Search results for "MRI"
showing 10 items of 733 documents
Resectable and borderline resectable pancreatic ductal adenocarcinoma: Role of the radiologist and oncologist in the era of precision medicine
2021
The incidence and mortality of pancreatic ductal adenocarcinoma are growing over time. The management of patients with pancreatic ductal adenocarcinoma involves a multidisciplinary team, ideally involving experts from surgery, diagnostic imaging, interventional endoscopy, medical oncology, radiation oncology, pathology, geriatric medicine, and palliative care. An adequate staging of pancreatic ductal adenocarcinoma and re-assessment of the tumor after neoadjuvant therapy allows the multidisciplinary team to choose the most appropriate treatment for the patient. This review article discusses advancement in the molecular basis of pancreatic ductal adenocarcinoma, diagnostic tools available fo…
Rectal cancer: Assessment of response to neoadjuvant chemoradiation by dynamic contrast-enhanced MRI
2012
Purpose To assess pretreatment functional and morphological tumor characteristics with magnetic resonance imaging (MRI) in advanced rectal carcinoma and to identify factors predicting response to neoadjuvant chemoradiation. Materials and Methods In a prospective study, 95 patients with rectal carcinoma underwent dynamic contrast-enhanced MRI before and after chemoradiation. Quantitative parameters were derived from a pharmacokinetic two-compartment model. Tumors were also characterized with regard to mucinous status at pretreatment high-resolution MRI as nonmucinous or mucinous. Response to treatment was defined as a downshift in the local tumor stage. Results The parameter k21 (contrast me…
Data-driven analysis for fMRI during naturalistic music listening
2017
Interest towards higher ecological validity in functional magnetic resonance imaging (fMRI) experiments has been steadily growing since the turn of millennium. The trend is reflected in increasing amount of naturalistic experiments, where participants are exposed to the real-world complex stimulus and/or cognitive tasks such as watching movie, playing video games, or listening to music. Multifaceted stimuli forming parallel streams of input information, combined with reduced control over experimental variables introduces number of methodological challenges associated with isolating brain responses to individual events. This exploratory work demonstrated some of those methodological challeng…
Frequency-specific network activity predicts bradykinesia severity in Parkinson’s disease
2021
Highlights • Parallel subnetworks are affected in bradykinesia. • The primary motor and the premotor cortex are common nodes with task-specificity. • Beta activity decreases, gamma activity increases with improvement of bradykinesia. • Subthalamic stimulation reduces beta, increases gamma power in ipsilateral cortex. • Subnetworks act with frequency-specific oscillations.
Peritumoral perfusion and proton spectroscopic MR imaging in the differentiation of gliomas and solitary metastases
2015
Purpose: To asses the value of peritumoural perfusion-weighted and proton spectroscopic MR imaging in preoperative grading of gliomas and in differentiating between primary gliomas and solitary metastases. Methods and Materials: Ten low-grade gliomas, eight high-grade gliomas, and ten metastases were prospectively evaluated with MR imaging, dynamic susceptibility contrast-enhanced perfusion imaging, and single-voxel proton MR spectroscopy before surgical resection or stereotactic biopsy. Maximal rCBV values and maximal Cho/Cr ratios were calculated from peritumoural region surrounding the tumour. Tumour grade presumed with these values was compared to histopathologic grading. Differences in…
Imaging of Substantia Nigra in Parkinson's Disease: A Narrative Review.
2021
Parkinson’s disease (PD) is a progressive neurodegenerative disorder, characterized by motor and non-motor symptoms due to the degeneration of the pars compacta of the substantia nigra (SNc) with dopaminergic denervation of the striatum. Although the diagnosis of PD is principally based on a clinical assessment, great efforts have been expended over the past two decades to evaluate reliable biomarkers for PD. Among these biomarkers, magnetic resonance imaging (MRI)-based biomarkers may play a key role. Conventional MRI sequences are considered by many in the field to have low sensitivity, while advanced pulse sequences and ultra-high-field MRI techniques have brought many advantages, partic…
Longitudinal 18F-FDG PET and MRI Reveal Evolving Imaging Pathology That Corresponds to Disease Progression in a Patient With ALS-FTD
2019
Single time point positron emission tomography (PET) studies of patients with amyotrophic lateral sclerosis and frontotemporal dementia (ALS-FTD), have demonstrated hypometabolism or hypermetabolism in certain brain regions. To determine whether longitudinal (at baseline and 20.4 months later) PET and magnetic resonance imaging (MRI) reveal evolving brain imaging pathology corresponding to clinical progression in a patient with ALS-FTD, cerebral glucose metabolic rate, cortical thickness (CT) and cortical area (CA) were obtained and symmetric percent change (SPC) for each calculated. The patient had worsening symptoms and signs of bulbar-onset upper motor neuron-predominant ALS as well as l…
Widespread white matter microstructural abnormalities in bipolar disorder: evidence from mega- and meta-analyses across 3033 individuals
2019
Fronto-limbic white matter (WM) abnormalities are assumed to lie at the heart of the pathophysiology of bipolar disorder (BD);\ud however, diffusion tensor imaging (DTI) studies have reported heterogeneous results and it is not clear how the clinical\ud heterogeneity is related to the observed differences. This study aimed to identify WM abnormalities that differentiate patients with\ud BD from healthy controls (HC) in the largest DTI dataset of patients with BD to date, collected via the ENIGMA network. We gathered\ud individual tensor-derived regional metrics from 26 cohorts leading to a sample size of N = 3033 (1482 BD and 1551 HC). Mean\ud fractional anisotropy (FA) from 43 regions of i…
Radiolabeled DNase, a potential indicator for noninvasive detection of tissue damage
1983
Pancreatic DNase I was labeled with 131I or fluorescamine and injected IV into NMRI mice bearing a sarcoma 180. Of the injected tracer, 1.5%-2% was found to accumulate per g tumor. In sections of tumor tissue DNase was localized in damaged cells in solid and necrotic tumor regions. This binding is most probably due to specific interaction of DNase with actin, an ubiquitous cytoskeletal protein. Two-component blood clearance with a rapid first component (two-thirds of applied radioactivity) was observed. The labeled tumor could easily be visualized by gamma camera imaging. The findings suggest DNase to be a potent radiopharmaceutical for imaging damaged tissue, occurring in malignant tumors …
Brain iron deposition after Ferumoxytol-enhanced MRI: A study of Porcine Brains
2020
Recent evidence of gadolinium deposition in the brain has raised safety concerns. Iron oxide nanoparticles are re-emerging as promising alternative MR contrast agents, because the iron core can be metabolized. However, long-term follow up studies of the brain after intravenous iron oxide administration have not been reported thus far. In this study, we investigated, if intravenously administered ferumoxytol nanoparticles are deposited in porcine brains. Methods: In an animal care and use committee-approved prospective case-control study, ten Gottingen minipigs received either intravenous ferumoxytol injections at a dose of 5 mg Fe/kg (n=4) or remained untreated (n=6). Nine to twelve months …