Investigative radiology
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Investigative radiology · Jan 2012
Randomized Controlled TrialOptimization of contrast material delivery for dual-energy computed tomography pulmonary angiography in patients with suspected pulmonary embolism.
To prospectively compare subjective and objective measures of image quality using 4 different contrast material injection protocols in dual-energy computed tomography pulmonary angiography (CTPA) studies of patients with suspected pulmonary embolism. ⋯ High iodine concentration and high IDR contrast material delivery protocols provide the best image quality of both CTPA and perfusion map images of the lung through high attenuation in the pulmonary arteries and minimization of beam-hardening artifacts.
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Investigative radiology · Jan 2012
Pulmonary embolism detection and characterization through quantitative iodine-based material decomposition images with spectral computed tomography imaging.
To assess the diagnostic value of pulmonary embolism (PE) detection and characterization through quantitative iodine-based material decomposition images with spectral computed tomography (CT) imaging. ⋯ Spectral CT imaging generated both monochromatic CTPA images for morphologic analysis of PE and material decomposition images for quantitative depiction of pulmonary blood flow and perfusion defects. Quantification of iodine density may be used as a predictor in distinguishing the presence or absence of PE and the severity of PE.
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Investigative radiology · Nov 2011
Cerebral perfusion in perinatal hypoxia and resuscitation assessed by transcranial contrast-enhanced ultrasound and 3 T MRI in newborn pigs.
Cerebrovascular factors are crucially involved in the early injury after perinatal asphyxia. With magnetic resonance imaging (MRI) and ultrasonography (US), this study aimed to quantify microvascular perfusion changes due to hypoxia and resuscitation, by comparing contrast-enhanced ultrasound (CEUS) to dynamic susceptibility contrast-enhanced (DSC)-MRI and diffusion-weighted MRI. ⋯ CEUS and DSC-MRI can detect an early temporal evolution of cerebral perfusion in perinatal hypoxia and resuscitation, reversible after 7 hours. Hyperoxic resuscitation caused early decreased cerebral perfusion, not present in the normoxic group. The combined use of CEUS and DSC-MRI can provide important diagnostic information and give new insights into perinatal vascular hypoxia mechanisms.
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Investigative radiology · Oct 2011
Free-breathing radial 3D fat-suppressed T1-weighted gradient echo sequence: a viable alternative for contrast-enhanced liver imaging in patients unable to suspend respiration.
: To compare free-breathing radially sampled 3D fat suppressed T1-weighted gradient-echo acquisitions (radial volumetric interpolated breath-hold examination [VIBE]) with breath-hold (BH) and free-breathing conventional (rectilinearly sampled k-space) VIBE acquisitions for postcontrast imaging of the liver. ⋯ : Radial VIBE can be performed during free breathing for contrast-enhanced imaging of the liver with comparable image quality to BH VIBE. However, further work is necessary to shorten the acquisition time to perform dynamic imaging.
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Investigative radiology · Oct 2011
Free-breathing quantitative dynamic contrast-enhanced magnetic resonance imaging in a rat liver tumor model using dynamic radial T(1) mapping.
: The high sensitivity to motion artifacts is a major limiting factor for applying the dynamic 3D T1-weighted gradient-echo (3D T1w GRE) technique for dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) experiments in small rodents. Dynamic quantification of the relaxation rate R1 (1/T1) presents an alternative approach to reduce these motion artifacts. In this work, an optimized 2D single-shot Look-Locker based T1 mapping technique, named GOLD, applying radial sampling in the golden-angle view order and contrast-enhancing k-space filter was evaluated for its use in free-breathing quantitative DCE-MRI of rat liver on a clinical 1.5 T MRI system. ⋯ : The GOLD technique allowed dynamic sampling of 2D axial T1 maps of the rat abdomen with 6-second temporal resolution enabling simultaneous and robust pharmacokinetic modeling of HCC, normal liver, and spinal muscle.