ABSTRACT
The signal pattern of intracranial haemorrhage on diffusion-weighted imaging (DWI) as it evolves over time is rarely discussed due to the sensitivity of T2*-weighted sequences and the specificity of classic signal patterns on T1 and T2-weighted sequences. The DWI signal is strongly affected by the magnetic susceptibility of paramagnetic blood products and, therefore, is markedly hypointense in the same phases that demonstrate hypointensity on T2*-weighted sequences; however, hyperacute haemorrhage (oxyhaemoglobin-predominant clot) and late subacute haemorrhage (extracellular methaemoglobin) do not demonstrate T2* hypointensity. Moreover, T2*-weighted sequences are less sensitive to the presence of extra-axial haemorrhage than to intraparenchymal haemorrhage. At these stages of evolution, haemorrhage demonstrates high DWI signal in association with low ADC values, which may be more pronounced than even its corresponding fluid-attenuated inversion recovery (FLAIR) signal. DWI is useful for identifying hyperacute subarachnoid haemorrhage and as a problem-solving tool in challenging cases.
Subject(s)
Diffusion Magnetic Resonance Imaging/methods , Intracranial Hemorrhages/diagnosis , Acute Disease , Humans , Sensitivity and SpecificityABSTRACT
To evaluate the role of imidazolidinone moiety of potential anticancer 4-phenyl-1-arylsulfonylimidazolidinones 1 for their cytotoxicity, conformationally similar 4-phenyl-2-arylsulfonylaminooxazolines 2 were synthesized and compared their cytotoxicities with those of the corresponding 1. Compounds 2 showed much reduced activity compared to N-arylsulfo-nylimidazolidinones 1. This result might indicate that the imidazolidinone ring of 1 have the other roles for the activity as an essential structural motif in addition to conformational contribution.
