diagnostic tests. Diagnosis of neurotoxocariasis is based on the presence of a high titer of anti-Toxocara antibody in the cerebrospinal fluid or in the serum, presence of eosinophilia in the serum or cerebrospinal fluid, and clinical and radiological improvement after anthelmintic therapy; however, universally accepted diagnostic criteria are lacking. Magnetic resonance imaging (MRI) findings include single or multiple, subcortical, cortical or white matter hyperintense lesions, best visualized on FLAIR and T2-weighted imaging, and usually isointense or hypointense on T1. These imaging findings are suggestive but not specific to neurotoxocariasis. Definitive diagnosis is made by histological confirmation, but it is rarely followed. This review provides an overview of the clinical manifestations, management options, and MRI findings of neurotoxocariasis. PMID:29472889

Quantum transport in coupled resonators enclosed synthetic magnetic flux

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, L., E-mail: jinliang@nankai.edu.cn

Quantum transport properties are instrumental to understanding quantum coherent transport processes. Potential applications of quantum transport are widespread, in areas ranging from quantum information science to quantum engineering, and not restricted to quantum state transfer, control and manipulation. Here, we study light transport in a ring array of coupled resonators enclosed synthetic magnetic flux. The ring configuration, with an arbitrary number of resonators embedded, forms a two-arm Aharonov–Bohm interferometer. The influence of magnetic flux on light transport is investigated. Tuning the magnetic flux can lead to resonant transmission, while half-integer magnetic flux quantum leads to completely destructive interference and transmissionmore » zeros in an interferometer with two equal arms. -- Highlights: •The light transport is investigated through ring array of coupled resonators enclosed synthetic magnetic field. •Aharonov–Bohm ring interferometer of arbitrary configuration is investigated. •The half-integer magnetic flux quantum leads to destructive interference and transmission zeros for two-arm at equal length. •Complete transmission is available via tuning synthetic magnetic flux.« less

Hyperpolarized Magnetic Resonance: A Novel Technique for the In Vivo Assessment of Cardiovascular Disease

PubMed Central

Schroeder, Marie A.; Clarke, Kieran; Neubauer, Stefan; Tyler, Damian J.

2011-01-01

Non-invasive imaging plays a central role in cardiovascular disease for determining diagnosis, prognosis, and optimizing patient management. Recent experimental studies have demonstrated that monitoring hyperpolarized 13C-labelled tracers with magnetic resonance imaging and spectroscopy (MRI and MRS) offers a new way to investigate the normal and diseased heart, and that the technology may be useful in patients with heart disease. In this review, we show how hyperpolarized 13C-labelled tracers are generated and have been applied experimentally, and outline the methodological advances currently underway to enable translation of hyperpolarized 13C MRI and MRS into the clinic. Using hyperpolarized 13C-labelled metabolites and metabolic MRI and MRS could help assessment of many human cardiovascular diseases, including coronary artery disease, heart failure and metabolic cardiomyopathies. We discuss the clinical areas in which the technology may, in the future, aid in the diagnosis and management of patients with cardiovascular diseases, including dynamic investigations of in vivo metabolism, coronary angiography and quantitative perfusion imaging. It is possible that, in the future, hyperpolarized magnetic resonance will play a major role in clinical cardiology. PMID:21969318

The utility of magnetic resonance imaging in the diagnosis and management of pediatric benign ovarian lesions.

PubMed

Emil, Sherif; Youssef, Fouad; Arbash, Ghaidaa; Baird, Robert; Laberge, Jean-Martin; Puligandla, Pramod; Albuquerque, Pedro

2018-01-31

The utility of magnetic resonance imaging (MRI) in the diagnosis and management of pediatric ovarian lesions has not been well defined. A retrospective review of all girls who underwent MRI evaluation of ovarian masses during the period 2009-2015 was performed. The accuracy of MRI was evaluated by comparing results with surgical findings, pathology reports, and subsequent imaging. The influence of the MRI on the treatment plan was specifically explored. Eighteen girls, 12-17years of age, underwent 27 MRIs, subsequent to ultrasound identification of ovarian lesions. Of 9 neoplastic lesions diagnosed on MRI, 8 (89%) were confirmed by surgical and pathological findings. Of 18 functional lesions, 17 (94.4%) were confirmed pathologically or by resolution on subsequent imaging. Twenty MRI exams (74%) directly influenced the treatment plan, by leading to appropriate operative intervention in 9 and appropriate observation in 11. The extent of ovarian resection was guided by MRI findings in 8 of 9 (89%) neoplastic lesions. For characterizing lesions as neoplastic, the sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of MRI were 89%, 94%, 94%, 89%, and 93% respectively. MRI can differentiate functional from neoplastic pediatric ovarian masses, and guide ovarian resection in appropriate cases. II. Copyright © 2018. Published by Elsevier Inc.

Tumor Size of Invasive Breast Cancer on Magnetic Resonance Imaging and Conventional Imaging (Mammogram/Ultrasound): Comparison with Pathological Size and Clinical Implications.

PubMed

Haraldsdóttir, K H; Jónsson, Þ; Halldórsdóttir, A B; Tranberg, K-G; Ásgeirsson, K S

2017-03-01

In Landspitali University Hospital, magnetic resonance imaging is used non-selectively in addition to mammogram and ultrasound in the preoperative assessment of breast cancer patients. The aim of this study was to assess invasive tumor size on imaging, compare with pathological size and evaluate the impact of magnetic resonance imaging on the type of surgery performed. All women with invasive breast cancer, diagnosed in Iceland, between 2007 and 2009 were reviewed retrospectively. In all, 438 of 641 (68%) patients diagnosed had preoperative magnetic resonance imaging. Twelve patients treated with neoadjuvant chemotherapy were excluded and 65 patients with multifocal or contralateral disease were assessed separately. Correlations between microscopic and radiologic tumor sizes were relatively weak. All imaging methods were inaccurate especially for large tumors, resulting in an overall underestimation of tumor size for these tumors. Magnetic resonance imaging under- and overestimated pathological tumor size by more than 10 mm in 16/348 (4.6%) and 26/348 patients (7.5%), respectively. In 19 patients (73%), overestimation of size was seen exclusively on magnetic resonance imaging. For tumors under- or overestimated by magnetic resonance imaging, the mastectomy rates were 56% and 65%, respectively, compared to an overall mastectomy rate of 43%. Of 51 patients diagnosed with multifocal disease on pathology, 19 (37%) were diagnosed by mammogram or ultrasound and 40 (78%) by magnetic resonance imaging resulting in a total detection rate of 84% (43 patients). Fourteen (3%) patients were diagnosed preoperatively with contralateral disease. Of those tumors, all were detected on magnetic resonance imaging but seven (50%) were also detected on mammogram or ultrasound or both. Our results suggest that routine use of magnetic resonance imaging may result in both under- and overestimation of tumor size and increase mastectomy rates in a small proportion of patients. Magnetic

Magnetic resonance imaging of pancreatitis: An update

PubMed Central

Manikkavasakar, Sriluxayini; AlObaidy, Mamdoh; Busireddy, Kiran K; Ramalho, Miguel; Nilmini, Viragi; Alagiyawanna, Madhavi; Semelka, Richard C

2014-01-01

Magnetic resonance (MR) imaging plays an important role in the diagnosis and staging of acute and chronic pancreatitis and may represent the best imaging technique in the setting of pancreatitis due to its unmatched soft tissue contrast resolution as well as non-ionizing nature and higher safety profile of intravascular contrast media, making it particularly valuable in radiosensitive populations such as pregnant patients, and patients with recurrent pancreatitis requiring multiple follow-up examinations. Additional advantages include the ability to detect early forms of chronic pancreatitis and to better differentiate adenocarcinoma from focal chronic pancreatitis. This review addresses new trends in clinical pancreatic MR imaging emphasizing its role in imaging all types of acute and chronic pancreatitis, pancreatitis complications and other important differential diagnoses that mimic pancreatitis. PMID:25356038

Does non-echo-planar diffusion-weighted magnetic resonance imaging have a role in assisting the clinical diagnosis of cholesteatoma in selected cases?

PubMed

Nash, R; Lingam, R K; Chandrasekharan, D; Singh, A

2018-03-01

To determine the diagnostic performance of diffusion-weighted magnetic resonance imaging in the assessment of patients with suspected, but not clinically evident, cholesteatoma. A retrospective analysis of a prospectively collected database of non-echo-planar diffusion-weighted magnetic resonance imaging studies (using a half-Fourier single-shot turbo-spin echo sequence) was conducted. Clinical records were retrospectively reviewed to determine indications for imaging and operative findings. Seventy-eight investigations in 74 patients with suspected cholesteatoma aged 5.7-79.2 years (mean, 41.7 years) were identified. Operative confirmation was available in 44 ears. Diagnostic accuracy of the imaging technique was calculated using operative findings as a 'gold standard'. Sensitivity of the investigation was examined via comparison with clinically evident cholesteatoma. The accuracy of diffusion-weighted magnetic resonance imaging in assessment of suspected cholesteatoma was 63.6 per cent. The imaging technique was significantly less accurate in assessment of suspected cholesteatoma than clinically evident disease (p < 0.001). Computed tomography and diffusion-weighted magnetic resonance imaging may be complementary in assessment of suspected cholesteatoma, but should be used with caution, and clinical judgement is paramount.

Allan Cormack, Computerized Axial Tomography (CAT), and Magnetic Resonance

Science.gov Websites

Radiopharmaceuticals, DOE Technical Report, 1977 Emission Computed Tomography: A New Technique for the Quantitative Extending the Power of Nuclear Magnetic Resonance Techniques Magnetic Resonance Imaging Research Top Some

Consensus Recommendations of the Multiple Sclerosis Study Group and Portuguese Neuroradiological Society for the Use of the Magnetic Resonance Imaging in Multiple Sclerosis in Clinical Practice: Part 1.

PubMed

Abreu, Pedro; Pedrosa, Rui; Sá, Maria José; Cerqueira, João; Sousa, Lívia; Da Silva, Ana Martins; Pinheiro, Joaquim; De Sá, João; Batista, Sónia; Simões, Rita Moiron; Pereira, Daniela Jardim; Vilela, Pedro; Vale, José

2018-05-30

Magnetic resonance imaging is established as a recognizable tool in the diagnosis and monitoring of multiple sclerosis patients. In the present, among multiple sclerosis centers, there are different magnetic resonance imaging sequences and protocols used to study multiple sclerosis that may hamper the optimal use of magnetic resonance imaging in multiple sclerosis. In this context, the Group of Studies of Multiple Sclerosis and the Portuguese Society of Neuroradiology, after a joint discussion, appointed a committee of experts to create recommendations adapted to the national reality on the use of magnetic resonance imaging in multiple sclerosis. The purpose of this document is to publish the first Portuguese consensus recommendations on the use of magnetic resonance imaging in multiple sclerosis in clinical practice. The Group of Studies of Multiple Sclerosis and the Portuguese Society of Neuroradiology, after discussion of the topic in national meetings and after a working group meeting held in Figueira da Foz on May 2017, have appointed a committee of experts that have developed by consensus several standard protocols on the use of magnetic resonance imaging in the diagnosis and follow-up of multiple sclerosis. The document obtained was based on the best scientific evidence and expert opinion. Subsequently, the majority of Portuguese multiple sclerosis consultants and departments of neuroradiology scrutinized and reviewed the consensus paper; comments and suggestions were considered. Technical magnetic resonance imaging protocols regarding diagnostic, monitoring and the recommended information to be included in the magnetic resonance imaging report will be published in a separate paper. We provide some practical guidelines to promote standardized strategies to be applied in the clinical practice setting of Portuguese healthcare professionals regarding the use of magnetic resonance imaging in multiple sclerosis. We hope that these first Portuguese magnetic

Magnetic resonance imaging of the pediatric neck: an overview.

PubMed

Shekdar, Karuna V; Mirsky, David M; Kazahaya, Ken; Bilaniuk, Larissa T

2012-08-01

Evaluation of neck lesions in the pediatric population can be a diagnostic challenge, for which magnetic resonance (MR) imaging is extremely valuable. This article provides an overview of the value and utility of MR imaging in the evaluation of pediatric neck lesions, addressing what the referring clinician requires from the radiologist. Concise descriptions and illustrations of MR imaging findings of commonly encountered pathologic entities in the pediatric neck, including abnormalities of the branchial apparatus, thyroglossal duct anomalies, and neoplastic processes, are given. An approach to establishing a differential diagnosis is provided, and critical points of information are summarized. Copyright © 2012 Elsevier Inc. All rights reserved.

Clinical Benefit of 3 Tesla Magnetic Resonance Imaging Rescanning in Patients With Focal Epilepsy and Negative 1.5 Tesla Magnetic Resonance Imaging.

PubMed

Ladino, Lady D; Balaguera, Pedro; Rascovsky, Simon; Delgado, Jorge; Llano, Juan; Hernández-Ronquillo, Lizbeth; Gómez-Arias, Bety; Téllez-Zenteno, José F

2016-01-01

Magnetic resonance imaging is an essential tool in the pre-surgical evaluation of patients with drug-resistant epilepsy. Our aim was to assess the value of re-imaging patients with focal drug-resistant epilepsy. Thirty patients with negative or non-conclusive 1.5 Tesla magnetic resonance imaging were rescanned with 1.5T and 3T. All of them had previous 1.5 scans with no seizure protocol in a non-specialized center. Two neuroradiologists who were blinded to prior imaging results randomly reviewed the magnetic resonance images. Kappa score was used to assess the reliability. Mean age of patients was 30 (SD ± 11) years. The intra-observer agreement for the first radiologist was 0.74 for 1.5T and 0.71 for 3T. In the second radiologist it was 0.82 and 0.66, respectively. Three lesions (10%) were identified by general radiologists in non-specialized centers using a 1.5T standard protocol. In our center a consensus between two neuroradiologists using epilepsy protocol identified seven lesions (23%) using 1.5T and 10 (33%) using 3T (p < 0.01). In 28% of patients this additional information resulted in a change in clinical management. 3T magnetic resonance imaging rescanning improves the diagnostic yield in patients with focal epilepsy and previous negative 1.5T magnetic resonance imaging. Use of 3T magnetic resonance imaging, epilepsy protocols, and interpretation by experienced neuroradiologists is highly recommended.

Magnetic resonance imaging of the knee

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mink, J.H.; Reicher, M.A.; Crues, J.V.

1987-01-01

Introducing a comprehensive, practical guide to the use of magnetic resonance imaging (MRI) in detecting and evaluating knee disorders and planning arthroscopic surgery) This book integrates MRI findings with pertinent anatomy, physiology, and clinical signs to assist radiologists in selecting imaging protocols and interpreting scans. Detailed chapters focus on magnetic resonance imaging of the menisci and ligaments and evaluation of osteonecrosis, osteochondrosis, and osteochondritis. The authors demonstrate the potential of MRI for diagnosing various knee disorders such as arthritis, fractures, popliteal cysts, synovial disease, plicae, popliteal artery aneurysms, tumors, and bone marrow disorders.

Dynamic nuclear polarization in a magnetic resonance force microscope experiment.

PubMed

Issac, Corinne E; Gleave, Christine M; Nasr, Paméla T; Nguyen, Hoang L; Curley, Elizabeth A; Yoder, Jonilyn L; Moore, Eric W; Chen, Lei; Marohn, John A

2016-04-07

We report achieving enhanced nuclear magnetization in a magnetic resonance force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic nuclear polarization (DNP) effect. In our experiments a microwire coplanar waveguide delivered radiowaves to excite nuclear spins and microwaves to excite electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both electron and proton spin resonance were observed as a change in the mechanical resonance frequency of a nearby cantilever having a micron-scale nickel tip. NMR signal, not observable from Curie-law magnetization at 0.6 T, became observable when microwave irradiation was applied to saturate the electron spins. The resulting NMR signal's size, buildup time, dependence on microwave power, and dependence on irradiation frequency was consistent with a transfer of magnetization from electron spins to nuclear spins. Due to the presence of an inhomogeneous magnetic field introduced by the cantilever's magnetic tip, the electron spins in the sample were saturated in a microwave-resonant slice 10's of nm thick. The spatial distribution of the nuclear polarization enhancement factor ε was mapped by varying the frequency of the applied radiowaves. The observed enhancement factor was zero for spins in the center of the resonant slice, was ε = +10 to +20 for spins proximal to the magnet, and was ε = -10 to -20 for spins distal to the magnet. We show that this bipolar nuclear magnetization profile is consistent with cross-effect DNP in a ∼10(5) T m(-1) magnetic field gradient. Potential challenges associated with generating and using DNP-enhanced nuclear magnetization in a nanometer-resolution magnetic resonance imaging experiment are elucidated and discussed.

I. I. Rabi, Nuclear Magnetic Resonance (NMR), and Radar

Science.gov Websites

dropdown arrow Site Map A-Z Index Menu Synopsis I. I. Rabi, Nuclear Magnetic Resonance (NMR), and Radar Nobel Prize in Physics "for his resonance method for recording the magnetic properties of atomic the atomic clock, the laser and the diagnostic scanning of the human body by nuclear magnetic

Breed-Specific Magnetic Resonance Imaging Characteristics of Necrotizing Encephalitis in Dogs

PubMed Central

Flegel, Thomas

2017-01-01

Diagnosing necrotizing encephalitis, with its subcategories of necrotizing leukoencephalitis and necrotizing meningoencephalitis, based on magnetic resonance imaging alone can be challenging. However, there are breed-specific imaging characteristics in both subcategories that allow establishing a clinical diagnosis with a relatively high degree of certainty. Typical breed specific imaging features, such as lesion distribution, signal intensity, contrast enhancement, and gross changes of brain structure (midline shift, ventriculomegaly, and brain herniation) are summarized here, using current literature, for the most commonly affected canine breeds: Yorkshire Terrier, French Bulldog, Pug, and Chihuahua. PMID:29255715

Cost-Effectiveness of Magnetic Resonance Imaging with a New Contrast Agent for the Early Diagnosis of Alzheimer's Disease

PubMed Central

Biasutti, Maria; Dufour, Natacha; Ferroud, Clotilde; Dab, William; Temime, Laura

2012-01-01

Background Used as contrast agents for brain magnetic resonance imaging (MRI), markers for beta-amyloid deposits might allow early diagnosis of Alzheimer's disease (AD). We evaluated the cost-effectiveness of such a diagnostic test, MRI+CLP (contrastophore-linker-pharmacophore), should it become clinically available. Methodology/Principal Findings We compared the cost-effectiveness of MRI+CLP to that of standard diagnosis using currently available cognition tests and of standard MRI, and investigated the impact of a hypothetical treatment efficient in early AD. The primary analysis was based on the current French context for 70-year-old patients with Mild Cognitive Impairment (MCI). In alternative “screen and treat” scenarios, we analyzed the consequences of systematic screenings of over-60 individuals (either population-wide or restricted to the ApoE4 genotype population). We used a Markov model of AD progression; model parameters, as well as incurred costs and quality-of-life weights in France were taken from the literature. We performed univariate and probabilistic multivariate sensitivity analyses. The base-case preferred strategy was the standard MRI diagnosis strategy. In the primary analysis however, MRI+CLP could become the preferred strategy under a wide array of scenarios involving lower cost and/or higher sensitivity or specificity. By contrast, in the “screen and treat” analyses, the probability of MRI+CLP becoming the preferred strategy remained lower than 5%. Conclusions/Significance It is thought that anti-beta-amyloid compounds might halt the development of dementia in early stage patients. This study suggests that, even should such treatments become available, systematically screening the over-60 population for AD would only become cost-effective with highly specific tests able to diagnose early stages of the disease. However, offering a new diagnostic test based on beta-amyloid markers to elderly patients with MCI might prove cost

Cost-effectiveness of magnetic resonance imaging with a new contrast agent for the early diagnosis of Alzheimer's disease.

PubMed

Biasutti, Maria; Dufour, Natacha; Ferroud, Clotilde; Dab, William; Temime, Laura

2012-01-01

Used as contrast agents for brain magnetic resonance imaging (MRI), markers for beta-amyloid deposits might allow early diagnosis of Alzheimer's disease (AD). We evaluated the cost-effectiveness of such a diagnostic test, MRI+CLP (contrastophore-linker-pharmacophore), should it become clinically available. We compared the cost-effectiveness of MRI+CLP to that of standard diagnosis using currently available cognition tests and of standard MRI, and investigated the impact of a hypothetical treatment efficient in early AD. The primary analysis was based on the current French context for 70-year-old patients with Mild Cognitive Impairment (MCI). In alternative "screen and treat" scenarios, we analyzed the consequences of systematic screenings of over-60 individuals (either population-wide or restricted to the ApoE4 genotype population). We used a Markov model of AD progression; model parameters, as well as incurred costs and quality-of-life weights in France were taken from the literature. We performed univariate and probabilistic multivariate sensitivity analyses. The base-case preferred strategy was the standard MRI diagnosis strategy. In the primary analysis however, MRI+CLP could become the preferred strategy under a wide array of scenarios involving lower cost and/or higher sensitivity or specificity. By contrast, in the "screen and treat" analyses, the probability of MRI+CLP becoming the preferred strategy remained lower than 5%. It is thought that anti-beta-amyloid compounds might halt the development of dementia in early stage patients. This study suggests that, even should such treatments become available, systematically screening the over-60 population for AD would only become cost-effective with highly specific tests able to diagnose early stages of the disease. However, offering a new diagnostic test based on beta-amyloid markers to elderly patients with MCI might prove cost-effective.

Quantitative magnetic resonance micro-imaging methods for pharmaceutical research.

PubMed

Mantle, M D

2011-09-30

The use of magnetic resonance imaging (MRI) as a tool in pharmaceutical research is now well established and the current literature covers a multitude of different pharmaceutically relevant research areas. This review focuses on the use of quantitative magnetic resonance micro-imaging techniques and how they have been exploited to extract information that is of direct relevance to the pharmaceutical industry. The article is divided into two main areas. The first half outlines the theoretical aspects of magnetic resonance and deals with basic magnetic resonance theory, the effects of nuclear spin-lattice (T(1)), spin-spin (T(2)) relaxation and molecular diffusion upon image quantitation, and discusses the applications of rapid magnetic resonance imaging techniques. In addition to the theory, the review aims to provide some practical guidelines for the pharmaceutical researcher with an interest in MRI as to which MRI pulse sequences/protocols should be used and when. The second half of the article reviews the recent advances and developments that have appeared in the literature concerning the use of quantitative micro-imaging methods to pharmaceutically relevant research. Copyright © 2010 Elsevier B.V. All rights reserved.

Recent trends in high spin sensitivity magnetic resonance

NASA Astrophysics Data System (ADS)

Blank, Aharon; Twig, Ygal; Ishay, Yakir

2017-07-01

Magnetic resonance is a very powerful methodology that has been employed successfully in many applications for about 70 years now, resulting in a wealth of scientific, technological, and diagnostic data. Despite its many advantages, one major drawback of magnetic resonance is its relatively poor sensitivity and, as a consequence, its bad spatial resolution when examining heterogeneous samples. Contemporary science and technology often make use of very small amounts of material and examine heterogeneity on a very small length scale, both of which are well beyond the current capabilities of conventional magnetic resonance. It is therefore very important to significantly improve both the sensitivity and the spatial resolution of magnetic resonance techniques. The quest for higher sensitivity led in recent years to the development of many alternative detection techniques that seem to rival and challenge the conventional ;old-fashioned; induction-detection approach. The aim of this manuscript is to briefly review recent advances in the field, and to provide a quantitative as well as qualitative comparison between various detection methods with an eye to future potential advances and developments. We first offer a common definition of sensitivity in magnetic resonance to enable proper quantitative comparisons between various detection methods. Following that, up-to-date information about the sensitivity capabilities of the leading recently-developed detection approaches in magnetic resonance is provided, accompanied by a critical comparison between them and induction detection. Our conclusion from this comparison is that induction detection is still indispensable, and as such, it is very important to look for ways to significantly improve it. To do so, we provide expressions for the sensitivity of induction-detection, derived from both classical and quantum mechanics, that identify its main limiting factors. Examples from current literature, as well as a description of

Bayesian estimation of multicomponent relaxation parameters in magnetic resonance fingerprinting.

