PURPOSE: Water removal is one of the computational bottlenecks in the processing of high-resolution MRSI data. The purpose of this work is to propose an approach to reduce the computing time required for water removal in large MRS data. METHODS: In this work, we describe a singular value decomposition-based approach that uses the partial position-time separability and the time-domain linear predictability of MRSI data to reduce the computational time required for water removal. Our approach arranges MRS signals in a Casorati matrix form, applies low-rank approximations utilizing singular value decomposition, removes residual water from the most prominent left-singular vectors, and finally reconstructs the water-free matrix using the processed left-singular vectors. RESULTS: We have demonstrated the effectiveness of our proposed algorithm for water removal using both simulated and in vivo data. The proposed algorithm encompasses a pip-installable tool ( https://pypi.org/project/CSVD/), available on GitHub ( https://github.com/amirshamaei/CSVD), empowering researchers to use it in future studies. Additionally, to further promote transparency and reproducibility, we provide comprehensive code for result replication. CONCLUSIONS: The findings of this study suggest that the proposed method is a promising alternative to existing water removal methods due to its low processing time and good performance in removing water signals.

• Klíčová slova
• MR spectroscopic imaging, functional MRS, low-rank approximations, water removal, water suppression,
• MeSH
• algoritmy MeSH
• magnetická rezonanční spektroskopie MeSH
• magnetická rezonanční tomografie * metody   MeSH
• reprodukovatelnost výsledků MeSH
• voda * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• voda * MeSH

UNLABELLED: The purpose of this article is to summarize some general information about the most common types of cardio-myopathies with an emphasis on a use of cardiac magnetic resonance imaging (CMR) in its diagnosis. Although characteristic CMR findings of the cardiomyopathy are generally revealed, the establishing of a clear diagnosis could be difficult. The assessment of structural myocardial abnormalities allows determination of the degree of changes in the myocardium and the prognosis of the disease. The wide range of information about the heart structure and function is feasible to achieve due to advanced techniques of magnetic resonance imaging and the ima-ging is not limited by acoustic windows as it is in case of echocardiography. The role of CMR in diagnostics of the cardiomyopathies tends to be increasingly important, cardiologists increasingly favour this examination and it is consequently becoming a standard part of a diagnostic algorithm. KEY WORDS: amyloidosis - cardiac magnetic resonance - cardiomyopathy - myocardial hypertrophy.

• MeSH
• kardiomyopatie diagnostické zobrazování   patologie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie * MeSH
• myokard patologie   MeSH
• srdce diagnostické zobrazování   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Magnetic resonance imaging (MRI) relies on appropriate contrast agents, especially for visualizing transplanted cells within host tissue. In recent years, compounds containing fluorine-19 have gained significant attention as MRI probe, particularly in dual 1H/19F-MR imaging. However, various factors affecting probe sensitivity, such as fluorine content and the equivalency of fluorine atoms, must be considered. In this study, we synthesized fluorinated micelles with adjustable surface positive charge density and investigated their physicochemical properties and MRI efficacy in phantoms and labeled cells. While the micelles exhibited clear signals in 19F-MR spectra and imaging, the concentrations required for MRI visualization of labeled cells were relatively high, adversely affecting cell viability. Despite their favourable physicochemical properties, achieving higher labeling rates without compromising cell viability during labeling remains a challenge for potential in vivo applications.

• Klíčová slova
• 19F magnetic resonance imaging, 19F magnetic resonance spectroscopy, Cell labeling, Fluorinated micelles,
• MeSH
• barvení a značení metody   MeSH
• fantomy radiodiagnostické MeSH
• fluor chemie   MeSH
• halogenace MeSH
• kationty * chemie   MeSH
• kontrastní látky chemie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• micely * MeSH
• myši MeSH
• viabilita buněk * účinky léků   MeSH
• zobrazování fluorovou magnetickou rezonancí metody   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fluor MeSH
• kationty * MeSH
• kontrastní látky MeSH
• micely * MeSH

An illustrated case with Morton's metatarsalgia is presented. MR imaging was helpful for determining the presence, location and magnitude of intermetatarsal neuroma. Moreover, it had a large influence on the differential diagnostic thinking because many disorders may produce forefoot complaints mimicking Morton's metatarsalgia.

