Frahm, Jens

[["dc.bibliographiccitation.artnumber","3527269"],["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.journal","Computational and Mathematical Methods in Medicine"],["dc.bibliographiccitation.lastpage","11"],["dc.bibliographiccitation.volume","2017"],["dc.contributor.author","Schaetz, Sebastian"],["dc.contributor.author","Voit, Dirk"],["dc.contributor.author","Frahm, Jens"],["dc.contributor.author","Uecker, Martin"],["dc.date.accessioned","2019-07-09T11:45:03Z"],["dc.date.accessioned","2020-05-13T11:05:04Z"],["dc.date.available","2019-07-09T11:45:03Z"],["dc.date.available","2020-05-13T11:05:04Z"],["dc.date.issued","2017"],["dc.description.abstract","To develop generic optimization strategies for image reconstruction using graphical processing units (GPUs) in magnetic resonance imaging (MRI) and to exemplarily report on our experience with a highly accelerated implementation of the nonlinear inversion (NLINV) algorithm for dynamic MRI with high frame rates."],["dc.identifier.doi","10.1155/2017/3527269"],["dc.identifier.pmid","29463984"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/15017"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59150"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/65303"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.eissn","1748-6718"],["dc.relation.issn","1748-670X"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.subject.ddc","610"],["dc.title","Accelerated Computing in Magnetic Resonance Imaging: Real-Time Imaging Using Nonlinear Inverse Reconstruction"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber",";e4184"],["dc.bibliographiccitation.journal","NMR in Biomedicine"],["dc.contributor.author","Kollmeier, Jost M."],["dc.contributor.author","Tan, Zhengguo"],["dc.contributor.author","Joseph, Arun A."],["dc.contributor.author","Kalentev, Oleksandr"],["dc.contributor.author","Voit, Dirk"],["dc.contributor.author","Merboldt, K. Dietmar"],["dc.contributor.author","Frahm, Jens"],["dc.date.accessioned","2019-11-14T10:39:33Z"],["dc.date.accessioned","2021-10-27T13:21:27Z"],["dc.date.available","2019-11-14T10:39:33Z"],["dc.date.available","2021-10-27T13:21:27Z"],["dc.date.issued","2019"],["dc.description.abstract","The purpose of this work was to develop an acquisition and reconstruction technique for two- and three-directional (2d and 3d) phase-contrast flow MRI in real time. A previous real-time MRI technique for one-directional (1d) through-plane flow was extended to 2d and 3d flow MRI by introducing in-plane flow sensitivity. The method employs highly undersampled radial FLASH sequences with sequential acquisitions of two or three flow-encoding datasets and one flow-compensated dataset. Echo times are minimized by merging the waveforms of flow-encoding and radial imaging gradients. For each velocity direction individually, model-based reconstructions by regularized nonlinear inversion jointly estimate an anatomical image, a set of coil sensitivities and a phase-contrast velocity map directly. The reconstructions take advantage of a dynamic phase reference obtained by interpolating consecutive flow-compensated acquisitions. Validations include pulsatile flow phantoms as well as in vivo studies of the human aorta at 3 T. The proposed method offers cross-sectional 2d and 3d flow MRI of the human aortic arch at 53 and 67 ms resolution, respectively, without ECG synchronization and during free breathing. The in-plane resolution was 1.5 × 1.5 mm2 and the slice thickness 6 mm. In conclusion, real-time multi-directional flow MRI offers new opportunities to study complex human blood flow without the risk of combining differential phase (i.e., velocity) information from multiple heartbeats as for ECG-gated data. The method would benefit from a further reduction of acquisition time and accelerated computing to allow for extended clinical trials."],["dc.identifier.doi","10.1002/nbm.4184"],["dc.identifier.pmid","31580524"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/16662"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/92022"],["dc.language.iso","en"],["dc.notes.intern","Migrated from goescholar"],["dc.relation.eissn","1099-1492"],["dc.relation.issn","1099-1492"],["dc.relation.issn","0952-3480"],["dc.relation.orgunit","Universitätsmedizin