**2.5. Radiographic appearance**

The typical appearance of high grade glioma is an irregular and heterogeneously enhancing lesion on T1-weighted images. After treatment, there are typical changes that are observed on subsequent imaging studies [40–42]. Immediately after procedure one can appreciate an area of hyperintensity within the lesion on T1-weighted MRI images. This finding corresponds to coagulated blood products within the ablated area. On the corresponding CT scans this would appear as a hyperdense area typical in appearance of blood products. With administration of contrast, there is typically an area of peripheral rim enhancement. This is thought to represent an area of sublethal tissue damage with disrupted blood-brain barrier and leaky capillaries [7].

and median overall survival in the study was >30%. One patient had a new permanent postoperative neurological deficit, and one patient had a vascular injury resulting in a pseudoaneurysm. Both patients were in the white TDT line subgroup. This study demonstrated that LITT is a feasible and safe treatment modality for recurrent high-grade gliomas, and that the

Laser Interstitial Thermal Therapy in Glioblastoma http://dx.doi.org/10.5772/intechopen.77078 193

The first multicenter study to investigate whether cytoreduction achieved with the use of laser for difficult to access high-grade gliomas could have a similar survival benefit compared to surgery was a retrospective study that looked at outcomes in 34 patients with high grade gliomas that were treated with LITT, 19 of them treated upfront, and 16 patients as salvage therapy [48]. The median overall survival was not reached in the study. One year estimated overall survival was 68%, and median progression free survival was 5.1 months. They also demonstrated that increased coverage by the thermal damage threshold lines correlated with better progression free survival of 9.7 vs. 4.6 months. The latter also relates to tumor volume with smaller tumors being easier to achieve complete coverage with TDT lines. When looking at failure patterns, 5 tumors recurred within the treatment field, 12 patients recurred at the periphery of the treated volume, 5 tumors recurred within 2 cm of the original area of enhancement, and one case had a remote recurrence. Overall, the authors concluded that LITT is an effective treatment modality for newly diagnosed and recurrent high-grade gliomas with improved outcomes correlating with extent of tumor coverage by analogy with

Recently, a meta-analysis of the efficacy of LITT treatment of newly diagnosed and recurrent high-grade gliomas was published [49]. Ivan et al. extracted information and analyzed the data pertaining to treatment and outcomes of newly diagnosed high-grade gliomas treated with LITT. They identified four articles that reported treatment of 25 patients with newly identified

extent of volume treated with laser was available for 9 patients with an average of 82.9% tumor coverage. Complications data was available for 13 patients, and there were no intraoperative mortality or complications. Serious postoperative complications occurred in two patients, one succumbing to postoperative central nervous system infection, and another one requiring hemicraniectomy for malignant post treatment cerebral edema. No permanent new postoperative neurological complications were noticed among these patients. Outcome analysis revealed a mean follow up of 7.6 months, with 12 patients still followed or lost to follow-up. Median overall survival was 14.2 months and the average PFS was 5.1 months. These results are similar to results reported in the literature that vary from 8.5 to 14.5 months [50, 51]. Thus, this systematic review demonstrates that LITT is a safe and effective procedure for newly diagnosed

, whereas the

gliomas. Tumor volume was available for 22 patients and the mean was 16.5 cm3

high-grade gliomas achieving outcomes similar to cases with open surgical resection.

Even with the full complement of modern treatments, the survival of glioblastoma patients remains poor in the range of 14–16 months after surgery, chemotherapy and radiation. Recurrence is the rule rather than the exception, at which point the prognosis is quite poor with the 6-month progression free survival rates of 5–15% [52, 53]. Reoperation in the recurrent setting was shown to be of benefit [54]. The risk of complications needs to be weighed against potential survival benefit, which is where the role for the use of LITT in recurrent

blue line should be used as the margin of treated area.

extent of resection in surgical series.
