Investigative radiology
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Investigative radiology · Feb 2016
Optimized Fast Dynamic Contrast-Enhanced Magnetic Resonance Imaging of the Prostate: Effect of Sampling Duration on Pharmacokinetic Parameters.
The aim of this study was to evaluate the effect of sampling duration on pharmacokinetic parameters from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and their diagnostic accuracy regarding the detection of potentially malignant prostate lesions. ⋯ Using fast optimized DCE-MRI of the prostate, a minimum sampling duration of 150 seconds is required for sufficient pharmacokinetic parameter estimates, providing a high diagnostic accuracy regarding the discrimination between benign and potentially malignant lesions.
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Investigative radiology · Feb 2016
Dual-Energy Computed Tomography Angiography of the Lower Extremity Runoff: Impact of Noise-Optimized Virtual Monochromatic Imaging on Image Quality and Diagnostic Accuracy.
The aim of this study was to evaluate the impact of a noise-optimized virtual monochromatic imaging algorithm (VMI+) on image quality and diagnostic accuracy at dual-energy computed tomography angiography (CTA) of the lower extremity runoff. ⋯ Image reconstruction using low-kiloelectron volt VMI+ improves image quality and diagnostic accuracy compared with traditional VMI technique and standard linear blending for evaluation of the lower extremity runoff using dual-energy CTA.
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Investigative radiology · Feb 2016
Signal Increase on Unenhanced T1-Weighted Images in the Rat Brain After Repeated, Extended Doses of Gadolinium-Based Contrast Agents: Comparison of Linear and Macrocyclic Agents.
In this prospective preclinical study, we evaluated T1-weighted signal intensity in the deep cerebellar nuclei (CN) and globus pallidus (GP) up to 24 days after repeated administration of linear and macrocyclic gadolinium-based contrast agents (GBCAs) using homologous imaging and evaluation methods as in the recently published retrospective clinical studies. In a second part of the study, cerebrospinal fluid (CSF) spaces were evaluated for contrast enhancement by fluid-attenuated magnetic resonance imaging (MRI). ⋯ In this animal study in rats, increased signal intensity in the CN was found up to 24 days after multiple, extended doses of linear GBCAs. However, in contrast to clinical reports, the signal enhancement in the GP was not reproduced, demonstrating the limitations of this animal experiment. The elevated signal intensities remained persistent over the entire observation period. In contrast, no changes of signal intensities in either the CN or the GP were observed for macrocyclic GBCAs. However, all GBCAs investigated were able to pass the blood-CSF barrier in rats to a certain, not yet quantified extent.
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Investigative radiology · Jan 2016
Comparative StudyComprehensive Oncologic Imaging in Infants and Preschool Children With Substantially Reduced Radiation Exposure Using Combined Simultaneous ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography/Magnetic Resonance Imaging: A Direct Comparison to ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.
The aim of this study was to evaluate the clinical applicability and technical feasibility of fluorodeoxyglucose (FDG) positron emission tomography (PET)/magnetic resonance imaging (MRI) compared with FDG PET/computed tomography (CT) in young children focusing on lesion detection, PET quantification, and potential savings in radiation exposure. ⋯ FDG PET/MRI is at least equivalent to FDG PET/CT for oncologic imaging in young children. Specifically, superior soft tissue contrast of MRI results in higher confidence in lesion interpretation. Substantial savings in radiation exposure can be achieved, and the number of necessary imaging examinations can be reduced using PET/MRI compared with PET/CT.
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Investigative radiology · Jan 2016
Comparative StudyComparison of Positron Emission Tomography Quantification Using Magnetic Resonance- and Computed Tomography-Based Attenuation Correction in Physiological Tissues and Lesions: A Whole-Body Positron Emission Tomography/Magnetic Resonance Study in 66 Patients.
Attenuation correction (AC) in fully integrated positron emission tomography (PET)/magnetic resonance (MR) systems plays a key role for the quantification of tracer uptake. The aim of this prospective study was to assess the accuracy of standardized uptake value (SUV) quantification using MR-based AC in direct comparison with computed tomography (CT)-based AC of the same PET data set on a large patient population. ⋯ Results obtained using different PET tracers show that MR-based AC is accurate in most tissue types, with SUV deviations generally of less than 10%. In bone, however, underestimations can be pronounced, potentially leading to inaccurate SUV quantifications. In addition, SUV overestimations were found for some lesions close to lung borders. This has to be taken into account when comparing PET/CT- and PET/MR-derived SUVs.