Göttingen"],["dc.rights","CC BY-NC-ND 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by-nc-nd/4.0"],["dc.subject.ddc","610"],["dc.title","Real‐time multi‐directional flow MRI using model‐based reconstructions of undersampled radial FLASH – A feasibility study"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","81"],["dc.bibliographiccitation.journal","Annals of Neurology"],["dc.bibliographiccitation.lastpage","93"],["dc.bibliographiccitation.volume","66"],["dc.contributor.author","Gadjanski, Ivana"],["dc.contributor.author","Boretius, Susann"],["dc.contributor.author","Williams, Sarah K."],["dc.contributor.author","Lingor, Paul"],["dc.contributor.author","Knöferle, Johanna"],["dc.contributor.author","Sättler, Muriel B."],["dc.contributor.author","Fairless, Richard"],["dc.contributor.author","Hochmeister, Sonja"],["dc.contributor.author","Sühs, Kurt-Wolfram"],["dc.contributor.author","Michaelis, Thomas"],["dc.contributor.author","Frahm, Jens"],["dc.contributor.author","Storch, Maria K."],["dc.contributor.author","Bähr, Mathias"],["dc.contributor.author","Diem, Ricarda"],["dc.date.accessioned","2019-07-09T11:52:52Z"],["dc.date.available","2019-07-09T11:52:52Z"],["dc.date.issued","2009"],["dc.description.abstract","Objective: The aim of this study was to investigate the role of voltage-dependent calcium channels (VDCCs) in axon degeneration during autoimmune optic neuritis. Methods: Calcium ion (Ca2 ) influx into the optic nerve (ON) through VDCCs was investigated in a rat model of optic neuritis using manganese-enhanced magnetic resonance imaging and in vivo calcium imaging. After having identified the most relevant channel subtype (N-type VDCCs), we correlated immunohistochemistry of channel expression with ON histopathology. In the confirmatory part of this work, we performed a treatment study using -conotoxin GVIA, an N-type specific blocker. Results: We observed that pathological Ca2 influx into ONs during optic neuritis is mediated via N-type VDCCs. By analyzing the expression of VDCCs in the inflamed ONs, we detected an upregulation of 1B, the pore-forming subunit of N-type VDCCs, in demyelinated axons. However, high expression levels were also found on macrophages/activated microglia, and lower levels were detected on astrocytes. The relevance of N-type VDCCs for inflammation-induced axonal degeneration and the severity of optic neuritis was corroborated by treatment with -conotoxin GVIA. This blocker led to decreased axon and myelin degeneration in the ONs together with a reduced number of macrophages/activated microglia. These protective effects were confirmed by analyzing the spinal cords of the same animals. Interpretation: We conclude that N-type VDCCs play an important role in inflammation-induced axon degeneration via two mechanisms: First, they directly mediate toxic Ca2 influx into the axons; and second, they contribute to macrophage/microglia function, thereby promoting secondary axonal damage."],["dc.identifier.doi","10.1002/ ana.21668"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/6088"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/60296"],["dc.language.iso","en"],["dc.subject.ddc","610"],["dc.title","Role of N-Type Voltage-Dependent Calcium Channels in Autoimmune Optic Neuritis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.journal","The Open Medical Imaging Journal"],["dc.bibliographiccitation.lastpage","9"],["dc.bibliographiccitation.volume","5"],["dc.contributor.author","Zhang, Shuo"],["dc.contributor.author","Gersdorff, Nikolaus"],["dc.contributor.author","Frahm, Jens"],["dc.date.accessioned","2019-07-10T08:13:54Z"],["dc.date.available","2019-07-10T08:13:54Z"],["dc.date.issued","2011"],["dc.description.abstract","This study evaluated the use of a novel real-time MRI technique based on fast low angle shot (FLASH) MRI with radial encoding, gridding reconstruction, and sliding window for the assessment of temporomandibular joint (TMJ) dynamics in a cohort of 30 young volunteers without prior diagnosis of TMJ pathology. High-resolution images (0.75 􀀁 0.75 mm2, 5 mm section thickness) were obtained at 3 frames per second for active jaw movements without adjunctive devices. Real-time movies were evaluated with respect to image