gms | German Medical Science

Objective: Early detection and evaluation of brain tumors during surgery is crucial for accurate resection. Currently cryosections during surgery are regularly performed. