MRI is widely used in hospitals and clinics for medical diagnosis, staging and follow-up of disease. Compared to CT, MRI provides better contrast in images of soft tissues, e.g. in the brain or abdomen. However, it may be perceived as less comfortable by patients, due to the usually longer and louder measurements with the subject in a long, confining tube, although "open" MRI designs mostly relieve this. Additionally, implants and other non-removable metal in the body can pose a risk and may exclude some patients from undergoing an MRI examination safely.
MRI was originally called NMRI (nuclear magnetic resonance imaging), but "nuclear" was dropped to avoid negative associations.[2] Certain atomic nuclei are able to absorb radio frequency (RF) energy when placed in an external magnetic field; the resultant evolving spin polarization can induce an RF signal in a radio frequency coil and thereby be detected.[3] In other words, the nuclear magnetic spin of protons in the hydrogen nuclei resonates with the RF incident waves and emit coherent radiation with compact direction, energy (frequency) and phase. This coherent amplified radiation is easily detected by RF antennas close to the subject being examined. It is a process similar to masers. In clinical and research MRI, hydrogen atoms are most often used to generate a macroscopic polarized radiation that is detected by the antennas.[3] Hydrogen atoms are naturally abundant in humans and other biological organisms, particularly in water and fat. For this reason, most MRI scans essentially map the location of water and fat in the body. Pulses of radio waves excite the nuclear spin energy transition, and magnetic field gradients localize the polarization in space. By varying the parameters of the pulse sequence, different contrasts may be generated between tissues based on the relaxation properties of the hydrogen atoms therein.
Since its development in the 1970s and 1980s, MRI has proven to be a versatile imaging technique. While MRI is most prominently used in diagnostic medicine and biomedical research, it also may be used to form images of non-living objects, such as mummies. Diffusion MRI and functional MRI extend the utility of MRI to capture neuronal tracts and blood flow respectively in the nervous system, in addition to detailed spatial images. The sustained increase in demand for MRI within health systems has led to concerns about cost effectiveness and overdiagnosis.[4][5][dubious – discuss]
In most medical applications, hydrogen nuclei, which consist solely of a proton, that are in tissues create a signal that is processed to form an image of the body in terms of the density of those nuclei in a specific region. Given that the protons are affected by fields from other atoms to which they are bonded, it is possible to separate responses from hydrogen in specific compounds. To perform a study, the person is positioned within an MRI scanner that forms a strong magnetic field around the area to be imaged. First, energy from an oscillating magnetic field is temporarily applied to the patient at the appropriate resonance frequency. Scanning with X and Y gradient coils causes a selected region of the patient to experience the exact magnetic field required for the energy to be absorbed. The atoms are excited by a RF pulse and the resultant signal is measured by a receiving coil. The RF signal may be processed to deduce position information by looking at the changes in RF level and phase caused by varying the local magnetic field using gradient coils. As these coils are rapidly switched during the excitation and response to perform a moving line scan, they create the characteristic repetitive noise of an MRI scan as the windings move slightly due to magnetostriction. The contrast between different tissues is determined by the rate at which excited atoms return to the equilibrium state. Exogenouscontrast agents may be given to the person to make the image clearer.[6]
The major components of an MRI scanner are the main magnet, which polarizes the sample, the shim coils for correcting shifts in the homogeneity of the main magnetic field, the gradient system which is used to localize the region to be scanned and the RF system, which excites the sample and detects the resulting NMR signal. The whole system is controlled by one or more computers.
MRI requires a magnetic field that is both strong and uniform to a few parts per million across the scan volume. The field strength of the magnet is measured in teslas – and while the majority of systems operate at 1.5 T, commercial systems are available between 0.2 and 7 T. 3T MRI systems, also called 3 Tesla MRIs, have stronger magnets than 1.5 systems and are considered better for images of organs and soft tissue.[7] Whole-body MRI systems for research applications operate in e.g. 9.4T,[8][9] 10.5T,[10] 11.7T.[11] Even higher field whole-body MRI systems e.g. 14 T and beyond are in conceptual proposal[12] or in engineering design.[13] Most clinical magnets are superconducting magnets, which require liquid helium to keep them at low temperatures. Lower field strengths can be achieved with permanent magnets, which are often used in "open" MRI scanners for claustrophobic patients.[14] Lower field strengths are also used in a portable MRI scanner approved by the FDA in 2020.[15] Recently, MRI has been demonstrated also at ultra-low fields, i.e., in the microtesla-to-millitesla range, where sufficient signal quality is made possible by prepolarization (on the order of 10–100 mT) and by measuring the Larmor precession fields at about 100 microtesla with highly sensitive superconducting quantum interference devices (SQUIDs).[16][17][18]
Each tissue returns to its equilibrium state after excitation by the independent relaxation processes of T1 (spin-lattice; that is, magnetization in the same direction as the static magnetic field) and T2 (spin-spin; transverse to the static magnetic field).
