Publications by authors named "Georg Bier"
Background And Purpose: To compare the accuracy of subjective Alberta Stroke Program Early CT Score (sASPECTS) evaluation and that of an automated prototype software (aASPECTS) on nonenhanced CT (NECT) in patients with early anterior territory stroke and controls using side-to-side quantification of hypoattenuated brain areas.
Methods: We retrospectively analyzed the NECT scans of 42 consecutive patients with ischemic stroke before reperfusion and 42 controls using first sASPECTS and subsequently aASPECTS. We assessed the differences in Alberta Stroke Program Early CT Score (ASPECTS) and calculated the sensitivity and specificity of NECT with CT perfusion, whereas cerebral blood volume (CBV) served as the reference standard for brain infarction.
(1) Background: to test the diagnostic performance of a fully convolutional neural network-based software prototype for clot detection in intracranial arteries using non-enhanced computed tomography (NECT) imaging data. (2) Methods: we retrospectively identified 85 patients with stroke imaging and one intracranial vessel occlusion. An automated clot detection prototype computed clot location, clot length, and clot volume in NECT scans.
View Article and Find Full Text PDFDiagnosing liver lesions is challenging. CT is used for primary diagnosis, but its contrast resolution is limited. Investigating methods to improve detection of liver lesions is important.
View Article and Find Full Text PDFPurpose: To investigate the diagnostic value of three-dimensional morphologic measurements of the Eustachian tube on computed tomography in Eustachian tube dysfunction.
Method: This prospective cross-sectional observational study includes forty patients with unilateral Eustachian tube dysfunction. The clinical diagnosis is verified using the Eustachian tube score - 7 and the Eustachian tube dysfunction questionnaire - 7.
Objective: To determine whether thrombectomy is safe in children up to 24 hours after onset of symptoms when selected by mismatch between clinical deficit and infarct.
Methods: A secondary analysis of the Save ChildS Study (January 2000-December 2018) was performed, including all pediatric patients (<18 years) diagnosed with arterial ischemic stroke who underwent endovascular recanalization at 27 European and United States stroke centers. Patients were included if they had a relevant mismatch between clinical deficit and infarct.
Background and Purpose- The recent Save ChildS study provides multicenter evidence for the use of mechanical thrombectomy in children with large vessel occlusion arterial ischemic stroke. However, device selection for thrombectomy may influence rates of recanalization, complications, and neurological outcomes, especially in pediatric patients of different ages. We, therefore, performed additional analyses of the Save ChildS data to investigate a possible association of different thrombectomy techniques and devices with angiographic and clinical outcome parameters.
View Article and Find Full Text PDFImportance: Randomized clinical trials have shown the efficacy of thrombectomy of large intracranial vessel occlusions in adults; however, any association of therapy with clinical outcomes in children is unknown.
Objective: To evaluate the use of endovascular recanalization in pediatric patients with arterial ischemic stroke.
Design, Setting, And Participants: This retrospective, multicenter cohort study, conducted from January 1, 2000, to December 31, 2018, analyzed the databases from 27 stroke centers in Europe and the United States.
Introduction: Practice guidelines for adult BCVI patients have been implemented recently, but data for this devastating injury pattern in children are still limited. An international multicenter analysis was performed to characterize BCVI in the pediatric population.
Methods: The TraumaRegister DGU, a prospectively maintained database, was analyzed (01/2002-12/2015).
Background: It is still controversial whether an increased proliferation index is correlated with the tumor invasiveness of pituitary adenomas. A homogeneous large monocentric series of pituitary adenomas was retrospectively analyzed. The correlation between the proliferation indices (Ki-67 and p53 expression levels) and invasiveness and size of pituitary adenomas was investigated in primary operated and recurrent adenomas.
View Article and Find Full Text PDFPurpose: To assess the prevalence of false-positive meningeal contrast enhancement in patients with solid tumors who were undergoing chemotherapy.
Methods: A total of 2572 magnetic resonance imaging (MRI) examinations of the brain were retrospectively evaluated by two readers for the presence of pathological meningeal contrast enhancement conspicuous for neoplastic meningitis. These patients either had malignant melanoma, breast or lung cancer, or lymphoma.
Purpose: The aim of the study was to assess the predictive value of preoperatively assessed diffusion kurtosis imaging (DKI) metrics as prognostic factors in the 2016 World Health Organization Classification of Tumors of the Central Nervous System integrated glioma groups.
Material And Methods: Seventy-seven patients with histopathologically confirmed treatment-naïve glioma were retrospectively assessed between 08/2013 and 10/2017 using mean kurtosis (MK) and mean diffusivity (MD) histogram parameters from DKI, overall and progression-free survival, and relevant prognostic molecular data (isocitrate dehydrogenase, [IDH]; alpha-thalassemia/mental retardation syndrome X-linked, [ATRX]; chromosome 1p/19q loss of heterozygosity). Receiver operating characteristic (ROC) analysis was performed on metric variables to determine the optimal cutoff-values.
