Radhakrishnan Ravikumar MD, PhD, Presenter: Nothing to Disclose

General Leung, Abstract Co-Author: Nothing to Disclose

Susan Crisp, Abstract Co-Author: Nothing to Disclose

Robert Maggisano MD, Abstract Co-Author: Nothing to Disclose

Alan Rowland Moody MD, Abstract Co-Author: Nothing to Disclose

Quantitative assessment of haemodynamic vascular response of carotid arteries (proximal and distal) to stenosis, using dynamic contrast enhanced MRI.

58 patients (32 men and 26 women) with unilateral carotid disease of varying grades of stenosis (< 50% to complete occlusions) underwent routine brain imaging (T1,T2 and Proton density) and MR angiographic (Time of Flight, Phase contrast and CE-MRA) evaluation. Both carotid arteries were reviewed. A single observer recorded all the measurements using a Quantitative functional assessment tool (GE AW, USA). The measurements included areas of internal and common carotid arteries, % stenosis with respect to the normal side from MRA and haemodynamic measurements using the Positive Enhancement Integral (PEI). PEI was calculated from a dynamic contrast enhanced acquisition (obtained at the level of the common carotids proximal to stenosis) by placing a circular region of interest (ROI) over the entire area of the enhanced carotid arteries. The integral of the area under the enhancement curve was used as the measure of PEI.

The ratios (abnormal to normal side) of the area under the enhancement curve, areas of internal and common carotid arteries decreased with increasing % stenosis with significant changes noted in patients with >70% stenosis. Cross flow was seen in 79% of patients with >70% stenosis and nearly all patients with near total and complete occlusions in our group had presence of cross flow.

Focal luminal narrowing within the internal carotid artery causes haemodynamic flow abnormalities leading to progressive negative vascular remodeling both proximal and distal to the stenosis. The presence or absence of cross flow especially with stenosis >70% may help determine a subgroup of patients who need to be aggressively monitored and treated.

Imaging of haemodynamic effects of carotid stenotic disease and end organ (brain) changes may provide information regarding evolution of cerebral ischaemic disease.

Ravikumar, R, Leung, G, Crisp, S, Maggisano, R, Moody, A, MRI Assessment of Progressive Negative Vascular Remodeling and Haemodynamic Changes in Patients with Carotid Artery Stenosis.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5009601.html