To create a T1-weighted image, magnetization is allowed to recover before measuring the MR signal by changing the repetition time (TR). This image weighting is useful for assessing the cerebral cortex, identifying fatty tissue, characterizing focal liver lesions, and in general, obtaining morphological information, as well as for post-contrast imaging.
To create a T2-weighted image, magnetization is allowed to decay before measuring the MR signal by changing the echo time (TE). This image weighting is useful for detecting edema and inflammation, revealing white matter lesions, and assessing zonal anatomy in the prostate and uterus.
The information from MRI scans comes in the form of image contrasts based on differences in the rate of relaxation of nuclear spins following their perturbation by an oscillating magnetic field (in the form of radiofrequency pulses through the sample).[19] The relaxation rates are a measure of the time it takes for a signal to decay back to an equilibrium state from either the longitudinal or transverse plane.
Magnetization builds up along the z-axis in the presence of a magnetic field, B0, such that the magnetic dipoles in the sample will, on average, align with the z-axis summing to a total magnetization Mz. This magnetization along z is defined as the equilibrium magnetization; magnetization is defined as the sum of all magnetic dipoles in a sample. Following the equilibrium magnetization, a 90° radiofrequency (RF) pulse flips the direction of the magnetization vector in the xy-plane, and is then switched off. The initial magnetic field B0, however, is still applied. Thus, the spin magnetization vector will slowly return from the xy-plane back to the equilibrium state. The time it takes for the magnetization vector to return to its equilibrium value, Mz, is referred to as the longitudinal relaxation time, T1.[20] Subsequently, the rate at which this happens is simply the reciprocal of the relaxation time: . Similarly, the time in which it takes for Mxy to return to zero is T2, with the rate .[21] Magnetization as a function of time is defined by the Bloch equations.
T1 and T2 values are dependent on the chemical environment of the sample; hence their utility in MRI. Soft tissue and muscle tissue relax at different rates, yielding the image contrast in a typical scan.
The standard display of MR images is to represent fluid characteristics in black-and-white images, where different tissues turn out as follows:
MRI has a wide range of applications in medical diagnosis and around 50,000 scanners are estimated to be in use worldwide.[25] MRI affects diagnosis and treatment in many specialties although the effect on improved health outcomes is disputed in certain cases.[26][27]
MRI is the investigation of choice in the preoperative staging of rectal and prostate cancer and has a role in the diagnosis, staging, and follow-up of other tumors,[28] as well as for determining areas of tissue for sampling in biobanking.[29][30]
The record for the highest spatial resolution of a whole intact brain (postmortem) is 100 microns, from Massachusetts General Hospital. The data was published in NATURE on 30 October 2019.[39][40]
Though MRI is used widely in research on mental disabilities, based on a 2024 systematic literature review and meta analysis commissioned by the Patient-Centered Outcomes Research Institute (PCORI), available research using MRI scans to diagnose ADHD showed great variability.[41] The authors conclude that MRI cannot be reliably used to assist in making a clinical diagnosis of ADHD.[41]
Swallowing movement of throat and oesophagus can cause motion artifact over the imaged spine. Therefore, a saturation pulse[clarification needed] applied over this region the throat and oesophagus can help to avoid this artifact. Motion artifact arising due to pumping of the heart can be reduced by timing the MRI pulse according to heart cycles.[47] Blood vessels flow artifacts can be reduced by applying saturation pulses above and below the region of interest.[48]
Liver and gastrointestinal
Hepatobiliary MR is used to detect and characterize lesions of the liver, pancreas, and bile ducts. Focal or diffuse disorders of the liver may be evaluated using diffusion-weighted, opposed-phase imaging and dynamic contrast enhancement sequences. Extracellular contrast agents are used widely in liver MRI, and newer hepatobiliary contrast agents also provide the opportunity to perform functional biliary imaging. Anatomical imaging of the bile ducts is achieved by using a heavily T2-weighted sequence in magnetic resonance cholangiopancreatography (MRCP). Functional imaging of the pancreas is performed following administration of secretin. MR enterography provides non-invasive assessment of inflammatory bowel disease and small bowel tumors. MR-colonography may play a role in the detection of large polyps in patients at increased risk of colorectal cancer.[49][50][51][52]
Magnetic resonance angiography (MRA) generates pictures of the arteries to evaluate them for stenosis (abnormal narrowing) or aneurysms (vessel wall dilatations, at risk of rupture). MRA is often used to evaluate the arteries of the neck and brain, the thoracic and abdominal aorta, the renal arteries, and the legs (called a "run-off"). A variety of techniques can be used to generate the pictures, such as administration of a paramagnetic contrast agent (gadolinium) or using a technique known as "flow-related enhancement" (e.g., 2D and 3D time-of-flight sequences), where most of the signal on an image is due to blood that recently moved into that plane (see also FLASH MRI).[53]
Techniques involving phase accumulation (known as phase contrast angiography) can also be used to generate flow velocity maps easily and accurately. Magnetic resonance venography (MRV) is a similar procedure that is used to image veins. In this method, the tissue is now excited inferiorly, while the signal is gathered in the plane immediately superior to the excitation plane—thus imaging the venous blood that recently moved from the excited plane.[54]
MRI for imaging anatomical structures or blood flow do not require contrast agents since the varying properties of the tissues or blood provide natural contrasts. However, for more specific types of imaging, exogenous contrast agents may be given intravenously, orally, or intra-articularly.[6] Most contrast agents are either paramagnetic (e.g.: gadolinium, manganese, europium), and are used to shorten T1 in the tissue they accumulate in, or super-paramagnetic (SPIONs), and are used to shorten T2 and T2* in healthy tissue reducing its signal intensity (negative contrast agents). The most commonly used intravenous contrast agents are based on chelates of gadolinium, which is highly paramagnetic.[55] In general, these agents have proved safer than the iodinated contrast agents used in X-ray radiography or CT. Anaphylactoid reactions are rare, occurring in approx. 0.03–0.1%.[56] Of particular interest is the lower incidence of nephrotoxicity, compared with iodinated agents, when given at usual doses—this has made contrast-enhanced MRI scanning an option for patients with renal impairment, who would otherwise not be able to undergo contrast-enhanced CT.[57]
Gadolinium-based contrast reagents are typically octadentate complexes of gadolinium(III). The complex is very stable (log K > 20) so that, in use, the concentration of the un-complexed Gd3+ ions should be below the toxicity limit. The 9th place in the metal ion's coordination sphere is occupied by a water molecule which exchanges rapidly with water molecules in the reagent molecule's immediate environment, affecting the magnetic resonance relaxation time.[58]
In December 2017, the Food and Drug Administration (FDA) in the United States announced in a drug safety communication that new warnings were to be included on all gadolinium-based contrast agents (GBCAs). The FDA also called for increased patient education and requiring gadolinium contrast vendors to conduct additional animal and clinical studies to assess the safety of these agents.[59]
Although gadolinium agents have proved useful for patients with kidney impairment, in patients with severe kidney failure requiring dialysis there is a risk of a rare but serious illness, nephrogenic systemic fibrosis, which may be linked to the use of certain gadolinium-containing agents. The most frequently linked is gadodiamide, but other agents have been linked too.[60] Although a causal link has not been definitively established, current guidelines in the United States are that dialysis patients should only receive gadolinium agents where essential and that dialysis should be performed as soon as possible after the scan to remove the agent from the body promptly.[61][62]
In Europe, where more gadolinium-containing agents are available, a classification of agents according to potential risks has been released.[63][64] In 2008, a new contrast agent named gadoxetate, brand name Eovist (US) or Primovist (EU), was approved for diagnostic use: This has the theoretical benefit of a dual excretion path.[65]
An MRI sequence is a particular setting of radiofrequency pulses and gradients, resulting in a particular image appearance.[66] The T1 and T2 weighting can also be described as MRI sequences.
