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Giovannetti G, Guerrini A, Minozzi S, Panetta D, Salvadori PA. Computer tomography and magnetic resonance for multimodal imaging of fossils and mummies. Magn Reson Imaging 2022; 94:7-17. [PMID: 36084902 DOI: 10.1016/j.mri.2022.08.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/26/2022] [Accepted: 08/31/2022] [Indexed: 11/24/2022]
Abstract
The study of fossils and mummies has largely benefited from the use of modern noninvasive and nondestructive imaging technologies and represents a fast developing area. In this review, we describe the emerging role of imaging based on Magnetic Resonance (MR) and Computer Tomography (CT) employed for the study of ancient remains and mummies. For each methodology, the state of the art in paleoradiology applications is described, by emphasizing new technologies developed in the field of both CT, such as micro- and nano-CT, dual-energy and multi-energy CT, and MR, with the description of novel dedicated sequences, radiofrequency coils and gradients. The complementarity of CT and MR in paleoradiology is also discussed, by pointing out what MR provides in addition to CT, with an overview on the state of the art of emerging strategies in the use of CT/MR combination for the study of a sample following a multimodal integrated approach.
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Affiliation(s)
- Giulio Giovannetti
- Institute of Clinical Physiology, National Council of Research, via G. Moruzzi 1, 56124 Pisa, Italy.
| | - Andrea Guerrini
- Gruppo Archeologico e Paleontologico Livornese, Museo di Storia Naturale del Mediterraneo, via Roma, 234, 57127 Leghorn, Italy
| | - Simona Minozzi
- Division of Paleopathology, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 57, 56100 Pisa, Italy
| | - Daniele Panetta
- Institute of Clinical Physiology, National Council of Research, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Piero A Salvadori
- Institute of Clinical Physiology, National Council of Research, via G. Moruzzi 1, 56124 Pisa, Italy
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Dutoit CE, Binet L, Vezin H, Anduze O, Lattuati-Derieux A, Gourier D. Insight into the structure of black coatings of ancient Egyptian mummies by advanced electron magnetic resonance of vanadyl complexes. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2022; 3:111-124. [PMID: 37904866 PMCID: PMC10539842 DOI: 10.5194/mr-3-111-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/25/2022] [Indexed: 11/01/2023]
Abstract
Ancient Egyptian mummies from the Late Period to the Greco-Roman Period were covered by a black coating consisting of complex and heterogeneous mixtures of conifer resins, wax, fat and oil with variable amounts of bitumen. Natural bitumen always contains traces of vanadyl porphyrin complexes that we used here as internal probes to explore the nanoscale environment of V4 + ions in these black coatings by electron nuclear double resonance (ENDOR) and hyperfine sub-level correlation spectroscopy (HYSCORE). Four types of vanadyl porphyrin complexes were identified from the analysis of 14 N hyperfine interactions. Three types (referred to as VO-P1, VO-P2 and VO-P3) are present in natural bitumen from the Dead Sea, among which VO-P1 and VO-P2 are also present in black coatings of mummies. The absence of VO-P3 in mummies, which is replaced by another complex, VO-P4, may be due to its transformation during preparation of the black matter for embalming. Analysis of 1 H hyperfine interaction shows that bitumen and other natural substances are intimately mixed in these black coatings, with aggregate sizes of bitumen increasing with the bitumen content but not exceeding a few nanometres.
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Affiliation(s)
- Charles E. Dutoit
- Chimie-ParisTech, PSL University, CNRS, Institut de Recherche de
Chimie-Paris (IRCP), 75005 Paris, France
| | - Laurent Binet
- Chimie-ParisTech, PSL University, CNRS, Institut de Recherche de
Chimie-Paris (IRCP), 75005 Paris, France
| | - Hervé Vezin
- Université de Lille, CNRS, UMR8516-LASIRE, 59000 Lille, France
| | - Océane Anduze
- Chimie-ParisTech, PSL University, CNRS, Institut de Recherche de
Chimie-Paris (IRCP), 75005 Paris, France
| | - Agnès Lattuati-Derieux
- Centre de Recherche et de Restauration des Musées de France
(C2RMF), Palais du Louvre, 75001 Paris, France
| | - Didier Gourier
- Chimie-ParisTech, PSL University, CNRS, Institut de Recherche de
Chimie-Paris (IRCP), 75005 Paris, France
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Fischer J, Özen AC, Ilbey S, Traser L, Echternach M, Richter B, Bock M. Sub-millisecond 2D MRI of the vocal fold oscillation using single-point imaging with rapid encoding. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2021; 35:301-310. [PMID: 34542771 PMCID: PMC8995286 DOI: 10.1007/s10334-021-00959-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/06/2021] [Accepted: 09/06/2021] [Indexed: 10/24/2022]
Abstract
OBJECTIVE The slow spatial encoding of MRI has precluded its application to rapid physiologic motion in the past. The purpose of this study is to introduce a new fast acquisition method and to demonstrate feasibility of encoding rapid two-dimensional motion of human vocal folds with sub-millisecond resolution. METHOD In our previous work, we achieved high temporal resolution by applying a rapidly switched phase encoding gradient along the direction of motion. In this work, we extend phase encoding to the second image direction by using single-point imaging with rapid encoding (SPIRE) to image the two-dimensional vocal fold oscillation in the coronal view. Image data were gated using electroglottography (EGG) and motion corrected. An iterative reconstruction with a total variation (TV) constraint was used and the sequence was also simulated using a motion phantom. RESULTS Dynamic images of the vocal folds during phonation at pitches of 150 and 165 Hz were acquired in two volunteers and the periodic motion of the vocal folds at a temporal resolution of about 600 µs was shown. The simulations emphasize the necessity of SPIRE for two-dimensional motion encoding. DISCUSSION SPIRE is a new MRI method to image rapidly oscillating structures and for the first time provides dynamic images of the vocal folds oscillations in the coronal plane.
