2024-03-29T07:37:19Z
http://eprints.drcmr.dk/cgi/oai2
oai:www.drcmr.dk:3
2010-04-02T00:05:17Z
7374617475733D707562
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7375626A656374733D4A3031:4A303178383937:4A30317838393778323830:4A3031783839377832383078353030:4A303178383937783238307835303078343830
74797065733D7465616368696E675F7265736F75726365
http://eprints.drcmr.dk/3/
Introduktion til teknikken bag MR-skanning
Hanson, Lars G.
Teaching
Magnetic Resonance Imaging
Medical Illustration
Magnetic Resonance Spectroscopy
Man kan optage billeder med en MR-skanner uden at forstå princippet bag, men det kræver forståelse at opsøge de rette parametre og målemetoder, og at fortolke billeder og artefakter. Teksten her udgør en introduktion til teknikken bag magnetisk resonans (MR) skanning. Dele er møntet på begyndere med et minimum af teknisk baggrund, mens andre dele sigter lidt højere. Dette afspejler, at noterne er skrevet i forbindelse med undervisning af personer med blandet baggrund.
DRCMR homepage
2004
Teaching Resource
NonPeerReviewed
application/pdf
http://eprints.drcmr.dk/3/1/Intro.pdf
http://www.drcmr.dk/Intro.pdf
Hanson, Lars G. (2004) Introduktion til teknikken bag MR-skanning. [Teaching Resource]
http://eprints.drcmr.dk/3/http://eprints.drcmr.dk/3/1/
oai:www.drcmr.dk:21
2010-04-02T08:24:07Z
7374617475733D707562
7375626A656374733D483031:48303178363731:4830317836373178373638:483031783637317837363878363338:48303178363731783736387836333878373231
7375626A656374733D483031:48303178363731:4830317836373178353739:483031783637317835373978363331
7375626A656374733D453031:45303178333730:4530317833373078333530:453031783337307833353078353030
74797065733D61727469636C65
http://eprints.drcmr.dk/21/
MR-skanning: Billeder fra den forbudte side af bølgelængdegrænsen
Hanson, Lars G.
Magnetic Resonance Imaging
Radio Waves
Magnetic Resonance Spectroscopy
Det er velkendt at almindelige optiske teknikker som mikroskopi og gennemlysning er bølgelængebegrænsede: På grund af lysets diffraktion ses ingen detaljer, der er mindre end bølgeængden af det anvendte lys. Ikke desto mindre er Magnetisk Resonans (MR) billeddannelse nu en udbredt skanningsmetode, der giver yderst detaljerede billeder af kroppens indre trods brug af bølgelængder i størrelsesorden meter. I 2002 blev en Nobelpris for klassisk MR billeddannelse givet til Paul Lauterbur og Sir Peter Mansfield. I de senere år har endnu en metode til at omgå bølgelængde-begrænsningen vundet stor indpas. Artiklen introducerer kernemagnetisk resonans (NMR) og de vigtigste billeddannelsesprincipper.
Niels Bohr Institute, University of Copenhagen
2006
Article
NonPeerReviewed
application/pdf
http://eprints.drcmr.dk/21/1/artikel.pdf
http://www.gamma.nbi.dk/
Hanson, Lars G. (2006) MR-skanning: Billeder fra den forbudte side af bølgelængdegrænsen. Gamma - tidsskrift for fysik (143). pp. 8-26. ISSN 0108-0954
http://eprints.drcmr.dk/21/http://eprints.drcmr.dk/21/1/
oai:www.drcmr.dk:22
2010-04-02T00:05:34Z
7374617475733D707562
7375626A656374733D493032:49303278393033:4930327839303378333032
7375626A656374733D483031:48303178363731:4830317836373178353739:483031783637317835373978363331
7375626A656374733D453031:45303178333730:4530317833373078333530:453031783337307833353078353030
7375626A656374733D4A3031:4A303178383937:4A30317838393778323830:4A3031783839377832383078353030:4A303178383937783238307835303078343830
74797065733D61727469636C65
http://eprints.drcmr.dk/22/
Is Quantum Mechanics necessary for understanding Magnetic Resonance?
