Tag: Spectroscopy

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One-Insertion Stereotactic Brain Biopsy Using In Vivo Optical Guidance

Operative Neurosurgery 25:176–182, 2023

Stereotactic neurosurgical brain biopsies are afflicted with risks of inconclusive results and hemorrhage. Such complications can necessitate repeated trajectories and prolong surgical time.

OBJECTIVE: To develop and introduce a 1-insertion stereotactic biopsy kit with direct intraoperative optical feedback and to evaluate its applicability in 3 clinical cases.

METHODS: An in-house forward-looking probe with optical fibers was designed to fit the outer cannula of a side-cutting biopsy kit. A small aperture was made at the tip of the outer cannula and the edges aligned with the optical probe inside. Stereotactic biopsies were performed using the Leksell Stereotactic System. Optical signals were measured in millimeter steps along the preplanned trajectory during the insertion. At the region with the highest 5-aminolevulinic acid (5-ALA)induced fluorescence, the probe was replaced by the inner cannula, and tissue samples were taken. The waiting time for pathology diagnosis was noted.

RESULTS: Measurements took 5 to 10 minutes, and the surgeon received direct visual feedback of intraoperative 5-ALA fluorescence, microcirculation, and tissue gray-whiteness. The 5-ALA fluorescence corroborated with the pathological findings which had waiting times of 45, 50, and 75 minutes. Because only 1 trajectory was required and the patient could be prepared for the end of surgery immediately after sampling, this shortened the total surgical time. CONCLUSION: A 1-insertion stereotactic biopsy procedure with real-time optical guidance has been presented and successfully evaluated in 3 clinical cases. The method can be modified for frameless navigation and thus has great potential to improve safety and diagnostic yield for both frameless and frame-based neurosurgical biopsy procedures.

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Advanced MRI may complement histological diagnosis of lower grade gliomas and help in predicting survival

Advanced MRI may complement histological diagnosis of lower grade gliomas and help in predicting survival

J Neurooncol (2016) 126:279–288

MRI grading of grade II and III gliomas may have an important impact on treatment decisions. Occasionally, both conventional MRI (cMRI) and histology fail to clearly establish the tumour grade. Three cMRI features (no necrosis; no relevant oedema; absent or faint contrast enhancement) previously validated in 196 patients with supratentorial gliomas directed our selection of 68 suspected low-grade gliomas (LGG) that were also investigated by advanced MRI (aMRI), including perfusion weighted imaging (PWI), diffusion weighted imaging (DWI) and spectroscopy. All the gliomas had histopathological diagnoses.

Sensitivity and specificity of cMRI preoperative diagnosis were 78.5 and 38.5 %, respectively, and 85.7 and 53.8 % when aMRI was included, respectively. ROC analysis showed that cut-off values of 1.29 for maximum rCBV, 1.69 for minimum rADC, 2.1 for rCho/Cr ratio could differentiate between LGG and HGG with a sensitivity of 61.5, 53.8, and 53.8 % and a specificity of 54.7, 43 and 64.3 %, respectively. A significantly longer OS was observed in patients with a maximum rCBV\1.46 and minimum rADC[1.69 (80 vs 55 months, p = 0.01; 80 vs 51 months, p = 0.002, respectively). This result was also confirmed when cases were stratified according to pathology (LGG vs HGG). The ability of aMRI to differentiate between LGG and HGG and to predict survival improved as the number of aMRI techniques considered increased.

In a selected population of suspected LGG, classification by cMRI underestimated the actual fraction of HGG. aMRI slightly increased the diagnostic accuracy compared to histopathology. However, DWI and PWI were prognostic markers independent of histological grade.

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