Laser biospectroscopy and 5-ALA fluorescence navigation as a helpful tool in the meningioma resection.

5-aminolevulinic acid (5-ALA) is a natural precursor of protoporphyrin IX (PP IX), which possesses fluorescent properties and is more intensively accumulated in tumor cells than in normal tissue. Therefore, the use of 5-ALA in the surgical treatment of intracranial tumors, particularly gliomas, has gained popularity in the last years, whereas its use in other intracranial pathological entities including meningiomas has been reported occasionally. This study describes a series of 28 patients with intracranial meningiomas, who were administered 5-ALA for a better visualization of tumor boundaries. Twelve patients underwent also laser spectroscopic analysis in order to confirm the visual impression of tumor tissue visualization. Bone infiltration was readily demonstrated. In one case, the tumor recurrence could have been prevented by removal of a tumor remnant, which would possibly have been better recognized if spectroscopic analysis had been used. Fluorescent navigation (FN) is a useful method for maximizing the radicality of meningioma surgery, particularly if the tumor infiltrates the bone, the skull base, and/or the surrounding structures.

[Clinical guidelines for the use of intraoperative fluorescence diagnosis in brain tumor surgery].

In this paper, we present a review of current literature on the application of intraoperative fluorescence diagnosis and fluorescence spectroscopy using 5-aminolevulinic acid in surgery for various types of brain tumors, both alone and in combination with other neuroimaging methods. Authors' extensive experience with these methods allowed them to develop a set of clinical guidelines for the use of intraoperative fluorescence diagnosis and fluorescence spectroscopy in surgery of brain tumors.

[The structure of activation of the language zone in patients with intracerebral tumors according to fMRI with respect to tumor location and the functional asymmetry profile].

MATERIAL AND METHODS: A total of 50 patients were examined prior to surgical resection of intracranial tumors of the temporal and frontal lobes. Left-sided tumors were observed in 33 patients and right-sided tumors were observed in 17 patients. The functional asymmetry profile was determined using self-assessment, the Annet questionnaire, and the dichotic listening task. Twelve patients were left-handers or retrained left-handers and the remaining 38 patients were right-handers. FMRI examination was carried out on a 3.0 T SignaHDxt magnetic resonance tomograph (GE). The standard language block design paradigm was used in the study. We used the following tests: 1) recitation of months in reverse order; 2) generation of nouns according to the initial letters shown on the screen (K, M, L, N, P, C); 3) generation of verbs according to simple actions shown on the screen; 4) producing sentences using nouns shown on the screen; 5) listening to text through headphones. Data were processed using the standard BrainWave PA software (General Electric). Z-test was used in the range from 6 to 9. In all the studies, p<0.001. Statistical data processing included the nonparametric Spearman's test to determine the correlation between lateralization of the detected activation zone under speech load and tumor location (tumor is adjacent to the language zone, invades the language zone, or is located far from the language zone), as well as left- or right-handedness. RESULTS: Among 16 patients (right-handers and 2 left-handers) the activation of language zones was observed only on the left side; in one left-handed patient, Broca's area was detected only on the right side. In other patients (including right-handers with right-sided tumors), lateralization of language zones was different, including bilateral. Statistical processing revealed that bilateral activation of both Broca's and Wernicke's areas was more frequently observed in left-handers. Broca's area was more frequently detected on the left side in the presence of a distant tumor, while this trend did not apply for Wernicke's area. CONCLUSION: Localization of activation of Broca's area is more dependent on tumor location, while it depends on personal characteristics of an individual in the case of Wernicke's area.

[Intraoperative fluorescence diagnostics upon recurrent operations for brain gliomas].

UNLABELLED: The method of fluorescent diagnosis (FD) using 5-ALA has been widely employed in surgery of primary intracerebral tumors over the last years. The issue of FD application in surgery of gliomas with continued growth has remained less studied. OBJECTIVE: To investigate the efficacy of using FD with 5-ALA and laser spectral analysis in surgery of brain gliomas with continued growth. MATERIAL AND METHODS: 19 patients with Grade II-IV (WHO) gliomas with continued growth of different localization were studied. All tumors localized supratentorially. 5-Aminolevulinic acid hydrochloride "Alasens" (SSC "NIOPIK", Moscow, Russia) was used in the study. The equipment used during surgery included an operating microscope with an attachment for fluorescent navigation. Apart from expert qualitative assessment of a fluorescence extent, computer analysis of the fluorescence and light scattering (diffuse reflection) spectra was performed on a LESA-01-BIOSPEK spectrum analyzer (Russia). RESULTS: Detectable fluorescence was obtained in all the cases. PP IX fluorescence indices from 9.05 to 53.97 (the study was conducted in 12 cases) were determined by quantitative analysis of the spectrograms. The analysis of light scattering revealed its inverse relationship with respect to the fluorescence index. High sensitivity of the method in surgery of gliomas with continued growth requires clarification of method specificity because non-specific accumulation of PP IX in the area of post-radiation necrosis may occur in these patients. CONCLUSIONS: The FD method can be used for intraoperative demarcation of tumor resection boundaries in surgery of cerebral gliomas with continued growth. However, it is necessary to be critical of the high sensitivity of the method in patients with postradiation pathomorphism due to possible non-specific accumulation of PP IX in tissues. A light scattering study may provide additional information about the structure of tissues in the surgical wound.

[Intraoperative combined spectroscopy (optical biopsy) of cerebral gliomas]. / Intraoperatsionnaia kombinirovannaia spektroskopiia (opti-cheskaia biopsiia) gliom golovnogo mozga.

Clinical studies have revealed high selectivity of 5-ALA-induced protoporphyrin IX accumulation in different brain tumors. Modern methods of evaluation of tissues visible fluorescence are based on the qualitative analysis of the images. Up-to-date methods of combined spectral analysis allow fulfilling the intraoperative quantitative evaluation of the protoporphyrin IX content, as well as the scattering and absorption properties of a tissue. This paper presents a new method of the simultaneous analysis of hemoglobin concentration in oxygenated and reduced forms, tumor marker concentration (5-ALA-induced PP IX) and a new way to analyze the changes in the scattering properties of the tissues. The method is implemented by splitting the visible spectrum into intervals where hemoglobin and protoporphyrin IX have the characteristic peaks of absorption and fluorescence. The present method shows the dependence of the fluorescence index from the tumor grade. Combined spectroscopy (optical biopsy) can detect the differences between the subtypes of gliomas that are similar in the protoporphyrin IX fluorescence index. This method complements and enhances the diagnostic capabilities of spectroscopy, which is particularly important in the non-fluorescent glioma surgery.