Investigative radiology
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Investigative radiology · Jan 2001
Comparative StudyReview of studies establishing the aging male spontaneously hypertensive rat as a detector and quantifier of the kidney toxicity of radiocontrast media and other chemicals.
There is a need for practical and sensitive preclinical tests for detecting the kidney toxicity of chemicals. The spontaneously hypertensive rat (SHR), as it ages, develops renal and cardiovascular changes similar to those considered as human risk factors for radiocontrast-induced renal damage. Age, male gender, and uncontrolled hypertension make these animals susceptible to the volume and osmolality of the administered contrast agent and the effect of repeated contrast administration after a brief interval. This article reviews studies in which the role of these and other factors were evaluated to validate the male SHR as a small animal model for renal damage induced by contrast and other agents. ⋯ The results indicate that the aging male SHR develops spontaneous renal lesions that progress with age, increasing the susceptibility to the renal-damaging effects of contrast. Thus, the aging male SHR provides a laboratory tool for detecting the risk of renal damage of new contrast media as well as other pharmaceuticals and assessing methods to protect the kidneys and possible mechanisms of renal damage.
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Investigative radiology · Apr 2000
Lobar distribution of emphysema in computed tomographic densitometric analysis.
The aims of this study were to determine the extent of emphysema in individual lobes and to investigate whether the lobar distribution of emphysema influences pulmonary function. ⋯ CT densitometry showed a distinct lobar distribution of emphysema. Pulmonary function is significantly different between predominantly upper- and lower-lobe emphysema groups.
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Investigative radiology · Apr 2000
Assessment of the vascularization of neuroendocrine tumors by stimulated acoustic emission of SH U 508A ultrasound contrast agent and color or power Doppler sonography.
To assess the vascularization of neuroendocrine tumors by stimulated acoustic emission (SAE) of SH U 508A during the blood pool phase in comparison with contrast-enhanced Doppler sonography. ⋯ Blood pool SAE failed to determine subtle tumor perfusion correctly. The rating score for contrast-enhanced Doppler sonography characterized tumor perfusion with high accuracy. The use of a contrast agent significantly improved perfusion characterization.
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Investigative radiology · Mar 2000
First experiences in using a new ultrasound mode and ultrasound contrast agent in the diagnosis of blunt renal trauma: a feasibility study in an animal model.
To evaluate the diagnostic value of the new ultrasound mode "wide-band harmonic" (WBH) using an ultrasound contrast agent in blunt renal trauma in an animal model. ⋯ Only 20% of the experimental subjects developed parenchymal lesions with diameters of 1.0 mm or larger. All these lesions were identified only using WBH. These results indicate the potential to use WBH plus contrast for the diagnosis of blunt renal trauma.
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Investigative radiology · Sep 1998
Comparative StudyContrast-enhanced magnetic resonance angiography of cerebral arteries. A review.
The loss of blood vessel visibility due to the signal saturation of slow flow can be partially overcome by the T1 reduction that occurs with the use of contrast agents such as Gd-DTPA during magnetic resonance angiography (MRA) studies. Dynamic-imaging techniques that have been applied successfully in abdominal imaging may also be useful for intracranial applications. However, the time between arterial and venous enhancement is very short during intracranial circulation. ⋯ Knowledge of the contrast-agent dilution factors and the ultimate resulting relaxation rates can be used to optimize the imaging parameters to maximize vessel signal relative to the background signal (the signal-difference-to-noise ratio). The additional venous vascular detail in the contrast-enhanced study can be spatially resolved in the 3D image data and determined by incorporating information from both high-resolution precontrast and postcontrast studies. In this article, the history, development and application of contrast agents in MRA are presented.