Dynamická kontrastní ultrasonografie (CEUS - contrast-enhanced ultrasound) je poměrně novou zobrazovací modalitou, která umožňuje hodnotit průběh opacifikace cév a tkání, a to nejen v dopplerovském, ale i ve dvourozměrném ultrasonografickém obrazu. Největšího uplatnění u dětí dosud metoda nalezla v diagnostice ložiskového postižení jater a při hodnocení poúrazových změn parenchymatózních orgánů dutiny břišní. Autoři prezentují své dosavadní zkušenosti s využitím metody při diagnostice fokálních lézí jater u dětí.

Dynamic contrast enhanced ultrasound (CEUS) is a novel imaging method that enables assessment of blood vessels and tissues. Among the methods used for CEUS are Doppler and double space ultrasound imaging. In children, this method can be used to diagnose focal liver lesions and to assess traumatic lesions of the abdomen. The authors demonstrate their contemporary experience of using this method to diagnose focal liver lesions in children.

• Klíčová slova
• kontrastní ultrasonografie, hemagiom,
• MeSH
• dítě MeSH
• játra * diagnostické zobrazování   MeSH
• kontrastní látky MeSH
• lidé MeSH
• nemoci jater diagnostické zobrazování   MeSH
• ultrasonografie * metody   MeSH
• vylepšení obrazu MeSH
• Check Tag
• dítě MeSH
• lidé MeSH

OBJECTIVE: An extension of single- and multi-channel blind deconvolution is presented to improve the estimation of the arterial input function (AIF) in quantitative dynamic contrast enhanced magnetic resonance imaging (DCE-MRI). METHODS: The Lucy-Richardson expectation-maximization algorithm is used to obtain estimates of the AIF and the tissue residue function (TRF). In the first part of the algorithm, nonparametric estimates of the AIF and TRF are obtained. In the second part, the decaying part of the AIF is approximated by three decaying exponential functions with the same delay, giving an almost noise free semi-parametric AIF. Simultaneously, the TRF is approximated using the adiabatic approximation of the Johnson-Wilson (aaJW) pharmacokinetic model. RESULTS: In simulations and tests on real data, use of this AIF gave perfusion values close to those obtained with the corresponding previously published nonparametric AIF, and are more noise robust. CONCLUSION: When used subsequently in voxelwise perfusion analysis, these semi-parametric AIFs should give more correct perfusion analysis maps less affected by recording noise than the corresponding nonparametric AIFs, and AIFs obtained from arteries. SIGNIFICANCE: This paper presents a method to increase the noise robustness in the estimation of the perfusion parameter values in DCE-MRI.

• MeSH
• algoritmy MeSH
• arterie patologie   MeSH
• kontrastní látky chemie   farmakokinetika   MeSH
• magnetická rezonanční tomografie * MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• perfuze MeSH
• počítačová simulace MeSH
• počítačové zpracování obrazu * MeSH
• reprodukovatelnost výsledků MeSH
• vylepšení obrazu * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The paper deals with modeling the liver perfusion intended to improve quantitative analysis of the tissue scans provided by the contrast-enhanced computed tomography (CT). For this purpose, we developed a model of dynamic transport of the contrast fluid through the hierarchies of the perfusion trees. Conceptually, computed time-space distributions of the so-called tissue density can be compared with the measured data obtained from CT; such a modeling feedback can be used for model parameter identification. The blood flow is characterized at several scales for which different models are used. Flows in upper hierarchies represented by larger branching vessels are described using simple 1D models based on the Bernoulli equation extended by correction terms to respect the local pressure losses. To describe flows in smaller vessels and in the tissue parenchyma, we propose a 3D continuum model of porous medium defined in terms of hierarchically matched compartments characterized by hydraulic permeabilities. The 1D models corresponding to the portal and hepatic veins are coupled with the 3D model through point sources, or sinks. The contrast fluid saturation is governed by transport equations adapted for the 1D and 3D flow models. The complex perfusion model has been implemented using the finite element and finite volume methods. We report numerical examples computed for anatomically relevant geometries of the liver organ and of the principal vascular trees. The simulated tissue density corresponding to the CT examination output reflects a pathology modeled as a localized permeability deficiency.

