BACKGROUND:5-Aminolevulinic acid is used for fluorescence-guided resections. During resection, different macroscopic fluorescence qualities (“strong,” “weak”) can be distinguished that help guide resections.OBJECTIVE:This prospective study was designed to assess the reliability of visible fluorescence qualities by spectrometry, pathology, and imaging.METHODS:Thirty-three patients with malignant gliomas received 5-aminolevulinic acid (20 mg/kg). After debulking surgery, standardized biopsies were obtained from tissues with “weak” and “strong” fluorescence and from nonfluorescing near and distant brain for blinded assessment of cell density and tissue type (necrosis, solid or infiltrating tumor, normal tissue). The positive predictive value was calculated. Unresected fluorescing tissue was navigated for blinded correlation to postoperative magnetic resonance imaging (MRI). Receiver operating characteristic curves were generated for assessing the classification efficiency of spectrometry.RESULTS:“Strong” fluorescence corresponded to greater spectrometric fluorescence, solidly proliferating tumor, and high cell densities, whereas “weak” fluorescence corresponded to lower spectrometric fluorescence, infiltrating tumor, and medium cell densities. The positive predictive value was 100% in strongly fluorescing tissue and 95% in weakly fluorescing tissue. Spectrometric fluorescence was detected in marginal tissue without macroscopic fluorescence. Depending on the threshold, spectrometry displayed greater sensitivity but lower specificity (accuracy 88.4%). Residual MRI enhancement in the tumor bed was detected in 15 of 23 (65%) patients with residual fluorescence, but in none of the patients without residual fluorescence.CONCLUSION:Macroscopic fluorescence qualities predict solid and infiltrating tumor, providing useful information during resection. Fluorescence appears superior to contrast enhancement on MRI for indicating residual tumor. Spectrometry, on the other hand, is more sensitive but less specific, depending on threshold definition.ABBREVIATIONS:5-ALA, 5-aminolevulinic acidCI, confidence intervalgamma-GT, gamma-glutamyl transpeptidaseGBM, glioblastoma multiformeNPV, negative predictive valuePPIX, protoporphyrin IXPPV, positive predictive valueSD, standard deviationWHO, World Health Organization

The use of FL for the resection of brain tumors is safe and feasible. Presumably, the visualization of the tumor margin depends on the histopathology and on the pre-treatment status. A randomized evaluation of FL under the YELLOW 560 nm filter is planned to prospectively analyze the extent of resection in patients with malignant brain tumors.

No abstract

CBF-studies using the Xenon-133-inhalation technique were performed in 18 patients with a unilateral carotid artery occlusion, 5.4 years after a STA-MCA procedure. For comparison we used the CBF data of 29 patients with the same diseases who had had conservative treatment for a variable period of time. CBF was measured during rest and after the intravenous administration of 1 g acetazolamide. During rest we found a significant interhemispheric difference in both groups. After activation with acetazolamide this difference disappeared in the bypass group, but not in the conservatively treated patients. Our data show that the bypass procedure obviously affects the vascular reserve capacity in a positive way over a long period of time. One criteria for success of STA-MCA procedures might be the cerebral reserve capacity tested with CBF-studies under activation.

Fenestrations and duplications of the cervical and intracranial arteries are rare anatomic variants, reported to be associated with aneurysms or other vascular anomalies. We here present a patient with a supraclinoid ICA fenestration in combination with a duplication of the MCA originating from the ICA fenestration and an associated aneurysm.