Organized Chronic Subdural Hematoma: A Condition Presenting Mixed-Density Hematoma without Gradation Density on Brain CT

Organized chronic subdural hematoma is a neurological condition characterized by organized clot formation inside the hematoma. Unlike nonorganized chronic subdural hematoma with persistent bleeding inside, organized subdural hematoma is often a nonurgent condition that does not require emergency drainage, unless progressive cerebral compression with neurological disturbances is present. However, as the CT values in organized clot formation and active bleeding fall in similar ranges, distinguishing these 2 conditions with different emergency levels based on brain CT alone is sometimes difficult. Here, we describe the case of a 78-year-old man with persistent nocturia who was referred to our hospital. He had a history of head trauma on the left side about 1 year ago, followed by neurosurgery at another hospital. Brain CT revealed a multiseptated subdural space and a mixed-density hematoma without gradation density on the contralateral side of the past head trauma region. Based on the lack of progressive neurological disturbances and the absence of gradation density in CT values inside the hematomas, his condition was judged as nonurgent, and emergency drainage was spared. One year after his first visit to our hospital, the patient experienced a normal life without any neurological disturbances, except for nocturia. The absence of gradation density in CT values along the gravity direction inside the organized hematoma may be a clue to estimate nonurgency without persistent active bleeding inside.