• MeSH
• diferenciální diagnóza MeSH
• dospělí MeSH
• lidé MeSH
• magnetická rezonanční tomografie * MeSH
• metatarzalgie diagnóza   MeSH
• přednoží člověka patologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

OBJECTIVEThe aim of this study was to compare 3 different methods to assess the geometrical distortion of two 1.5-T and one 3-T magnetic resonance (MR) scanners and to evaluate co-registration accuracy. The overall uncertainty of each particular method was also evaluated.METHODSThree different MR phantoms were used: 2 commercial CIRS skull phantoms and PTGR known target phantom and 1 custom cylindrical Perspex phantom made in-house. All phantoms were fixed in the Leksell stereotactic frame and examined by a Siemens Somatom CT unit, two 1.5-T Siemens (Avanto and Symphony) MRI systems, and one 3-T Siemens (Skyra) MRI system. The images were evaluated using Leksell GammaPlan software, and geometrical deviation of the selected points from the reference values were determined. The deviations were further investigated for both definitions including fiducial-based and co-registration-based in the case of the CIRS phantom images. The same co-registration accuracy assessment was also performed for a clinical case. Patient stereotactic imaging was done on 3-T Skyra, 1.5-T Avanto, and CT scanners.RESULTSThe accuracy of the CT scanner was determined as 0.10, 0.30, and 0.30 mm for X, Y, and Z coordinates, respectively. The total estimated uncertainty in distortion measurement in one coordinate was determined to be 0.32 mm and 0.14 mm, respectively, for methods using and not using CT as reference imaging. Slightly more significant distortions were observed when using the 3-T than either 1.5-T MR units. However, all scanners were comparable within the estimated measurement error. Observed deviation/distortion for individual X, Y, and Z stereotactic coordinates was typically within 0.50 mm for all 3 scanners and all 3 measurement methods employed. The total radial deviation/distortion was typically within 1.00 mm. Maximum total radial distortion was observed when the CIRS phantom was used; 1.08 ± 0.49 mm, 1.15 ± 0.48 mm, and 1.35 ± 0.49 mm for Symphony, Avanto, and Skyra, respectively. The co-registration process improved image stereotactic definition in a clinical case in which fiducial-based stereotactic definition was not accurate; this was demonstrated for 3-T stereotactic imaging in this study. The best results were shown for 3-T MR image co-registration with CT images improving image stereotactic definition by about 0.50 mm. The results obtained with patient data provided a similar trend of improvement in stereotactic definition by co-registration.CONCLUSIONSAll 3 methods/phantoms used were evaluated as satisfactory for the image distortion measurement. The method using the PTGR phantom had the lowest uncertainty as no reference CT imaging was needed. Image co-registration can improve stereotactic image definition when fiducial-based definition is not accurate.

• Klíčová slova
• CT = computed tomography, MRI = magnetic resonance imaging, PET = positron emission tomography, image co-registration, phantom measurement, stereotactic MR imaging, stereotactic methods, stereotactic radiosurgery,
• MeSH
• artefakty MeSH
• fantomy radiodiagnostické * MeSH
• lebka MeSH
• lidé MeSH
• magnetická rezonanční tomografie přístrojové vybavení   metody   MeSH
• modely anatomické MeSH
• počítačová rentgenová tomografie MeSH
• počítačové zpracování obrazu MeSH
• reprodukovatelnost výsledků MeSH
• software MeSH
• stereotaktické techniky * přístrojové vybavení   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH

PURPOSE: Combining specific and quantitative F-19 magnetic resonance imaging (MRI) with sensitive and convenient optical imaging provides complementary information about the distribution and viability of transplanted pancreatic islet grafts. In this study, pancreatic islets (PIs) were labeled with positively charged multimodal nanoparticles based on poly(lactic-co-glycolic acid) (PLGA-NPs) with encapsulated perfluoro-15-crown-5-ether and the near-infrared fluorescent dye indocyanine green. PROCEDURES: One thousand and three thousand bioluminescent PIs were transplanted into subcutaneous artificial scaffolds, which served as an alternative transplant site. The grafts were monitored using in vivo F-19 MR, fluorescence, and bioluminescence imaging in healthy rats for 2 weeks. RESULTS: Transplanted PIs were unambiguously localized in the scaffolds by F-19 MRI throughout the whole experiment. Fluorescence was detected in the first 4 days after transplantation only. Importantly, in vivo bioluminescence correlated with the F-19 MRI signal. CONCLUSIONS: We developed a trimodal imaging platform for in vivo examination of transplanted PIs. Fluorescence imaging revealed instability of the fluorescent dye and its limited applicability for longitudinal in vivo studies. A correlation between the bioluminescence signal and the F-19 MRI signal indicated the fast clearance of PLGA-NPs from the transplantation site after cell death, which addresses a major issue with intracellular imaging labels. Therefore, the proposed PLGA-NP platform is reliable for reflecting the status of transplanted PIs in vivo.