Low signal for fat in standard Spine Echo (SE),[67] though not with Fast Spin Echo/Turbo Spin Echo (FSE/TSE). FSE/TSE is the standard of care in modern medicine because it is faster. With FSE/TSE, fat has high signal due to disruption of hyperfineJ-coupling between adjacent fat protons.[69]
Magnetic labeling of arterial blood below the imaging slab, which subsequently enters the region of interest.[88] It does not need gadolinium contrast.[89]
Magnetic resonance spectroscopy (MRS) is used to measure the levels of different metabolites in body tissues, which can be achieved through a variety of single voxel or imaging-based techniques.[96] The MR signal produces a spectrum of resonances that corresponds to different molecular arrangements of the isotope being "excited". This signature is used to diagnose certain metabolic disorders, especially those affecting the brain,[97] and to provide information on tumor metabolism.[98]
Magnetic resonance spectroscopic imaging (MRSI) combines both spectroscopic and imaging methods to produce spatially localized spectra from within the sample or patient. The spatial resolution is much lower (limited by the available SNR), but the spectra in each voxel contains information about many metabolites. Because the available signal is used to encode spatial and spectral information, MRSI requires high SNR achievable only at higher field strengths (3 T and above).[99] The high procurement and maintenance costs of MRI with extremely high field strengths[100] inhibit their popularity. However, recent compressed sensing-based software algorithms (e.g., SAMV[101]) have been proposed to achieve super-resolution without requiring such high field strengths.
Real-time magnetic resonance imaging (RT-MRI) refers to the continuous monitoring of moving objects in real time. Traditionally, real-time MRI was possible only with low image quality or low temporal resolution. An iterative reconstruction algorithm removed limitations. Radial FLASH MRI (real-time) yields a temporal resolution of 20 to 30 milliseconds for images with an in-plane resolution of 1.5 to 2.0 mm.[103] Real-time MRI adds information about diseases of the joints and the heart. In many cases MRI examinations become easier and more comfortable for patients, especially for the patients who cannot calm their breathing[104] or who have arrhythmia.
The lack of harmful effects on the patient and the operator make MRI well-suited for interventional radiology, where the images produced by an MRI scanner guide minimally invasive procedures. Such procedures use no ferromagnetic instruments.[105]
A specialized growing subset of interventional MRI is intraoperative MRI, in which an MRI is used in surgery. Some specialized MRI systems allow imaging concurrent with the surgical procedure. More typically, the surgical procedure is temporarily interrupted so that MRI can assess the success of the procedure or guide subsequent surgical work.[106]
Magnetic resonance guided focused ultrasound
In guided therapy, high-intensity focused ultrasound (HIFU) beams are focused on a tissue, that are controlled using MR thermal imaging. Due to the high energy at the focus, the temperature rises to above 65 °C (150 °F) which completely destroys the tissue. This technology can achieve precise ablation of diseased tissue. MR imaging provides a three-dimensional view of the target tissue, allowing for the precise focusing of ultrasound energy. The MR imaging provides quantitative, real-time, thermal images of the treated area. This allows the physician to ensure that the temperature generated during each cycle of ultrasound energy is sufficient to cause thermal ablation within the desired tissue and if not, to adapt the parameters to ensure effective treatment.[107]
Hydrogen has the most frequently imaged nucleus in MRI because it is present in biological tissues in great abundance, and because its high gyromagnetic ratio gives a strong signal. However, any nucleus with a net nuclear spin could potentially be imaged with MRI. Such nuclei include helium-3, lithium-7, carbon-13, fluorine-19, oxygen-17, sodium-23, phosphorus-31 and xenon-129. 23Na and 31P are naturally abundant in the body, so they can be imaged directly. Gaseous isotopes such as 3He or 129Xe must be hyperpolarized and then inhaled as their nuclear density is too low to yield a useful signal under normal conditions. 17O and 19F can be administered in sufficient quantities in liquid form (e.g. 17O-water) that hyperpolarization is not a necessity.[108] Using helium or xenon has the advantage of reduced background noise, and therefore increased contrast for the image itself, because these elements are not normally present in biological tissues.[109]
Moreover, the nucleus of any atom that has a net nuclear spin and that is bonded to a hydrogen atom could potentially be imaged via heteronuclear magnetization transfer MRI that would image the high-gyromagnetic-ratio hydrogen nucleus instead of the low-gyromagnetic-ratio nucleus that is bonded to the hydrogen atom.[110] In principle, heteronuclear magnetization transfer MRI could be used to detect the presence or absence of specific chemical bonds.[111][112]
