What does this mean The marrow signal is within normal limits. The midline structures are unremarkable. No restricted diffusion to suggest acute infarct. The brain parenchyma demonstrates normal signal characteristics. The ventricles are normal in size and configuration. No extra-axial collections or mass effect. No foci of abnormally low gradient signal involving the brain parenchyma. The basal cisterns are patent. The expected skull base flow voids are preserved. The tympanomastoid cavities, the Meckel s caves, the orbits are unremarkable. Scattered mucosal thickening in the bilateral maxillary sinuses and ethmoid air cells. No parenchymal hematoma.