MRI diffusion-weighted imaging in intracranial hemorrhage (ICH)

Diffusion-weighted signal patterns of intracranial haemorrhage

“…Hyperacute blood clot, however, demonstrates increased T2-weighted and FLAIR signal, which is attributed to retraction of the clot matrix and changes in protein concentration, among many proposed theories. 1,8,24,25 Multiple authors have reported the characteristic presence of a T2-hypointense rim around the periphery of a hyperacute intraparenchymal haematoma, representing early transition to the deoxyhaemoglobin state in the relatively low oxygen tension environment at the periphery of these haematomas. 14e16 As described by Kang et al, 7 DW images of hyperacute haematomas demonstrate central hyperintensity representing diamagnetic oxyhaemoglobin and a peripheral hypointense rim representing early conversion to paramagnetic deoxyhaemoglobin.…”

“…In hyperacute and late subacute haemorrhage, therefore, the DW signal is free of significant T2* effects and is instead largely determined by what may represent true restricted diffusion and the intrinsically long T2 time of such haematomas. 1,7,13 Relationship of location and environment to blood-product evolution A few location-specific factors that can affect the temporal evolution of blood merit additional consideration when analysing the MRI signal pattern of haemorrhage, including its DW signal: oxygen tension, the presence of tissue macrophages, and the concomitant presence of tumour cells.…”

Contribution of diffusion-weighted imaging to conventional MRI for detection of haemorrhagic infarction in ovary torsion

“…It is well known that torsion causes cytotoxic oedema, and hence leads to restricted diffusion on DWI in ovary stroma [ 19 ]. Meanwhile, it is a reality that blood products have magnetic susceptibility effect on DWI, as in early haemorrhagic infarction or haematomas of the brain that strongly reduces diffusion of water with the resultant low ADC values, even lower than non-haemorrhagic acute infarcts [ 20 , 21 ]. Therefore, we suggest that haemorrhagic infarction of ovary may cause a further drop of ADC values than non-haemorrhagic ones, as shown in the present study.…”

“…DWI in cerebral parenchymal haemorrhagia reveals a strong hyperintense signal in hyperacute and late subacute stages, and a strong hypointense signal in acute and early subacute stages. ADC values in hyperacute, acute and early subacute stages of parenchymal haemorrhagia as well as haemorrhagic infarcts were reported to be clearly lower than non-haemorrhagic ischemic stroke [ 20 , 21 ].…”

Diffusion-Weighted Imaging of the Brain: Beyond Stroke

“…The differential diagnosis for this phenomenon comprises a variety of conditions with marked T2 hypointensity from abnormal iron deposition to various infectious, inflammatory and neoplastic processes, and thus clinical context is imperative for accurate interpretation [45]. Although DWI has proven to be accurate in the staging and identification of hemorrhagic infarctions of both arterial and venous origin, its accuracy in the setting subarachnoid hemorrhage appears to be low [46].…”