• MeSH
• analýza metodou konečných prvků MeSH
• biologické modely MeSH
• jaterní oběh * fyziologie   MeSH
• játra krevní zásobení   diagnostické zobrazování   MeSH
• kontrastní látky farmakokinetika   MeSH
• lidé MeSH
• matematické pojmy MeSH
• počítačová rentgenová tomografie statistika a číselné údaje   MeSH
• počítačová simulace MeSH
• poréznost MeSH
• vylepšení rentgenového snímku metody   MeSH
• zobrazování trojrozměrné statistika a číselné údaje   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Aims: To evaluate the role of dynamic contrast-enhanced magnetic resonance imaging (MRI) in the diagnosisof BI-RADS-5 type of microcalcifi cations of the breast, to compare the size of the microcalcifi cation lesions usingmammography (MG) and MRI, and to determine the value of MRI in surgery for microcalcifi cations. The study alsodetermines the morphology of microcalcifi cation lesions, assesses kinetic curves and compare MRI features of ductalcarcinoma in situ (DCIS) for diff erent histopathological grades. Methods: Our group consisted of 32 patients with mammographically detected BI-RADS 5 microcalcifi cations.The MRI was done in this group of women which was later followed by stereotactic vaccum-assisted biopsy (SVAB).Surgery was performed on all patients with a biopsy that resulted in a diagnosis of breast cancer or atypical ductalhyperplasia (ADH). Results: Of our group of 32 patients, there were 35 mammograhically detected microcalcifi cation lesions, 32 DCIS,one ADH and two benign fi ndings according to the fi nal histology.The microcalcifi cation lesions were larger using MRI than in MG in 10 women. We diagnosed DCIS multifocalityin 6 women and bilateral carcinoma in one woman. As with kinetic curve assessment, we found in 67 % of DCIS arapid rise, 27 % a moderate and in 6 % a slow initial rise. With the pattern of enhancement in the delayed phase, wefound in 30 % of DCIS a washout pattern, 67 % a plateau and in 3 % a persistent pattern. Noted diff erence betweenhigh and low grade DCIS was confi rmed. Conclusions: MRI sensitivity in the detection of DCIS was 94 % in our group of patients and was the sole evidencefor detection of multifocality and bilateral incidence of carcinoma. In 26 % of women the outcome of MRI was themost important for converting breast conserving surgery to mastectomy.

• MeSH
• biopsie metody   využití   MeSH
• duktální karcinom prsu diagnóza   MeSH
• financování organizované MeSH
• histologické techniky metody   využití   MeSH
• hodnotící studie jako téma MeSH
• kalcinóza diagnóza   MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   využití   MeSH
• mamografie metody   využití   MeSH
• nádory prsu diagnóza   MeSH
• počítačové zpracování obrazu metody   využití   MeSH
• senzitivita a specificita MeSH
• statistika jako téma MeSH
• ultrasonografie prsů metody   využití   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH

Cieľ: Kontrastná ultrasonografia (z angl. contrast-enhanced ultrasound – CEUS) predstavuje diagnostickú metódu, ktorá umožňuje dynamické zobrazenie tkaniva v reálnom čase so zaznamenávaním charakteristického vzoru vysycovania ložiska kontrastnou látkou. Cieľom autorov je poukázať na význam tejto zobrazovacej modality v diferenciálnej diagnostike tumorov pečene u novorodeneckých pacientov prostredníctvom dvoch kazuistických prípadov. Metodika: Po intravenóznej aplikácii kontrastnej látky s výlučne intravaskulárnou distribúciou sa v jednotlivých fázach CEUS vyšetrenia zaznamenáva intenzita signálu kontrastnej látky v ložisku pečene a jeho okolí. V priebehu artériovej fázy je hodnotená vaskularizácia ložiska, následne v portálnej a neskorej fáze je možné podrobnejšie hodnotiť dignitu lézie. Výsledky: Dvaja novorodenci s tumoróznym ložiskom pečene podstúpili CEUS vyšetrenie s cieľom bližšej charakterizácie lézie. Na základe CEUS vyšetrenia boli u týchto novorodencov diagnostikované hemangióm a hepatoblastóm. U pacientov sme nezaznamenali nežiadúce účinky v súvislosti s intravenóznym podaním kontrastnej látky. Záver: Podľa našich doterajších skúseností je CEUS vyšetrenie vhodná diagnostická metóda v diferenciálnej diagnostike tumoróznych lézií pečene aj u pacientov v novorodeneckom veku. Realizácia a následná interpretácia výsledkov si však vyžadujú zaškolený zdravotný personál.

Aim: Contrast-enhanced ultrasound (CEUS) is a novel diagnostic method that enables dynamic imaging of tissues in real time with recording characteristic pattern of bearing contrast agent in liver lesion. The aim of the authors is to point out the importance of this imaging modality in the differential diagnosis of liver tumors in newborns through the presentation of two case reports. Methodology: After intravenous application of microbubble contrast agent with exclusively intravascular distribution the signal intensity is recorded in the individual phases of the examination in liver lesion and its surroundings. During the arterial phase the vascularization of the lesion is evaluated, in the portal and late phase is possible to specify the dignity of the liver lesion more precisely. Results: Two newborns with liver tumors underwent CEUS examination with the aim of closer characterization of the lesion. Based on the CEUS in these newborns were diagnosed hemangioma and hepatoblastoma. We did not observe any adverse effects related to the intravenous administration of the contrast agent. Conclusion: According to our expiriences so far is CEUS a suitable diagnostic method in differential diagnosis of liver tumors also at patients of neonatal age. Realization and interpretation of results reguire trained medical staff.

• Klíčová slova
• kontrastní ultrasonografie,
• MeSH
• kontrastní látky MeSH
• lidé MeSH
• nádory jater * diagnostické zobrazování   MeSH
• novorozenec MeSH
• ultrasonografie metody   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• kazuistiky MeSH

PURPOSE: Ktrans$$ {K}^{\mathrm{trans}} $$ has often been proposed as a quantitative imaging biomarker for diagnosis, prognosis, and treatment response assessment for various tumors. None of the many software tools for Ktrans$$ {K}^{\mathrm{trans}} $$ quantification are standardized. The ISMRM Open Science Initiative for Perfusion Imaging-Dynamic Contrast-Enhanced (OSIPI-DCE) challenge was designed to benchmark methods to better help the efforts to standardize Ktrans$$ {K}^{\mathrm{trans}} $$ measurement. METHODS: A framework was created to evaluate Ktrans$$ {K}^{\mathrm{trans}} $$ values produced by DCE-MRI analysis pipelines to enable benchmarking. The perfusion MRI community was invited to apply their pipelines for Ktrans$$ {K}^{\mathrm{trans}} $$ quantification in glioblastoma from clinical and synthetic patients. Submissions were required to include the entrants' Ktrans$$ {K}^{\mathrm{trans}} $$ values, the applied software, and a standard operating procedure. These were evaluated using the proposed OSIPIgold$$ \mathrm{OSIP}{\mathrm{I}}_{\mathrm{gold}} $$ score defined with accuracy, repeatability, and reproducibility components. RESULTS: Across the 10 received submissions, the OSIPIgold$$ \mathrm{OSIP}{\mathrm{I}}_{\mathrm{gold}} $$ score ranged from 28% to 78% with a 59% median. The accuracy, repeatability, and reproducibility scores ranged from 0.54 to 0.92, 0.64 to 0.86, and 0.65 to 1.00, respectively (0-1 = lowest-highest). Manual arterial input function selection markedly affected the reproducibility and showed greater variability in Ktrans$$ {K}^{\mathrm{trans}} $$ analysis than automated methods. Furthermore, provision of a detailed standard operating procedure was critical for higher reproducibility. CONCLUSIONS: This study reports results from the OSIPI-DCE challenge and highlights the high inter-software variability within Ktrans$$ {K}^{\mathrm{trans}} $$ estimation, providing a framework for ongoing benchmarking against the scores presented. Through this challenge, the participating teams were ranked based on the performance of their software tools in the particular setting of this challenge. In a real-world clinical setting, many of these tools may perform differently with different benchmarking methodology.

