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Objective: In diffusely infiltrating gliomas (DIG), positron emission tomography (PET) imaging is a powerful method for detection of anaplastic foci. Recently, (1)H-magnetic resonance spectroscopy chemical shift imaging (CSI) using choline/creatine (Cho/Cr) or choline/N-acetylaspartate (Cho/NAA) ratios has emerged as a new non-invasive, widely available alternative. The authors therefore correlated CSI with (11)C-methionine (MET)-PET data in a series of DIG with non-significant contrast-enhancement (CE).Methods: Thirty-two patients with DIG were examined with single-slice CSI on a T MRI and MET-PET. Maximum pathological intratumoural ratios of CSI (=CSI(max)) and maximum tumour-to-normal-brain PET ratios (=PET(max); T/N ratio) were determined. Coregistration of MRI with CSI and PET was performed, and the topographic overlap of CSI(max) and PET(max) was analysed. Histological criteria of anaplasia as well as cell proliferation rate were assessed in tumour samples inside and outside CSI(max).Results: CSI showed a pathological ratio in all patients, whereas PET demonstrated a pathological T/N ratio in 21/32 patients. Topographical correlation of CSI(max) and PET(max) revealed a ≥ 50% overlap in 18/21 and <50% overlap in 3/21 patients, respectively. Cho/Cr(max) and Cho/NAA(max) showed a ≥ 50% overlap in 24/32 and a <50% overlap in 8/32 patients. Cell proliferation rate was significantly higher inside than outside the CSI(max) (13.6% vs 6.9%, p<0.001).Conclusion: The results indicate that CSI is a promising method for detection of anaplastic foci within DIG with non-significant CE. Intraoperative use of CSI by multimodal neuronavigation may increase the reliability of detection of malignant areas in glioma surgery and therefore optimise allocation of patients to adjuvant treatments. [ABSTRACT FROM AUTHOR]

Background: Currently, no effective alternative treatment exists for progressive, regrowing, nonfunctioning pituitary adenomas (NFPA) that are resistant to conventional multimodality therapy. Temozolomide (TMZ) was proposed as a treatment option for pituitary carcinomas and aggressive pituitary adenomas. Recently, it was suggested that the responsiveness of pituitary tumors to TMZ depends on the immunoexpression of O(6)-methylguanine DNA methyltransferase (MGMT). Therefore, the authors of this report assessed MGMT expression in a series of patients with progressive, regrowing NFPAs to evaluate whether TMZ may serve as alternative treatment option.Methods: On the basis of postoperative magnetic resonance imaging, 45 patients with NFPAs were allocated to either a group with progressive, regrowing tumors (n = 24) or a tumor-free group (n = 21), which served as a control. MGMT expression was assessed semiquantitatively by immunohistochemistry (low expression was defined as 50% immunostained adenoma cells) and was compared between the 2 groups.Results: At the time of initial surgery, low MGMT expression was observed in 12 of 24 patients (50%) in the study group with progressive, regrowing NFPAs. In the control group of tumor-free patients, only 5 of 21 patients (24%) exhibited low MGMT expression. A comparable distribution of MGMT expression was observed in the specimens from repeat surgeries. A shorter interval to second surgery was observed in patients who had low MGMT expression.Conclusions: The current data has suggested that half of the patients with progressive, regrowing NFPAs exhibit low MGMT expression and are potential candidates for treatment with TMZ. These findings provide a rationale for the use of TMZ as an alternative treatment approach in this subgroup if conventional therapy, including reoperation, radiosurgery, and radiotherapy, fails. [ABSTRACT FROM AUTHOR]

Objective: Volume segmentation with concurrent visualization is becoming an increasingly important part of medical diagnostics. This is due to the fact that the immediate visual feedback speeds up evaluation of the segmentation process, hence enhances segmentation quality. Therefore, our aim was to develop a method for volume segmentation and smoothing which achieves interactive performance on standard PCs and is useful in clinical practice (i.e. fast and of high quality).Methods: Our application is based on seeded region growing and nonlinear isotropic as well as anisotropic diffusion. We use current GPUs (graphics processing units) to speed up the computation of the diffusion process and use hardware-accelerated interactive volume rendering.Results: Using our approach the user can observe the diffusion process in real-time, change parameters interactively and view the result in a high-quality 3D direct volume rendering (DVR).Conclusion: The interactive nature of our algorithm and simultaneous visualization improved the usability of our segmentation and smoothing algorithm and proved useful in the clinical workflow. Using our application we were able to speed up the (an)isotropic diffusion process to achieve interactive performance. [ABSTRACT FROM AUTHOR]