Kilian Weiss

MRI biomarkers of proximal nerve injury in CIDP

To evaluate the utility of nerve diffusion tensor imaging (DTI), nerve cross‐sectional area, and muscle magnetic resonance imaging (MRI) multiecho Dixon for assessing proximal nerve injury in chronic inflammatory demyelinating polyneuropathy (CIDP).

Effect of resistance training with vibration and compression on the formation of muscle and bone

In this study we investigated the effects of resistance training with vibration in combination with leg compression to restrict blood flow on strength, muscle oxygenation, muscle mass, and bone formation.

Clinical Evaluation of Free-Breathing Contrast-Enhanced T1w MRI of the Liver using Pseudo Golden Angle Radial k-Space Sampling

PURPOSEnContrast-enhanced T1-weighted MR imaging of the liver is typically acquired using breath-hold techniques to reduce motion artifacts and to allow for optimal diagnostic image quality. Insufficient breath-holds during MR data collection can cause severe reduction of image quality up to the point of being non-diagnostic. The aim of this study was to evaluate the subjective and objective clinical image quality of a novel free-breathing radial k-space sampling MR technique.nnnMATERIALS AND METHODSnConsent for this study was given by the local IRB committee. 86 patients who underwent both breath-hold (BH) and free-breathing (FB) late-phase contrast T1w-FS-FFE liver MRI using conventional BH Cartesian (Cartesian-eTHRIVE) and FB pseudo golden angle radial k-space sampling (Radial-eTHRIVE) were included in this retrospective analysis. Subjective analysis comprised 5-point Likert scale ratings (1u200a=u200avery good; 5u200a=u200anon-diagnostic) for artifact impact, anatomic sharpness, vessel sharpness, contrast impression, and overall diagnostic quality. Relative signal intensities in different ROIs were compared between Cartesian-eTHRIVE and Radial-eTHRIVE. For statistical differences paired Wilcoxon test and paired t-test have been performed (pu200a<u200a0.05).nnnRESULTSnThe MR scan time was significantly longer for FB Radial-eTHRIVE (2u200amin, 54u200as) compared to BH Cartesian-eTHRIVE (0u200amin 15u200as). Cartesian-eTHRIVE demonstrated a superior subjective contrast impression and objective measurements revealed an increased lesion-to-liver-contrast for hypointense liver lesions (Hypo-LTLC: 0.33u200a±u200a0.19 vs. 0.20u200a±u200a0.11; pu200a=u200a0.000), while no difference was observed for hyperintense liver lesions (Hyper-LTLC). Subjective evaluation showed superior anatomic sharpness ratings by both readers for Radial-eTHRIVE. Most importantly, in a subgroup analysis of patients who were unable to perform adequate breath-holds, free-breathing Radial-eTHRIVE still demonstrated good subjective image quality.nnnCONCLUSIONnFree-breathing, radial k-space sampling T1w MRI of the liver delivers high diagnostic image quality, especially in patients who are unable to adequately perform breath-hold maneuvers. Thus, Radial-eTHRIVE can be an important clinical alternative in patients with impaired respiration status.nnnKEY POINTSn· Delayed-phase contrast-enhanced MRI of the liver can be robustly performed using a pseudo golden angle Radial-eTHRIVE sequence.. · Free-breathing Radial-eTHRIVE yields good diagnostic image quality in case of a high artifact burden in breath-hold Cartesian-eTHRIVE and thus could be used as a back-up for patients with impaired respiratory capacity.. · A lower lesion-to-liver-contrast ratio is observed for hypointense liver lesions in free-breathing Radial-eTHRIVE sequence..nnnCITATION FORMATn· Hedderich DM, Weiss K, Spiro JE etu200aal. Clinical Evaluation of Free-Breathing Contrast-Enhanced T1w MRI of the Liver using Pseudo Golden Angle Radial k-Space Sampling. Fortschr Röntgenstr 2018; 190: 601u200a-u200a609.

Modernes MR-Protokoll für die Leberbildgebung

ZusammenfassungDie Magnetresonanztomographie (MRT) der Leber ist in der radiologischen Diagnostik fokaler und diffuser Lebererkrankungen fest etabliert und untersteht einem steten Wandel durch den fortwährenden technischen Fortschritt. Durch Neuerungen bei der Hardware, den Sequenzen und der Bildnachverarbeitung konnten in den letzten Jahren deutliche Fortschritte erzielt werden. Insbesondere auf dem Gebiet der Untersuchungssequenzen kam es zu Entwicklungen, die das diagnostische Spektrum der MRT erweiterten, zu einer Verkürzung der Scanzeit führten und zu einer Verbesserung der Bildqualität beitrugen.Gegenstand dieses Artikels ist es, den technischen Hintergrund und die klinische Anwendung neuerer Sequenztechniken zu erklären und so die Möglichkeiten und den Umfang eines modernen MRT-Untersuchungsprotokolls für die Leber darzustellen.AbstractMagnetic resonance imaging (MRI) of the liver has become an essential tool in the radiological diagnostics of both focal and diffuse diseases of the liver and is subject to constant change due to technological progress. Recently, important improvements could be achieved by innovations regarding MR hardware, sequences and postprocessing methods. The diagnostic spectrum of MRI could be broadened particularly due to new examination sequences, while at the same time scanning time could be shortened and image quality has been improved. The aim of this article is to explain both the technological background and the clinical application of recent MR sequence developments and to present the scope of a modern MRI protocol for the liver.Magnetic resonance imaging (MRI) of the liver has become an essential tool in the radiological diagnostics of both focal and diffuse diseases of the liver and is subject to constant change due to technological progress. Recently, important improvements could be achieved by innovations regarding MR hardware, sequences and postprocessing methods. The diagnostic spectrum of MRI could be broadened particularly due to new examination sequences, while at the same time scanning time could be shortened and image quality has been improved. The aim of this article is to explain both the technological background and the clinical application of recent MR sequence developments and to present the scope of a modern MRI protocol for the liver.