• MeSH
• algoritmy MeSH
• kontrastní látky * MeSH
• lidé MeSH
• magnetická rezonanční tomografie * metody   MeSH
• reprodukovatelnost výsledků MeSH
• software MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Cíl. Retrospektivní studie srovnává výtěžnost CEUS, CT a MR. Cílem práce bylo stanovit přesnost (úspěšnost) jednotlivých zobrazovacích metod vzhledem k histologickému ověření a zjistit, nakolik jsou jednotlivé metody schopny rozlišit mezi benigním a maligním ložiskem obecně, navrhnout optimální diagnostický algoritmus. Metoda. Retrospektivní hodnocení souboru 62 pacientů mezi roky 2005-2009, kterým byla diagnóza histologický ověřena. US vyšetření byla prováděna na přístroji ATL HDI 5000 režimem pulzní inverze, na IU 22 Phillips režimy pulzní inverze a pulzní modulace. CT na Siemens Somatom plus či Phillips Brilliance 64, v minimálně ve dvou dynamických postkontrastních fázích, MR vyšetření na Phillips Achieva 1,5T, s použitím hepato-specifických kontrastních látek a dynamického postkontrastního čtyřfázového vyšetření. Kromě procentuálního vyjádření přesnosti jednotlivých metod vzhledem k histologickému ověření byly metody hodnoceny také stran senzitivity, specificity, pozitivní a negativní prediktivní hodnoty vzhledem k jejich schopnosti identifikovat maligní ložisko. Výsledky. V přesnosti metody shodnout se s histologickým vyšetřením MR dosahovala shody v 85,7%, CEUS v 82%, CT v 62%. Ve schopnosti identifikovat v játrech maligní ložisko: MR senzitivita 93,8% a specificita 100%, CEUS 91,4% a 92,3% a CT 77,8% a 88,5%. Pozitivní prediktivní hodnoty (PPV): MR100%, CEUS 94% a CT 90%. Negativní (NPV): MR 92 %, CEUS 90 % a CT 74%. Závěr. Hodnoty senzitivity, specificity a úspěšnosti metody kontrastního ultrazvukového vyšetření naměřené na našem souboru korelují s hodnotami uváděnými v literatuře a potvrzují, že tato metoda má své významné místo v diagnostickém algoritmu ložiskových lézí jater.

Aim. Co compare retrospectively study of different imaging modalities (CEUS, CT, MR) and to determine the hit rate of these modalities with regard to histological diagnose and with respect to distinguish between benign and malignant lesion in general, the proposal of optimal diagnostic algorithm of focal liver lesions. Method. Retrospective evaluation of th group of 62 patients examined from 2005 to 2009 with histological evaluation. US examinations were done on ATL HDI 5000 and IU 22 Phillips. CT examinations on Siemens Somatom plus or Phillips Brilliance (64), using dynamic postcontrast examination. MR on Phillips Achieva 1.5 T, using hepatospecific contrast agents and dynamic postcontrast examination in 4 phases. Beyond the hit rate of the modalities with regard to histological diagnose also the sensitivity, specificity, positive predictive values and negative predictive values to distiguish malignant lesion from benign were evaluated. Results. Concerning the histological diagnose, MR has the hit rate of 85.7%, CEUS - 82%, CT - 62%. For differentiation between malignant and benign lesion MR sensitivity was 93,8% and specificity 100%, CEUS 91.4% and 92.3% , CT 77.8% and 88.5%. PPV were 100%, 94% and 90% and NPV 92%, 90% and 74% for MR, CEUS and CT respectively. Conclusion. Our sensitivity, specificity, PPV, NPV and hit rates well correlate with those described in literature, confiming that CEUS is meaningful diagnostic tool in the diagnostic algortithm of focal liver lesions.

• Klíčová slova
• diagnóza diferenciální, játra, ultrazvuk,
• MeSH
• diagnóza MeSH
• diferenciální diagnóza MeSH
• fluorid sírový diagnostické užití   MeSH
• histologické techniky MeSH
• hyperplazie MeSH
• kontrastní látky diagnostické užití   klasifikace   MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   využití   MeSH
• mikrobubliny MeSH
• nádory jater ultrasonografie   MeSH
• nemoci jater ultrasonografie   MeSH
• počítačová rentgenová tomografie metody   využití   MeSH
• proliferace buněk MeSH
• retrospektivní studie MeSH
• senzitivita a specificita MeSH
• statistika jako téma MeSH
• ultrasonografie metody   využití   MeSH
• Check Tag
• lidé MeSH

