Search Results

You are looking at 1 - 4 of 4 items for :

  • Author or Editor: Wen-Chao Liu x
  • Journal of Neurosurgery x
Clear All Modify Search
Free access

Cheng-Siu Chang, Chun-Chao Chuang, Ming-Fan Wu, Wen-Shan Liu, Hsien-Tang Tu and Chuan-Fu Huang

Object

Most cases of tumor-related hemifacial spasm (HFS) are treated by open surgery. The authors report the effects of Gamma Knife surgery (GKS) on benign tumor–related HFS at a mean follow-up time of 84 months.

Methods

Between 2000 and 2011, 6 patients (5 women and 1 man) harboring single tumors of the cerebellopontine angle (4 meningiomas and 2 vestibular schwannomas [VSs]) and experiencing HFS underwent GKS as a primary treatment. The mean age of the patients at the time of radiosurgery was 52.7 years (range 45–60 years).

The patients' tumors lay within the radiosurgical target area. In the 4 cases of meningioma, the mean radiosurgical treatment volume was 5.3 cm3 (range 1.2–9.6 cm3), and the mean radiosurgical tumor margin dose was 14.1 Gy (range 12–18 Gy); in the 2 cases of VS, the treatment volume was 2.5 cm3 in 1 patient and 11.2 cm3 in the other, and the margin doses were 11.5 and 12 Gy, respectively. The mean duration of HFS symptoms was 15.5 months (range 3–36 months).

Results

The mean follow-up period was 84 months (range 40–110 months). Overall, 4 (66%) of the 6 patients experienced complete relief from HFS without medication after GKS and 1 patient obtained a good outcome. The mean time for improvement to be realized was 12.6 months (range 3–24 months). Only 1 patient failed to experience relief from HFS, and coincidentally, the tumor did not shrink in that case. In all 6 patients (100%), tumor growth was controlled at a mean follow-up of 56 months after GKS: in 5 patients the tumor had decreased in size and in the other patient the tumor size remained unchanged. No new neurological deficit was noted after GKS, and 1 patient with facial numbness reported improvement after tumor shrinkage.

Conclusions

Gamma Knife surgery appears to be effective in treating benign tumor–related HFS and in controlling tumor growth. A reduction in tumor volume is related to spasm improvement. Although a time latency for spasm relief is associated with GKS, minimal side effects are expected.

Restricted access

Chuan-Fu Huang, Shyh-Ying Chiou, Ming-Fang Wu, Hsien-Tang Tu, Wen-Shan Liu and Jim-Chao Chuang

Object

Cellular density is a major factor for change in the apparent diffusion coefficient (ADC). The authors hypothesized that loss of tumor cells after Gamma Knife surgery (GKS) may alter the ADC value and used diffusion weighted MR imaging (DW imaging) to evaluate cellular changes in brain tumors to detect their treatment response and the efficacy of GKS.

Methods

In this paper the authors describe a prospective trial involving 86 patients harboring 38 solid or predominantly solid brain metastases, 30 meningiomas, and 24 acoustic neuromas that were treated by GKS. The patients underwent serial MR imaging examinations, including DW imaging, before treatment and at multiple intervals following GKS. Follow-up MR images and clinical outcomes were reviewed at 3-month intervals for metastatic lesions and at 6-month intervals for benign tumors. Apparent diffusion coefficients were calculated from echoplanar DW images, and mean ADC values were compared at each follow-up.

Results

The mean ADC value for all meningiomas was 0.82 ± 0.15 × 10−3 mm2/sec before GKS. The mean ADC value as of the last mean follow-up of 42 months was 1.36 ± 0.19 × 10−3 mm2/sec, a significant increase compared to that before treatment (p < 0.0001). Calcification (p = 0.006) and tumor recurrence (p = 0.025) significantly prevented a rise in the ADC level.

The mean ADC value for all solid acoustic neuromas was 1.06 ± 0.17 × 10−3 mm2/sec before GKS. The mean ADC value as of the last mean follow-up of 36 months was 1.72 ± 0.26 × 10−3 mm2/sec, a significant increase (p = 0.0002) compared with values before GKS. At the last mean MR imaging follow-up there appeared to be tumor enlargement in 3 patients (12.5%); however, since the ADC values in these patients were significantly higher than the preradiosurgery values, the finding was considered to be a sign of radiation necrosis rather than tumor recurrence.

The mean ADC value of metastatic tumors was 1.05 ± 0.12 × 10−3 mm2/sec before GKS. This value rose significantly (p < 0.0001) to 1.64 ± 0.18 × 10−3 mm2/sec after GKS at a mean follow-up of 9.4 months. Magnetic resonance imaging showed that 89% of these tumors had been controlled by GKS. In 2 patients there were enlarged lesions, but the ADC values were the same as pre-GKS levels, and therefore, the lesions were deemed recurrent.

Conclusions

Apparent diffusion coefficient values may be useful in evaluating treatment results before a definitive change in volume is evident on imaging studies. In some patients in whom imaging findings are equivocal, ADC values may also be used to distinguish radiation-induced necrosis from tumor recurrence.