Modern magnetic resonance imaging of the liver

ZusammenfassungDie Magnetresonanztomographie (MRT) der Leber ist in der radiologischen Diagnostik fokaler und diffuser Lebererkrankungen fest etabliert und untersteht einem steten Wandel durch den fortwährenden technischen Fortschritt. Durch Neuerungen bei der Hardware, den Sequenzen und der Bildnachverarbeitung konnten in den letzten Jahren deutliche Fortschritte erzielt werden. Insbesondere auf dem Gebiet der Untersuchungssequenzen kam es zu Entwicklungen, die das diagnostische Spektrum der MRT erweiterten, zu einer Verkürzung der Scanzeit führten und zu einer Verbesserung der Bildqualität beitrugen.Gegenstand dieses Artikels ist es, den technischen Hintergrund und die klinische Anwendung neuerer Sequenztechniken zu erklären und so die Möglichkeiten und den Umfang eines modernen MRT-Untersuchungsprotokolls für die Leber darzustellen.AbstractMagnetic resonance imaging (MRI) of the liver has become an essential tool in the radiological diagnostics of both focal and diffuse diseases of the liver and is subject to constant change due to technological progress. Recently, important improvements could be achieved by innovations regarding MR hardware, sequences and postprocessing methods. The diagnostic spectrum of MRI could be broadened particularly due to new examination sequences, while at the same time scanning time could be shortened and image quality has been improved. The aim of this article is to explain both the technological background and the clinical application of recent MR sequence developments and to present the scope of a modern MRI protocol for the liver.Magnetic resonance imaging (MRI) of the liver has become an essential tool in the radiological diagnostics of both focal and diffuse diseases of the liver and is subject to constant change due to technological progress. Recently, important improvements could be achieved by innovations regarding MR hardware, sequences and postprocessing methods. The diagnostic spectrum of MRI could be broadened particularly due to new examination sequences, while at the same time scanning time could be shortened and image quality has been improved. The aim of this article is to explain both the technological background and the clinical application of recent MR sequence developments and to present the scope of a modern MRI protocol for the liver.

Self-gated golden-angle spiral 4D flow MRI: Self-Gated Golden-Angle Spiral 4D Flow

The acquisition of 4D flow magnetic resonance imaging (MRI) in cardiovascular applications has recently made large progress toward clinical feasibility. The need for simultaneous compensation of cardiac and breathing motion still poses a challenge for widespread clinical use. Especially, breathing motion, addressed by gating approaches, can lead to unpredictable and long scan times. The current work proposes a time‐efficient self‐gated 4D flow sequence that exploits up to 100% of the acquired data and operates at a predictable scan time.

4D flow MRI for the analysis of celiac trunk and mesenteric artery stenoses

PURPOSEnThis study aims to assess the feasibility of 4D flow MRI measurements in complex vascular territories; namely, the celiac artery (CA) and superior mesenteric artery (SMA).nnnMATERIALS AND METHODSnIn this prospective study, 22 healthy volunteers and 10 patients were scanned at 3u202fT. Blood flow parameters were compared between healthy volunteers and patients with stenosis of the CA and/or SMA as a function of stenosis grade characterized by prior contrast-enhanced computed tomography (CE-CT). The 4D flow MRI acquisition covered the CA, SMA and adjusting parts of the abdominal aorta (AO). Measurements of velocity- (peak velocity [PV], average velocity [AV]) and volume-related parameters (peak flow [PF], stroke volume [SV]) were conducted. Further, stenosis grade and wall shear stress in the CA, SMA and AO were evaluated.nnnRESULTSnIn patients, prior evaluation by CE-CT revealed 11 low- and 5 mid-grade stenoses of the CA and/or SMA. PV and AV were significantly higher in patients than in healthy volunteers [PV: pu202f<u202f0.0001; AV: pu202f=u202f0.03, pu202f<u202f0.001]. PF and SV did not differ significantly between healthy volunteers and patients; however, a trend towards lower PF and SV could be detected in patients with mid-grade stenoses. Comparison of 4D flow MRI with CE-CT revealed a strong positive correlation in estimated degree of stenosis (CA: ru202f=u202f0.86, SMA: ru202f=u202f0.98). Patients with mid-grade stenoses had a significantly higher average WSS magnitude (AWM) than healthy volunteers (pu202f=u202f0.02).nnnCONCLUSIONnThis feasibility study suggests that 4D flow MRI is a viable technique for the evaluation of complex flow characteristics in small vessels such as the CA and SMA. 4D flow MRI approves comparable to the morphologic assessment of complex vascular territories using CE-CT but, in addition, offers the functional evaluation of flow parameters that goes beyond the morphology.

