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Sample records for 3-tesla magnetic resonance

  1. Prevalence of Incidental Pancreatic Cysts on 3 Tesla Magnetic Resonance

    de Oliveira, Patricia Bedesco; Puchnick, Andrea; Szejnfeld, Jacob; Goldman, Suzan Menasce

    2015-01-01

    Objectives To ascertain the prevalence of pancreatic cysts detected incidentally on 3-Tesla magnetic resonance imaging (MRI) of the abdomen and correlate this prevalence with patient age and gender; assess the number, location, and size of these lesions, as well as features suspicious for malignancy; and determine the prevalence of incidentally detected dilatation of the main pancreatic duct (MPD). Methods Retrospective analysis of 2,678 reports of patients who underwent abdominal MRI between...

  2. Magnetic resonance imaging of articular cartilage at 3 tesla

    Smooth motor function can be maintained by articular cartilage. When the cartilage is injured, edema occurs, and as degeneration progresses, the cartilage thins and the cartilage matrix decreases. Magnetic resonance (MR) imaging allows noninvasive evaluation of these changes. Fat suppression proton density- and T2-weighted imaging are useful in the morphologic evaluation of articular cartilage. High resolution, 3-tesla MR imaging provides more detailed evaluation. Biochemical information from T2 mapping, T1ρ mapping, and delayed gadolinium-enhanced MR imaging of cartilage (dGEMRIC) is useful for early diagnosis of cartilage injury and evaluation of cartilage repair. The role of MR imaging in evaluating articular cartilage will increase in the future aging society. (author)

  3. 3-Tesla functional magnetic resonance imaging-guided tumor resection

    Objective: We sought to determine the safety and efficacy of using 3-tesla (T) functional magnetic resonance imaging (fMRI) to guide brain tumor resection. Material and methods: From February 2004 to March 2006, fMRI was performed on 13 patients before surgical resection. Functional imaging was used to identify eloquent cortices for motor (8), speech (3), and motor and speech (2) activation using two different 3-T magnetic resonance (MR) scanners. Surgical resection was accomplished using a 1.5-T intraoperative MR system. Appropriate MR scan sequences were performed intraoperatively to determine and maximize the extent of the surgical resection. Results: Tumors included six oligodendrogliomas, three meningiomas, two astrocytomas and two glioblastomas multiforme. The fMRI data was accurate in all cases. After surgery, two patients had hemiparesis, two had worsening of their speech, and one had worsening of speech and motor function. Neurological function returned to normal in all patients within 1 month. Complete resections were possible in 10 patients (77%). Two patients had incomplete resections because of the proximity of their tumors to functional areas. Biopsy was performed in another patient with an astrocytoma in the motor strip. Conclusion: 3-T fMRI was accurate for locating neurologic function before tumor resection near eloquent cortex. (orig.)

  4. 3-Tesla functional magnetic resonance imaging-guided tumor resection

    Hall, W.A. [Univ. of Minnesota Medical School, Minneapolis, MN (United States). Depts. of Neurosurgery; Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Radiation Oncology; Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Radiology; University of Minnesota Medical Center (MMC), Minneapolis, MN (United States); Truwit, C.L. [Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Radiology; Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Pediatrics; Univ. of Minnesota Medical School, Minneapolis, MN (United States). Dept. of Neurology; Hennepin Country Medical Center, Minneapolis, MN (United States). Dept. of Radiology

    2006-12-15

    Objective: We sought to determine the safety and efficacy of using 3-tesla (T) functional magnetic resonance imaging (fMRI) to guide brain tumor resection. Material and methods: From February 2004 to March 2006, fMRI was performed on 13 patients before surgical resection. Functional imaging was used to identify eloquent cortices for motor (8), speech (3), and motor and speech (2) activation using two different 3-T magnetic resonance (MR) scanners. Surgical resection was accomplished using a 1.5-T intraoperative MR system. Appropriate MR scan sequences were performed intraoperatively to determine and maximize the extent of the surgical resection. Results: Tumors included six oligodendrogliomas, three meningiomas, two astrocytomas and two glioblastomas multiforme. The fMRI data was accurate in all cases. After surgery, two patients had hemiparesis, two had worsening of their speech, and one had worsening of speech and motor function. Neurological function returned to normal in all patients within 1 month. Complete resections were possible in 10 patients (77%). Two patients had incomplete resections because of the proximity of their tumors to functional areas. Biopsy was performed in another patient with an astrocytoma in the motor strip. Conclusion: 3-T fMRI was accurate for locating neurologic function before tumor resection near eloquent cortex. (orig.)

  5. Functional and perfusion magnetic resonance imaging at 3 tesla

    Klarhoefer, M

    2001-01-01

    This thesis deals with the development and optimization of fast magnetic resonance imaging (MRI) methods for non-invasive functional studies of the human brain and perfusion imaging on a 3 Tesla (T) whole body NMR system. The functional MRI (fMRI) experiments performed showed that single-shot multi-echo EPI and spiral imaging techniques provide fast tools to obtain information about T2* distributions during functional activation in the human brain. Both sequences were found to be useful in the separation of different sources contributing to the functional MR signal like inflow or susceptibility effects in the various vascular environments. An fMRI study dealing with the involvement of prefrontal brain regions in movement preparation lead to inconsistent results. It could not be clarified if these were caused by problems during a spatial normalization process of the individual brains or if the functional paradigm, using very short inter-stimulus intervals, was not suited for the problem investigated. Blood flo...

  6. Prevalence of Incidental Pancreatic Cysts on 3 Tesla Magnetic Resonance

    de Oliveira, Patricia Bedesco; Puchnick, Andrea; Szejnfeld, Jacob; Goldman, Suzan Menasce

    2015-01-01

    Objectives To ascertain the prevalence of pancreatic cysts detected incidentally on 3-Tesla magnetic resonance imaging (MRI) of the abdomen and correlate this prevalence with patient age and gender; assess the number, location, and size of these lesions, as well as features suspicious for malignancy; and determine the prevalence of incidentally detected dilatation of the main pancreatic duct (MPD). Methods Retrospective analysis of 2,678 reports of patients who underwent abdominal MRI between January 2012 and June 2013. Patients with a known history of pancreatic conditions or surgery were excluded, and the remaining 2,583 reports were examined for the presence of pancreatic cysts, which was then correlated with patient age and gender. We also assessed whether cysts were solitary or multiple, as well as their location within the pancreatic parenchyma, size, and features suspicious for malignancy. Finally, we calculated the prevalence of incidental MPD dilatation, defined as MPD diameter ≥ 2.5 mm. Results Pancreatic cysts were detected incidentally in 9.3% of patients (239/2,583). The prevalence of pancreatic cysts increased significantly with age (p<0.0001). There were no significant differences in prevalence between men and women (p=0.588). Most cysts were multiple (57.3%), distributed diffusely throughout the pancreas (41.8%), and 5 mm or larger (81.6%). In 12.1% of cases, cysts exhibited features suspicious for malignancy. Overall, 2.7% of subjects exhibited incidental MPD dilatation. Conclusions In this sample, the prevalence of pancreatic cysts detected incidentally on 3T MRI of the abdomen was 9.3%. Prevalence increased with age and was not associated with gender. The majority of cysts were multiple, diffusely distributed through the pancreatic parenchyma, and ≥ 5 mm in size; 12.1% were suspicious for malignancy. An estimated 2.7% of subjects had a dilated MPD. PMID:25798910

  7. Functional and perfusion magnetic resonance imaging at 3 tesla

    This thesis deals with the development and optimization of fast magnetic resonance imaging (MRI) methods for non-invasive functional studies of the human brain and perfusion imaging on a 3 Tesla (T) whole body NMR system. The functional MRI (fMRI) experiments performed showed that single-shot multi-echo EPI and spiral imaging techniques provide fast tools to obtain information about T2* distributions during functional activation in the human brain. Both sequences were found to be useful in the separation of different sources contributing to the functional MR signal like inflow or susceptibility effects in the various vascular environments. An fMRI study dealing with the involvement of prefrontal brain regions in movement preparation lead to inconsistent results. It could not be clarified if these were caused by problems during a spatial normalization process of the individual brains or if the functional paradigm, using very short inter-stimulus intervals, was not suited for the problem investigated. Blood flow velocity measurements in the human finger showed that the use of a strong, small-bore gradient system permits short echo times that reduce flow artefacts and allows high spatial resolution in order to keep systematic errors due to partial volume effects small. With regard to the perfusion investigations an inversion recovery snapshot-FLASH sequence was implemented, which allowed the acquisition of T1 parameter maps of the human brain within a few seconds. The accuracy of this method was demonstrated in test objects. The perfusion investigations with FAIR showed good qualitative results, whereas the quantitative analysis did not yield reproducible findings. A reason for the poor results could be the low signal-to-noise ratio (SNR) of the FAIR images or an incomplete global inversion of the magnetization due to the transmission characteristics of the radio-frequency coil. The BASE sequence that did not require a global inversion yielded quantitative perfusion

  8. Dobutamine stress cardiovascular magnetic resonance at 3 Tesla

    Klein C

    2008-10-01

    Full Text Available Abstract Purpose The assessment of inducible wall motion abnormalities during high-dose dobutamine-stress cardiovascular magnetic resonance (DCMR is well established for the identification of myocardial ischemia at 1.5 Tesla. Its feasibility at higher field strengths has not been reported. The present study was performed to prospectively determine the feasibility and diagnostic accuracy of DCMR at 3 Tesla for depicting hemodynamically significant coronary artery stenosis (≥ 50% diameter stenosis in patients with suspected or known coronary artery disease (CAD. Materials and methods Thirty consecutive patients (6 women (66 ± 9.3 years were scheduled for DCMR between January and May 2007 for detection of coronary artery disease. Patients were examined with a Philips Achieva 3 Tesla system (Philips Healthcare, Best, The Netherlands, using a spoiled gradient echo cine sequence. Technical parameters were: spatial resolution 2 × 2 × 8 mm3, 30 heart phases, spoiled gradient echo TR/TE: 4.5/2.6 msec, flip angle 15°. Images were acquired at rest and stress in accordance with a standardized high-dose dobutamine-atropine protocol during short breath-holds in three short and three long-axis views. Dobutamine was administered using a standard protocol (10 μg increments every 3 minutes up to 40 μg dobutamine/kg body weight/minute plus atropine if required to reach target heart rate. The study protocol included administration of 0.1 mmol/kg/body weight Gd-DTPA before the cine images at rest were acquired to improve the image quality. The examination was terminated if new or worsening wall-motion abnormalities or chest pain occurred or when > 85% of age-predicted maximum heart rate was reached. Myocardial ischemia was defined as new onset of wall-motion abnormality in at least one segment. In addition, late gadolinium enhancement (LGE was performed. Images were evaluated by two blinded readers. Diagnostic accuracy was determined with coronary

  9. Travelling Wave Magnetic Resonance Imaging at 3 Tesla

    Vazquez, F; Martin, R.; Marrufo, O.; Rodriguez, A. O.

    2013-01-01

    Waveguides have been successfully used to generate magnetic resonance images at 7 T with whole-body systems. The bore limits the magnetic resonance signal transmitted because its specific cut-off frequency is greater than the majority of resonant frequencies. This restriction can be overcome by using a parallel-plate waveguide whose cut-off frequency is zero for the transversal electric modes and it can propagate any frequency. To investigate the potential benefits for whole-body imaging at 3...

  10. Travelling Wave Magnetic Resonance Imaging at 3 Tesla

    Vazquez, F; Marrufo, O; Rodriguez, A O

    2013-01-01

    Waveguides have been successfully used to generate magnetic resonance images at 7 T with whole-body systems. The bore limits the magnetic resonance signal transmitted because its specific cut-off frequency is greater than the majority of resonant frequencies. This restriction can be overcome by using a parallel-plate waveguide whose cut-off frequency is zero for the transversal electric modes and it can propagate any frequency. To investigate the potential benefits for whole-body imaging at 3 T, we compare numerical simulations at 1.5 T, 3 T, 7 T, and 9 T via the propagation of the parallel-plate waveguide principal mode filled with a cylindrical phantom and two surface coils. B1 mapping was computed to investigate the feasibility of this approach at 3T. The point spread function method was used to measure the imager performance for the traveling-wave magnetic resonance imaging experiment. Human leg images were acquired to experimentally validate this approach. The principal mode shows very little field magni...

  11. Magnetic resonance imaging of epilepsy at 3 Tesla

    Craven, I., E-mail: ian.craven@sth.nhs.u [Department of Radiology, Royal Hallamshire Hospital, Sheffield (United Kingdom); Griffiths, P.D.; Hoggard, N. [Academic Unit of Radiology, Royal Hallamshire Hospital, Sheffield (United Kingdom)

    2011-03-15

    Patients with epilepsy often have a structural cause for their seizures and may benefit from surgical resection. As recommended in the National Institute of Health and Clinical Excellence (NICE) guidelines, magnetic resonance imaging (MRI) is used to screen for structural abnormalities in these patients and there is increasing evidence that 3T MRI has better sensitivity and specificity than 1.5T. This article reviews the imaging findings of many of the common diseases that can cause epilepsy.

  12. Magnetic resonance imaging of epilepsy at 3 Tesla

    Patients with epilepsy often have a structural cause for their seizures and may benefit from surgical resection. As recommended in the National Institute of Health and Clinical Excellence (NICE) guidelines, magnetic resonance imaging (MRI) is used to screen for structural abnormalities in these patients and there is increasing evidence that 3T MRI has better sensitivity and specificity than 1.5T. This article reviews the imaging findings of many of the common diseases that can cause epilepsy.

  13. A free-breathing non-contrast-enhanced pulmonary magnetic resonance angiography at 3 Tesla

    YANG Jian; WANG Wei; WANG Ya-rong; NIU Gang; JIN Chen-wang; WU Ed Xuekui

    2009-01-01

    Background The breathhold contrast-enhanced three-dimensional magnetic resonance angiography (MRA) using T1-weighted gradient-echo imaging sequence is the standard technique for MRA of the thorax. However, this technique is not desirable for certain patients with respiratory insufficiency, serious renal impairment, or allergy to contrast agents. The objective of this study was to optimize and evaluate a non-contrast-enhanced free-breathing pulmonary MRA protocol at 3 Tesla.Methods The time-of-flight protocol was based on a two-dimensional T1-weighted turbo field echo sequence with slice-selective inversion recovery and magnetization transfer preparation together with respiratory navigator gating, cardiac gating, and parallel imaging. Optimal values for time of inversion delay, flip angle and slice thickness were experimentally determined and used for all subjects.Results Excellent pulmonary MRA images, in which the 7th order branches of pulmonary arteries could be reliably identified, were obtained in the 12 free-breathing healthy volunteers. TI of ~300 ms provides the best suppression of background thoracic and cardiac muscles and effective inflow enhancement. With increasing flip angle, the pulmonary vessels gradually brightened and exhibited optimal contrast at 20°-30°. The 2 mm slice thickness and 0.5 mm slice overlap is suitable for visualization of the peripheral pulmonary vessel.Conclusions The MRA protocol at 3 Tesla may have clinical significance for pulmonary vascular imaging in patients who are not available for contrast-enhanced 3D MRA and CT angiography examination or are unable to sustain a long breath-hold.

  14. Recurrent ulnar nerve entrapment at the elbow: Correlation of surgical findings and 3-Tesla magnetic resonance neurography

    Chhabra, Avneesh; Wadhwa, Vibhor; Thakkar, Rashmi S; John A Carrino; Dellon, A. Lee

    2013-01-01

    The authors describe the correlation between 3-Tesla magnetic resonance neurography (MRN) and surgical findings in two patients who underwent multiple previous failed ulnar nerve surgeries. MRN correctly localized the site of the abnormality. Prospectively observed MRN findings of perineural fibrosis, ulnar nerve re-entrapment abnormalities, medial antebrachial cutaneous neuroma and additional median nerve entrapment were confirmed surgically.

  15. Optimized magnetic resonance sequences and parameters with operative assisted images for radical prostatectomy at 3 tesla-magnetic resonance image

    The objective of our study was to optimize magnetic resonance image (MRI) sequences and parameters using operative assisted images (three-dimensional images) for radical prostatectomy at 3 tesla (T) MRI. Five healthy volunteers underwent MRI on the 3.0 T scanner. Various sequences and parameters [Cube (echo time/repetition time (TE/TR)=18, 50, 90 ms/2000 ms), fast imaging employing steady state acquisition (FIESTA) (TE/TR/FA=2.4 ms/5 ms/40deg, 90deg), fast spoiled gradient recalled acquisition in the steady state (fSPGR) (TE/TR/FA=2.3 ms/11.2 ms/20deg), slice thickness=1.2 mm, matrix=192 x 160] were respectively compared. Several structures of the pelvis (the central zones and transition zones of the prostate, the peripheral zones of the prostate, seminal vesicles, rectum wall, bladder, muscle and fat) were determined. The signal intensities of these structures were measured on reformatted axial images and compared against several structures of the pelvis. Correlation with various sequences and parameters was based on the signal-to-noise ratio (SNR), the contrast ratio (CR) and the presence of artifacts. Student's t-test was used for statistical analysis. With Cube (TE/TR=50 ms/2000 ms), the average value of visual evaluation with artifacts was high, and SNR and CR were higher than for other sequence and parameters. Optimized MRI sequences and parameters were Cube (TE/TR=50 ms/2000 ms) which provides improved SNR and CR and the presence of artifacts with operative assisted images for radical prostatectomy. These operative assisted images obtained from Cube (TE/TR=50 ms/2000 ms) are likely to be useful for surgery. (author)

  16. Magnetic resonance imaging evaluation after implantation of a titanium cervical disc prosthesis: a comparison of 1.5 and 3 Tesla magnet strength

    Sundseth, Jarle; Jacobsen, Eva A.; Kolstad, Frode; Nygaard, Oystein P.; Zwart, John A.; Hol, Per K.

    2013-01-01

    Purpose Cervical disc prostheses induce significant amount of artifact in magnetic resonance imaging which may complicate radiologic follow-up after surgery. The purpose of this study was to investigate as to what extent the artifact, induced by the frequently used Discover® cervical disc prosthesis, impedes interpretation of the MR images at operated and adjacent levels in 1.5 and 3 Tesla MR. Methods Ten subsequent patients were investigated in both 1.5 and 3 Tesla MR with standard image seq...

  17. Comparison of Deep Brain Stimulation Lead Targeting Accuracy and Procedure Duration between 1.5-and 3-Tesla Interventional Magnetic Resonance Imaging Systems: An Initial 12-Month Experience

    Southwell, DG; Narvid, JA; Martin, AJ; Qasim, SE; Starr, PA; Larson, PS

    2016-01-01

    Interventional magnetic resonance imaging (iMRI) allows deep brain stimulator lead placement under general anesthesia. While the accuracy of lead targeting has been described for iMRI systems utilizing 1.5-tesla magnets, a similar assessment of 3-tesla iMRI procedures has not been performed.To compare targeting accuracy, the number of lead targeting attempts, and surgical duration between procedures performed on 1.5- and 3-tesla iMRI systems.Radial targeting error, the number of targeting att...

  18. A review of the safety implications of magnetic resonance imaging at field strengths of 3 Tesla and above

    Rationale: Diagnostic imaging is being driven by technological developments particularly so in the field of Magnetic Resonance Imaging (MRI). Electromagnetic fields used to produce images are becoming much stronger and switched more rapidly and it is essential that safety advice remains appropriate and current. Using a systematic methodology, this review aims to identify the clinical safety implications in performing MRI at field strengths of 3 Tesla (T) and above and determine whether the current clinical safety guidelines are appropriate. Method: References were sourced from The Cochrane Library, Centre for Reviews and Dissemination Science Direct, PubMed and Google Scholar. Related websites searched included The British Institute of Radiology, Society of Radiographers, Royal College of Radiologists, The Institution of Engineering and Technology, IMRSER (Institute for Magnetic Resonance Safety, Education, and Research), MagNet (NHS PASA). References supplied in retrieved papers were also checked for potential relevance. The use of consistent search terminology and inclusion and exclusion criteria ensured quality and provided rigour to conclusions drawn. Conclusion: According to the literature retrieved, the current body of knowledge has allowed safety guidelines to be established for patient safety and these are both appropriate and valid at field strengths of 3 T.

  19. Utility and limitations of 3-Tesla diffusion-weighted magnetic resonance imaging for differentiation of renal tumors

    Sevcenco, S., E-mail: sabina.sevcenco@meduniwien.ac.at [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Heinz-Peer, G., E-mail: gertraud.heinz-peer@meduniwien.ac.at [Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Ponhold, L., E-mail: lothar.ponhold@meduniwien.ac.at [Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Javor, D., E-mail: domagoj.javor@meduniwien.ac.at [Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Kuehhas, F.E., E-mail: frenklin.kuehhas@meduniwien.ac.at [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Klingler, H.C., E-mail: christoph.klingler@meduniwien.ac.at [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Remzi, M., E-mail: mesut.remzi@gmx.at [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Weibl, P., E-mail: peter.weibl@meduniwien.ac.at [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Shariat, S.F., E-mail: sfshariat@gmail.com [Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna (Austria); Baltzer, P.A., E-mail: pascal.baltzer@meduniwien.ac.at [Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna (Austria)

    2014-06-15

    Objective: To investigate utility and limitations of 3-Tesla diffusion-weighted (DW) magnetic resonance imaging (MRI) for differentiation of benign versus malignant renal lesions and renal cell carcinoma (RCC) subtypes. Materials and methods: Sixty patients with 71 renal lesions underwent 3 Tesla DW-MRI of the kidney before diagnostic tissue confirmation. The images were retrospectively evaluated blinded to histology. Single-shot echo-planar imaging was used as the DW imaging technique. Apparent diffusion coefficient (ADC) values were measured and compared with histopathological characteristics. Results: There were 54 malignant and 17 benign lesions, 46 lesions being small renal masses ≤4 cm. Papillary RCC lesions had lower ADC values (p = 0.029) than other RCC subtypes (clear cell or chromophobe). Diagnostic accuracy of DW-MRI for differentiation of papillary from non-papillary RCC was 70.3% resulting in a sensitivity and specificity of 64.3% (95% CI, 35.1–87.2) and 77.1 (95% CI, 59.9–89.6%). Accuracy increased to 83.7% in small renal masses (≤4 cm diameter) and sensitivity and specificity were 75.0% and 88.5%, respectively. The ADC values did not differ significantly between benign and malignant renal lesions (p = 0.45). Conclusions: DW-MRI seems to distinguish between papillary and other subtypes of RCCs especially in small renal masses but could not differentiate between benign and malignant renal lesions. Therefore, the use of DW-MRI for preoperative differentiation of renal lesions is limited.

  20. Utility and limitations of 3-Tesla diffusion-weighted magnetic resonance imaging for differentiation of renal tumors

    Objective: To investigate utility and limitations of 3-Tesla diffusion-weighted (DW) magnetic resonance imaging (MRI) for differentiation of benign versus malignant renal lesions and renal cell carcinoma (RCC) subtypes. Materials and methods: Sixty patients with 71 renal lesions underwent 3 Tesla DW-MRI of the kidney before diagnostic tissue confirmation. The images were retrospectively evaluated blinded to histology. Single-shot echo-planar imaging was used as the DW imaging technique. Apparent diffusion coefficient (ADC) values were measured and compared with histopathological characteristics. Results: There were 54 malignant and 17 benign lesions, 46 lesions being small renal masses ≤4 cm. Papillary RCC lesions had lower ADC values (p = 0.029) than other RCC subtypes (clear cell or chromophobe). Diagnostic accuracy of DW-MRI for differentiation of papillary from non-papillary RCC was 70.3% resulting in a sensitivity and specificity of 64.3% (95% CI, 35.1–87.2) and 77.1 (95% CI, 59.9–89.6%). Accuracy increased to 83.7% in small renal masses (≤4 cm diameter) and sensitivity and specificity were 75.0% and 88.5%, respectively. The ADC values did not differ significantly between benign and malignant renal lesions (p = 0.45). Conclusions: DW-MRI seems to distinguish between papillary and other subtypes of RCCs especially in small renal masses but could not differentiate between benign and malignant renal lesions. Therefore, the use of DW-MRI for preoperative differentiation of renal lesions is limited

  1. Comparison of Pelvic Phased-Array versus Endorectal Coil Magnetic Resonance Imaging at 3 Tesla for Local Staging of Prostate Cancer

    Kim, Bum Soo; Kim, Tae-Hwan; Kwon, Tae Gyun; Yoo, Eun Sang

    2012-01-01

    Purpose Several studies have demonstrated the superiority of endorectal coil magnetic resonance imaging (MRI) over pelvic phased-array coil MRI at 1.5 Tesla for local staging of prostate cancer. However, few have studied which evaluation is more accurate at 3 Tesla MRI. In this study, we compared the accuracy of local staging of prostate cancer using pelvic phased-array coil or endorectal coil MRI at 3 Tesla. Materials and Methods Between January 2005 and May 2010, 151 patients underwent radi...

  2. Physiological effects of cigarette smoking in the limbic system revealed by 3 tesla magnetic resonance spectroscopy.

    Mennecke, Angelika; Gossler, Andrea; Hammen, Thilo; Dörfler, Arnd; Stadlbauer, Andreas; Rösch, Julie; Kornhuber, Johannes; Bleich, Stefan; Dölken, Marc; Thürauf, Norbert

    2014-10-01

    Several studies and recent models of effects of nicotine, the main addictive and psychoactive component in tobacco, point to action of the drug on the limbic system during maintenance of addiction, either direct or indirect via projections from the ventral tegmental area. The objective of this study was to demonstrate physiological effects of cigarette smoking on the hippocampus and the grey matter of the dorsal anterior cingulate cortex in the human brain with regard to addiction and withdrawal. This aim was achieved by group comparisons of results of magnetic resonance spectroscopy between non-smokers, smokers and smokers during withdrawal. 12 smokers and 12 non-smokers were measured with single voxel proton magnetic resonance spectroscopy for total N-acetyl aspartate, glutamate and glutamine, choline-containing compounds, myo-inositol and total creatine in the right and the left hippocampus and in the right and the left dorsal anterior cingulate cortex. Smokers were examined twice, first during regular cigarette smoking and second on the third day of nicotine withdrawal. The ratios to total creatine were used for better reliability. In our study, Glx/tCr was significantly increased and tCho/tCr was significantly decreased in the left cingulate cortex in smokers compared to non-smokers (p = 0.01, both). Six out of seven smokers showed normalization of the Glx/tCr in the left cingulate cortex during withdrawal. Although these results are preliminary due to the small sample size, our results confirm the assumption that cigarette smoking interferes directly or indirectly with the glutamate circuit in the dorsal anterior cingulate cortex. PMID:24643301

  3. White Matter Brain Lesions in Midlife Familial Hypercholesterolemic Patients at 3-Tesla Magnetic Resonance Imaging

    Schmitz, S.A.; O' Regan, D.P.; Fitzpatrick, J.; Neuwirth, C.; Potter, E.; Tosi, I.; Hajnal, J.V.; Naoumova, R.P. (Imaging Sciences Dept. and Clinical Research Facility, MRC Clinical Sciences Centre, London (GB))

    2008-03-15

    Background: Patients with hypercholesterolemia of 60 years and older have an increased risk for white matter brain lesions and dementia. Purpose: To investigate whether patients with familial hypercholesterolemia (FH) develop white matter lesions at 3-Tesla (T) MRI as early as in midlife. Material and Methods: Non-diabetic, non-smoking, and non-hypertensive heterozygous FH patients on treatment with maximally tolerated dose of a statin for more than 5 years (n = 14) and matched controls (n = 22) aged 25 to 60 years of age were studied. Imaging was performed at 3T with a fluid-attenuated T2-weighted MR pulse sequence and a T1-weighted spin-echo pulse sequence following 10 ml of i.v. gadopentetate dimeglumine. Images were evaluated by two independent readers. Fasting blood samples were taken. Student's t test was employed at P<0.05. Results: Three volunteers and one FH patient had white matter lesions (P<0.53). No other evidence of past ischemic stroke was observed. Mean total serum cholesterol and low-density lipoprotein (LDL) cholesterol were significantly higher in the FH group (6.0+-1.1 vs. 5.1+-0.9 mmol/l, P<0.02 and 4.1+-0.9 vs. 3.1+-0.8 mmol/l, P<0.004, respectively). Conclusion: Heterozygous FH patients on statin treatment in the age range of 25 to 60 years are not at increased risk of white matter lesions at 3T MRI

  4. White Matter Brain Lesions in Midlife Familial Hypercholesterolemic Patients at 3-Tesla Magnetic Resonance Imaging

    Background: Patients with hypercholesterolemia of 60 years and older have an increased risk for white matter brain lesions and dementia. Purpose: To investigate whether patients with familial hypercholesterolemia (FH) develop white matter lesions at 3-Tesla (T) MRI as early as in midlife. Material and Methods: Non-diabetic, non-smoking, and non-hypertensive heterozygous FH patients on treatment with maximally tolerated dose of a statin for more than 5 years (n = 14) and matched controls (n = 22) aged 25 to 60 years of age were studied. Imaging was performed at 3T with a fluid-attenuated T2-weighted MR pulse sequence and a T1-weighted spin-echo pulse sequence following 10 ml of i.v. gadopentetate dimeglumine. Images were evaluated by two independent readers. Fasting blood samples were taken. Student's t test was employed at P<0.05. Results: Three volunteers and one FH patient had white matter lesions (P<0.53). No other evidence of past ischemic stroke was observed. Mean total serum cholesterol and low-density lipoprotein (LDL) cholesterol were significantly higher in the FH group (6.0±1.1 vs. 5.1±0.9 mmol/l, P<0.02 and 4.1±0.9 vs. 3.1±0.8 mmol/l, P<0.004, respectively). Conclusion: Heterozygous FH patients on statin treatment in the age range of 25 to 60 years are not at increased risk of white matter lesions at 3T MRI

  5. Differences in Velopharyngeal Structure during Speech among Asians Revealed by 3-Tesla Magnetic Resonance Imaging Movie Mode

    Kulthida Nunthayanon

    2015-01-01

    Full Text Available Objective. Different bony structures can affect the function of the velopharyngeal muscles. Asian populations differ morphologically, including the morphologies of their bony structures. The purpose of this study was to compare the velopharyngeal structures during speech in two Asian populations: Japanese and Thai. Methods. Ten healthy Japanese and Thai females (five each were evaluated with a 3-Tesla (3 T magnetic resonance imaging (MRI scanner while they produced vowel-consonant-vowel syllable (/asa/. A gradient-echo sequence, fast low-angle shot with segmented cine and parallel imaging technique was used to obtain sagittal images of the velopharyngeal structures. Results. MRI was carried out in real time during speech production, allowing investigations of the time-to-time changes in the velopharyngeal structures. Thai subjects had a significantly longer hard palate and produced shorter consonant than Japanese subjects. The velum of the Thai participants showed significant thickening during consonant production and their retroglossal space was significantly wider at rest, whereas the dimensional change during task performance was similar in the two populations. Conclusions. The 3 T MRI movie method can be used to investigate velopharyngeal function and diagnose velopharyngeal insufficiency. The racial differences may include differences in skeletal patterns and soft-tissue morphology that result in functional differences for the affected structures.

