What is considered a significant midline shift on a CT scan of the brain, and what are its clinical implications?

A significant midline shift is defined as a shift greater than 5 mm. Key diagnostic features include displacement of the septum pellucidum and compression of the lateral ventricles. Clinically, this can indicate increased intracranial pressure and potential herniation, requiring urgent intervention. Common pitfalls include mistaking asymmetrical ventricular size for shift, so always correlate with clinical findings.