Susceptibility-weighted imaging (SWI) is a powerful tool for characterizing infarctions in patients earlier and directing more prompt treatment, according to a study presented last week at the annual meeting of the American Roentgen Ray Society (ARRS) in Chicago.
Conducted at the University of California, Irvine, the study involved an investigation of 35 patients with thromboembolic infarctions. SWI detected thromboemboli in 30 of these patients. A total of 14 of these thromboemboli were located in arteries other than the anterior division of the middle cerebral artery (MCA).
Mark D. Mamlouk, MD, the study’s lead author, notes that while SWI has traditionally been used as a secondary tool to evaluate intracerebral hemorrhages and to detect clots with middle cerebral artery infarctions, the study results clearly demonstrate additional applicability. In cases where there is a suspicion of stroke, he explains, physicians can add the SWI sequence as part of the MRI brain protocols. This enables them to better characterize the origin of the stroke. "At our institution, we are amazed at how often SWI detects thromboemboli in all major cerebral arteries, not just the MCA,” Mamlouk notes. “Given SWI's high sensitivity (86%) of thromboemboli detection, we found that there is an adjunctive role of SWI in classifying cerebral infarctions in patients."
Although MRIs have been the gold standard for evaluating infarctions, Anton Hasso, MD, senior author of the study, notes that adding SWI to the routine MRI sequences for evaluating patients with a clinical suspicion of stroke will hasten their time to treatment and improve overall recovery. Mamlouk concurs. "The utility of SWI extends beyond the evaluation of hemorrhage,” he says. “Using SWI in patients with cerebral infarctions will decrease further imaging and its associated costs and radiation exposure, but more importantly, this imaging technique will guide direct management in a timelier manner."