  6. 3 tesla magnetic resonance imaging in children and adults with congenital heart disease; 3-Tesla-Magnetresonanztomographie zur Untersuchung von Kindern und Erwachsenen mit angeborenen Herzfehlern

    Voges, I.; Hart, C.; Kramer, H.H.; Rickers, C. [Universitaetsklinikum Schleswig-Holstein, Klinik fuer angeborene Herzfehler und Kinderkardiologie, Kiel (Germany); Jerosch-Herold, M. [Harvard Medical School, Department of Radiology, Brigham and Women' s Hospital, Boston (United States); Helle, M. [Universitaetsklinikum Schleswig-Holstein, Institut fuer Neuroradiologie, Kiel (Germany)

    2010-09-15

    Cardiovascular magnetic resonance imaging (CMR) has become a routinely used imaging modality for congenital heart disease. A CMR examination allows the assessment of thoracic anatomy, global and regional cardiac function, blood flow in the great vessels and myocardial viability and perfusion. In the clinical routine cardiovascular MRI is mostly performed at field strengths of 1.5 Tesla (T). Recently, magnetic resonance systems operating at a field strengths of 3 T became clinically available and can also be used for cardiovascular MRI. The main advantage of CMR at 3 T is the gain in the signal-to-noise ratio resulting in improved image quality and/or allowing higher acquisition speed. Several further differences compared to MRI systems with lower field strengths have to be considered for practical applications. This article describes the impact of CMR at 3 T in patients with congenital heart disease by meanings of methodical considerations and case studies. (orig.) [German] Die kardiovaskulaere Magnetresonanztomographie (MRT) hat sich zu einer etablierten bildgebenden Methode zur Untersuchung von Patienten mit angeborenen Herzfehlern entwickelt. Sie erlaubt in einer einzigen Untersuchung die exakte Beurteilung von Anatomie, globaler und regionaler Funktion, Blutfluessen sowie der myokardialen Perfusion und Vitalitaet. In der klinischen Routine erfolgen die Untersuchungen zumeist bei einer Feldstaerke von 1,5 Tesla (T), mittlerweile gibt es jedoch Geraete und Bildgebungstechniken, die die kardiovaskulaere MRT auch bei 3 T ermoeglichen. Der wesentliche Vorteil der MRT bei 3 T ist das hoehere Signal-zu-Rausch-Verhaeltnis, das sowohl zu einer Verbesserung der Bildqualitaet als auch zu einer Verkuerzung der Untersuchungszeit genutzt werden kann. Darueber hinaus bestehen verschiedene andere Unterschiede gegenueber Systemen mit niedriger Feldstaerke, die im praktischen Einsatz beachtet werden muessen. Dieser Artikel beschreibt die Erfahrungen der 3-T-MRT fuer die

  7. Fetal magnetic resonance imaging: jumping from 1.5 to 3 tesla (preliminary experience)

    Victoria, Teresa [The Children' s Hospital of Philadelphia, Radiology Department, Center for Fetal Diagnosis and Treatment, Philadelphia, PA (United States); Jaramillo, Diego; Roberts, Timothy Paul Leslie; Zarnow, Deborah; Johnson, Ann Michelle; Delgado, Jorge; Vossough, Arastoo [The Children' s Hospital of Philadelphia, Radiology Department, Philadelphia, PA (United States); Rubesova, Erika [Stanford University, Department of Radiology, Lucile Packard Children' s Hospital, Stanford, CA (United States)

    2014-04-15

    Several attempts have been made at imaging the fetus at 3 T as part of the continuous search for increased image signal and better anatomical delineation of the developing fetus. Until very recently, imaging of the fetus at 3 T has been disappointing, with numerous artifacts impeding image analysis. Better magnets and coils and improved technology now allow imaging of the fetus at greater magnetic strength, some hurdles in the shape of imaging artifacts notwithstanding. In this paper we present the preliminary experience of evaluating the developing fetus at 3 T and discuss several artifacts encountered and techniques to decrease them, as well as safety concerns associated with scanning the fetus at higher magnetic strength. (orig.)

  8. Hepatic Iron Quantification on 3 Tesla (3 T) Magnetic Resonance (MR): Technical Challenges and Solutions

    MR has become a reliable and noninvasive method of hepatic iron quantification. Currently, most of the hepatic iron quantification is performed on 1.5 T MR, and the biopsy measurements have been paired with R2 and R2* values for 1.5 T MR. As the use of 3 T MR scanners is steadily increasing in clinical practice, it has become important to evaluate the practicality of calculating iron burden at 3 T MR. Hepatic iron quantification on 3 T MR requires a better understanding of the process and more stringent technical considerations. The purpose of this work is to focus on the technical challenges in establishing a relationship between T2* values at 1.5 T MR and 3 T MR for hepatic iron concentration (HIC) and to develop an appropriately optimized MR protocol for the evaluation of T2* values in the liver at 3 T magnetic field strength. We studied 22 sickle cell patients using multiecho fast gradient-echo sequence (MFGRE) 3 T MR and compared the results with serum ferritin and liver biopsy results. Our study showed that the quantification of hepatic iron on 3 T MRI in sickle cell disease patients correlates well with clinical blood test results and biopsy results. 3 T MR liver iron quantification based on MFGRE can be used for hepatic iron quantification in transfused patients

  9. Hepatic Iron Quantification on 3 Tesla (3 T) Magnetic Resonance (MR): Technical Challenges and Solutions

    MR has become a reliable and noninvasive method of hepatic iron quantification. Currently, most of the hepatic iron quantification is performed on 1.5 T MR, and the biopsy measurements have been paired withR2 and R2∗ values for 1.5 T MR. As the use of 3 T MR scanners is steadily increasing in clinical practice, it has become important to evaluate the practicality of calculating iron burden at 3 T MR. Hepatic iron quantification on 3 T MR requires a better understanding of the process and more stringent technical considerations. The purpose of this work is to focus on the technical challenges in establishing a relationship between T2 ∗ values at 1.5 T MR and 3 T MR for hepatic iron concentration (HIC) and to develop an appropriately optimized MR protocol for the evaluation of T2 ∗ values in the liver at 3 T magnetic field strength. We studied 22 sickle cell patients using multiecho fast gradient-echo sequence (MFGRE) 3 T MR and compared the results with serum ferritin and liver biopsy results. Our study showed that the quantification of hepatic iron on 3 T MRI in sickle cell disease patients correlates well with clinical blood test results and biopsy results. 3 T MR liver iron quantification based on MFGRE can be used for hepatic iron quantification in transfused patients.

  10. Diagnostic accuracy of a short-duration 3 Tesla magnetic resonance protocol for diagnosing stifle joint lesions in dogs with non-traumatic cranial cruciate ligament rupture

    Galindo-Zamora, Vladimir; Dziallas, Peter; Ludwig, Davina C; Nolte, Ingo; Wefstaedt, Patrick

    2013-01-01

    Background Magnetic resonance (MR) imaging is the preferred diagnostic tool to evaluate internal disorders of many joints in humans; however, the usefulness of MR imaging in the context of osteoarthritis, and joint disease in general, has yet to be characterized in veterinary medicine. The objective of this study was to assess the diagnostic accuracy of short-duration 3 Tesla MR imaging for the evaluation of cranial and caudal cruciate ligament, meniscal and cartilage damage, as well as the d...

  11. High-Resolution Magnetic Resonance Imaging of Trabecular Bone in the Wrist at 3 Tesla: Initial Results

    Ludescher, B.; Martirosian, P.; Lenk, S.; Machann, J.; Dammann, F.; Schick, F.; Claussen, C.; Schlemmer, H. [Univ. Clinic, Tuebingen (Germany). Dept. of Diagnostic Radiology and Section on Experimental Radiology

    2005-05-01

    Purpose: To evaluate the feasibility of high-resolution magnetic resonance imaging (MRI) of trabecular bone of the wrist at 3 Tesla (3T) in vivo and to assess the potential benefit of the increased resolution for clinical assessment of structural changes in spongy bone. Material and Methods: High-resolution MRI of the wrist was performed with a whole-body 3T MR scanner using a dedicated circularly polarized transmit/receive wrist-coil. Two 3D-FISP sequences with a spatial resolution of 300x300x300 {mu}m{sup 3} in a measuring time of TA{approx}7:51 min, and 200x200x200 {mu}m{sup 3} in TA{approx}9:33 min were applied. Seven young healthy volunteers and three elderly subjects with suspected osteoporosis were examined. The signal-to-noise ratio (SNR) in the optimized setup at 3T was compared to measurements at 1.5T. Results: The images at 3T allow microscopic analysis of the bone structure at an isotropic spatial resolution of 200 {mu}m in examination times of <10 min. Differences in the structure of the spongy bone between normal and markedly osteoporotic subjects are well depicted. The SNR at 3T was found up to 16 times higher than at 1.5T applying unchanged imaging parameters. Conclusion: The proposed high-resolution MRI technique offers high potential in the diagnosis and follow-up of diseases with impaired bone structure of hand and/or wrist in clinical applications.

  12. High resolution T{sub 2}{sup *}-weighted magnetic resonance imaging at 3 Tesla using PROPELLER-EPI

    Kraemer, Martin; Reichenbach, Juergen R. [Jena University Hospital (Germany). Medical Physics Group

    2014-09-01

    We report the application of PROPELLER-EPI for high resolution T{sub 2}{sup *}-weighted imaging with sub-millimeter in-plane resolution on a clinical 3 Tesla scanner. Periodically rotated blades of a long-axis PROPELLER-EPI sequence were acquired with fast gradient echo readout and acquisition matrix of 320 x 50 per blade. Images were reconstructed by using 2D-gridding, phase and geometric distortion correction and compensation of resonance frequency drifts that occurred during extended measurements. To characterize these resonance frequency offsets, short FID calibration measurements were added to the PROPELLER-EPI sequence. Functional PROPELLER-EPI was performed with volunteers using a simple block design of right handed finger tapping. Results indicate that PROPELLER-EPI can be employed for fast, high resolution T{sub 2}{sup *}-weighted imaging provided geometric distortions and possible resonance frequency drifts are properly corrected. Even small resonance frequency drifts below 10 Hz as well as non-corrected geometric distortions degraded image quality substantially. In the initial fMRI experiment image quality and signal-to-noise ratio was sufficient for obtaining high resolution functional activation maps. (orig.)

  13. Whole-body magnetic resonance angiography at 3 tesla using a hybrid protocol in patients with peripheral arterial disease

    Nielsen, Yousef W; Eiberg, Jonas P; Logager, Vibeke B;

    2009-01-01

    The purpose of this study was to determine the diagnostic performance of 3T whole-body magnetic resonance angiography (WB-MRA) using a hybrid protocol in comparison with a standard protocol in patients with peripheral arterial disease (PAD). In 26 consecutive patients with PAD two different proto...

  14. Volume and Asymmetry Abnormalities of Insula in Antipsychotic-Naive Schizophrenia: A 3-Tesla Magnetic Resonance Imaging Study

    Harve Shanmugam Virupaksha; Kalmady, Sunil V.; Venkataram Shivakumar; Rashmi Arasappa; Ganesan Venkatasubramanian; Bangalore N Gangadhar

    2012-01-01

    Context: Insula, which is a vital brain region for self-awareness, empathy, and sensory stimuli processing, is critically implicated in schizophrenia pathogenesis. Existing studies on insula volume abnormalities report inconsistent findings potentially due to the evaluation of ′antipsychotic-treated′ schizophrenia patients as well as suboptimal methodology. Aim: To understand the role of insula in schizophrenia. Materials and Methods: In this first-time 3-T magnetic resonance imaging study, w...

  15. Investigation of Parallel Radiofrequency Transmission for the Reduction of Heating in Long Conductive Leads in 3 Tesla Magnetic Resonance Imaging

    McElcheran, Clare E.; Yang, Benson; Anderson, Kevan J. T.; Golenstani-Rad, Laleh; Graham, Simon J

    2015-01-01

    Deep Brain Stimulation (DBS) is increasingly used to treat a variety of brain diseases by sending electrical impulses to deep brain nuclei through long, electrically conductive leads. Magnetic resonance imaging (MRI) of patients pre- and post-implantation is desirable to target and position the implant, to evaluate possible side-effects and to examine DBS patients who have other health conditions. Although MRI is the preferred modality for pre-operative planning, MRI post-implantation is limi...

  16. 3 Tesla magnetic resonance spectroscopy: cerebral gliomas vs. metastatic brain tumors. Our experience and review of the literature.

    Caivano, R; Lotumolo, A; Rabasco, P; Zandolino, A; D'Antuono, F; Villonio, A; Lancellotti, M I; Macarini, L; Cammarota, A

    2013-08-01

    The aim of the present study is to report about the value of magnetic resonance spectroscopy (MRS) in differentiating brain metastases, primary high-grade gliomas (HGG) and low-grade gliomas (LGG). MRI (magnetic resonance imaging) and MRS were performed in 60 patients with histologically verified brain tumors: 32 patients with HGG (28 glioblastomas multiforme [GBM] and 4 anaplastic astrocytomas), 14 patients with LGG (9 astrocytomas and 5 oligodendrogliomas) and 14 patients with metastatic brain tumors. The Cho/Cr (choline-containing compounds/creatine-phosphocreatine complex), Cho/NAA (N-acetyl aspartate) and NAA/Cr ratios were assessed from spectral maps in the tumoral core and peritumoral edema. The differences in the metabolite ratios between LGG, HGG and metastases were analyzed statistically. Lipids/lactate contents were also analyzed. Significant differences were noted in the tumoral and peritumoral Cho/Cr, Cho/NAA and NAA/Cr ratios between LGG, HGG and metastases. Lipids and lactate content revealed to be useful for discriminating gliomas and metastases. The results of this study demonstrate that MRS can differentiate LGG, HGG and metastases, therefore diagnosis could be allowed even in those patients who cannot undergo biopsy. PMID:23390934

  17. Investigation of Parallel Radiofrequency Transmission for the Reduction of Heating in Long Conductive Leads in 3 Tesla Magnetic Resonance Imaging.

    Clare E McElcheran

    Full Text Available Deep Brain Stimulation (DBS is increasingly used to treat a variety of brain diseases by sending electrical impulses to deep brain nuclei through long, electrically conductive leads. Magnetic resonance imaging (MRI of patients pre- and post-implantation is desirable to target and position the implant, to evaluate possible side-effects and to examine DBS patients who have other health conditions. Although MRI is the preferred modality for pre-operative planning, MRI post-implantation is limited due to the risk of high local power deposition, and therefore tissue heating, at the tip of the lead. The localized power deposition arises from currents induced in the leads caused by coupling with the radiofrequency (RF transmission field during imaging. In the present work, parallel RF transmission (pTx is used to tailor the RF electric field to suppress coupling effects. Electromagnetic simulations were performed for three pTx coil configurations with 2, 4, and 8-elements, respectively. Optimal input voltages to minimize coupling, while maintaining RF magnetic field homogeneity, were determined for all configurations using a Nelder-Mead optimization algorithm. Resulting electric and magnetic fields were compared to that of a 16-rung birdcage coil. Experimental validation was performed with a custom-built 4-element pTx coil. In simulation, 95-99% reduction of the electric field at the tip of the lead was observed between the various pTx coil configurations and the birdcage coil. Maximal reduction in E-field was obtained with the 8-element pTx coil. Magnetic field homogeneity was comparable to the birdcage coil for the 4- and 8-element pTx configurations. In experiment, a temperature increase of 2±0.15°C was observed at the tip of the wire using the birdcage coil, whereas negligible increase (0.2±0.15°C was observed with the optimized pTx system. Although further research is required, these initial results suggest that the concept of optimizing p

  18. Volume and asymmetry abnormalities of insula in antipsychotic-naive schizophrenia: A 3-Tesla magnetic resonance imaging study

    Harve Shanmugam Virupaksha

    2012-01-01

    Full Text Available Context: Insula, which is a vital brain region for self-awareness, empathy, and sensory stimuli processing, is critically implicated in schizophrenia pathogenesis. Existing studies on insula volume abnormalities report inconsistent findings potentially due to the evaluation of ′antipsychotic-treated′ schizophrenia patients as well as suboptimal methodology. Aim: To understand the role of insula in schizophrenia. Materials and Methods: In this first-time 3-T magnetic resonance imaging study, we examined antipsychotic-naive schizophrenic patients (N=30 and age-, sex-, handedness- and education-matched healthy controls (N=28. Positive and negative symptoms were scored with good interrater reliability (intraclass correlation coefficient (ICC>0.9 by using the scales for negative and positive symptoms. Gray matter volume of insula and its anterior/posterior subregions were measured by using a three-dimensional, interactive, semiautomated software based on the valid method with good interrater reliability (ICC>0.85. Intracranial volume was automatically measured by using the FreeSurfer software. Results: Patients had significantly deficient gray matter volumes of left (F=33.4; Pleft in male patients in comparison with male controls (left>right (t=2.7; P=0.01. Conclusions: Robust insular volume deficits in antipsychotic-naive schizophrenia support intrinsic role for insula in pathogenesis of this disorder. The first-time demonstration of a relationship between right posterior insular deficit and negative symptoms is in tune with the background neurobiological literature. Another novel observation of sex-specific anterior insular asymmetry reversal in patients supports evolutionary postulates of schizophrenia pathogenesis.

  19. Hepatic Iron Quantification on 3 Tesla (3 T Magnetic Resonance (MR: Technical Challenges and Solutions

    Muhammad Anwar

    2013-01-01

    Full Text Available MR has become a reliable and noninvasive method of hepatic iron quantification. Currently, most of the hepatic iron quantification is performed on 1.5 T MR, and the biopsy measurements have been paired with R2 and R2* values for 1.5 T MR. As the use of 3 T MR scanners is steadily increasing in clinical practice, it has become important to evaluate the practicality of calculating iron burden at 3 T MR. Hepatic iron quantification on 3 T MR requires a better understanding of the process and more stringent technical considerations. The purpose of this work is to focus on the technical challenges in establishing a relationship between T2* values at 1.5 T MR and 3 T MR for hepatic iron concentration (HIC and to develop an appropriately optimized MR protocol for the evaluation of T2* values in the liver at 3 T magnetic field strength. We studied 22 sickle cell patients using multiecho fast gradient-echo sequence (MFGRE 3 T MR and compared the results with serum ferritin and liver biopsy results. Our study showed that the quantification of hepatic iron on 3 T MRI in sickle cell disease patients correlates well with clinical blood test results and biopsy results. 3 T MR liver iron quantification based on MFGRE can be used for hepatic iron quantification in transfused patients.

  20. A comparison between magnetic resonance angiography at 3 teslas (time-of-flight and contrast-enhanced and flat-panel digital subtraction angiography in the assessment of embolized brain aneurysms

    Guilherme S. Nakiri

    2011-01-01

    Full Text Available PURPOSE: To compare the time-of-flight and contrast-enhanced- magnetic resonance angiography techniques in a 3 Tesla magnetic resonance unit with digital subtraction angiography with the latest flat-panel technology and 3D reconstruction in the evaluation of embolized cerebral aneurysms. INTRODUCTION: Many embolized aneurysms are subject to a recurrence of intra-aneurismal filling. Traditionally, imaging surveillance of coiled aneurysms has consisted of repeated digital subtraction angiography. However, this method has a small but significant risk of neurological complications, and many authors have advocated the use of noninvasive imaging methods for the surveillance of embolized aneurysms. METHODS: Forty-three aneurysms in 30 patients were studied consecutively between November 2009 and May 2010. Two interventional neuroradiologists rated the time-of-flight-magnetic resonance angiography, the contrast-enhanced-magnetic resonance angiography, and finally the digital subtraction angiography, first independently and then in consensus. The status of aneurysm occlusion was assessed according to the Raymond scale, which indicates the level of recanalization according to degrees: Class 1: excluded aneurysm; Class 2: persistence of a residual neck; Class 3: persistence of a residual aneurysm. The agreement among the analyses was assessed by applying the Kappa statistic. RESULTS: Inter-observer agreement was excellent for both methods (K = 0.93; 95 % CI: 0.84-1. Inter-technical agreement was almost perfect between time-of-flight-magnetic resonance angiography and digital subtraction angiography (K = 0.98; 95 % CI: 0.93-1 and between time-of-flight-magnetic resonance angiography and contrast-enhanced-magnetic resonance angiography (K = 0.98; 95% CI: 0.93-1. Disagreement occurred in only one case (2.3%, which was classified as Class I by time-of-flight-magnetic resonance angiography and Class II by digital subtraction angiography. The agreement between

  1. A comparison between magnetic resonance angiography at 3 teslas (time-of-flight and contrast-enhanced) and flat-panel digital subtraction angiography in the assessment of embolized brain aneurysms

    Purpose: to compare the time-of-flight and contrast-enhanced- magnetic resonance angiography techniques in a 3 Tesla magnetic resonance unit with digital subtraction angiography with the latest flat-panel technology and 3D reconstruction in the evaluation of embolized cerebral aneurysms. Introduction: many embolized aneurysms are subject to a recurrence of intra-aneurysmal filling. Traditionally, imaging surveillance of coiled aneurysms has consisted of repeated digital subtraction angiography. However, this method has a small but significant risk of neurological complications, and many authors have advocated the use of noninvasive imaging methods for the surveillance of embolized aneurysms. Methods: forty-three aneurysms in 30 patients were studied consecutively between November 2009 and May 2010. Two interventional neuro radiologists rated the time-of-flight-magnetic resonance angiography, the contrast enhanced-magnetic resonance angiography, and finally the digital subtraction angiography, first independently and then in consensus. The status of aneurysm occlusion was assessed according to the Raymond scale, which indicates the level of recanalization according to degrees: Class 1: excluded aneurysm; Class 2: persistence of a residual neck; Class 3: persistence of a residual aneurysm. The agreement among the analyses was assessed by applying the Kappa statistic. Results: inter-observer agreement was excellent for both methods (K = 0.93; 95 % CI: 0.84-1). Inter-technical agreement was almost perfect between time-of-flight-magnetic resonance angiography and digital subtraction angiography (K = 0.98; 95 % CI: 0.93-1) and between time-of-flight-magnetic resonance angiography and contrast enhanced-magnetic resonance angiography (K = 0.98; 95% CI: 0.93-1). Disagreement occurred in only one case (2.3%), which was classified as Class I by time-of-flight-magnetic resonance angiography and Class II by digital subtraction angiography. The agreement between contrast-enhanced-magnetic

  2. Inter-study reproducibility of arterial spin labelling magnetic resonance imaging for measurement of renal perfusion in healthy volunteers at 3 Tesla

    Gillis, Keith A.; McComb, Christie; Foster, John E.; Taylor, Alison; Patel, Rajan K.; Morris, Scott; Alan G. Jardine; Schneider, Markus P; Roditi, Giles H; Delles, Christian; Mark, Patrick B.

    2014-01-01

    Background: Measurement of renal perfusion is a crucial part of measuring kidney function. Arterial spin labelling magnetic resonance imaging (ASL MRI) is a non-invasive method of measuring renal perfusion using magnetised blood as endogenous contrast. We studied the reproducibility of ASL MRI in normal volunteers. Methods: ASL MRI was performed in healthy volunteers on 2 occasions using a 3.0 Tesla MRI scanner with flow-sensitive alternating inversion recovery (FAIR) perfusion prep...

  3. Assessment of Safety and Interference Issues of Radio Frequency Identification Devices in 0.3 Tesla Magnetic Resonance Imaging and Computed Tomography

    Periyasamy, M.; Dhanasekaran, R.

    2014-01-01

    The objective of this study was to evaluate two issues regarding magnetic resonance imaging (MRI) including device functionality and image artifacts for the presence of radio frequency identification devices (RFID) in association with 0.3 Tesla at 12.7 MHz MRI and computed tomography (CT) scanning. Fifteen samples of RFID tags with two different sizes (wristband and ID card types) were tested. The tags were exposed to several MR-imaging conditions during MRI examination and X-rays of CT scan....

  4. Interdependencies of aortic arch secondary flow patterns, geometry, and age analysed by 4-dimensional phase contrast magnetic resonance imaging at 3 Tesla

    It was the aim to analyse the impact of age, aortic arch geometry, and size on secondary flow patterns such as helix and vortex flow derived from flow-sensitive magnetic resonance imaging (4D PC-MRI). 62 subjects (age range = 20-80 years) without circumscribed pathologies of the thoracic aorta (ascending aortic (AAo) diameter: 3.2 ± 0.6 cm [range 2.2-5.1]) were examined by 4D PC-MRI after IRB-approval and written informed consent. Blood flow visualisation based on streamlines and time-resolved 3D particle traces was performed. Aortic diameter, shape (gothic, crook-shaped, cubic), angle, and age were correlated with existence and extent of secondary flow patterns (helicity, vortices); statistical modelling was performed. Helical flow was the typical pattern in standard crook-shaped aortic arches. With altered shapes and increasing age, helicity was less common. AAo diameter and age had the highest correlation (r = 0.69 and 0.68, respectively) with number of detected vortices. None of the other arch geometric or demographic variables (for all, P ≥ 0.177) improved statistical modelling. Substantially different secondary flow patterns can be observed in the normal thoracic aorta. Age and the AAo diameter were the parameters correlating best with presence and amount of vortices. Findings underline the importance of age- and geometry-matched control groups for haemodynamic studies. (orig.)

  5. Assessment of Safety and Interference Issues of Radio Frequency Identification Devices in 0.3 Tesla Magnetic Resonance Imaging and Computed Tomography

    M. Periyasamy

    2014-01-01

    Full Text Available The objective of this study was to evaluate two issues regarding magnetic resonance imaging (MRI including device functionality and image artifacts for the presence of radio frequency identification devices (RFID in association with 0.3 Tesla at 12.7 MHz MRI and computed tomography (CT scanning. Fifteen samples of RFID tags with two different sizes (wristband and ID card types were tested. The tags were exposed to several MR-imaging conditions during MRI examination and X-rays of CT scan. Throughout the test, the tags were oriented in three different directions (axial, coronal, and sagittal relative to MRI system in order to cover all possible situations with respect to the patient undergoing MRI and CT scanning, wearing a RFID tag on wrist. We observed that the tags did not sustain physical damage with their functionality remaining unaffected even after MRI and CT scanning, and there was no alternation in previously stored data as well. In addition, no evidence of either signal loss or artifact was seen in the acquired MR and CT images. Therefore, we can conclude that the use of this passive RFID tag is safe for a patient undergoing MRI at 0.3 T/12.7 MHz and CT Scanning.

  6. Dapsone improves functional deficit and diminishes brain damage evaluated by 3-Tesla magnetic resonance image after transient cerebral ischemia and reperfusion in rats.

    Diaz-Ruiz, Araceli; Roldan-Valadez, Ernesto; Ortiz-Plata, Alma; Mondragón-Lozano, Rodrigo; Heras-Romero, Yessica; Mendez-Armenta, Marisela; Osorio-Rico, Laura; Nava-Ruiz, Concepción; Ríos, Camilo

    2016-09-01

    Stroke is a frequent cause of death and the first of disability in the world population. We have shown that dapsone acts as an antioxidant, antiinflammatory and antiapoptotic agent after brain Ischemia reperfusion (I/R) in rats; however, its therapeutic efficacy, measured by imaging has not been characterized. In this context, the aim of this study was to evaluate the neuroprotective effect of dapsone by magnetic resonance imaging (MRI) and to correlate imaging markers with motor function and oxidative stress after transient cerebral ischemia and reperfusion (I/R). We used male rats throughout the experiment. Functional deficit after I/R was assessed by using Longa scale. The area of brain tissue damage was measured by histology. The nuclear factor erythroid 2-related factor 2 (Nrf-2) and the amount of reactive oxygen species (ROS) were measured as biomarkers of oxidative stress. Finally, difussion tensor MRI was employed to measure the fractional anisotropy (FA), as a MRI marker of the pathophysiologic brain status. Results showed a better functional recovery and less damaged tissue in animals treated with dapsone vs control group. The values of FA were higher in animals receiving treatment, indicating a better preservation of brain structure. At early stages of the damage, dapsone was able to reduce both oxidative markers (Nrf-2 and ROS). Our findings provide new evidence for the efficacy of dapsone when administered during the acute phase after I/R and that quantitative sequences of MRI are useful for characterizing its potential therapeutic benefits after stroke. PMID:27321157

  7. Interdependencies of aortic arch secondary flow patterns, geometry, and age analysed by 4-dimensional phase contrast magnetic resonance imaging at 3 Tesla

    Frydrychowicz, Alex [University Hospital Schleswig-Holstein, Clinic for Radiology and Nuclear Medicine, Luebeck (Germany); Berger, Alexander; Russe, Maximilian F.; Bock, Jelena [University Hospital Freiburg, Department of Radiology, Medical Physics, Freiburg (Germany); Munoz del Rio, Alejandro [University of Wisconsin - Madison, Departments of Radiology and Medical Physics, Madison, WI (United States); Harloff, Andreas [University Hospital Freiburg, Department of Neurology and Clinical Neurophysiology, Freiburg (Germany); Markl, Michael [University Hospital Freiburg, Department of Radiology, Medical Physics, Freiburg (Germany); Northwestern University, Departments of Radiology and Biomedical Engineering, Chicago, IL (United States)

    2012-05-15

    It was the aim to analyse the impact of age, aortic arch geometry, and size on secondary flow patterns such as helix and vortex flow derived from flow-sensitive magnetic resonance imaging (4D PC-MRI). 62 subjects (age range = 20-80 years) without circumscribed pathologies of the thoracic aorta (ascending aortic (AAo) diameter: 3.2 {+-} 0.6 cm [range 2.2-5.1]) were examined by 4D PC-MRI after IRB-approval and written informed consent. Blood flow visualisation based on streamlines and time-resolved 3D particle traces was performed. Aortic diameter, shape (gothic, crook-shaped, cubic), angle, and age were correlated with existence and extent of secondary flow patterns (helicity, vortices); statistical modelling was performed. Helical flow was the typical pattern in standard crook-shaped aortic arches. With altered shapes and increasing age, helicity was less common. AAo diameter and age had the highest correlation (r = 0.69 and 0.68, respectively) with number of detected vortices. None of the other arch geometric or demographic variables (for all, P {>=} 0.177) improved statistical modelling. Substantially different secondary flow patterns can be observed in the normal thoracic aorta. Age and the AAo diameter were the parameters correlating best with presence and amount of vortices. Findings underline the importance of age- and geometry-matched control groups for haemodynamic studies. (orig.)

  8. Regional Metabolic Changes in the Hippocampus and Posterior Cingulate Area Detected with 3-Tesla Magnetic Resonance Spectroscopy in Patients with Mild Cognitive Impairment and Alzheimer Disease

    Zhiqun Wang; Cheng Zhao; Kuncheng Li (Dept. of Radiology, Xuanwu Hospital, Capital Medical Univ., Beijing (China)); Lei Yu; Weidong Zhou (Dept. of Neurology, Xuanwu Hospital, Capital Medical Univ., Beijing (China))

    2009-04-15

    Background: Magnetic resonance spectroscopy (MRS) plays an important role in early diagnosis of Alzheimer disease (AD). There are many reports on MRS studies among individuals with AD and mild cognitive impairment (MCI). However, very few studies have compared spectroscopic data of different limbic regions among AD and MCI subjects. Purpose: To compare metabolite changes of different regions in the brain of AD and MCI patients by using 3.0T short-echo-time MRS. Material and Methods: Metabolite ratios in the hippocampus and posterior cingulate area were compared in a group of patients with AD (n=16), MCI (n=16), and normal subjects as a control group (n=16). Clinical neuropsychological tests were measured in all subjects. Results: In the hippocampus, there were significant differences in N-acetylaspartate (NAA)/creatine (Cr), myo-inositol (mI)/Cr, and mI/NAA ratios among the three groups. However, there were no significant differences in choline (Cho)/Cr ratio among the three groups. In the posterior cingulate area, there were no significant differences in the NAA/Cr, Cho/Cr, and mI/Cr ratios among the three groups. However, there were significant differences in mI/NAA ratio between patients with AD and the control group, and between the AD and MCI groups. In addition, there was significant correlation between mI/NAA ratio and Mini Mental Status Exam (MMSE) score in subjects with AD and MCI. Conclusion: The study reveals that the elevation of mI/NAA ratio in the hippocampus is more significant than that in the posterior cingulate area, which corresponds to the pathologic procession of AD. The ratios of mI/NAA in the hippocampus and in the posterior cingulate area together provide valuable discrimination among the three groups (AD, MCI, and controls). There is a significant correlation between mI/NAA ratio and cognitive decline.

  9. Regional Metabolic Changes in the Hippocampus and Posterior Cingulate Area Detected with 3-Tesla Magnetic Resonance Spectroscopy in Patients with Mild Cognitive Impairment and Alzheimer Disease

    Background: Magnetic resonance spectroscopy (MRS) plays an important role in early diagnosis of Alzheimer disease (AD). There are many reports on MRS studies among individuals with AD and mild cognitive impairment (MCI). However, very few studies have compared spectroscopic data of different limbic regions among AD and MCI subjects. Purpose: To compare metabolite changes of different regions in the brain of AD and MCI patients by using 3.0T short-echo-time MRS. Material and Methods: Metabolite ratios in the hippocampus and posterior cingulate area were compared in a group of patients with AD (n=16), MCI (n=16), and normal subjects as a control group (n=16). Clinical neuropsychological tests were measured in all subjects. Results: In the hippocampus, there were significant differences in N-acetylaspartate (NAA)/creatine (Cr), myo-inositol (mI)/Cr, and mI/NAA ratios among the three groups. However, there were no significant differences in choline (Cho)/Cr ratio among the three groups. In the posterior cingulate area, there were no significant differences in the NAA/Cr, Cho/Cr, and mI/Cr ratios among the three groups. However, there were significant differences in mI/NAA ratio between patients with AD and the control group, and between the AD and MCI groups. In addition, there was significant correlation between mI/NAA ratio and Mini Mental Status Exam (MMSE) score in subjects with AD and MCI. Conclusion: The study reveals that the elevation of mI/NAA ratio in the hippocampus is more significant than that in the posterior cingulate area, which corresponds to the pathologic procession of AD. The ratios of mI/NAA in the hippocampus and in the posterior cingulate area together provide valuable discrimination among the three groups (AD, MCI, and controls). There is a significant correlation between mI/NAA ratio and cognitive decline

  10. Monitoring of gadolinium-BOPTA uptake into the vessel wall during magnetic resonance (MR)-guided angioplasty of the peripheral arteries with a paclitaxel/gadolinium-BOPTA-coated balloon. An experimental study at 3 Tesla

    Purpose: The success of paclitaxel distribution within the vessel wall during paclitaxel-coated balloon angioplasty to prevent restenosis cannot be monitored under X-ray guidance. The aim of this pilot study was to demonstrate the feasibility of monitoring Gadolinium-BOPTA delivery within the vessel wall during magnetic resonance (MR)-guided paclitaxel/Gadolinium-BOPTA-coated balloon angioplasty of the peripheral arteries. Materials and methods: 6 pigs (47 ± 2 kg) were investigated. All experiments were performed using a 3 Tesla MR scanner. MR-guided bilaterial angioplasty of the iliac arteries was performed using a paclitaxel/MR contrast agent-coated balloon catheter. The feasibility of monitoring the delivery of Gadolinium-BOPTA to the vessel was assessed in 4 animals. In two additional animals, bilateral stenosis was surgically induced in the iliac arteries. Delivery of paclitaxel to the vessel wall was monitored using a 3 D T1-weighted gradient echo (GE) sequence for delineation of the vessel wall. Normalized signal intensity (SI) of the vessel wall was measured before and repeatedly after the intervention for 45 min. in all animals. Results: Paclitaxel/gadolinium-BOPTA-coated balloon angioplasty was successfully accomplished in all iliac arteries (n = 12). In animals with stenosis MR-angiography demonstrated successful dilatation (n = 4). The normalized SI of the vessel wall on T1-weighted GE images significantly increased after the intervention in all animals with and without stenosis for more than 45 min. (p < 0.001). Conclusion: Monitoring of Gadolinium-BOPTA into the vessel wall during MR-guided coated balloon angioplasty is feasible. This is a first step towards providing a tool for the online control of homogenous drug delivery after paclitaxel-coated balloon angioplasty. (orig.)

  11. Monitoring of gadolinium-BOPTA uptake into the vessel wall during magnetic resonance (MR)-guided angioplasty of the peripheral arteries with a paclitaxel/gadolinium-BOPTA-coated balloon. An experimental study at 3 Tesla

    Neizel, M.; Kelm, M. [University Hospital Duesseldorf (Germany). Dept. of Cardiology, Pneumology and Angiology; Ruebben, A.; Weiss, N. [Aachen Resonance, Aachen (Germany); Guenther, R.W. [University Hospital Aachen (Germany). Dept. of Radiology; Krombach, G.A. [University Hospital Giessen (Germany). Dept. of Radiology

    2014-04-15

    Purpose: The success of paclitaxel distribution within the vessel wall during paclitaxel-coated balloon angioplasty to prevent restenosis cannot be monitored under X-ray guidance. The aim of this pilot study was to demonstrate the feasibility of monitoring Gadolinium-BOPTA delivery within the vessel wall during magnetic resonance (MR)-guided paclitaxel/Gadolinium-BOPTA-coated balloon angioplasty of the peripheral arteries. Materials and methods: 6 pigs (47 ± 2 kg) were investigated. All experiments were performed using a 3 Tesla MR scanner. MR-guided bilaterial angioplasty of the iliac arteries was performed using a paclitaxel/MR contrast agent-coated balloon catheter. The feasibility of monitoring the delivery of Gadolinium-BOPTA to the vessel was assessed in 4 animals. In two additional animals, bilateral stenosis was surgically induced in the iliac arteries. Delivery of paclitaxel to the vessel wall was monitored using a 3 D T1-weighted gradient echo (GE) sequence for delineation of the vessel wall. Normalized signal intensity (SI) of the vessel wall was measured before and repeatedly after the intervention for 45 min. in all animals. Results: Paclitaxel/gadolinium-BOPTA-coated balloon angioplasty was successfully accomplished in all iliac arteries (n = 12). In animals with stenosis MR-angiography demonstrated successful dilatation (n = 4). The normalized SI of the vessel wall on T1-weighted GE images significantly increased after the intervention in all animals with and without stenosis for more than 45 min. (p < 0.001). Conclusion: Monitoring of Gadolinium-BOPTA into the vessel wall during MR-guided coated balloon angioplasty is feasible. This is a first step towards providing a tool for the online control of homogenous drug delivery after paclitaxel-coated balloon angioplasty. (orig.)

  12. Testing of a 3 tesla superconducting magnet for the AMY detector at TRISTAN

    A 3 tesla magnet was constructed and installed in an experimental hall at TRISTAN. Cooldown and excitation tests of the magnet were carried out with a dedicated cryogenic system. The coil has a 2.39 m inner diameter and is 1.54 m long with a radial thickness of 0.1 m. The rated current is 5 kA and the stored energy is 40 MJ. The refrigerator and 17-ton magnet cold mass were cooled to 4.4 K in seven days. Then the magnet was energized to the design current of 5 kA and the mechanical stress of the coil supports was measured. The stress on the supports was well below the allowed maximum. Measurements of the discharge characteristics of the magnet confirmed that the magnet was stable and reliable

  13. Rapid parametric mapping of the longitudinal relaxation time t1 using two-dimensional variable flip angle magnetic resonance imaging at 1.5 Tesla, 3 Tesla, and 7 Tesla

    Dieringer, Matthias A; Michael Deimling; Davide Santoro; Jens Wuerfel; Vince I Madai; Jan Sobesky; Florian von Knobelsdorff-Brenkenhoff; Jeanette Schulz-Menger; Thoralf Niendorf

    2014-01-01

    Introduction Visual but subjective reading of longitudinal relaxation time (T1) weighted magnetic resonance images is commonly used for the detection of brain pathologies. For this non-quantitative measure, diagnostic quality depends on hardware configuration, imaging parameters, radio frequency transmission field (B1 + ) uniformity, as well as observer experience. Parametric quantification of the tissue T1 relaxation parameter offsets the propensity for these effects, but is typically time c...

  14. No advantage of time-of-flight magnetic resonance angiography at 3 Tesla compared to 1.5 Tesla in the follow-up after endovascular treatment of cerebral aneurysms

    Buhk, Jan-Hendrik; Kallenberg, Kai; Mohr, Alexander; Dechent, Peter; Knauth, Michael

    2008-01-01

    Introduction: Long-term follow-up after coil embolization of intracranial aneurysms is mandatory to monitor coil compacting and aneurysm recurrence. Most centers perform one digital subtraction angiography (DSA) on follow-up continuing with time-of-flight magnetic resonance angiography (TOFMRA). This study explores the diagnostic value of TOFMRA at 1.5 T versus 3 T compared to DSA. Materials and methods: In 18 patients with 20 aneurysms treated with coil embolization, TOFMRA at 1.5 and 3 T we...

  15. Image distortion and artifacts caused by the use of a titanium aneurism clip in 1.5 tesla- and 3 tesla-magnetic resonance imaging. Effect on 60Cobalt stereotactic radiosurgery treatment planning

    In gamma knife stereotactic radiosurgery (GKSRS) treatment planning, 1.5 tesla (T)-magnetic resonance imaging (MRI) is normally used to identify the target lesion. Image artifacts and distortion arise in MRI if a titanium clip is surgically implanted in the brain to treat cerebral aneurysm. 3-T MRI scanners, which are increasingly being adopted, provide imaging of anatomic structures with better clinical usefulness than 1.5-T MRI machines. We investigated signal defects and image distortions both close to and more distant from the titanium clip in 1.5-T and 3-T MRI. Two kinds of phantoms were scanned using 1.5-T and 3-T MRI. Acquisitions with and without the clip were performed under the same scan parameters. No difference was observed between 1.5 T and 3 T in local decrease of signal intensity; however, image distortion was observed at 20 mm from the clip in 3 T. Over the whole region, the distortions caused by the clip were less than 0.3 mm and 1.6 mm under 1.5-T and 3-T MRI, respectively. The geometric accuracy of 1.5-T MRI was better than 3-T MRI and thus better for GKSRS treatment planning. 3-T MRI, however, appears less suitable for use in treatment planning. (author)

  16. No advantage of time-of-flight magnetic resonance angiography at 3 Tesla compared to 1.5 Tesla in the follow-up after endovascular treatment of cerebral aneurysms

    Long-term follow-up after coil embolization of intracranial aneurysms is mandatory to monitor coil compacting and aneurysm recurrence. Most centers perform one digital subtraction angiography (DSA) on follow-up continuing with time-of-flight magnetic resonance angiography (TOF-MRA). This study explores the diagnostic value of TOF-MRA at 1.5 T versus 3 T compared to DSA. In 18 patients with 20 aneurysms treated with coil embolization, TOF-MRA at 1.5 and 3 T were performed the day before follow-up DSA, the latter serving as reference. Optimized diagnostic protocols were applied (1.5T:0.78 x 0.55 x 0.8 mm, voxel size; acquisition time (TA), 6.37 min; 3T:0.56 x 0.45 x 0.65 mm, voxel size; TA, 3.12 min). Three independent neuroradiologists experienced in neuroendovascular therapy rated the occlusion rate (''complete occlusion'' vs. ''residual neck'' vs. ''residual aneurysm'') and compared the two methods subjectively. Weighted κ statistics were calculated to assess the level of interobserver agreement. Compared to DSA, TOF-MRA was more sensitive in detecting neck remnants, with a slight advantage at 3 T. Regarding artifact load, there are advantages at 1.5 T. Ratings of the occlusion rate correlated highly between all observers (r>0.85, pw∼0.8, respectively). TOF-MRA is a reliable tool for follow-up imaging of cerebral aneurysms after endovascular treatment. Our study shows no advantage of TOF-MRA at 3 T over 1.5 T, when comparable measurement protocols are applied. TOF-MRA at 1.5 T therefore provides appropriate information regarding a therapeutic decision. (orig.)

  17. Development of a 3 tesla - 10 Hz pulsed magnet-modulator system

    In order to support the experimental work done at the Los Alamos Meson Physics Facility new instrumentation and data collection systems of advanced design are developed on a regular basis. Within the instrumentation system for an experiment at LAMPF, The Photo-Excitation of the H- Ion Resonances, there exists a need for a pulsed air-core electromagnet and modulator system. The magnet must be capable of producing a field strength of 0 to 3T in a volume of 3.5 cm3. In addition it must be radiation resistant, have a uniform field, operate in a high vacuum with little or no outgassing, and the physical layout of the magnet must provide minimal azimuthal obstruction to both the ion and laser beams. The modulator must be capable of producing up to a 15KA pulse with duration of two μs at a maximum repetition rate of 10 Hz. Modulator layout must be extremely reliable so that data collection time is not lost during the experiment. This paper describes in detail the development of the system

  18. Three-Tesla magnetic resonance elastography for hepatic fibrosis: Comparison with diffusion-weighted imaging and gadoxetic acid-enhanced magnetic resonance imaging

    Park, Hee Sun; Kim, Young Jun; Yu, Mi Hye; Choe, Won Hyeok; Jung, Sung Il; Jeon, Hae Jeong

    2014-01-01

    AIM: To evaluate the feasibility of 3-Tesla magnetic resonance elastography (MRE) for hepatic fibrosis and to compare that with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced magnetic resonance (MR) imaging.

  19. A 10 Kelvin 3 Tesla Magnet for Space Flight ADR Systems

    Tuttle, Jim; Shirron, Peter; Canavan, Edgar; DiPirro, Michael; Riall, Sara; Pourrahimi, Shahin

    2003-01-01

    Many future space flight missions are expected to use adiabatic demagnetization refrigerators (ADRs) to reach detector operating temperatures well below one Kelvin. The goal is to operate each ADR with a mechanical cooler as its heat sink, thus avoiding the use of liquid cryogens. Although mechanical coolers are being developed to operate at temperatures of 6 Kelvin and below, there is a large efficiency cost associated with operating them at the bottom of their temperature range. For the multi-stage ADR system being developed at Goddard Space Flight Center, the goal is to operate with a 10 Kelvin mechanical cooler heat sink. With currently available paramagnetic materials, the highest temperature ADR stage in such a system will require a magnetic field of approximately three Tesla. Thus the goal is to develop a small, lightweight three Tesla superconducting magnet for operation at 10 Kelvin. It is important that this magnet have a low current/field ratio. Because traditional NbTi magnets do not operate safely above about six Kelvin, a magnet with a higher Tc is required. The primary focus has been on Nb3Sn magnets. Since standard Nb3Sn wire must be coated with thick insulation, wound on a magnet mandrel and then reacted, standard Nb,Sn magnets are quite heavy and require high currents Superconducting Systems developed a Nb3Sn wire which can be drawn down to small diameter, reacted, coated with thin insulation and then wound on a small diameter coil form. By using this smaller wire and operating closer to the wire s critical current, it should be possible to reduce the mass and operating current of 10 Kelvin magnets. Using this "react-then-wind" technology, Superconducting Systems has produced prototype 10 Kelvin magnets. This paper describes the development and testing of these magnets and discusses the outlook for including 10 Kelvin magnets on space-flight missions.

  20. A hyperpolarized equilibrium for magnetic resonance

    Hövener, Jan-Bernd; Schwaderlapp, Niels; Lickert, Thomas; Duckett, Simon B.; Mewis, Ryan E.; Highton, Louise A. R.; Kenny, Stephen M.; Green, Gary G. R.; Leibfritz, Dieter; Korvink, Jan G.; Hennig, Jürgen; von Elverfeldt, Dominik

    2013-12-01

    Nuclear magnetic resonance spectroscopy and imaging (MRI) play an indispensable role in science and healthcare but use only a tiny fraction of their potential. No more than ≈10 p.p.m. of all 1H nuclei are effectively detected in a 3-Tesla clinical MRI system. Thus, a vast array of new applications lays dormant, awaiting improved sensitivity. Here we demonstrate the continuous polarization of small molecules in solution to a level that cannot be achieved in a viable magnet. The magnetization does not decay and is effectively reinitialized within seconds after being measured. This effect depends on the long-lived, entangled spin-order of parahydrogen and an exchange reaction in a low magnetic field of 10-3 Tesla. We demonstrate the potential of this method by fast MRI and envision the catalysis of new applications such as cancer screening or indeed low-field MRI for routine use and remote application.

  1. Measurement of the weighted peak level for occupational exposure to gradient magnetic fields for 1.5 and 3 Tesla MRI body scanners

    The purpose of this work is to give a contribution to the construction of a comprehensive knowledge of the exposure levels to gradient magnetic fields (GMF) in terms of the weighed peak (WP), especially for 3 Tesla scanners for which there are still few works available in the literature. A new generation probe for the measurement of electromagnetic fields in the range of 1 Hz-400 kHz was used to assess the occupational exposure levels to the GMF for 1.5 and 3.0 Tesla MRI body scanners, using the method of the WP according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) approach. The probe was placed at a height of 1.1 m, close to the MRI scanners, where operators could stay during some medical procedures with particular issues. The measurements were performed for a set of typical acquisition sequences for body (liver) and head exams. The measured values of WP were in compliance with ICNIRP 2010 reference levels for occupational exposures. (authors)

  2. Measurement of the weighted peak level for occupational exposure to gradient magnetic fields for 1.5 and 3 Tesla MRI body scanners.

    Bonutti, F; Tecchio, M; Maieron, M; Trevisan, D; Negro, C; Calligaris, F

    2016-03-01

    The purpose of this work is to give a contribution to the construction of a comprehensive knowledge of the exposure levels to gradient magnetic fields (GMF) in terms of the weighed peak (WP), especially for 3 Tesla scanners for which there are still few works available in the literature. A new generation probe for the measurement of electromagnetic fields in the range of 1 Hz-400 kHz was used to assess the occupational exposure levels to the GMF for 1.5 and 3.0 Tesla MRI body scanners, using the method of the WP according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) approach. The probe was placed at a height of 1.1 m, close to the MRI scanners, where operators could stay during some medical procedures with particular issues. The measurements were performed for a set of typical acquisition sequences for body (liver) and head exams. The measured values of WP were in compliance with ICNIRP 2010 reference levels for occupational exposures. PMID:25987585

  3. Magnetic Resonance Imaging with a Dielectric Lens

    Vazquez, F; Martin, R; Rodriguez, A O

    2009-01-01

    Recently, metamaterials have been introduced to improve the signal-to-noise ratio (SNR) of magnetic resonance images with very promising results. However, the use polymers in the generation of high quality images in magnetic resonance imaging has not been fully been investigated. These investigations explored the use of a dielectric periodical array as a lens to improve the image SNR generated with single surface coils. Commercial polycarbonate glazing sheets were used together with a circular coil to generate phantom images at 3 Tesla on a clinical MR imager.

  4. Sodium-23 MRI of whole spine at 3 Tesla using a 5-channel receive-only phased-array and a whole-body transmit resonator

    Sodium magnetic resonance imaging (23Na MRI) is a unique and non-invasive imaging technique which provides important information on cellular level about the tissue of the human body. Several applications for 23Na MRI were investigated with regard to the examination of the tissue viability and functionality for example in the brain, the heart or the breast. The 23Na MRI technique can also be integrated as a potential monitoring instrument after radiotherapy or chemotherapy. The main contribution in this work was the adaptation of 23Na MRI for spine imaging, which can provide essential information on the integrity of the intervertebral disks with respect to the early detection of disk degeneration. In this work, a transmit-only receive-only dual resonator system was designed and developed to cover the whole human spine using 23Na MRI and increase the receive sensitivity. The resonator system consisted of an already presented 23Na whole-body resonator and a newly developed 5-channel receive-only phased-array. The resonator system was first validated using bench top and phantom measurements. A threefold SNR improvement at the depth of the spine (∝7 cm) over the whole-body resonator was achieved using the spine array. 23Na MR measurements of the human spine using the transmit-only receive-only resonator system were performed on a healthy volunteer within an acquisition time of 10 minutes. A density adapted 3D radial sequence was chosen with 6 mm isotropic resolution, 49 ms repetition time and a short echo time of 540 μs. Furthermore, it was possible to quantify the tissue sodium concentration in the intervertebral discs in the lumbar region (120 ms repetition time) using this setup.

  5. Sodium-23 MRI of whole spine at 3 Tesla using a 5-channel receive-only phased-array and a whole-body transmit resonator

    Malzacher, Matthias; Kalayciyan, Raffi; Konstandin, Simon; Schad, Lothar R. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Haneder, Stefan [Heidelberg Univ., Mannheim (Germany). Clinical Radiology and Nuclear Medicine; University Hospital of Cologne, Koeln (Germany). Dept. of Radiology

    2016-05-01

    Sodium magnetic resonance imaging ({sup 23}Na MRI) is a unique and non-invasive imaging technique which provides important information on cellular level about the tissue of the human body. Several applications for {sup 23}Na MRI were investigated with regard to the examination of the tissue viability and functionality for example in the brain, the heart or the breast. The {sup 23}Na MRI technique can also be integrated as a potential monitoring instrument after radiotherapy or chemotherapy. The main contribution in this work was the adaptation of {sup 23}Na MRI for spine imaging, which can provide essential information on the integrity of the intervertebral disks with respect to the early detection of disk degeneration. In this work, a transmit-only receive-only dual resonator system was designed and developed to cover the whole human spine using {sup 23}Na MRI and increase the receive sensitivity. The resonator system consisted of an already presented {sup 23}Na whole-body resonator and a newly developed 5-channel receive-only phased-array. The resonator system was first validated using bench top and phantom measurements. A threefold SNR improvement at the depth of the spine (∝7 cm) over the whole-body resonator was achieved using the spine array. {sup 23}Na MR measurements of the human spine using the transmit-only receive-only resonator system were performed on a healthy volunteer within an acquisition time of 10 minutes. A density adapted 3D radial sequence was chosen with 6 mm isotropic resolution, 49 ms repetition time and a short echo time of 540 μs. Furthermore, it was possible to quantify the tissue sodium concentration in the intervertebral discs in the lumbar region (120 ms repetition time) using this setup.

  6. Imaging Findings of Brain Death on 3-Tesla MRI

    To demonstrate the usefulness of 3-tesla (3T) magnetic resonance imaging (MRI) including T2-weighted imaging (T2WI), diffusion weighted imaging (DWI), time-of-flight (TOF) magnetic resonance angiography (MRA), T2*-weighted gradient recalled echo (GRE), and susceptibility weighted imaging (SWI) in diagnosing brain death. Magnetic resonance imaging findings for 10 patients with clinically verified brain death (group I) and seven patients with comatose or stuporous mentality who did not meet the clinical criteria of brain death (group II) were retrospectively reviewed. Tonsilar herniation and loss of intraarterial flow signal voids (LIFSV) on T2WI were highly sensitive and specific findings for the diagnosis of brain death (p < 0.001 and < 0.001, respectively). DWI, TOF-MRA, and GRE findings were statistically different between the two groups (p = 0.015, 0.029, and 0.003, respectively). However, cortical high signal intensities in T2WI and SWI findings were not statistically different between the two group (p = 0.412 and 1.0, respectively). T2-weighted imaging, DWI, and MRA using 3T MRI may be useful for diagnosing brain death. However, SWI findings are not specific due to high false positive findings.

  7. Influence on flux density of intraoral dental magnets during 1.5 and 3.0 Tesla MRI; Beeinflussung der Flussdichte intraoraler Dentalmagnete im 1,5 und 3 Tesla-MRT

    Blankenstein, F.H.; Peroz, I. [Charite, Berlin (Germany). Charite Centrum 3 - Zahn-, Mund- und Kieferheilkunde; Truong, B. [Zahnarztpraxis Berlin (Germany); Thomas, A. [Charite, Berlin (Germany). Charite Centrum 6 - Diagnostische und Interventionelle Radiologie und Nuklearmedizin; Boeckler, A. [Halle-Wittenberg Univ. (Germany). Zentrum fuer Zahn-, Mund- und Kieferheilkunde

    2011-08-15

    Purpose: When using dental duo-magnet systems, a mini-magnet remains in the jaw after removal of the prosthesis. In some cases, implant-borne magnets may be removed, whereas tooth-borne magnets are irreversibly fixed on a natural tooth root. The goal of this paper is to identify the impacts of the duration and orientation of exposure on these magnets in a 1.5 or 3 Tesla MRI. Materials and Methods: For this study, 30 SmCo and 60 NdFeB magnets were used. During the first experiment, they were exposed with free orientation for 64 minutes. During the second experiment, the magnets were fixed in position and exposed at 1.5 and 3 Tesla while aligned in a parallel or antiparallel direction. Results: While the duration of exposure in MRI is irrelevant, the orientation is not. The coercive field strength of these NdFeB and SmCo alloys is not sufficient to reliably withstand demagnetization in a 1.5 or 3 T MRI when aligned in an antiparallel direction. At 1.5 T neodymium magnets were reduced to approx. 34 % and samarium magnets to approx. 92 % of their initial values. At 3 T all magnets were reversed. Conclusion: As a precaution, the worst-case scenario, i.e. an antiparallel orientation, should be assumed when using a duo-magnet system. If an MRI can be postponed, the general dentist should remove implant-borne magnets. If there is a vital indication, irreversible damage to the magnets is acceptable in consultation with the patient since the replacement costs are irrelevant given the underlying disease. (orig.)