Hanson, Lars G.
Models, Educational
Magnetic Resonance Imaging
Medical Illustration
Magnetic Resonance Spectroscopy
Educational material introducing magnetic resonance typically contains sections on the underlying principles. Unfortunately the explanations given are often unnecessarily complicated or even wrong. Magnetic resonance is often presented as a phenomenon that necessitates a quantum mechanical explanation whereas it really is a classical effect, i.e. a consequence of the common sense expressed in classical mechanics. This insight is not new, but there have been few attempts to challenge common misleading explanations, so authors and educators are inadvertently keeping myths alive. As a result, new students' first encounters with magnetic resonance are often obscured by explanations that make the subject difficult to understand. Typical problems are addressed and alternative intuitive
explanations are provided.
Wiley InterScience
2008-09-03
Article
PeerReviewed
application/pdf
http://eprints.drcmr.dk/22/1/article.pdf
image/jpeg
http://eprints.drcmr.dk/22/2/MagSpherical2crop.jpg
image/jpeg
http://eprints.drcmr.dk/22/3/MagPrecession2.jpg
image/jpeg
http://eprints.drcmr.dk/22/4/MagEquilib2.jpg
image/jpeg
http://eprints.drcmr.dk/22/5/MagRotated2.jpg
http://www3.interscience.wiley.com/journal/121394126/abstract
Hanson, Lars G. (2008) Is Quantum Mechanics necessary for understanding Magnetic Resonance? Concepts in Magnetic Resonance Part A, 32A (5). pp. 329-340. ISSN 1546-6086
http://eprints.drcmr.dk/22/http://eprints.drcmr.dk/22/1/http://eprints.drcmr.dk/22/2/http://eprints.drcmr.dk/22/3/http://eprints.drcmr.dk/22/4/http://eprints.drcmr.dk/22/5/
oai:www.drcmr.dk:25
2010-04-02T00:05:39Z
7374617475733D707562
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7375626A656374733D413038:41303878313836
7375626A656374733D473039:47303978333330
7375626A656374733D433130:43313078323238:4331307832323878313430
7375626A656374733D433130:43313078353734
7375626A656374733D483031:48303178363731
7375626A656374733D483031:48303178353438:4830317835343878363335
7375626A656374733D433130:43313078333134:4331307833313478333530:433130783331347833353078353030
7375626A656374733D483031:48303178373730
7375626A656374733D473031:47303178363130
74797065733D6F74686572
http://eprints.drcmr.dk/25/
DRCMR Annual Report 2007
Sidaros, K.
Science
Central Nervous System
Brain
Neurosciences
Multiple Sclerosis
Research
Physics
Cardiovascular Physiology
Neurodegenerative Diseases
Brain Diseases
Mathematical Computing
The 2007 annual report of the Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Denmark.
DRCMR
Other
NonPeerReviewed
application/pdf
http://eprints.drcmr.dk/25/1/Annual_report_2007_s.pdf
application/pdf
http://eprints.drcmr.dk/25/2/Annual_report_2007_p.pdf
image/jpeg
http://eprints.drcmr.dk/25/3/Annual_report_2007_icon.jpg
Sidaros, K. DRCMR Annual Report 2007. DRCMR.
http://eprints.drcmr.dk/25/http://eprints.drcmr.dk/25/1/http://eprints.drcmr.dk/25/2/http://eprints.drcmr.dk/25/3/
oai:www.drcmr.dk:28
2010-04-02T00:05:41Z
7374617475733D707562
7375626A656374733D493032:49303278393033
7375626A656374733D453031:45303178333730:4530317833373078333530:453031783337307833353078353030
7375626A656374733D483031:48303178363731:4830317836373178353739:483031783637317835373978363331
7375626A656374733D4A3031:4A303178383937:4A30317838393778323830:4A3031783839377832383078353030:4A303178383937783238307835303078343830
74797065733D7465616368696E675F7265736F75726365
http://eprints.drcmr.dk/28/
Introduktion til teknikken bag MR-skanning
Hanson, Lars G.