Multinuclear imaging is primarily a research technique at present. However, potential applications include functional imaging and imaging of organs poorly seen on 1H MRI (e.g., lungs and bones) or as alternative contrast agents. Inhaled hyperpolarized 3He can be used to image the distribution of air spaces within the lungs. Injectable solutions containing 13C or stabilized bubbles of hyperpolarized 129Xe have been studied as contrast agents for angiography and perfusion imaging. 31P can potentially provide information on bone density and structure, as well as functional imaging of the brain. Multinuclear imaging holds the potential to chart the distribution of lithium in the human brain, this element finding use as an important drug for those with conditions such as bipolar disorder.[113]
MRI has the advantages of having very high spatial resolution and is very adept at morphological imaging and functional imaging. MRI does have several disadvantages though. First, MRI has a sensitivity of around 10−3mol/L to 10−5 mol/L, which, compared to other types of imaging, can be very limiting. This problem stems from the fact that the population difference between the nuclear spin states is very small at room temperature. For example, at 1.5 teslas, a typical field strength for clinical MRI, the difference between high and low energy states is approximately 9 molecules per 2 million. Improvements to increase MR sensitivity include increasing magnetic field strength and hyperpolarization via optical pumping or dynamic nuclear polarization. There are also a variety of signal amplification schemes based on chemical exchange that increase sensitivity.[114]
To achieve molecular imaging of disease biomarkers using MRI, targeted MRI contrast agents with high specificity and high relaxivity (sensitivity) are required. To date, many studies have been devoted to developing targeted-MRI contrast agents to achieve molecular imaging by MRI. Commonly, peptides, antibodies, or small ligands, and small protein domains, such as HER-2 affibodies, have been applied to achieve targeting. To enhance the sensitivity of the contrast agents, these targeting moieties are usually linked to high payload MRI contrast agents or MRI contrast agents with high relaxivities.[115] A new class of gene targeting MR contrast agents has been introduced to show gene action of unique mRNA and gene transcription factor proteins.[116][117] These new contrast agents can trace cells with unique mRNA, microRNA and virus; tissue response to inflammation in living brains.[118] The MR reports change in gene expression with positive correlation to TaqMan analysis, optical and electron microscopy.[119]
Parallel MRI
It takes time to gather MRI data using sequential applications of magnetic field gradients. Even for the most streamlined of MRI sequences, there are physical and physiologic limits to the rate of gradient switching. Parallel MRI circumvents these limits by gathering some portion of the data simultaneously, rather than in a traditional sequential fashion. This is accomplished using arrays of radiofrequency (RF) detector coils, each with a different 'view' of the body. A reduced set of gradient steps is applied, and the remaining spatial information is filled in by combining signals from various coils, based on their known spatial sensitivity patterns. The resulting acceleration is limited by the number of coils and by the signal to noise ratio (which decreases with increasing acceleration), but two- to four-fold accelerations may commonly be achieved with suitable coil array configurations, and substantially higher accelerations have been demonstrated with specialized coil arrays. Parallel MRI may be used with most MRI sequences.
After a number of early suggestions for using arrays of detectors to accelerate imaging went largely unremarked in the MRI field, parallel imaging saw widespread development and application following the introduction of the SiMultaneous Acquisition of Spatial Harmonics (SMASH) technique in 1996–7.[120] The SENSitivity Encoding (SENSE)[121] and Generalized Autocalibrating Partially Parallel Acquisitions (GRAPPA)[122] techniques are the parallel imaging methods in most common use today. The advent of parallel MRI resulted in extensive research and development in image reconstruction and RF coil design, as well as in a rapid expansion of the number of receiver channels available on commercial MR systems. Parallel MRI is now used routinely for MRI examinations in a wide range of body areas and clinical or research applications.
Quantitative MRI
Most MRI focuses on qualitative interpretation of MR data by acquiring spatial maps of relative variations in signal strength which are "weighted" by certain parameters.[123] Quantitative methods instead attempt to determine spatial maps of accurate tissue relaxometry parameter values or magnetic field, or to measure the size of certain spatial features.
Quantitative MRI aims to increase the reproducibility of MR images and interpretations, but has historically require longer scan times.[123]
Quantitative MRI (or qMRI) sometimes more specifically refers to multi-parametric quantitative MRI, the mapping of multiple tissue relaxometry parameters in a single imaging session.[128]
Efforts to make multi-parametric quantitative MRI faster have produced sequences which map multiple parameters simultaneously, either by building separate encoding methods for each parameter into the sequence,[129]
or by fitting MR signal evolution to a multi-parameter model.[130][131]
Traditional MRI generates poor images of lung tissue because there are fewer water molecules with protons that can be excited by the magnetic field. Using hyperpolarized gas an MRI scan can identify ventilation defects in the lungs. Before the scan, a patient is asked to inhale hyperpolarized xenon mixed with a buffer gas of helium or nitrogen. The resulting lung images are much higher quality than with traditional MRI.