PubMed

McGivney, Debra; Deshmane, Anagha; Jiang, Yun; Ma, Dan; Badve, Chaitra; Sloan, Andrew; Gulani, Vikas; Griswold, Mark

2018-07-01

To estimate multiple components within a single voxel in magnetic resonance fingerprinting when the number and types of tissues comprising the voxel are not known a priori. Multiple tissue components within a single voxel are potentially separable with magnetic resonance fingerprinting as a result of differences in signal evolutions of each component. The Bayesian framework for inverse problems provides a natural and flexible setting for solving this problem when the tissue composition per voxel is unknown. Assuming that only a few entries from the dictionary contribute to a mixed signal, sparsity-promoting priors can be placed upon the solution. An iterative algorithm is applied to compute the maximum a posteriori estimator of the posterior probability density to determine the magnetic resonance fingerprinting dictionary entries that contribute most significantly to mixed or pure voxels. Simulation results show that the algorithm is robust in finding the component tissues of mixed voxels. Preliminary in vivo data confirm this result, and show good agreement in voxels containing pure tissue. The Bayesian framework and algorithm shown provide accurate solutions for the partial-volume problem in magnetic resonance fingerprinting. The flexibility of the method will allow further study into different priors and hyperpriors that can be applied in the model. Magn Reson Med 80:159-170, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

IMAGING DIAGNOSIS-MAGNETIC RESONANCE IMAGING FEATURES OF CRANIOMANDIBULAR OSTEOPATHY IN AN AIREDALE TERRIER.

PubMed

Matiasovic, Matej; Caine, Abby; Scarpante, Elena; Cherubini, Giunio Bruto

2016-05-01

An Airedale Terrier was presented for evaluation of depression and reluctance to be touched on the head. Magnetic resonance (MR) imaging of the head was performed. The images revealed bone lesions affecting the calvarium at the level of the coronal suture and left mandibular ramus, with focal cortical destruction, expansion, and reactive new bone formation. Skull lesions were hypointense on T1-weighted sequences, hyperintense on T2-weighted sequences, and showed an intense and homogeneous enhancement after gadolinium administration. Reactive new bone formation and periosteal proliferation were confirmed histopathologically. The clinical signs, imaging findings, and histopathological examination were consistent with craniomandibular osteopathy. © 2015 American College of Veterinary Radiology.

[Role of magnetic resonance imaging in the diagnosis of juvenile dermato-myositis and polymyositis in Chinese children].

PubMed

Lai, J M; Wu, F Q; Zhou, Z X; Yuan, X Y; Su, G X; Li, S N; Yan, Y C; Zhu, J; Kang, M

2016-10-02

Objective: To evaluate the utility of magnetic resonance imaging (MRI) in diagnosis of juvenile dermatomyositis and polymyositis (JDM-PM) in children. Method: Fifty-four patients with JDM-PM in the active stage were enrolled in the study group. Twelve patients with benign acute childhood myositis and forty patients with juvenile idiopathic arthritis (JIA) complicated with myositis were enrolled as controls. MRI imaging of thighs was performed in all patients, fast spin echo T1WI, T2WI, and STIR were obtained in all patients.Muscle biopsy was performed in 41/54 patients with JDM-PM. We compared the value of MRI in diagnosis of JDM-PM with muscle biopsy, electromyography and serum aspartate transaminase (AST), alanine transaminase (ALT), creatine kinase (CK), isoenzyme of creatine kinase (CKMB), lactate dehydrogenase (LDH), hydroxybutyrate dehydrogenase (HBDH) levels. Continuous normally distributed variables were reported as means and continuous non-normally distributed variables as median. Chi-square test and Fisher exact test were used to test differences between MRI and other categorical variables. Result: A total of 54 patients were included. Twenty-seven patients were male and the others were female. Average age of the patients was (7.1±3.5) years (2-13 years); 45(83%) paitests were JDM cases and 9(17%) patients had JPM. All patients had MRI examination. Of the 54 patients, 53 had multiple myositis; 10 out of 50 (19%) patients received second MRI after treatment, 6 out of 10 patients had normal findings, 4 patients showed obviously improved images; 41 out of 54 patients underwent muscle biopsy; 22 out of 41 patients had inflammatory cells infiltration and muscle fiber degeneration. The results of the muscle enzyme tests are as follows: 27 (50%) patients had elevated AST, 24 (44%) patients had elevated ALT, 22 (41%) patients had elevated CK, 18(33%) patients had elevated CKMB, and LDH rose in 30 (56%) patients, HBDH rose in 28(52%) patients. These results

Magnetic resonance cholangiopancreatography in the diagnosis of pancreas divisum: a systematic review and meta-analysis.

PubMed

Rustagi, Tarun; Njei, Basile

2014-08-01

This study aimed to perform a structured meta-analysis of all eligible studies to assess the overall diagnostic use of magnetic resonance cholangiopancreatography (MRCP) alone or with secretin enhancement (secretin-enhanced MRCP [S-MRCP]) in the detection of pancreas divisum. Two authors independently performed a comprehensive search of PubMed, MEDLINE, and the Cochrane Library from inception to September 2013. Studies were included if they allowed construction of 2 × 2 contingency tables of MRCP and/or S-MRCP compared with criterion standard. DerSimonian-Laird random effect models were used to estimate the pooled sensitivity, specificity, specificity, and quantitative receiver operating characteristics. Of 51 citations, 10 studies with 1474 patients were included. Secretin-enhanced MRCP had a higher overall diagnostic performance than MRCP (S-MRCP: pooled sensitivity, 86% [95% confidence interval (CI), 77%-93%]; specificity, 97% [95% CI, 94%-99%]; and area under the curve, 0.93 ± 0.056 compared with MRCP: sensitivity, 52% [95% CI, 45%-59%]; specificity, 97% [95% CI, 94%-99%]; and area under the curve, 0.76 ± 0.104). Pooled diagnostic odds ratios were 72.19 (95% CI, 5.66-938.8) and 23.39 (95% CI, 7.93-69.02) for S-MRCP and MRCP, respectively. Visual inspection of the funnel plot showed low potential for publication bias. Secretin-enhanced MRCP has a much higher diagnostic accuracy than MRCP and should be preferred for diagnosis of pancreas divisum.

Functional Magnetic Resonance Imaging

ERIC Educational Resources Information Center

Voos, Avery; Pelphrey, Kevin

2013-01-01

Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

Magnetic resonance imaging of pelvic endometriosis.

PubMed

Méndez Fernández, R; Barrera Ortega, J

Endometriosis is common in women of reproductive age; it can cause pelvic pain and infertility. It is important to diagnose endometriosis and to thoroughly evaluate its extension, especially when surgical treatment is being considered. Magnetic resonance imaging (MRI) with careful examination technique and interpretation enables more accurate and complete diagnosis and staging than ultrasonography, especially in cases of deep pelvic endometriosis. Furthermore, MRI can identify implants in sites that can be difficult to access in endoscopic or laparoscopic explorations. In this article, we describe the appropriate MRI protocol for the study of pelvic endometriosis and the MRI signs of pelvic organ involvement. It is necessary to know the subtle findings and to look for them so we can ensure that they are not overlooked. We describe clinical grading systems for endometriosis and review the diagnostic efficacy of MRI in comparison with other imaging techniques and surgery. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Tutte polynomial in functional magnetic resonance imaging

NASA Astrophysics Data System (ADS)

García-Castillón, Marlly V.

2015-09-01

Methods of graph theory are applied to the processing of functional magnetic resonance images. Specifically the Tutte polynomial is used to analyze such kind of images. Functional Magnetic Resonance Imaging provide us connectivity networks in the brain which are represented by graphs and the Tutte polynomial will be applied. The problem of computing the Tutte polynomial for a given graph is #P-hard even for planar graphs. For a practical application the maple packages "GraphTheory" and "SpecialGraphs" will be used. We will consider certain diagram which is depicting functional connectivity, specifically between frontal and posterior areas, in autism during an inferential text comprehension task. The Tutte polynomial for the resulting neural networks will be computed and some numerical invariants for such network will be obtained. Our results show that the Tutte polynomial is a powerful tool to analyze and characterize the networks obtained from functional magnetic resonance imaging.

[Magnetic resonance imaging in juvenile idiopathic arthritis: peculiarities of imaging children].

PubMed

Navallas, M; Rebollo Polo, M; Riaza, L; Muchart López, J; Maristany, T

2013-09-01

The term juvenile idiopathic arthritis (JIA) encompasses a heterogeneous group of arthritides with no known cause that begin before the age of 16 years and persist for at least 6 weeks. In recent decades, imaging techniques have acquired a fundamental role in the diagnosis and follow-up of JIA, owing to the unification of the different criteria for classification, which has strengthened the research in this field, and to the development of disease-modifying antirheumatic drugs. In this article, we briefly explain what JIA is. Moreover, we describe the role and limitations of plain-film radiography, ultrasonography, and magnetic resonance imaging (MRI). Finally, we review the MRI protocol and findings, and we comment on the differential diagnosis. Copyright © 2012 SERAM. Published by Elsevier Espana. All rights reserved.

Gadolinium Ethoxybenzyl Diethylenetriamine Pentaacetic Acid (Gd-EOB-DTPA)-Enhanced Magnetic Resonance Imaging and Multidetector-Row Computed Tomography for the Diagnosis of Hepatocellular Carcinoma: A Systematic Review and Meta-analysis.

PubMed

Ye, Feng; Liu, Jun; Ouyang, Han

2015-08-01

The purpose of this meta-analysis was to compare the diagnostic accuracy of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and multidetector-row computed tomography (MDCT) for hepatocellular carcinoma (HCC).Medline, Cochrane, EMBASE, and Google Scholar databases were searched until July 4, 2014, using combinations of the following terms: gadoxetic acid disodium, Gd-EOB-DTPA, multidetector CT, contrast-enhanced computed tomography, and magnetic resonance imaging. Inclusion criteria were as follows: confirmed diagnosis of primary HCC by histopathological examination of a biopsy specimen; comparative study of MRI using Gd-EOB-DTPA and MDCT for diagnosis of HCC; and studies that provided quantitative outcome data. The pooled sensitivity and specificity of the 2 methods were compared, and diagnostic accuracy was assessed with alternative-free response receiver-operating characteristic analysis.Nine studies were included in the meta-analysis, and a total of 1439 lesions were examined. The pooled sensitivity and specificity for 1.5T MRI were 0.95 and 0.96, respectively, for 3.0T MRI were 0.91 and 0.96, respectively, and for MDCT were 0.74 and 0.93, respectively. The pooled diagnostic odds ratio for 1.5T and 3.0T MRI was 242.96, respectively, and that of MDCT was 33.47. To summarize, Gd-EOB-DTPA-enhanced MRI (1.5T and 3.0T) has better diagnostic accuracy for HCC than MDCT.

Contrast agents in dynamic contrast-enhanced magnetic resonance imaging

PubMed Central

Yan, Yuling; Sun, Xilin; Shen, Baozhong

2017-01-01

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a noninvasive method to assess angiogenesis, which is widely used in clinical applications including diagnosis, monitoring therapy response and prognosis estimation in cancer patients. Contrast agents play a crucial role in DCE-MRI and should be carefully selected in order to improve accuracy in DCE-MRI examination. Over the past decades, there was much progress in the development of optimal contrast agents in DCE-MRI. In this review, we describe the recent research advances in this field and discuss properties of contrast agents, as well as their advantages and disadvantages. Finally, we discuss the research perspectives for improving this promising imaging method. PMID:28415647

In vivo Magnetic Resonance Imaging of Tumor Protease Activity

PubMed Central

Haris, Mohammad; Singh, Anup; Mohammed, Imran; Ittyerah, Ranjit; Nath, Kavindra; Nanga, Ravi Prakash Reddy; Debrosse, Catherine; Kogan, Feliks; Cai, Kejia; Poptani, Harish; Reddy, Damodar; Hariharan, Hari; Reddy, Ravinder

2014-01-01

Increased expression of cathepsins has diagnostic as well as prognostic value in several types of cancer. Here, we demonstrate a novel magnetic resonance imaging (MRI) method, which uses poly-L-glutamate (PLG) as an MRI probe to map cathepsin expression in vivo, in a rat brain tumor model. This noninvasive, high-resolution and non-radioactive method exploits the differences in the CEST signals of PLG in the native form and cathepsin mediated cleaved form. The method was validated in phantoms with known physiological concentrations, in tumor cells and in an animal model of brain tumor along with immunohistochemical analysis. Potential applications in tumor diagnosis and evaluation of therapeutic response are outlined. PMID:25124082

Contribution of Kinetic Characteristics of Axillary Lymph Nodes to the Diagnosis in Breast Magnetic Resonance Imaging

PubMed Central

Örgüç, Şebnem; Başara, Işıl; Pekindil, Gökhan; Coşkun, Teoman

2012-01-01

Objective: To assess the contribution of kinetic characteristics in the discrimination of malignant-benign axillary lymph nodes. Material and Methods: One hundred fifty-five female patients were included in the study. Following magnetic resonance imaging (MRI) examinations postprocessing applications were applied, dynamic curves were obtained from subtracted images. Types of dynamic curves were correlated with histopathological results in malignant cases or final clinical results in patients with no evidence of malignancy. Sensitivity, specificity, positive likehood ratio (+LHR), negative (−LHR) of dynamic curves characterizing the axillary lymph nodes were calculated. Results: A total of 178 lymph nodes greater than 8 mm were evaluated in 113 patients. Forty-six lymph nodes in 24 cases had malignant axillary involvement. 132 lymph nodes in 89 patients with benign diagnosis were included in the study. The sensitivity of type 3 curve as an indicator of malignancy was calculated as 89%. However the specificity, +LHR, −LHR were calculated as 14%, 1.04, 0.76 respectively. Conclusion: Since kinetic analysis of both benign and malignant axillary lymph nodes, rapid enhancement and washout (type 3) they cannot be used as a discriminator, unlike breast lesions. MRI, depending on the kinetic features of the axillary lymph nodes, is not high enough to be used in the clinical management of breast cancer patients. PMID:25207016

Age and the risk of anaplasia in magnetic resonance-nonenhancing supratentorial cerebral tumors.

PubMed

Barker, F G; Chang, S M; Huhn, S L; Davis, R L; Gutin, P H; McDermott, M W; Wilson, C B; Prados, M D

1997-09-01

It is often assumed that a cerebral lesion that is nonenhancing on a magnetic resonance imaging study with gadolinium contrast is a low grade tumor. Some physicians recommend observation rather than biopsy for such lesions. The authors prospectively evaluated the incidence of anaplastic tumor histology in a consecutive series of patients who presented to a neuro-oncology service with a nonenhancing mass of the cerebral hemisphere. During a 5-month period, the authors evaluated 31 patients who had a nonenhancing lesion in the cerebral hemisphere on initial magnetic resonance images. Thirty patients underwent stereotactic biopsy (27%) or open resection (73%). The median patient age was 36 years (range, 6-63 years). There was no mortality or permanent neurologic morbidity from surgery. Twenty-eight patients had pathologic confirmation of diagnosis while their lesions were still nonenhancing. Of these patients, 9 (32%) had Grade 3 lesions (anaplastic astrocytoma or oligoastrocytoma), 13 (43%) had Grade 2 lesions (astrocytoma, oligodendroglioma, or oligoastrocytoma), and 2 (7%) had Grade 1 lesions (dysembryoplastic neuroepithelial tumors). Two additional patients (ages 33 and 59 years) who developed enhancement within their lesions during preoperative periods of observation had glioblastomas at surgery. Logistic regression was used to relate patient age to the risk of anaplasia in a nonenhancing cerebral mass lesion. Older age predicted a significantly higher risk of anaplasia (P = 0.025). The model predicted that nonenhancing cerebral masses in patients older than 44 years were more likely to be anaplastic tumors than low grade tumors. There was no "safe" age below which low grade histology could be confidently assumed. Magnetic resonance-nonenhancing cerebral lesions may be histologically anaplastic, even in young patients. The risk of anaplasia in magnetic resonance-nonenhancing lesions increases significantly with patient age.

Adenomyosis with extensive glandular proliferation simulating infiltrating malignancy on magnetic resonance imaging.

PubMed

Funaki, Kaoru; Fukunishi, Hidenobu; Maeda, Tetsuo; Ohbayashi, Chiho; Yamaguchi, Satoshi

2011-05-01

We report a case of multicystic adenomyosis, which is an exceedingly rare benign tumor. The patient complained of an irregular menstrual cycle and abnormal genital bleeding that gradually increased in amount and frequency. The patient finally became severely anemic, and a hysterectomy was therefore performed. T2-weighted magnetic resonance imaging (MRI) indicated hyperplasia of the endometrium, with a myometrial lesion, where a high signal intensity multicystic mass was observed. The preoperative diagnosis was complicated by confusing MRI results. Postoperative macroscopic examination revealed a villous endometrium and a myometrium thickened with multiple small cysts containing serous transparent fluid. The final diagnosis, based on the hysterectomy specimen, was adenomyosis coexisting with simple endometrial hyperplasia. The MRI and positron emission tomography images are presented.

Grey-scale and colour Doppler ultrasound versus magnetic resonance imaging for the prenatal diagnosis of placenta accreta.

PubMed

Rezk, Mohamed Abd-Allah; Shawky, Mohamed

2016-01-01

To assess the effectiveness of grey-scale and colour Doppler ultrasound (US) versus magnetic resonance imaging (MRI) for the prenatal diagnosis of placenta accreta. A prospective observational study including a total of 74 patients with placenta previa and previous uterine scar (n = 74). Grey-scale and colour Doppler US was done followed by MRI by different observers to diagnose adherent placenta. Test validity of US and MRI were calculated. Maternal morbidity and mortality were also assessed. A total of 53 patients confirmed to have placenta accreta at operation. The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of US was 94.34, 91.67, 96.15 and 88% compared to 96.08, 87.50, 94.23 and 91.3% for MRI, respectively. The most relevant US sign was turbulent blood flow by colour Doppler, while dark intra-placental band was the most sensitive MRI sign. Venous thromboembolism (1.3%), bladder injury (29.7%), ureteric injury (18.9%), postoperative fever (10.8%), admission to ICU (50%) and re-operation (31.1%). Placenta accreta can be successfully diagnosed by grey-scale and colour Doppler US. MRI would be more likely suggested for either posteriorly or laterally situated placenta previa in order to exclude placental invasion.

New oil-in-water magnetic emulsion as contrast agent for in vivo magnetic resonance imaging (MRI).

PubMed

Ahmed, Naveed; Jaafar-Maalej, Chiraz; Eissa, Mohamed Mahmoud; Fessi, Hatem; Elaissari, Abdelhamid

2013-09-01

Nowadays, bio-imaging techniques are widely applied for the diagnosis of various diseased/tumoral tissues in the body using different contrast agents. Accordingly, the advancement in bionanotechnology research is enhanced in this regard. Among contrast agents used, superparamagnetic iron oxide nanoparticles were developed by many researchers and applied for in vive magnetic resonance imaging (MRI). In this study, a new oil-in-water magnetic emulsion was used as contrast agent in MRI, after being characterized in terms of particle size, iron oxide content, magnetic properties and colloidal stability using dynamic light scattering (DLS), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM) and zeta potential measurement techniques, respectively. The hydrodynamic size and magnetic content of the magnetic colloidal particles were found to be 250 nm and 75 wt%, respectively. In addition, the used magnetic emulsion possesses superparamagentic properties and high colloidal stability in aqueous medium. Then, the magnetic emulsion was highly diluted and administered intravenously to the Sprague dawley rats to be tested as contrast agent for in vivo MRI. In this preliminary study, MRI images showed significant enhancement in contrast, especially for T2 (relaxation time) contrast enhancement, indicating the distribution of magnetic colloidal nanoparticles within organs, like liver, spleen and kidneys of the Sprague dawley rats. In addition, it was found that 500 microL of the highly diluted magnetic emulsion (0.05 wt%) was found adequate for MRI analysis. This seems to be useful for further investigations especially in theranostic applications of magnetic emulsion.

Magnetic resonance imaging of the saccular otolithic mass.

PubMed Central

Sbarbati, A; Leclercq, F; Antonakis, K; Osculati, F

1992-01-01

The frog's inner ear was studied in vivo by high spatial resolution magnetic resonance imaging at 7 Tesla. The vestibule, the internal acoustic meatus, and the auditory tube have been identified. The large otolithic mass contained in the vestibule showed a virtual absence of magnetic resonance signal probably due to its composition of closely packed otoconia. Images Fig. 1 Fig. 2 Fig. 3 Fig. 5 PMID:1295875

Magnetic resonance techniques for investigation of multiple sclerosis

NASA Astrophysics Data System (ADS)

MacKay, Alex; Laule, Cornelia; Li, David K. B.; Meyers, Sandra M.; Russell-Schulz, Bretta; Vavasour, Irene M.

2014-11-01

Multiple sclerosis (MS) is a common neurological disease which can cause loss of vision and balance, muscle weakness, impaired speech, fatigue, cognitive dysfunction and even paralysis. The key pathological processes in MS are inflammation, edema, myelin loss, axonal loss and gliosis. Unfortunately, the cause of MS is still not understood and there is currently no cure. Magnetic resonance imaging (MRI) is an important clinical and research tool for MS. 'Conventional' MRI images of MS brain reveal bright lesions, or plaques, which demark regions of severe tissue damage. Conventional MRI has been extremely valuable for the diagnosis and management of people who have MS and also for the assessment of therapies designed to reduce inflammation and promote repair. While conventional MRI is clearly valuable, it lack pathological specificity and, in some cases, sensitivity to non-lesional pathology. Advanced MR techniques have been developed to provide information that is more sensitive and specific than what is available with clinical scanning. Diffusion tensor imaging and magnetization transfer provide a general but non-specific measure of the pathological state of brain tissue. MR spectroscopy provides concentrations of brain metabolites which can be related to specific pathologies. Myelin water imaging was designed to assess brain myelination and has proved useful for measuring myelin loss in MS. To combat MS, it is crucial that the pharmaceutical industry finds therapies which can reverse the neurodegenerative processes which occur in the disease. The challenge for magnetic resonance researchers is to design imaging techniques which can provide detailed pathological information relating to the mechanisms of MS therapies. This paper briefly describes the pathologies of MS and demonstrates how MS-associated pathologies can be followed using both conventional and advanced MR imaging protocols.

Magnetic resonance of porous media (MRPM): a perspective.

PubMed

Song, Yi-Qiao

2013-04-01

Porous media are ubiquitous in our environment and their application is extremely broad. The common connection between these diverse materials is the importance of the microstructure (μm to mm scale) in determining the physical, chemical and biological functions and properties. Magnetic resonance and its imaging modality have been essential for noninvasive characterization of these materials, in the development of catalysts, understanding cement hydration, fluid transport in rocks and soil, geological prospecting, and characterization of tissue properties for medical diagnosis. The past two decades have witnessed significant development of MRPM that couples advances in physics, chemistry and engineering with a broad range of applications. This article will summarize key advances in basic physics and methodology, examine their limitations and envision future R&D directions. Copyright © 2012 Elsevier Inc. All rights reserved.

Functional Magnetic Resonance Imaging in Alzheimer' Disease Drug Development.

PubMed

Holiga, Stefan; Abdulkadir, Ahmed; Klöppel, Stefan; Dukart, Juergen

2018-01-01

While now commonly applied for studying human brain function the value of functional magnetic resonance imaging in drug development has only recently been recognized. Here we describe the different functional magnetic resonance imaging techniques applied in Alzheimer's disease drug development with their applications, implementation guidelines, and potential pitfalls.

Iatrogenic hyperthermia during cardiac magnetic resonance imaging.

PubMed

Kussman, Barry D; Mulkern, Robert V; Holzman, Robert S

2004-10-01

We report the occurrence of accidental hyperthermia in a young child undergoing anesthesia for cardiac magnetic resonance imaging. Although the tendency during anesthesia is to develop hypothermia, the absorbed radiofrequency energy from magnetic resonance scanning is added to metabolic energy and must be balanced by appropriate heat loss to maintain normothermia. In addition to stressing the clinical importance of temperature monitoring, this report suggests that the recommended specific absorption rates to prevent excessive patient heating may need to be revised for infants and young children.