Teaching
Magnetic Resonance Imaging
Medical Illustration
Magnetic Resonance Spectroscopy
Man kan optage billeder med en MR-skanner uden at forstå princippet bag, men det kræver forståelse at opsøge de rette parametre og målemetoder, og at fortolke billeder og artefakter. Teksten her udgør en introduktion til teknikken bag magnetisk resonans (MR) skanning. Dele er møntet på begyndere med et minimum af teknisk baggrund, mens andre dele sigter lidt højere. Dette afspejler, at noterne er skrevet i forbindelse med undervisning af personer med blandet baggrund.
DRCMR homepage
2009-01-23
Teaching Resource
NonPeerReviewed
application/pdf
http://eprints.drcmr.dk/28/4/Intro.pdf
http://www.drcmr.dk/Intro.pdf
Hanson, Lars G. (2009) Introduktion til teknikken bag MR-skanning. [Teaching Resource]
http://eprints.drcmr.dk/28/http://eprints.drcmr.dk/28/4/
oai:www.drcmr.dk:33
2010-04-02T08:42:07Z
7374617475733D707562
7375626A656374733D493032:49303278393033
7375626A656374733D453031:45303178333730:4530317833373078333530:453031783337307833353078353030
7375626A656374733D483031:48303178363731:4830317836373178353739:483031783637317835373978363331
7375626A656374733D4A3031:4A303178383937:4A30317838393778323830:4A3031783839377832383078353030:4A303178383937783238307835303078343830
74797065733D7465616368696E675F7265736F75726365
http://eprints.drcmr.dk/33/
Introduktion til teknikken bag MR-skanning
Hanson, Lars G.
Teaching
Magnetic Resonance Imaging
Medical Illustration
Magnetic Resonance Spectroscopy
Man kan optage billeder med en MR-skanner uden at forstå princippet bag, men det kræver forståelse at opsøge de rette parametre og målemetoder, og at fortolke billeder og artefakter. Teksten her udgør en introduktion til teknikken bag magnetisk resonans (MR) skanning. Dele er møntet på begyndere med et minimum af teknisk baggrund, mens andre dele sigter højere. Dette afspejler, at noterne er skrevet i forbindelse med undervisning af personer med blandet baggrund.
DRCMR homepage
2009-05-26
Teaching Resource
NonPeerReviewed
application/pdf
http://eprints.drcmr.dk/33/3/Intro.pdf
http://www.drcmr.dk/Intro.pdf
Hanson, Lars G. (2009) Introduktion til teknikken bag MR-skanning. [Teaching Resource]
http://eprints.drcmr.dk/33/http://eprints.drcmr.dk/33/3/
oai:www.drcmr.dk:36
2010-04-02T00:05:48Z
7374617475733D707562
7375626A656374733D413038:41303878313836:4130387831383678323131
7375626A656374733D483031:48303178373730:4830317837373078363434
7375626A656374733D433130:43313078323238:4331307832323878313430
7375626A656374733D433130:43313078353734
7375626A656374733D433130:43313078393030
7375626A656374733D413038:41303878313836
7375626A656374733D483031:48303178353438:4830317835343878363335
7375626A656374733D483031:48303178363731
7375626A656374733D433130:43313078333134:4331307833313478333530:433130783331347833353078353030
7375626A656374733D473031:47303178363130
7375626A656374733D483031:48303178373730
74797065733D6F74686572
http://eprints.drcmr.dk/36/
DRCMR Annual Report 2008
DRCMR,
Science
Central Nervous System
Brain
Trauma, Nervous System
Neurosciences
Multiple Sclerosis
Research
Physics
Neurodegenerative Diseases
Brain Diseases
Mathematical Computing
The 2008 annual report of the Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Denmark.