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Affiliation(s)
- Johannes Fischer
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Ali Caglar Özen
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,German Consortium for Translational Cancer Research Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Serhat Ilbey
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Louisa Traser
- Freiburg Institute for Musicians' Medicine, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Matthias Echternach
- Division of Phoniatrics and Pediatric Audiology, Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig-Maximilians-University, Munich, Germany
| | - Bernhard Richter
- Freiburg Institute for Musicians' Medicine, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Michael Bock
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Ozen AC, Idiyatullin D, Adriany G, Jungst S, Kobayashi N, Groenke BR, Bock M, Garwood M, Nixdorf DR. Design of an Intraoral Dipole Antenna for Dental Applications. IEEE Trans Biomed Eng 2021; 68:2563-2573. [PMID: 33513097 DOI: 10.1109/tbme.2021.3055777] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE In dental MRI, intraoral coils provide higher signal-to-noise ratio (SNR) than coils placed outside the mouth. This study aims to design an intraoral dipole antenna and demonstrates the feasibility of combining it with an extraoral coil. METHODS Dipole antenna design was chosen over loop design, as it is open toward the distal; therefore, it does not restrain tongue movement. The dipole design offers also an increased depth-of-sensitivity that allows for MRI of dental roots. Different dipole antenna designs were simulated using a finite-difference-time-domain approach. Ribbon, wire, and multi-wire arms were compared. The best design was improved further by covering the ends of the dipole arms with a high-permittivity material. Phantom and in vivo measurements were conducted on a 3T clinical MRI system. RESULTS The best transmit efficiency and homogeneity was achieved with a multi-wire curved dipole antenna with 7 wires for each arm. With an additional high-permittivity cap the transmit field inhomogeneity was further reduced from 20% to 5% along the dipole arm. When combined with extraoral flexible surface-coil, the coupling between the coils was less than -32dB and SNR was increased. CONCLUSION Using intraoral dipole design instead of loop improves patient comfort. We demonstrated feasibility of the intraoral dipole combined with an extraoral flexible coil-array for dental MRI. Dipole antenna enabled decreasing imaging field-of-view, and reduced the prevalent signal from tongue. SIGNIFICANCE This study highlights the advantages and the main challenges of the intraoral RF coils and describes a novel RF coil that addresses those challenges.
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Baadsvik EL, Weiger M, Froidevaux R, Rösler MB, Brunner DO, Öhrström L, Rühli FJ, Eppenberger P, Pruessmann KP. High-resolution MRI of mummified tissues using advanced short-T 2 methodology and hardware. Magn Reson Med 2020; 85:1481-1492. [PMID: 33009877 DOI: 10.1002/mrm.28530] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/11/2022]
Abstract
PURPOSE Evolutionary medicine aims to study disease development from a long-term perspective, and through the analysis of mummified tissue, timescales of several thousand years are unlocked. Due to the status of mummies as ancient relics, noninvasive techniques are preferable, and, currently, CT imaging is the most widespread method. However, CT images lack soft-tissue contrast, making complementary MRI data desirable. Unfortunately, the dehydrated nature and short T2 times of mummified tissues render them practically invisible to standard MRI techniques. Specialized short-T2 approaches have therefore been used, but currently suffer severe resolution limitations. The purpose of the present study is to improve resolution in MRI of mummified tissues. METHODS The zero-TE-based hybrid filling technique, together with a high-performance magnetic field gradient, was used to image three ancient Egyptian mummified human body parts: a hand, a foot, and a head. A similar pairing has already been shown to increase resolution and image quality in MRI of short-T2 tissues. RESULTS MRI images of yet unparalleled image quality were obtained for all samples, reaching isotropic resolutions of 0.6 mm and SNR values above 100. The same general features as present in CT images were depicted but with different contrast, particularly for regions containing embalming substances. CONCLUSION Mummy MRI is a potentially valuable tool for (paleo)pathological studies, as well as for investigations into ancient mummification processes. The results presented here show sufficient improvement in the depiction of mummified tissues to clear new paths for the exploration of this field.