Silicon Nanoparticles as Hyperpolarized Magnetic Resonance Imaging Agents

PubMed Central

Aptekar, Jacob W.; Cassidy, Maja C.; Johnson, Alexander C.; Barton, Robert A.; Lee, Menyoung; Ogier, Alexander C.; Vo, Chinh; Anahtar, Melis N.; Ren, Yin; Bhatia, Sangeeta N.; Ramanathan, Chandrasekhar; Cory, David G.; Hill, Alison L.; Mair, Ross W.; Rosen, Matthew S.; Walsworth, Ronald L.

2014-01-01

Magnetic resonance imaging of hyperpolarized nuclei provides high image contrast with little or no background signal. To date, in-vivo applications of pre-hyperpolarized materials have been limited by relatively short nuclear spin relaxation times. Here, we investigate silicon nanoparticles as a new type of hyperpolarized magnetic resonance imaging agent. Nuclear spin relaxation times for a variety of Si nanoparticles are found to be remarkably long, ranging from many minutes to hours at room temperature, allowing hyperpolarized nanoparticles to be transported, administered, and imaged on practical time scales. Additionally, we demonstrate that Si nanoparticles can be surface functionalized using techniques common to other biologically targeted nanoparticle systems. These results suggest that Si nanoparticles can be used as a targetable, hyperpolarized magnetic resonance imaging agent with a large range of potential applications. PMID:19950973

Silicon nanoparticles as hyperpolarized magnetic resonance imaging agents.

PubMed

Aptekar, Jacob W; Cassidy, Maja C; Johnson, Alexander C; Barton, Robert A; Lee, Menyoung; Ogier, Alexander C; Vo, Chinh; Anahtar, Melis N; Ren, Yin; Bhatia, Sangeeta N; Ramanathan, Chandrasekhar; Cory, David G; Hill, Alison L; Mair, Ross W; Rosen, Matthew S; Walsworth, Ronald L; Marcus, Charles M

2009-12-22

Magnetic resonance imaging of hyperpolarized nuclei provides high image contrast with little or no background signal. To date, in vivo applications of prehyperpolarized materials have been limited by relatively short nuclear spin relaxation times. Here, we investigate silicon nanoparticles as a new type of hyperpolarized magnetic resonance imaging agent. Nuclear spin relaxation times for a variety of Si nanoparticles are found to be remarkably long, ranging from many minutes to hours at room temperature, allowing hyperpolarized nanoparticles to be transported, administered, and imaged on practical time scales. Additionally, we demonstrate that Si nanoparticles can be surface functionalized using techniques common to other biologically targeted nanoparticle systems. These results suggest that Si nanoparticles can be used as a targetable, hyperpolarized magnetic resonance imaging agent with a large range of potential applications.

Suppressing magnetic island growth by resonant magnetic perturbation

NASA Astrophysics Data System (ADS)

Yu, Q.; Günter, S.; Lackner, K.

2018-05-01

The effect of externally applied resonant magnetic perturbations (RMPs) on the growth of magnetic islands is investigated based on two-fluid equations. It is found that if the local bi-normal electron fluid velocity at the resonant surface is sufficiently large, static RMPs of the same helicity and of moderate amplitude can suppress the growth of magnetic islands in high-temperature plasmas. These islands will otherwise grow, driven by an unfavorable plasma current density profile and bootstrap current perturbation. These results indicate that the error field can stabilize island growth, if the error field amplitude is not too large and the local bi-normal electron fluid velocity is not too low. They also indicate that applied rotating RMPs with an appropriate frequency can be utilized to suppress island growth in high-temperature plasmas, even for a low bi-normal electron fluid velocity. A significant change in the local equilibrium plasma current density gradient by small amplitude RMPs is found for realistic plasma parameters, which are important for the island stability and are expected to be more important for fusion reactors with low plasma resistivity.

In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging.

PubMed

Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

2015-01-01

Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N'-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor.

In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging

PubMed Central

Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

2015-01-01

Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N′-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor. PMID:26316749

Investigation of suspected Guillain-Barre syndrome in childhood: what is the role for gadolinium enhanced magnetic resonance imaging of the spine?

PubMed

Smith, Nicholas; Pereira, John; Grattan-Smith, Padraic

2014-10-01

To review the role of gadolinium-enhanced magnetic resonance imaging of the spine in the diagnosis of paediatric Guillain-Barre syndrome and compare it with nerve conduction studies and cerebrospinal fluid analysis. A retrospective review of investigations undertaken in children admitted to our institution with acute Guillain-Barre syndrome over a 10-year period was performed. Seven of eight children (88%) displayed post-gadolinium nerve root enhancement consistent with Guillain-Barre syndrome. This compared with supportive nerve conduction studies in 21/24 children (88%) and cerebrospinal fluid protein analysis consistent with the diagnosis in 16/20 children (80%). Nerve conduction studies are the recognised 'gold standard' technique for confirming a clinical diagnosis of Guillain-Barre syndrome. In this study, a high positive rate was demonstrated. While more experience is necessary, this study and the literature support gadolinium enhanced magnetic resonance imaging of the spine as a valuable, although not necessarily superior, investigation in the diagnosis of Guillain-Barre syndrome. It may be of particular benefit when specialist neurophysiology expertise is unavailable. © 2010 The Authors. Journal compilation © 2010 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Magnetic resonance imaging features of esthesioneuroblastoma in three dogs and one cat.

PubMed

Söffler, Charlotte; Hartmann, Antje; Gorgas, Daniela; Ludewig, Eberhard; von Pückler, Kerstin; Kramer, Martin; Schmidt, Martin J

2016-10-12

Esthesioneuroblastoma is a rare malignant intranasal tumor that originates from the olfactory neuroepithelium of the upper nasal cavity, and can destroy the cribriform plate and expand into the neurocranium. Descriptions of the magnetic resonance features of esthesioneuroblastomas in animals are scarce. The objectives of this study were to report the magnetic resonance imaging features of esthesioneuroblastomas in order to determine distinct imaging characteristics that may help distinguish it from other intracranial tumor types. Magnetic resonance images of four patients with confirmed esthesioneuroblastomas were reviewed and compared with previously reported cases. The esthesioneuroblastomas appeared as oval-shaped, solitary lesions in the caudal nasal cavity that caused osteolysis of the cribriform plate and extended into the brain in all cases. Signal intensity was variable. Contrast enhancement was mild and varied from homogeneous to heterogeneous. A peripheral cystic component was found in two patients and was reported in only one previous case. Mass effect and white matter edema were marked to severe. Osteolysis of facial bones and extension into the facial soft tissues or retrobulbar space were not present in any of the cases, although this has been reported in the literature. A definitive diagnosis of esthesioneuroblastoma based on signal intensity or contrast behavior was not possible. Nevertheless, the presence of a mass in the caudal nasal cavity with extension into the neurocranium seems to be a feature highly suspicious of esthesioneuroblastoma. In contrast to other extra-cranial lesions, the extra-cranial mass was relatively small and destruction of facial bones seems to be rare.

Self-assembled gemcitabine-gadolinium nanoparticles for magnetic resonance imaging and cancer therapy.

PubMed

Li, Lele; Tong, Rong; Li, Mengyuan; Kohane, Daniel S

2016-03-01

Nanoparticles with combined diagnostic and therapeutic functions are promising tools for cancer diagnosis and treatment. Here, we demonstrate a theranostic nanoparticle that integrates an active gemcitabine metabolite and a gadolinium-based magnetic resonance imaging agent via a facile supramolecular self-assembly synthesis, where the anti-cancer drug gemcitabine-5'-monophosphate (a phosphorylated active metabolite of the anti-cancer drug gemcitabine) was used to coordinate with Gd(III) to self-assemble into theranostic nanoparticles. The formulation exhibits a strong T1 contrast signal for magnetic resonance imaging of tumors in vivo, with enhanced retention time. Furthermore, the nanoparticles did not require other inert nanocarriers or excipients and thus had an exceptionally high drug loading (55 wt%), resulting in the inhibition of MDA-MB-231 tumor growth in mice. Recent advances in nanoparticle-based drug delivery systems have spurred the development of "theranostic" multifunctional nanoparticles, which combine therapeutic and diagnostic functionalities in a single formulation. Developing simple and efficient synthetic strategies for the construction of nanotheranostics with high drug loading remains a challenge. Here, we demonstrate a theranostic nanoparticle that integrates high loadings of an active gemcitabine metabolite and a gadolinium-based magnetic resonance imaging agent via a facile synthesis. The nanoparticles were better T1 contrast agents than currently used Gd-DTPA and had prolonged retention in tumor. Moreover they exhibited enhanced in vivo antitumor activity compared to free drug in a breast cancer xenograft mouse model. The strategy provides a scalable way to fabricate nanoparticles that enables enhancement of both therapeutic and diagnostic capabilities. Published by Elsevier Ltd.

Artifacts Affecting Musculoskeletal Magnetic Resonance Imaging: Their Origins and Solutions.

PubMed

Roth, Eira; Hoff, Michael; Richardson, Michael L; Ha, Alice S; Porrino, Jack

2016-01-01

Among articles within the radiology literature, few present the manifestations of magnetic resonance imaging artifacts in a clinically oriented manner. Recognizing such artifacts is imperative given the increasing clinical use of magnetic resonance imaging and the emphasis by the American Board of Radiology on practical physics applications. The purpose of this article is to present magnetic resonance physics principles visually and conceptually in the context of common musculoskeletal radiology artifacts and their solutions, described using nonmathematical explanations. Copyright © 2016 Elsevier Inc. All rights reserved.

Clinical, radiographic, and magnetic resonance imaging findings of gastrocnemius musculotendinopathy in various dog breeds.

PubMed

Kaiser, Susanne M; Harms, Oliver; Konar, Martin; Staudacher, Anne; Langer, Anna; Thiel, Cetina; Kramer, Martin; Schaub, Sebastian; von Pückler, Kerstin H

2016-11-23

To describe clinical, radiographic, and magnetic resonance imaging (MRI) findings in 16 dogs diagnosed with gastrocnemius musculotendinopathy. Retrospective evaluation of medical records, radiographs, and MRI results, as well as follow-up completed by telephone questionnaire. Most dogs had chronic hindlimb lameness with no history of trauma or athletic activities. Clinical examination revealed signs of pain on palpation without stifle joint instability. Seven dogs had radiographic signs of osteophyte formation on the lateral fabella. Magnetic resonance imaging revealed T2 hyperintensity and uptake of contrast agent in the region of the origin of the gastrocnemius muscle. Changes were found in the lateral and medial heads of the gastrocnemius. Conservative treatment resulted in return to full function in 11 dogs. Two dogs showed partial restoration of normal function, one dog showed no improvement. Two dogs were lost to follow-up. Gastrocnemius musculotendinopathy is a potential cause of chronic hindlimb lameness in medium to large breed dogs. A history of athletic activity must not necessarily be present. Magnetic resonance imaging shows signal changes and uptake of contrast agent in the region of the origin of the gastrocnemius muscle. A combination of T1 pre- and post-contrast administration and T2 weighted sequences completed by a fat-suppressed sequence in the sagittal plane are well-suited for diagnosis. Conservative treatment generally results in return to normal function.

Towards Single Biomolecule Imaging via Optical Nanoscale Magnetic Resonance Imaging.

PubMed

Boretti, Alberto; Rosa, Lorenzo; Castelletto, Stefania

2015-09-09

Nuclear magnetic resonance (NMR) spectroscopy is a physical marvel in which electromagnetic radiation is charged and discharged by nuclei in a magnetic field. In conventional NMR, the specific nuclei resonance frequency depends on the strength of the magnetic field and the magnetic properties of the isotope of the atoms. NMR is routinely utilized in clinical tests by converting nuclear spectroscopy in magnetic resonance imaging (MRI) and providing 3D, noninvasive biological imaging. While this technique has revolutionized biomedical science, measuring the magnetic resonance spectrum of single biomolecules is still an intangible aspiration, due to MRI resolution being limited to tens of micrometers. MRI and NMR have, however, recently greatly advanced, with many breakthroughs in nano-NMR and nano-MRI spurred by using spin sensors based on an atomic impurities in diamond. These techniques rely on magnetic dipole-dipole interactions rather than inductive detection. Here, novel nano-MRI methods based on nitrogen vacancy centers in diamond are highlighted, that provide a solution to the imaging of single biomolecules with nanoscale resolution in-vivo and in ambient conditions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Magnetic resonance investigation of magnetic-labeled baker's yeast cells

NASA Astrophysics Data System (ADS)

Godoy Morais, J. P. M.; Azevedo, R. B.; Silva, L. P.; Lacava, Z. G. M.; Báo, S. N.; Silva, O.; Pelegrini, F.; Gansau, C.; Buske, N.; Safarik, I.; Safarikova, M.; Morais, P. C.

2004-05-01

In this study, the interaction of DMSA-coated magnetite nanoparticles (5 and 10 nm core-size) with Saccharomyces cerevisae was investigated using magnetic resonance (MR) and transmission electron microscopy (TEM). The TEM micrographs revealed magnetite nanoparticles attached externally to the cell wall. The MR data support the strong interaction among the nanoparticles supported by the cells. A remarkable shift in the resonance field was used as signature of particle attachment to the cell wall.

Granular convection observed by magnetic resonance imaging.

PubMed

Ehrichs, E E; Jaeger, H M; Karczmar, G S; Knight, J B; Kuperman, V Y; Nagel, S R

1995-03-17

Vibrations in a granular material can spontaneously produce convection rolls reminiscent of those seen in fluids. Magnetic resonance imaging provides a sensitive and noninvasive probe for the detection of these convection currents, which have otherwise been difficult to observe. A magnetic resonance imaging study of convection in a column of poppy seeds yielded data about the detailed shape of the convection rolls and the depth dependence of the convection velocity. The velocity was found to decrease exponentially with depth; a simple model for this behavior is presented here.

Interobserver agreement and diagnostic accuracy of brain magnetic resonance imaging in dogs.

PubMed

Leclerc, Mylène-Kim; d'Anjou, Marc-André; Blond, Laurent; Carmel, Éric Norman; Dennis, Ruth; Kraft, Susan L; Matthews, Andrea R; Parent, Joane M

2013-06-15

To evaluate interobserver agreement and diagnostic accuracy of brain MRI in dogs. Evaluation study. 44 dogs. 5 board-certified veterinary radiologists with variable MRI experience interpreted transverse T2-weighted (T2w), T2w fluid-attenuated inversion recovery (FLAIR), and T1-weighted-FLAIR; transverse, sagittal, and dorsal T2w; and T1-weighted-FLAIR postcontrast brain sequences (1.5 T). Several imaging parameters were scored, including the following: lesion (present or absent), lesion characteristics (axial localization, mass effect, edema, hemorrhage, and cavitation), contrast enhancement characteristics, and most likely diagnosis (normal, neoplastic, inflammatory, vascular, metabolic or toxic, or other). Magnetic resonance imaging diagnoses were determined initially without patient information and then repeated, providing history and signalment. For all cases and readers, MRI diagnoses were compared with final diagnoses established with results from histologic examination (when available) or with other pertinent clinical data (CSF analysis, clinical response to treatment, or MRI follow-up). Magnetic resonance scores were compared between examiners with κ statistics. Reading agreement was substantial to almost perfect (0.64 < κ < 0.86) when identifying a brain lesion on MRI; fair to moderate (0.14 < κ < 0.60) when interpreting hemorrhage, edema, and pattern of contrast enhancement; fair to substantial (0.22 < κ < 0.74) for dural tail sign and categorization of margins of enhancement; and moderate to substantial (0.40 < κ < 0.78) for axial localization, presence of mass effect, cavitation, intensity, and distribution of enhancement. Interobserver agreement was moderate to substantial for categories of diagnosis (0.56 < κ < 0.69), and agreement with the final diagnosis was substantial regardless of whether patient information was (0.65 < κ < 0.76) or was not (0.65 < κ < 0.68) provided. The present study found that whereas some MRI features such as edema

Magnetic resonance imaging with an optical atomic magnetometer

PubMed Central

Xu, Shoujun; Yashchuk, Valeriy V.; Donaldson, Marcus H.; Rochester, Simon M.; Budker, Dmitry; Pines, Alexander

2006-01-01

We report an approach for the detection of magnetic resonance imaging without superconducting magnets and cryogenics: optical atomic magnetometry. This technique possesses a high sensitivity independent of the strength of the static magnetic field, extending the applicability of magnetic resonance imaging to low magnetic fields and eliminating imaging artifacts associated with high fields. By coupling with a remote-detection scheme, thereby improving the filling factor of the sample, we obtained time-resolved flow images of water with a temporal resolution of 0.1 s and spatial resolutions of 1.6 mm perpendicular to the flow and 4.5 mm along the flow. Potentially inexpensive, compact, and mobile, our technique provides a viable alternative for MRI detection with substantially enhanced sensitivity and time resolution for various situations where traditional MRI is not optimal. PMID:16885210

Dynamical Nuclear Magnetic Resonance Imaging of Micron-scale Liquids

NASA Astrophysics Data System (ADS)

Sixta, Aimee; Choate, Alexandra; Maeker, Jake; Bogat, Sophia; Tennant, Daniel; Mozaffari, Shirin; Markert, John

We report our efforts in the development of Nuclear Magnetic Resonance Force Microscopy (NMRFM) for dynamical imaging of liquid media at the micron scale. Our probe contains microfluidic samples sealed in thin-walled (µm) quartz tubes, with a micro-oscillator sensor nearby in vacuum to maintain its high mechanical resonance quality factor. Using 10 µm spherical permalloy magnets at the oscillator tips, a 3D T1-resolved image of spin density can be obtained by reconstruction from our magnetostatics-modelled resonance slices; as part of this effort, we are exploring single-shot T1 measurements for faster dynamical imaging. We aim to further enhance imaging by using a 2 ω technique to eliminate artifact signals during the cyclic inversion of nuclear spins. The ultimate intent of these efforts is to perform magnetic resonance imaging of individual biological cells.

A Scalable Framework For Segmenting Magnetic Resonance Images

PubMed Central

Hore, Prodip; Goldgof, Dmitry B.; Gu, Yuhua; Maudsley, Andrew A.; Darkazanli, Ammar

2009-01-01

A fast, accurate and fully automatic method of segmenting magnetic resonance images of the human brain is introduced. The approach scales well allowing fast segmentations of fine resolution images. The approach is based on modifications of the soft clustering algorithm, fuzzy c-means, that enable it to scale to large data sets. Two types of modifications to create incremental versions of fuzzy c-means are discussed. They are much faster when compared to fuzzy c-means for medium to extremely large data sets because they work on successive subsets of the data. They are comparable in quality to application of fuzzy c-means to all of the data. The clustering algorithms coupled with inhomogeneity correction and smoothing are used to create a framework for automatically segmenting magnetic resonance images of the human brain. The framework is applied to a set of normal human brain volumes acquired from different magnetic resonance scanners using different head coils, acquisition parameters and field strengths. Results are compared to those from two widely used magnetic resonance image segmentation programs, Statistical Parametric Mapping and the FMRIB Software Library (FSL). The results are comparable to FSL while providing significant speed-up and better scalability to larger volumes of data. PMID:20046893

Ultra-small v-shaped gold split ring resonators for biosensing using fundamental magnetic resonance in the visible spectrum

NASA Astrophysics Data System (ADS)

Mauluidy Soehartono, Alana; Mueller, Aaron David; Tobing, Landobasa Yosef Mario; Chan, Kok Ken; Zhang, Dao Hua; Yong, Ken-Tye

2017-10-01

Strong light localization within metal nanostructures occurs by collective oscillations of plasmons in the form of electric and magnetic resonances. This so-called localized surface plasmon resonance (LSPR) has gained much interest in the development of low-cost sensing platforms in the visible spectrum. However, demonstrations of LSPR-based sensing are mostly limited to electric resonances due to the technological limitations for achieving magnetic resonances in the visible spectrum. In this work, we report the first demonstration of LSPR sensing based on fundamental magnetic resonance in the visible spectrum using ultrasmall gold v-shaped split ring resonators. Specifically, we show the ability for detecting adsorption of bovine serum albumin and cytochrome c biomolecules at monolayer levels, and the selective binding of protein A/G to immunoglobulin G.

Electrically detected magnetic resonance in a W-band microwave cavity

NASA Astrophysics Data System (ADS)

Lang, V.; Lo, C. C.; George, R. E.; Lyon, S. A.; Bokor, J.; Schenkel, T.; Ardavan, A.; Morton, J. J. L.

2011-03-01

We describe a low-temperature sample probe for the electrical detection of magnetic resonance in a resonant W-band (94 GHz) microwave cavity. The advantages of this approach are demonstrated by experiments on silicon field-effect transistors. A comparison with conventional low-frequency measurements at X-band (9.7 GHz) on the same devices reveals an up to 100-fold enhancement of the signal intensity. In addition, resonance lines that are unresolved at X-band are clearly separated in the W-band measurements. Electrically detected magnetic resonance at high magnetic fields and high microwave frequencies is therefore a very sensitive technique for studying electron spins with an enhanced spectral resolution and sensitivity.

Mesoscopic Magnetic Resonance Spectroscopy with a Remote Spin Sensor

NASA Astrophysics Data System (ADS)

Xie, Tianyu; Shi, Fazhan; Chen, Sanyou; Guo, Maosen; Chen, Yisheng; Zhang, Yixing; Yang, Yu; Gao, Xingyu; Kong, Xi; Wang, Pengfei; Tateishi, Kenichiro; Uesaka, Tomohiro; Wang, Ya; Zhang, Bo; Du, Jiangfeng

2018-06-01

Quantum sensing based on nitrogen-vacancy (N -V ) centers in diamond has been developed as a powerful tool for microscopic magnetic resonance. However, the reported sensor-to-sample distance is limited within tens of nanometers resulting from the cubic decrease of the signal of spin fluctuation with the increasing distance. Here we extend the sensing distance to tens of micrometers by detecting spin polarization rather than spin fluctuation. We detect the mesoscopic magnetic resonance spectra of polarized electrons of a pentacene-doped crystal, measure its two typical decay times, and observe the optically enhanced spin polarization. This work paves the way for the N -V -based mesoscopic magnetic resonance spectroscopy and imaging at ambient conditions.

Biological effects of exposure to magnetic resonance imaging: an overview

PubMed Central

Formica, Domenico; Silvestri, Sergio

2004-01-01

The literature on biological effects of magnetic and electromagnetic fields commonly utilized in magnetic resonance imaging systems is surveyed here. After an introduction on the basic principles of magnetic resonance imaging and the electric and magnetic properties of biological tissues, the basic phenomena to understand the bio-effects are described in classical terms. Values of field strengths and frequencies commonly utilized in these diagnostic systems are reported in order to allow the integration of the specific literature on the bio-effects produced by magnetic resonance systems with the vast literature concerning the bio-effects produced by electromagnetic fields. This work gives an overview of the findings about the safety concerns of exposure to static magnetic fields, radio-frequency fields, and time varying magnetic field gradients, focusing primarily on the physics of the interactions between these electromagnetic fields and biological matter. The scientific literature is summarized, integrated, and critically analyzed with the help of authoritative reviews by recognized experts, international safety guidelines are also cited. PMID:15104797

Magnetic resonance imaging spectrum of perinatal hypoxic-ischemic brain injury

PubMed Central

Varghese, Binoj; Xavier, Rose; Manoj, V C; Aneesh, M K; Priya, P S; Kumar, Ashok; Sreenivasan, V K

2016-01-01

Perinatal hypoxic–ischemic brain injury results in neonatal hypoxic–ischemic encephalopathy and serious long-term neurodevelopmental sequelae. Magnetic resonance imaging (MRI) of the brain is an ideal and safe imaging modality for suspected hypoxic–ischemic injury. The pattern of injury depends on brain maturity at the time of insult, severity of hypotension, and duration of insult. Time of imaging after the insult influences the imaging findings. Mild to moderate hypoperfusion results in germinal matrix hemorrhages and periventricular leukomalacia in preterm neonates and parasagittal watershed territory infarcts in full-term neonates. Severe insult preferentially damages the deep gray matter in both term and preterm infants. However, associated frequent perirolandic injury is seen in term neonates. MRI is useful in establishing the clinical diagnosis, assessing the severity of injury, and thereby prognosticating the outcome. Familiarity with imaging spectrum and insight into factors affecting the injury will enlighten the radiologist to provide an appropriate diagnosis. PMID:27857456

Magnetic Resonance Enterography to Assess Multifocal and Multicentric Bowel Endometriosis.

