Dynamic contrast-enhanced MR imaging may be a useful imaging method and Ktrans may prove to be an imaging marker for the assessment of the therapeutic response of the vasa vasorum in patients with atherosclerotic plaque. PurposeTo investigate whether short-term, intensive lipid therapy leads to changes in microvascular characteristics, as measured by using dynamic contrast material–enhanced (DCE) magnetic resonance (MR) imaging.Materials and MethodsInstitutional review board approval and informed consent were obtained for this HIPAA-compatible study. Subjects with established coronary artery disease or carotid artery stenosis of 15% or greater determined by using ultrasonography and with levels of apolipoprotein B of 120 mg/dL (1.2 g/L) or greater were enrolled in an ongoing study (clinical trial NCT00715273). All received intensive lipid therapy to achieve targeted high- and low-density lipoprotein cholesterol levels and underwent serial serum monitoring including high-sensitivity C-reactive protein (HsCRP) level measurements. Carotid artery MR imaging examinations including morphologic and DCE MR images were obtained at baseline and 1 year after treatment. In subjects with advanced lesions (>2 mm thick), MR image analys...

Liver magnetic resonance imaging (MRI) is subject to continuous technical innovations through advances in hardware, sequence and novel contrast agent development. In order to utilize the abilities of liver MR to its full extent and perform high-quality efficient exams, it is mandatory to use the best imaging protocol, to minimize artifacts and to select the most adequate type of contrast agent. In this article, we review the routine clinical MR techniques applied currently and some latest developments of liver imaging techniques to help radiologists and technologists to better understand how to choose and optimize liver MRI protocols that can be used in clinical practice. This article covers topics on (I) fat signal suppression; (II) diffusion weighted imaging (DWI) and intravoxel incoherent motion (IVIM) analysis; (III) dynamic contrast-enhanced (DCE) MR imaging; (IV) liver fat quantification; (V) liver iron quantification; and (VI) scan speed acceleration.

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Background and Purpose—: Autopsy studies have suggested a relationship between intraplaque hemorrhage (IPH) and vasa vasorum, which arise primarily from the adventitia. Adventitial vasa vasorum can be characterized in the carotid arteries by estimating perfusion parameters via dynamic contrast-enhanced MRI. The purpose of this investigation was to use dynamic contrast-enhanced MRI to test in vivo in a clinical population whether adventitial perfusion, indicative of vasa vasorum microstructure, is associated with IPH. Methods—: Symptomatic patients with carotid plaque ipsilateral to the ischemic event underwent bilateral carotid artery MRI examination, which included multicontrast sequences for detecting IPH and a dynamic contrast-enhanced MRI sequence for characterizing adventitial perfusion. Kinetic modeling of the dynamic contrast-enhanced MRI time series was performed to estimate adventitial v _p (fractional plasma volume, reflecting local blood supply) and K ^trans (transfer constant, reflecting vessel surface area, and permeability). Results—: From the 27 patients (22 men; 69±10 years of age) recruited, adventitial perfusion parameters were obtained in 50 arteries. The presence of IPH was associated with a significantly higher value in adventitial K ^trans (0.142±0.042 vs 0.112±0.029 min ⁻¹ ; P <0.001) but not in v _p (0.163±0.064 vs 0.149±0.062; P =0.338). This relationship remained after adjusting for symptomatic status, degree of stenosis, and other confounding factors. Conclusions—: This study demonstrated an independent pathophysiological link between the adventitia and IPH and related it to the microstructure of adventitial vasa vasorum. Adventitial perfusion imaging may be useful in studying plaque pathogenesis, but further examination through prospective studies is needed.