MR postprocessing
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Epilepsie je jedno z nejčastějších závažných neurologických onemocnění. I přes významný pokrok v neurozobrazovacích metodách stále existuje mnoho strukturálních změn, které mohou být v kauzální souvislosti s epilepsií a jež nemusí být vizuálně prokázány při klasickém MR či CT vyšetření (např. řada malformací kortikálního vývoje). Bylo vytvořeno několik matematických metod, využívajících MR obrazy, k detekci morfologicky změněné tkáně a zvyšující tak citlivost vyšetření. V anglické literatuře se tyto postupy nazývají MRI postprocessing (Jackson et al., 2010). Tyto metody pak mohou výrazně napomáhat v detekci diskrétních epileptogenních lézí a stát se tak významnou součástí předoperačního vyšetření v rámci epileptochirurgického programu.
Epilepsy is one of the most common neurologic disease. Despite the improvement of the neuroimaging methods several structural pathologies (especially malformations of the cortical development – MCD), which are in the clear-cut causation of disease, do not have to be detected by classical CT or MRI examination. Because visual evaluation of MRI remains difficult to detect some subtle abnormalities, several neuroimaging approaches, methods and modalities have been established to improve detection and localization of MCD. These methods are called in expert literature as a MRI postprocessing. (Jackson at al., 2010). This specific approaches enable to detect the morphological changes of brain structure not detected by visually inspections of MRI scans and due to their superior contribution in the determination of MCD, they might be the indivisible part of a presurgical evaluation of brain.
- Klíčová slova
- voxel–based morfometrie, automatizovaný kurvilineární model, junctions,
- MeSH
- epilepsie diagnóza patologie MeSH
- financování organizované MeSH
- fokální kortikální dysplazie MeSH
- léková rezistence MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- malformace mozkové kůry diagnóza patologie MeSH
- modely neurologické MeSH
- mozek anatomie a histologie patologie MeSH
- počítačové zpracování obrazu metody MeSH
- statistické modely MeSH
- zobrazování trojrozměrné MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Magnetic Resonance Imaging (MRI) has revolutionized our ability to non-invasively study the brain's structural and functional properties. However, detecting myelin, a crucial component of white matter, remains challenging due to its indirect visibility on conventional MRI scans. Myelin plays a vital role in neural signal transmission and is associated with various neurological conditions. Understanding myelin distribution and content is crucial for insights into brain development, aging, and neurological disorders. Although specialized MRI sequences can estimate myelin content, these are time-consuming. Also, many patients sent to specialized neurological centers have an MRI of the brain already scanned. In this study, we focused on techniques utilizing standard MRI T1-weighted (T1w) and T2 weighted (T2w) sequences commonly used in brain imaging protocols. We evaluated the applicability of the T1w/T2w ratio in assessing myelin content by comparing it to quantitative T1 mapping (qT1). Our study included 1 healthy adult control and 7 neurologic patients (comprising both pediatric and adult populations) with epilepsy originating from focal epileptogenic lesions visible on MRI structural scans. Following image acquisition on a 3T Siemens Vida scanner, datasets were co registered, and segmented into anatomical regions using the Fastsurfer toolbox, and T1w/T2w ratio maps were calculated in Matlab software. We further assessed interhemispheric differences in volumes of individual structures, their signal intensity, and the correlation of the T1w/T2w ratio to qT1. Our data demonstrate that in situations where a dedicated myelin-sensing sequence such as qT1 is not available, the T1w/T2w ratio provides significantly better information than T1w alone. By providing indirect information about myelin content, this technique offers a valuable tool for understanding the neurobiology of myelin-related conditions using basic brain scans.
... Phase Contrast MR Angiography 43 -- 5.4. Stenosis Grading 45 -- References 46 -- 6. ... ... Bolus Timing 50 -- MEDCOR EUROPE PUBLISHER • Josef Vymazal • Cardiovascular MR! -- 6.3.1. /? ... ... Postprocessing of MRA 61 -- 6.6.1. Multiplanar Reconstruction (MPR) 61 -- 6.6.2. ... ... Non-Contrast MR Angiography 68 -- 7.4. Comparison of Different Methods • • 68 -- 7.5. ... ... Postprocessing 103 -- 9.10. Pitfalls 103 -- 9.10.1. Venous Contamination 103 -- 9.10.2. ...