PubMed

Nyangoh Timoh, Krystel; Stewart, Zelda; Benjoar, Mikhael; Beldjord, Selma; Ballester, Marcos; Bazot, Marc; Thomassin-Naggara, Isabelle; Darai, Emile

To prospectively determine the accuracy of magnetic resonance enterography (MRE) compared with conventional magnetic resonance imaging (MRI) for multifocal (i.e., multiple lesions affecting the same digestive segment) and multicentric (i.e., multiple lesions affecting several digestive segments) bowel endometriosis. A prospective study (Canadian Task Force classification II-2). Tenon University Hospital, Paris, France. Patients with MRI-suspected colorectal endometriosis scheduled for colorectal resection from April 2014 to February 2016 were included. Patients underwent both 1.5-Tesla MRI and MRE as well as laparoscopically assisted and open colorectal resections. The diagnostic performance of MRI and MRE was evaluated for sensitivity, specificity, positive and negative predictive values, accuracy, and positive and negative likelihood ratios (LRs). The interobserver variability of the experienced and junior radiologists was quantified using weighted statistics. Forty-seven patients were included. Twenty-two (46.8%) patients had unifocal lesions, 14 (30%) had multifocal lesions, and 11 (23.4%) had multicentric lesions. The sensitivity, specificity, positive LR, and negative LR for the diagnosis of multifocal lesions were 0.29 (6/21), 1.00 (23/24), 15.36, and 0.71 for MRI and 0.57 (12/21), 0.89 (23/25), 4.95, and 0.58 for MRE. The sensitivity, specificity, positive LR, and negative LR for the diagnosis of multicentric lesions were 0.18 (1/11), 1.00 (1/1), 15, and 0.80 for MRI and 0.46 (5/11), 0.92 (33/36), 5.45, and 0.60 for MRE. Lower accuracies for MRI compared with MRE to diagnose multicentric (p = .01) and multifocal lesions (p = .004) were noted. The interobserver agreement for MRE was good for both multifocality (κ = 0.80) and multicentricity (κ = 0.61). MRE has better accuracy for diagnosing multifocal and multicentric bowel endometriosis than conventional MRI. Copyright © 2018. Published by Elsevier Inc.

Sinonasal papilloma: what influences the decision to request a magnetic resonance imaging scan?

PubMed

Kasbekar, A V; Swords, C; Attlmayr, B; Kulkarni, T; Swift, A C

2018-06-18

Computed tomography is the standard pre-operative imaging modality for sinonasal papilloma. The complementary use of magnetic resonance imaging as an additional investigation is debated. This study aimed to establish whether magnetic resonance imaging can accurately detect tumour extent and is a useful adjunct to computed tomography. A retrospective review was conducted on 19 patients with sinonasal papilloma. The interpretation of computed tomography and magnetic resonance imaging scans, by three clinicians, was conducted by comparing prediction of tumour extent. The perceived necessity of magnetic resonance imaging was compared between clinicians. The addition of magnetic resonance imaging improved accuracy of pre-operative interpretation; specifically, this finding was significant in cases with frontal sinus involvement. Surgeons were more likely than a radiologist to request magnetic resonance imaging, particularly when computed tomography indicated frontal sinus disease. Pre-operative combined magnetic resonance imaging and computed tomography helped predict disease in the frontal sinus better than computed tomography alone. A close working relationship between the ENT and radiology departments is important for accurate tumour localisation.

Ferromagnetic linewidth measurements employing electrodynamic model of the magnetic plasmon resonance

NASA Astrophysics Data System (ADS)

Krupka, Jerzy; Aleshkevych, Pavlo; Salski, Bartlomiej; Kopyt, Pawel

2018-02-01

The mode of uniform precession, or Kittel mode, in a magnetized ferromagnetic sphere, has recently been proven to be the magnetic plasmon resonance. In this paper we show how to apply the electrodynamic model of the magnetic plasmon resonance for accurate measurements of the ferromagnetic resonance linewidth ΔH. Two measurement methods are presented. The first one employs Q-factor measurements of the magnetic plasmon resonance coupled to the resonance of an empty metallic cavity. Such coupled modes are known as magnon-polariton modes, i.e. hybridized modes between the collective spin excitation and the cavity excitation. The second one employs direct Q-factor measurements of the magnetic plasmon resonance in a filter setup with two orthogonal semi-loops used for coupling. Q-factor measurements are performed employing a vector network analyser. The methods presented in this paper allow one to extend the measurement range of the ferromagnetic resonance linewidth ΔH well beyond the limits of the commonly used measurement standards in terms of the size of the samples and the lowest measurable linewidths. Samples that can be measured with the newly proposed methods may have larger size as compared to the size of samples that were used in the standard methods restricted by the limits of perturbation theory.

Imaging of the hip joint. Computed tomography versus magnetic resonance imaging

NASA Technical Reports Server (NTRS)

Lang, P.; Genant, H. K.; Jergesen, H. E.; Murray, W. R.

1992-01-01

The authors reviewed the applications and limitations of computed tomography (CT) and magnetic resonance (MR) imaging in the assessment of the most common hip disorders. Magnetic resonance imaging is the most sensitive technique in detecting osteonecrosis of the femoral head. Magnetic resonance reflects the histologic changes associated with osteonecrosis very well, which may ultimately help to improve staging. Computed tomography can more accurately identify subchondral fractures than MR imaging and thus remains important for staging. In congenital dysplasia of the hip, the position of the nonossified femoral head in children less than six months of age can only be inferred by indirect signs on CT. Magnetic resonance imaging demonstrates the cartilaginous femoral head directly without ionizing radiation. Computed tomography remains the imaging modality of choice for evaluating fractures of the hip joint. In some patients, MR imaging demonstrates the fracture even when it is not apparent on radiography. In neoplasm, CT provides better assessment of calcification, ossification, and periosteal reaction than MR imaging. Magnetic resonance imaging, however, represents the most accurate imaging modality for evaluating intramedullary and soft-tissue extent of the tumor and identifying involvement of neurovascular bundles. Magnetic resonance imaging can also be used to monitor response to chemotherapy. In osteoarthrosis and rheumatoid arthritis of the hip, both CT and MR provide more detailed assessment of the severity of disease than conventional radiography because of their tomographic nature. Magnetic resonance imaging is unique in evaluating cartilage degeneration and loss, and in demonstrating soft-tissue alterations such as inflammatory synovial proliferation.

Diagnosis and classification of chondral knee injuries: comparison between magnetic resonance imaging and arthroscopy.

PubMed

Danieli, Marcus Vinicius; Guerreiro, João Paulo Fernandes; Queiroz, Alexandre deOliveira; Pereira, Hamilton daRosa; Tagima, Susi; Marini, Marcelo Garcia; Cataneo, Daniele Cristina

2016-05-01

To compare the magnetic resonance imaging (MRI) findings of patients undergoing knee arthroscopy for chondral lesions. The hypothesis was that MRI displays low sensitivity in the diagnosis and classification of chondral injuries. A total of 83 knees were evaluated. The MRIs were performed using the same machine (GE SIGNA HDX 1.45 T). The MRI results were compared with the arthroscopy findings, and an agreement analysis was performed. Thirty-eight of the 83 MRI exams were evaluated by another radiologist for inter-observer agreement analysis. These analyses were performed using the kappa (κ) coefficient. The highest incidence of chondral injury was in the patella (14.4 %). The κ coefficient was 0.31 for the patellar surface; 0.38 for the trochlea; 0.46 for the medial femoral condyle; 0.51 for the lateral femoral condyle; and 0.19 for the lateral plateau. After dividing the injuries into two groups (ICRS Grades 0-II and Grades III and IV), the following κ coefficients were obtained as follows: 0.49 (patella); 0.53 (trochlea); 0.46 (medial femoral condyle); 0.43 (medial plateau); 0.67 (lateral femoral condyle); and 0.51 (lateral plateau). The MRI sensitivity was 76.4 % (patella), 88.2 % (trochlea), 69.7 % (medial femoral condyle), 85.7 % (medial plateau), 81.8 % (lateral femoral condyle) and 75 % (lateral plateau). Comparing the radiologists' evaluations, the following κ coefficients were obtained as follows: 0.73 (patella); 0.63 (trochlea); 0.84 (medial femoral condyle); 0.72 (medial plateau); 0.77 (lateral femoral condyle); and 0.91 (lateral plateau). Compared with arthroscopy, MRI displays moderate sensitivity for detecting and classifying chondral knee injuries. It is an important image method, but we must be careful in the assessment of patients with suspected chondral lesions. III.

BOLD magnetic resonance imaging in nephrology

PubMed Central

Hall, Michael E; Jordan, Jennifer H; Juncos, Luis A; Hundley, W Gregory; Hall, John E

2018-01-01

Magnetic resonance (MR) imaging, a non-invasive modality that provides anatomic and physiologic information, is increasingly used for diagnosis of pathophysiologic conditions and for understanding renal physiology in humans. Although functional MR imaging methods were pioneered to investigate the brain, they also offer powerful techniques for investigation of other organ systems such as the kidneys. However, imaging the kidneys provides unique challenges due to potential complications from contrast agents. Therefore, development of non-contrast techniques to study kidney anatomy and physiology is important. Blood oxygen level-dependent (BOLD) MR is a non-contrast imaging technique that provides functional information related to renal tissue oxygenation in various pathophysiologic conditions. Here we discuss technical considerations, clinical uses and future directions for use of BOLD MR as well as complementary MR techniques to better understand renal pathophysiology. Our intent is to summarize kidney BOLD MR applications for the clinician rather than focusing on the complex physical challenges that functional MR imaging encompasses; however, we briefly discuss some of those issues. PMID:29559807

Huygens’ Metasurfaces Enabled by Magnetic Dipole Resonance Tuning in Split Dielectric Nanoresonators

DOE PAGES

Liu, Sheng; Vaskin, Aleksandr; Campione, Salvatore; ...

2017-06-07

Dielectric metasurfaces that exploit the different Mie resonances of nanoscale dielectric resonators are a powerful platform for manipulating electromagnetic fields and can provide novel optical behavior. Here in this work, we experimentally demonstrate independent tuning of the magnetic dipole resonances relative to the electric dipole resonances of split dielectric resonators (SDRs). By increasing the split dimension, we observe a blue shift of the magnetic dipole resonance toward the electric dipole resonance. Therefore, SDRs provide the ability to directly control the interaction between the two dipole resonances within the same resonator. For example, we achieve the first Kerker condition by spectrallymore » overlapping the electric and magnetic dipole resonances and observe significantly suppressed backward scattering. Moreover, we show that a single SDR can be used as an optical nanoantenna that provides strong unidirectional emission from an electric dipole source.« less

Low losses left-handed materials with optimized electric and magnetic resonance

NASA Astrophysics Data System (ADS)

Zhou, Xin; Liu, Yahong; Zhao, Xiaopeng

2010-03-01

We propose that the losses in left-handed materials (LHMs) can be significantly affected by changing the coupling relationship between electric and magnetic resonance. A double bowknot shaped structure (DBS) is used to construct the LHMs. And the magnetic resonance of the DBS, which resonated in the case of lower and higher frequencies than the electric resonant dip, is studied in simulation and experiment by tailoring the structural parameters. The case of magnetic resonance located at low electric resonance frequencies band is confirmed to have relatively low losses. Using full wave simulation of prism shaped structure composed of DBS unit cells, we prove the negative refraction behavior in such a frame. This study can serve as a guide for designing other similar metal-dielectric-metal (MDM) in low losses at terahertz or higher frequencies.

Adjunctive role of preoperative liver magnetic resonance imaging for potentially resectable pancreatic cancer.

PubMed

Kim, Hyoung Woo; Lee, Jong-Chan; Paik, Kyu-Hyun; Kang, Jingu; Kim, Young Hoon; Yoon, Yoo-Seok; Han, Ho-Seong; Kim, Jaihwan; Hwang, Jin-Hyeok

2017-06-01

The adjunctive role of magnetic resonance imaging of the liver before pancreatic ductal adenocarcinoma has been unclear. We evaluated whether the combination of hepatic magnetic resonance imaging with multidetector computed tomography using a pancreatic protocol (pCT) could help surgeons select appropriate candidates and decrease the risk of early recurrence. We retrospectively enrolled 167 patients in whom complete resection was achieved without grossly visible residual tumor; 102 patients underwent pCT alone (CT group) and 65 underwent both hepatic magnetic resonance imaging and pCT (magnetic resonance imaging group). By adding hepatic magnetic resonance imaging during preoperative evaluation, hepatic metastases were newly discovered in 3 of 58 patients (5%) without hepatic lesions on pCT and 17 of 53 patients (32%) with indeterminate hepatic lesions on pCT. Patients with borderline resectability, a tumor size >3 cm, or preoperative carbohydrate antigen 19-9 level >1,000 U/mL had a greater rate of hepatic metastasis on subsequent hepatic magnetic resonance imaging. Among 167 patients in whom R0/R1 resection was achieved, the median overall survival was 18.2 vs 24.7 months (P = .020) and the disease-free survival was 8.5 vs 10.0 months (P = .016) in the CT and magnetic resonance imaging groups, respectively (median follow-up, 18.3 months). Recurrence developed in 82 (80%) and 43 (66%) patients in the CT and magnetic resonance imaging groups, respectively. The cumulative hepatic recurrence rate was greater in the CT group than in the magnetic resonance imaging group (P < .001). Preoperative hepatic magnetic resonance imaging should be considered in patients with potentially resectable pancreatic ductal adenocarcinoma, especially those with high tumor burden. Copyright © 2017 Elsevier Inc. All rights reserved.

Sensitivity and specificity of noncontrast magnetic resonance imaging reports in the diagnosis of type-II superior labral anterior-posterior lesions in the community setting.

PubMed

Connolly, Keith P; Schwartzberg, Randy S; Reuss, Bryan; Crumbie, David; Homan, Brad M

2013-02-20

Magnetic resonance imaging (MRI) has been suggested to be of high accuracy at academic institutions in the identification of superior labral tears; however, many Type-II superior labral anterior-posterior (SLAP) lesions encountered during arthroscopy have not been previously diagnosed with noncontrast images. This study evaluated the accuracy of diagnosing Type-II SLAP lesions in a community setting with use of noncontrast MRI and analyzed the effect that radiologist training and the scanner type or magnet strength had on sensitivity and specificity. One hundred and forty-four patients requiring repair of an arthroscopically confirmed Type-II SLAP lesion who had a noncontrast MRI examination performed within twelve months before the procedure were included in the sensitivity analysis. An additional 100 patients with arthroscopically confirmed, normal superior labral anatomy were identified for specificity analysis. The transcribed interpretations of the images by the radiologists were used to document the diagnosis of a SLAP lesion and were compared with the operative report. The magnet strength, type of MRI system (open or closed), and whether the radiologist had completed a musculoskeletal fellowship were also recorded. Noncontrast MRI identified SLAP lesions in fifty-four of 144 shoulders, yielding an overall sensitivity of 38% (95% confidence interval [CI] = 30%, 46%). Specificity was 94% (95% CI = 87%, 98%), with six SLAP lesions diagnosed in 100 shoulders that did not contain the lesion. Musculoskeletal fellowship-trained radiologists performed with higher sensitivity than those who had not completed the fellowship (46% versus 19%; p = 0.009). Our results demonstrate a low sensitivity and high specificity in the diagnosis of Type-II SLAP lesions with noncontrast MRI in this community setting. Musculoskeletal fellowship-trained radiologists had significantly higher sensitivities in accurately diagnosing the lesion than did radiologists without such training

Rotatable Small Permanent Magnet Array for Ultra-Low Field Nuclear Magnetic Resonance Instrumentation: A Concept Study.

PubMed

Vogel, Michael W; Giorni, Andrea; Vegh, Viktor; Pellicer-Guridi, Ruben; Reutens, David C

2016-01-01

We studied the feasibility of generating the variable magnetic fields required for ultra-low field nuclear magnetic resonance relaxometry with dynamically adjustable permanent magnets. Our motivation was to substitute traditional electromagnets by distributed permanent magnets, increasing system portability. The finite element method (COMSOL®) was employed for the numerical study of a small permanent magnet array to calculate achievable magnetic field strength, homogeneity, switching time and magnetic forces. A manually operated prototype was simulated and constructed to validate the numerical approach and to verify the generated magnetic field. A concentric small permanent magnet array can be used to generate strong sample pre-polarisation and variable measurement fields for ultra-low field relaxometry via simple prescribed magnet rotations. Using the array, it is possible to achieve a pre-polarisation field strength above 100 mT and variable measurement fields ranging from 20-50 μT with 200 ppm absolute field homogeneity within a field-of-view of 5 x 5 x 5 cubic centimetres. A dynamic small permanent magnet array can generate multiple highly homogeneous magnetic fields required in ultra-low field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) instruments. This design can significantly reduce the volume and energy requirements of traditional systems based on electromagnets, improving portability considerably.

Juvenile Dermatomyositis: Key Roles of Muscle Magnetic Resonance Imaging and Early Aggressive Treatment.

PubMed

Corral-Magaña, O; Bauzá-Alonso, A F; Escudero-Góngora, M M; Lacruz, L; Martín-Santiago, A

2017-09-12

Juvenile dermatomyositis is a rare systemic connective tissue disease with onset during childhood. It presents clinically with proximal muscle weakness and characteristic skin involvement. Diagnosis is based on the Bohan and Peter criteria, though many authors are now substituting biopsy with muscle magnetic resonance imaging (MRI) for both diagnosis and follow-up. Without intensive early treatment, complications such as calcinosis cutis and lipodystrophy can develop in the chronic phases of the disease. Early recognition is therefore key to management. We present a series of 5 patients who were diagnosed with Juvenile dermatomyositis on muscle MRI without undergoing muscle biopsy and who received early treatment. We draw attention to the usefulness of muscle MRI for the diagnosis of muscle involvement and to the importance of early initiation of intensive treatment to prevent complications. Copyright © 2017 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

Molecular aspects of magnetic resonance imaging and spectroscopy.

PubMed

Boesch, C

1999-01-01

Magnetic resonance imaging (MRI) is a well known diagnostic tool in radiology that produces unsurpassed images of the human body, in particular of soft tissue. However, the medical community is often not aware that MRI is an important yet limited segment of magnetic resonance (MR) or nuclear magnetic resonance (NMR) as this method is called in basic science. The tremendous morphological information of MR images sometimes conceal the fact that MR signals in general contain much more information, especially on processes on the molecular level. NMR is successfully used in physics, chemistry, and biology to explore and characterize chemical reactions, molecular conformations, biochemical pathways, solid state material, and many other applications that elucidate invisible characteristics of matter and tissue. In medical applications, knowledge of the molecular background of MRI and in particular MR spectroscopy (MRS) is an inevitable basis to understand molecular phenomenon leading to macroscopic effects visible in diagnostic images or spectra. This review shall provide the necessary background to comprehend molecular aspects of magnetic resonance applications in medicine. An introduction into the physical basics aims at an understanding of some of the molecular mechanisms without extended mathematical treatment. The MR typical terminology is explained such that reading of original MR publications could be facilitated for non-MR experts. Applications in MRI and MRS are intended to illustrate the consequences of molecular effects on images and spectra.

[Multiparameter magnetic resonance imaging in the diagnosis of cancer of the cervix uteri].

PubMed

Tarachkova, E V; Strel'tsova, O N; Panov, V O; Bazaeva, I Ya; Tyurin, I E

2015-01-01

Cancer of the cervix uteri (CCU) ranks third in the incidence of malignancies in women. The choice of CCU treatment mainly depends on the extent of the tumor process, i.e., the stage of the disease. Determining the stage of CCU is based on the clinical classification of the International Federation of Gynecology and Obstetrics (FIGO) (2009) and has a number of substantial limitations in evaluating parametrial invasion, tumor spread to the pelvic wall, and involvement of regional lymph nodes and in determining the true tumor sizes. Magnetic resonance imaging (MRI) is now the method of choice in staging invasive CCU. Multiparameter MRI will be able to enhance the efficiency of diagnosing microinvasive CCU as well (FIGO 2009), to plan surgical and/or chemoradiation treatment, to evaluate its efficiency, and to diagnose locally recurrent CCU.

State-of-the-art Magnetic Resonance Imaging in Vascular Thoracic Outlet Syndrome.

PubMed

Aghayev, Ayaz; Rybicki, Frank J

2015-05-01

Vascular thoracic outlet syndrome is caused by compression of subclavian/axillary vessels during their passage from the thoracic cavity to the axilla. Early diagnosis and treatment is important to prevent debilitating outcomes of vascular thoracic outlet syndrome. Contrast-enhanced three-dimensional (3D) magnetic resonance angiography (MRA) with equilibrium phase using provocative arm positioning is the optimal examination to determine presence, degree of vascular compression, and complications of vascular thoracic outlet syndrome. This article reviews thoracic outlet anatomy, disorders of the vascular component, and typical imaging findings by contrast-enhanced 3D MRA. Published by Elsevier Inc.

Magnetic Resonance Super-resolution Imaging Measurement with Dictionary-optimized Sparse Learning

NASA Astrophysics Data System (ADS)

Li, Jun-Bao; Liu, Jing; Pan, Jeng-Shyang; Yao, Hongxun

2017-06-01

Magnetic Resonance Super-resolution Imaging Measurement (MRIM) is an effective way of measuring materials. MRIM has wide applications in physics, chemistry, biology, geology, medical and material science, especially in medical diagnosis. It is feasible to improve the resolution of MR imaging through increasing radiation intensity, but the high radiation intensity and the longtime of magnetic field harm the human body. Thus, in the practical applications the resolution of hardware imaging reaches the limitation of resolution. Software-based super-resolution technology is effective to improve the resolution of image. This work proposes a framework of dictionary-optimized sparse learning based MR super-resolution method. The framework is to solve the problem of sample selection for dictionary learning of sparse reconstruction. The textural complexity-based image quality representation is proposed to choose the optimal samples for dictionary learning. Comprehensive experiments show that the dictionary-optimized sparse learning improves the performance of sparse representation.

[Possibilities of a software-based hybrid single photon emission computed tomography/magnetic resonance imaging in the diagnosis of complicated diabetic foot syndrome].

PubMed

Zavadovskaya, V D; Zorkal'tsev, M A; Udodov, V D; Zamyshevskaya, M A; Kilina, O Yu; Kurazhov, A P; Popov, K M

2015-01-01

To give the results of a software-based hybrid single photon emission computed tomography/magnetic resonance imaging (SPECT/MRI) in detecting osteomyelitis (OM) in patients with diabetic foot syndrome (DFS). Seventy-six patients (35 men and 41 women) (mean age, 59.4 +/- 7.1 years) with type 1 and 2 diabetes mellitus and suspected OM were examined. The investigation enrolled patients with neuropathic (n = 25), ischemic (n = 13), and mixed (n = 38) DFS. All the patients underwent (99m)Tc-HMPAO/ (99m)Tc-technefit labeled leukocyte scintigraphy; magnetic resonance imaging was performed in 30 patients. The results were combined using RView 9.06 software (Colin Studholme). Labeled leukocyte SPECT to Diagnose OM yielded 255 true positive (TP), 38 true negative (TN), 12 false negative (FP), and 1 false negative (FN) results. The accuracy of the technique was 82.9%. The FP results were due to the low resolution of the technique and to the small sizes of the object under study. One FN result was detected in a patient with ischemic DFS because of reduced blood flow. MRI to identify OM in patients with DFS provided 20 TP, 16 TN, 4 FP, and 2 FN results. Its diagnostic accuracy was 85.7%. The relative low specificity of MRI was associated with the presence of FP results due to the complexity of differential diagnosis of bone marrow edema and inflammatory infiltration. Assessing 42 hybrid SPECT/MR-images revealed 21 TP, 17 TN, 3 FP, and I FN results. The diagnostic accuracy was equal to 95.9%. Thus, comparing MRI (90.9% sensitivity and 80.0% specificity), labeled leukocyte scintigraphy (96.2% sensitivity and 76.0% specificity), and hybrid SPECT/MRI (95.5% sensitivity and 85.0% specificity) showed the high diagnostic efficiency of the latter.

