MRA Suitable for Evaluation of Occlusion and Stenosis
The current issue of Radiology includes an article which describes use of high-spatial resolution contrast-enhance MR angiography (MRA) with time-resolved data for the detection of occlusion. Additional benefits of this approach include increased radiologist confidence. An additional benefit is that the proposed approach does not extend study reading time.
The research, completed by a team from Duke University Medical Center, entailed retrospective examination of images from 27 patients who all were examined with gadolinium-enhanced MRA chest imaging for central vein evaluation. Images were procured with either a 1.5 or 3 Tesla MR system.
Six radiologists completed three different sessions to review images procured: one view of only MIP, one of images with high spatial resolution source, and the final session incorporated both sets of images. The difference in time to assess the three different sets was negligible.
Sensitivity of occlusion detection was increased among the time-resolved MIP images, the difference in sensitivity was more profound among resident radiologists examining films. These images also had a higher rate of specificity with respect to occlusion detection. Interestingly, the highest rate of reader confidence was found with the combined image assessment.
Time-resolved MIP (maximum intensity projection) MR images can be captured quickly in short time intervals. This supports assessment of temporal dynamics of blood flow. Another advantage of time resolved data sets is that they employ less contrast material compared to conventional high spatial resolution MRA.
Primary advantages associated with use of this technique include dynamic visualization of venous blood flow. Images are similar to that produced with conventional angiography. The approach allows visualization of collateral veins that are enlarged which are hallmarks of chronic venous stenosis and occlusions.
May 19, 2008 Related topics: Imaging, Diagnostic, Radiology