MRI is, in general, a safe technique, although injuries may occur as a result of failed safety procedures or human error.[132]Contraindications to MRI include most cochlear implants and cardiac pacemakers, shrapnel, and metallic foreign bodies in the eyes. Magnetic resonance imaging in pregnancy appears to be safe, at least during the second and third trimesters if done without contrast agents.[133] Since MRI does not use any ionizing radiation, its use is generally favored in preference to CT when either modality could yield the same information.[134] Some patients experience claustrophobia and may require sedation or shorter MRI protocols.[135][136] Amplitude and rapid switching of gradient coils during image acquisition may cause peripheral nerve stimulation.[137]
MRI uses powerful magnets and can therefore cause magnetic materials to move at great speeds, posing a projectile risk, and may cause fatal accidents.[138] However, as millions of MRIs are performed globally each year,[139] fatalities are extremely rare.[140]
Medical societies issue guidelines for when physicians should use MRI on patients and recommend against overuse. MRI can detect health problems or confirm a diagnosis, but medical societies often recommend that MRI not be the first procedure for creating a plan to diagnose or manage a patient's complaint. A common case is to use MRI to seek a cause of low back pain; the American College of Physicians, for example, recommends against imaging (including MRI) as unlikely to result in a positive outcome for the patient.[26][27]
An MRI artifact is a visual artifact, that is, an anomaly during visual representation. Many different artifacts can occur during magnetic resonance imaging (MRI), some affecting the diagnostic quality, while others may be confused with pathology. Artifacts can be classified as patient-related, signal processing-dependent and hardware (machine)-related.[142]
MRI is used industrially mainly for routine analysis of chemicals. The nuclear magnetic resonance technique is also used, for example, to measure the ratio between water and fat in foods, monitoring of flow of corrosive fluids in pipes, or to study molecular structures such as catalysts.[1]
Being non-invasive and non-damaging, MRI can be used to study the anatomy of plants, their water transportation processes and water balance.[143] It is also applied to veterinary radiology for diagnostic purposes. Outside this, its use in zoology is limited due to the high cost; but it can be used on many species.[144]
In palaeontology it is used to examine the structure of fossils.[145]
Forensic imaging provides graphic documentation of an autopsy, which manual autopsy does not. CT scanning provides quick whole-body imaging of skeletal and parenchymal alterations, whereas MR imaging gives better representation of soft tissue pathology.[146] All that being said, MRI is more expensive, and more time-consuming to utilize.[146] Moreover, the quality of MR imaging deteriorates below 10 °C.[147]
In 1971 at Stony Brook University, Paul Lauterbur applied magnetic field gradients in all three dimensions and a back-projection technique to create NMR images. He published the first images of two tubes of water in 1973 in the journal Nature,[148] followed by the picture of a living animal, a clam, and in 1974 by the image of the thoracic cavity of a mouse. Lauterbur called his imaging method zeugmatography, a term which was replaced by (N)MR imaging.[1] In the late 1970s, physicists Peter Mansfield and Paul Lauterbur developed MRI-related techniques, like the echo-planar imaging (EPI) technique.[149]
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L'article Religion en Finlande recense l'histoire et l'actualité de la religion des 5 500 000 Finlandais. Histoire Préhistoire et protohistoire Les premières installations sur le territoire finlandais remontent à 8300 av. J.-C., et l'ère préhistorique dure sur ce territoire pratiquement jusqu'au 13e siècle. Les populations autochtones, depuis la préhistoire, au nord comme au sud, sont des Samis, peuple finno-ougrien. La côte sud-ouest, originellement peuplée par ...
Cet article est une ébauche concernant la littérature roumaine. Vous pouvez partager vos connaissances en l’améliorant (comment ?) selon les recommandations des projets correspondants. La littérature roumaine désigne ici l'ensemble des littératures orales et écrites, en roumain, en Roumanie ou par des Roumains, de toute époque, de toute origine, de toute langue, ce qui inclut minorités, diasporas, exils. Le plus ancien texte connu en roumain est la lettre de Neacșu, une lettr...