Magnetic resonance imaging-compatible tactile sensing device based on a piezoelectric array.

PubMed

Hamed, Abbi; Masamune, Ken; Tse, Zion Tsz Ho; Lamperth, Michael; Dohi, Takeyoshi

2012-07-01

Minimally invasive surgery is a widely used medical technique, one of the drawbacks of which is the loss of direct sense of touch during the operation. Palpation is the use of fingertips to explore and make fast assessments of tissue morphology. Although technologies are developed to equip minimally invasive surgery tools with haptic feedback capabilities, the majority focus on tissue stiffness profiling and tool-tissue interaction force measurement. For greatly increased diagnostic capability, a magnetic resonance imaging-compatible tactile sensor design is proposed, which allows minimally invasive surgery to be performed under image guidance, combining the strong capability of magnetic resonance imaging soft tissue and intuitive palpation. The sensing unit is based on a piezoelectric sensor methodology, which conforms to the stringent mechanical and electrical design requirements imposed by the magnetic resonance environment The sensor mechanical design and the device integration to a 0.2 Tesla open magnetic resonance imaging scanner are described, together with the device's magnetic resonance compatibility testing. Its design limitations and potential future improvements are also discussed. A tactile sensing unit based on a piezoelectric sensor principle is proposed, which is designed for magnetic resonance imaging guided interventions.

[BILIARY HYPERTENSION IN CHRONIC PANCREATITIS AND PECULIARITIES OF ITS DIAGNOSIS].

PubMed

Kopchak, V M; Pylypchuk, V I; Khomyak, I V; Pererva, L O; Shevkolenko, G G; Davydenko, N G

2016-02-01

Possibilities of various diagnostic methods for biliary hypertension detection in chronic pancreatitis were analyzed. Biliary hypertension was revealed in 163 (31%) patients, suffering chronic pancreatitis. The laboratory investigations data, ultrasonographic investigation, computer tomography, endoscopic retrograde cholangiopancreatography, magnet-resonance cholangiopancreatography, intraoperative measurement of the biliary ducts width, intraoperative measurement of biliary pressure were applied for diagnosis. Endoscopic retrograde cholangiopancreatography, magnet-resonance cholangiopancreatography and intraoperative measurement of biliary pressure are considered the most sensitive methods for chronic pancreatitis diagnosis.

Magnetic resonance imaging and magnetic resonance spectroscopy in a young male patient with anti-N-methyl-D-aspartate receptor encephalitis and uncommon cerebellar involvement: A case report with review of the literature

PubMed Central

Felli, Valentina; Di Sibio, Alessandra; Gennarelli, Antonio; Patriarca, Lucia; Stratta, Paolo; Di Cesare, Ernesto; Rossi, Alessandro; Massimo, Gallucci

2015-01-01

We report a case of a 17-year-old man presenting with new onset psychiatric symptoms. Magnetic resonance imaging (MRI) and proton magnetic resonance (MR) spectroscopy revealed some lesions in the right cerebellar hemisphere and ipsilateral cerebellar tonsil suggestive of encephalitis. An extensive workup was negative for both infectious and neoplastic diseases and he was afterward diagnosed with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. This disorder is an autoimmune encephalitis, highly lethal but curable, predominantly found in young female with ovarian teratoma. He received methylprednisolone. His clinical findings gradually improve and he made a complete recovery. Accordingly, repeated brain MRI and proton MR spectroscopy showed a gradual reduction of the lesions; MRI taken six months after starting therapy showed complete resolution of the lesions. Our case shows that, although rare, anti-NMDAR encephalitis should be considered also in young men for whom a rapid onset of psychiatric neurological disorders cannot be explained by more frequent causes. Our report underlines also the usefulness of MRI and proton MR spectroscopic findings in the diagnosis and follow-up of this disease. PMID:26613928

Limits to magnetic resonance microscopy

NASA Astrophysics Data System (ADS)

Glover, Paul; Mansfield, Peter, Sir

2002-10-01

The last quarter of the twentieth century saw the development of magnetic resonance imaging (MRI) grow from a laboratory demonstration to a multi-billion dollar worldwide industry. There is a clinical body scanner in almost every hospital of the developed nations. The field of magnetic resonance microscopy (MRM), after mostly being abandoned by researchers in the first decade of MRI, has become an established branch of the science. This paper reviews the development of MRM over the last decade with an emphasis on the current state of the art. The fundamental principles of imaging and signal detection are examined to determine the physical principles which limit the available resolution. The limits are discussed with reference to liquid, solid and gas phase microscopy. In each area, the novel approaches employed by researchers to push back the limits of resolution are discussed. Although the limits to resolution are well known, the developments and applications of MRM have not reached their limit.

Prognostic Value of Pulmonary Vascular Resistance by Magnetic Resonance in Systolic Heart Failure

PubMed Central

Fabregat-Andrés, Óscar; Estornell-Erill, Jordi; Ridocci-Soriano, Francisco; Pérez-Boscá, José Leandro; García-González, Pilar; Payá-Serrano, Rafael; Morell, Salvador; Cortijo, Julio

2016-01-01

Background Pulmonary hypertension is associated with poor prognosis in heart failure. However, non-invasive diagnosis is still challenging in clinical practice. Objective We sought to assess the prognostic utility of non-invasive estimation of pulmonary vascular resistances (PVR) by cardiovascular magnetic resonance to predict adverse cardiovascular outcomes in heart failure with reduced ejection fraction (HFrEF). Methods Prospective registry of patients with left ventricular ejection fraction (LVEF) < 40% and recently admitted for decompensated heart failure during three years. PVRwere calculated based on right ventricular ejection fraction and average velocity of the pulmonary artery estimated during cardiac magnetic resonance. Readmission for heart failure and all-cause mortality were considered as adverse events at follow-up. Results 105 patients (average LVEF 26.0 ±7.7%, ischemic etiology 43%) were included. Patients with adverse events at long-term follow-up had higher values of PVR (6.93 ± 1.9 vs. 4.6 ± 1.7estimated Wood Units (eWu), p < 0.001). In multivariate Cox regression analysis, PVR ≥ 5 eWu(cutoff value according to ROC curve) was independently associated with increased risk of adverse events at 9 months follow-up (HR2.98; 95% CI 1.12-7.88; p < 0.03). Conclusions In patients with HFrEF, the presence of PVR ≥ 5.0 Wu is associated with significantly worse clinical outcome at follow-up. Non-invasive estimation of PVR by cardiac magnetic resonance might be useful for risk stratification in HFrEF, irrespective of etiology, presence of late gadolinium enhancement or LVEF. PMID:26840055

Evaluation of nonalcoholic fatty liver disease using magnetic resonance in obese children and adolescents.

PubMed

Benetolo, Patrícia O; Fernandes, Maria I M; Ciampo, Ieda R L Del; Elias-Junior, Jorge; Sawamura, Regina

2018-02-10

To determine the frequency of nonalcoholic fatty liver disease using nuclear magnetic resonance as a noninvasive method. This was a cross-sectional study conducted on 50 children and adolescents followed up at an outpatient obesity clinic. The subjects were submitted to physical examination, laboratory tests (transaminases, liver function tests, lipid profile, glycemia, and basal insulin) and abdominal nuclear magnetic resonance (calculation of hepatic, visceral, and subcutaneous fat). Nonalcoholic fatty liver disease was diagnosed in 14 (28%) participants, as a severe condition in eight (percent fat >18%), and as non-severe in four (percent fat from 9% to 18%). Fatty liver was associated with male gender, triglycerides, AST, ALT, AST/ALT ratio, and acanthosis nigricans. Homeostasis model assessment of insulin resistance and metabolic syndrome did not show an association with fatty liver. The frequency of nonalcoholic fatty liver disease in the present population of children and adolescents was lower than that reported in the international literature. It is suggested that nuclear magnetic resonance is an imaging exam that can be applied to children and adolescents, thus representing an effective noninvasive tool for the diagnosis of nonalcoholic fatty liver disease in this age range. However, further national multicenter studies with longitudinal design are needed for a better analysis of the correlation between nonalcoholic fatty liver disease and its risk factors, as well as its consequences. Copyright © 2018 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

MR imaging of magnetic ink patterns via off-resonance sensitivity.

PubMed

Perkins, Stephanie L; Daniel, Bruce L; Hargreaves, Brian A

2018-03-30

Printed magnetic ink creates predictable B 0 field perturbations based on printed shape and magnetic susceptibility. This can be exploited for contrast in MR imaging techniques that are sensitized to off-resonance. The purpose of this work was to characterize the susceptibility variations of magnetic ink and demonstrate its application for creating MR-visible skin markings. The magnetic susceptibility of the ink was estimated by comparing acquired and simulated B 0 field maps of a custom-built phantom. The phantom was also imaged using a 3D gradient echo sequence with a presaturation pulse tuned to different frequencies, which adjusts the range of suppressed frequencies. Healthy volunteers with a magnetic ink pattern pressed to the skin or magnetic ink temporary flexible adhesives applied to the skin were similarly imaged. The volume-average magnetic susceptibility of the ink was estimated to be 131 ± 3 parts per million across a 1-mm isotropic voxel (13,100 parts per million assuming a 10-μm thickness of printed ink). Adjusting the saturation frequency highlights different off-resonant regions created by the ink patterns; for example, if tuned to suppress fat, fat suppression will fail near the ink due to the off-resonance. This causes magnetic ink skin markings placed over a region with underlying subcutaneous fat to be visible on MR images. Patterns printed with magnetic ink can be imaged and identified with MRI. Temporary flexible skin adhesives printed with magnetic ink have the potential to be used as skin markings that are visible both by eye and on MR images. © 2018 International Society for Magnetic Resonance in Medicine.

Computer simulation of magnetic resonance spectra employing homotopy.

PubMed

Gates, K E; Griffin, M; Hanson, G R; Burrage, K

1998-11-01

Multidimensional homotopy provides an efficient method for accurately tracing energy levels and hence transitions in the presence of energy level anticrossings and looping transitions. Herein we describe the application and implementation of homotopy to the analysis of continuous wave electron paramagnetic resonance spectra. The method can also be applied to electron nuclear double resonance, electron spin echo envelope modulation, solid-state nuclear magnetic resonance, and nuclear quadrupole resonance spectra. Copyright 1998 Academic Press.

Fast 3D magnetic resonance fingerprinting for a whole-brain coverage.

PubMed

Ma, Dan; Jiang, Yun; Chen, Yong; McGivney, Debra; Mehta, Bhairav; Gulani, Vikas; Griswold, Mark

2018-04-01

The purpose of this study was to accelerate the acquisition and reconstruction time of 3D magnetic resonance fingerprinting scans. A 3D magnetic resonance fingerprinting scan was accelerated by using a single-shot spiral trajectory with an undersampling factor of 48 in the x-y plane, and an interleaved sampling pattern with an undersampling factor of 3 through plane. Further acceleration came from reducing the waiting time between neighboring partitions. The reconstruction time was accelerated by applying singular value decomposition compression in k-space. Finally, a 3D premeasured B 1 map was used to correct for the B 1 inhomogeneity. The T 1 and T 2 values of the International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology MRI phantom showed a good agreement with the standard values, with an average concordance correlation coefficient of 0.99, and coefficient of variation of 7% in the repeatability scans. The results from in vivo scans also showed high image quality in both transverse and coronal views. This study applied a fast acquisition scheme for a fully quantitative 3D magnetic resonance fingerprinting scan with a total acceleration factor of 144 as compared with the Nyquist rate, such that 3D T 1 , T 2 , and proton density maps can be acquired with whole-brain coverage at clinical resolution in less than 5 min. Magn Reson Med 79:2190-2197, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Impact of magnetic resonance imaging on preoperative planning for breast cancer surgery.

PubMed

Law, Y; Cheung, Polly S Y; Lau, Silvia; Lo, Gladys G

2013-08-01

To review the impact of preoperative breast magnetic resonance imaging on the management of planned surgery, and the appropriateness of any resulting alterations. Retrospective review. A private hospital in Hong Kong. PATIENTS; For the 147 consecutive biopsy-proven breast cancer patients who underwent preoperative magnetic resonance imaging to determine tumour extent undergoing operation by a single surgeon between 1 January 2006 and 31 December 2009, the impact of magnetic resonance imaging findings was reviewed in terms of management alterations and their appropriateness. The most common indication for breast magnetic resonance imaging was the presence of multiple indeterminate shadows on ultrasound scans (53%), followed by ill-defined border of the main tumour on ultrasound scans (19%). In 66% (97 out of 147) of the patients, the extent of the operation was upgraded. Upgrading entailed: lumpectomy to wider lumpectomy (23 out of 97), lumpectomy to mastectomy (47 out of 97), lumpectomy to bilateral lumpectomy (15 out of 97), and other (12 out of 97). Mostly, these management changes were because magnetic resonance imaging showed more extensive disease (n=29), additional cancer foci (n=39), or contralateral disease (n=24). In five instances, upgrading was due to patient preference. In 34% (50 out of 147) of the patients, there was no change in the planned operation. Regarding 97 of the patients having altered management, in 12 the changes were considered inappropriately extensive (due to false-positive magnetic resonance imaging findings). In terms of magnetic resonance imaging detection of more extensive, multifocal, multicentric, or contralateral disease, the false-positive rate was 13% and false-negative rate 7%. Corresponding rates for sensitivity and specificity were 95% and 81%, using the final pathology as the gold standard. Preoperative magnetic resonance imaging had a clinically significant and mostly correct impact on management plans. Magnetic resonance

Investigation of laser polarized xenon magnetic resonance

NASA Technical Reports Server (NTRS)

Walsworth, Ronald L.

1998-01-01

Ground-based investigations of a new biomedical diagnostic technology: nuclear magnetic resonance of laser polarized noble gas are addressed. The specific research tasks discussed are: (1) Development of a large-scale noble gas polarization system; (2) biomedical investigations using laser polarized noble gas in conventional (high magnetic field) NMR systems; and (3) the development and application of a low magnetic field system for laser polarized noble gas NMR.

Magnetic nanoparticles: In vivo cancer diagnosis and therapy.

PubMed

Lima-Tenório, Michele K; Pineda, Edgardo A Gómez; Ahmad, Nasir M; Fessi, Hatem; Elaissari, Abdelhamid

2015-09-30

Recently, significant research efforts have been devoted to the finding of efficient approaches in order to reduce the side effects of traditional cancer therapy and diagnosis. In this context, magnetic nanoparticles have attracted much attention because of their unique physical properties, magnetic susceptibility, biocompatibility, stability and many more relevant characteristics. Particularly, magnetic nanoparticles for in vivo biomedical applications need to fulfill special criteria with respect to size, size distribution, surface charge, biodegradability or bio-eliminability and optionally bear well selected ligands for specific targeting. In this context, many routes have been developed to synthesize these materials, and tune their functionalities through intriguing techniques including functionalization, coating and encapsulation strategies. In this review article, the use of magnetic nanoparticles for cancer therapy and diagnosis is evaluated addressing potential applications in MRI, drug delivery, hyperthermia, theranostics and several other domains. In view of potential biomedical applications of magnetic nanoparticles, the review focuses on the most recent progress made with respect to synthetic routes to produce magnetic nanoparticles and their salient accomplishments for in vivo cancer diagnosis and therapy. Copyright © 2015 Elsevier B.V. All rights reserved.

Rotating-frame gradient fields for magnetic resonance imaging and nuclear magnetic resonance in low fields

DOEpatents

Bouchard, Louis-Serge; Pines, Alexander; Demas, Vasiliki

2014-01-21

A system and method for Fourier encoding a nuclear magnetic resonance (NMR) signal is disclosed. A static magnetic field B.sub.0 is provided along a first direction. An NMR signal from the sample is Fourier encoded by applying a rotating-frame gradient field B.sub.G superimposed on the B.sub.0, where the B.sub.G comprises a vector component rotating in a plane perpendicular to the first direction at an angular frequency .omega.in a laboratory frame. The Fourier-encoded NMR signal is detected.

Rotatable Small Permanent Magnet Array for Ultra-Low Field Nuclear Magnetic Resonance Instrumentation: A Concept Study

PubMed Central

Vegh, Viktor; Reutens, David C.

2016-01-01

Object We studied the feasibility of generating the variable magnetic fields required for ultra-low field nuclear magnetic resonance relaxometry with dynamically adjustable permanent magnets. Our motivation was to substitute traditional electromagnets by distributed permanent magnets, increasing system portability. Materials and Methods The finite element method (COMSOL®) was employed for the numerical study of a small permanent magnet array to calculate achievable magnetic field strength, homogeneity, switching time and magnetic forces. A manually operated prototype was simulated and constructed to validate the numerical approach and to verify the generated magnetic field. Results A concentric small permanent magnet array can be used to generate strong sample pre-polarisation and variable measurement fields for ultra-low field relaxometry via simple prescribed magnet rotations. Using the array, it is possible to achieve a pre-polarisation field strength above 100 mT and variable measurement fields ranging from 20–50 μT with 200 ppm absolute field homogeneity within a field-of-view of 5 x 5 x 5 cubic centimetres. Conclusions A dynamic small permanent magnet array can generate multiple highly homogeneous magnetic fields required in ultra-low field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) instruments. This design can significantly reduce the volume and energy requirements of traditional systems based on electromagnets, improving portability considerably. PMID:27271886

Resonant Raman scattering from silicon nanoparticles enhanced by magnetic response.

PubMed

Dmitriev, Pavel A; Baranov, Denis G; Milichko, Valentin A; Makarov, Sergey V; Mukhin, Ivan S; Samusev, Anton K; Krasnok, Alexander E; Belov, Pavel A; Kivshar, Yuri S

2016-05-05

Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have a much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of the Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions.

Use of Cardiac Magnetic Resonance Imaging Based Measurements of Inferior Vena Cava Cross-Sectional Area in the Diagnosis of Pericardial Constriction.

PubMed

Hanneman, Kate; Thavendiranathan, Paaladinesh; Nguyen, Elsie T; Moshonov, Hadas; Wald, Rachel; Connelly, Kim A; Paul, Narinder S; Wintersperger, Bernd J; Crean, Andrew M

2015-08-01

To evaluate the value of cardiac magnetic resonance imaging (MRI)-based measurements of inferior vena cava (IVC) cross-sectional area in the diagnosis of pericardial constriction. Patients who had undergone cardiac MRI for evaluation of clinically suspected pericardial constriction were identified retrospectively. The diagnosis of pericardial constriction was established by clinical history, echocardiography, cardiac catheterization, intraoperative findings, and/or histopathology. Cross-sectional areas of the suprahepatic IVC and descending aorta were measured on a single axial steady-state free-precession (SSFP) image at the level of the esophageal hiatus in end-systole. Logistic regression and receiver-operating curve (ROC) analyses were performed. Thirty-six patients were included; 50% (n = 18) had pericardial constriction. Mean age was 53.9 ± 15.3 years, and 72% (n = 26) were male. IVC area, ratio of IVC to aortic area, pericardial thickness, and presence of respirophasic septal shift were all significantly different between patients with constriction and those without (P < .001 for all). IVC to aortic area ratio had the highest odds ratio for the prediction of constriction (1070, 95% confidence interval [8.0-143051], P = .005). ROC analysis illustrated that IVC to aortic area ratio discriminated between those with and without constriction with an area under the curve of 0.96 (95% confidence interval [0.91-1.00]). In patients referred for cardiac MRI assessment of suspected pericardial constriction, measurement of suprahepatic IVC cross-sectional area may be useful in confirming the diagnosis of constriction when used in combination with other imaging findings, including pericardial thickness and respirophasic septal shift. Copyright © 2015 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Pulse Coupled Neural Networks for the Segmentation of Magnetic Resonance Brain Images.

DTIC Science & Technology

1996-12-01

PULSE COUPLED NEURAL NETWORKS FOR THE SEGMENTATION OF MAGNETIC RESONANCE BRAIN IMAGES THESIS Shane Lee Abrahamson First Lieutenant, USAF AFIT/GCS/ENG...COUPLED NEURAL NETWORKS FOR THE SEGMENTATION OF MAGNETIC RESONANCE BRAIN IMAGES THESIS Shane Lee Abrahamson First Lieutenant, USAF AFIT/GCS/ENG/96D-01...research develops an automated method for segmenting Magnetic Resonance (MR) brain images based on Pulse Coupled Neural Networks (PCNN). MR brain image

Serial Magnetic Resonance Imaging in Active Surveillance of Prostate Cancer: Incremental Value.

PubMed

Felker, Ely R; Wu, Jason; Natarajan, Shyam; Margolis, Daniel J; Raman, Steven S; Huang, Jiaoti; Dorey, Fred; Marks, Leonard S

2016-05-01

We assessed whether changes in serial multiparametric magnetic resonance imaging can help predict the pathological progression of prostate cancer in men on active surveillance. A retrospective cohort study was conducted of 49 consecutive men with Gleason 6 prostate cancer who underwent multiparametric magnetic resonance imaging at baseline and again more than 6 months later, each followed by a targeted prostate biopsy, between January 2011 and May 2015. We evaluated whether progression on multiparametric magnetic resonance imaging (an increase in index lesion suspicion score, increase in index lesion volume or decrease in index lesion apparent diffusion coefficient) could predict pathological progression (Gleason 3 + 4 or greater on subsequent biopsy, in systematic or targeted cores). Diagnostic performance of multiparametric magnetic resonance imaging was determined with and without clinical data using a binary logistic regression model. The mean interval between baseline and followup multiparametric magnetic resonance imaging was 28.3 months (range 11 to 43). Pathological progression occurred in 19 patients (39%). The sensitivity, specificity, positive predictive value and negative predictive value of multiparametric magnetic resonance imaging was 37%, 90%, 69% and 70%, respectively. Area under the receiver operating characteristic curve was 0.63. A logistic regression model using clinical information (maximum cancer core length greater than 3 mm on baseline biopsy or a prostate specific antigen density greater than 0.15 ng/ml(2) at followup biopsy) had an AUC of 0.87 for predicting pathological progression. The addition of serial multiparametric magnetic resonance imaging data significantly improved the AUC to 0.91 (p=0.044). Serial multiparametric magnetic resonance imaging adds incremental value to prostate specific antigen density and baseline cancer core length for predicting Gleason 6 upgrading in men on active surveillance. Copyright © 2016

Transcranial magnetic stimulation assisted by neuronavigation of magnetic resonance images

NASA Astrophysics Data System (ADS)

Viesca, N. Angeline; Alcauter, S. Sarael; Barrios, A. Fernando; González, O. Jorge J.; Márquez, F. Jorge A.

2012-10-01

Technological advance has improved the way scientists and doctors can learn about the brain and treat different disorders. A non-invasive method used for this is Transcranial Magnetic Stimulation (TMS) based on neuron excitation by electromagnetic induction. Combining this method with functional Magnetic Resonance Images (fMRI), it is intended to improve the localization technique of cortical brain structures by designing an extracranial localization system, based on Alcauter et al. work.

Magnetic Resonance Imaging as a Predictor of Survival Free of Life-Threatening Arrhythmias and Transplantation in Cardiac Sarcoidosis.