DRCMR
Other
NonPeerReviewed
image/jpeg
http://eprints.drcmr.dk/36/1/Annual_report_2008_icon.jpg
application/pdf
http://eprints.drcmr.dk/36/2/Annual_report_2008_s.pdf
application/pdf
http://eprints.drcmr.dk/36/3/Annual_report_2008_p.pdf
DRCMR, DRCMR Annual Report 2008. DRCMR.
http://eprints.drcmr.dk/36/http://eprints.drcmr.dk/36/1/http://eprints.drcmr.dk/36/2/http://eprints.drcmr.dk/36/3/
oai:www.drcmr.dk:37
2010-04-02T00:05:51Z
7374617475733D707562
7375626A656374733D493032:49303278393033
7375626A656374733D483031:48303178363731:4830317836373178353739:483031783637317835373978363331
7375626A656374733D453031:45303178333730:4530317833373078333530:453031783337307833353078353030
7375626A656374733D4A3031:4A303178383937:4A30317838393778323830:4A3031783839377832383078353030:4A303178383937783238307835303078343830
74797065733D7465616368696E675F7265736F75726365
http://eprints.drcmr.dk/37/
Introduction to Magnetic Resonance Imaging Techniques
Hanson, Lars G.
Teaching
Magnetic Resonance Imaging
Medical Illustration
Magnetic Resonance Spectroscopy
It is quite possible to acquire images with an MR scanner without understanding the principles behind it, but choosing the best parameters and methods, and interpreting images and artifacts, requires understanding. This text serves as an introduction to magnetic resonance imaging techniques. It is aimed at beginners in possession of only a minimal level of technical expertise, yet it introduces aspects of MR that are typically considered technically challenging. The notes were written in connection with teaching of audiences with mixed backgrounds.
2009-08-31
Teaching Resource
NonPeerReviewed
application/pdf
http://eprints.drcmr.dk/37/1/MRI_English_a4.pdf
application/pdf
http://eprints.drcmr.dk/37/2/MRI_English_letter.pdf
Hanson, Lars G. (2009) Introduction to Magnetic Resonance Imaging Techniques. [Teaching Resource]
http://eprints.drcmr.dk/37/http://eprints.drcmr.dk/37/1/http://eprints.drcmr.dk/37/2/
oai:www.drcmr.dk:40
2010-04-02T00:05:55Z
7374617475733D707562
7375626A656374733D483031:48303178363731:4830317836373178353739:483031783637317835373978363331
7375626A656374733D453031:45303178333730
7375626A656374733D453035:45303578313936:4530357831393678383637:453035783139367838363778353139
7375626A656374733D4D3031:4D303178303630:4D30317830363078373033:4D3031783036307837303378353230
74797065733D61727469636C65
http://eprints.drcmr.dk/40/
Motion correction of Single Voxel Spectroscopy by Independent Component Analysis applied to spectra from non-anesthetized pediatric subjects
de Nijs, Robin
Miranda, Maria J.
Hansen, Lars K
Hanson, Lars G.
Magnetic Resonance Spectroscopy
Infant, Newborn
Diagnostic Techniques and Procedures
Magnetic Resonance Spectroscopy
For Single Voxel Spectroscopy (SVS), the acquisition of the spectrum is typically repeated n times and then combined with a factor in order to improve the Signal-to-Noise Ratio (SNR). In practice the acquisitions are not only affected by random noise, but also by physiological motion and subject movements. Since the influence of physiological motion such as cardiac and respiratory motion on the data is limited, it can be compensated for without data-loss. Individual acquisitions hampered by subject movements on the other hand need to be rejected, if no correction or compensation is possible. If the individual acquisitions are stored, it is possible to identify and reject the motion-disturbed acquisitions before averaging.