• Klíčová slova
• F-19 magnetic resonance imaging, Nanoparticles, Optical imaging, Pancreatic islets, Transplantation,
• MeSH
• endocytóza MeSH
• fluor chemie   MeSH
• fluorescence MeSH
• Langerhansovy ostrůvky diagnostické zobrazování   MeSH
• luminiscenční měření * MeSH
• magnetická rezonanční tomografie * MeSH
• modely u zvířat MeSH
• molekulární zobrazování * MeSH
• potkani inbrední LEW MeSH
• potkani transgenní MeSH
• přežití tkáně MeSH
• tkáňové podpůrné struktury chemie   MeSH
• transplantace Langerhansových ostrůvků * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fluor MeSH

The aim of this article is to describe the feasibility of performing intraoperative MR imaging in patients with spinal cord lesions and the potential value of this technique. The authors report a case involving a 28-year-old man who presented with chronic cervical pain and pain along the ulnar side of the forearms during neck flexion. Findings on clinical examination were normal, but MR imaging revealed a multicystic cervical spinal cord lesion. Surgery was undertaken to open the cysts, evacuate old blood, and search for pathological tissue. Intraoperative MR imaging showed that the caudal cyst was not opened, and surgery was therefore continued. The caudal cyst was fenestrated and a suspected small cavernous malformation was removed. Electrophysiological monitoring was performed both before and after the intraoperative MR imaging. The use of intraoperative MR imaging changed the strategy of the procedure and helped the surgeon to safely enter all the cysts in the cervical cord.

• MeSH
• dospělí MeSH
• krční obratle patologie   chirurgie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie * MeSH
• mícha patologie   chirurgie   MeSH
• nemoci míchy patologie   chirurgie   MeSH
• peroperační monitorování metody   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH

We describe a technique for simulation and correction of the effects of an arbitrary distribution of undesired components of the static and gradient magnetic fields. This technique is applicable to direct Fourier NMR imaging. The mathematical basis and details of this technique are fully described. Computer simulation demonstrates the effectiveness of this method.

• MeSH
• Fourierova analýza MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• mozek anatomie a histologie   MeSH
• počítačová simulace * MeSH
• počítačové zpracování obrazu * MeSH
• ruka anatomie a histologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

We studied 33 patients with astrocytomas of different grades (68 examinations) by magnetic resonance imaging (MRI) and proton MR spectroscopy ((1)H-MRS). We found that in 80% of the spectra, the presence of signals in the area of 0.8-1.5 ppm, assigned to lipids/lactate in (1)H-MR spectra, correlated with signal enhancement after Gd-DTPA administration. We suggest that visibility of lipid/lactate signals could be due to blood-brain barrier damage, which is characterized by contrast agent enhancement.

• MeSH
• astrocytom diagnóza   metabolismus   MeSH
• diethylentriaminpentaacetát gadolinia * MeSH
• dítě MeSH
• kojenec MeSH
• kontrastní látky * MeSH
• kyselina mléčná metabolismus   MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie * MeSH
• magnetická rezonanční tomografie * MeSH
• metabolismus lipidů MeSH
• mladiství MeSH
• mozek metabolismus   patologie   MeSH
• nádory mozku diagnóza   metabolismus   MeSH
• předškolní dítě MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• předškolní dítě MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• diethylentriaminpentaacetát gadolinia * MeSH
• kontrastní látky * MeSH
• kyselina mléčná MeSH

OBJECTIVES: A prospective quantitative MR study of brain tumours was performed to show the potential of combining different MR techniques to distinguish various disease processes in routine clinical practice. METHODS: Twenty-three patients with various intracranial tumours before treatment (diagnosis confirmed by a biopsy) and 59 healthy subjects were examined on a 3-T system by conventional MR imaging, 1H spectroscopic imaging, diffusion tensor imaging and T2 relaxometry. Metabolic concentrations and their ratios, T2 relaxation times and mean diffusivities were calculated and correlated on a pixel-by-pixel basis and compared to control data. RESULTS: Different tumour types and different localisations revealed specific patterns of correlations between metabolic concentrations and mean diffusivity or T2 relaxation times. The patterns distinguish given tissue states in the examined area: healthy tissue, tissue infiltrated by tumour, active tumour, oedema infiltrated by tumour, oedema, etc. This method is able to describe the complexity of a highly heterogeneous tissue in the tumour and its vicinity, and determines crucial parameters for tissue differentiation. CONCLUSIONS: A combination of different MR parameters on a pixel-by-pixel basis in individual patients enables better identification of the tumour type, direction of proliferation and assessment of the tumour extension. KEY POINTS: • Magnetic resonance offers many different methods of examining the brain. • A combination of quantitative MR parameters helps distinguish different brain lesions • Different tumour types revealed specific correlation patterns amongst different MR parameters • The correlation patterns reflect highly heterogeneous complex tissue within tumours.

• MeSH
• biopsie metody   MeSH
• difuze MeSH
• dospělí MeSH
• edém patologie   MeSH
• gliom MeSH
• lidé středního věku MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie metody   MeSH
• magnetická rezonanční tomografie metody   MeSH
• mapování mozku metody   MeSH
• mozek patologie   MeSH
• nádory mozku diagnóza   patologie   MeSH
• počítačové zpracování obrazu MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• zobrazování difuzních tenzorů metody   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH