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Disparity of time-contrast curves generated by various types of power injectors used in magnetic resonance imaging

Marcus Doppler, Ewald Moser, Uros Klickovic, Christian Nasel
2020 Scientific Reports  
The profiles of time-contrast (TC) -curves from popular MRI injectors derived at the injection site of the attached tube-line system were compared. Variations of TC-profiles were previously reported to potentially influence image quality in time critical MRI measurements. TC-curves from five injectors obtained during commonly used injection protocols were assessed according to representative quality criteria: (1) correlation strength between a fitted boxcar function and the TC-curve (cBCF) and
more » ... 2) difference between true and expected injection time (dBIT). Additionally, the impact from technical injector properties: pump type, line volume, maximum injection power and type of contrast medium (CM) on the TC-profiles was evaluated. Injectors using a piston-syrinx (PS) mechanism for CM-injection performed significantly better than those working with a peristaltic roller pump (RP) technique. Besides injection mechanism, line filling volume showed a strong influence on the final TC-curves, where larger filling volumes induced worse cBCF- and dBIT-results. Therefore, to achieve an optimal bolus in clinical MRI use of a PS-injector seems recommendable. Besides their pump mechanism, RP-injectors appeared additionally hampered by their high volume line systems, pointing out an unfavourable coinicidence of these technical features in RP-injectors. This should be considered, particularly, in comparative or time-critical MRI-studies.
doi:10.1038/s41598-020-76536-x pmid:33177570 fatcat:bz6jud6g4zgkxkzxtrzejkmkpi

Skeletal muscle MRI differentiates SBMA and ALS and correlates with disease severity [article]

Uros Klickovic, Luca Zampedri, Christopher Sinclair, Stephen Wastling, Karin Trimmel, Robin Howard, Andrea Malaspina, Nikhil Sharma, Katie Sidle, Ahmed Emira, Sachit Shah, Tarek Yousry (+5 others)
2018 biorxiv/medrxiv   pre-print
Objective: To investigate the use of muscle MRI for the differential diagnosis and as a disease progression biomarker for two major forms of motor neuron disorders, spinal bulbar muscular atrophy (SBMA) and amyotrophic lateral sclerosis (ALS). Methods: We applied quantitative 3-point Dixon and semi-quantitative T1-weighted and STIR imaging to bulbar and lower limb muscles and performed clinical and functional assessments in ALS (n=21) and SBMA (n=21) patients, alongside healthy controls (n=16).
more » ... Acquired images were analyzed for the presence of fat infiltration or edema as well as specific patterns of muscle involvement. Quantitative MRI measurements were correlated with clinical parameters of disease severity in ALS and SBMA. Results: Quantitative imaging revealed significant fat infiltration in bulbar (p<0.001) and limb muscles in SBMA compared to controls (thigh: p<0.001; calf: p=0.001), identifying a characteristic pattern of muscle involvement. In ALS, semi-quantitative STIR imaging detected marked hyperintensities in lower limb muscles, distinguishing ALS from SBMA and controls. Lastly, MRI measurements correlated significantly with clinical scales of disease severity in both ALS and SBMA. Conclusions: Our findings show that muscle MRI differentiates between SBMA and ALS and correlates with disease severity, supporting its use as a diagnostic tool and biomarker for disease progression. This highlights the clinical utility of muscle MRI in motor neuron disorders and contributes to establish objective outcome measures, which is crucial for the development of new drugs.
doi:10.1101/486910 fatcat:4abntj77xrcwni6rqaoqtknuxy

Human Pharmacokinetics of High Dose Oral Curcumin and Its Effect on Heme Oxygenase-1 Expression in Healthy Male Subjects

Uros Klickovic, Daniel Doberer, Ghazaleh Gouya, Stefan Aschauer, Stefan Weisshaar, Angela Storka, Martin Bilban, Michael Wolzt
2014 BioMed Research International  
Authors' Contribution Uros Klickovic and Daniel Doberer contributed equally to this study and should be considered cofirst authors.  ... 
doi:10.1155/2014/458592 pmid:24592391 pmcid:PMC3925623 fatcat:qaxz2y2whrc2temgljxypwvqpy

Skeletal muscle MRI differentiates SBMA and ALS and correlates with disease severity

