Susceptibility-weighted MRI (SWI) is better than the current method of choice, T2-weighted gradient-recalled-echo (GRE) MRI, at detecting microhemorrhages on the brain—and it’s best to deploy the imaging technology as soon after injury as possible.
A new study in Radiology confirms SWI’s suspected superiority over GRE for diagnosing cerebral microbleeding as uncovered in a retrospective analysis of 603 members of the U.S. military who suffered traumatic brain injury (TBI) and were treated at Walter Reed National Military Medical Center.
Lead author Wei Liu, DSc, of the National Capital Neuroimaging Consortium in Bethesda, Md., and colleagues found that, using SWI, radiologists were able to detect 585 microhemorrhages in 37 patients—some 62 percent more than the 362 microhemorrhages they detected on GRE images.
In addition, 451 of the 585 microhemorrhages (77 percent) appeared more conspicuous in SWI images than in GRE images.
SWI uses a GRE pulse sequence, but it manipulates magnitude data and phase information in a way that yields high-specificity images of venous blood, hemorrhage and iron deposits.
Iron deposits are key to diagnosing microbleeds, but the deposits change over time, making it more difficult to detect microbleeding—which is where the need for speed comes in.
In the study, cerebral microhemorrhage showed up in 24 percent of military personnel who were imaged within three months post-injury.
In those imaged more than a year later, the figure was only 5.2 percent.
RSNA, publisher of Radiology, notes in a press release that cerebral microhemorrhages occur as a direct result of TBI and can lead to severe secondary injuries such as brain swelling or stroke.
According to CDC’s National Center for Injury and Prevention Control, about 1.7 million people in the U.S. sustain a TBI each year.
Meanwhile, the Institute of Medicine reports that 20 to 23 percent of military service members deployed to Afghanistan and Iraq have sustained TBI while serving.
Study co-author Gerard Riedy, MD, PhD, chief of neuroimaging at the National Intrepid Center of Excellence at Walter Reed, notes that TBI is a problem for not only directly affected servicemen and servicewomen, but also their families.
“We found that many of those who have served and suffered this type of injury were not imaged until many, many months after injury occurred, resulting in lower rates of cerebral microhemorrhage detection, which delays treatment,” Riedy said in prepared remarks. “We believe that having access to MRI in the field would facilitate early detection of TBI, thus providing timely treatment.”