Hyperacute Cerebral Enhancement: The Earliest Predictor of Hemorrhage by MR Imaging?

Abstract

A test to detect very early hemorrhage in acute cerebral infarct could offer a substantial increase in the safety and success of advanced stroke therapies, particularly when the use of thrombolytic therapies is contemplated. Currently, computed tomography is the standard test for the detection of cerebral hemorrhage but is not a valid predictor of potential areas of hemorrhagic transformation. A technique to evaluate the risk of hemorrhagic transformation in infarcted cerebral tissue has been conducted with contrast-enhanced magnetic resonance imaging in various animal stroke models. Knight demonstrated Gadolinium-DTPA enhancement in the territory of occluded vessels immediately in rats after reperfusion. Gadolinium enhancement was thought to predict areas of hemorrhagic transformation. Yenari and associates demonstrated in rabbit models that contrast-enhanced T1-weighted scans can reveal regions of blood-brain barrier disruption, characterized as hemorrhagic transformation in ischemic tissue. The authors report a clinical example in which hyperacute contrast-enhanced magnetic resonance imaging was the first indication of hemorrhagic transformation within 24 hours of onset of an acute cerebral infarct.

Prediction of Hemorrhagic Transformation After Thrombolytic Therapy of Clot Embolism

“…In a human case report, Gd-DTPA contrast enhancement in T1-weighted images also correlated with HT, determined by a CT scan at a later time point. 25 However, these findings do not necessarily indicate the possibility of detecting tissue at risk of HT before bleeding occurs or before reperfusion is initiated.…”

“…24,25 Nevertheless, studies that combine this method of contrast-enhanced MRI with the evaluation of the risk of hemorrhagic complications are rare. Yenari et al 26 demonstrated in a rabbit model that contrast-enhanced scans can reveal regions of BBB disruption in the presence of HT.…”

MR image features predicting hemorrhagic transformation in acute cerebral infarction: a multimodal study

“…MR-based neuroimaging techniques have been used in the early detection of acute hemorrhage for more than a decade [10][11][12][13][14][15] and have been shown to be more sensitive and accurate in detecting early changes of HT than other neuroimaging techniques, such as computed tomography (CT) [16][17][18]. The versatilities of different MR imaging modalities have demonstrated their superb capacities in revealing the indicators and biomarkers and in assessing the extent, severity, and associations of the HT.…”

Verification of Enhancement of the CSF Space, not Parenchyma, in Acute Stroke Patients with Early Blood—Brain Barrier Disruption

“…Although past studies have suggested that the location of HARM is in the CSF (Dechambre et al, 2000;Koenigsberg et al, 1999;Latour et al, 2004;Warach and Latour, 2004), the verification of CSFbased HARM versus involvement of the parenchymal space has yet to be performed. Accurate differentiation between CSF and parenchyma is needed to assess the relative contributions of each population to the HARM enhancement.…”

“…After the development of intravenously administered contrast agents such as Gd-DTPA (gadoliniumdiuethylene triamine penta-acetic acid), T 1 -weighted contrast-enhanced magnetic resonance imaging has been employed for the assessment of blood-brain barrier (BBB) integrity in experimental (Dijkhuizen et al, 2001;Kastrup et al, 1999;Runge et al, 1994) and clinical stroke (Elster and Moody, 1990;Koenigsberg et al, 1999;Merten et al, 1999). Gd-DTPA does not readily cross an intact BBB; thus, the presence of image enhancement post-contrast enables the identification of BBB disruption.…”