Uros Klickovic, Luca Zampedri, Christopher D.J. Sinclair, Stephen J. Wastling, Karin Trimmel, Robin S. Howard, Andrea Malaspina, Nikhil Sharma, Katie Sidle, Ahmed Emira, Sachit Shah, Tarek A. Yousry (+5 others)
2019 Neurology  
To investigate the use of muscle MRI for the differential diagnosis and as a disease progression biomarker for 2 major forms of motor neuron disorders: spinal bulbar muscular atrophy (SBMA) and amyotrophic lateral sclerosis (ALS).
doi:10.1212/wnl.0000000000008009 pmid:31391248 pmcid:PMC6745729 fatcat:stqmkny7efbvvj7cgg63jab634

A Quantitative Comparison of Clinically Employed Parameters in the Assessment of Acute Cerebral Ischemia Using Dynamic Susceptibility Contrast Magnetic Resonance Imaging

Christian Nasel, Uros Klickovic, Heike-Marie Kührer, Kersten Villringer, Jochen B. Fiebach, Arno Villringer, Ewald Moser
2019 Frontiers in Physiology  
Purpose: Perfusion magnetic resonance imaging (P-MRI) is part of the mismatch concept employed for therapy decisions in acute ischemic stroke. Using dynamic susceptibility contrast (DSC) MRI the time-to-maximum (Tmax) parameter is quite popular, but its inconsistently defined computation, arterial input function (AIF) selection, and the applied deconvolution method may introduce bias into the assessment. Alternatively, parameter free methods, namely, standardized time-to-peak (stdTTP),
more » ... and standardized-zf (stdZ) are also available, offering consistent calculation procedures without the need of an AIF or deconvolution. Methods: Tmax was compared to stdTTP, zf-, and stdZ to evaluate robustness of infarct volume estimation in 66 patients, using data from two different sites and MR systems (i.e., 1.5T vs. 3T; short TR (= 689 ms) vs. medium TR (= 1,390 ms); bolus dose 0.1 or 0.2 ml/kgBW, respectively). Results: Quality factors (QF) for Tmax were 0.54 ± 0.18 (sensitivity), 0.90 ± 0.06 (specificity), and 0.87 ± 0.05 (accuracy). Though not significantly different, best specificity (0.93 ± 0.05) and accuracy (0.90 ± 0.04) were found for stdTTP with a sensitivity of 0.56 ± 0.17. Other tested parameters performed not significantly worse than Tmax and stdTTP, but absolute values of QFs were slightly lower, except for zf showing the highest sensitivity (0.72 ± 0.16). Accordingly, in ROC-analysis testing the parameter performance to predict the final infarct volume, stdTTP and zf showed the best performance. The odds for stdTTP to obtain the best prediction of the final infarct size, was 6.42 times higher compared to all other parameters (odds-ratio test; p = 2.2*10-16). Conclusion: Based on our results, we suggest to reanalyze data from large cohort studies using the parameters presented here, particularly stdTTP and zf-score, to further increase consistency of perfusion assessment in acute ischemic stroke.
doi:10.3389/fphys.2018.01945 pmid:30697166 pmcid:PMC6341064 fatcat:2scsmmq5abeuveta5dhbvjtuge

Tourism potentials of the Raska region and development of rural tourism

Mila Pavlovic, Rajko Golic
2011 Glasnik Srpskog Geografskog Društva  
. & Kličković M., 2007; Grupa autora, 2007b; Stojimirović S., 2006) .  ...  Monastery, an endowment of King Stefan Uroš I, was built in the mid XII century. Marble sarcophagus in the Uroš's tomb in the southern part of the church has been preserved to this day.  ... 
doi:10.2298/gsgd1103039p fatcat:ubv3jhl2n5belfzziytcd4x4a4

Abstracts from "Imaging in Neuromuscular Disease 2019: Second International Conference on Imaging in Neuromuscular Disease, 17th – 19th November 2019 | Berlin, Germany"

2019 Journal of Neuromuscular Diseases  
A., 20 S19 Klickovic, Uros, 26, 46, 53 S23, S38, S44 Koeks, Z., 41 S35 Kopf, Stefan, 55 S45 Koumako, Cedi, 33 S29 Kurz, Felix T., 55 S45 Lawal, Tokunbor A., 59 S48 Lefebvre, Marie-Noëlle  ...  Aims: The aim of this study was to study a long cohort of patients with late onset Pompe disease [3] Uros Klickovic Skeletal muscle MRI differentiates SBMA and ALS and correlates with disease severity  ... 
doi:10.3233/jnd-199002 pmid:31744016 pmcid:PMC6918898 fatcat:c2q4eqos5racxibieebsslw2oe