Suburb of Moreton Bay, Queensland, AustraliaCashmereMoreton Bay, QueenslandCashmere Village Shopping Centre, 2023CashmereCoordinates27°17′36″S 152°54′11″E / 27.2933°S 152.9030°E / -27.2933; 152.9030 (Cashmere (centre of suburb))Population4,920 (2016 census)[1] • Density142.2/km2 (368.3/sq mi)Postcode(s)4500Area34.6 km2 (13.4 sq mi)Time zoneAEST (UTC+10:00)Location 8.2 km (5 mi) W of Strathpine 2...
Cet article est une ébauche concernant la peinture italienne et les galeries des Offices. Vous pouvez partager vos connaissances en l’améliorant (comment ?) selon les recommandations des projets correspondants. Consultez la liste des tâches à accomplir en page de discussion. Pour les articles homonymes, voir Annonciation (homonymie) et L'Annonciation (Botticelli). L'Annonciation de San Martino alla ScalaArtiste Sandro BotticelliDate 1481Type Art sacréTechnique fresqueDimensions...
أسرع من الضوء (بالإنجليزية Faster-than-light، واختصارا FTL) يشير إلى انتقال المعلومات أو المادة بسرعة أكبر من سرعة الضوء. تشير نظرية النسبية الخاصة إلى أن الجزيئات ذات الكتلة الصفرية فقط يمكنها السفر بسرعة الضوء. تم افتراض التاكيون –جزيئات تتخطى سرعتها سرعة الضوء- إلا أن وجودها قد يخ
British protectorate from 1893 to 1907 For the later history of this protectorate, see Nyasaland. British Central Africa Protectorate1893–1907 Flag Coat of arms Motto: Light in DarknessAnthem: God Save the Queen/King Map of southern Africa, 1897. The British Central Africa Protectorate is shaded dark pink.StatusProtectorate of British EmpireCapitalZombaCommon languagesEnglish (official)Chewa, Yao, TumbukaReligion Christianity, Islam, Bantu mythology, Tumbuka religionGove...
Universitas Islam Negeri Raden Mas Said SurakartaJenisPerguruan tinggi Islam negeri di IndonesiaDidirikan12 September 1992Lembaga indukKementerian Agama Republik IndonesiaAfiliasiIslamRektorProf. Dr. Toto Suharto, S.Ag., M.Ag.LokasiJalan Pandawa, Pucangan, Kartasura, Sukoharjo, Jawa TengahKampus± 14 HaSitus webwww.uinsaid.ac.id Universitas Islam Negeri Raden Mas Said (UIN RMS) Surakarta, yang dahulu bernama Sekolah Tinggi Agama Islam Negeri (STAIN) Surakarta kemudian berubah alih status menj...
Çeltikçi Hilfe zu Wappen Çeltikçi (Burdur) (Türkei) Basisdaten Provinz (il): Burdur Koordinaten: 37° 32′ N, 30° 29′ O37.53444444444430.484444444444Koordinaten: 37° 32′ 4″ N, 30° 29′ 4″ O Einwohner: 2.010[1] (2020) Telefonvorwahl: (+90) 248 Postleitzahl: 15 070 Kfz-Kennzeichen: 15 Struktur und Verwaltung (Stand: 2021) Gliederung: 2 Mahalle Belediye Başkanı: Recep Aydın (MHP) Postanschrift: Konak MahallesiAdnan Me...
Indian film actor (born 1942) Amitabh BachchanBachchan in 2018BornAmitabh Srivastava[1] (1942-10-11) 11 October 1942 (age 81)Allahabad, United Provinces, British India (present-day Prayagraj, Uttar Pradesh, India)NationalityIndianOther namesAmit[2][3]EducationBoys' High School and CollegeSherwood CollegeAlma materKirori Mal College, University of Delhi (BS)[4][5][6]OccupationsActorproducersingertelevision presenterYears activ...
Lihat pula: Kekaisaran Rusia Ketsaran RusiaЦарство РусcкоеTsarstvo Russkoye1547–1721 Bendera Lambang Wilayah teritorial Rusia pada tahun 1500-1700.Ibu kotaMoskwa(1547–1712) Kremlin Alexandrov(1564–1581) St. Petersburg(1712–1721)Bahasa yang umum digunakanRusiaAgama Kristen OrtodoksPemerintahanMonarki absolut , otokrasi tsarTsar (Kaisar) • 1547–1584 Ivan IV (pertama)• 1682–1721 Pyotr I (terakhir) LegislatifZemsky SoborSejarah • Penoba...
