High spatial and temporal resolution imaging of the arterial vasculature of the lower extremity with contrast enhanced MR angiography

High temporal and spatial resolution imaging of peripheral vascular malformations

PURPOSE

To assess the performance of a recently developed 3D time-resolved CE-MRA technique, Cartesian Acquisition with Projection-Reconstruction-like sampling (CAPR), for accurate characterization and treatment planning of vascular malformations of the periphery.

MATERIALS AND METHODS

Twelve patient studies were performed (eight female, four male; average age, 33 years). The protocol consisted of three-dimensional (3D) time-resolved CE-MRA followed by a single late phase T1-weighted acquisition. Vascular malformations were imaged in the forearm, hand, thigh, and foot. Imaging evaluation was performed for accurate characterization of lesion type, identification of feeding and draining vessels, involvement with surrounding tissue, overall quality for diagnosis and treatment planning, and correlation with conventional angiography.

RESULTS

Time-resolved CE-MRA allowed for characterization of malformation flow and type. Feeding and draining vessels were identified in all cases. Overall quality for diagnosis and treatment planning was 3.58/4.0, and correlation with conventional angiography was scored as 3.89/4.0.

CONCLUSION

The CAPR time series has been shown to portray the temporal dynamics and structure of vascular malformations as well as the normal vasculature with high quality. CAPR time-resolved imaging is able to accurately characterize high and low flow lesions, allowing for pretreatment lesion assessment and treatment planning. Delayed imaging is important to capture complete filling of very slow flow vascular malformations.

Imaging atherosclerosis in HIV: carotid intima-media thickness and beyond

Chronic immune activation and inflammation are associated with an increased risk of atherosclerosis in HIV-infected patients. In this review, we discuss the role of established and novel imaging modalities to define more accurately the structure and function of inflammation-mediated atherosclerosis in the context of HIV. Historically, carotid ultrasound studies were the first to show higher rates of subclinical atherosclerosis in HIV-infected subjects versus uninfected controls. However, computed tomography is the noninvasive gold standard for imaging the coronary arteries, and studies in HIV suggest a higher prevalence of noncalcified plaque. Endothelial dysfunction can be quantified by measuring flow-mediated brachial artery dilation by ultrasound and has been used extensively in antiretroviral switching trials and small pilot trials of therapeutics to assess cardiovascular risk in this population. In the future, novel imaging modalities such as intracoronary optical coherence tomography, positron emission tomography imaging of (18)F-fluorodeoxyglucose uptake, and molecular-targeted magnetic resonance imaging will characterize the burden of vulnerable plaque and other unique features of inflammatory atherosclerosis in HIV.