  8. MRI (Magnetic Resonance Imaging)

    ... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... 8 MB) Also available in Other Language versions . Magnetic Resonance Imaging (MRI) is a medical imaging procedure for making ...

  9. Incidental optochiasmatic cavernoma: Case report of an unusual finding on 3 Tesla MRI.

    Trentadue, Mirko; Pozzi Mucelli, Roberto; Piovan, Enrico; Pizzini, Francesca Benedetta

    2016-08-01

    Cavernoma is a vascular hamartoma, which represents 10-20% of all central nervous system vascular malformations. The majority (80%) of them are supratentorial, while involvement of the cranial nerves and the optic pathways is extremely rare. The main clinical presentation of optochiasmatic cavernomas consists of chiasmatic apoplexy, which is a neurosurgical emergency. Here, we report a case in which the finding was incidentally detected in a 49-year-old man. We describe the imaging characteristics of the lesion in such a rare location, highlighting the role of magnetic resonance imaging (MRI) (specifically 3 Tesla) in the management of asymptomatic patients. PMID:27145992

  10. Magnetic resonance angiography

    MRA; Angiography - magnetic resonance ... Kwong RY. Cardiovascular Magnetic Resonance Imaging. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine . ...

  11. Correlating Hemodynamic Magnetic Resonance Imaging with high-field Intracranial Vessel Wall Imaging in Stroke

    Langdon, Weston; Donahue, Manus J.; van der Kolk, Anja G.; Rane, Swati; Strother, Megan K.

    2014-01-01

    Vessel wall magnetic resonance imaging at ultra-high field (7 Tesla) can be used to visualize vascular lesions noninvasively and holds potential for improving stroke-risk assessment in patients with ischemic cerebrovascular disease. We present the first multi-modal comparison of such high-field vessel wall imaging with more conventional (i) 3 Tesla hemodynamic magnetic resonance imaging and (ii) digital subtraction angiography in a 69-year-old male with a left temporal ischemic infarct.

  12. Correlating Hemodynamic Magnetic Resonance Imaging with high-field Intracranial Vessel Wall Imaging in Stroke

    Langdon, Weston; Donahue, Manus J.; van der Kolk, Anja G.; Rane, Swati; Strother, Megan K.

    2014-01-01

    Vessel wall magnetic resonance imaging at ultra-high field (7 Tesla) can be used to visualize vascular lesions noninvasively and holds potential for improving stroke-risk assessment in patients with ischemic cerebrovascular disease. We present the first multi-modal comparison of such high-field vessel wall imaging with more conventional (i) 3 Tesla hemodynamic magnetic resonance imaging and (ii) digital subtraction angiography in a 69-year-old male with a left temporal ischemic infarct. PMID:25426229

  13. Intradiurnal fluctuations of off-resonance saturation effects in healthy human achilles tendons assessed with a 3D ultrashort echo time MRI sequence at 3 tesla

    Grosse, U.; Syha, R.; Kessler, D.E.; Bongers, M.; Seith, F.; Nikolaou, K.; Springer, F. [University Hospital Tuebingen (Germany). Dept. of Diagnostic and Interventional Radiology; Partovi, S.; Robbin, M. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Radiology; Schick, F. [University Hospital Tuebingen (Germany). Section on Experimental Radiology

    2015-11-15

    The purpose of this study was to evaluate whether gravitational interstitial fluid accumulation in healthy subjects has an impact on off-resonance saturation ratios (OSR) or the volume of the Achilles tendon after a prolonged time of reduced levels of physical activity. 7 healthy volunteers were repeatedly investigated on 3 consecutive days on a 3 T whole body MR scanner using an ultrashort echo time (UTE) imaging sequence with a Gaussian off-resonance saturation pulse at a frequency offset of 2000 Hz to calculate OSR values. For accurate volumetric quantification of the Achilles tendon, a newly developed contour detection snake algorithm was applied on high-resolution isotropic T2-weighted SPACE sequence datasets. Single-measure intraclass correlation coefficients (ICC) were calculated to estimate test-retest reliability. For OSR and tendon volume measurements on three consecutive days, excellent reproducibility could be achieved with ICC values above 0.96 and 0.97, respectively. Comparing the results of all three days, a statistically significant mean individual percentage decrease (-4.1 ± 1.5 %; p=0.001) of calculated tendon OSR values was found for the evening measurements. No statistically significant difference between tendon volumes in the morning and the evening could be detected (p=0.589). The results of this in-vivo study demonstrate a significant influence of gravitational interstitial fluid accumulation after reduced physical activity on OSR values in the Achilles tendon, but not on tendon volume. Taken together with the demonstrated excellent reproducibility, these findings are important for future studies investigating temporal changes of the Achilles tendon microstructure.

  14. Does Magnetic Resonance Brain Scanning at 3.0 Tesla Pose a Hyperthermic Challenge to Term Neonates?

    Cawley, Paul; Few, Karen; Greenwood, Richard; Malcolm, Paul; Johnson, Glyn; Lally, Pete; Thayyil, Sudhin; Clarke, Paul

    2016-08-01

    Next-generation 3-Tesla magnetic resonance (MR) scanners offer improved neonatal neuroimaging, but the greater associated radiofrequency radiation may increase the risk of hyperthermia. Safety data for neonatal 3-T MR scanning are lacking. We measured rectal temperatures continuously in 25 neonates undergoing 3-T brain MR imaging and observed no significant hyperthermic threat. PMID:27318382

  15. Magnetic Resonance Imaging (MRI)

    ... How Can I Help a Friend Who Cuts? Magnetic Resonance Imaging (MRI) KidsHealth > For Teens > Magnetic Resonance Imaging (MRI) Print A A A Text Size What's ... Exam Safety Getting Your Results What Is MRI? Magnetic resonance imaging (MRI) is a type of safe, painless testing ...

  16. Magnetic Resonance Imaging (MRI)

    ... Resonance Imaging (MRI) What is an MRI? MRI stands for Magnetic Resonance Imaging. It is an important ... MRI is often used for diagnosis or for monitoring disease. For example, if someone is having severe ...

  17. Cystic adventitial disease of the popliteal artery: features on 3T cardiovascular magnetic resonance

    Gelabert Hugh

    2008-08-01

    Full Text Available Abstract Cystic adventitial disease (CAD of the popliteal artery is a rare vascular disease of unknown etiology in which a mucin-containing cyst develops in the adventitial layer of the artery. We report the case of a 26-year-old male with CAD of the right popliteal artery diagnosed non-invasively with 3 Tesla cardiovascular magnetic resonance and confirmed on post-operative histopathology.

  18. Cystic adventitial disease of the popliteal artery: features on 3T cardiovascular magnetic resonance

    Gelabert Hugh; Finn J Paul; Lai Chi; Tomasian Anderanik; Krishnam Mayil S

    2008-01-01

    Abstract Cystic adventitial disease (CAD) of the popliteal artery is a rare vascular disease of unknown etiology in which a mucin-containing cyst develops in the adventitial layer of the artery. We report the case of a 26-year-old male with CAD of the right popliteal artery diagnosed non-invasively with 3 Tesla cardiovascular magnetic resonance and confirmed on post-operative histopathology.

  19. Technical Assessment of Artifact Production from Neuro Endovascular Coil At 3 Tesla MRI: An In Vitro Study

    Introduction: Magnetic resonance imaging (MRI) is an essential part of the diagnostic procedures in radiology. MRI 3 Tesla becomes more widespread due to high signal to noise ratio (SNR). The use of the neuro endovascular coil to overcome the neuro aneurysm can introduce the artifact in magnetic resonance imaging. Susceptibility artifacts and geometric distortions caused by magnetic field inhomogeneity- related signal loss is used to refer to an artifact in magnetic resonance images. It consists of a region of signal void with a surrounding area of an increased signal intensity that appears to be considerably larger than the actual size of the device causing the artifact. The objective of the study is to compare the size of the artifact on the MR image to the actual size of endovascular coils using a 3 Tesla magnetic resonance imaging system, in vitro study. Methods: The endovascular coils were made from detachable platinum and aneurysm models were constructed by using silicone tube. MRI 3 Tesla Philips Model Achieva with pulse sequence selections were: spin echo, fast spin echo, inversion recovery, fast gradient echo while additional parameters were echo time and turbo factor. Results: Improved visualization of perianeurysmal soft tissues is best accomplished by spin echo for fast spin echo sequences, even better suited to reduce metal artifact. Furthermore, shorter turbo factor and shorter effective TE in the latter sequences are beneficial for the same reason as sequences having shorter TE. Sequences with a shorter TE are preferred because of less time for dephasing and frequency shifting. Imaging at gradient echo series increases susceptibility artifacts. In this in vitro study, some of the major characteristics related to MRI imaging of coil packs have been defined. Discussion: Pulse sequence spin echo is the best sequence reducing the susceptibility artifact. Reducing the TE is the main factor in improving endovascular coil visualization on MRI images. The

  20. Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy in Dementias

    Hsu, Yuan-Yu; Du, An-Tao; Schuff, Norbert; Weiner, Michael W.

    2001-01-01

    This article reviews recent studies of magnetic resonance imaging and magnetic resonance spectroscopy in dementia, including Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies, idiopathic Parkinson's disease, Huntington's disease, and vascular dementia. Magnetic resonance imaging and magnetic resonance spectroscopy can detect structural alteration and biochemical abnormalities in the brain of demented subjects and may help in the differential diagnosis and early detection...

  1. Efficient isotropic magnetic resonators

    Martin, O. J. F.; Gay-Balmaz, P.

    2002-01-01

    We study experimentally and numerically a novel three-dimensional magnetic resonator structure with high isotropy. It is formed by crossed split-ring resonators and has a response independent of the illumination direction in a specific plane. The utilization of such elements to build a finite left-handed medium is discussed. (C) 2002 American Institute of Physics.

  2. The Role of 3 Tesla Diffusion-Weighted Imaging in the Differential Diagnosis of Benign versus Malignant Cervical Lymph Nodes in Patients with Head and Neck Squamous Cell Carcinoma

    Flavio Barchetti; Nicola Pranno; Guglielmo Giraldi; Alessandro Sartori; Silvia Gigli; Giovanni Barchetti; Luigi Lo Mele; Luigi Tonino Marsella

    2014-01-01

    Objective. The aim of this study was to validate the role of diffusion-weighted imaging (DWI) at 3 Tesla in the differential diagnosis between benign and malignant laterocervical lymph nodes in patients with head and neck squamous cell carcinoma (HNSCC). Materials and Methods. Before undergoing surgery, 80 patients, with biopsy proven HNSCC, underwent a magnetic resonance exam. Sensitivity (Se) and specificity (Spe) of conventional criteria and DWI in detecting laterocervical lymph node metas...

  3. Magnetic resonance imaging for detecting prostate cancer

    Magnetic resonance imaging (MRI) plays an important role in the diagnosis of prostate cancer. However, some difficulties still exist. We retrospectively studied the pathohistological accuracy of MRI, comparing with that of transrectal ultrasonography (TRUS). We used AIRIS on a 0.3 tesla MRI unit with a body coil. 50 cases (prostate cancer: 30, BPH: 20) histologically diagnosed by sextant biopsy were studied. The accuracy of clinical diagnosis in MRI and TRUS were 76% and 72%, respectively. There is no significant difference. The prostate cancer in the peripheral zone was previously reported being as a low signal intensity on the T2 weighted image. But in the present study, over 85% of the cases did not revealed so-called typical appearance. There was no advantage clarified in diagnosing prostate cancer using MRI over TRUS. There is a certain limit to MRI in diagnosing prostatic cancer. But considering its ability of three-dimensional analysis, evaluating organs locally and generally, and MRI will be more advantageous. (author)

  4. Fetal magnetic resonance imaging and ultrasound.

    Wataganara, Tuangsit; Ebrashy, Alaa; Aliyu, Labaran Dayyabu; Moreira de Sa, Renato Augusto; Pooh, Ritsuko; Kurjak, Asim; Sen, Cihat; Adra, Abdallah; Stanojevic, Milan

    2016-07-01

    Magnetic resonance imaging (MRI) has been increasingly adopted in obstetrics practice in the past three decades. MRI aids prenatal ultrasound and improves diagnostic accuracy for selected maternal and fetal conditions. However, it should be considered only when high-quality ultrasound cannot provide certain information that affects the counseling, prenatal intervention, pregnancy course, and delivery plan. Major indications of fetal MRI include, but are not restricted to, morbidly adherent placenta, selected cases of fetal brain anomalies, thoracic lesions (especially in severe congenital diaphragmatic hernia), and soft tissue tumors at head and neck regions of the fetus. For fetal anatomy assessment, a 1.5-Tesla machine with a fast T2-weighted single-shot technique is recommended for image requisition of common fetal abnormalities. Individual judgment needs to be applied when considering usage of a 3-Tesla machine. Gadolinium MRI contrast is not recommended during pregnancy. MRI should be avoided in the first half of pregnancy due to small fetal structures and motion artifacts. Assessment of fetal cerebral cortex can be achieved with MRI in the third trimester. MRI is a viable research tool for noninvasive interrogation of the fetus and the placenta. PMID:27092644

  5. Advances in magnetic resonance 10

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 10, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters that examine superoperators in magnetic resonance; ultrasonically modulated paramagnetic resonance; and the utility of electron paramagnetic resonance (EPR) and electron-nuclear double-resonance (ENDOR) techniques for studying low-frequency modes of atomic fluctuations and their significance for understanding the mechanism of structural phase transitions in solids.

  6. Functional Magnetic Resonance Imaging

    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…

  7. Resonant magnetic vortices

    By using the complex angular momentum method, we provide a semiclassical analysis of electron scattering by a magnetic vortex of Aharonov-Bohm type. Regge poles of the S matrix are associated with surface waves orbiting around the vortex and supported by a magnetic field discontinuity. Rapid variations of sharp characteristic shapes can be observed on scattering cross sections. They correspond to quasibound states which are Breit-Wigner-type resonances associated with surface waves and which can be considered as quantum analogues of acoustic whispering-gallery modes. Such a resonant magnetic vortex could provide a different kind of artificial atom while the semiclassical approach developed here could be profitably extended in various areas of the physics of vortices

  8. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... during MRI, but this is rarely a problem. Tooth fillings and braces usually are not affected by ... Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic Resonance Imaging ( ...

  9. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) ... conditions such as: brain tumors stroke infections developmental anomalies hydrocephalus — dilatation of fluid spaces within the brain ( ...

  10. Magnetic Resonance Imaging (MRI) Safety

    ... 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 very ...

  11. Magnetic resonance of phase transitions

    Owens, Frank J; Farach, Horacio A

    1979-01-01

    Magnetic Resonance of Phase Transitions shows how the effects of phase transitions are manifested in the magnetic resonance data. The book discusses the basic concepts of structural phase and magnetic resonance; various types of magnetic resonances and their underlying principles; and the radiofrequency methods of nuclear magnetic resonance. The text also describes quadrupole methods; the microwave technique of electron spin resonance; and the Mössbauer effect. Phase transitions in various systems such as fluids, liquid crystals, and crystals, including paramagnets and ferroelectrics, are also

  12. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  13. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  14. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head ... limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is ...

  15. Neuromelanin imaging of the substantia nigra and locus ceruleus among patients with Parkinson's disease using 3Tesla MRI

    Parkinson's disease (PD) is a progressive neurodegenerative disorder in which loss of dopaminergic neurons from the pars compacta of substantia nigra (SNc) and locus ceruleus (LC) in the major pathologic substrate. To investigate the relationships between the loss of SNc and LC neurons, and the stage of illness, we compared the signal intensity of SNc and LC between PD patients and normal controls by using a neuromelanin-sensitive magnetic resonance imaging (MRI) at 3 Tesla. We examined 41 PD patients in early stage, 10 in progressive stage, and 22 healthy controls. In PD, we observed a significant loss of neuromelanin in LC (p<0.0001) and lateral area of SNc (p=0.0011) while no significant difference between neuromelanin imaging and severity of PD was observed. The present study suggests that neuromelanin imaging using 3T MRI is a useful tool for early diagnosis of Parkinson's disease. (author)

  16. Parallel Magnetic Resonance Imaging

    Uecker, Martin

    2015-01-01

    The main disadvantage of Magnetic Resonance Imaging (MRI) are its long scan times and, in consequence, its sensitivity to motion. Exploiting the complementary information from multiple receive coils, parallel imaging is able to recover images from under-sampled k-space data and to accelerate the measurement. Because parallel magnetic resonance imaging can be used to accelerate basically any imaging sequence it has many important applications. Parallel imaging brought a fundamental shift in image reconstruction: Image reconstruction changed from a simple direct Fourier transform to the solution of an ill-conditioned inverse problem. This work gives an overview of image reconstruction from the perspective of inverse problems. After introducing basic concepts such as regularization, discretization, and iterative reconstruction, advanced topics are discussed including algorithms for auto-calibration, the connection to approximation theory, and the combination with compressed sensing.

  17. Cavity- and waveguide-resonators in electron paramagnetic resonance, nuclear magnetic resonance, and magnetic resonance imaging.

    Webb, Andrew

    2014-11-01

    Cavity resonators are widely used in electron paramagnetic resonance, very high field magnetic resonance microimaging and also in high field human imaging. The basic principles and designs of different forms of cavity resonators including rectangular, cylindrical, re-entrant, cavity magnetrons, toroidal cavities and dielectric resonators are reviewed. Applications in EPR and MRI are summarized, and finally the topic of traveling wave MRI using the magnet bore as a waveguide is discussed. PMID:25456314

  18. Double-bundle depiction of the anterior cruciate ligament at 3 Tesla

    Adriaensen, M.E.A.P.M. [Atrium Medical Center Parkstad, Department of Radiology, Heerlen (Netherlands); Hogan, B. [Sports Surgery Clinic, Department of Radiology, Dublin (Ireland); Al-Bulushi, H.I.J. [Armed Forces Hospital, Department of Radiology, Muscat (Oman); Kavanagh, E.C. [Mater Misericordiae Hospital, Department of Radiology, Dublin (Ireland)

    2012-07-15

    Magnetic resonance imaging on 3 Tesla (3T MRI) with arthroscopic correlation has proven to adequately identify the anteromedial bundle (AMB) and posterolateral bundle (PLB) in cadaver knees. The purpose of this study was to describe the depiction of ACL bundle anatomy on 3T MRI in daily practice. In a retrospective cohort study, we included 50 consecutive patients who underwent standard 3T MRI of the knee and had an intact ACL. Two musculoskeletal radiologists independently reviewed all scans for depiction of ACL bundle anatomy using standardized forms. Descriptive statistics were used. Twenty-three right knees (46%) and 27 left knees (54%) were included in the study. Mean age of the patients was 35 years (range 12 to 68 years); 37 patients were male (74%). ACL bundle anatomy was best depicted in the axial plane in 44 knees (88%) and in the coronal plane in six knees (12%). Two bundles were seen in 47 knees (94%). The AMB was completely seen in 45 knees (90%). The PLB was completely seen in 40 knees (80%). Both bundles were completely seen in 37 knees (76%). The double-bundle anatomy of the ACL is visualized in 94% of patients on 3T MRI. Because of potentially associated clinical benefits, we advocate to report separately on the anteromedial bundle and posterolateral bundle in case of anterior cruciate ligament injury of the knee. (orig.)

  19. Double-bundle depiction of the anterior cruciate ligament at 3 Tesla

    Magnetic resonance imaging on 3 Tesla (3T MRI) with arthroscopic correlation has proven to adequately identify the anteromedial bundle (AMB) and posterolateral bundle (PLB) in cadaver knees. The purpose of this study was to describe the depiction of ACL bundle anatomy on 3T MRI in daily practice. In a retrospective cohort study, we included 50 consecutive patients who underwent standard 3T MRI of the knee and had an intact ACL. Two musculoskeletal radiologists independently reviewed all scans for depiction of ACL bundle anatomy using standardized forms. Descriptive statistics were used. Twenty-three right knees (46%) and 27 left knees (54%) were included in the study. Mean age of the patients was 35 years (range 12 to 68 years); 37 patients were male (74%). ACL bundle anatomy was best depicted in the axial plane in 44 knees (88%) and in the coronal plane in six knees (12%). Two bundles were seen in 47 knees (94%). The AMB was completely seen in 45 knees (90%). The PLB was completely seen in 40 knees (80%). Both bundles were completely seen in 37 knees (76%). The double-bundle anatomy of the ACL is visualized in 94% of patients on 3T MRI. Because of potentially associated clinical benefits, we advocate to report separately on the anteromedial bundle and posterolateral bundle in case of anterior cruciate ligament injury of the knee. (orig.)

  20. Magnetic Resonance Facility (Fact Sheet)

    2012-03-01

    This fact sheet provides information about Magnetic Resonance Facility capabilities and applications at NREL's National Bioenergy Center. Liquid and solid-state analysis capability for a variety of biomass, photovoltaic, and materials characterization applications across NREL. NREL scientists analyze solid and liquid samples on three nuclear magnetic resonance (NMR) spectrometers as well as an electron paramagnetic resonance (EPR) spectrometer.

  1. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  2. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful magnetic ... that are clearer and more detailed than other imaging methods. This exam does not use ionizing radiation ...

  3. Dental magnetic resonance imaging

    Growing distribution and utilization of digital volume tomography (DVT) extend the spectrum of clinical dental imaging. Additional diagnostic value, however, comes along with an increasing amount of radiation. In contrast, magnetic resonance imaging is a radiation free imaging technique. Furthermore, it offers a high soft tissue contrast. Morphological and numerical dental anomalies, differentiation of periapical lesions and exclusion of complications of dental diseases are field of applications for dental MRI. In addition, detection of caries and periodontal lesions and injury of inferior alveolar nerve are promising application areas in the future.

  4. Cranial magnetic resonance imaging

    Cranial Magnetic Resonance Imaging is comprehensive, well structured, and well written. The material is current and well referenced. The illustrations are good and complement the text well. The overall quality of publication is above average. The greatest attribute of the book is its readability. The author demonstrates ample skill in making complex subjects, such as MR physics and imaging of cerebral hemorrhage, easy to understand. The book closes with a detailed atlas on the anatomic appearance of the brain on MR images in the axial, coronal, and sagittal planes

  5. Magnetic resonance imaging equipments

    Magnetic resonance imaging (MRI) is a new examination technique used in diagnostic medicine. Its use has increased notably during the last few years in Finland, too. The biological effects of electromagnetic fields used in MRI are quite different from the effects of x-rays. This report introduces the physics and the techniques of MRI; the biological effects of magnetic fields and the hazards associated with the use of MRI systems are briefly discussed. The major national and international recommendations are summarized, too. Furthermore, a description is given how safety aspects are considered in Finnish MRI units. Finally, recommendations are given to restrict the exposure caused by MRI and to ensure the safe use of MRI. Diagnostic applications and clinical or economic aspects fall outside the scope of this report. (orig.)

  6. Advances in magnetic resonance 11

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 11, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters and begins with a discussion of the principles and applications of dynamic nuclear polarization, with emphasis on molecular motions and collisions, intermolecular couplings, and chemical interactions. Subsequent chapters focus on the assessment of a proposed broadband decoupling method and studies of time-domain (or Fourier transform) multiple-quantum nuclear magnetic resonance.

  7. Insula-specific 1H magnetic resonance spectroscopy reactions in heavy smokers under acute nicotine withdrawal and after oral nicotine substitution

    Gutzeit, Andreas; Froehlich, Johannes M; Hergan, Klaus; Graf, Nicole; Binkert, Christoph A; Meier, Dieter; Brügger, Mike; Reischauer, Carolin; Sutter, Reto; Herdener, Marcus; Schubert, Tillmann; Kos, Sebastian; Grosshans, Martin; Straka, Matus; Mutschler, Jochen

    2013-01-01

    The aim of this study was to clarify whether addiction-specific neurometabolic reaction patterns occur in the insular cortex during acute nicotine withdrawal in tobacco smokers in comparison to nonsmokers. Fourteen male smokers and 10 male nonsmokers were included. Neurometabolites of the right and the left insular cortices were quantified by magnetic resonance spectroscopy (MRS) on a 3-Tesla scanner. Three separate MRS measurements were performed in each subject: among the smokers, the first...

  8. Role of 3T multiparametric magnetic resonance imaging without endorectal coil in the detection of local recurrent prostate cancer after radical prostatectomy: the radiation oncology point of view

    Couñago, Felipe; Cerro, Elia del; Díaz, Ana Aurora; Marcos, Francisco José; Cerezo, Laura; Maldonado, Antonio; Thuissard Vasallo, Israel John; Rodríguez Martín, José Luis

    2015-01-01

    The aims of this study were to evaluate the role of 3 tesla multiparametric magnetic resonance imaging (3TmMRI) without endorectal coil in the detection of radiographic local recurrences (rLRs) in a contemporary cohort of patients with prostate cancer who presented with biochemical recurrence after radical prostatectomy (RP) with low prostate-specific antigen (PSA) levels, and to identify clinical parameters associated with the 3TmMRI findings.

  9. Advances in magnetic resonance 6

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 6 focuses on the theoretical and practical aspects of applying magnetic resonance methods to various problems in physical chemistry, emphasizing the different aspects of the exegesis of these problems. This book discusses the gas phase magnetic resonance of electronically excited molecules; techniques for observing excited electronic states; NMR studies in liquids at high pressure; and effect of pressure on self-diffusion in liquids. The nuclear magnetic resonance investigations of organic free radicals; measurement of proton coupling constants by NMR; an

  10. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... or cause problems during an MRI exam. Nephrogenic systemic fibrosis is currently a recognized, but rare, complication ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... the same effect. A very irregular heartbeat may affect the quality of images obtained using techniques that ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  12. Ventricular Assist Device implant (AB 5000) prototype cannula: In vitro assessment of MRI issues at 3-Tesla

    Valencerina Samuel; Shellock Frank G

    2008-01-01

    Abstract Purpose To evaluate MRI issues at 3-Tesla for a ventricular assist device (VAD). Methods The AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached (Abiomed, Inc., Danvers, MA) was evaluated for magnetic field interactions, heating, and artifacts at 3-Tesla. MRI-related heating was assessed with the device in a gelled-saline-filled, head/torso phantom using a transmit/received RF body coil while performing MRI at a whole body averaged ...

  13. Magnetic resonance in neuroborreliosis

    Magnetic resonance (MR) is commonly used in diagnosing infections of the central nervous system. The aim of the study is to evaluate central nervous system changes in neuroborreliosis patients. MR examinations were performed in 44 patients with clinical symptoms, epidemiology and laboratory tests results of neuroborreliosis. Abnormalities were detected in 22 patients. Most of them presented cortico-subcortical atrophy (86%). In 9 cases foci of increased signal in T2-weighted and FLAIR images were observed in white matter. They were single or multiple, located subcorticaly and paraventriculary. In 2 subjects areas of increased signal were found in the brain stem. Central nervous system abnormalities detected with MR are not specific for Lyme disease. They can suggest demyelinating lesions and/or gliosis observed in many nervous system disorders (SM, ADEM, lacunar infarcts). (author)

  14. MRI at 3 Tesla detects no evidence for ischemic brain damage in intensively treated patients with homozygous familial hypercholesterolemia

    Schmitz, Stephan A.; O' Regan, Declan P.; Fitzpatrick, Julie; Hajnal, Joseph V. [Hammersmith Hospital Campus, Imaging Sciences Department, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, London (United Kingdom); Neuwirth, Clare; Potter, Elizabeth; Tosi, Isabella; Naoumova, Rossi P. [MRC Clinical Sciences Centre, Clinical Research Facility, London (United Kingdom); Hammersmith Hospital, Lipid Clinic, London (United Kingdom)

    2007-11-15

    Homozygous familial hypercholesterolemia (FH) is considered a model disease for excessive plasma cholesterol levels. Patients with untreated homozygous FH have a markedly increased risk for premature atherosclerosis. The frequency and extent of ischemic brain damage detectable by high-field magnetic resonance imaging (MRI) after long-term intensive treatment are unknown. In a case control study, five patients with homozygous FH (one male and four females; mean age: 23.6 {+-} 9.2, range: 12-36 years; mean pre-treatment serum total cholesterol level: 26.9 {+-} 3.24 mmol/L; all patients with documented atherosclerotic plaques in the carotid arteries) and five age- and sex-matched healthy controls were studied. All patients had been on maximal lipid-lowering medication since early childhood, and four of them were also on treatment with low-density lipoprotein (LDL) apheresis at bi-weekly intervals. Brain MRI was performed at 3 Tesla field strength with fluid-attenuated T2-weighted inversion recovery and T1-weighted spin-echo MR pulse sequences and subsequently evaluated by two independent readers. The maximal lipid-lowering treatment reduced the total serum cholesterol by more than 50% in the patients, but their serum concentrations were still 3.6-fold higher than those found in the controls (11.9 {+-} 4.2 vs. 4.5 {+-} 0.5 mmol/L; p < 0.0047). No brain abnormality was observed in any of the patients with homozygous FH. Homozygous FH patients on intensive cholesterol-lowering therapy have no evidence of ischemic brain damage at 3 Tesla MRI despite the remaining high cholesterol levels. (orig.)