artefacts, anatomical visibility, diagnostic confidence, and TMJ function. During the entire opening and closing of the mouth, the relative positions of the mandibular condyle and articular disc were well depicted. Mean scores were 1.01 ± 0.65 for motion artefacts (scale: 0 = no to 3 = severe artefacts) and 2.03 ± 0.71 for anatomical detectability (scale: 1 = excellent to 5 = not visible). High inter-observer agreements were found for assessments of mandibular condyle movements (􀀁 = 0.83) and articular disc displacements (􀀁 = 0.91). In latter cases, the point of disc reduction could precisely be identified. In conclusion, the proposed real-time MRI method offers robust access to TMJ dynamics with good image quality."],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/7837"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/61375"],["dc.language.iso","en"],["dc.notes.intern","Migrated from goescholar"],["dc.rights.access","openAccess"],["dc.subject","Temporomandibular joint; magnetic resonance; MRI; dynamic MRI; joint"],["dc.subject.ddc","610"],["dc.title","Real-Time Magnetic Resonance Imaging of Temporomandibular Joint Dynamics"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","101639"],["dc.bibliographiccitation.journal","NeuroImage Clinical"],["dc.bibliographiccitation.volume","21"],["dc.contributor.author","Maier, Ilko L."],["dc.contributor.author","Hofer, Sabine"],["dc.contributor.author","Joseph, Arun A."],["dc.contributor.author","Merboldt, K.-Dietmar"],["dc.contributor.author","Eggert, Eva"],["dc.contributor.author","Behme, Daniel"],["dc.contributor.author","Schregel, Katharina"],["dc.contributor.author","Brelie, Christian von der"],["dc.contributor.author","Rohde, Veit"],["dc.contributor.author","Koch, Jan-Christoph"],["dc.contributor.author","Psychogios, Marios-Nikos"],["dc.contributor.author","Frahm, Jens"],["dc.contributor.author","Liman, Jan"],["dc.contributor.author","Bähr, Mathias"],["dc.date.accessioned","2019-07-09T11:50:09Z"],["dc.date.available","2019-07-09T11:50:09Z"],["dc.date.issued","2019"],["dc.description.abstract","BACKGROUND: Degenerative changes of the cervical spinal column are the most common cause of spinal cord lesions in the elderly. Conventional clinical, electrophysiological and radiological diagnostics of spinal cord compression are often inconsistent. MATERIALS AND METHODS: The feasibility and diagnostic potential of a novel T1 mapping method at 0.5 mm resolution and 4 s acquisition time was evaluated in 14 patients with degenerative cervical spinal canal stenosis (SCS) and 6 healthy controls. T1 mapping was performed in axial sections of the stenosis as well as above and below. All subjects received standard T2-weighted MRI of the cervical spine (including SCS-grading 0-III), electrophysiological and clinical examinations. RESULTS: Patients revealed significantly decreased T1 relaxation times of the compressed spinal cord within the SCS (912 ± 53 ms, mean ± standard deviation) in comparison to unaffected segments above (1027 ± 39 ms, p < .001) and below (1056 ± 93 ms, p < .001). There was no difference in mean T1 in unaffected segments in patients (p = .712) or between segments in controls (p = .443). Moreover, T1 values were significantly lower in grade II (881 ± 46 ms, p = .005) than in grade I SCS (954 ± 29 ms). Patients with central conduction deficit tended to have lower T1 values within the SCS than patients without (909 ± 50 ms vs 968 ± 7 ms, p = .069). CONCLUSION: Rapid high-resolution T1 mapping is a robust MRI method for quantifying spinal cord compression in patients with cervical SCS. It promises additional diagnostic insights and warrants more extended patient studies."],["dc.identifier.doi","10.1016/j.nicl.2018.101639"],["dc.identifier.pmid","30553763"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/15872"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/59713"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","2213-1582"],["dc.rights","CC BY-ND 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by-nd/4.0"],["dc.subject.ddc","610"],["dc.title","Quantification of spinal cord compression using T1 mapping in patients with cervical spinal canal stenosis - Preliminary experience"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]