Nigerian songs chart TurnTable Nigeria Top 100 SongsFormation3 July 2020; 3 years ago (2020-07-03)PurposeTo award trending top songsServicesrecord chartOwnerTurnTableWebsitetop100 The TurnTable Top 100 (also known as TurnTable Nigeria Top 100) is the music industry standard record chart in Nigeria for songs, published weekly by TurnTable magazine. Chart rankings are based on airplay (radio and tv) and online streaming in Nigeria. In its opening year, TurnTable charts listed ...
Turkish astrophysicist (1926–2012) Dilhan EryurtBorn(1926-11-29)29 November 1926İzmir, TurkeyDied13 September 2012(2012-09-13) (aged 85)Ankara, TurkeyAlma materIstanbul UniversityUniversity of MichiganUniversity of AnkaraAwardsApollo Achievement AwardTübitak Science AwardScientific careerFieldsAstrophysics (Heliology)InstitutionsIndiana UniversityGoethe Link ObservatoryGoddard Institute for Space StudiesMiddle East Technical UniversityNASA Dilhan Eryurt (29 November 1926 – 13 ...
Stem cells that give rise to other blood cells This article may be too technical for most readers to understand. Please help improve it to make it understandable to non-experts, without removing the technical details. (August 2015) (Learn how and when to remove this template message) Hematopoietic stem cellOverview of normal human haematopoiesisDetailsPrecursorHemangioblastSystemHematopoietic systemLocationBone marrowFunctionStem cells that give rise to other blood cellsIdentifiersLatinCellul...
Singaporean brand of beer TigerLogo of Tiger BeerManufacturerHeineken Asia PacificFraser and NeaveRegion of originSingaporeIntroduced1932; 91 years ago (1932)Alcohol by volume 5% pilsnerStyleLagerWebsitewww.tigerbeer.com 330ml bottle of Tiger Beer Advert for Tiger Beer in a Singapore Amateur Football Association's handbook in 1952 Tiger Beer is a Singapore brand of beer first launched in 1932. It is currently produced by Heineken Asia Pacific, formerly known as As...
Untuk kegunaan lain, lihat Titik kritis. Foto fase cair dari etana pada kondisi subkritis (Gambar 1). Pada kondisi kritis (Gambar 2), yang dicapai pada suhu 32.17 °C dan tekanan 48.72 bar, etana terlihat keruh (fase gas dan cair bersamaan). Gambar 3 menunjukkan etana pada kondisi superkritis.[1] Dalam termodinamika, titik kritis adalah titik akhir kurva kesetimbangan fasa. Contoh yang paling umum adalah titik kritis uap-cair, titik akhir kurva suhu-tekanan yang menunjukkan ...
This article does not cite any sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Grotenburg-Stadion – news · newspapers · books · scholar · JSTOR (July 2014) (Learn how and when to remove this template message) Grotenburg-StadionGrotenburgGrotenburg-StadionLocationKrefeldOwnerCity of KrefeldCapacity34,500 (10,868 for safety reasons)SurfacegrassOpenedSeptembe...
Indian political party Political party in India Goa Suraksha Manch AbbreviationGSMLeaderSubhash VelingkarPresidentAtmaram GaonkarFounderSubhash VelingkarFounded2 October 2016; 7 years ago (2016-10-02)HeadquartersShop No. 644/1, Ward No. 4, Ground Floor, Ahilyaram Niwas, Savaiverem, Ponda, GoaIdeologyRegionalismColoursYellow ECI StatusUnrecognised Party[1]Seats in Goa Legislative Assembly0 / 40 Election symbolBlackboardPolitics of IndiaPolitical ...
أولريكه ريشتر (بالألمانية: Ulrike Richter) معلومات شخصية الميلاد 17 يونيو 1959 (العمر 64 سنة)غرليتز مواطنة ألمانيا ألمانيا الشرقية الطول 173 سنتيمتر الحياة العملية المهنة سبّاحة اللغات الألمانية الرياضة السباحة[1] الجوائز قاعة مشاهير السباحة العالمية [...
心音「心音(しんおん)」中島美雪的单曲收录于专辑《<愛麗絲與特蕾斯的虛幻工廠>原聲音樂集》语言日語B面失誤者們 (日语:有謬の者共)发行日期2023年9月13日格式Maxi Single类型J-POP動畫歌曲唱片公司雅馬哈音樂傳播词曲中島美雪排行榜最高名次 週榜第15名(Oricon)[1] 週榜第96名(Billboard Japan Hot 100)[2] 週榜第16名(Billboard Japan Download Songs)[3] 中島美...