  15. MRI at 3 Tesla detects no evidence for ischemic brain damage in intensively treated patients with homozygous familial hypercholesterolemia

    Homozygous familial hypercholesterolemia (FH) is considered a model disease for excessive plasma cholesterol levels. Patients with untreated homozygous FH have a markedly increased risk for premature atherosclerosis. The frequency and extent of ischemic brain damage detectable by high-field magnetic resonance imaging (MRI) after long-term intensive treatment are unknown. In a case control study, five patients with homozygous FH (one male and four females; mean age: 23.6 ± 9.2, range: 12-36 years; mean pre-treatment serum total cholesterol level: 26.9 ± 3.24 mmol/L; all patients with documented atherosclerotic plaques in the carotid arteries) and five age- and sex-matched healthy controls were studied. All patients had been on maximal lipid-lowering medication since early childhood, and four of them were also on treatment with low-density lipoprotein (LDL) apheresis at bi-weekly intervals. Brain MRI was performed at 3 Tesla field strength with fluid-attenuated T2-weighted inversion recovery and T1-weighted spin-echo MR pulse sequences and subsequently evaluated by two independent readers. The maximal lipid-lowering treatment reduced the total serum cholesterol by more than 50% in the patients, but their serum concentrations were still 3.6-fold higher than those found in the controls (11.9 ± 4.2 vs. 4.5 ± 0.5 mmol/L; p < 0.0047). No brain abnormality was observed in any of the patients with homozygous FH. Homozygous FH patients on intensive cholesterol-lowering therapy have no evidence of ischemic brain damage at 3 Tesla MRI despite the remaining high cholesterol levels. (orig.)

  16. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a ...

  17. Advances in magnetic resonance 12

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 12, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains six chapters and begins with a discussion of diffusion and self-diffusion measurements by nuclear magnetic resonance. This is followed by separate chapters on spin-lattice relaxation time in hydrogen isotope mixtures; the principles of optical detection of nuclear spin alignment and nuclear quadropole resonance; and the spin-1 behavior, including the relaxation of the quasi-invariants of the motion of a system of pairs of dipolar coupled spin-1/2 nu

  18. Magnetic resonance imaging methodology

    Magnetic resonance (MR) methods are non-invasive techniques to provide detailed, multi-parametric information on human anatomy, function and metabolism. Sensitivity, specificity, spatial and temporal resolution may, however, vary depending on hardware (e.g., field strength, gradient strength and speed) and software (optimised measurement protocols and parameters for the various techniques). Furthermore, multi-modality imaging may enhance specificity to better characterise complex disease patterns. Positron emission tomography (PET) is an interesting, largely complementary modality, which might be combined with MR. Despite obvious advantages, combining these rather different physical methods may also pose challenging problems. At this early stage, it seems that PET quality may be preserved in the magnetic field and, if an adequate detector material is used for the PET, MR sensitivity should not be significantly degraded. Again, this may vary for the different MR techniques, whereby functional and metabolic MR is more susceptible than standard anatomical imaging. Here we provide a short introduction to MR basics and MR techniques, also discussing advantages, artefacts and problems when MR hardware and PET detectors are combined. In addition to references for more detailed descriptions of MR fundamentals and applications, we provide an early outlook on this novel and exciting multi-modality approach to PET/MR. (orig.)

  19. Detailed imaging of the normal anatomy and pathologic conditions of the cavernous region at 3 Tesla using a contrast-enhanced MR angiography

    The purpose of this study was to evaluate the potential of a high-resolution contrast-enhanced magnetic resonance angiography (CE-MRA) at 3 Tesla for the delineation of the cavernous sinus (CS) anatomy both under normal and under pathological conditions. Fifteen patients without pathologies in the CS and ten patients with pituitary adenomas were included. The CE-MRA was performed on a 3-Tesla scanner and analyzed collaboratively by two readers. The cranial nerves (CNs) within the CS, namely CNIII, CNIV, CNV1, CNV2, and CNVI, were identified in both patient groups. In the adenoma patients it was also assessed whether and to which extend the adenoma invaded the CS and the spatial relationship between tumor and CNs was determined. In the patients with normal CS anatomy, CNIII could be identified in 100%, CNIV in 86.7%, and CNV1, CNV2, as well as CNVI in 100% of analyzed sides. Pituitary adenomas invaded the CS unilaterally (right side) in four patients, and bilaterally in six patients. In patients with adenomas, the CN could be identified and differentiated from the tumor in the following percentages: CNIII in 100%, CNIV in 70%, both CNV1 and CNV2 in 90%, and CNVI in 100%. In all these cases, the tumor-nerve spatial relationship could be visualized. 3-Tesla CE-MRA allows detailed imaging of the complex anatomy of the CS and its structures. In adenoma patients, it clearly visualizes the spatial relationship between tumor and CNs, and thus might be helpful to optimize presurgical planning. (orig.)

  20. Detailed imaging of the normal anatomy and pathologic conditions of the cavernous region at 3 Tesla using a contrast-enhanced MR angiography

    Linn, Jennifer; Peters, Friederike; Lummel, Nina; Brueckmann, Hartmut; Yousry, Indra [University Hospital Munich, Department of Neuroradiology, Munich (Germany); Schankin, Christoph [University Hospital Munich, Department of Neurology, Munich (Germany); Rachinger, Walter [University Hospital Munich, Department of Neurosurgery, Munich (Germany)

    2011-12-15

    The purpose of this study was to evaluate the potential of a high-resolution contrast-enhanced magnetic resonance angiography (CE-MRA) at 3 Tesla for the delineation of the cavernous sinus (CS) anatomy both under normal and under pathological conditions. Fifteen patients without pathologies in the CS and ten patients with pituitary adenomas were included. The CE-MRA was performed on a 3-Tesla scanner and analyzed collaboratively by two readers. The cranial nerves (CNs) within the CS, namely CNIII, CNIV, CNV1, CNV2, and CNVI, were identified in both patient groups. In the adenoma patients it was also assessed whether and to which extend the adenoma invaded the CS and the spatial relationship between tumor and CNs was determined. In the patients with normal CS anatomy, CNIII could be identified in 100%, CNIV in 86.7%, and CNV1, CNV2, as well as CNVI in 100% of analyzed sides. Pituitary adenomas invaded the CS unilaterally (right side) in four patients, and bilaterally in six patients. In patients with adenomas, the CN could be identified and differentiated from the tumor in the following percentages: CNIII in 100%, CNIV in 70%, both CNV1 and CNV2 in 90%, and CNVI in 100%. In all these cases, the tumor-nerve spatial relationship could be visualized. 3-Tesla CE-MRA allows detailed imaging of the complex anatomy of the CS and its structures. In adenoma patients, it clearly visualizes the spatial relationship between tumor and CNs, and thus might be helpful to optimize presurgical planning. (orig.)

  1. Assessment of MRI issues at 3-Tesla for metallic surgical implants: findings applied to 61 additional skin closure staples and vessel ligation clips

    Gill Amreeta; Shellock Frank G

    2012-01-01

    Abstract Purpose Metallic skin closure staples and vessel ligation clips should be tested at 3-Tesla to characterize MRI issues in order to ensure patient safety. Therefore, metallic surgical implants were assessed at 3-Tesla for magnetic field interactions, MRI-related heating, and artifacts. Methods A skin closure staple (Visistat Skin Stapler, staple, Polytetrafluoroethylene, PTFE, coated 316L/316LVM stainless steel; Teleflex Medical, Durham, NC) and a vessel ligation clip (Hemoclip Tradit...

  2. Magnetic Resonance angiography. Pt 1

    The objective of this paper is to describe the basic physical principles important in magnetic resonance angiography (MRA). The data used were obtained from recent articles on MRA and direct experience working with prototype MRA sequence. The information is presented in a manner suitable for those unfamiliar with the principles of MRA and magnetic resonance imaging (MRI). Magnetic resonance angiography is an important method that can be used to obtain angiograms without the injection of intravascular contrast medium. It is already proving to be of clinical use in the assessment of vascular disease. 11 refs., 5 figs

  3. Advances in magnetic resonance 9

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 9 describes the magnetic resonance in split constants and dipolar relaxation. This book discusses the temperature-dependent splitting constants in the ESR spectra of organic free radicals; temperature-dependent splittings in ion pairs; and magnetic resonance induced by electrons. The electron impact excitation of atoms and molecules; intramolecular dipolar relaxation in multi-spin systems; and dipolar cross-correlation problem are also elaborated. This text likewise covers the NMR studies of molecules oriented in thermotropic liquid crystals and diffusion

  4. Advances in magnetic resonance 1

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 1, discusses developments in various areas of magnetic resonance. The subject matter ranges from original theoretical contributions through syntheses of points of view toward series of phenomena to critical and painstaking tabulations of experimental data. The book contains six chapters and begins with a discussion of the theory of relaxation processes. This is followed by separate chapters on the development of magnetic resonance techniques for studying rate processes in chemistry and the application of these techniques to various problems; the geometri

  5. Functional magnetic resonance imaging.

    Buchbinder, Bradley R

    2016-01-01

    Functional magnetic resonance imaging (fMRI) maps the spatiotemporal distribution of neural activity in the brain under varying cognitive conditions. Since its inception in 1991, blood oxygen level-dependent (BOLD) fMRI has rapidly become a vital methodology in basic and applied neuroscience research. In the clinical realm, it has become an established tool for presurgical functional brain mapping. This chapter has three principal aims. First, we review key physiologic, biophysical, and methodologic principles that underlie BOLD fMRI, regardless of its particular area of application. These principles inform a nuanced interpretation of the BOLD fMRI signal, along with its neurophysiologic significance and pitfalls. Second, we illustrate the clinical application of task-based fMRI to presurgical motor, language, and memory mapping in patients with lesions near eloquent brain areas. Integration of BOLD fMRI and diffusion tensor white-matter tractography provides a road map for presurgical planning and intraoperative navigation that helps to maximize the extent of lesion resection while minimizing the risk of postoperative neurologic deficits. Finally, we highlight several basic principles of resting-state fMRI and its emerging translational clinical applications. Resting-state fMRI represents an important paradigm shift, focusing attention on functional connectivity within intrinsic cognitive networks. PMID:27432660

  6. Improved in vivo detection of cortical lesions in multiple sclerosis using double inversion recovery MR imaging at 3 Tesla

    To investigate the impact of a higher magnetic field strength of 3 Tesla (T) on the detection rate of cortical lesions in multiple sclerosis (MS) patients, in particular using a dedicated double inversion recovery (DIR) pulse sequence. Thirty-four patients with clinically isolated syndromes or definite MS were included. All patients underwent magnetic resonance imaging (MRI) at 1.5 T and 3 T, including T2-weighted turbo spin echo (TSE), fluid-attenuated inversion recovery (FLAIR) and DIR sequences. All images were analysed for focal lesions categorised according to their anatomical location. The total number of detected lesions was higher at 3 T across all pulse sequences. We observed significantly higher numbers of lesions involving the cortex at 3 T using a DIR sequence. DIR at 3 T showed 192% more pure intracortical (p < 0.001) and 30% more mixed grey matter-white matter lesions (p = 0.008). No significant increase in cortical lesions could be detected on the FLAIR and T2-weighted images. Using the T2-weighted and FLAIR sequences, significantly more lesions could be detected at 3 T in the infratentorial, periventricular and juxtacortical white matter. DIR brain MR imaging at 3 T substantially improves the sensitivity of the detection of cortical lesions compared with the standard magnetic field strength of 1.5 T. (orig.)

  7. Magnetic resonance energy and topological resonance energy.

    Aihara, Jun-Ichi

    2016-04-28

    Ring-current diamagnetism of a polycyclic π-system is closely associated with thermodynamic stability due to the individual circuits. Magnetic resonance energy (MRE), derived from the ring-current diamagnetic susceptibility, was explored in conjunction with graph-theoretically defined topological resonance energy (TRE). For many aromatic molecules, MRE is highly correlative with TRE with a correlation coefficient of 0.996. For all π-systems studied, MRE has the same sign as TRE. The only trouble with MRE may be that some antiaromatic and non-alternant species exhibit unusually large MRE-to-TRE ratios. This kind of difficulty can in principle be overcome by prior geometry-optimisation or by changing spin multiplicity. Apart from the semi-empirical resonance-theory resonance energy, MRE is considered as the first aromatic stabilisation energy (ASE) defined without referring to any hypothetical polyene reference. PMID:26878709

  8. A systematic review of the utility of 1.5 versus 3 Tesla magnetic resonance brain imaging in clinical practice and research

    Wardlaw, Joanna M. [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of Edinburgh, Division of Clinical Neurosciences, Edinburgh (United Kingdom); Western General Hospital, SINAPSE Collaboration, Brain Research Imaging Centre, Division of Clinical Neurosciences, Edinburgh (United Kingdom); Brindle, Will; Casado, Ana M.; Thomas, Brenda; Morris, Zoe [University of Edinburgh, Division of Clinical Neurosciences, Edinburgh (United Kingdom); Shuler, Kirsten; Henderson, Moira; Munoz Maniega, Susana; Lymer, Katherine; Pernet, Cyril; Tao, Yuehui [Terry; Parikh, Jehill; Royle, Natalie A.; Bastin, Mark E.; Farrall, Andrew; Valdes Hernandez, Maria C. [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of Edinburgh, Division of Clinical Neurosciences, Edinburgh (United Kingdom); Macfarlane, Jennifer [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of Dundee, Dundee (United Kingdom); Nailon, William [University of Edinburgh, Edinburgh Cancer Centre, Edinburgh (United Kingdom); Ahearn, Trevor [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of Aberdeen, Institute of Medical Sciences, Aberdeen (United Kingdom); Mumuni, Abdul Nashirudeen [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of Glasgow, Department of Clinical Physics, Glasgow (United Kingdom); Mugruza, Carlos [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of Dundee, School of Psychology, Dundee (United Kingdom); McLean, John [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of Glasgow, Institute of Neurological Sciences, Glasgow (United Kingdom); Chakirova, Goultchira [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of Edinburgh, Division of Psychiatry, Edinburgh (United Kingdom); Simpson, Johanna [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of Stirling, Department of Psychology, Stirling (United Kingdom); Stanfield, Andrew C. [University of Edinburgh, Division of Psychiatry, Edinburgh (United Kingdom); Johnston, Harriet [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of St Andrews, Department of Psychology, St Andrews (United Kingdom); De Wilde, Janet [Scottish Imaging Network, A Platform for Scientific Excellence (SINAPSE) Collaboration, Edinburgh (United Kingdom); University of Edinburgh, Division of Clinical Neurosciences, Edinburgh (United Kingdom); The Higher Education Academy, York (United Kingdom); Weir, Nick [Royal Infirmary of Edinburgh, Department of Medical Physics, Edinburgh (United Kingdom); Collaboration: SINAPSE Collaborative Group

    2012-11-15

    MRI at 3 T is said to be more accurate than 1.5 T MR, but costs and other practical differences mean that it is unclear which to use. We systematically reviewed studies comparing diagnostic accuracy at 3 T with 1.5 T. We searched MEDLINE, EMBASE and other sources from 1 January 2000 to 22 October 2010 for studies comparing diagnostic accuracy at 1.5 and 3 T in human neuroimaging. We extracted data on methodology, quality criteria, technical factors, subjects, signal-to-noise, diagnostic accuracy and errors according to QUADAS and STARD criteria. Amongst 150 studies (4,500 subjects), most were tiny, compared old 1.5 T with new 3 T technology, and only 22 (15 %) described diagnostic accuracy. The 3 T images were often described as ''crisper'', but we found little evidence of improved diagnosis. Improvements were limited to research applications [functional MRI (fMRI), spectroscopy, automated lesion detection]. Theoretical doubling of the signal-to-noise ratio was not confirmed, mostly being 25 %. Artefacts were worse and acquisitions took slightly longer at 3 T. Objective evidence to guide MRI purchasing decisions and routine diagnostic use is lacking. Rigorous evaluation accuracy and practicalities of diagnostic imaging technologies should be the routine, as for pharmacological interventions, to improve effectiveness of healthcare. (orig.)

  9. Preoperative 3-Tesla Multiparametric Endorectal Magnetic Resonance Imaging Findings and the Odds of Upgrading and Upstaging at Radical Prostatectomy in Men With Clinically Localized Prostate Cancer

    Purpose: To investigate whether 3-T esla (3T) multiparametric endorectal MRI (erMRI) can add information to established predictors regarding occult extraprostatic or high-grade prostate cancer (PC) in men with clinically localized PC. Methods and Materials: At a single academic medical center, this retrospective study's cohort included 118 men with clinically localized PC who underwent 3T multiparametric erMRI followed by radical prostatectomy, from 2008 to 2011. Multivariable logistic regression analyses in all men and in 100 with favorable-risk PC addressed whether erMRI evidence of T3 disease was associated with prostatectomy T3 or Gleason score (GS) 8-10 (in patients with biopsy GS ≤7) PC, adjusting for age, prostate-specific antigen level, clinical T category, biopsy GS, and percent positive biopsies. Results: The accuracy of erMRI prediction of extracapsular extension and seminal vesicle invasion was 75% and 95%, respectively. For all men, erMRI evidence of a T3 lesion versus T2 was associated with an increased odds of having pT3 disease (adjusted odds ratio [AOR] 4.81, 95% confidence interval [CI] 1.36-16.98, P=.015) and pGS 8-10 (AOR 5.56, 95% CI 1.10-28.18, P=.038). In the favorable-risk population, these results were AOR 4.14 (95% CI 1.03-16.56), P=.045 and AOR 7.71 (95% CI 1.36-43.62), P=.021, respectively. Conclusions: Three-Tesla multiparametric erMRI in men with favorable-risk PC provides information beyond that contained in known preoperative predictors about the presence of occult extraprostatic and/or high-grade PC. If validated in additional studies, this information can be used to counsel men planning to undergo radical prostatectomy or radiation therapy about the possible need for adjuvant radiation therapy or the utility of adding hormone therapy, respectively.

  10. Preoperative 3-Tesla Multiparametric Endorectal Magnetic Resonance Imaging Findings and the Odds of Upgrading and Upstaging at Radical Prostatectomy in Men With Clinically Localized Prostate Cancer

    Hegde, John V. [Harvard Medical School, Boston, Massachusetts (United States); Department of Radiology, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Chen, Ming-Hui [Department of Statistics, University of Connecticut, Storrs, Connecticut (United States); Mulkern, Robert V. [Department of Radiology, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Department of Radiology, Children' s Hospital Boston, Boston, Massachusetts (United States); Fennessy, Fiona M. [Department of Radiology, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Department of Imaging, Dana-Farber Cancer Institute, Boston, Massachusetts (United States); D' Amico, Anthony V. [Department of Radiation Oncology, Brigham and Women' s Hospital and Dana-Farber Cancer Institute, Boston, Massachusetts (United States); Tempany, Clare M.C., E-mail: ctempany@bwh.harvard.edu [Division of MRI, Department of Radiology, Brigham and Women' s Hospital, Boston, Massachusetts (United States)

    2013-02-01

    Purpose: To investigate whether 3-T esla (3T) multiparametric endorectal MRI (erMRI) can add information to established predictors regarding occult extraprostatic or high-grade prostate cancer (PC) in men with clinically localized PC. Methods and Materials: At a single academic medical center, this retrospective study's cohort included 118 men with clinically localized PC who underwent 3T multiparametric erMRI followed by radical prostatectomy, from 2008 to 2011. Multivariable logistic regression analyses in all men and in 100 with favorable-risk PC addressed whether erMRI evidence of T3 disease was associated with prostatectomy T3 or Gleason score (GS) 8-10 (in patients with biopsy GS {<=}7) PC, adjusting for age, prostate-specific antigen level, clinical T category, biopsy GS, and percent positive biopsies. Results: The accuracy of erMRI prediction of extracapsular extension and seminal vesicle invasion was 75% and 95%, respectively. For all men, erMRI evidence of a T3 lesion versus T2 was associated with an increased odds of having pT3 disease (adjusted odds ratio [AOR] 4.81, 95% confidence interval [CI] 1.36-16.98, P=.015) and pGS 8-10 (AOR 5.56, 95% CI 1.10-28.18, P=.038). In the favorable-risk population, these results were AOR 4.14 (95% CI 1.03-16.56), P=.045 and AOR 7.71 (95% CI 1.36-43.62), P=.021, respectively. Conclusions: Three-Tesla multiparametric erMRI in men with favorable-risk PC provides information beyond that contained in known preoperative predictors about the presence of occult extraprostatic and/or high-grade PC. If validated in additional studies, this information can be used to counsel men planning to undergo radical prostatectomy or radiation therapy about the possible need for adjuvant radiation therapy or the utility of adding hormone therapy, respectively.

  11. A systematic review of the utility of 1.5 versus 3 Tesla magnetic resonance brain imaging in clinical practice and research

    MRI at 3 T is said to be more accurate than 1.5 T MR, but costs and other practical differences mean that it is unclear which to use. We systematically reviewed studies comparing diagnostic accuracy at 3 T with 1.5 T. We searched MEDLINE, EMBASE and other sources from 1 January 2000 to 22 October 2010 for studies comparing diagnostic accuracy at 1.5 and 3 T in human neuroimaging. We extracted data on methodology, quality criteria, technical factors, subjects, signal-to-noise, diagnostic accuracy and errors according to QUADAS and STARD criteria. Amongst 150 studies (4,500 subjects), most were tiny, compared old 1.5 T with new 3 T technology, and only 22 (15 %) described diagnostic accuracy. The 3 T images were often described as ''crisper'', but we found little evidence of improved diagnosis. Improvements were limited to research applications [functional MRI (fMRI), spectroscopy, automated lesion detection]. Theoretical doubling of the signal-to-noise ratio was not confirmed, mostly being 25 %. Artefacts were worse and acquisitions took slightly longer at 3 T. Objective evidence to guide MRI purchasing decisions and routine diagnostic use is lacking. Rigorous evaluation accuracy and practicalities of diagnostic imaging technologies should be the routine, as for pharmacological interventions, to improve effectiveness of healthcare. (orig.)

  12. Variations of the posterior cerebral artery diagnosed by MR angiography at 3 tesla

    Fenestration, early bifurcation, and duplication of the posterior cerebral artery (PCA) and the so-called hyperplastic anterior choroidal artery (AChA), considered a variation of the PCA, are rare. We evaluated the prevalence and characteristic features of these PCA variations on magnetic resonance (MR) angiography. We reviewed intracranial MR angiographic images of 2402 patients examined using a 3-tesla scanner. Images from the skull base to the intracranial region were obtained using the standard time-of-flight technique. We excluded images of 52 patients with insufficient image quality or occlusion of the PCA(s) and retrospectively evaluated the images of 2350 patients using a picture archiving and communication system. We observed PCA fenestration in eight (0.34 %) patients, most at the P1 segment and P1-P2 junction and all small in size, early bifurcation at the P1-P2 junction or proximal P2A segment in eight (0.34 %) patients, complete duplication in one patient, and hyperplastic AChA in 13 (0.55 %) patients. Eleven of the 13 hyperplastic AChAs supplied only the territory of the temporal branch of the PCA, and the remaining two supplied the entire territory of the PCA. We observed PCA variations in 30 (1.28 %) patients. We believe the name ''hyperplastic AChA'' inaccurately describes variations of the PCA in which the AChA supplies part of or all of the territory of the PCA and propose ''accessory PCA'' to describe an AChA that supplies part of the territory of the PCA or ''replaced PCA'' to describe that vessel that supplies the territory all branches of the PCA. (orig.)

  13. Orbitofrontal lobe volume deficits in Antipsychotic-Naive schizophrenia: A 3-Tesla MRI study

    Behere Rishikesh

    2009-01-01

    Full Text Available Background: Prefrontal cortex deficits have been consistently demonstrated in schizophrenia. The orbitofrontal lobe (OFL, a critical component of the prefrontal cortex, subserves social and neuro-cognitive functions. While these functional impairments are established in schizophrenia, the OFL volume deficits have not been well studied, especially in antipsychotic-naοve patients. Aim: To study OFL volume deficits in antipsychotic-naοve schizophrenia patients in comparison with matched healthy controls using high-resolution 3-tesla (3T magnetic resonance imaging (MRI. Materials and Methods: Fourteen antipsychotic-naοve schizophrenia patients (DSM-IV and 14 age-, sex-, handedness- and education-matched healthy controls were scanned using 3T MRI. Psychopathology was assessed in the patient group using the scale for assessment of negative symptoms and the scale for assessment of positive symptoms (SAPS. The OFL volume was measured using Region of Interest (ROI-based manual morphometry technique, with good inter-rater reliability (intra-class correlation coefficient = 0.98. Results: Total OFL volume was significantly smaller in schizophrenia patients (43.3 ± 9.6 mL in comparison with healthy controls (52.1 ± 12.2 mL after controlling for the potential confounding effects of age, sex and intracranial volume (F = 5.3, P = .03. Duration of untreated psychosis did not correlate significantly with OFL volumes. There was a trend towards significant negative correlation between the left and total OFL volumes and SAPS scores (r = -0.49, P = .06. Conclusion: OFL volume deficits might underlie the pathogenesis of schizophrenia symptoms with possible neuro-developmental origins.

  14. Variations of the posterior cerebral artery diagnosed by MR angiography at 3 tesla

    Uchino, Akira; Saito, Naoko; Takahashi, Masahiro; Okano, Nanami; Tanisaka, Megumi [Saitama Medical University International Medical Center, Department of Diagnostic Radiology, Hidaka, Saitama (Japan)

    2016-02-15

    Fenestration, early bifurcation, and duplication of the posterior cerebral artery (PCA) and the so-called hyperplastic anterior choroidal artery (AChA), considered a variation of the PCA, are rare. We evaluated the prevalence and characteristic features of these PCA variations on magnetic resonance (MR) angiography. We reviewed intracranial MR angiographic images of 2402 patients examined using a 3-tesla scanner. Images from the skull base to the intracranial region were obtained using the standard time-of-flight technique. We excluded images of 52 patients with insufficient image quality or occlusion of the PCA(s) and retrospectively evaluated the images of 2350 patients using a picture archiving and communication system. We observed PCA fenestration in eight (0.34 %) patients, most at the P1 segment and P1-P2 junction and all small in size, early bifurcation at the P1-P2 junction or proximal P2A segment in eight (0.34 %) patients, complete duplication in one patient, and hyperplastic AChA in 13 (0.55 %) patients. Eleven of the 13 hyperplastic AChAs supplied only the territory of the temporal branch of the PCA, and the remaining two supplied the entire territory of the PCA. We observed PCA variations in 30 (1.28 %) patients. We believe the name ''hyperplastic AChA'' inaccurately describes variations of the PCA in which the AChA supplies part of or all of the territory of the PCA and propose ''accessory PCA'' to describe an AChA that supplies part of the territory of the PCA or ''replaced PCA'' to describe that vessel that supplies the territory all branches of the PCA. (orig.)

  15. Clinical Evaluation of Stereotactic Target Localization Using 3-Tesla MRI for Radiosurgery Planning

    Purpose: Increasing the magnetic resonance imaging (MRI) field strength can improve image resolution and quality, but concerns remain regarding the influence on geometric fidelity. The objectives of the present study were to spatially investigate the effect of 3-Tesla (3T) MRI on clinical target localization for stereotactic radiosurgery. Methods and Materials: A total of 39 patients were enrolled in a research ethics board-approved prospective clinical trial. Imaging (1.5T and 3T MRI and computed tomography) was performed after stereotactic frame placement. Stereotactic target localization at 1.5T vs. 3T was retrospectively analyzed in a representative cohort of patients with tumor (n = 4) and functional (n = 5) radiosurgical targets. The spatial congruency of the tumor gross target volumes was determined by the mean discrepancy between the average gross target volume surfaces at 1.5T and 3T. Reproducibility was assessed by the displacement from an averaged surface and volume congruency. Spatial congruency and the reproducibility of functional radiosurgical targets was determined by comparing the mean and standard deviation of the isocenter coordinates. Results: Overall, the mean absolute discrepancy across all patients was 0.67 mm (95% confidence interval, 0.51-0.83), significantly .4), and the gross target volume surface mean displacements were similar within and between users. The overall average isocenter coordinate discrepancy for the functional targets at 1.5T and 3T was 0.33 mm (95% confidence interval, 0.20-0.48), with no patient-specific differences between the mean values (p >.2) or standard deviations (p >.1). Conclusion: Our results have provided clinically relevant evidence supporting the spatial validity of 3T MRI for use in stereotactic radiosurgery under the imaging conditions used.

  16. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - ...

  17. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants pose no ... Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose and treat ...