PubMed

Ekström, Kaj; Lehtonen, Jukka; Hänninen, Helena; Kandolin, Riina; Kivistö, Sari; Kupari, Markku

2016-05-02

Cardiac magnetic resonance imaging has a key role in today's diagnosis of cardiac sarcoidosis. We set out to investigate whether cardiac magnetic resonance imaging also helps predict outcome in cardiac sarcoidosis. Our work involved 59 patients with cardiac sarcoidosis (38 female, mean age 46±10 years) seen at our hospital since February 2004 and followed up after contrast-enhanced cardiac magnetic resonance imaging. The extent of myocardial late gadolinium enhancement (measured as percentage of left ventricular mass), the volumes and ejection fractions of the left and right ventricles, and the thickness of the basal interventricular septum were determined and analyzed for prognostic significance. By April 2015, 23 patients had reached the study's end point, consisting of a composite of cardiac death (n=3), cardiac transplantation (n=1), and occurrence of life-threatening ventricular tachyarrhythmias (n=19; ventricular fibrillation in 5 and sustained ventricular tachycardia in 14 patients). In univariate analysis, myocardial extent of late gadolinium enhancement predicted event-free survival, as did scar-like thinning (<4 mm) of the basal interventricular septum and the ejection fraction of the right ventricle (P<0.05 for all). In multivariate Cox regression analysis, extent of late gadolinium enhancement was the only independent predictor of outcome events on cardiac magnetic resonance imaging, with a hazard ratio of 2.22 per tertile (95% CI 1.07-4.59). An extent of late gadolinium enhancement >22% (third tertile) had positive and negative predictive values for serious cardiac events of 75% and 76%, respectively. Findings on cardiac magnetic resonance imaging and the extent of myocardial late gadolinium enhancement in particular help predict serious cardiac events in cardiac sarcoidosis. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Force-detected nuclear magnetic resonance: recent advances and future challenges.

PubMed

Poggio, M; Degen, C L

2010-08-27

We review recent efforts to detect small numbers of nuclear spins using magnetic resonance force microscopy. Magnetic resonance force microscopy (MRFM) is a scanning probe technique that relies on the mechanical measurement of the weak magnetic force between a microscopic magnet and the magnetic moments in a sample. Spurred by the recent progress in fabricating ultrasensitive force detectors, MRFM has rapidly improved its capability over the last decade. Today it boasts a spin sensitivity that surpasses conventional, inductive nuclear magnetic resonance detectors by about eight orders of magnitude. In this review we touch on the origins of this technique and focus on its recent application to nanoscale nuclear spin ensembles, in particular on the imaging of nanoscale objects with a three-dimensional (3D) spatial resolution better than 10 nm. We consider the experimental advances driving this work and highlight the underlying physical principles and limitations of the method. Finally, we discuss the challenges that must be met in order to advance the technique towards single nuclear spin sensitivity-and perhaps-to 3D microscopy of molecules with atomic resolution.

Dobutamine stress magnetic resonance imaging: a valuable method in the noninvasive diagnosis of ischemic heart disease.

PubMed

van Dijkman, Paul R M; Kuijpers, Dirkjan A; Blom, Bernadette M; van Herpen, Gerard

2002-01-01

We assessed the clinical applicability of dobutamine stress magnetic resonance imaging (DS-MRI) for the detection of myocardial ischemia and myocardial viability. One hundred patients with suspected coronary artery disease and inconclusive exercise electrocardiography or significant repolarization abnormalities on the resting ECG underwent breath hold DS-MRI (1 Tesla), 4 days after cessation of anti-ischemic medication. Three left ventricular short axis planes were imaged at increasing doses of dobutamine. Recovery of wall thickening in a previously diminished or non contracting segment at low dose dobutamine was considered proof of viability. Development of hypo-, a- or dyskinesia at higher doses of dobutamine was taken to indicate ischemia. If the DS-MRI test was positive for ischemia, coronary angiography was performed. If indicated, this was followed by revascularization. If DS-MRI did not demonstrate ischemia, neither angiography nor revascularization were carried out. Ninety five DS-MRI investigations were available for diagnosis. Forty two patients had DS-MRI scans positive for ischemia and subsequently coronary angiography assessment of the clinical applicability of DS-MRI for the detection of myocardial ischemia was performed. One patient was false-positive. All 53 patients with non-ischemic DS-MRI scans had follow-up for 11-23 months (mean 17 months). One patient died suddenly 2 weeks after the MRI-test. The other 52 patients did not experience any coronary event nor sudden cardiac death. The predictive value of a positive (for ischemia) DS-MRI test is 98% and the predictive value of a negative DS-MRI test is also 98%.

Magnetic resonance imaging of articular cartilage: trauma, degeneration, and repair.

PubMed

Potter, Hollis G; Foo, Li F

2006-04-01

The assessment of articular cartilage using magnetic resonance imaging has seen considerable advances in recent years. Cartilage morphologic characteristics can now be evaluated with a high degree of accuracy and reproducibility using dedicated pulse sequences, which are becoming standard at many institutions. These techniques detect clinically unsuspected traumatic cartilage lesions, allowing the physician to study their natural history with longitudinal evaluation and also to assess disease status in degenerative osteoarthritis. Magnetic resonance imaging also provides a more objective assessment of cartilage repair to augment the information obtained from more subjective clinical outcome instruments. Newly developed methods that provide detail at an ultrastructural level offer an important addition to cartilage evaluation, particularly in the detection of early alterations in the extracellular matrix. These methods have created an undeniably important role for magnetic resonance imaging in the reproducible, noninvasive, and objective evaluation and monitoring of cartilage. An overview of the advances, current techniques, and impact of magnetic resonance imaging in the setting of trauma, degenerative arthritides, and surgical treatment for cartilage injury is presented.

Observation of resonant and non-resonant magnetic braking in the n = 1 non-axisymmetric configurations on KSTAR

NASA Astrophysics Data System (ADS)

Kim, Kimin; Choe, W.; In, Y.; Ko, W. H.; Choi, M. J.; Bak, J. G.; Kim, H. S.; Jeon, Y. M.; Kwak, J. G.; Yoon, S. W.; Oh, Y. K.; Park, J.-K.

2017-12-01

Toroidal rotation braking by neoclassical toroidal viscosity driven by non-axisymmetric (3D) magnetic fields, called magnetic braking, has great potential to control rotation profile, and thereby modify tokamak stability and performance. In order to characterize magnetic braking in the various 3D field configurations, dedicated experiments have been carried out in KSTAR, applying a variety of static n=1 , 3D fields of different phasing of -90 , 0, and +90 . Resonant-type magnetic braking was achieved by -90 phasing fields, accompanied by strong density pump-out and confinement degradation, and explained by excitation of kink response captured by ideal plasma response calculation. Strong resonant plasma response was also observed under +90 phasing at q95 ∼ 6 , leading to severe confinement degradation and eventual disruption by locked modes. Such a strong resonant transport was substantially modified to non-resonant-type transport at higher q95 ∼ 7.2 , as the resonant particle transport was significantly reduced and the rotation braking was pushed to plasma edge. This is well explained by ideal perturbed equilibrium calculations indicating the strong kink coupling at lower q95 is reduced at higher q95 discharge. The 0 phasing fields achieved quiescent magnetic braking without density pump-out and confinement degradation, which is consistent with vacuum and ideal plasma response analysis predicting deeply penetrating 3D fields without an excitation of strong kink response.

Nuclear magnetic resonance properties of lunar samples.

NASA Technical Reports Server (NTRS)

Kline, D.; Weeks, R. A.

1972-01-01

Nuclear magnetic resonance spectra of Na-23, Al-27, and P-31 in fines samples 10084,60 and 14163,168 and in crystalline rock samples 12021,55 and 14321,166, have been recorded over a range of frequencies up to 20 MHz. A shift in the field at which maximum absorption occurs for all of the spectra relative to the field at which maximum absorption occurs for terrestrial analogues is attributed to a sample-dependent magnetic field at the Na, Al, and P sites opposing the laboratory field. The magnitude of these fields internal to the samples is sample dependent and varies from 5 to 10 G. These fields do not correlate with the iron content of the samples. However, the presence of single-domain particles of iron distributed throughout the plagioclase fraction that contains the principal fraction of Na and Al is inferred from electron magnetic resonance spectra shapes.

Image Guided Focal Therapy for Magnetic Resonance Imaging Visible Prostate Cancer: Defining a 3-Dimensional Treatment Margin Based on Magnetic Resonance Imaging Histology Co-Registration Analysis.

PubMed

Le Nobin, Julien; Rosenkrantz, Andrew B; Villers, Arnauld; Orczyk, Clément; Deng, Fang-Ming; Melamed, Jonathan; Mikheev, Artem; Rusinek, Henry; Taneja, Samir S

2015-08-01

We compared prostate tumor boundaries on magnetic resonance imaging and radical prostatectomy histological assessment using detailed software assisted co-registration to define an optimal treatment margin for achieving complete tumor destruction during image guided focal ablation. Included in study were 33 patients who underwent 3 Tesla magnetic resonance imaging before radical prostatectomy. A radiologist traced lesion borders on magnetic resonance imaging and assigned a suspicion score of 2 to 5. Three-dimensional reconstructions were created from high resolution digitalized slides of radical prostatectomy specimens and co-registered to imaging using advanced software. Tumors were compared between histology and imaging by the Hausdorff distance and stratified by the magnetic resonance imaging suspicion score, Gleason score and lesion diameter. Cylindrical volume estimates of treatment effects were used to define the optimal treatment margin. Three-dimensional software based registration with magnetic resonance imaging was done in 46 histologically confirmed cancers. Imaging underestimated tumor size with a maximal discrepancy between imaging and histological boundaries for a given tumor of an average ± SD of 1.99 ± 3.1 mm, representing 18.5% of the diameter on imaging. Boundary underestimation was larger for lesions with an imaging suspicion score 4 or greater (mean 3.49 ± 2.1 mm, p <0.001) and a Gleason score of 7 or greater (mean 2.48 ± 2.8 mm, p = 0.035). A simulated cylindrical treatment volume based on the imaging boundary missed an average 14.8% of tumor volume compared to that based on the histological boundary. A simulated treatment volume based on a 9 mm treatment margin achieved complete histological tumor destruction in 100% of patients. Magnetic resonance imaging underestimates histologically determined tumor boundaries, especially for lesions with a high imaging suspicion score and a high Gleason score. A 9 mm treatment margin around a lesion

Gadolinium-enhanced magnetic resonance angiography in renal artery stenosis: comparison with digital subtraction angiography.

PubMed

Law, Y M; Tay, K H; Gan, Y U; Cheah, F K; Tan, B S

2008-04-01

To evaluate the accuracy of gadolinium-enhanced magnetic resonance angiography in assessing renal artery stenosis compared to catheter digital subtraction angiography. Retrospective study. Singapore General Hospital. Records of patients who underwent magnetic resonance angiography as well as digital subtraction angiography for assessment of renal artery stenosis from January 2003 to December 2005 were reviewed. There were 27 patients (14 male, 13 female) with a mean age of 62 (range, 44-77) years. There were 10 patients with renal transplants; their native renal arteries were not evaluated. Each of the two experienced interventional and body magnetic resonance radiologists, who were blinded to the results, reviewed the digital subtraction angiography and magnetic resonance angiography images respectively. Digital subtraction angiography was used as the standard of reference. A total of 39 renal arteries from these 27 patients were evaluated. One of the arteries was previously stented and could not be assessed with magnetic resonance angiography due to severe artefacts. Of the remaining 38 renal arteries, two were graded as normal, seven as having mild stenosis (<50%), eight as having moderate stenosis (> or =50% but <75%), and 21 as having severe stenosis (> or =75%). Magnetic resonance angiography and digital subtraction angiography were concordant in 89% of the arteries; magnetic resonance angiography overestimated the degree of stenosis in 8% and underestimated it in 3% of them. In the evaluation of clinically significant renal artery stenosis (> or =50%) with magnetic resonance angiography, the overall sensitivity, specificity, positive predictive value, and negative predictive value were 97%, 67%, 90%, and 86% respectively. The sensitivity and specificity of magnetic resonance angiography in transplant renal artery stenosis was 100%. CONCLUSION. Our experience suggested that gadolinium-enhanced magnetic resonance angiography is a sensitive non

Magnetic resonance elastography (MRE) of the human brain: technique, findings and clinical applications

NASA Astrophysics Data System (ADS)

Hiscox, Lucy V.; Johnson, Curtis L.; Barnhill, Eric; McGarry, Matt D. J.; Huston 3rd, John; van Beek, Edwin J. R.; Starr, John M.; Roberts, Neil

2016-12-01

Neurological disorders are one of the most important public health concerns in developed countries. Established brain imaging techniques such as magnetic resonance imaging (MRI) and x-ray computerised tomography (CT) have been essential in the identification and diagnosis of a wide range of disorders, although usually are insufficient in sensitivity for detecting subtle pathological alterations to the brain prior to the onset of clinical symptoms—at a time when prognosis for treatment is more favourable. The mechanical properties of biological tissue provide information related to the strength and integrity of the cellular microstructure. In recent years, mechanical properties of the brain have been visualised and measured non-invasively with magnetic resonance elastography (MRE), a particularly sensitive medical imaging technique that may increase the potential for early diagnosis. This review begins with an introduction to the various methods used for the acquisition and analysis of MRE data. A systematic literature search is then conducted to identify studies that have specifically utilised MRE to investigate the human brain. Through the conversion of MRE-derived measurements to shear stiffness (kPa) and, where possible, the loss tangent (rad), a summary of results for global brain tissue and grey and white matter across studies is provided for healthy participants, as potential baseline values to be used in future clinical investigations. In addition, the extent to which MRE has revealed significant alterations to the brain in patients with neurological disorders is assessed and discussed in terms of known pathophysiology. The review concludes by predicting the trends for future MRE research and applications in neuroscience.

Diffusion Magnetic Resonance Imaging: What Water Tells Us about Biological Tissues

PubMed Central

Le Bihan, Denis; Iima, Mami

2015-01-01

Since its introduction in the mid-1980s, diffusion magnetic resonance imaging (MRI), which measures the random motion of water molecules in tissues, revealing their microarchitecture, has become a pillar of modern neuroimaging. Its main clinical domain has been the diagnosis of acute brain stroke and neurogical disorders, but it is also used in the body for the detection and management of cancer lesions. It can also produce stunning maps of white matter tracks in the brain, with the potential to aid in the understanding of some psychiatric disorders. However, in order to exploit fully the potential of this method, a deeper understanding of the mechanisms that govern the diffusion of water in tissues is needed. PMID:26204162

Magnetic resonances in perovskite-type layer structures

NASA Astrophysics Data System (ADS)

Strobel, K.; Geick, R.

1981-08-01

We have studied the q=0 magnetic excitations of the perovskite-type layer structures A 2MnCl 4 with A=Rb, C nH 2n+1NH 3 (n=1,2,3), and NH 3(CH 2) mNH 3MnCl 4 (m=2,4,5) in the antiferromagnetic and in the spin flop regime by means of magnetic resonance in the mm-wave range (30-130GHz) and microwave range (9.2GHz). The length of the organic molecules determines the separation of the MnCl 6 octahedra. With increasing separation the Néel temperature and the antiferromagnetic resonance frequency decrease, which mainly originates from a decrease of the anisotropy field.

Diffusion weighted imaging with background body signal suppression / T2 image fusion in magnetic resonance mammography for breast cancer diagnosis.

PubMed

Nechifor-Boilă, I A; Bancu, S; Buruian, M; Charlot, M; Decaussin-Petrucci, M; Krauth, J-S; Nechifor-Boilă, A C; Borda, A

2013-01-01

Dynamic Contrast-Enhanced Magnetic Resonance Mammography (DCE-MRM) represents the most sensitive examination for breast cancer (BC) diagnosis. However literature data reports very inhomogeneous specificity. The aim of our study was to evaluate the clinical efficiency of a new MRM technique - diffusion weighted imaging with background body signal suppression T2 image fusion in BC diagnosis, compared to DCE-MRM. We retrospectively analyzed 50 consecutive DCE-MRM examinations with DWIBS sequence from the archives of the Department of Radiology, Lyon Sud Hospital, (02.2010- 02.2011), summing up to 64 breast lesions. Fusions were created using the Osirix software from the DWIBS images (b=1000 s mm2) and their T2 correspondents. Interpretation was performed using an adapted BI-RADS system. The final histopathological examination or a minimum 6-months follow-up served as gold standard. Out of the 64 examined breast lesions, 35(54.7%) were classified as malignant by DCE-MRM and 24(37.5%) cases by DWIBS T2, respectively. Thus the DWIBS T2 fusion had a Sensitivity of 62.5%(95%CI:35.4-84.8) and a Specificity of 70.8%(95%CI:55.9-83.3) while DCE-MRM had a higher Sensitivity: 87.5%(95%CI:61.6-98.4) but a lower Specificity: 56.2%(95%CI:41.1-70.5). DWIBS T2 fusion is an innovative MRM technique, with a specificity superior to DCE-MRM, showing a large potential for improving the clinical efficiency of classical MRM. Celsius.

Detecting prostate cancer and prostatic calcifications using advanced magnetic resonance imaging.

PubMed

Dou, Shewei; Bai, Yan; Shandil, Ankit; Ding, Degang; Shi, Dapeng; Haacke, E Mark; Wang, Meiyun

2017-01-01

Prostate cancer and prostatic calcifications have a high incidence in elderly men. We aimed to investigate the diagnostic capabilities of susceptibility-weighted imaging in detecting prostate cancer and prostatic calcifications. A total number of 156 men, including 34 with prostate cancer and 122 with benign prostate were enrolled in this study. Computed tomography, conventional magnetic resonance imaging, diffusion-weighted imaging, and susceptibility-weighted imaging were performed on all the patients. One hundred and twelve prostatic calcifications were detected in 87 patients. The sensitivities and specificities of the conventional magnetic resonance imaging, apparent diffusion coefficient, and susceptibility-filtered phase images in detecting prostate cancer and prostatic calcifications were calculated. McNemar's Chi-square test was used to compare the differences in sensitivities and specificities between the techniques. The results showed that the sensitivity and specificity of susceptibility-filtered phase images in detecting prostatic cancer were greater than that of conventional magnetic resonance imaging and apparent diffusion coefficient (P < 0.05). In addition, the sensitivity and specificity of susceptibility-filtered phase images in detecting prostatic calcifications were comparable to that of computed tomography and greater than that of conventional magnetic resonance imaging and apparent diffusion coefficient (P < 0.05). Given the high incidence of susceptibility-weighted imaging (SWI) abnormality in prostate cancer, we conclude that susceptibility-weighted imaging is more sensitive and specific than conventional magnetic resonance imaging, diffusion-weighted imaging, and computed tomography in detecting prostate cancer. Furthermore, susceptibility-weighted imaging can identify prostatic calcifications similar to computed tomography, and it is much better than conventional magnetic resonance imaging and diffusion-weighted imaging.

Endometrioid adenocarcinoma arising in adenomyosis: elucidation by periodic magnetic resonance imaging evaluations.

PubMed

Motohara, Kenichi; Tashiro, Hironori; Ohtake, Hideyuki; Saito, Fumitaka; Ohba, Takashi; Katabuchi, Hidetaka

2008-06-01

There are several case reports of adenocarcinomas developing within adenomyosis. However, there is no report demonstrating the natural course from adenomyosis to adenocarcinoma. We report a patient (a 41-year-old Japanese woman) who was observed every 6 months after being diagnosed with adenomyosis at our University Hospital. Although she went through menopause at age 51, she occasionally complained subsequently of abnormal genital bleeding. Eleven years after the initial diagnosis, endometrial cytology revealed the presence of malignant cells. Pelvic magnetic resonance imaging (MRI) demonstrated replacement of the adenomyotic lesion by a poorly demarcated lesion, compared to the findings on prior MRI. Consequently, we performed a modified radical hysterectomy and pelvic lymph node dissection, under a presumptive diagnosis of adenocarcinoma arising in adenomyosis. Histological diagnosis revealed an endometrioid adenocarcinoma (G3) transformed from adenomyotic epithelium, which was classified, according to the International Federation of Gynecology and Obstetrics, as stage Ic, pT1cN0M0. In this patient, periodic MRI evaluations, in conjunction with pathological examination, identified the transformation from adenomyosis to adenocarcinoma.

Magnetic Resonance Spectroscopy: An In Vivo Molecular Imaging Biomarker for Parkinson's Disease?

PubMed Central

Ciurleo, Rosella; Di Lorenzo, Giuseppe; Marino, Silvia

2014-01-01

Parkinson's disease (PD) is a neurodegenerative disorder caused by selective loss of dopaminergic neurons in the substantia nigra pars compacta which leads to dysfunction of cerebral pathways critical for the control of movements. The diagnosis of PD is based on motor symptoms, such as bradykinesia, akinesia, muscular rigidity, postural instability, and resting tremor, which are evident only after the degeneration of a significant number of dopaminergic neurons. Currently, a marker for early diagnosis of PD is still not available. Consequently, also the development of disease-modifying therapies is a challenge. Magnetic resonance spectroscopy is a quantitative imaging technique that allows in vivo measurement of certain neurometabolites and may produce biomarkers that reflect metabolic dysfunctions and irreversible neuronal damage. This review summarizes the abnormalities of cerebral metabolites found in MRS studies performed in patients with PD and other forms of parkinsonism. In addition, we discuss the potential role of MRS as in vivo molecular imaging biomarker for early diagnosis of PD and for monitoring the efficacy of therapeutic interventions. PMID:25302300

Intraoperative Magnetic Resonance Imaging-Guided Biopsy in the Diagnosis of Suprasellar Langerhans Cell Histiocytosis.

PubMed

Carroll, Kate T; Lochte, Bryson C; Chen, James Y; Snyder, Vivian S; Carter, Bob S; Chen, Clark C

2018-04-01

Magnetic resonance imaging (MRI)-guided biopsy is an emerging diagnostic technique that holds great promise for otherwise difficult to access neuroanatomy. Here we describe MRI-guided biopsy of a suprasellar lesion located posterior and superior to the pituitary stalk. The approach was implemented successfully in a 38-year-old woman who had developed progressive visual deterioration. Intraoperative MRI revealed the need for trajectory adjustment due to an unintended, minor deviation in the burr hole entry point, demonstrating the benefit of an MRI-guided approach. Langerhans cell histiocytosis was diagnosed after biopsy, and the lesion regressed after cladribine treatment. Technical nuances of the case are reviewed in the context of the available literature. Copyright © 2018 Elsevier Inc. All rights reserved.

Sublingual epidermoid cyst presenting with distinctive magnetic resonance imaging findings.

PubMed

Yoshida, Naohiro; Kodama, Kozue; Iino, Yukiko

2014-06-18

A case of sublingual epidermoid cyst presenting distinctive magnetic resonance imaging (MRI) findings is described. A 39-year-old man presented to our hospital with a three months progressive left submandibular swelling, difficulty moving his tongue, and snoring. Preoperative evaluation with MRI and fine needle aspiration cytology (FNAC) revealed that the heterogeneous cystic lesion contained the squamous cells, which is compatible with ectodermal tissue. The mass was located above the mylohyoid muscle and spread to the pharyngeal space. By considering the size, infection history, patient age, and location, the cyst was completely resected under general anesthesia via cervical approach without any complication. Histopathologically, the cyst wall was lined by stratified squamous epithelium with no skin appendage, suggesting an epidermoid cyst. Ultrasound (US), MRI and FNAC were very useful of the preoperative diagnosis for oral and sublingual lesion. The postoperative course was uneventful and without recurrence after 24 months. This case showed that epidermoid cysts formed the rarely heterogeneous cystic tumor and it underlined usefulness of preoperative diagnosis, such as US, MRI and FNAC for oral and sublingual tumor.

Magnetic resonance imaging findings in the evaluation of traumatic anosmia.

PubMed

Wise, Jeffrey B; Moonis, Gul; Mirza, Natasha

2006-02-01

Head trauma is a common cause of anosmia, but diagnosis is typically late, owing to more life-threatening sequelae of the injury. Herein, we describe our workup for a case of traumatic anosmia and the magnetic resonance imaging (MRI) findings both at the time of injury and at the 18-month follow-up. We present a case report and a review of the literature. A 33-year-old woman presented to our institution with a chief complaint of loss of smell and taste following an occipital blow to her head that occurred when she was hit by a car while riding a bicycle. We present the findings of MRI performed at the time of the injury and at the 18-month follow-up. We describe the clinical progression of her disease, from symptoms of parosmic and phantosmic episodes accompanied by dysgeusia to total anosmia at the 18-month follow-up. We advocate the use of MRI, coupled with otolaryngology consultation and formal olfactory testing, in the diagnosis, management, and counseling of patients with anosmia sustained from head injury.

