Investigative radiology
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Investigative radiology · Jul 2009
Preclinical evaluation of a novel fiber compound MR guidewire in vivo.
Interventional magnetic resonance imaging requires dedicated and MR-compatible devices. The guidewire is a key item for intravascular interventions. Mechanical stability, good visibility during real-time imaging, and RF safety are essential. A novel fiber-compound MR guidewire (GW) was evaluated in different MR-guided interventional scenarios. ⋯ With the aid of the GW, different fully real-time MR-guided endovascular interventions become feasible.
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Investigative radiology · Jun 2009
Comparative StudyDiffusion-weighted imaging in patients with acute brain ischemia at 3 T: current possibilities and future perspectives comparing conventional echoplanar diffusion-weighted imaging and fast spin echo diffusion-weighted imaging sequences using BLADE (PROPELLER).
To compare diffusion-weighted imaging (DWI) based on a fast spin echo (FSE) sequence using BLADE (PROPELLER) with conventional DWI-echoplanar imaging (EPI) techniques at 3 T and to demonstrate the influence of hardware developments on signal-to-noise ratio (SNR) with these techniques using 12- and 32-channel head coils. ⋯ Despite lower SNR at comparable PI factors, DWI-BLADE sequences acquired using the 12-channel coil are preferable in most instances, as compared with DWI-EPI sequences, because of the absence of susceptibility artifacts and subsequently improved depiction of ischemic lesions in the brainstem and cerebellum. With the 32-channel coil, recently FDA approved, DWI-BLADE acquired with an iPAT = 2 provides comparable SNR without bulk susceptibility artifacts as compared with the DWI-EPI sequences acquired for clinical routine to date and has the potential to replace the standard DWI technique for special indications like DWI of the cerebellum and the brainstem or in presence of metallic implants or hemorrhage.
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Investigative radiology · Jun 2009
Magnetic resonance imaging detects intestinal barrier dysfunction in a rat model of acute mesenteric ischemia/reperfusion injury.
To develop an in vivo intestinal permeability assay applying magnetic resonance imaging (MRI) to monitor real-time gut barrier defects in animal models of acute mesenteric ischemia/reperfusion (I/R) insult. ⋯ This novel MRI-based intestinal permeability assay has shown a significant increase in the signal intensity in liver, kidney, and plasma samples that correlated with mucosal barrier defects in experimental models of acute mesenteric I/R.
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Investigative radiology · May 2009
Diffusion-weighted imaging as predictor of therapy response in an animal model of Ewing sarcoma.
To evaluate the potential of diffusion-weighted imaging (DWI) for monitoring dose-dependent tumor response in a mouse-xenograft model of Ewing sarcoma after administration of treosulfan in different dosages. ⋯ Compared with volumetric measurements, DWI of the viable tumor parts could be used to discriminate between the effects of 2 different dosages at an earlier time point than volumetric measurements in an animal model in vivo. This method could be especially useful for monitoring drug effects in phase I/II clinical trials.
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Investigative radiology · Apr 2009
Relationship between ventricular morphology and aqueductal cerebrospinal fluid flow in healthy and communicating hydrocephalus.
Differences in the magnitude of cerebrospinal fluid (CSF) volumetric flow through the cerebral aqueduct between healthy and hydrocephalic patients have been previously reported. However it is not clear whether this is directly related to the pathophysiology or secondary to altered ventricular morphology and hydrodynamics. This work aims to determine the role of anatomic and hydrodynamic factors in modulating the magnitude of CSF flow through the aqueduct. ⋯ Aqueductal CSF flow is strongly correlated with ventricular morphology, especially with the total ventricular volume and the third ventricle width, but not with the tested hydrodynamic parameters. In addition, ASV is linearly correlated with aqueductal lumen area, suggesting that the aqueductal CSF flow characteristics can be explained by oscillating pressure differences on the order of less than 0.01 mmHg. These findings may explain why a standalone ASV is a poor diagnostic marker and an insensitive indicator of shunt outcome in idiopathic normal pressure hydrocephalus.