  18. Magnetic resonance imaging the basics

    Constantinides, Christakis

    2014-01-01

    Magnetic resonance imaging (MRI) is a rapidly developing field in basic applied science and clinical practice. Research efforts in this area have already been recognized with five Nobel prizes awarded to seven Nobel laureates in the past 70 years. Based on courses taught at The Johns Hopkins University, Magnetic Resonance Imaging: The Basics provides a solid introduction to this powerful technology. The book begins with a general description of the phenomenon of magnetic resonance and a brief summary of Fourier transformations in two dimensions. It examines the fundamental principles of physics for nuclear magnetic resonance (NMR) signal formation and image construction and provides a detailed explanation of the mathematical formulation of MRI. Numerous image quantitative indices are discussed, including (among others) signal, noise, signal-to-noise, contrast, and resolution. The second part of the book examines the hardware and electronics of an MRI scanner and the typical measurements and simulations of m...

  19. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose and treat medical ... CD. Currently, MRI is the most sensitive imaging test of the head (particularly the brain) in routine ...

  20. Magnetic Resonance Connectome Automated Pipeline

    Gray, William R.; Bogovic, John A.; Vogelstein, Joshua T; Landman, Bennett A.; Prince, Jerry L.; Vogelstein, R. Jacob

    2011-01-01

    This manuscript presents a novel, tightly integrated pipeline for estimating a connectome, which is a comprehensive description of the neural circuits in the brain. The pipeline utilizes magnetic resonance imaging (MRI) data to produce a high-level estimate of the structural connectivity in the human brain. The Magnetic Resonance Connectome Automated Pipeline (MRCAP) is efficient and its modular construction allows researchers to modify algorithms to meet their specific requirements. The pipe...

  1. Advances in magnetic resonance 2

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 2, features a mixture of experimental and theoretical contributions. The book contains four chapters and begins with an ambitious and general treatment of the problem of signal-to-noise ratio in magnetic resonance. This is followed by separate chapters on the interpretation of nuclear relaxation in fluids, with special reference to hydrogen; and various aspects of molecular theory of importance in NMR.

  2. Advances in magnetic resonance 4

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 4 deals with the relaxation, irradiation, and other dynamical effects that is specific to systems having resolved structure in their magnetic resonance spectra. This book discusses the anisotropic rotation of molecules in liquids by NMR quadrupolar relaxation; rotational diffusion constants; alternating linewidth effect; and theoretical formulations of the problem. The line shapes in high-resolution NMR; matrix representations of the equations of motion; matrix representations of the equations of motion; and intramolecular hydrogen bonds are also delibera

  3. Nuclear magnetic gamma double resonance

    A number of problems corresponding to different variants of experiments using nuclear magnetic-gamma double resonance (NMGDR) are theoretically investigated. Calculation is carried out and its results are compared to experimental ones concerning NMGDR for tantalum. Time dynamics of the source or scatterer nucleus sublevel populations under double resonance conditions with non-uniform initial population of this nucleus sublevels is studied

  4. Combined 3 Tesla MRI Biomarkers Improve the Differentiation between Benign vs Malignant Single Ring Enhancing Brain Masses

    Salice, Simone; Esposito, Roberto; Ciavardelli, Domenico; delli Pizzi, Stefano; di Bastiano, Rossella; Tartaro, Armando

    2016-01-01

    Purpose To evaluate whether the combination of imaging biomarkers obtained by means of different 3 Tesla (3T) Magnetic Resonance Imaging (MRI) advanced techniques can improve the diagnostic accuracy in the differentiation between benign and malignant single ring-enhancing brain masses. Materials and Methods 14 patients presenting at conventional 3T MRI single brain mass with similar appearance as regard ring enhancement, presence of peri-lesional edema and absence of hemorrhage signs were included in the study. All lesions were histologically proven: 5 pyogenic abscesses, 6 glioblastomas, and 3 metastases. MRI was performed at 3 Tesla and included Diffusion Weighted Imaging (DWI), Dynamic Susceptibility Contrast -Perfusion Weighted Imaging (DSC-PWI), Magnetic Resonance Spectroscopy (MRS), and Diffusion Tensor Imaging (DTI). Imaging biomarkers derived by those advanced techniques [Cerebral Blood Flow (CBF), relative Cerebral Blood Volume (rCBV), relative Main Transit Time (rMTT), Choline (Cho), Creatine (Cr), Succinate, N-Acetyl Aspartate (NAA), Lactate (Lac), Lipids, relative Apparent Diffusion Coefficient (rADC), and Fractional Anisotropy (FA)] were detected by two experienced neuroradiologists in joint session in 4 areas: Internal Cavity (IC), Ring Enhancement (RE), Peri-Lesional edema (PL), and Contralateral Normal Appearing White Matter (CNAWM). Significant differences between benign (n = 5) and malignant (n = 9) ring enhancing lesions were tested with Mann-Withney U test. The diagnostic accuracy of MRI biomarkers taken alone and MRI biomarkers ratios were tested with Receiver Operating Characteristic (ROC) analysis with an Area Under the Curve (AUC) ≥ 0.9 indicating a very good diagnostic accuracy of the variable. Results Five MRI biomarker ratios achieved excellent accuracy: IC-rADC/PL-NAA (AUC = 1), IC-rADC/IC-FA (AUC = 0.978), RE-rCBV/RE-FA (AUC = 0.933), IC-rADC/RE-FA (AUC = 0.911), and IC-rADC/PL-FA (AUC = 0.911). Only IC-rADC achieved a very good

  5. Magnetic resonance imaging; Imagerie par resonance magnetique

    Fontanel, F. [Centre Hospitalier, 40 - Mont-de -Marsan (France); Clerc, T. [Centre Hospitalier Universitaire, 76 - Rouen (France); Theolier, S. [Hospice Civils de Lyon, 69 - Lyon (France); Verdenet, J. [Centre Hospitalier Universitaire, 25 - Besancon (France)

    1997-04-01

    The last improvements in nuclear magnetic resonance imaging are detailed here, society by society with an expose of their different devices. In the future the different technological evolutions will be on a faster acquisition, allowing to reduce the examination time, on the development of a more acute cardiac imaging, of a functional neuro-imaging and an interactive imaging for intervention. With the contrast products, staying a longer time in the vascular area, the angiography will find its place. Finally, the studies on magnetic fields should allow to increase the volume to examine. (N.C.).

  6. Magnetic Resonance Imaging of Thoracic Aortic Dissections

    Sax, Steven L.

    1990-01-01

    Magnetic resonance imaging is an excellent noninvasive method for evaluating thoracic aortic dissections. A variety of magnetic resonance scans of aortic dissections are shown, documenting the ability of magnetic resonance to image the true lumen, the false channel, and the intimal septum. Detail is provided on magnetic resonance imaging techniques and findings. (Texas Heart Institute Journal 1990;17:262-70)

  7. Advances in magnetic resonance 5

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 5 deals with the interpretation of ESR spectra and provides descriptions of experimental apparatus. This book discusses the halogen hyperfine interactions; organic radicals in single crystals; pulsed-Fourier-transform nuclear magnetic resonance spectrometer; and inhomogenizer and decoupler. The spectrometers for multiple-pulse NMR; weak collision theory of relaxation in the rotating frame; and spin Hamiltonian for the electron spin resonance of irradiated organic single crystals are also deliberated. This text likewise covers the NMR in helium three and m

  8. Magnetic resonance imaging in posterior circulation infarction: impact on diagnosis and management

    To compare the diagnostic yield of magnetic resonance imaging (MRI) with computed tomography (CT) in posterior circulation infarction, we used proton MRI with a 0.3 Tesla magnet and a 3rd generation CT scanner in 25 patients. Age-matched controls were compared in a blinded fashion. Seventeen patients (68%) showed relevant pathology on MRI not seen on CT, 11 with normal CT and six with more extensive lesions, chiefly in the brain stem. Evidence of abnormal vertebrobasilar blood flow was seen in 8/25 (32%) of patients, suggested by vascular high intensity signals on MRI. Two tissue and one flow abnormality were seen in the control group. MRI provides additional information concerning infarct site, extent and pathogenesis in posterior circulation infarction. 21 refs., 5 figs., 3 tabs

  9. Magnetic resonance and porous materials

    Mention the words magnetic resonance to your medical advisor and he or she will immediately think of a multi-million pound scanner that peers deep into the brain. A chemist, on the other hand, will imagine a machine that costs several hundred thousand pounds and produces high-resolution spectra for chemical analysis. Food technologists will probably think of a bench-top instrument for determining moisture content, while an oil prospector will envisage a device that can be operated several kilometres down an oil well. To a physicist the term is more likely to conjure up a mental picture of nuclear spins precessing in a magnetic field. These examples illustrate the diverse aspects of a phenomenon discovered by physicists over 50 years ago. Electron spin resonance was first discovered by Russian scientists, and nuclear magnetic resonance was discovered in the US shortly afterwards by Ed Purcell at Harvard University and Felix Bloch at Stanford University. Today, nuclear magnetic resonance (NMR) is the most widely used technique. Modern NMR machines are making it possible to probe microstructure and molecular movement in materials as diverse as polymers, cements, rocks, soil and foods. NMR allows the distribution of different components in a material to be determined with a resolution approaching 1μm, although the signal can be sensitive to even smaller lengthscales. In this article the authors describe how physicists are still developing magnetic resonance to exploit a range of new applications. (UK)

  10. GHz nuclear magnetic resonance

    Cross, T.A.; Drobny, G.; Trewhella, J.

    1994-12-01

    For the past dozen years, 500- and 600-MHz spectrometers have become available in many laboratories. The first 600-MHz NMR spectrometer (at Carnegie Mellon University) was commissioned more than 15 years ago and, until 1994, represented the highest field available for high-resolution NMR. This year, we have witnessed unprecedented progress in the development of very high field magnets for NMR spectroscopy, including the delivery of the first commercial 750-MHz NMR spectrometers. In addition, NMR signals have been obtained from 20-Tesla magnets (850 MHz for {sup 1}H`s) at both Los Alamos National Laboratory and Florida State University in the NHMFL (National High Magnetic Field Laboratory). These preliminary experiments have been performed in magnets with 100-ppm homogeneity, but a 20-Tesla magnet developed for the NHMFL will be brought to field this year with a projected homogeneity of 0.1 ppm over a 1-cm-diam spherical volume.

  11. Quantitative Magnetic Resonance Imaging of Cortical Multiple Sclerosis Pathology

    Christine L. Tardif

    2012-01-01

    Full Text Available Although significant improvements have been made regarding the visualization and characterization of cortical multiple sclerosis (MS lesions using magnetic resonance imaging (MRI, cortical lesions (CL continue to be under-detected in vivo, and we have a limited understanding of the causes of GM pathology. The objective of this study was to characterize the MRI signature of CLs to help interpret the changes seen in vivo and elucidate the factors limiting their visualization. A quantitative 3D high-resolution (350 μm isotropic MRI study at 3 Tesla of a fixed post mortem cerebral hemisphere from a patient with MS is presented in combination with matched immunohistochemistry. Type III subpial lesions are characterized by an increase in T1, T2 and M0, and a decrease in MTR in comparison to the normal appearing cortex (NAC. All quantitative MR parameters were associated with cortical GM myelin content, while T1 showed the strongest correlation. The histogram analysis showed extensive overlap between CL and NAC for all MR parameters and myelin content. This is due to the poor contrast in myelin content between CL and NAC in comparison to the variability in myelo-architecture throughout the healthy cortex. This latter comparison is highlighted by the representation of T1 times on cortical surfaces at several laminar depths.

  12. Recommendations concerning magnetic resonance spectroscopy

    In medicine the technique of nuclear magnetic resonance (NMR) is applied in the form of in vivo nuclear magnetic resonance spectroscopy (MRS). In vivo MRS can be carried out non-invasively. The committee of the Dutch Health Council briefly discusses the qualities and potentialities of the nuclei that will probably be used in future clinical spectroscopy: 31P, 13C, 1H (and possibly 19F and 23Na). The committee discusses several possibilities of combining imaging and spectroscopy. The imaging of nuclei other than protons is also possible with MRS. Potential applications are considered in oncology, cardiology, neurology and hepatology. (Auth.)

  13. magnetic resonance imaging,etc.

    张福基

    1998-01-01

    magnetic resonance imaging n.[1984] a noninvasive diagnostic technique that produces computerized images of internal body tissues and is based on nuclear magnetic resonance of atoms within he body induced by the application of radio waves磁共振成像(指一种非侵害 性诊断技术,能生成内部身体组织的计算机化影像,其依据是应用无线电波 感生体内原子并使之产磁共振)

  14. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - ... into the bloodstream. The radiologist , technologist or a nurse may ask if you have allergies of any ...

  15. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... structures of the brain and can also provide functional information (fMRI) in selected cases. MR images of ... Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain ...

  16. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Magnetic Resonance ... allergic reaction than iodinated contrast material. Tell your doctor about any health problems, recent surgeries or allergies ...

  17. Chemical exchange saturation transfer MR imaging of Parkinson's disease at 3 Tesla

    To demonstrate the feasibility of using chemical exchange saturation transfer (CEST) imaging to detect Parkinson's disease (PD) in patients at 3 Tesla. Twenty-seven PD patients (17 men and 10 women; age range, 54-77 years) and 22 age-matched normal controls (13 men and 9 women; age range, 55-73 years) were examined on a 3-Tesla MRI system. Magnetization transfer spectra with 31 different frequency offsets (-6 to 6 ppm) were acquired at two transverse slices of the head, including the basal ganglia and midbrain. One-way analysis of variance tests was used to compare the differences in CEST imaging signals between PD patients and normal controls. Total CEST signal between the offsets of 0 and 4 ppm in the substantia nigra was significantly lower in PD patients than in normal controls (P = 0.006), which could be associated with the loss of dopaminergic neurons. Protein-based CEST imaging signals at the offset of 3.5 ppm in the globus pallidus, putamen and caudate were significantly increased in PD patients, compared to normal controls (P < 0.001, P = 0.003, P < 0.001, respectively). CEST imaging signals could potentially serve as imaging biomarkers to aid in the non-invasive molecular diagnosis of PD. (orig.)

  18. Chemical exchange saturation transfer MR imaging of Parkinson's disease at 3 Tesla

    Li, Chunmei; Peng, Shuai; Wang, Rui; Chen, Min [Beijing Hospital, Department of Radiology, Beijing (China); Chen, Haibo; Su, Wen [Beijing Hospital, Department of Neurology, Beijing (China); Zhao, Xuna [Peking University, Center for MRI Research and Beijing City Key Lab for Medical Physics and Engineering, Beijing (China); Zhou, Jinyuan [Johns Hopkins University, Department of Radiology, Baltimore, MD (United States)

    2014-10-15

    To demonstrate the feasibility of using chemical exchange saturation transfer (CEST) imaging to detect Parkinson's disease (PD) in patients at 3 Tesla. Twenty-seven PD patients (17 men and 10 women; age range, 54-77 years) and 22 age-matched normal controls (13 men and 9 women; age range, 55-73 years) were examined on a 3-Tesla MRI system. Magnetization transfer spectra with 31 different frequency offsets (-6 to 6 ppm) were acquired at two transverse slices of the head, including the basal ganglia and midbrain. One-way analysis of variance tests was used to compare the differences in CEST imaging signals between PD patients and normal controls. Total CEST signal between the offsets of 0 and 4 ppm in the substantia nigra was significantly lower in PD patients than in normal controls (P = 0.006), which could be associated with the loss of dopaminergic neurons. Protein-based CEST imaging signals at the offset of 3.5 ppm in the globus pallidus, putamen and caudate were significantly increased in PD patients, compared to normal controls (P < 0.001, P = 0.003, P < 0.001, respectively). CEST imaging signals could potentially serve as imaging biomarkers to aid in the non-invasive molecular diagnosis of PD. (orig.)

  19. Magnetometer of nuclear magnetic resonance

    We present a nuclear magnetic resonance magnetometer that measures magnetic fields, between 2,500 gauss and 5,000 gauss, with an accuracy of a few parts per million. The circuit of the magnetometer, based on a marginal oscillator, permits a continuous tunning in the frequency range comprised between 10.0 MHz, with a signal to noise ratio of about 20. The radiofrequency amplifier is of the cascode type in integrated circuit and it operates with two 9V batteries. The modulation is at 35 Hz and it is provided by an external oscillator. The instrument is compact, inexpensive and easy to operate; it can also be used for didactic purposes to show the phenomenon of magnetic nuclear resonance and its main characteristics. (author)

  20. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    ... produced by: Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA ...

  1. Advances in magnetic and optical resonance

    Warren, Warren S

    1997-01-01

    Since 1965, Advances in Magnetic and Optical Resonance has provided researchers with timely expositions of fundamental new developments in the theory of, experimentation with, and application of magnetic and optical resonance.

  2. Iron oxide nanorods as high-performance magnetic resonance imaging contrast agents

    Mohapatra, Jeotikanta; Mitra, Arijit; Tyagi, Himanshu; Bahadur, D.; Aslam, M.

    2015-05-01

    An efficient magnetic resonance imaging (MRI) contrast agent with a high R2 relaxivity value is achieved by controlling the shape of iron oxide to rod like morphology with a length of 30-70 nm and diameter of 4-12 nm. Fe3O4 nanorods of 70 nm length, encapsulated with polyethyleneimine show a very high R2 relaxivity value of 608 mM-1 s-1. The enhanced MRI contrast of nanorods is attributed to their higher surface area and anisotropic morphology. The higher surface area induces a stronger magnetic field perturbation over a larger volume more effectively for the outer sphere protons. The shape anisotropy contribution is understood by calculating the local magnetic field of nanorods and spherical nanoparticles under an applied magnetic field (3 Tesla). As compared to spherical geometry, the induced magnetic field of a rod is stronger and hence the stronger magnetic field over a large volume leads to a higher R2 relaxivity of nanorods.An efficient magnetic resonance imaging (MRI) contrast agent with a high R2 relaxivity value is achieved by controlling the shape of iron oxide to rod like morphology with a length of 30-70 nm and diameter of 4-12 nm. Fe3O4 nanorods of 70 nm length, encapsulated with polyethyleneimine show a very high R2 relaxivity value of 608 mM-1 s-1. The enhanced MRI contrast of nanorods is attributed to their higher surface area and anisotropic morphology. The higher surface area induces a stronger magnetic field perturbation over a larger volume more effectively for the outer sphere protons. The shape anisotropy contribution is understood by calculating the local magnetic field of nanorods and spherical nanoparticles under an applied magnetic field (3 Tesla). As compared to spherical geometry, the induced magnetic field of a rod is stronger and hence the stronger magnetic field over a large volume leads to a higher R2 relaxivity of nanorods. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00055f

  3. Optically detected magnetic resonance imaging

    Optically detected magnetic resonance provides ultrasensitive means to detect and image a small number of electron and nuclear spins, down to the single spin level with nanoscale resolution. Despite the significant recent progress in this field, it has never been combined with the power of pulsed magnetic resonance imaging techniques. Here, we demonstrate how these two methodologies can be integrated using short pulsed magnetic field gradients to spatially encode the sample. This result in what we denote as an 'optically detected magnetic resonance imaging' technique. It offers the advantage that the image is acquired in parallel from all parts of the sample, with well-defined three-dimensional point-spread function, and without any loss of spectroscopic information. In addition, this approach may be used in the future for parallel but yet spatially selective efficient addressing and manipulation of the spins in the sample. Such capabilities are of fundamental importance in the field of quantum spin-based devices and sensors

  4. Resonant magnetic fields from inflation

    We propose a novel scenario to generate primordial magnetic fields during inflation induced by an oscillating coupling of the electromagnetic field to the inflaton. This resonant mechanism has two key advantages over previous proposals. First of all, it generates a narrow band of magnetic fields at any required wavelength, thereby allaying the usual problem of a strongly blue spectrum and its associated backreaction. Secondly, it avoids the need for a strong coupling as the coupling is oscillating rather than growing or decaying exponentially. Despite these major advantages, we find that the backreaction is still far too large during inflation if the generated magnetic fields are required to have a strength of O(10−15 Gauss) today on observationally interesting scales. We provide a more general no-go argument, proving that this problem will apply to any model in which the magnetic fields are generated on subhorizon scales and freeze after horizon crossing

  5. Ventricular Assist Device implant (AB 5000 prototype cannula: In vitro assessment of MRI issues at 3-Tesla

    Valencerina Samuel

    2008-05-01

    Full Text Available Abstract Purpose To evaluate MRI issues at 3-Tesla for a ventricular assist device (VAD. Methods The AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached (Abiomed, Inc., Danvers, MA was evaluated for magnetic field interactions, heating, and artifacts at 3-Tesla. MRI-related heating was assessed with the device in a gelled-saline-filled, head/torso phantom using a transmit/received RF body coil while performing MRI at a whole body averaged SAR of 3-W/kg for 15-min. Artifacts were assessed for the main metallic component of this VAD (atrial cannula using T1-weighted, spin echo and gradient echo pulse sequences. Results The AB5000 Ventricle with the prototype In-Flow Cannula and Out-Flow Cannula attached showed relatively minor magnetic field interactions that will not cause movement in situ. Heating was not excessive (highest temperature change, +0.8°C. Artifacts may create issues for diagnostic imaging if the area of interest is in the same area or close to the implanted metallic component of this VAD (i.e., the venous cannula. Conclusion The results of this investigation demonstrated that it would be acceptable for a patient with this VAD (AB5000 Ventricle with a prototype Nitinol wire-reinforced In-Flow Cannula and Out-Flow Cannula attached to undergo MRI at 3-Tesla or less. Notably, it is likely that the operation console for this device requires positioning a suitable distance (beyond the 100 Gauss line or in the MR control room from the 3-Tesla MR system to ensure proper function of the VAD.

  6. Pediatric Body Magnetic Resonance Imaging.

    Kandasamy, Devasenathipathy; Goyal, Ankur; Sharma, Raju; Gupta, Arun Kumar

    2016-09-01

    Magnetic resonance imaging (MRI) is a radiation-free imaging modality with excellent contrast resolution and multiplanar capabilities. Since ionizing radiation is an important concern in the pediatric population, MRI serves as a useful alternative to computed tomography (CT) and also provides additional clues to diagnosis, not discernible on other investigations. Magnetic resonance cholangiopancreatography (MRCP), urography, angiography, enterography, dynamic multiphasic imaging and diffusion-weighted imaging provide wealth of information. The main limitations include, long scan time, need for sedation/anesthesia, cost and lack of widespread availability. With the emergence of newer sequences and variety of contrast agents, MRI has become a robust modality and may serve as a one-stop shop for both anatomical and functional information. PMID:26916887

  7. Evanescent Waves Nuclear Magnetic Resonance

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad;

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to char...... a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging....

  8. Tomography by nuclear magnetic resonance

    Imaging methods based on nuclear magnetic resonance allow the production of sectional images of the human body without ionizing radiation. It is possible to measure the density and relaxation times of the water protons in body fluids or tissue. This allows not only to obtain morphological information but also to get some insight into the spatial distribution of physiological data. Starting with a review of the principles of nuclear magnetic resonance it is explained how the measured signal can be associated with an image point; it is also explained what type of apparatus is necessary and what the physical limitations are. Possible risks the patient may be exposed to in an examination using nuclear magnetic resonance are discussed. The present state of the technical development enables the production of whole-body sectional images of a living person within about one minute. By means of some typical examples the nature and properties of these images are explained. Although extensive clinical studies will be necessary before a more general assessment can be made of this method, an outlook is provided on expected further developments and possible future fields of application. (orig.)

  9. Magnetic Resonance Force Detection using a Membrane Resonator

    Scozzaro, Nicolas; Ruchotzke, Will; Belding, Amanda; Cardellino, Jeremy D.; Blomberg, Erick C.; McCullian, Brendan A.; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Hammel, P. Chris

    2016-01-01

    The availability of compact, low-cost magnetic resonance imaging instruments would further broaden the substantial impact of this technology. We report highly sensitive detection of magnetic resonance using low-stress silicon nitride (SiN$_x$) membranes. We use these membranes as low-loss, high-frequency mechanical oscillators and find they are able to mechanically detect spin-dependent forces with high sensitivity enabling ultrasensitive magnetic resonance detection. The high force detection...

  10. Ultra-high frequency magnetic resonance imaging

    Magill, Arthur W.

    2007-01-01

    This thesis addresses the problem of radiofrequency probe design for Ultra High Frequency Magnetic Resonance Imaging (7T). The signal-to-noise ratio available in Magnetic Resonance Imaging (MRI) is determined by the static magnetic field strength, causing a continued drive toward higher fields to enable faster image acquisition at finer spatial resolution. The resonant frequency increases linearly with static field strength. At 7T the proton resonant frequency is 300MHz, with a wavelength...

  11. Initial Experience of 3-Tesla Apparent Diffusion Coefficient Values in Characterizing Squamous Cell Carcinomas of the Head and Neck

    Background: With the increased clinical use of 3-Tesla (3T) magnets, it becomes important to identify the potential applications of advanced magnetic resonance (MR) imaging techniques such as diffusion-weighted imaging in head and neck pathologies. Purpose: To establish the 3T apparent diffusion coefficient (ADC) values for normal neck structures, and to examine the utility of ADC values in distinguishing head and neck squamous cell carcinomas (HNSCC) from normal neck anatomy. Material and Methods: 3T diffusion-weighted imaging was performed on 10 normal volunteers and 10 patients with known HNSCC. In the volunteers, mean ADC was calculated in the parotid gland, submandibular gland, base of the tongue, pterygoid muscle, masseter muscle, paraspinal muscles, true vocal cord, thyroid gland, thyroid cartilage, cricoid cartilage, and lymph nodes. The mean tumor ADC value was calculated from the 10 patients with HNSCC and compared with the normal ADC values from various neck structures. Results: The mean ADC value measured in the HNSCC was 1.101 (±0.214)x10-3mm2/s. This was significantly lower than ADC values of paraspinal muscles, pterygoid muscle, masseter muscle, thyroid gland, and base of the tongue (P=0.0006, 0.0002, 0.0001, 0.001, and 0.002, respectively). The tumor ADC values were not significantly different from ADC values of parotid and submandibular glands (P=0.057 and 0.14, respectively). Conclusion: 3T ADC values show potential for distinguishing HNSCC from normal extracranial head and neck structures

  12. Magnetic resonance imaging in oncology

    Nuclear magnetic resonance (NMR) employs radio-frequency radiation in the presence of a static magnetic field to produce signals from naturally occurring nuclei in biological tissue. The information in magnetic resonance imaging (MRI) can be derived from these signals in any orthogonal plane. Hydrogen is the most abundant of such nuclei, occurring naturally in water and lipid, and can be detected at relatively low magnetic field strength (0.04 tesla (T) upwards). The MR signal from hydrogen depends not only on the proton density and the T1 and T2 relaxation times of those protons following radio-frequency pulse disturbances, but also on the timing parameters of the radio-frequency pulse sequences employed. Image contrast depends on the interaction between all these factors; not simply as in X-ray computed tomography (CT) on the properties of the tissue itself. Therefore an understanding of both the imaging process and the pathology under investigation is essential in the proper use of MRI

  13. Pediatric case report on magnetic resonance imaging/transrectal ultrasound-fusion biopsy of rhabdomyosarcoma of the bladder/prostate: a new tool to reduce therapy-associated morbidity?

    Kuru, Timur H; Roethke, Matthias C; Nyarangi-Dix, Joanne; Okouoyo, Stella; Stockklausner, Clemens; Schenk, Jens-Peter; Debus, Jürgen; Roth, Wilfried; Teber, Dogu; Pahernik, Sascha; Schlemmer, Heinz-Peter; Hohenfellner, Markus; Hadaschik, Boris A

    2013-02-01

    Rhabdomyosarcomas are the most common soft tissue sarcomas in children. Here we present management of an 18-month-old boy with metastatic rhabdomyosarcoma of the bladder/prostate. After radiochemotherapy, high-spatial-resolution 3-Tesla multiparametric magnetic resonance imaging (MRI) showed regressive systemic disease but a residual mass at the right seminal vesicle. For histologic re-evaluation, 3-dimensional-controlled stereotactic MRI/transrectal ultrasound (TRUS)-fusion biopsy specimens were taken. Because histologic analysis showed nonvital tissue, a decision could be made against adjuvant radical cystoprostatectomy. Advanced 3-Tesla imaging and MRI/TRUS-fusion biopsies in children are feasible and represent an effective tool to examine suspicious pelvic lesions. Depending on histology, this can lead to a significant reduction of therapy-associated morbidity. PMID:23374821

  14. Fast magnetization reversal of nanoclusters in resonator

    Yukalov, V. I.; Yukalova, E. P.

    2012-01-01

    An effective method for ultrafast magnetization reversal of nanoclusters is suggested. The method is based on coupling a nanocluster to a resonant electric circuit. This coupling causes the appearance of a magnetic feedback field acting on the cluster, which drastically shortens the magnetization reversal time. The influence of the resonator properties, nanocluster parameters, and external fields on the magnetization dynamics and reversal time is analyzed. The magnetization reversal time can ...

  15. Wide-range nuclear magnetic resonance detector

    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.