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Affiliation(s)
- Emily Louise Baadsvik
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Romain Froidevaux
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Manuela Barbara Rösler
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - David Otto Brunner
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Lena Öhrström
- Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland
| | - Frank Jakobus Rühli
- Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland
| | - Patrick Eppenberger
- Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland
| | - Klaas Paul Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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Tesfai AS, Fischer J, Özen AC, Eppenberger P, Oehrstroem L, Rühli F, Ludwig U, Bock M. Multi-parameter Analytical Method for B1 and SNR Analysis (MAMBA): An open source RF coil design tool. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 319:106825. [PMID: 32947127 DOI: 10.1016/j.jmr.2020.106825] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/05/2020] [Accepted: 09/03/2020] [Indexed: 06/11/2023]
Abstract
In Magnetic Resonance Imaging (MRI), radio frequency (RF) coils of different forms and shapes are used to maximize signal-to-noise ratio (SNR). RF coils are designed for clinical applications and have dimensions comparable with the target body part to be imaged, and they perform best when loaded by human tissue majority of which have conductivity values higher than 0.5 S/m. However, they are not properly tuned and matched for samples having low conductivity such as solid samples with low water content. Moreover, for samples with low filling factor and low conductivity, the noise in MRI is dominated by RF coil losses. In this case, RF coil design can be optimized to improve image SNR. Here, a new software tool (Multi-parameter Analytical Method for B1 and SNR Analysis) MAMBA is presented to design and compare volume coils of birdcage, solenoid, and loop-gap design for these samples. The input parameters of the tool are the sample properties, the coil design and the hardware properties, of which a relative SNR is determined. For that, a figure of merit is calculated from the coil sensitivity, applied resonant frequency and the resistive losses of sample, coil and capacitive components. The tool was tested in an ancient Egyptian mummy head which represents an extreme case of MRI with short T2*. Two optimized birdcage coils were designed using MAMBA, constructed and compared to a commercial transmit receive head coil. Calculated relative SNR values are in good agreement with the measurements.
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Affiliation(s)
- Agazi Samuel Tesfai
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Johannes Fischer
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ali Caglar Özen
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; German Consortium for Translational Cancer Research Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Patrick Eppenberger
- Institute of Evolutionary Medicine, Faculty of Medicine, University of Zurich, Switzerland
| | - Lena Oehrstroem
- Institute of Evolutionary Medicine, Faculty of Medicine, University of Zurich, Switzerland
| | - Frank Rühli
- Institute of Evolutionary Medicine, Faculty of Medicine, University of Zurich, Switzerland
| | - Ute Ludwig
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Michael Bock
- Dept. of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Weiger M, Pruessmann KP. Short-T 2 MRI: Principles and recent advances. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:237-270. [PMID: 31779882 DOI: 10.1016/j.pnmrs.2019.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/14/2019] [Accepted: 07/26/2019] [Indexed: 06/10/2023]
Abstract
Among current modalities of biomedical and diagnostic imaging, MRI stands out by virtue of its versatile contrast obtained without ionizing radiation. However, in various cases, e.g., water protons in tissues such as bone, tendon, and lung, MRI performance is limited by the rapid decay of resonance signals associated with short transverse relaxation times T2 or T2*. Efforts to address this shortcoming have led to a variety of specialized short-T2 techniques. Recent progress in this field expands the choice of methods and prompts fresh considerations with regard to instrumentation, data acquisition, and signal processing. In this review, the current status of short-T2 MRI is surveyed. In an attempt to structure the growing range of techniques, the presentation highlights overarching concepts and basic methodological options. The most frequently used approaches are described in detail, including acquisition strategies, image reconstruction, hardware requirements, means of introducing contrast, sources of artifacts, limitations, and applications.
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Affiliation(s)
- Markus Weiger
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland.
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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In vivo MRI with Concurrent Excitation and Acquisition using Automated Active Analog Cancellation. Sci Rep 2018; 8:10631. [PMID: 30006628 PMCID: PMC6045667 DOI: 10.1038/s41598-018-28894-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 06/27/2018] [Indexed: 01/28/2023] Open
Abstract
Magnetic resonance imaging (MRI) provides excellent cross-sectional images of the soft tissues in patients. Unfortunately, MRI is intrinsically slow, it exposes patients to severe acoustic noise levels, and is limited in the visualization of certain tissues such as bone. These limitations are partly caused by the timing structure of the MRI exam which first generates the MR signal by a strong radio-frequency excitation and later acquires the weak MRI signal. Concurrent excitation and acquisition (CEA) can overcome these limitations, but is extremely challenging due to the huge intensity difference between transmit and receive signal (up to 100 dB). To suppress the strong transmit signals during signal reception, a fully automated analog cancellation unit was designed. On a 3 Tesla clinical MRI system we achieved an on-resonance analog isolation of 90 dB between the transmit and receive path, so that CEA images of the head and the extremities could be acquired with an acquisition efficiency of higher than 90% at sound pressure levels close to background noise. CEA with analog cancellation might provide new opportunities for MRI in tissues with very short T2 relaxation times, and it offers a silent and time-efficient MRI acquisition.
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