First edition 125 stran : ilustrace, tabulky ; 31 cm
- MeSH
- angiografie metody MeSH
- gadolinium MeSH
- kardiovaskulární nemoci diagnostické zobrazování MeSH
- kontrastní látky MeSH
- magnetická rezonanční tomografie metody MeSH
- perfuzní zobrazování metody MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- kardiologie
- angiologie
- radiologie, nukleární medicína a zobrazovací metody
- NLK Publikační typ
- kolektivní monografie
Magnetická rezonancia (MR) sa stala v náročnom procese diagnostiky sclerosis multiplex (SM) dôležitou podpornou vyšetrovacou metódou, ktorá bola zahrnutá v roku 2001 do diagnostických kritérií (McDonald kritériá SM 2001). Následne tieto kritériá prešli úpravou v roku 2005 a 2010 s cieľom zvýšiť ich senzitivitu, pri zachovaní ich špecificity. MR je v súčasnosti najviac využívaný biomarker v procese diagnostiky, v stanovení prognózy a v monitorovaní priebehu ochorenia, pričom využíva konvenčné a nekonvenčné techniky. Ku konvenčným technikám patrí T1 vážený obraz bez/alebo s podaním kontrastnej látky, T2 vážené obrazy (T2vo), z ktorých postprocesingom pri použití jemných rezov sa môže určiť objem ložísk (tzv. lesion load) na sledovanie zápalu alebo pri prevahe neurodegenerácie u pacienta môžeme merať atrofiu mozgu. Nekonvenčné techniky sa uplatňujú v experimentálnych prácach, ktoré skúmajú patologické deje pri SM, prípadne sa uplatňujú v diagnostike a diferenciálnej diagnostike.
Magnetic resonance (MR) imaging started to be in exacting diagnostic process of multiple scleroris (MS) an important supporting examination method that in 2001 was included into diagnostic criteria (McDonald criteria SM 2001). Following these criteria passed a modification in 2005 and 2010 with an aim to increase their sensitivity at preserving their specificity. MR is at present the most used biomarker in the process of diagnosis, at determination of prognosis and monitoring of disease progression, using conventional and non conventional techniques. Into conventional techniques belong T1 weighted images without or with administration of a contrast medium, T2 weighted images (T2vo) from which postprocessing at using of soft cuttings, the volume of lesions can be determined (e. g. lesion load) for watching of inflammation or at neurodegeneration turn, at patient we can measure the brain atrophy. The non conventional techniques are exercised in experimental works, that examine the pathologic process in MS eventually are applied in diagnosis and differential diagnosis.
... image contrast -- Signal suppression techniques -- Artifacts -- Motion artifact reduction techniques -- MR ... ... angiography -- Advanced imaging applications -- MR spectroscopy -- Instrumentation -- Contrast agents ... ... 13.1 Additional concepts, 162 -- 13.2 Localization techniques, 167 -- 13.3 Spectral analysis and postprocessing ... ... -- 16.5 Contrast media, 199 -- 17 Clinical applications, 200 -- 17.1 General principles of clinical MR ...
Fifth edition xii, 232 stran : ilustrace, tabulky ; 25 cm
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- radiologie, nukleární medicína a zobrazovací metody
- NLK Publikační typ
- kolektivní monografie
For years, the right ventricle (RV) has been deemed 'unnecessary', as shown by procedures such as Fontan surgery. More recently, right ventricular dysfunction has been recognized as a prognostic factor in many cardiovascular diseases. Supported by advances in echocardiography and MRI, assessment of right ventricular function and morphology has gained interest. The goal of this review is to offer a current clinical perspective on right ventricular function as assessed by MRI. RECENT FINDINGS: MRI has progressed towards a fast and reliable technique for assessing right ventricular morphology, volumes and function. Strain-encoded techniques and single breath-hold four-dimensional acquisition techniques are promising, but need to be confirmed in patient studies. Continuous improvement in postprocessing software has further reduced analysis time and effort. SUMMARY: Our understanding of right ventricular behavior even in complex heart disease has taken substantial benefit from modern cardiac MRI techniques. MRI imaging of the RV is patient-tailored, integrating right ventricular volumetric and functional analysis in a comprehensive approach, including assessment of cardiac morphology, myocardial tissue characteristics, flow patterns and great vessel anatomy. This approach provides the clinician a complete view, not only of the RV as such, but also of the RV being an essential part of the cardiopulmonary system.
- MeSH
- funkce pravé komory srdeční fyziologie MeSH
- kardiovaskulární nemoci diagnóza MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Cílem článku je seznámit čtenáře s výhodami a nevýhodami sekvence 4D Flow. Vyšetření touto sekvencí umožňuje retrospektivně zjistit průtok a jiné parametry toku v objemu zájmu. Je ovšem náročné jak z hlediska času, tak následného zpracování dat. Pro vysokou cenu komerčních programů může být pro uživatele nutné vytvořit si vlastní nástroje zpracování dat. Komerční programy poskytují omezené nástroje segmentace, ale naopak zvládají všechny základní korekce a nabízí množství funkcionalit. Přes svůj velký potenciál má sekvence svá omezení, zejména je to nízké prostorové rozlišení a dlouhá doba akvizice.
