DIFFERENTIAL DIAGNOSTICS OF A RADIONECROSIS AND LOCAL TUMORAL RECURRENCE ACCORDING TO ARTERIAL SPIN LABELLING AFTER RADIOSURGERY TREATMENT OF MALIGNANT GLIOMAS OF A BRAIN

Abstract

The aim: Assessment of a possibility of performing differential diagnostics of the post-beam radio necrosis (PBRN) and the local recurrence (LR) after the carried-out stereotaxic radio surgery (SRS) according to perfusion on the basis of non-contrast pulse arterial backs markings (PASL). Materials and methods: In our research, we consider results of the stereotactic radiosurgery (SRS) which is carried out to 20 patients with the diagnosis the malignant glioma of a brain (MGB) in respect differential diagnostics of a local tumor recurrence and radionecrosis according to perfusion non-contrast MRT of a research on the basis of the sequence of PASL. The diagnosis of MGB before carrying out SRS was established to all 20 patients on the basis of a histologic research on data of a biopsy. From them the anaplastic astrocytoma (AnASTs, grade III) and at 14 - a glioblastoma was diagnosed for 6 patients (GBM, grade IV). Confirmations of the post-beam diagnosis it was carried out on the basis of a histologic research on results of a stereotactic biopsy or a surgical resection. Traditional methods of medical statistics were applied to processing of the statistical information obtained in a research at all its stages (calculation of average and relative sizes with their errors), also graphic and tabular methods were applied to rational evident statement of the received results. Results: The diagnosis of a local tumor recurrence according to a relative regional blood-groove on the basis of PASL was exposed to 8 patients and confirmed histologically (to 5 patients underwent surgical resection, 3 - according to biopsy data). Patients with a confirmed diagnosis of relapse according to biopsy were performed in 1 case, repeated radiosurgery and in 2 cases (with a diagnosis of multifocal continued growth of glioblastoma) - irradiation of the entire brain. Radionecrosis was diagnosed in 12 cases. In 6 cases, it was confirmed on the basis of clinical diagnostic data of dynamic observation of patients, in 3 cases - according to surgical resection, and in 3 cases - according to stereotactic biopsy. According to our data, the average rrCBF based on arterial spin labelling (PASL) rTPmean ≤ 0.8ml / 100g / minute most likely testified in favor of radionecrosis, average ≥ 1.5ml / 100g / min - in favor of tumor progression, the maximum rTPmax ≤ 1.3ml / 100g / min most likely testified in favor of radio-necrosis, the maximum indicator rTPmax≥ 1.8ml / 100g / min - in favor of tumor progression. Conclusions: According to a relative regional blood flow of rrCBF based on non-contrast PASL perfusion, it is possible to reliably carry out a differential diagnosis of radionecrosis and local tumor recurrence in patients undergoing radiosurgical treatment for malignant gliomas of the brain.