Type C Positive recommendation, based on strong consensus of Class III evidence. Type D Negative recommendation, based on inconclusive or conflicting Class II evidence. Type E Strong negative recommendation, based on evidence of ineffectiveness or lack of efficacy, based on Class I or Class II evidence. CT indicates computed tomography. Petechial refers to scattered hyperdense points, coalescing to form irregularly hyperdense areas with hypodense interruptions.
Hematoma refers to a solid, homogeneously hyperdense image.
CT indicates computed tomography, and HU, Hounsfield units. Proton density and T2 images may be acquired with a fast spin-echo series. If gadopentetate dimeglumine is to be administered, MRA should be performed before contrast injection. Slice thickness should measure 5 mm at most. MRI indicates magnetic resonance imaging, and MRA, magnetic resonance angiography.