Accelerated MRI of the Lumbar Spine Using Compressed Sensing: Quality and Efficiency: Accelerated MRI of the Lumbar Spine

Decreasing MRI scan time is a key factor to increase patient comfort and compliance as well as the productivity of MRI scanners.

Myocardial T1 and T2 mapping in severe aortic stenosis: Potential novel insights into the pathophysiology of myocardial remodelling

PURPOSEnSevere aortic stenosis (AS) is known to be associated with substantial myocardial remodelling, leading to diffuse myocardial fibrosis (DMF). Native myocardial T1 is emerging as a novel imaging biomarker for the non-invasive assessment of DMF. In contrast, no studies exist elucidating changes of myocardial T2 reflecting myocardial oedema in the presence of AS. The purpose of the present study was to combine native T1 and T2 mapping in order to characterize myocardial tissue changes in the setting of severe AS.nnnMETHODSnAfter obtaining ethical approval and informed consent, a total of 26 prospectively selected patients with severe AS (13 women, mean age 81u2009±u20097 years) and 17 healthy controls (12 women, mean age 63u2009±u20096 years) underwent cardiac magnetic resonance (CMR) imaging on a clinical 3u2009T scanner. The CMR protocol included a native Modified Look-Locker (MOLLI) T1 mapping and a Gradient Spin Echo (GraSE) T2-mapping sequence in three short-axis slices and one long-axis view. After segmentation, myocardial T1 and T2 values were averaged over the entire myocardium. Statistical analysis was performed using Wilcoxon sum-rank test, Welchs independent t-test and Pearsons correlation coefficient.nnnRESULTSnGlobal native myocardial T1 was significantly increased in AS patients when compared to controls (1305u2009±u200939 vs. 1272u2009±u200921u2009ms, pu2009=u2009.005). Similarly, mean myocardial T2 was significantly elevated in AS patients (51u2009±u20094 vs. 46u2009±u20092u2009ms, pu2009<u2009.001) and showed a strong correlation with native T1 (ru2009=u2009.60, pu2009<u2009.001). An overlap was observed between T1 of both groups, whereas T2 discriminated nearly perfectly between the two groups (area under the curve in ROC analyses: 0.76 for T1, 0.87 for T2).nnnCONCLUSIONSnPatients with severe AS exhibit significantly elevated native myocardial T1, which has previously been shown to correlate with the amount of myocardial collagen. Adding to this evidence, the present study is the first to show that native T1 and T2 are both significantly elevated and correlated in AS patients, pointing towards a potential role of oedematous/inflammatory processes in the pathophysiology of myocardial remodelling associated with AS.

Modernes MR-Protokoll für die Leberbildgebung@@@Modern magnetic resonance imaging of the liver

ZusammenfassungDie Magnetresonanztomographie (MRT) der Leber ist in der radiologischen Diagnostik fokaler und diffuser Lebererkrankungen fest etabliert und untersteht einem steten Wandel durch den fortwährenden technischen Fortschritt. Durch Neuerungen bei der Hardware, den Sequenzen und der Bildnachverarbeitung konnten in den letzten Jahren deutliche Fortschritte erzielt werden. Insbesondere auf dem Gebiet der Untersuchungssequenzen kam es zu Entwicklungen, die das diagnostische Spektrum der MRT erweiterten, zu einer Verkürzung der Scanzeit führten und zu einer Verbesserung der Bildqualität beitrugen.Gegenstand dieses Artikels ist es, den technischen Hintergrund und die klinische Anwendung neuerer Sequenztechniken zu erklären und so die Möglichkeiten und den Umfang eines modernen MRT-Untersuchungsprotokolls für die Leber darzustellen.AbstractMagnetic resonance imaging (MRI) of the liver has become an essential tool in the radiological diagnostics of both focal and diffuse diseases of the liver and is subject to constant change due to technological progress. Recently, important improvements could be achieved by innovations regarding MR hardware, sequences and postprocessing methods. The diagnostic spectrum of MRI could be broadened particularly due to new examination sequences, while at the same time scanning time could be shortened and image quality has been improved. The aim of this article is to explain both the technological background and the clinical application of recent MR sequence developments and to present the scope of a modern MRI protocol for the liver.Magnetic resonance imaging (MRI) of the liver has become an essential tool in the radiological diagnostics of both focal and diffuse diseases of the liver and is subject to constant change due to technological progress. Recently, important improvements could be achieved by innovations regarding MR hardware, sequences and postprocessing methods. The diagnostic spectrum of MRI could be broadened particularly due to new examination sequences, while at the same time scanning time could be shortened and image quality has been improved. The aim of this article is to explain both the technological background and the clinical application of recent MR sequence developments and to present the scope of a modern MRI protocol for the liver.