The goal of this paper is to inform about the 4D Flow sequence, its advantages and disadvantages. 4D Flow examination allows to assess flow rate and other flow parameters in the volume of interest retrospectively. However, it is expensive in terms of time and postprocessing. An in-house software may be necessary, as commercial programs remain costly. They offer a number of functionalities and data corrections. Their segmentations tools, however, remain relatively limited. Low spatial resolution and long data acquisition are the primary limitations of the sequence
- Klíčová slova
- 4D Flow,
- MeSH
- automatizované zpracování dat * metody MeSH
- diagnostické techniky kardiovaskulární přístrojové vybavení MeSH
- lidé MeSH
- magnetická rezonanční tomografie * metody MeSH
- reologie krve MeSH
- software MeSH
- vizualizace dat MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
OBJECTIVE: The purpose of this work was to optimize the acquisition of diffusion-weighted (DW) single-refocused spin-echo (srSE) data without intrinsic eddy-current compensation (ECC) for an improved performance of ECC postprocessing. The rationale is that srSE sequences without ECC may yield shorter echo times (TE) and thus higher signal-to-noise ratios (SNR) than srSE or twice-refocused spin-echo (trSE) schemes with intrinsic ECC. MATERIALS AND METHODS: The proposed method employs dummy scans with DW gradients to drive eddy currents into a steady state before data acquisition. Parameters of the ECC postprocessing algorithm were also optimized. Simulations were performed to obtain minimum TE values for the proposed sequence and sequences with intrinsic ECC. Experimentally, the proposed method was compared with standard DW-trSE imaging, both in vitro and in vivo. RESULTS: Simulations showed substantially shorter TE for the proposed method than for methods with intrinsic ECC when using shortened echo readouts. Data of the proposed method showed a marked increase in SNR. A dummy scan duration of at least 1.5 s improved performance of the ECC postprocessing algorithm. CONCLUSION: Changes proposed for the DW-srSE sequence and for the parameter setting of the postprocessing ECC algorithm considerably reduced eddy-current artifacts and provided a higher SNR.
- MeSH
- algoritmy MeSH
- artefakty MeSH
- difuzní magnetická rezonance * MeSH
- dospělí MeSH
- echoplanární zobrazování * MeSH
- fantomy radiodiagnostické MeSH
- lidé MeSH
- mladý dospělý MeSH
- mozek diagnostické zobrazování MeSH
- počítačová simulace MeSH
- počítačové zpracování obrazu * MeSH
- poměr signál - šum MeSH
- zdraví dobrovolníci pro lékařské studie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Neuroimaging investigations are fundamental in the diagnosis of patients with epilepsy. The International League Against Epilepsy (ILAE) harmonized neuroimaging of epilepsy structural sequences (HARNESS-MRI) protocol was intended as a generalizable structural MRI protocol. The European Reference Network for Rare and Complex Epilepsies, EpiCARE, includes 50 centers, across 26 countries, with expertise in epilepsy. We investigated adherence to the HARNESS-MRI protocol across EpiCARE. A survey on the clinical use of imaging and postprocessing methods in epilepsy patients was distributed among the centers. A descriptive analysis was performed, and results were compared to existing guidelines, as well as a previous survey in 2016. 79% of centers were adhering to the HARNESS-MRI protocol in all epilepsy patients. All centers were acquiring 3D T1-weighted sequences, 90% were acquiring 3D FLAIR and 87% were acquiring high in-plane 2D coronal T2 MRI sequences in all epilepsy patients. In comparison, in 2016, only 50% of centers were following MRI recommendations at the time. Across European expert epilepsy centers, there has been increased harmonization of MRI sequences since the introduction of the HARNESS-MRI protocol. This standardization supports optimal radiological review at individual centers as well as enabling harmonization of multicenter datasets for research. PLAIN LANGUAGE SUMMARY: Neuroimaging investigations are a fundamental component of epilepsy diagnosis. The International League Against Epilepsy (ILAE) has created guidelines about what MRI images to obtain in all epilepsy patients. In this study, we assessed the adherence of expert European epilepsy centers to these guidelines and found that 79% are acquiring the minimum set of MRI scans in all epilepsy patients. Standardization of MRI imaging serves to improve epilepsy diagnosis across Europe.
- MeSH
- dodržování směrnic MeSH
- epilepsie * diagnostické zobrazování MeSH
- lidé MeSH
- magnetická rezonanční tomografie * normy metody MeSH
- mozek * diagnostické zobrazování MeSH
- neurozobrazování * normy metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
- Geografické názvy
- Evropa MeSH