Diffuse pachymeningeal enhancement on magnetic resonance (MR) imaging is important in identifying spontaneous and secondary intracranial hypotension (IH) [cerebrospinal fluid (CSF) hypovolemia] in patients with postural headache, because CSF pressure at lumbar puncture is variable. We examined the pachymeningeal enhancement pattern in patients with IH. MR imaging findings of pachymeningeal enhancement were examined before and after treatment in seven consecutive patients with spontaneous IH and one patient with IH after lumbar puncture. Diffuse non-nodular dural enhancement was observed in all patients. Characteristic thick, uninterrupted, enhancement was observed, mainly in the dura of the frontal, temporal, and retroclival regions, and the tentorium. Thin and uninterrupted, or partially interrupted, enhancement was observed, mainly in the parieto-occipital region and cerebellar convexity. Curved linear enhancement was observed along the calvarium of all patients. A wave-like appearance, a clear pattern of dural unevenness parallel to the brain, was detected in the frontal and temporal regions, near the base, in all patients. A wave-like appearance, especially in the frontal and temporal base, may be a characteristic MR imaging indicator of IH.