Several automatic algorithms were investigated using a dataset of spectra from non-anesthetized infants with a gestational age of 40 weeks. Median filtering removed most subject movement artifacts, but at the cost of increased sensitivity to random noise. Neither Independent Component Analysis (ICA) nor outlier identification with multiple comparisons has this problem. These two algorithms are novel in this context. The peak height values of the metabolites were increased compared to the mean of all acquisitions for both methods, although primarily for the ICA method.
Wiley InterScience
2009-09-24
Article
PeerReviewed
application/pdf
http://eprints.drcmr.dk/40/1/Motion_rejection_01112009.pdf
de Nijs, Robin and Miranda, Maria J. and Hansen, Lars K and Hanson, Lars G. (2009) Motion correction of Single Voxel Spectroscopy by Independent Component Analysis applied to spectra from non-anesthetized pediatric subjects. Magnetic Resonance in Medicine, 62 (5). pp. 1147-1154. ISSN 0740-3194
http://eprints.drcmr.dk/40/http://eprints.drcmr.dk/40/1/
oai:www.drcmr.dk:42
2010-12-02T11:47:36Z
7374617475733D756E707562
7375626A656374733D453035:45303578313936:4530357831393678383637:453035783139367838363778353139
7375626A656374733D4D3031:4D303178303630:4D30317830363078373033:4D3031783036307837303378353230
7375626A656374733D483031:48303178363731:4830317836373178353739:483031783637317835373978363331
7375626A656374733D453031:45303178333730
74797065733D746865736973
http://eprints.drcmr.dk/42/
Corrections in clinical Magnetic Resonance Spectroscopy and SPECT: Motion correction in MR spectroscopy, downscatter correction in SPECT
de Nijs, Robin
Diagnostic Techniques and Procedures
Magnetic Resonance Spectroscopy
Magnetic Resonance Spectroscopy
Infant, Newborn
The quality of medical scanner data is often compromised by several mechanisms. This can be caused by both the subject to be measured and the scanning principles themselves. In this PhD project the problem of subject motion was addressed for Single Voxel MR Spectroscopy in a cohort study of preterm infants. In Iodine-123 SPECT the problem of downscatter was addressed. This thesis is based on two papers. Paper I deals with the problem of motion in Single Voxel Spectroscopy. Two novel methods for the identification of outliers in the set of repeated measurements were implemented and compared to the known mean and median filtering. The data comes from non-anesthetized preterm infants, where motion during scanning is a common problem. Both the novel outlier identification and the independent component analysis (ICA) perform satisfactory and better than the common mean and median filtering. ICA performed best in the sense that it recovered most of the lost peak height in the spectra. The ICA motion correction algorithm described in paper I and in this thesis was applied to a quantitative analysis of the Single Voxel Spectroscopy data from the cohort study of preterm infants. This analysis revealed that differences between term and preterm infants are not to be found in the concentrations of Lactate (caused by inflammation or hypoxia-ischemia) and/or NAA (caused by hypoxia-ischemia) as hypothesized before the cohort study. Instead choline levels were decreased in the preterm infants, which might indicate a detrimental effect of the extra-uterine environment on brain development. Paper II describes a method to correct for downscatter in low count Iodine-123 SPECT with a broad energy window above the normal imaging window. Both spatial dependency and weight factors were measured. As expected, the implicitly assumed weight factor of one for energy windows with equal width is slightly too low, due the presence of a backscatter peak in the energy spectrum coming from high-energy photons. The effect on the contrast was tested in 10 subjects and revealed a 20% increase in the specific binding ratio of the striatum due to downscatter correction. This makes the difference between healthy subjects and patients more profound. Downscatter in Iodine-123 SPECT is not the only deteriorating mechanism. Normal scatter compromises the images quality as well. Since scatter correction of SPECT-images also can be performed by the subtraction of an energy window, a method was developed to perform scatter and downscatter correction simultaneously. A phantom study has been performed, where the in paper II described downscatter correction was extended with scatter correction. This new combined correction was compared to the known Triple Energy Window (TEW) correction method. Results were satisfying and indicate that TEW is more correct from the physics point of view, while the in paper II described method extended with scatter correction gives reasonable results, but is far less noise sensitive than TEW.
