J Korean Radiol Soc.  1994 Feb;30(2):219-224.

Chronic Subdural Hematoma Secondary to Traumatic Subdural Hygroma

• Lee BH
• Kim PN
• Hong DH
• Lim HH
• Bae WK
• Kirn IY
• Lee KS

Abstract

PURPOSE
Sometimes chronic subdural hematoma can be developed following posttraumatic subdural hygroma. The purpose of this study is to investigate its incidence, the duration required for their conversion, and characteristic CT and MR findings of subdural hygroma and chronic subdural hamatoma.
MATERIALS AND METHODS
We studied 8 patients with persistent posttraumatic subdural hygroma which consquently developed chronic subdural hamatoma. The patients were examined with CT initially and foilowed-up with CT in 3 and MR in 5. We analyzed the location of the lesion, the change of the density or signal intensity, the change of the size, and the degree of enhancement and mass effect.
RESULTS
The duration required for the formation of hematoma was 48-166 days (mean, 76 days). The characteristic CT findings of subdural hygroma were a crescentric lesion with CSF density along the inner table without contrast enhancement. The mass effect was minimal. The CT findings of chronic subdural hematoma were higher density than that of hygroma in all cases, increase in thickness and size in 3 cases, and contrast enhancement along the inner membrane of the hematoma in 5 cases. The signal intensities of the subdural hygroma were identical to those of CSF on both T1 and T2 weighted images, whereas, those of chronic subdural hematoma were higher.
CONCLUSION
The increased signal intensity on T1 weighted MR images and increased attenuation or contrast enhancement of the lesion on CT may suggest the conversion of subdural hygroma into chronic subdural hematoma.

MeSH Terms

Hematoma
Hematoma, Subdural, Chronic*
Humans
Incidence
Lymphangioma, Cystic
Membranes
Subdural Effusion*