  16. Cortical microinfarcts detected in vivo on 3 tesla MRI : Clinical and radiological correlates

    Van Dalen, Jan Willem; Scuric, Eva E M; Van Veluw, Susanne J.; Caan, Matthan W A; Nederveen, Aart J.; Biessels, Geert Jan; Van Gool, Willem A.; Richard, Edo

    2015-01-01

    Background and Purpose-Cortical microinfarcts (CMIs) are a common postmortem finding associated with vascular risk factors, cognitive decline, and dementia. Recently, CMIs identified in vivo on 7 Tesla MRI also proved retraceable on 3 Tesla MRI. Methods-We evaluated CMIs on 3 Tesla MRI in a populati

  17. Cortical microinfarcts detected in vivo on 3 Tesla MRI: clinical and radiological correlates

    Dalen, J.W. van; Scuric, E.E.; Veluw, S.J. van; Caan, M.W.; Nederveen, A.J.; Biessels, G.J.; Gool, W.A. van; Richard, E.

    2015-01-01

    BACKGROUND AND PURPOSE: Cortical microinfarcts (CMIs) are a common postmortem finding associated with vascular risk factors, cognitive decline, and dementia. Recently, CMIs identified in vivo on 7 Tesla MRI also proved retraceable on 3 Tesla MRI. METHODS: We evaluated CMIs on 3 Tesla MRI in a popula

  18. Evanescent Waves Nuclear Magnetic Resonance.

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad; Kenouche, Samir; Coillot, Christophe; Alibert, Eric; Jabakhanji, Bilal; Schimpf, Remy; Zanca, Michel; Stein, Paul; Goze-Bac, Christophe

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to characterize and model evanescent electromagnetic fields originating from NMR phenomenon. We report that in this experimental configuration the available NMR signal is one order of magnitude larger and follows an exponential decay inversely proportional to the size of the emitters. Those investigations open a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging. PMID:26751800

  19. Hyperpolarized Renal Magnetic Resonance Imaging

    Laustsen, Christoffer

    2016-01-01

    The introduction of dissolution dynamic nuclear polarization (d-DNP) technology has enabled a new paradigm for renal imaging investigations. It allows standard magnetic resonance imaging complementary renal metabolic and functional fingerprints within seconds without the use of ionizing radiation....... Increasing evidence supports its utility in preclinical research in which the real-time interrogation of metabolic turnover can aid the physiological and pathophysiological metabolic and functional effects in ex vivo and in vivo models. The method has already been translated to humans, although the clinical...

  20. Advances in magnetic resonance 3

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 3, describes a number of important developments which are finding increasing application by chemists. The book contains five chapters and begins with a discussion of how the properties of random molecular rotations reflect themselves in NMR and how they show up, often differently, in other kinds of experiments. This is followed by separate chapters on the Kubo method, showing its equivalence to the Redfield approach in the cases of most general interest; the current state of dynamic nuclear polarization measurements in solutions and what they tell us abou

  1. Sensitivity of an eight-element phased array coil in 3 Tesla MR imaging. A basic analysis

    The purpose of this study was to evaluate the performance advantages of an 8-element phased array head coil (8 ch coil) over a conventional quadrature-type birdcage head coil (QD coil) with regard to the signal-to-noise ratio (SNR) and image uniformity in 3 Tesla magnetic resonance (MR) imaging. We scanned a phantom filled with silicon oil using an 8 ch coil and a QD coil in a 3T MR imaging system and compared the SNR and image uniformity obtained from T1-weighted spin echo (SE) images and T2-weighted fast SE images between the 2 coils. We also visually evaluated images from 4 healthy volunteers. The SNR with the 8 ch coil was approximately twice that with the QD coil in the region of interest (ROI), which was set as 75% of the area in the center of the phantom images. With regard to the spatial variation of sensitivity, the SNR with the 8 ch coil was lower at the center of the images than at the periphery, whereas the SNR with the QD coil exhibited an inverse pattern. At the center of the images with the 8 ch coil, the SNR was somewhat lower, and that distribution was relatively flat compared to that in the periphery. Image uniformity varied less with the 8 ch coil than with the QD coil on both imaging sequences. The 8 ch phased array coil was useful for obtaining high quality 3T images because of its higher SNR and improved image uniformity than those obtained with conventional quadrature-type birdcage head coil. (author)

  2. Tunable Magnetic Resonance in Microwave Spintronics Devices

    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.

  3. Cerebellar hemangioblastoma: magnetic resonance findings

    To characterize the results of magnetic resonance imaging in cerebellar hemangioblastoma. This retrospective study deals with seven cases of histologically-confirmed cerebellar hemangioblastoma after surgery. Another patient, diagnosed as having Von Hippel-Lindau disease, also developed this lesions, but the finding was not histologically confirmed. In all, there were 2 women and 6 men. Three of these patients presented Von Hippel-Lindaus disease. All were studied on a 0.5 T imager with T1, T2 and PD-weighted spin-echo axial planes; T1-weighted sequences were repeated after intravenous gadolinium administration. According to their aspects, the lesions were divided into three groups as follows: cyst containing a mural nodule (n=3)solid tumor (n=3) and cavitated tumor (n=1). In one patient, the lesion was initially solid and was found to present cavitation two years later. Abnormal vascularization was observed in all the tumors except for two small solid tumors, and the findings were not clear in one of the cysts containing a mural nodule. In the differential diagnosis it may be difficult to rule out other tumors, such as cystic astrocytoma. However, magnetic resonance imaging, together with the clinical data, is of diagnostic value in the three morphological types of cerebellar hemangioblastoma. (Author) 15 refs

  4. Magnetic resonance imaging of hemochromatosis arthropathy

    This study was undertaken to compare plain film radiography and magnetic resonance imaging in the assessment of hemochromatosis arthropathy of the knees of ten patients with a biopsy-proven diagnosis. Both modalities enabled visualisation of bony degenerative changes; magnetic resonance imaging enabled additional visualization of deformity of both cartilage and menisci. Magnetic resonance imaging failed reliably to confirm the presence of intra-articular iron in the patients studied. No correlation was observed between synovial fluid magnetic resonance signal values, corresponding serum ferritin levels, or the severity of the observed degenerative changes. (orig.)

  5. Society for Cardiovascular Magnetic Resonance guidelines for reporting cardiovascular magnetic resonance examinations

    van Rossum Albert C; Raman Subha V; McConnell Michael V; Lawson Mark A; Higgins Charles B; Friedrich Matthias G; Bogaert Jan G; Bluemke David; Hundley W Gregory; Flamm Scott; Kramer Christopher M; Nagel Eike; Neubauer Stefan

    2009-01-01

    Abstract These reporting guidelines are recommended by the Society for Cardiovascular Magnetic Resonance (SCMR) to provide a framework for healthcare delivery systems to disseminate cardiac and vascular imaging findings related to the performance of cardiovascular magnetic resonance (CMR) examinations.

  6. BOLD cardiovascular magnetic resonance at 3.0 tesla in myocardial ischemia

    Gebker Rolf

    2010-09-01

    Full Text Available Abstract Background The purpose of this study was to determine the ability of Blood Oxygen Level Dependent (BOLD cardiovascular magnetic resonance (CMR to detect stress-inducible myocardial ischemic reactions in the presence of angiographically significant coronary artery disease (CAD. Methods Forty-six patients (34 men; age 65 ± 9 years, with suspected or known coronary artery disease underwent CMR at 3Tesla prior to clinically indicated invasive coronary angiography. BOLD CMR was performed in 3 short axis slices of the heart at rest and during adenosine stress (140 μg/kg/min followed by late gadolinium enhancement (LGE imaging. In all 16 standard myocardial segments, T2* values were derived at rest and under adenosine stress. Quantitative coronary angiography served as the standard of reference and defined normal myocardial segments (i.e. all 16 segments in patients without any CAD, ischemic segments (i.e. supplied by a coronary artery with ≥50% luminal narrowing and non-ischemic segments (i.e. supplied by a non-significantly stenosed coronary artery in patients with significant CAD. Results Coronary angiography demonstrated significant CAD in 23 patients. BOLD CMR at rest revealed significantly lower T2* values for ischemic segments (26.7 ± 11.6 ms compared to normal (31.9 ± 11.9 ms; p Conclusions Rest and stress BOLD CMR at 3Tesla proved feasible and differentiated between ischemic, non-ischemic, and normal myocardial segments in a clinical patient population. BOLD CMR during vasodilator stress identified patients with significant CAD.

  7. Hyperpolarized Xenon-129 Magnetic Resonance Imaging of Functional Lung Microstructure

    Dregely, Isabel

    Hyperpolarized 129Xe (HXe) is a non-invasive contrast agent for lung magnetic resonance imaging (MRI), which upon inhalation follows the functional pathway of oxygen in the lung by dissolving into lung tissue structures and entering the blood stream. HXe MRI therefore provides unique opportunities for functional lung imaging of gas exchange which occurs from alveolar air spaces across the air-blood boundary into parenchymal tissue. However challenges in acquisition speed and signal-to-noise ratio have limited the development of a HXe imaging biomarker to diagnose lung disease. This thesis addresses these challenges by introducing parallel imaging to HXe MRI. Parallel imaging requires dedicated hardware. This work describes design, implementation, and characterization of a 32-channel phased-array chest receive coil with an integrated asymmetric birdcage transmit coil tuned to the HXe resonance on a 3 Tesla MRI system. Using the newly developed human chest coil, a functional HXe imaging method, multiple exchange time xenon magnetization transfer contrast (MXTC) is implemented. MXTC dynamically encodes HXe gas exchange into the image contrast. This permits two parameters to be derived regionally which are related to gas-exchange functionality by characterizing tissue-to-alveolar-volume ratio and alveolar wall thickness in the lung parenchyma. Initial results in healthy subjects demonstrate the sensitivity of MXTC by quantifying the subtle changes in lung microstructure in response to orientation and lung inflation. Our results in subjects with lung disease show that the MXTC-derived functional tissue density parameter exhibits excellent agreement with established imaging techniques. The newly developed dynamic parameter, which characterizes the alveolar wall, was elevated in subjects with lung disease, most likely indicating parenchymal inflammation. In light of these observations we believe that MXTC has potential as a biomarker for the regional quantification of 1

  8. Diagnosis of rotator cuff tears using 3-Tesla MRI versus 3-Tesla MRA: a systematic review and meta-analysis

    To compare the diagnostic accuracy of magnetic resonance imaging (MRI), 2-dimensional magnetic resonance arthrogram (MRA) and 3-dimensional isotropic MRA in the diagnosis of rotator cuff tears when performed exclusively at 3-T. A systematic review was undertaken of the Cochrane, MEDLINE and PubMed databases in accordance with the PRISMA guidelines. Studies comparing 3-T MRI or 3-T MRA (index tests) to arthroscopic surgical findings (reference test) were included. Methodological appraisal was performed using QUADAS 2. Pooled sensitivity and specificity were calculated and summary receiver-operating curves generated. Kappa coefficients quantified inter-observer reliability. Fourteen studies comprising 1332 patients were identified for inclusion. Twelve studies were retrospective and there were concerns regarding index test bias and applicability in nine and six studies respectively. Reference test bias was a concern in all studies. Both 3-T MRI and 3-T MRA showed similar excellent diagnostic accuracy for full-thickness supraspinatus tears. Concerning partial-thickness supraspinatus tears, 3-T 2D MRA was significantly more sensitive (86.6 vs. 80.5 %, p = 0.014) but significantly less specific (95.2 vs. 100 %, p < 0.001). There was a trend towards greater accuracy in the diagnosis of subscapularis tears with 3-T MRA. Three-Tesla 3D isotropic MRA showed similar accuracy to 3-T conventional 2D MRA. Three-Tesla MRI appeared equivalent to 3-T MRA in the diagnosis of full- and partial-thickness tears, although there was a trend towards greater accuracy in the diagnosis of subscapularis tears with 3-T MRA. Three-Tesla 3D isotropic MRA appears equivalent to 3-T 2D MRA for all types of tears. (orig.)

  9. Diagnosis of rotator cuff tears using 3-Tesla MRI versus 3-Tesla MRA: a systematic review and meta-analysis

    McGarvey, Ciaran; Harb, Ziad; Smith, Christian; Ajuied, Adil [Guy' s and St Thomas' Hospital, King' s Health Partners, Department of Trauma and Orthopaedics, London (United Kingdom); Houghton, Russell [Guy' s and St Thomas' Hospital, King' s Health Partners, Department of Radiology, London (United Kingdom); Corbett, Steven [Guy' s and St Thomas' Hospital, King' s Health Partners, Department of Trauma and Orthopaedics, London (United Kingdom); Fortius Clinic, London (United Kingdom)

    2016-02-15

    To compare the diagnostic accuracy of magnetic resonance imaging (MRI), 2-dimensional magnetic resonance arthrogram (MRA) and 3-dimensional isotropic MRA in the diagnosis of rotator cuff tears when performed exclusively at 3-T. A systematic review was undertaken of the Cochrane, MEDLINE and PubMed databases in accordance with the PRISMA guidelines. Studies comparing 3-T MRI or 3-T MRA (index tests) to arthroscopic surgical findings (reference test) were included. Methodological appraisal was performed using QUADAS 2. Pooled sensitivity and specificity were calculated and summary receiver-operating curves generated. Kappa coefficients quantified inter-observer reliability. Fourteen studies comprising 1332 patients were identified for inclusion. Twelve studies were retrospective and there were concerns regarding index test bias and applicability in nine and six studies respectively. Reference test bias was a concern in all studies. Both 3-T MRI and 3-T MRA showed similar excellent diagnostic accuracy for full-thickness supraspinatus tears. Concerning partial-thickness supraspinatus tears, 3-T 2D MRA was significantly more sensitive (86.6 vs. 80.5 %, p = 0.014) but significantly less specific (95.2 vs. 100 %, p < 0.001). There was a trend towards greater accuracy in the diagnosis of subscapularis tears with 3-T MRA. Three-Tesla 3D isotropic MRA showed similar accuracy to 3-T conventional 2D MRA. Three-Tesla MRI appeared equivalent to 3-T MRA in the diagnosis of full- and partial-thickness tears, although there was a trend towards greater accuracy in the diagnosis of subscapularis tears with 3-T MRA. Three-Tesla 3D isotropic MRA appears equivalent to 3-T 2D MRA for all types of tears. (orig.)

  10. Fetal abdominal magnetic resonance imaging

    This review deals with the in vivo magnetic resonance imaging (MRI) appearance of the human fetal abdomen. Imaging findings are correlated with current knowledge of human fetal anatomy and physiology, which are crucial to understand and interpret fetal abdominal MRI scans. As fetal MRI covers a period of more than 20 weeks, which is characterized not only by organ growth, but also by changes and maturation of organ function, a different MR appearance of the fetal abdomen results. This not only applies to the fetal intestines, but also to the fetal liver, spleen, and adrenal glands. Choosing the appropriate sequences, various aspects of age-related and organ-specific function can be visualized with fetal MRI, as these are mirrored by changes in signal intensities. Knowledge of normal development is essential to delineate normal from pathological findings in the respective developmental stages

  11. Magnetic Resonance Imaging of Electrolysis.

    Meir, Arie; Hjouj, Mohammad; Rubinsky, Liel; Rubinsky, Boris

    2015-02-01

    This study explores the hypothesis that Magnetic Resonance Imaging (MRI) can image the process of electrolysis by detecting pH fronts. The study has relevance to real time control of cell ablation with electrolysis. To investigate the hypothesis we compare the following MR imaging sequences: T1 weighted, T2 weighted and Proton Density (PD), with optical images acquired using pH-sensitive dyes embedded in a physiological saline agar solution phantom treated with electrolysis and discrete measurements with a pH microprobe. We further demonstrate the biological relevance of our work using a bacterial E. Coli model, grown on the phantom. The results demonstrate the ability of MRI to image electrolysis produced pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E. Coli model grown on the phantom. The results are promising and invite further experimental research.

  12. Magnetic Resonance Imaging of Neurosarcoidosis

    Daniel T Ginat

    2011-01-01

    Full Text Available Neurosarcoidosis is an uncommon condition with protean manifestations. Magnetic resonance imaging (MRI is often used in the diagnostic evaluation and follow-up of patients with neurosarcoidosis. Therefore, familiarity with the variety of MRI appearances is important. In this pictorial essay, the range of possible patterns of involvement in neurosarcoidosis are depicted and discussed. These include intracranial and spine leptomeningeal involvement, cortical and cerebral white matter lesions, corpus callosum involvement, sellar and suprasellar involvement, periventricular involvement, cranial nerve involvement, cavernous sinus involvement, hydrocephalus, dural involvement, ischemic lesions, perivascular involvement, orbit lesions, osseous involvement, nerve root involvement, and spinal cord intramedullary involvement. Differential diagnoses for each pattern of involvement of neurosarcoidosis are also provided.

  13. Synovial pathology: Magnetic resonance study

    The synovial membrane lines the inner surface of the entire joint capsule of the so-called synovial, or diarthrosis, joints. It also constitutes the lining synovial bursa and tendon sheaths. It is lubricated at all these sites by the synovial fluid secreted by the membrane itself. The identification of this structure is bases on the correct knowledge of its anatomical locations. Synovial membrane pathology includes lesions produced by tumors, inflammation, degeneration and trauma. In this report, we classify them as benign (cysts, chondromatosis, pigmented villonodular synovitis, inflammatory synovitis and hemangioma) or malignant (synovial sarcoma and hemangiosarcoma). Magnetic resonance (MR) constitutes a useful and reliable method for diagnosis synovial lesions, providing a means of determining their origin and identifying distinctive features of some types. We present our experience in 12 cases of synovial pathology studied by MR over the past year, all of which were confirmed by histopathological study. 13 refs

  14. Fetal abdominal magnetic resonance imaging

    Brugger, Peter C. [Center of Anatomy and Cell Biology, Integrative Morphology Group, Medical University of Vienna, Waehringerstrasse 13, 1090 Vienna (Austria)]. E-mail: peter.brugger@meduniwien.ac.at; Prayer, Daniela [Department of Radiology, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna (Austria)

    2006-02-15

    This review deals with the in vivo magnetic resonance imaging (MRI) appearance of the human fetal abdomen. Imaging findings are correlated with current knowledge of human fetal anatomy and physiology, which are crucial to understand and interpret fetal abdominal MRI scans. As fetal MRI covers a period of more than 20 weeks, which is characterized not only by organ growth, but also by changes and maturation of organ function, a different MR appearance of the fetal abdomen results. This not only applies to the fetal intestines, but also to the fetal liver, spleen, and adrenal glands. Choosing the appropriate sequences, various aspects of age-related and organ-specific function can be visualized with fetal MRI, as these are mirrored by changes in signal intensities. Knowledge of normal development is essential to delineate normal from pathological findings in the respective developmental stages.

  15. Contrast agents in magnetic resonance imaging

    The origine of nuclear magnetic resonance signal is reminded and different ways for contrast enhancement in magnetic resonance imaging are presented, especially, modifications of tissus relaxation times. Investigations have focused on development of agents incorporating either paramagnetic ions or stable free radicals. Pharmacological and toxicological aspects are developed. The diagnostic potential of these substances is illustrated by the example of gadolinium complexes

  16. Pituitary tumors: Diagnosis by magnetic resonance imaging

    This paper presents a survey of the current status of the diagnosis of pituitary tumors by means of magnetic resonance imaging. It focuses on the clinical and practical aspects. The recommended procedure and the sequences and slice orientations for magnetic resonance imaging of the pituitary gland are presented, and the features that are essential for the diagnosis of pituitary tumors are discussed. (orig.)

  17. Magnetic resonance force microscopy: recent results

    Force detection of magnetic resonance has been demonstrated experimentally and used for imaging in EPR. This paper will review the basic principles of Magnetic Resonance Force Microscopy (MRFM) and will report some recent results in NMR imaging and the operation of a low-temperature MRFM. (author). 31 refs., 14 figs

  18. Nuclear magnetic resonance studies of erythrocyte membranes

    Chapman, D.; Kamat, V.B.; Gier, J. de; Penkett, S.A.

    1968-01-01

    The use of nuclear magnetic resonance spectroscopy for studying molecular interactions in biological membranes has been investigated using erythrocyte membrane fragments. Sonic dispersion of these fragments produces a sharp and well-defined high-resolution nuclear magnetic resonance spectrum. The sp

  19. Chemical Principles Revisited. Proton Magnetic Resonance Spectroscopy.

    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)

  20. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Full Text Available ... produced by: Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA ...

  1. Magnetic resonance imaging of the prostate

    Iversen, P; Kjaer, L; Thomsen, C;

    1987-01-01

    Magnetic resonance imaging offers new possibilities in the investigation of the prostate. The current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be of value in the staging of carcinoma of the prostate....

  2. Magnetic resonance imaging of the prostate

    Iversen, P; Kjaer, L; Thomsen, C;

    1988-01-01

    Magnetic resonance imaging offers new possibilities in investigation of the prostate gland. Current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be useful in the staging of carcinoma of the prostate....

  3. Functional Magnetic Resonance Imaging and Pediatric Anxiety

    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.…

  4. Pocket atlas of sectional anatomy: computed tomography and magnetic resonance imaging. Vol. 3. Spine, extremities, joints

    Moeller, T.B.; Reif, E. [Caritas Hospital, Dillingen (Germany). Dept. of Radiology

    2007-07-01

    Magnetic resonance imaging (MRI) of the musculoskeletal system is an established and important component in the diagnosis of diseases of the joints, soft tissues, bones, and bone marrow. We are therefore pleased to collect together images of the joints and the spinal column in a separate volume on the musculoskeletal system. Demonstrating the growing importance of new developments in MRI in recent years, with ever-increasing resolution, many images were acquired with 3-tesla units. We are deeply grateful to the manufacturers, Siemens and Philips, for making this possible. We believe that colored atlases are the ideal medium to represent the highly detailed images achieved nowadays with improved resolution techniques. Volume 3 of the Pocket Atlas of Sectional Anatomay provides a color illustration facing each magnetic resonance image, as in the preceding volumes on the skull, thorax, and abdomen. To ensure the greatest possible precision in details, we still produce these illustrations ourselves. Each is accompanied by a sectional image and an orientation aid. Uniform color schemes ensure optimal clarity, as similar structures, such as arteries, veins, nerves, tendons, etc., are consistently represented in the same color. Individual muscle groups are represented uniformly, but differentiated from other muscle groups, so that classification is possible even when numerous groups of muscles are shown in the same image. Maximal lucidity prevails even in highly detailed representations. This is made possible by the high quality of the production and printing process that are characteristic of Thieme International. (orig.)

  5. Magnetic non-collinear neutron wave resonator

    Khaidukov, Yu N

    2009-01-01

    The expression are received for amplitude of neutron reflection from layered magnetic non-collinear structure (neutron wave resonator (NWR)). It is showed the magnetic non-collinear NWR is characterized by the system of pairs of resonances for the spin flipped neutrons. The conditions are defined at which amplifying of spin-flipped neutron flux in wave resonator is multiple increased in comparison with amplifying of neutron absorption.

  6. Magnetic Resonance of the Knee

    Magnetic Resonance Imaging (MRI) has been applied to muscoloskeletal pathoanatomy and has proved to be useful in the detection and characterization of knees and 8 normal knees were examined. The images were obtained in the Diagnostic Centre RMRC of Naples on a 0.5 T superconductive magnetic system, using a surface coil and a spin-echo pulse sequence (SE 600/28 ms). The examined limb was immobilized and bent at 8-10 grade, extrarotated for the examination of the anterior cruciate ligament (ACL) only. Images were obtained on a 256x256 matrix and had a 2 or 4-mm thickness. MRI cleary showed all the anatomical structures. The anterior and posterior cruciate ligaments (ACL and PAL) and tha patellar ligament were shown by sagittal SE images through the intercondylar notch; the tibial and fibular collateral ligaments (TCL and FCL) were evaluated on coronal SE images; the articular capsula and menisci on axial transverse SE images. Objective criteria for ACL and PCL tears were: lack of continuity of the signal and change in signal intensity; in meniscal pathology, menisci with small linear regions of increased signal or with grossly truncated shape were interpreted as tears. Preliminary results of this study indicate that MRI together with clinical evaluation may be an useful non-invasive procedure in the assessment of acute injuries of the knee

  7. Stepped Impedance Resonators for High Field Magnetic Resonance Imaging

    Akgun, Can E.; DelaBarre, Lance; Yoo, Hyoungsuk; Sohn, Sung-Min; Snyder, Carl J.; Adriany, Gregor; Ugurbil, Kamil; Gopinath, Anand; Vaughan, J. Thomas

    2014-01-01

    Multi-element volume radio-frequency (RF) coils are an integral aspect of the growing field of high field magnetic resonance imaging (MRI). In these systems, a popular volume coil of choice has become the transverse electromagnetic (TEM) multi-element transceiver coil consisting of microstrip resonators. In this paper, to further advance this design approach, a new microstrip resonator strategy in which the transmission line is segmented into alternating impedance sections referred to as step...

  8. Magnetic Microparticle Aggregation For Viscosity Determination By Magnetic Resonance

    Hong, Rui; Cima, Michael J; Weissleder, Ralph; Josephson, Lee

    2008-01-01

    Micron-sized magnetic particles were induced to aggregate when placed in homogeneous magnetic fields, like those of magnetic resonance (MR) imagers and relaxometers, and then spontaneously returned to their dispersed state when removed from the field. Associated with the aggregation and dispersion of the magnetic particles were time dependent increases and decreases in the spin-spin relaxation time (T2) of the water. Magnetic nanoparticles, with far smaller magnetic moments per particle, did ...

  9. Nuclear Magnetic Resonance imaging; Resonance magnetique nucleaire

    Thibierge, M.; Sevestre, L.; Slupecki, P. [Centre Hospitalier de Charleville-Mezieres, 08 (France)

    1998-06-01

    After many years of low profile business in the USA, MRI is back. Improvements are focused on high field magnets and on low field magnets. The former, are dedicated to high quality imaging. The new scanners are more and more efficient because of the spreading use of real time imaging. They can do now, procedures that just could not be imagined some years ago. Vascular imaging is done routinely. Abdominal imaging in apnea of EPI, perfusion and diffusion imaging, and, last not least, all the field of functional imaging are on the verge of coming out. The new magnets unveiled in 1997 are lighter, smaller, more, user friendly, less impressive for patients subject to claustrophobia. They also need less helium to operate and less space to be sited. The latter, are dedicated to interventional procedures. The new magnets are wide opened and a lot of companies show off. Though Picker unveiled a new light superconductive 0.5 Tesla magnet, it seems that this kind of machines are about to disappear. No significant progress was noticed in the field of dedicated MRI devices. Some features can be highlighted: the new Siemens short bore and its table integrates the Panoramic Array Coil Concept. It will allow simultaneous scanning with up to four coils; the excellent homogeneity of the new Picker magnet that will allow spectroscopy at 1 Tesla; the twin gradients of the Elscint Prisma that will open the field of microscopy MRI; the Philips `floppy gradients` that could speed up 4 or 6 times, the time needed for imaging; some new sequences sensitive to temperature are studied as WIP; a lot of work is achieved on 3 or 4 Tesla scanners etc. (author)

  10. Noninvasive measurements of regional cerebral perfusion in preterm and term neonates by magnetic resonance arterial spin labeling

    Miranda Gimenez-Ricco, Maria Jo; Olofsson, K; Sidaros, Karam

    2006-01-01

    Magnetic resonance arterial spin labeling (ASL) at 3 Tesla has been investigated as a quantitative technique for measuring regional cerebral perfusion (RCP) in newborn infants. RCP values were measured in 49 healthy neonates: 32 preterm infants born before 34 wk of gestation and 17 term...... higher (p < 0.0001) than in cortical gray matter (19 and 16 mL/100 g/min) and white matter (15 and 10 mL/100 g/min), both in preterm neonates at term-equivalent age and in term neonates. Perfusion was significantly higher (p = 0.01) in the preterm group than in the term infants, indicating that RCP may...... be influenced by developmental and postnatal ages. This study demonstrates, for the first time, that noninvasive ASL at 3T may be used to measure RCP in healthy unsedated preterm and term neonates. ASL is, therefore, a viable tool that will allow serial studies of RCP in high-risk neonates...

  11. Evaluation of slice accelerations using multiband echo planar imaging at 3 Tesla

    Xu, Junqian; Moeller, Steen; Auerbach, Edward J.; Strupp, John; Stephen M Smith; Feinberg, David A.; Yacoub, Essa; Uğurbil, Kâmil

    2013-01-01

    We evaluate residual aliasing among simultaneously excited and acquired slices in slice accelerated multiband (MB) echo planar imaging (EPI). No in-plane accelerations were used in order to maximize and evaluate achievable slice acceleration factors at 3 Tesla. We propose a novel leakage (L-) factor to quantify the effects of signal leakage between simultaneously acquired slices. With a standard 32-channel receiver coil at 3 Tesla, we demonstrate that slice acceleration factors of up to eight...

