Mobile intraoperative CT-assisted frameless stereotactic biopsies achieved single-millimeter trajectory accuracy for deep-seated brain lesions in a sample of 7 patients

BACKGROUND Brain biopsies are crucial diagnostic interventions, providing valuable information for treatment and prognosis, but largely depend on a high accuracy and precision. We hypothesized that through the combination of neuronavigation-based frameless stereotaxy and MRI-guided trajectory planning with intraoperative CT examination using a mobile unit, one can achieve a seamlessly integrated approach yielding optimal target accuracy. METHODS We analyzed a total of 7 stereotactic biopsy trajectories for a variety of deep-seated locations and different patient positions. After rigid head fixation, an intraoperative pre-procedural scan using a mobile CT unit was performed for automatic image fusion with the planning MRI images and a peri-procedural scan with the biopsy cannula in situ for verification of the definite target position. We then evaluated the radial trajectory error. RESULTS Intraoperative scanning, surgery, computerized merging of MRI and CT images as well as trajectory planning were feasible without difficulties and safe in all cases. We achieved a radial trajectory deviation of 0.97 ± 0.39 mm at a trajectory length of 60 ± 12.3 mm (mean ± standard deviation). Repositioning of the biopsy cannula due to inaccurate targeting was not required. CONCLUSION Intraoperative verification using a mobile CT unit in combination with frameless neuronavigation-guided stereotaxy and pre-operative MRI-based trajectory planning was feasible, safe and highly accurate. The setting enabled single-millimeter accuracy for deep-seated brain lesions and direct detection of intraoperative complications, did not depend on a dedicated operating room and was seamlessly integrated into common stereotactic procedures

Identifikacija biološki nerazgradivih zagađivača u riječnoj vodi

Over 100 non-biodegradable organic compounds, accumulated on a carbon filter of a Rhine waterworks, were isolated and identified by means of combined gas chromatography - mass spectrometry. The identified pollutants belong to five different classes: aliphatic as well as aromatic chlorinated hidrocarbons, nitro aromatic compounds, aromatic ethers, tert-butyl substituted phenols and phthalic acid esters. The potential toxicological hazard of the non-biodegradable organic compounds is briefly discussed.Biološki nerazgradivi organski spojevi djeluju nepovoljno na kvalitetu riječne vode koja služi za ljudsku upotrebu i prouzrokuju sekundarne efekte utječući na ekologiju rijeke. Ti se biološki nerazgradivi organski spojevi nakupljaju na ugljenim filtrima vodovoda. Za identifikaciju biološki nerazgradivih organskih spojeva, uzorak ugljenog filtra njemačkog vodovoda s donjeg toka rijeke Rajne, ekstrahiran je s organskim otapalima. Ekstrakti su separirani kromatografskim tehnikama te identificirani pomoću spektrometra masa vezanog uz plinski kromatograf. Neovisno o tome spojevi su identificirani mjerenjem vremena zadržavanja te pomoću infracrvene spektroskopije nakon hvatanja uzorka s maksimuma. Identificirane je više od 100 organskih spojeva. Većina pripada klasama kloriranih alifatskih i aromatskih ugljikovodika, aromatskih nitrospojeva i terc-butil supstituiranih aromatskih ugljikovodika