Purpose: To evaluate the potential benefit in image quality of the iterative reconstruction (IR) technique advanced modelled iterative reconstruction (ADMIRE) in CT angiography (CTA) of supra-aortic arteries compared to sinogram affirmed iterative reconstruction (SAFIRE) and standard filtered back projection (FBP) in one patients' group.
Methods: In this study 29 patients underwent standard CTA of supra-aortic arteries. Images were reconstructed using three different reconstruction algorithms, FBP, and IR techniques ADMIRE and SAFIRE.
Objective: To assess three strategies for evaluation and description of potential endolymphatic hydrops (EH) gradients along the cochlea in patients with Menière's disease.
Study Design: Prospective observational study.
Methods: Ten patients with definite Menière's disease revealed by magnetic resonance imaging were included in this prospectively conducted pilot study.
Purpose: The aim of this study to evaluate the role of frequency-selective nonlinear blending (FS-NLB) for the detectability of brain metastases with contrast-enhanced computed tomography (CECT) using magnetic resonance imaging (MRI) as standard of reference.
Materials And Methods: A retrospective patient data search at our institution yielded 91 patients who underwent both brain CECT and MRI for screening of brain metastases (n = 173) between 2014 and 2016 (mean time interval, 29 ± 37 [malignant: 15 ± 16/benign: 42 ± 47] days). A recently introduced FS-NLB postprocessing technique was applied to CECT images.
Aim To evaluate voxelwise computed diffusion-weighted imaging (vcDWI) for the detection of cytotoxic oedema in brain imaging and to quantify the benefit of lesion contrast in comparison to standard b = 1000 s/mm by the example of acute ischaemic stroke. Materials and methods A retrospective evaluation of 66 patients (63 ± 15.9 years) suspected for acute ischaemic stroke who received diffusion-weighted magnetic resonance imaging and fluid-attenuated inversion recovery sequence.
View Article and Find Full Text PDFObjectives: To investigate the accuracy of dual-energy (DE) CT-based iodine maps (IM) and noise-optimised monoenergetic extrapolations (MEI+) at 40 keV for the detection and differentiation of venous thrombosis (VT) from iodine flux artefacts (IFA) in comparison to portal-venous phase CT (CT).
Methods: Ninety-nine patients were enrolled in this study. In all patients, VT or IFA was suspected on contrast-enhanced CT and confirmed by follow-up CT or colour-coded ultrasound.
Purpose: To assess and quantify the prevalence and co-occurence of a sellar floor lowering and empty sella phenomenon in patients with GH (growth hormone)-secreting pituitary adenoma.
Methods: A total number of 159 acromegalic patients were included in this study, as well as two control groups (150 patients with non-GH-secreting adenomas and 50 patients without pituitary adenomas). Magnetic resonance images of all patients were evaluated for presence of an empty sella, downward and lateral tumor extension, and maximum superoinferior diameter of the mass.
Purpose: Tumorous texture is a marker for tumor tissue inhomogeneity. Based on this assumption, this study aims to evaluate the value of computed tomography texture analysis for imaging-based prediction of perioperative complications during laparoscopic partial tumor nephrectomy.
Methods: A total of 106 patients with histologically confirmed renal cell carcinoma and pre-operative CT were included and volumetric texture analysis of the tumors was performed by two readers.
Introduction: To assess the predictive value of magnetic resonance imaging (MRI) gadolinium enhancement as a prognostic factor in the 2016 World Health Organization Classification of Tumors of the Central Nervous System integrated glioma groups.
Methods: Four-hundred fifty patients with histopathologically confirmed glioma were retrospectively assessed between 07/1997 and 06/2014 using gadolinium enhancement, survival, and relevant prognostic molecular data [isocitrate dehydrogenase (IDH); alpha-thalassemia/mental retardation syndrome X-linked (ATRX); chromosome 1p/19q loss of heterozygosity; and O6-methylguanine DNA methyltransferase (MGMT)]. The Kaplan-Meier method was used to assess univariate survival data.
Purpose: To assess the diagnostic performance of dynamic susceptibility contrast perfusion magnetic resonance perfusion imaging (DSC-MRI) for in vivo human glioma molecular profiling.
Methods: In this study 100 patients with histopathologically confirmed glioma who provided written informed consent were retrospectively assessed between January 2016 and February 2017 in two prospective trials that were approved by the local institutional review board. Cerebral blood volume (CBV) measurements from DSC-MRI were assessed, and histogram parameters of relative CBV (rCBV) results were compared among World Health Organization (WHO) 2016 based histological findings and molecular characteristics.
Purpose: Traumatic brain injury is an important health concern in equestrian sports. Nevertheless, the use of safety helmets, especially in recreational riding, is reported to be rare. The purpose of this study was to perform the first matched-pairs analysis of traumatic brain injury with regard to the use of helmets.
View Article and Find Full Text PDFObjectives: To compare a low-dose, tin-filtered, nonenhanced, high-pitch Sn100 kVp CT protocol (Sn100) with a standard protocol (STP) for the detection of calcifications in the ascending aorta in patients scheduled for cardiac surgery.
Methods: Institutional Review Board approval for this retrospective study was waived and the study was HIPAA-compliant. The study included 192 patients (128 men; age 68.