Hyperattenuated

We measured the length of hyperattenuated arterial obstructions on non-contrast CT. We calculated HU ratios for each patient to assess attenuation of the obstruction in relation to normal background intra-arterial attenuation as: mean obstruction HU ÷ mean normal vessel HU. We repeated obstruction attenuation measurements, in the same location, on follow-up non-contrast CT. We calculated change in attenuation of the obstruction between the two scans.