MEMS-Based Force-Detected Nuclear Magnetic Resonance (FDNMR) Spectrometer

NASA Technical Reports Server (NTRS)

Lee, Choonsup; Butler, Mark C.; Elgammal, Ramez A.; George, Thomas; Hunt, Brian; Weitekamp, Daniel P.

2006-01-01

Nuclear Magnetic Resonance (NMR) spectroscopy allows assignment of molecular structure by acquiring the energy spectrum of nuclear spins in a molecule, and by interpreting the symmetry and positions of resonance lines in the spectrum. As such, NMR has become one of the most versatile and ubiquitous spectroscopic methods. Despite these tremendous successes, NMR experiments suffer from inherent low sensitivity due to the relatively low energy of photons in the radio frequency (rt) region of the electromagnetic spectrum. Here, we describe a high-resolution spectroscopy in samples with diameters in the micron range and below. We have reported design and fabrication of force-detected nuclear magnetic resonance (FDNMR).

[Antenatal diagnosis of placenta accreta].

PubMed

Malinova, M

2014-01-01

Placenta accreta is a potentially life-threatening obstetric condition. Diagnosis of placenta accreta before delivery allows multidisciplinary planning in an attempt to minimize potential maternal or neonatal morbidity and mortality The diagnosis is usually established by 2D, 3D Ultrasonography and Color Doppler ultrasonography and occasionally supplemented by Magnetic Resonance Imaging.

Numerical study of remote detection outside the magnet with travelling wave Magnetic Resonance Imaging at 3T

NASA Astrophysics Data System (ADS)

López, M.; Vázquez, F.; Solís-Nájera, S.; Rodriguez, A. O.

2015-01-01

The use of the travelling wave approach for high magnetic field magnetic resonance imaging has been used recently with very promising results. This approach offer images one with greater field-of-view and a reasonable signal-to-noise ratio using a circular waveguide. This scheme has been proved to be successful at 7 T and 9.4 T with whole-body imager. Images have also been acquired with clinical magnetic resonance imaging systems whose resonant frequencies were 64 MHz and 128 MHz. These results motivated the use of remote detection of the magnetic resonance signal using a parallel-plate waveguide together with 3 T clinical scanners, to acquired human leg images. The cut-off frequency of this waveguide is zero for the principal mode, allowing us to overcome the barrier of transmitting waves at lower frequency than 300 MHz or 7 T for protons. These motivated the study of remote detection outside the actual magnet. We performed electromagnetic field simulations of a parallel-plate waveguide and a phantom. The signal transmission was done at 128 MHz and using a circular surface coil located almost 200 cm away for the magnet isocentre. Numerical simulations demonstrated that the magnetic field of the principal mode propagate inside a waveguide outside the magnet. Numerical results were compared with previous experimental-acquired image data under similar conditions.

Vibration-synchronized magnetic resonance imaging for the detection of myocardial elasticity changes.

PubMed

Elgeti, Thomas; Tzschätzsch, Heiko; Hirsch, Sebastian; Krefting, Dagmar; Klatt, Dieter; Niendorf, Thoralf; Braun, Jürgen; Sack, Ingolf

2012-04-01

Vibration synchronized magnetic resonance imaging of harmonically oscillating tissue interfaces is proposed for cardiac magnetic resonance elastography. The new approach exploits cardiac triggered cine imaging synchronized with extrinsic harmonic stimulation (f = 22.83 Hz) to display oscillatory tissue deformations in magnitude images. Oscillations are analyzed by intensity threshold-based image processing to track wave amplitude variations over the cardiac cycle. In agreement to literature data, results in 10 volunteers showed that endocardial wave amplitudes during systole (0.13 ± 0.07 mm) were significantly lower than during diastole (0.34 ± 0.14 mm, P < 0.001). Wave amplitudes were found to decrease 117 ± 40 ms before myocardial contraction and to increase 75 ± 31 ms before myocardial relaxation. Vibration synchronized magnetic resonance imaging improves the temporal resolution of magnetic resonance elastography as it overcomes the use of extra motion encoding gradients, is less sensitive to susceptibility artifacts, and does not suffer from dynamic range constraints frequently encountered in phase-based magnetic resonance elastography. Copyright © 2012 Wiley Periodicals, Inc.

Prognostic value of perfusion-weighted magnetic resonance imaging in acute intracerebral hemorrhage.

PubMed

Hu, Xibin; Bai, Xueqin; Zai, Ning; Sun, Xinhai; Zhu, Laimin; Li, Xian

2016-07-01

This study intends to investigate the prognostic value of perfusion-weighted magnetic resonance imaging in acute intracerebral hemorrhage. Demographic, clinical and biochemical data between acute intracerebral hemorrhage (AICH) and healthy volunteer groups were assessed in this study, such as rCBV and MTT values. The optimal cutoff values of rCBV and MTT for diagnosing AICH were determined by the ROC curves. Apart from that, we also investigated the association between rCBV/MTT values and cerebral hematoma volumes of AICH patients. The unconditional logistic regression was conducted to determine significant risk factors for AICH. AICH patients have significantly lower rCBV and higher MTT compared to the control group (all P < 0.05). As suggested by the relatively high sensitivity and specificity, both rCBV and MTT values could be utilized for AICH diagnosis. Moreover, rCBV and MTT were significantly associated with the cerebral hematoma volumes of AICH patients (all P < 0.05). Results from unconditional logistic regression analysis revealed that MTT was a significant risk factor for AICH (P < 0.05 and OR > 1), while rCBV is considered as a protective factor (P < 0.05 and OR < 1). Perfusion-weighted magnetic resonance imaging produces a high prognostic value for diagnosing AICH.

[Potentialities of low-field magnetic resonance tomography in the diagnosis and treatment of invasive cancer of cervix uteri].

PubMed

Shatov, A V

2003-01-01

The aim of the study was to evaluate the efficiency of low-field (0.14 T) magnetic resonance imaging (MRI) in the diagnosis and treatment of cancer of the cervix uteri. Low-field MRI was performed in 39 patients with cancer of the cervix uteri to define the stage of the tumor and to follow up the outcomes of their treatment. Particular emphasis was laid on the determination of the size of the tumor and the presence of parametral invasion and on metastatic lesions of lymph nodes. MRI data were compared with clinical, morphological, and surgical staging results. In detecting the stage of cancer of the cervix uteri, the accuracy of MRI was 72% whereas that of clinical study was 51%. In determining parametral invasion, the accuracy of clinical study and low-field MRI was 71 and 90%, respectively. The sensitivity and specificity of MRI were 83 and 92%, respectively. The anterioposterior tumor size was an important prognostic factor in following up the outcomes of treatment as there was its close association and the incidence of tumor recurrences. The present study has indicated that the high efficiency of low-field MRI in detecting the stage of invasive cancer of cervix uteri makes it the method of choice in planning treatment and monitoring the outcomes of combined radiation therapy.

Structural and Functional Magnetic Resonance Imaging: Mild Cognitive Impairment and Alzheimer Disease.

PubMed

Lockau, Hannah; Jessen, Frank; Fellgiebel, Andreas; Drzezga, Alexander

2013-10-01

Magnetic resonance (MR) imaging is playing an increasingly pivotal role in the clinical management of dementia, including Alzheimer disease (AD). In addition to established MR imaging procedures, the introduction of advanced instrumentation such as 7-T MR imaging, as well as novel MR imaging sequences such as arterial spin labeling, MR spectroscopy, diffusion tensor imaging, and resting-state functional MR imaging, may open new pathways toward improved diagnosis of AD even in early stages of disease such as mild cognitive impairment (MCI). This article describes the typical findings of established and new MR imaging procedures in healthy aging, MCI, and AD. Copyright © 2013 Elsevier Inc. All rights reserved.

Demonstration of a bronchobiliary fistula using magnetic resonance image with hepatospecific contrast agent.

PubMed

Baleato-González, S; Vieira-Leite, C; Alvárez-Castro, A M; García-Figueiras, R

Bronchobiliary fistulas are a rare entity of difficult diagnosis. The utility of magnetic resonance image (MRI) with hepatospecific contrast agents to demonstrate such condition is seldom described in the literature. This case reports a patient with pulmonary infection with a past history of hepatic surgery for hydatid disease in whom the presence of bile in the sputum rose the suspicious of a bronchobiliary fistula. MRI with hepatospecific contrast agents showed the communication between the biliary and bronchial tree and provided anatomic data to allow a therapeutic approach. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

Pneumatocyst, mimicking a sclerotic bony lesion on magnetic resonance imaging.

PubMed

Zarei, Fariba; Iranpour, Pooya

2010-04-01

Intravertebral pneumatocyst is an uncommon benign lesion, not related to conditions, such as osteomyelitis and postsurgical state, with only a few cases reported in the literature. The purpose of the study was to report a case of cervical pneumatocyst resembling a sclerotic lesion on magnetic resonance imaging (MRI) and review of literature. The study was designed to be a case report. The patient chosen was a 48-year-old woman with the chief complaint of neck pain and bilateral upper extremity paresthesia of 6 months duration. Neurologic examination and results of routine hematologic and biochemical examination were normal. Cervical spine MRI revealed a low signal bony lesion on T1 and T2 images. Considering the signal characteristics, initial diagnosis of sclerosis was made. Reviewing the cervical X-ray, a round faint lytic lesion was detected. Correlation with cervical computed tomography scan showed the lesion being of air density, compatible with the diagnosis of pneumatocyst. Intraosseous pneumatocyst of cervical spine is a benign finding, which needs no specific treatment; however, it must be included in the differential diagnosis of lucent vertebral lesions seen on conventional radiography and should be differentiated from bony neoplasm and osteomyelitis by its characteristic imaging findings.

A haptic unit designed for magnetic-resonance-guided biopsy.

PubMed

Tse, Z T H; Elhawary, H; Rea, M; Young, I; Davis, B L; Lamperth, M

2009-02-01

The magnetic fields present in the magnetic resonance (MR) environment impose severe constraints on any mechatronic device present in its midst, requiring alternative actuators, sensors, and materials to those conventionally used in traditional system engineering. In addition the spatial constraints of closed-bore scanners require a physical separation between the radiologist and the imaged region of the patient. This configuration produces a loss of the sense of touch from the target anatomy for the clinician, which often provides useful information. To recover the force feedback from the tissue, an MR-compatible haptic unit, designed to be integrated with a five-degrees-of-freedom mechatronic system for MR-guided prostate biopsy, has been developed which incorporates position control and force feedback to the operator. The haptic unit is designed to be located inside the scanner isocentre with the master console in the control room. MR compatibility of the device has been demonstrated, showing a negligible degradation of the signal-to-noise ratio and virtually no geometric distortion. By combining information from the position encoder and force sensor, tissue stiffness measurement along the needle trajectory is demonstrated in a lamb liver to aid diagnosis of suspected cancerous tissue.

Magnetic resonance imaging findings of the pancreas in patients with Shwachman-Diamond syndrome and mutations in the SBDS gene.

PubMed

Toiviainen-Salo, Sanna; Raade, Merja; Durie, Peter R; Ip, Wan; Marttinen, Eino; Savilahti, Erkki; Mäkitie, Outi

2008-03-01

Pancreatic MRI was evaluated in 14 patients with a clinical diagnosis of Shwachman-Diamond syndrome, and the findings were correlated with Shwachman-Bodian-Diamond gene (SBDS) genotype. The findings suggest that patients with mutations in the SBDS gene have a characteristic magnetic resonance imaging pattern of fat-replaced pancreas and that SBDS mutations are unlikely in patients without this pattern.

Resonant magnetic scattering of polarized soft x rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sacchi, M.; Hague, C.F.; Gullikson, E.M.

1997-04-01

Magnetic effects on X-ray scattering (Bragg diffraction, specular reflectivity or diffuse scattering) are a well known phenomenon, and they also represent a powerful tool for investigating magnetic materials since it was shown that they are strongly enhanced when the photon energy is tuned across an absorption edge (resonant process). The resonant enhancement of the magnetic scattering has mainly been investigated at high photon energies, in order to match the Bragg law for the typical lattice spacings of crystals. In the soft X-ray range, even larger effects are expected, working for instance at the 2p edges of transition metals of themore » first row or at the 3d edges of rare earths (300-1500 eV), but the corresponding long wavelengths prevent the use of single crystals. Two approaches have been recently adopted in this energy range: (i) the study of the Bragg diffraction from artificial structures of appropriate 2d spacing; (ii) the analysis of the specular reflectivity, which contains analogous information but has no constraints related to the lattice spacing. Both approaches have their own specific advantages: for instance, working under Bragg conditions provides information about the (magnetic) periodicity in ordered structures, while resonant reflectivity can easily be related to electronic properties and absorption spectra. An important aspect common to all the resonant X-ray scattering techniques is the element selectivity inherent to the fact of working at a specific absorption edge: under these conditions, X-ray scattering becomes in fact a spectroscopy. Results are presented for films of iron and cobalt.« less

Geometric Computation of Human Gyrification Indexes from Magnetic Resonance Images

DTIC Science & Technology

2009-04-01

GEOMETRIC COMPUTATION OF HUMAN GYRIFICATION INDEXES FROM MAGNETIC RESONANCE IMAGES By Shu Su Tonya White Marcus Schmidt Chiu-Yen Kao and Guillermo...00-2009 to 00-00-2009 4. TITLE AND SUBTITLE Geometric Computation of Human Gyrification Indexes from Magnetic Resonance Images 5a. CONTRACT NUMBER... Geometric Computation of Gyrification Indexes Chiu-Yen Kao 1 Geometric Computation of Human Gyrification

Performance of magnetic resonance imaging in the evaluation of first-time and reoperative primary hyperparathyroidism.

PubMed

Kluijfhout, Wouter P; Venkatesh, Shriya; Beninato, Toni; Vriens, Menno R; Duh, Quan-Yang; Wilson, David M; Hope, Thomas A; Suh, Insoo

2016-09-01

Preoperative imaging in patients with primary hyperparathyroidism and a previous parathyroid operation is essential; however, performance of conventional imaging is poor in this subgroup. Magnetic resonance imaging appears to be a good alternative, though overall evidence remains scarce. We retrospectively investigated the performance of magnetic resonance imaging in patients with and without a previous parathyroid operation, with a separate comparison for dynamic gadolinium-enhanced magnetic resonance imaging. All patients undergoing magnetic resonance imaging prior to parathyroidectomy for primary hyperparathyroidism (first time or recurrent) between January 2000 and August 2015 at a high-volume, tertiary care, referral center for endocrine operations were included. We compared the sensitivity and positive predictive value of magnetic resonance imaging with conventional ultrasound and sestamibi on a per-lesion level. A total of 3,450 patients underwent parathyroidectomy, of which 84 patients with recurrent (n = 10) or persistent (n = 74) disease and 41 patients with a primary operation were included. Magnetic resonance imaging had a sensitivity and positive predictive value of 79.9% and 84.7%, respectively, and performance was good in both patients with and without a previous parathyroid operation. Adding magnetic resonance imaging to the combination of ultrasound and sestamibi resulted in a significant increase in sensitivity from 75.2% to 91.5%. Dynamic magnetic resonance imaging produced excellent results in the reoperative group, with sensitivity and a positive predictive value of 90.1%. Technologic advances have enabled faster and more accurate magnetic resonance imaging protocols, making magnetic resonance imaging an excellent alternative modality without associated ionizing radiation. Our study shows that the sensitivity of multimodality imaging for parathyroid adenomas improved significantly with the use of conventional and dynamic magnetic resonance

A technique for magnetic resonance imaging of equine cadaver specimens.

PubMed

Widmer, W R; Buckwalter, K A; Hill, M A; Fessler, J F; Ivancevich, S

1999-01-01

We tested an adaptation of a technique for performing magnetic resonance (MR) imaging of human cadaver limbs in the horse. The forelimbs from a normal horse were collected, frozen, and sealed with a paraffin-polymer combination prior to imaging with either a high- or midfield magnetic resonance scanner. Each forelimb was defrosted, scanned, and refrozen on two separate occasions. A five-point scale was used to evaluate the quality of each set of sagittal and transverse, T1-weighted images of each digit. There was no difference in image quality between first and second scans of either specimen (p > 0.05). We conclude that this technique allows investigators to bank tissue specimens for future magnetic resonance imaging without significant loss of image quality.

Magnetic Resonance Imaging of a Liver Hydatid Cyst Invading the Portal Vein and Causing Portal Cavernomatosis.

PubMed

Herek, Duygu; Sungurtekin, Ugur

2015-01-01

Hepatic hydatid cysts rarely invade portal veins causing portal cavernomatosis as a secondary complication. We report the case of a patient with direct invasion of the right portal vein by hydatid cysts causing portal cavernomatosis diagnosed via magnetic resonance imaging (MRI). The presented case highlights the useful application of MRI with T2-weighted images and gadolinium-enhanced T1-weighted images in the diagnosis of hepatic hydatid lesions presenting with a rare complication of portal cavernomatosis.

In vivo magnetization transfer and diffusion-weighted magnetic resonance imaging detects thrombus composition in a mouse model of deep vein thrombosis.

PubMed

Phinikaridou, Alkystis; Andia, Marcelo E; Saha, Prakash; Modarai, Bijan; Smith, Alberto; Botnar, René M

2013-05-01

Deep vein thrombosis remains a major health problem necessitating accurate diagnosis. Thrombolysis is associated with significant morbidity and is effective only for the treatment of unorganized thrombus. We tested the feasibility of in vivo magnetization transfer (MT) and diffusion-weighted magnetic resonance imaging to detect thrombus organization in a murine model of deep vein thrombosis. Deep vein thrombosis was induced in the inferior vena cava of male BALB/C mice. Magnetic resonance imaging was performed at days 1, 7, 14, 21, and 28 after thrombus induction using MT, diffusion-weighted, inversion-recovery, and T1-mapping protocols. Delayed enhancement and T1 mapping were repeated 2 hours after injection of a fibrin contrast agent. Finally, excised thrombi were used for histology. We found that MT and diffusion-weighted imaging can detect histological changes associated with thrombus aging. MT rate (MTR) maps and percentage of MT rate (%MTR) allowed visualization and quantification of the thrombus protein content, respectively. The %MTR increased with thrombus organization and was significantly higher at days 14, 21, and 28 after thrombus induction (days 1, 7, 14, 21, 28: %MTR=2483±451, 2079±1210, 7029±2490, 10 295±4356, 32 994±25 449; PANOVA<0.05). There was a significant positive correlation between the %MTR and the histological protein content of the thrombus (r=0.70; P<0.05). The apparent diffusion coefficient was lower in erythrocyte-rich and collagen-rich thrombus (0.72±0.10 and 0.69±0.05 [×10(-3) mm(2)/s]). Thrombus at days 7 and 14 had the highest apparent diffusion coefficient values (0.95±0.09 and 1.10±0.18 [×10(-3) mm(2)/s]). MT and diffusion-weighted magnetic resonance imaging sequences are promising for the staging of thrombus composition and could be useful in guiding medical intervention.

Resonant Magnetic Field Sensors Based On MEMS Technology.

PubMed

Herrera-May, Agustín L; Aguilera-Cortés, Luz A; García-Ramírez, Pedro J; Manjarrez, Elías

2009-01-01

Microelectromechanical systems (MEMS) technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI) and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration.

Resonant Magnetic Field Sensors Based On MEMS Technology

PubMed Central

Herrera-May, Agustín L.; Aguilera-Cortés, Luz A.; García-Ramírez, Pedro J.; Manjarrez, Elías

2009-01-01

Microelectromechanical systems (MEMS) technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI) and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration. PMID:22408480

Preliminary evaluation of magnetic resonance fresh blood imaging for diagnosis of Budd-Chiari syndrome.

PubMed

Ren, Ke; Xu, Ke; Sun, Wen-ge; Chen, Yu-shuai; Qi, Xi-xun; Li, Ran-liang; Jin, An-yu

2007-01-20

Budd-Chiari syndrome (BCS) is a rare disease with portal hypertension caused by the blockage of the hepatic vein and/or the inferior vena cava (IVC). Angiography is the "golden standard" for diagnosis, but it is an invasive examination. To assess the diagnostic value of a fresh blood imaging (FBI) relative to BCS, we used a magnetic resonance angiography (MRA) with an FBI sequence for a preoperative evaluation of the BCS patients in this study. Fifty patients who were suspected of having BCS after they had been checked by a B-ultrasound were studied. 2D and 3D FBI were performed on a 1.5T superconductive MR scanner. Original images were rebuilt using a maximal intensity projection (MIP) method on the console. Two doctors reviewed all images before they learned of the angiography results. We then compared the diagnoses obtained from the FBI and angiography results to evaluate the diagnostic value of the FBI. Forty-one patients were diagnosed as BCS and 9 as non-BCS based on an angiography. The FBI correctly diagnosed 38 patients, incorrectly diagnosed 1 patient, and missed diagnosis in 3 patients. Thus, the diagnostic sensitivity of the FBI is 93% (38/41), the specificity is 89% (8/9) and the accuracy is 92% (46/50). The FBI images of the 13 membranous stenoses of the IVC showed a sudden stenosis of the post-liver segment of the IVC. The Images of the 5 patients with a membranous obstruction of the IVC showed IVC thickening and an absence of blood signals in the post-hepatic segment of the IVC. The images of the 4 patients with the segmental thrombosis of the IVC showed abnormal and intermittent signals in the IVC. The images of the 6 patients with a simple hepatic vein obstruction showed obstructive hepatic veins. The images of the 6 patients with the stenosis of both the IVC and the hepatic veins showed the stenosis of the IVC, the thickening of the hepatic veins and the formation of a compensatory circulation within the liver. Lastly, the images of the 7 patients

Optical investigation of domain resonances in magnetic garnet films

NASA Astrophysics Data System (ADS)

Bahlmann, N.; Gerhardt, R.; Dötsch, H.

1996-08-01

Magnetic garnet films of composition (Y,Bi) 3(Fe,Al) 5O 12 are grown by liquid phase epitaxy on [111] oriented substrates of Gd 3Ga 5O 12. Lattices of parallel stripe domains are stabilized by a static induction applied in the film plane. The two branches DR ± of the domain resonance and the domain wall resonance DWR are excited by microwave magnetic fields in the frequency range up to 6 GHz. Light passing the stripe domain lattice parallel to the film normal is modulated at the excitation frequency. A modulation bandwidth of more than 2 GHz is observed. The resonances can be calculated with high accuracy by a hybridization model, if the quality factor Q of the film exceeds 0.5. For Q < 0.5 a simple approximation is used to describe the superposition of the DR + and DR - resonances. The superposition model predicts two stability states of the resonance DR + which are observed experimentally. From the optical measurements precession angles of the resonance DR - of nearly 6° and wall oscillation amplitudes up to 25 nm are derived.

Magnetic resonance imaging and immunohistochemistry of primary vertebral hemangiosarcoma in a dog and implications for diagnosis and therapy.

PubMed

Pérez-Martínez, Claudia; Regueiro-Purriños, Marta; Fernández-Martínez, Beatriz; Altónaga, José R; Gonzalo-Orden, José M; García-Iglesias, María J

2016-12-01

A vertebral mass in a dog with an acute onset paraparesis was identified by magnetic resonance imaging. A poorly differentiated hemangiosarcoma was diagnosed by histopathology and immunohistochemistry. Endothelial nitric oxide synthase could be a new differential marker for poorly differentiated hemangiosarcoma in dogs. Immunohistochemical detection of p53 phosphorylated at Serine 392 , p53, CD117, and CD44 suggest targets for design of therapeutic strategies.

Fluorine-19 magnetic resonance imaging probe for the detection of tau pathology in female rTg4510 mice.

