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Arterial spin labeling (ASL) je neinvazivní metoda MR využívaná k zobrazení mozkové perfuze. S rostoucími obavami týkajícími se používání kontrastních látek obsahujících gadolinium a zároveň významnými technickými pokroky v implementaci ASL se tato metoda stává středem zájmu různých diagnostických aplikací. V přehledovém článku se zaměřujeme na seznámení čtenářů se základy implementace sekvence ASL v neuroradiologii, diskutujeme optimální parametry skenování pro dosažení nejlepší kvality a přesnosti interpretace dat a poskytujeme přehled diagnostických aplikací v oblastech cerebrovaskulárních onemocnění, neuroonkologie, epilepsie a neurodegenerace. Kromě toho představujeme ukázkové radiologické případy a komentujeme potenciální budoucí vývoj neinvazivních ASL metod.
Arterial spin labeling (ASL) is a non-invasive MRI method used to image cerebral perfusion. Given increasing concerns regarding the use of gadolinium-based contrast agents and significant technical advancements in ASL implementation, the method is gaining attention in various diagnostic applications. This review article aims to familiarize readers with the fundamentals of ASL sequence implementation in neuroradiology, discuss optimal scanning parameters for achieving the highest quality and accuracy in data interpretation, and provide an overview of its diagnostic applications in the areas of cerebrovascular diseases, neuro-oncology, epilepsy, and neurodegeneration. Furthermore, we present illustrative radiological cases and explore the potential future developments of non-invasive ASL techniques.
- MeSH
- arteriae cerebrales diagnostické zobrazování MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- mozková angiografie MeSH
- mozkový krevní oběh MeSH
- neurozobrazování * metody MeSH
- perfuzní zobrazování * metody MeSH
- spinové značení MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
- směrnice pro lékařskou praxi 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.
List of changes: On the basis of author's request the publisher of Physiological Research decided to change the license of the article to CC BY license.
- Publikační typ
- časopisecké články MeSH
Epilepsie postihuje asi 0,5–1,5 % populace, z čehož přibližně 30 % pacientů vykazuje farmakorezistenci. Význam MR v diagnostice spočívá zejména v odhalení strukturální etiologie onemocnění, zhodnocení prognózy pacienta a limitovaně i v plánování odpovídající léčby. Navzdory technologickému pokroku v přístrojovém a technickém vybavení zdravotnických pracovišť panuje velká nejednotnost v oblasti protokolů MR využívaných ke strukturálnímu zobrazení mozku u pacientů s epilepsií. Cílem našeho sdělení je doporučení standardizovaného MR protokolu strukturálního zobrazení mozku u pacientů s epilepsií, které vychází ze současných mezinárodních doporučení. Jeho široká implementace umožní v České republice nastavit jednotnou platformu neurozobrazení v těchto indikacích.
Epilepsy affects about 0.5-1.5% of the population, of which approximately 30% of patients are drug-resistant. The importance of MRI in diagnosis lies mainly in the detection of structural etiology of the disease, assessing the patient‘s prognosis and, to a limited extent, planning appropriate treatment. Despite technological advances and technical equipment in medical centers, there is a considerable inconsistency in the MRI protocols used for structural brain imaging in patients with epilepsy. We aim to recommend a standardized MR structural brain imaging protocol for patients with epilepsy based on current international recommendations. Its widespread implementation will enable the establishment of a unified neuroimaging platform in the Czech Republic for these indications.
- Klíčová slova
- strukturální zobrazení mozku,
- MeSH
- epilepsie * diagnostické zobrazování MeSH
- lidé MeSH
- magnetická rezonanční tomografie metody MeSH
- neurozobrazování metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Disruption of the blood-brain barrier (BBB) is a key feature of various brain disorders. To assess its integrity a parametrization of dynamic magnetic resonance imaging (DCE MRI) with a contrast agent (CA) is broadly used. Parametrization can be done quantitatively or semi-quantitatively. Quantitative methods directly describe BBB permeability but exhibit several drawbacks such as high computation demands, reproducibility issues, or low robustness. Semi-quantitative methods are fast to compute, simply mathematically described, and robust, however, they do not describe the status of BBB directly but only as a variation of CA concentration in measured tissue. Our goal was to elucidate differences between five semi-quantitative parameters: maximal intensity (Imax), normalized permeability index (NPI), and difference in DCE values between three timepoints: baseline, 5 min, and 15 min (delta5-0, delta15-0, delta15-5) and two quantitative parameters: transfer constant (Ktrans) and an extravascular fraction (Ve). For the purpose of comparison, we analyzed DCE data of four patients 12-15 days after the stroke with visible CA enhancement. Calculated parameters showed abnormalities spatially corresponding with the ischemic lesion, however, findings in individual parameters morphometrically differed. Ktrans and Ve were highly correlated. Delta5-0 and delta15-0 were prominent in regions with rapid CA enhancement and highly correlated with Ktrans. Abnormalities in delta15-5 and NPI were more homogenous with less variable values, smoother borders, and less detail than Ktrans. Moreover, only delta15-5 and NPI were able to distinguish vessels from extravascular space. Our comparison provides important knowledge for understanding and interpreting parameters derived from DCE MRI by both quantitative and semi-quantitative methods.
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are widely used for drug safety and efficacy testing with various techniques, including high content imaging (HCI). Upon drug treatment, a significant number of hiPSC-CMs grown in regular 96-well plates coated with fibronectin detached from the bottom of the plate, complicating data acquisition. Several cell culture configurations were tested to improve cell adherence, and the effects of these configurations on total cell number, separation of feature values between the negative (DMSO 0.1%) and positive (antimycin, staurosporine) controls, scale of feature value differences, and data variability were statistically calculated. hiPSC-CMs were plated on fibronectin- (in "blanket" configuration) or MaxGel- (in "sandwich" configuration) coated plates and covered with a layer of either HydroMatrix or MaxGel 2, 7, or 11d after plating. After a total of 14d in culture, cells were treated with compounds, labeled with four fluorescent dyes (Hoechst, TMRM, NucView, and RedDot), and imaged with GE INCell2000. Based on the statistical parameters calculated, the MaxGel 25% 7d "sandwich" was superior to all other tested conditions when the cells were treated with 0.3 μM antimycin for 2 h and test compounds 10 μM crizotinib and 30 μM amiodarone for 48 h. For staurosporine treatment, the best culturing condition varied between MaxGel "sandwich" systems, depending on which parameters were under consideration. Thus, cell culturing conditions can significantly affect the ability of high content imaging to detect changes in cellular features during compound treatment and should be thoroughly evaluated before committing to compound testing.
- Publikační typ
- časopisecké články MeSH
