Diffusion-weighted imaging of traumatic subdural hematoma in the subacute stage.

Five cases of traumatic subdural hematomas in the subacute stage (from 7 to 20 days after head injury) were treated in one male and four females, aged from 63 to 82 years, with evacuation via craniotomy in three and aspiration via burr hole surgery in two. All hematomas were evaluated by T1-, T2-, and diffusion-weighted magnetic resonance imaging, and measurement of the apparent diffusion coefficient (ADC). Diffusion-weighted imaging showed the hematoma as a crescent high intensity area with a low intensity rim close to the brain surface (two-layered structure) in four cases and as high intensity with low intensity components in one case. The high intensity areas under the dura mater on diffusion-weighted imaging appeared as homogeneous high intensity on T1- and T2-weighted imaging in four cases, and inhomogeneous high intensity on T1- and isointensity on T2-weighted imaging in one case. The mean ADC value of the high intensity areas was 0.58 +/- 0.23 (mean +/- standard deviation) x 10(-3) mm2/sec. The operative findings revealed the high intensity areas as solid clots. The low intensity areas on diffusion-weighted imaging appeared as homogeneous high intensity in four cases and inhomogeneous isointensity with high intensity components in one case on T1- and T2-weighted imaging. The mean ADC value of the low intensity areas was 2.03 +/- 0.27 x 10(-3) mm2/sec. The operative findings revealed the low intensity areas as mixtures of resolved clot and cerebrospinal fluid. Diffusion-weighted imaging showed the characteristic two-layered structure in traumatic subdural hematomas in the subacute stage, and analysis of the ADC values was useful for differentiating solid from liquid hematoma and for selection of the surgical procedure.

Diffusion-weighted magnetic resonance imaging of organized subdural hematoma--case report.

A 59-year-old male presented with a left organized subdural hematoma. The hematoma appeared as a homogeneous low density area on brain computed tomography and as hyperintense and isointense area on both fluid-attenuated inversion recovery and T2-weighted magnetic resonance (MR) imaging. Echo-planar diffusion-weighted MR imaging showed a crescent hyperintense area under the dura mater and an irregular hypointense area over the brain surface in the left subdural space. The apparent diffusion coefficient (ADC) values of the solid and liquid hematoma were 0.86 +/- 0.32 x 10(-3) and 2.56 +/- 0.39 x 10(-3) mm2/sec, respectively. The ADC value of the solid hematoma was similar to acute subdural or intraparenchymal hematoma, and that of the liquid was similar to cerebrospinal fluid. Burr-hole surgery failed to remove all the hematoma, and he complained of persistent headache. The hematoma was removed through a craniotomy without further neurological deficits. Organized subdural hematoma often requires craniotomy for evacuation because of its solid content. Diffusion-weighted MR imaging and measurement of ADC values can differentiate solid from liquid hematoma, so are useful for selection of the surgical procedure.

[Gamma knife radiosurgery for spontaneous carotid-cavernous sinus fistula (CCF)].

Gamma knife radiosurgery was carried out for spontaneous CCF (carotid-cavernous sinus fistula) in 8 patients (1 male and 7 females), and its results were reported. The ages ranged from 48 to 74 years with a mean of 60.6 years. As initial treatment before radiosurgery, embolization was carried out except in one patient, and radiotherapy was used in two patients. Six patients were in the category of Barrow's type D, and two patients were in the category of Barrow's type B. As it contained the fistula, the lateral wall of the cavernous sinus was irradiated with 8-14.5 Gy (mean 10.8 Gy). As a result, complete obliteration of CCF was confirmed by DSA in seven of the eight patients between 6 and 18 months after radiosurgery. There were no side effects observed during a follow-up period of 8 to 116 months. Although the main treatment for spontaneous CCF is intravascular surgery at present, gamma knife radiosurgery is a useful adjuvant treatment for the residual CCF after embolization.