PubMed

Yanagisawa, Daijiro; Ibrahim, Nor Faeizah; Taguchi, Hiroyasu; Morikawa, Shigehiro; Kato, Tomoko; Hirao, Koichi; Shirai, Nobuaki; Sogabe, Takayuki; Tooyama, Ikuo

2018-05-01

Aggregation of tau into neurofibrillary tangles (NFTs) is characteristic of tauopathies, including Alzheimer's disease. Recent advances in tau imaging have attracted much attention because of its potential contributions to early diagnosis and monitoring of disease progress. Fluorine-19 magnetic resonance imaging ( 19 F-MRI) may be extremely useful for tau imaging once a high-quality probe has been formulated. In this investigation, a novel fluorine-19-labeling compound has been developed as a probe for tau imaging using 19 F-MRI. This compound is a buta-1,3-diene derivative with a polyethylene glycol side chain bearing a CF 3 group and is known as Shiga-X35. Female rTg4510 mice (a mouse model of tauopathy) and wild-type mice were intravenously injected with Shiga-X35, and magnetic resonance imaging of each mouse's head was conducted in a 7.0-T horizontal-bore magnetic resonance scanner. The 19 F-MRI in rTg4510 mice showed an intense signal in the forebrain region. Analysis of the signal intensity in the forebrain region revealed a significant accumulation of fluorine-19 magnetic resonance signal in the rTg4510 mice compared with the wild-type mice. Histological analysis showed fluorescent signals of Shiga-X35 binding to the NFTs in the brain sections of rTg4510 mice. Data collected as part of this investigation indicate that 19 F-MRI using Shiga-X35 could be a promising tool to evaluate tau pathology in the brain. © 2017 Wiley Periodicals, Inc.

Algorithmic cooling in liquid-state nuclear magnetic resonance

NASA Astrophysics Data System (ADS)

Atia, Yosi; Elias, Yuval; Mor, Tal; Weinstein, Yossi

2016-01-01

Algorithmic cooling is a method that employs thermalization to increase qubit purification level; namely, it reduces the qubit system's entropy. We utilized gradient ascent pulse engineering, an optimal control algorithm, to implement algorithmic cooling in liquid-state nuclear magnetic resonance. Various cooling algorithms were applied onto the three qubits of C132-trichloroethylene, cooling the system beyond Shannon's entropy bound in several different ways. In particular, in one experiment a carbon qubit was cooled by a factor of 4.61. This work is a step towards potentially integrating tools of NMR quantum computing into in vivo magnetic-resonance spectroscopy.

Methotrexate-conjugated magnetic nanoparticles for thermochemotherapy and magnetic resonance imaging of tumor

NASA Astrophysics Data System (ADS)

Gao, Fuping; Yan, Zixing; Zhou, Jing; Cai, Yuanyuan; Tang, Jintian

2012-10-01

There is significant interest in recent years in developing magnetic nanoparticles (MNPs) having multifunctional characteristics with complimentary roles. In this study, methotrexate (MTX) was conjugated on the iron oxide magnetic nanoparticles surface via a poly(ethyleneimine) self-assembled monolayer (MTX-MNPs). The novel platform combined cancer chemotherapy, hyperthermia and potential monitoring of the progression of disease through magnetic resonance imaging (MRI). The conjugation of MTX on the magnetite surface was confirmed by Fourier transform infrared spectroscopy and change of zeta potential. Transmission electron microscope (TEM) showed that MTX-MNPs were morphologically spherical. The average diameter of MTX-MNPs was 30.1 ± 5.2 nm determined by dynamic light scattering. Magnetic measurements revealed that the saturation magnetization of MTX-MNPs reached 68.8 emu/g and the nanoparticles were superparamagnetic. The MTX-MNPs had good heating properties in an alternating magnetic field. TEM results showed that a larger number of MTX-MNPs were internalized into the MCF-7 cellular cytoplasm compared with the MNPs. The MTX-MNPs demonstrated highly synergistic antiproliferative effects of simultaneous chemotherapy and hyperthermia in MCF-7 breast cancer cells. A significant negative contrast enhancement was observed with magnetic resonance phantom imaging for MCF-7 cells over L929cells, when both were cultured with the nanoconjugate. The MTX-MNPs with combined characteristics of thermochemotherapy and MRI could be of high clinical significance in the treatment of tumor.

Exploring on the Sensitivity Changes of the LC Resonance Magnetic Sensors Affected by Superposed Ringing Signals.

PubMed

Lin, Tingting; Zhou, Kun; Yu, Sijia; Wang, Pengfei; Wan, Ling; Zhao, Jing

2018-04-25

LC resonance magnetic sensors are widely used in low-field nuclear magnetic resonance (LF-NMR) and surface nuclear magnetic resonance (SNMR) due to their high sensitivity, low cost and simple design. In magnetically shielded rooms, LC resonance magnetic sensors can exhibit sensitivities at the fT/√Hz level in the kHz range. However, since the equivalent magnetic field noise of this type of sensor is greatly affected by the environment, weak signals are often submerged in practical applications, resulting in relatively low signal-to-noise ratios (SNRs). To determine why noise increases in unshielded environments, we analysed the noise levels of an LC resonance magnetic sensor ( L ≠ 0) and a Hall sensor ( L ≈ 0) in different environments. The experiments and simulations indicated that the superposed ringing of the LC resonance magnetic sensors led to the observed increase in white noise level caused by environmental interference. Nevertheless, ringing is an inherent characteristic of LC resonance magnetic sensors. It cannot be eliminated when environmental interference exists. In response to this problem, we proposed a method that uses matching resistors with various values to adjust the quality factor Q of the LC resonance magnetic sensor in different measurement environments to obtain the best sensitivity. The LF-NMR experiment in the laboratory showed that the SNR is improved significantly when the LC resonance magnetic sensor with the best sensitivity is selected for signal acquisition in the light of the test environment. (When the matching resistance is 10 kΩ, the SNR is 3.46 times that of 510 Ω). This study improves LC resonance magnetic sensors for nuclear magnetic resonance (NMR) detection in a variety of environments.

Black-blood thrombus imaging (BTI): a contrast-free cardiovascular magnetic resonance approach for the diagnosis of non-acute deep vein thrombosis.

PubMed

Xie, Guoxi; Chen, Hanwei; He, Xueping; Liang, Jianke; Deng, Wei; He, Zhuonan; Ye, Yufeng; Yang, Qi; Bi, Xiaoming; Liu, Xin; Li, Debiao; Fan, Zhaoyang

2017-01-18

Deep vein thrombosis (DVT) is a common but elusive illness that can result in long-term disability or death. Accurate detection of thrombosis and assessment of its size and distribution are critical for treatment decision-making. In the present study, we sought to develop and evaluate a cardiovascular magnetic resonance (CMR) black-blood thrombus imaging (BTI) technique, based on delay alternating with nutation for tailored excitation black-blood preparation and variable flip angle turbo-spin-echo readout, for the diagnosis of non-acute DVT. METHODS: This prospective study was approved by institutional review board and informed consent obtained from all subjects. BTI was first conducted in 11 healthy subjects for parameter optimization and then conducted in 18 non-acute DVT patients to evaluate its diagnostic performance. Two clinically used CMR techniques, contrast-enhanced CMR venography (CE-MRV) and three dimensional magnetization prepared rapid acquisition gradient echo (MPRAGE), were also conducted in all patients for comparison. All images obtained from patients were analyzed on a per-segment basis. Using the consensus diagnosis of CE-MRV as the reference, the sensitivity (SE), specificity (SP), positive and negative predictive values (PPV and NPV), and accuracy (ACC) of BTI and MPRAGE as well as their diagnostic agreement with CE-MRV were calculated. Besides, diagnostic confidence and interreader diagnostic agreement were evaluated for all three techniques. BTI with optimized parameters effectively nulled the venous blood flow signal and allowed directly visualizing the thrombus within the black-blood lumen. Higher SE (90.4% vs 67.6%), SP (99.0% vs. 97.4%), PPV (95.4% vs. 85.6%), NPV (97.8% vs 92.9%) and ACC (97.4% vs. 91.8%) were obtained by BTI in comparison with MPRAGE. Good diagnostic confidence and excellent diagnostic and interreader agreements were achieved by BTI, which were superior to MPRAGE on detecting the chronic thrombus. BTI allows

Primary Angiitis of the Central Nervous System: Magnetic Resonance Imaging Spectrum of Parenchymal, Meningeal, and Vascular Lesions at Baseline.

PubMed

Boulouis, Grégoire; de Boysson, Hubert; Zuber, Mathieu; Guillevin, Loïc; Meary, Eric; Costalat, Vincent; Pagnoux, Christian; Naggara, Olivier

2017-05-01

Primary angiitis of the central nervous system remains challenging. To report an overview and pictorial review of brain magnetic resonance imaging findings in adult primary angiitis of the central nervous system and to determine the distribution of parenchymal, meningeal, and vascular lesions in a large multicentric cohort. Adult patients from the French COVAC cohort (Cohort of Patients With Primary Vasculitis of the Central Nervous System), with biopsy or angiographically proven primary angiitis of the central nervous system and brain magnetic resonance imaging available at the time of diagnosis were included. A systematic imaging review was performed blinded to clinical data. Sixty patients met inclusion criteria. Mean age was 45 years (±12.9). Patients initially presented focal deficit(s) (83%), headaches (53%), cognitive disorder (40%), and seizures (38.3%). The most common magnetic resonance imaging finding observed in 42% of patients was multiterritorial, bilateral, distal acute stroke lesions after small to medium artery distribution, with a predominant carotid circulation distribution. Hemorrhagic infarctions and parenchymal hemorrhages were also frequently found in the cohort (55%). Acute convexity subarachnoid hemorrhage was found in 26% of patients and 42% demonstrated pre-eminent leptomeningeal enhancement, which is found to be significantly more prevalent in biopsy-proven patients (60% versus 28%; P =0.04). Seven patients had tumor-like presentations. Seventy-seven percent of magnetic resonance angiographic studies were abnormal, revealing proximal/distal stenoses in 57% and 61% of patients, respectively. Adult primary angiitis of the central nervous system is a heterogenous disease, with multiterritorial, distal, and bilateral acute stroke being the most common pattern of parenchymal lesions found on magnetic resonance imaging. Our findings suggest a higher than previously thought prevalence of hemorrhagic transformation and other hemorrhagic

Magnetic resonance imaging of the preterm infant brain.

PubMed

Doria, Valentina; Arichi, Tomoki; Edwards, David A

2014-01-01

Despite improvements in neonatal care, survivors of preterm birth are still at a significantly increased risk of developing life-long neurological difficulties including cerebral palsy and cognitive difficulties. Cranial ultrasound is routinely used in neonatal practice, but has a low sensitivity for identifying later neurodevelopmental difficulties. Magnetic Resonance Imaging (MRI) can be used to identify intracranial abnormalities with greater diagnostic accuracy in preterm infants, and theoretically might improve the planning and targeting of long-term neurodevelopmental care; reducing parental stress and unplanned healthcare utilisation; and ultimately may improve healthcare cost effectiveness. Furthermore, MR imaging offers the advantage of allowing the quantitative assessment of the integrity, growth and function of intracranial structures, thereby providing the means to develop sensitive biomarkers which may be predictive of later neurological impairment. However further work is needed to define the accuracy and value of diagnosis by MR and the techniques's precise role in care pathways for preterm infants.

Magnetic resonance imaging of the central nervous system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1988-02-26

This report reviews the current applications of magnetic resonance imaging of the central nervous system. Since its introduction into the clinical environment in the early 1980's, this technology has had a major impact on the practice of neurology. It has proved to be superior to computed tomography for imaging many diseases of the brain and spine. In some instances it has clearly replaced computed tomography. It is likely that it will replace myelography for the assessment of cervicomedullary junction and spinal regions. The magnetic field strengths currently used appear to be entirely safe for clinical application in neurology except inmore » patients with cardiac pacemakers or vascular metallic clips. Some shortcomings of magnetic resonance imaging include its expense, the time required for scanning, and poor visualization of cortical bone.« less

Effect of resonant magnetic perturbations on three dimensional equilibria in the Madison Symmetric Torus reversed-field pinch

NASA Astrophysics Data System (ADS)

Munaretto, S.; Chapman, B. E.; Nornberg, M. D.; Boguski, J.; DuBois, A. M.; Almagri, A. F.; Sarff, J. S.

2016-05-01

The orientation of 3D equilibria in the Madison Symmetric Torus (MST) [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)] reversed-field pinch can now be controlled with a resonant magnetic perturbation (RMP). Absent the RMP, the orientation of the stationary 3D equilibrium varies from shot to shot in a semi-random manner, making its diagnosis difficult. Produced with a poloidal array of saddle coils at the vertical insulated cut in MST's thick conducting shell, an m = 1 RMP with an amplitude br/B ˜ 10% forces the 3D structure into any desired orientation relative to MST's diagnostics. This control has led to improved diagnosis, revealing enhancements in both the central electron temperature and density. With sufficient amplitude, the RMP also inhibits the generation of high-energy (>20 keV) electrons, which otherwise emerge due to a reduction in magnetic stochasticity in the core. Field line tracing reveals that the RMP reintroduces stochasticity to the core. A m = 3 RMP of similar amplitude has little effect on the magnetic topology or the high-energy electrons.

The resonant radio-frequency magnetic probe tuned by coaxial cable.

PubMed

Sun, B; Huo, W G; Ding, Z F

2012-08-01

In this paper, the resonant rf magnetic probe is upgraded by replacing the rotary capacitor in the old version with the series-connected coaxial cable. The numerical calculation and the measurement with the prototype probe show that the rf magnetic probe can achieve resonance at a middle length of the series-connected coaxial cable. The good electrical symmetry of the new rf magnetic probe is ensured by both the identity of series-connected coaxial cables and the new structure of the primary winding. Practical measurements conduced on an rf inductively coupled plasma source demonstrate that performances of the new rf magnetic probe are good.

The use of high resolution magnetic resonance on 3.0-T system in the diagnosis and surgical planning of intraosseous lesions of the jaws: preliminary results of a retrospective study.

PubMed

Cassetta, M; Di Carlo, S; Pranno, N; Stagnitti, A; Pompa, V; Pompa, G

2012-12-01

The pre-operative evaluation in oral and maxillofacial surgery is currently performed by computerized tomography (CT). However in some case the information of the traditional imaging methods are not enough in the diagnosis and surgical planning. The efficacy of these imaging methods in the evaluation of soft tissues is lower than magnetic resonance imaging (MRI). The aim of the study was to show the use of MRI in the evaluation of relation between intraosseous lesions of the jaws and anatomical structures, when it was difficult using the traditional radiographic methods, and to evaluate the usefulness of MRI to depict the morphostructural characterization of the lesions and infiltration of the soft tissues. 10 patients with a lesion of jaw were selected. All the patients underwent panoramic radiography (OPT), CT and MRI. The images were examined by dental and maxillofacial radiology who compared the different imaging methods to analyze the morphological and structural characteristics of the lesion and assessed the relationship between the lesion and the anatomical structures. Magnetic resonance imaging provided more detailed spatial and structural information than other imaging methods. MRI allowed us to characterize the intraosseous lesions of the jaws and to plan the surgery, resulting in a lower risk of anatomic structures surgical injury.

Miniature Magnet for Electron Spin Resonance Experiments

ERIC Educational Resources Information Center

Rupp, L. W.; And Others

1976-01-01

Describes commercially available permanent magnets that have been incorporated in a compact and inexpensive structure providing both field sweep and modulation suitable for electron spin resonance at microwave frequencies. (MLH)

Detecting prostate cancer and prostatic calcifications using advanced magnetic resonance imaging

PubMed Central

Dou, Shewei; Bai, Yan; Shandil, Ankit; Ding, Degang; Shi, Dapeng; Haacke, E Mark; Wang, Meiyun

2017-01-01

Prostate cancer and prostatic calcifications have a high incidence in elderly men. We aimed to investigate the diagnostic capabilities of susceptibility-weighted imaging in detecting prostate cancer and prostatic calcifications. A total number of 156 men, including 34 with prostate cancer and 122 with benign prostate were enrolled in this study. Computed tomography, conventional magnetic resonance imaging, diffusion-weighted imaging, and susceptibility-weighted imaging were performed on all the patients. One hundred and twelve prostatic calcifications were detected in 87 patients. The sensitivities and specificities of the conventional magnetic resonance imaging, apparent diffusion coefficient, and susceptibility-filtered phase images in detecting prostate cancer and prostatic calcifications were calculated. McNemar's Chi-square test was used to compare the differences in sensitivities and specificities between the techniques. The results showed that the sensitivity and specificity of susceptibility-filtered phase images in detecting prostatic cancer were greater than that of conventional magnetic resonance imaging and apparent diffusion coefficient (P < 0.05). In addition, the sensitivity and specificity of susceptibility-filtered phase images in detecting prostatic calcifications were comparable to that of computed tomography and greater than that of conventional magnetic resonance imaging and apparent diffusion coefficient (P < 0.05). Given the high incidence of susceptibility-weighted imaging (SWI) abnormality in prostate cancer, we conclude that susceptibility-weighted imaging is more sensitive and specific than conventional magnetic resonance imaging, diffusion-weighted imaging, and computed tomography in detecting prostate cancer. Furthermore, susceptibility-weighted imaging can identify prostatic calcifications similar to computed tomography, and it is much better than conventional magnetic resonance imaging and diffusion-weighted imaging. PMID:27004542

Applicability of McDonald 2010 and Magnetic Resonance Imaging in Multiple Sclerosis (MAGNIMS) 2016 Magnetic Resonance Imaging Criteria for the Diagnosis of Multiple Sclerosis in Sri Lanka.

PubMed

Gamage, Sujani Madhurika Kodagoda; Wijeweera, Indunil; Wijesinghe, Priyangi; Adikari, Sanjaya Bandara; Fink, Katharina; Sominanda, Herath Mudiyanselage Ajith

2018-05-31

The magnetic resonance imaging in multiple sclerosis (MAGNIMS) group recently proposed guidelines to replace the existing dissemination-in-space criteria in McDonald 2010 magnetic resonance imaging (MRI) criteria for diagnosing multiple sclerosis. There has been insufficient research regarding their applicability in Asians. Objective of this study was to determine the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of McDonald 2010 and MAGNIMS 2016 MRI criteria with the aim of verifying their applicability in Sri Lankan patients. Patients with clinically isolated syndrome diagnosed by consultant neurologists were recruited from five major neurology centers. Baseline and follow-up MRI scans were performed within 3 months from the initial presentation and at one year after baseline MRI, respectively. McDonald 2010 and MAGNIMS 2016 MRI criteria were applied to all MRI scans. Patients were followed-up for 2 years to assess the conversion to clinically definite multiple sclerosis (CDMS). The sensitivity, specificity, accuracy, PPV, and NPV for predicting the conversion to CDMS were calculated. Forty-two of 66 patients converted to CDMS. Thirty-seven fulfilled the McDonald 2010 MRI criteria, and 33 converted to CDMS. MAGNIMS 2016 MRI criteria were fulfilled by 29, with 28 converting to CDMS. The sensitivity, specificity, accuracy, PPV, and NPV were 78%, 83%, 64%, 89%, and 69%, respectively, for the McDonald 2010 criteria, and 67%, 96%, 77%, 96%, and 62% for the MAGNIMS 2016 MRI criteria. MAGNIMS 2016 MRI criteria were superior to McDonald 2010 MRI criteria in specificity, accuracy, and PPV, but inferior in sensitivity and NPV. Copyright © 2018 Korean Neurological Association.

Magnetic x-ray linear dichroism in resonant and non-resonant Gd 4f photoemission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishra, S.; Gammon, W.J.; Pappas, D.P.

1997-04-01

The enhancement of the magnetic linear dichroism in resonant 4f photoemission (MLDRPE) is studied from a 50 monolayer film of Gd/Y(0001). The ALS at beamline 7.0.1 provided the source of linearly polarized x-rays used in this study. The polarized light was incident at an angle of 30 degrees relative to the film plane, and the sample magnetization was perpendicular to the photon polarization. The linear dichroism of the 4f core levels is measured as the photon energy is tuned through the 4d-4f resonance. The authors find that the MLDRPE asymmetry is strongest at the resonance. Near the threshold the asymmetrymore » has several features which are out of phase with the fine structure of the total yield.« less

Differential diagnosis of benign and malignant breast masses using diffusion-weighted magnetic resonance imaging.

PubMed

Min, Qinghua; Shao, Kangwei; Zhai, Lulan; Liu, Wei; Zhu, Caisong; Yuan, Lixin; Yang, Jun

2015-02-07

Diffusion-weighted magnetic resonance imaging (DW-MRI) is different from conventional diagnostic methods and has the potential to delineate the microscopic anatomy of a target tissue or organ. The purpose of our study was to evaluate the value of DW-MRI in the diagnosis of benign and malignant breast masses, which would help the clinical surgeon to decide the scope and pattern of operation. A total of 52 female patients with palpable solid breast masses received breast MRI scans using routine sequences, dynamic contrast-enhanced imaging, and diffusion-weighted echo-planar imaging at b values of 400, 600, and 800 s/mm(2), respectively. Two regions of interest (ROIs) were plotted, with a smaller ROI for the highest signal and a larger ROI for the overall lesion. Apparent diffusion coefficient (ADC) values were calculated at three different b values for all detectable lesions and from two different ROIs. The sensitivity, specificity, positive predictive value, and positive likelihood ratio of DW-MRI were determined for comparison with histological results. A total of 49 (49/52, 94.2%) lesions were detected using DW-MRI, including 20 benign lesions (two lesions detected in the same patient) and 29 malignant lesions. Benign lesion had a higher mean ADC value than their malignant counterparts, regardless of b value. According to the receiver operating characteristic (ROC) curve, the smaller-range ROI was more effective in differentiation between benign and malignant lesions. The area under the ROC curve was the largest at a b value of 800 s/mm(2). With a threshold ADC value at 1.23 × 10(-3) mm(2)/s, DW-MRI achieved a sensitivity of 82.8%, specificity of 90.0%, positive predictive value of 92.3%, and positive likelihood ratio of 8.3 for differentiating benign and malignant lesions. DW-MRI is an accurate diagnostic tool for differentiation between benign and malignant breast lesions, with an optimal b value of 800 s/mm(2). A smaller-range ROI focusing on the

Biomedical Investigations with Laser-Polarized Noble Gas Magnetic Resonance

NASA Technical Reports Server (NTRS)

Walsworth, Ronald L.

2003-01-01

We pursued advanced technology development of laser-polarized noble gas nuclear magnetic resonance (NMR) as a novel biomedical imaging tool for ground-based and eventually space-based application. This new multidisciplinary technology enables high-resolution gas-space magnetic resonance imaging (MRI)-e.g., of lung ventilation-as well as studies of tissue perfusion. In addition, laser-polarized noble gases (3He and 129Xe) do not require a large magnetic field for sensitive detection, opening the door to practical MRI at very low magnetic fields with an open, lightweight, and low-power device. We pursued two technology development specific aims: (1) development of low-field (less than 0.01 T) noble gas MRI of humans; and (2) development of functional MRI of the lung using laser-polarized noble gas and related techniques.

Using 3 Tesla magnetic resonance imaging in the pre-operative evaluation of tongue carcinoma.

PubMed

Moreno, K F; Cornelius, R S; Lucas, F V; Meinzen-Derr, J; Patil, Y J

2017-09-01

This study aimed to evaluate the role of 3 Tesla magnetic resonance imaging in predicting tongue tumour thickness via direct and reconstructed measures, and their correlations with corresponding histological measures, nodal metastasis and extracapsular spread. A prospective study was conducted of 25 patients with histologically proven squamous cell carcinoma of the tongue and pre-operative 3 Tesla magnetic resonance imaging from 2009 to 2012. Correlations between 3 Tesla magnetic resonance imaging and histological measures of tongue tumour thickness were assessed using the Pearson correlation coefficient: r values were 0.84 (p < 0.0001) and 0.81 (p < 0.0001) for direct and reconstructed measurements, respectively. For magnetic resonance imaging, direct measures of tumour thickness (mean ± standard deviation, 18.2 ± 7.3 mm) did not significantly differ from the reconstructed measures (mean ± standard deviation, 17.9 ± 7.2 mm; r = 0.879). Moreover, 3 Tesla magnetic resonance imaging had 83 per cent sensitivity, 82 per cent specificity, 82 per cent accuracy and a 90 per cent negative predictive value for detecting cervical lymph node metastasis. In this cohort, 3 Tesla magnetic resonance imaging measures of tumour thickness correlated highly with the corresponding histological measures. Further, 3 Tesla magnetic resonance imaging was an effective method of detecting malignant adenopathy with extracapsular spread.