2009-08
Thesis
NonPeerReviewed
application/pdf
http://eprints.drcmr.dk/42/1/phd221_rdn.pdf
de Nijs, Robin (2009) Corrections in clinical Magnetic Resonance Spectroscopy and SPECT: Motion correction in MR spectroscopy, downscatter correction in SPECT. PhD thesis, Technical University of Denmark.
http://eprints.drcmr.dk/42/http://eprints.drcmr.dk/42/1/
oai:www.drcmr.dk:43
2011-05-21T23:06:52Z
7374617475733D707562
7375626A656374733D483031:48303178363731:4830317836373178353739:483031783637317835373978363331
7375626A656374733D4A3031:4A303178383937:4A30317838393778323830:4A3031783839377832383078353030
7375626A656374733D493032:49303278393033:4930327839303378333032
74797065733D7465616368696E675F7265736F75726365
http://eprints.drcmr.dk/43/
Oplæg til gymnasie-øvelse i Magnetisk Resonans
Hanson, Lars G
Magnetic Resonance Spectroscopy
Models, Educational
Audiovisual Aids
Nærværende oplæg giver inspiration til et fysisk/kemisk gymnasie-forløb omhandlende magnetisk resonans (MR), som er et fænomen, der anvendes i medicinsk diagnostik og forskning (MR-skanning) og kemisk analyse (NMR-spektroskopi). Disse fascinerende metoder er baseret på brug af magnetisme, radiobølger, kernefysik og gyro-mekanik, men er grundlæggende ikke mere komplicerede end at de kan forstås intuitivt af elever med klassisk mekanisk intuition og et basalt kendskab til elektromagnetisme.
2011-04
Teaching Resource
NonPeerReviewed
application/msword
http://eprints.drcmr.dk/43/1/MagnetiskResonansVejledning.doc
http://www.drcmr.dk/JavaCompass
Hanson, Lars G (2011) Oplæg til gymnasie-øvelse i Magnetisk Resonans. [Teaching Resource]
http://eprints.drcmr.dk/43/http://eprints.drcmr.dk/43/1/
oai:www.drcmr.dk:44
2011-08-08T10:11:10Z
oai:www.drcmr.dk:45
2011-08-08T10:11:10Z
7374617475733D707562
7375626A656374733D473031:47303178363130
7375626A656374733D483031:48303178373730
7375626A656374733D483031:48303178353438:4830317835343878363335
7375626A656374733D433130:43313078333134:4331307833313478333530:433130783331347833353078353030
7375626A656374733D483031:48303178363731
7375626A656374733D433130:43313078393030
7375626A656374733D433130:43313078323238:4331307832323878313430
7375626A656374733D433130:43313078353734
7375626A656374733D413038:41303878313836
7375626A656374733D483031:48303178373730:4830317837373078363434
7375626A656374733D413038:41303878313836:4130387831383678323131
74797065733D6F74686572
http://eprints.drcmr.dk/45/
DRCMR Annual Report 2009-2010
DRCMR,
Science
Central Nervous System
Brain
Trauma, Nervous System
Neurosciences
Multiple Sclerosis
Research
Physics
Neurodegenerative Diseases
Brain Diseases
Mathematical Computing
The 2009-2010 annual report of the Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Denmark.
DRCMR
Other
NonPeerReviewed
image/jpeg
http://eprints.drcmr.dk/45/1/Annual_Report_2009%2D2010_icon.jpg
application/pdf
http://eprints.drcmr.dk/45/5/Annual_Report_2009%2D2010s.pdf
application/pdf
http://eprints.drcmr.dk/45/6/Annual_Report_2009%2D2010p.pdf
DRCMR, DRCMR Annual Report 2009-2010. DRCMR.
http://eprints.drcmr.dk/45/http://eprints.drcmr.dk/45/1/http://eprints.drcmr.dk/45/5/http://eprints.drcmr.dk/45/6/