PURPOSE: We evaluated the MRI finding of pachymeningeal enhancement in patients with intracranial hypotensionand head trauma with particular attention to differential findings and change in follow-up study, and in order tosupport the knowledge about the pathophysiology of dural enhancement. METHODS AND MATERIALS: The findings ofenhanced brain MRI of fifteen patients who showed diffuse pachymeningeal enhancement were retrospectivelyexamined. Seven of fifteen patients were finally diagnosed as spontaneous intracranial hypotension(SIH). Eight offifteen patients had a recent history of head trauma. We analyzed the shape, thickness, continuity and extent ofdural enhancement, and the others concerned with positive MR findings. We also analyzed findings suggesteddisplacement of brain parenchyma- displacement of the iter and cerebellar tonsil, and flattening of the anterioraspect of the pons-. Four of seven patients with SIH and four of eight patients with head trauma, underwentfollow-up MRI. In the follow-up study, the presence of resolving pachymeningeal enhancement and symptomimprovement was investigated. RESULTS: In all cases of SIH, the dura showed diffuse, even 3(1mm thick, global andcontiguous enhancement along both cerebral convexities, both tentoria, and the falx. Displacement of the iter wasnoted in six cases and flattening of the anterior aspect of the pons in five. Displacement of the cerebellartonsil was noted in one case. Five of seven cases showed small amount of subdural fluid collection. In all casesof head trauma, the dura was enhanced diffusely and asymmetrically, and showed no contiguity. Its distribution wasconsistent with the locations of traumatic lesions. Displacement of the iter was noted in one case. In four casesof SIH, clinical symptoms had improved, and three showed complete resolution of dural enhancement, in one patientcontinuously showed partial dural enhancement. Four cases of head trauma showed complete resolution of duralenhancement. CONCLUSIONS: Reversible diffuse pachymeningeal enhancement and additional findings in brain MRI ofSIH and head trauma are valuable for differenciation from other irreversible pathological conditions related topachymeningeal enhancement and to support the knowledge about pathophysiology of dural enhancement.