  12. Magnetic resonance imaging in mucopolysaccharidosis

    Nakajima, Seijun; Tanaka, Akemi; Kawawaki, Hisashi; Hattori, Hideji; Matsuoka, Osamu; Murata, Ryosuke; Isshiki, Gen; Inoue, Yuichi

    1988-11-01

    Magnetic resonance (MR) images in six patients with mucopolysaccharidosis (MPS), two with type I S, one with type II A, two with type III B, and one with type VI MPS, were reviewed and compared with reported pathological findings and with CT scans. We used a Picker International MR imager with a 0.5-tesla superconducting magnet. The pulse sequences involved the inversion recovery technique (TR, 2,100 msec ; TI, 600 msec ; TE, 40 msec) for the T/sub 1/-weighted images and spin echo technique (TR, 1,800 msec ; TE, 120 msec) for the T/sub 2/-weighted images. The TC scanner was a Somatom 2 or DR3. In the patients with type II A and type VI MPS, there were multi-focal lesions of various sizes that showed prolonged T/sub 1/ and T/sub 2/ in the white matter. These lesions, which were not detected by CT, seemed to be correlated with the pathological findings of cavitation and dilated periadventitial space with viscous fluid. In the patients with type II A and type III B MPS, the T/sub 2/-weighted images showed a reduced contrast between gray and white matters, which may be related to the deposition of glycolipids and mucopolysaccharides in the lysosomes of the neurons and astrocytes of the gray and white matters. These findings seemed to be correlated with the clinical finding of mental retardation. In the patient of type II A MPS, there were lesions that showed prolonged T/sub 2/ of the periventricular white matter, suggesting periventricular edema. But CT hardly detected these lesions. In the patients with type I S MPS, no abnormal findings were found in MR imaging. It was concluded that MR imaging was far more sensitive for the detection of MPS lesions than CT, and was a useful method for differential diagnosis in MPS.

  13. Magnetic resonance imaging in mucopolysaccharidosis

    Magnetic resonance (MR) images in six patients with mucopolysaccharidosis (MPS), two with type I S, one with type II A, two with type III B, and one with type VI MPS, were reviewed and compared with reported pathological findings and with CT scans. We used a Picker International MR imager with a 0.5-tesla superconducting magnet. The pulse sequences involved the inversion recovery technique (TR, 2,100 msec ; TI, 600 msec ; TE, 40 msec) for the T1-weighted images and spin echo technique (TR, 1,800 msec ; TE, 120 msec) for the T2-weighted images. The TC scanner was a Somatom 2 or DR3. In the patients with type II A and type VI MPS, there were multi-focal lesions of various sizes that showed prolonged T1 and T2 in the white matter. These lesions, which were not detected by CT, seemed to be correlated with the pathological findings of cavitation and dilated periadventitial space with viscous fluid. In the patients with type II A and type III B MPS, the T2-weighted images showed a reduced contrast between gray and white matters, which may be related to the deposition of glycolipids and mucopolysaccharides in the lysosomes of the neurons and astrocytes of the gray and white matters. These findings seemed to be correlated with the clinical finding of mental retardation. In the patient of type II A MPS, there were lesions that showed prolonged T2 of the periventricular white matter, suggesting periventricular edema. But CT hardly detected these lesions. In the patients with type I S MPS, no abnormal findings were found in MR imaging. It was concluded that MR imaging was far more sensitive for the detection of MPS lesions than CT, and was a useful method for differential diagnosis in MPS. (author)

  14. Artifacts in Magnetic Resonance Imaging

    Artifacts in magnetic resonance imaging and foreign bodies within the patient’s body may be confused with a pathology or may reduce the quality of examinations. Radiologists are frequently not informed about the medical history of patients and face postoperative/other images they are not familiar with. A gallery of such images was presented in this manuscript. A truncation artifact in the spinal cord could be misinterpreted as a syrinx. Motion artifacts caused by breathing, cardiac movement, CSF pulsation/blood flow create a ghost artifact which can be reduced by patient immobilization, or cardiac/respiratory gating. Aliasing artifacts can be eliminated by increasing the field of view. An artificially hyperintense signal on FLAIR images can result from magnetic susceptibility artifacts, CSF/vascular pulsation, motion, but can also be found in patients undergoing MRI examinations while receiving supplemental oxygen. Metallic and other foreign bodies which may be found on and in patients’ bodies are the main group of artifacts and these are the focus of this study: e.g. make-up, tattoos, hairbands, clothes, endovascular embolization, prostheses, surgical clips, intraorbital and other medical implants, etc. Knowledge of different types of artifacts and their origin, and of possible foreign bodies is necessary to eliminate them or to reduce their negative influence on MR images by adjusting acquisition parameters. It is also necessary to take them into consideration when interpreting the images. Some proposals of reducing artifacts have been mentioned. Describing in detail the procedures to avoid or limit the artifacts would go beyond the scope of this paper but technical ways to reduce them can be found in the cited literature

  15. Interaction of magnetic resonators studied by the magnetic field enhancement

    Yumin Hou

    2013-01-01

    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 osci...

  16. Functional magnetic resonance imaging by visual stimulation

    We evaluated functional magnetic resonance images obtained in 8 healthy subjects in response to visual stimulation using a conventional clinical magnetic resonance imaging system with multi-slice spin-echo echo planar imaging. Activation in the visual cortex was clearly demonstrated by the multi-slice experiment with a task-related change in signal intensity. In addition to the primary visual cortex, other areas were also activated by a complicated visual task. Multi-slice spin-echo echo planar imaging offers high temporal resolution and allows the three-dimensional analysis of brain function. Functional magnetic resonance imaging provides a useful noninvasive method of mapping brain function. (author)

  17. Presurgical functional magnetic resonance imaging

    Functional magnetic resonance imaging (fMRI) is an important and novel neuroimaging modality for patients with brain tumors. By non-invasive measurement, localization and lateralization of brain activiation, most importantly of motor and speech function, fMRI facilitates the selection of the most appropriate and sparing treatment and function-preserving surgery. Prerequisites for the diagnostic use of fMRI are the application of dedicated clinical imaging protocols and standardization of the respective imaging procedures. The combination with diffusion tensor imaging (DTI) also enables tracking and visualization of important fiber bundles such as the pyramidal tract and the arcuate fascicle. These multimodal MR data can be implemented in computer systems for functional neuronavigation or radiation treatment. The practicability, accuracy and reliability of presurgical fMRI have been validated by large numbers of published data. However, fMRI cannot be considered as a fully established modality of diagnostic neuroimaging due to the lack of guidelines of the responsible medical associations as well as the lack of medical certification of important hardware and software components. This article reviews the current research in the field and provides practical information relevant for presurgical fMRI. (orig.)

  18. Magnetic resonance in multiple sclerosis

    Magnetic Resonance Imaging was performed in more than 200 patients with clinical suspicion or knowledge of Multiple Sclerosis. One hundred and forty-seven (60 males and 87 females) had MR evidence of multiple sclerosis lesions. The MR signal of demyelinating plaques characteristically has prolonged T1 and T2 relaxation times and the T2-weighted spin-echo sequences are generally superior to the T1-weighted images because the lesions are better visualized as areas of increased signal intensity. MR is also able to detect plaques in the brainstem, cerebellum and within the cervical spinal cord. MR appears to be an important, non-invasive method for the diagnosis of Multiple Sclerosis and has proven to be diagnostically superior to CT, evoked potentials (EP) and CSF examination. In a selected group of 30 patients, with the whole battery of the relevant MS studies, MR was positive in 100%, CT in 33,3%, EP in 56% and CSF examination in 60%. In patients clinically presenting only with signs of spinal cord involvement or optic neuritis or when the clinical presentation is uncertain MR has proven to be a very useful diagnostic tool for diagnosis of MS by demonstrating unsuspected lesions in the cerebral hemispheres. (orig.)

  19. Quantitative assessment of right ventricular function and pulmonary regurgitation in surgically repaired tetralogy of Fallot using 256-slice CT: comparison with 3-Tesla MRI

    Yamasaki, Yuzo; Yonezawa, Masato; Matsuo, Yoshio; Kamitani, Takeshi; Higuchi, Ko; Honda, Hiroshi [Graduate School of Medical Sciences, Kyushu University, Department of Clinical Radiology, Higashi-ku, Fukuoka (Japan); Nagao, Michinobu; Kawanami, Satoshi [Graduate School of Medical Sciences, Kyushu University, Department of Molecular Imaging and Diagnosis, Higashi-ku, Fukuoka (Japan); Yamamura, Kenichiro [Graduate School of Medical Sciences, Kyushu University, Department of Pediatrics, Higashi-ku, Fukuoka (Japan); Sakamoto, Ichiro [Graduate School of Medical Sciences, Kyushu University, Department of Cardiovascular Medicine, Higashi-ku, Fukuoka (Japan); Shiokawa, Yuichi [Graduate School of Medical Sciences, Kyushu University, Department of Cardiovascular Surgery, Higashi-ku, Fukuoka (Japan); Yabuuchi, Hidetake [Graduate School of Medical Sciences, Kyushu University, Department of Health Sciences, Higashi-ku, Fukuoka (Japan)

    2014-12-15

    To compare 256-slice cardiac computed tomography (CCT) with cardiac magnetic resonance (CMR) imaging to assess right ventricular (RV) function and pulmonary regurgitant fraction (PRF) in patients with repaired tetralogy of Fallot (TOF). Thirty-three consecutive patients with repaired TOF underwent retrospective ECG-gated CCT and 3-Tesla CMR. RV and left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF) were measured using CCT and CMR. PRF-CCT (%) was defined as (RVSV - LVSV)/RVSV. PRF-CMR (%) was measured by the phase-contrast method. Repeated measurements were performed to determine intra- and interobserver variability. CCT measurements, including PRF, correlated highly with the CMR reference (r = 0.71-0.96). CCT overestimated RVEDV (mean difference, 17.1 ± 2.9 ml), RVESV (12.9 ± 2.1 ml) and RVSV (4.2 ± 2.0 ml), and underestimated RVEF (-2.6 ± 1.0 %) and PRF (-9.1 ± 2.0 %) compared with CMR. The limits of agreement between CCT and CMR were in a good range for all measurements. The variability in CCT measurements was lower than those in CMR. The estimated effective radiation dose was 7.6 ± 2.6 mSv. 256-slice CCT can assess RV function and PRF with relatively low dose radiation exposure in patients with repaired TOF, but overestimates RV volume and underestimates PRF. (orig.)

  20. HR 3 tesla MRI for the diagnosis of endolymphatic hydrops and differential diagnosis of inner ear tumors. Demonstrated by two cases with similar symptoms

    The synchronous appearance of different inner ear pathologies with a nearly equivalent clinical manifestation such as Meniere's disease and vestibular schwannoma is very rare but leads to a relevant dilemma concerning therapy options. MRI is the method of choice to detect intralabyrinthine tumors. Since endolymphatic hydrops is considered the morphological equivalent of Meniere's disease, magnetic resonance imaging including hT2w-FLAIR sequences 4 h after i.v. administration of gadolinium-based contrast agents (GBCA) allows the diagnosis and grading of endolymphatic hydrops in vivo synchronous to diagnosis and monitoring of ILT. To this day, only a few cases of intralabyrinthine schwannoma could be shown to appear simultaneously with endolymphatic hydrops by MRI, but to our knowledge the dedicated distinction of endolymphatic space has not been previously demonstrated. The aim of this work was not only to detect the coincidence of endolymphatic hydrops and vestibular schwannoma, but also to differentiate tumor tissue from endolymphatic space by 3 Tesla MRI. This enables therapy options that are originally indicated for Meniere's disease. The aim of this work was to describe the feasibility and usefulness of endolymphatic hydrops MRI on intralabyrinthal tumors in a special case of intravestibular schwannoma to demonstrate the high clinical relevance and impact in therapeutic decision-making for the synchronous appearance of endolymphatic hydrops and intralabyrinthine tumors. Therefore, we present a typical case of Meniere's disease in contrast to a patient with an intralabyrinthine schwannoma and Meniere's-like symptoms. (orig.)

  1. Quantitative assessment of right ventricular function and pulmonary regurgitation in surgically repaired tetralogy of Fallot using 256-slice CT: comparison with 3-Tesla MRI

    To compare 256-slice cardiac computed tomography (CCT) with cardiac magnetic resonance (CMR) imaging to assess right ventricular (RV) function and pulmonary regurgitant fraction (PRF) in patients with repaired tetralogy of Fallot (TOF). Thirty-three consecutive patients with repaired TOF underwent retrospective ECG-gated CCT and 3-Tesla CMR. RV and left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF) were measured using CCT and CMR. PRF-CCT (%) was defined as (RVSV - LVSV)/RVSV. PRF-CMR (%) was measured by the phase-contrast method. Repeated measurements were performed to determine intra- and interobserver variability. CCT measurements, including PRF, correlated highly with the CMR reference (r = 0.71-0.96). CCT overestimated RVEDV (mean difference, 17.1 ± 2.9 ml), RVESV (12.9 ± 2.1 ml) and RVSV (4.2 ± 2.0 ml), and underestimated RVEF (-2.6 ± 1.0 %) and PRF (-9.1 ± 2.0 %) compared with CMR. The limits of agreement between CCT and CMR were in a good range for all measurements. The variability in CCT measurements was lower than those in CMR. The estimated effective radiation dose was 7.6 ± 2.6 mSv. 256-slice CCT can assess RV function and PRF with relatively low dose radiation exposure in patients with repaired TOF, but overestimates RV volume and underestimates PRF. (orig.)

  2. A Magnetic Resonance Measurement Technique for Rapidly Switched Gradient Magnetic Fields in a Magnetic Resonance Tomograph

    K. Bartušek

    2003-01-01

    Full Text Available This paper describes a method for measuring of the gradient magnetic field in Nuclear Magnetic Resonance (NMR tomography, which is one of the modern medical diagnostic methods. A very important prerequisite for high quality imaging is a gradient magnetic field in the instrument with exactly defined properties. Nuclear magnetic resonance enables us to measure the pulse gradient magnetic field characteristics with high accuracy. These interesting precise methods were designed, realised, and tested at the Institute of Scientific Instruments (ISI of the Academy of Sciences of the Czech Republic. The first of them was the Instantaneous Frequency (IF method, which was developed into the Instantaneous Frequency of Spin Echo (IFSE and the Instantaneous Frequency of Spin Echo Series (IFSES methods. The above named methods are described in this paper and their a comparison is also presented.

  3. Enhancement of artificial magnetism via resonant bianisotropy

    Markovich, Dmitry; Baryshnikova, Kseniia; Shalin, Alexander; Samusev, Anton; Krasnok, Alexander; Belov, Pavel; Ginzburg, Pavel

    2016-03-01

    All-dielectric “magnetic light” nanophotonics based on high refractive index nanoparticles allows controlling magnetic component of light at nanoscale without having high dissipative losses. The artificial magnetic optical response of such nanoparticles originates from circular displacement currents excited inside those structures and strongly depends on geometry and dispersion of optical materials. Here an approach for enhancing of magnetic response via resonant bianisotropy effect is proposed and analyzed. The key mechanism of enhancement is based on electric-magnetic interaction between two electrically and magnetically resonant nanoparticles of all-dielectric dimer. It was shown that proper geometrical arrangement of the dimer in respect to the incident illumination direction allows flexible control over all vectorial components of the magnetic moment, tailoring the latter in the dynamical range of 100% and delivering enhancement up to 36% relative to performances of standalone spherical particles. The proposed approach provides pathways for designs of all-dielectric metamaterials and metasurfaces with strong magnetic responses.

  4. Reducing Field Distortion in Magnetic Resonance Imaging

    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

  5. Biliary Ascariasis on Magnetic Resonance Cholangiopancreatography

    Hashmi, Mohammad A; Jevan K De

    2009-01-01

    A 17-year-old girl presented with features of biliary obstruction. Magnetic resonance cholangi-pancreatography revealed typical linear signals in common bile duct, which appears like Ascaris lumbricoides. The diagnosis was confirmed by endoscopic removal of the worm.

  6. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Full Text Available ... this Site RadiologyInfo.org is produced by: Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) ... Recently posted: Focused Ultrasound for Uterine Fibroids Dementia Video: General Ultrasound Video: Pediatric Nuclear Medicine Radiology and ...

  7. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Full Text Available ... Pediatric Ultrasound Video: Angioplasty & vascular stenting Video: Arthrography Radiology and You About this Site RadiologyInfo.org is ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  8. Chronic liver disease: evaluation by magnetic resonance

    Magnetic resonance (MR) imaging distinguished hepatitis from fatty liver and cirrhosis in a woman with a history of alcohol abuse. Anatomic and physiologic manifestations of portal hypertension were also demonstrated by MR

  9. International Society for Magnetic Resonance in Medicine

    ... Join the ISMRM Journals History & Mission Central Office Society Award Winners Strategic Plan Policies Corporate Members Contact ... E-Library Virtual Meetings Connect With Us International Society for Magnetic Resonance in Medicine 2300 Clayton Road, ...

  10. Magnetic moment of the Roper resonance

    Bauer, T. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Gegelia, J., E-mail: gegelia@kph.uni-mainz.de [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, 44780 Bochum (Germany); High Energy Physics Institute of TSU, 0186 Tbilisi, Georgia (United States); Scherer, S. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany)

    2012-08-29

    The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.

  11. Magnetic resonance imaging for uterus leiomyoma diagnosis

    The possibilities of a new technique, magnetic resonance imaging (MRI) in leiomyoma diagnosis was studied. MRI has clear advantages to differentiate adenomyosis from lysosomes and to reveal combination of these processes, which can considerably influence the tactics of the treatment

  12. Magnetic moment of the Roper resonance

    Bauer, T.; Gegelia, J.; Scherer, S.

    2012-01-01

    The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.

  13. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Full Text Available ... Angioplasty & vascular stenting Video: Arthrography Video: Contrast Material Radiology and You Take our survey About this Site ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  14. Seeking tools for image fusion between computed tomography, structural and functional magnetic resonance methods for applications in neurosurgery; Ferramentas para fusao de imagens dos metodos de tomografia computadorizada, ressonancia magnetica e ressonancia magnetica funcional para aplicacao pre-neurocirurgica

    Rocha, Liana Guerra Sanches da, E-mail: liana@einstein.br [Departamento de Diagnostico por Imagem, Hospital Israelita Albert Einstein - HIAE, Sao Paulo (SP) (Brazil); Amaro Junior, Edson [Faculdade de Medicina, Universidade de Sao Paulo - USP, Sao Paulo, SP (Brazil). Deptartamento de Diagnostico por Imagem; Instituto do Cerebro - InCe, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil)

    2012-04-15

    To evaluate tools for the fusion of images generated by tomography and structural and functional magnetic resonance imaging. Methods: Magnetic resonance and functional magnetic resonance imaging were performed while a volunteer who had previously undergone cranial tomography performed motor and somatosensory tasks in a 3-Tesla scanner. Image data were analyzed with different programs, and the results were compared. Results: We constructed a flow chart of computational processes that allowed measurement of the spatial congruence between the methods. There was no single computational tool that contained the entire set of functions necessary to achieve the goal. Conclusion: The fusion of the images from the three methods proved to be feasible with the use of four free-access software programs (OsiriX, Register, MRIcro and FSL). Our results may serve as a basis for building software that will be useful as a virtual tool prior to neurosurgery. (author)

  15. Contribution to nuclear magnetic resonance imager using permanent magnets

    After some recalls of nuclear magnetic resonance, ways to get a stable and homogeneous magnetic field are studied with permanent magnets. Development of correction coils on integrated circuits has been particularly stressed. Gradient coil specific systems have been studied taking in account ferromagnetic material presence. Antenna system has been improved and possibility of image obtention with the prototype realized has been shown

  16. Nuclear Magnetic Resonance Imaging: Current Capabilities

    Davis, Peter L.; Crooks, Lawrence E.; Margulis, Alexander R.; Kaufman, Leon

    1982-01-01

    Nuclear magnetic resonance imaging can produce tomographic images of the body without ionizing radiation. Images of the head, chest, abdomen, pelvis and extremities have been obtained and normal structures and pathology have been identified. Soft tissue contrast with this method is superior to that with x-ray computerized tomography and its spatial resolution is approaching that of x-ray computerized tomography. In addition, nuclear magnetic resonance imaging enables us to image along the sag...

  17. Cardiovascular magnetic resonance of the right ventricle

    Alpendurada, Francisco Diogo

    2013-01-01

    Introduction: Whilst most of the attention has been devoted to the left ventricle in cardiovascular disease, the right ventricle has been somewhat neglected. In the last decades, there has been a renewal of interest in the right ventricle, in part driven by advances in cardiovascular imaging. Methods: Cardiovascular magnetic resonance is arguably the best imaging modality for the study of the right ventricle. In this research thesis, cardiovascular magnetic resonance w...

  18. Cat scratch disease: magnetic resonance imaging findings

    Cat scratch disease is an infectious lymphadenitis frequently occurring in children and adolescents. We present the magnetic resonance imaging findings of two patients with this disease. In both cases, lymphadenopathy was characterized by extensive stranding of the surrounding soft tissues, consistent with the inflammatory nature of this condition. Magnetic resonance imaging can be diagnostic and may obviate the need for invasive means of evaluation in patients suspected of having cat scratch disease. (orig.)

  19. Advanced magnetic resonance spectroscopy techniques and applications

    Cao, Peng; 曹鹏

    2013-01-01

    Magnetic resonance (MR) is a well-known non-invasive technique that provides spectra (by MR spectroscopy, MRS) and images (by magnetic resonance imaging, MRI) of the examined tissue with detailed metabolic, structural, and functional information. This doctoral work is focused on advanced methodologies and applications of MRS for probing cellular and molecular changes in vivo. A single-voxel diffusion-weighted (DW) MRS method was first developed for monitoring the size changes of intramyocellu...

  20. Concepts and indications of abdominal magnetic resonance

    A literature review and conceptualization was performed of the main indications of magnetic resonance studies of the abdomen and the characteristic findings for each sequence, according to organ and pathology. The radiologist has had in mind main indications for magnetic resonance studies of the abdomen, with the purpose to guide the clinician in the choice of imaging modality that works best for the patient at diagnosis

  1. Magnetic Resonance Imaging with a Dielectric Lens

    Vazquez, F.; Marrufo, O.; MARTIN,R; Rodriguez, A. O.

    2009-01-01

    Recently, metamaterials have been introduced to improve the signal-to-noise ratio (SNR) of magnetic resonance images with very promising results. However, the use polymers in the generation of high quality images in magnetic resonance imaging has not been fully been investigated. These investigations explored the use of a dielectric periodical array as a lens to improve the image SNR generated with single surface coils. Commercial polycarbonate glazing sheets were used together with a circula...

  2. Proton magnetic resonance spectroscopy in depression

    Naren P Rao; Venkatasubramanian, Ganesan; Bangalore N Gangadhar

    2011-01-01

    Magnetic Resonance Spectroscopy (MRS) is a unique technique that can directly assess the concentration of various biochemical metabolites in the brain. Thus, it is used in the study of molecular pathophysiology of different neuropsychiatric disorders, such as, the major depressive disorder and has been an area of active research. We conducted a computer-based literature search using the Pubmed database with ‘magnetic resonance spectroscopy’, ‘MRS’, ‘depression’, and ‘major depressive disorder...

  3. Can magnetic resonance imaging differentiate undifferentiated arthritis?

    Østergaard, Mikkel; Duer, Anne; Hørslev-Petersen, K

    2005-01-01

    A high sensitivity for the detection of inflammatory and destructive changes in inflammatory joint diseases makes magnetic resonance imaging potentially useful for assigning specific diagnoses, such as rheumatoid arthritis and psoriatic arthritis in arthritides, that remain undifferentiated after...... conventional clinical, biochemical and radiographic examinations. With recent data as the starting point, the present paper describes the current knowledge on magnetic resonance imaging in the differential diagnosis of undifferentiated arthritis....

  4. Magnetic resonance urography in children

    The imaging methods play an important role in the diagnosing of the urinary tract diseases in children. The magnetic resonance urography (MRU) aids the morphological and functional assessment of the urinary tract as well as the increase of the accuracy of the diagnosing process. Objective: The aim of the study is to assess the capabilities of the MRU for the diagnosing of the urogenital tract in children. Material and methods: In 30 children, age between 20 days and 14 years, suspected for urinary tract pathology MRU is performed. The technique includes a native and contrast examination of the abdomen and the pelvis. The duration, depending on the pathology, is between 20 and 30 min. The axial scans and the 3-dimensional reconstructed images have been processed at different reconstruction angle. The findings have been compared to the other imaging methods applied and the postoperative results. Results: The MRU has allowed to diagnose different types of urogenital diseases in children - 3 with double pyelo-calyx system, 12 with obstructed mega ureter, 5 with obstruction of the pyelo-urinary segment, 5 with accompanying parenchyma anomalies, 6 with renal calculi, 5 with tumors, 1 with extrarenal tumor formation, 3 with bladder anomalies and 1 with kidney transplantation. Most of the children have combined pathology. Conclusions: MRU shows significant advantages in a number of pathological conditions as urinary tract obstruction, renal tumors, transplanted kidney and some congenital anomalies. The technique is safe, non-invasive and relatively fast for children examinations. These features of MRU presents a reason to assume that it will replace a number of conventional radiography techniques, giving more precise diagnostic information

  5. Prostate cancer in magnetic resonance imaging: diagnostic utilites of spectroscopic sequences

    The aim of our work is to determine the efficacy of a combined study 3 Tesla Magnetic Resonance Imaging (3T MRI), with phased-array coil, for the detection of prostate cancer using magnetic resonance spectroscopy (MRS) and diffusion-weighted images (DWI) in identifying doubt nodules. In this study, we prospectively studied 46 patients who consecutively underwent digital-rectal exploration for high doses of prostate specific antigen (PSA), as well as a MRI examination and a subsequent rectal biopsy. The study of magnetic resonance imaging was performed with a Philips Achieva 3T scanner and phased-array coil. The images were obtained with turbo spin-echo sequences T2-weighted images, T1-weighted before and after the administration of contrast medium, DWI sequences and 3D spectroscopic sequences. The ultrasound-guided prostate biopsy was performed approximately 15 days after the MRI. The data obtained from MR images and spectroscopy were correlated with histological data. MRI revealed sensitivity and specificity of 88% and 61% respectively and positive predictive value (PPV) of 73%, negative predicted value (NPV) of 81% and accuracy of 76%. In identifying the location of prostate cancer, the sensitivity of 3T MRS was 92%, with a specificity of 89%, PPV of 87%, NPV of 88% and accuracy of 87%; DWI showed a sensitivity of 88%, specificity of 61%, PPV of 73%, NPV of 81% and accuracy of 76%. The 3T MR study with phased-array coil and the use of DWI and spectroscopic sequences, in addition to T2-weighted sequences, revealed to be accurate in the diagnosis of prostate cancer and in the identification of nodules to be biopsied. It may be indicated as a resolute way before biopsy in patients with elevated PSA value and can be proposed in the staging and follow-up.

  6. Complex Response Function of Magnetic Resonance Spectrometers

    Annino, G.; Cassettari, M.; Fittipaldi, M.; M. Martinelli

    2002-01-01

    A vectorial analysis of magnetic resonance spectrometers, based on traveling wave resonators and including the reference arm and the automatic control of frequency, has been developed. The proposed model, valid also for stationary wave resonators, gives the response function of the spectrometer for any working condition, including scalar detectors with arbitrary response law and arbitrary excitation frequency. The purely dispersive and purely absorptive linear responses are discussed in detai...

  7. Enhancement of artificial magnetism via resonant bianisotropy

    Markovich, Dmitry; Shalin, Alexander; Samusev, Anton; Krasnok, Alexander; Belov, Pavel; Ginzburg, Pavel

    2015-01-01

    All-dielectric "magnetic light" nanophotonics based on high refractive index nanoparticles allows controlling magnetic component of light at nanoscale without having high dissipative losses. The artificial magnetic optical response of such nanoparticles originates from circular displacement currents excited inside those structures and strongly depends on geometry and dispersion of optical materials. Here a new approach for increasing magnetic response via resonant bianisotropy effect is proposed and analyzed. The key mechanism of enhancement is based on electric-magnetic interaction between two electrically and magnetically resonant nanoparticles of all-dielectric dimer nanoantenna. It was shown that proper geometrical arrangement of the dimer in respect to the incident illumination direction allows flexible control over all vectorial components of magnetic polarizability, tailoring the later in the dynamical range of 100 % and enhancement up to 36 % relative to performances of standalone spherical particles....

  8. Nanoscale magnetic resonance imaging: Progress and challenges

    Magnetic resonance imaging (MRI), based on the sensitive detection of nuclear spins, enables three dimensional imaging without radiation damage. Conventional MRI techniques achieve spatial resolution that is at best a few micrometers due to sensitivity limitations of conventional inductive detection. The advent of ultrasensitive nanoscale magnetic sensing opens the possibility of extending MRI to the nanometer scale. If this can be pushed far enough, one can envision taking 3D images of individual biomolecules and, perhaps, even solving molecular structures of proteins. In this talk we will discuss issues related to nanoscale magnetic resonance imaging, especially its implementation using magnetic resonance force microscopy (MRFM). MRFM is based on the detection of ultrasmall (attonewton) magnetic forces. While 3D spatial resolution below 5 nm has been demonstrated, further progress depends on overcoming poorly understood near-surface force noise effects. We also consider the future possibility of using NV centers in diamond for detection of nanoMRI.

  9. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... of the head uses a powerful magnetic field, radio waves and a computer to produce detailed pictures ... medical conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed ...

  10. Magnetic Resonance Imaging (MRI) -- Head

    Full Text Available ... a powerful magnetic field, radio waves and a computer to produce detailed pictures of the brain and ... powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, ...