Intracerebral hemorrhage (ICH) remains a devastating diagnosis with high morbidity. Hematomal volume has been suggested as a major factor influencing patient functional outcome as has hyperglycemia, coagulation status and statin use. Growing interest has been focused on peri-hematomal edema (PHE) in intracerebral hemorrhage, believing it to be a different entity then the more familiar post ischemic stroke edema, in hopes of better understanding its clinical significance. A recent paper in Stroke looked at the natural history of peri-hematomal edema using MRI. They found that it increased most rapidly in the first 2 days after symptoms and peaked towards the end of the 2nd week, a different time course than edema ischemic stroke, but they were unable to draw any conclusions regarding impact on 3-month functional outcome. Subsequent studies provided conflicting results regarding the validity of changes seen on MRI in predicting true cerebral edema. If PHE is to be a target of further research, we must have a reliable imaging definition.
“Measurement of Peri-hematomal Edema in Intracerebral Hemorrhage” by Urday et al. introduces computed tomography (CT) technology to the discussion. Their study included 20 subjects >18yo with primary spontaneous supratentorial ICH confirmed by CT. 18 subjects with both CT and MRI performed in close association were also included. Two blinded independent raters then measured PHE on the 20 patient’s baseline and 24hr post ICH CT scans. Their measurements were reviewed by two stroke neurologists. In defining PHE, it had to be more hypodense than the same region in the contralateral hemisphere and more hypodense immediately around the hemorrhage area to rule out inclusion of other entities such as remote infarcts.
Intrarater/Interrater reliability was found to be excellent at both baseline and 24hr post ICH. There was one outlier that corresponded to a 118cc frontal lobe hemorrhage suggesting that PHE in large hemorrhages are more difficulty to approximate. PHE volumes in the 18 subjects with both CT and MRI imaging available also did not differ.
The possibility of using CT imaging to reliably approximate peri-hematomal edema moves us one step closer to developing effective treatment strategies. CT is quicker to obtain, more widely available and still more cost effective than MRI imaging. It is also the imaging method of choice when evaluating an acute bleed. Where do we go from here? Larger numbers are needed to confirm the investigator’s findings but perhaps this will open the door to more clinical trials targeting inflammation/edema in hopes of improving a once dismal outlook.