The temporomandibular joint (TMJ) is typically involved in 45-87% of children with Juvenile Idiopathic Arthritis (JIA). Accurate diagnosis of JIA is difficult as various clinical tests, including MRI, disagree. The purpose of this study is to optimize the methodological aspects of Dynamic Contrast Enhanced (DCE) MRI of the TMJ in children. In this cross-sectional study, including data from 73 JIA affected children, aged 6-15 years, effects of motion correction, sampling rate and parametric modelling on DCE-MRI data is investigated. Consensus among three radiologists determined the regions of interest. Quantitative perfusion parameters were estimated using four perfusion models; the Adiabatic Approximation to Tissue Homogeneity (AATH), Distributed Capillary Adiabatic Tissue Homogeneity (DCATH), Gamma Capillary Transit Time (GCTT) and Two Compartment Exchange (2CXM) models. Effects of motion correction were evaluated by a sum of least squares between corrected raw data and the GCTT model. The effect of systematically down sampling the raw data was tested. The sum of least squares was computed across all pharmacokinetic models. Relative difference perfusion parameters between the left and right TMJ were used for an unsupervised k-means based stratification of the data based on a principal component analysis, as well as for a supervised random forest classification. Diagnostic sensitivity and specificity were computed relative to structural image scorings. Paired sample t-tests, as well as ANOVA tests, were used (significant threshold: p < 0.05) with Tukeys post hoc test. High-level elastic motion correction provides the best least square fit to the GCTT model (percental improvement: 72-84%). A 4 s sampling rate captures more of the potentially disease relevant signal variations. The various parametric models all leave comparable residues (relative standard deviation: 3.4%). In further evaluation of DCE-MRI as a potential diagnostic tool for JIA a high-level elastic motion correction scheme should be adopted, with a sampling rate of at least 4 s. Results suggest that DCE-MRI data can be a valuable part in JIA diagnostics in the TMJ.

• MeSH
• artefakty MeSH
• dítě MeSH
• juvenilní artritida diagnostické zobrazování   MeSH
• lidé MeSH
• magnetická rezonanční tomografie * MeSH
• mladiství MeSH
• počítačové zpracování obrazu * MeSH
• pohyb * MeSH
• předškolní dítě MeSH
• průřezové studie MeSH
• senzitivita a specificita MeSH
• statistické modely * MeSH
• temporomandibulární kloub diagnostické zobrazování   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: The transplantation of islets of Langerhans isolated from one donor pancreas can rarely release a diabetic recipient from insulin injections. The major reason is the destruction of 50%-60% of the transplanted tissue, which proceeds typically within a few hours after the insertion of the islets into the portal vein. Therefore, several groups have focused on development of an artificial site for islet transplantation. The main aim of the present study was to test the efficacy of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to evaluate the blood supply feeding the artificially created cavities for islet transplantation. METHODS: Two rounded devices were implanted: one device subcutaneously and the second one into the greater omentum of each animal. On the day of implantation as well as 1, 3, and 4 weeks later, we quickly injected the vascular specific MR contrast agent Vasovist (0.05 mL/100 g) intravenously. Penetration of the contrast agent was monitored by DCE-MRI. The influence of the contrast agent on the signal intensity observed within selected target areas was calculated with the use of ImageJ software. RESULTS: The penetration of the contrast agent was detected by the increase in signal intensity within implanted devices. The signal increase caused by the contrast compound was normalized to kidney tissue. On day of implantation of the device, no signal due to the contrast agent was detected in all devices. However, over the following weeks, there was an increase in signal detection within the omental device to 34%, 21%, and 14% of that of the kidney. Within the subcutaneously implanted devices there was an increase in signal detection up to 11%, 10%, and 7% of that detected in the kidney. CONCLUSIONS: The optimal time for transplantation of pancreatic islets into our omental device was 1 week after implantation of the scaffold. Also, the blood supply feeding the subcutaneous devices was regarded to be inadequate.

• MeSH
• biokompatibilní materiály MeSH
• časové faktory MeSH
• experimentální diabetes mellitus patologie   MeSH
• gadolinium farmakologie   MeSH
• intravenózní infuze MeSH
• kontrastní látky farmakologie   MeSH
• krysa rodu rattus MeSH
• Langerhansovy ostrůvky cytologie   MeSH
• ledviny metabolismus   MeSH
• magnetická rezonanční tomografie metody   MeSH
• organokovové sloučeniny farmakologie   MeSH
• software MeSH
• tkáňové podpůrné struktury MeSH
• transplantace Langerhansových ostrůvků metody   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem 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.

• MeSH
• hematoencefalická bariéra * diagnostické zobrazování   MeSH
• kontrastní látky MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• nemoci mozku * MeSH
• reprodukovatelnost výsledků MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH