Imaging technique may improve diagnosis of brain clots

Neuroradiologists at the University of Cincinnati College of Medicine in Ohio have found that specialized contrast-enhanced techniques combined with standard MRI scans could result in improved detection of venous blood clots in the brain.

Accurately diagnosing venous thrombosis is often difficult because it evolves over time, and recanalization — blood flowing through tiny channels in the clot — can alter its appearance. The blockages can decrease blood flow to the brain, resulting in death, a stroke or severe headaches. Improved imaging would allow doctors to diagnose the condition earlier and to prescribe treatments such as an anticoagulation drug.

In the April issue of the American Journal of Neuroradiology, lead researcher Dr. James L. Leach reported that images of partially recanalized dural sinus thrombosis were taken by MR, time-of-flight MR venography (TOF-MRV), which does not require a contrast agent, and elliptical centric-ordered contrast-enhanced MR venography (CE-MRV), which uses a contrast agent.

This image of a contrast-enhanced MR venogram shows areas of restored blood flow (arrows) and areas of persistent blood clot (arrowheads). Reprinted with permission of the American Journal of Neuroradiology. Nine patients with cerebral thrombosis had MR images taken with a 1.5-T scanner from GE Healthcare, and one patient with the condition was imaged with a 0.3-T scanner from Hitachi. Nine underwent MR venography. Six were imaged with both TOF-MRV and CE-MRV, and three, with TOF-MRV only. A total of 34 thrombosed venous segments were identified in the study pool.

The researchers found that all readings taken with the TOF-MRV and CE-MRV techniques detected abnormalities, and images taken with CE-MRV provided a superior characterization of thrombosed regions. The technique also allowed researchers to identify areas where blood flow had been partially re-established.

They also found that the appearance of the clot did not change in follow-up imaging, done on average 13.6 months later. Because the study was done on a very select study group, further research is needed to determine whether the findings are typical for all cases of chronic, partially recanalized sinus thrombosis.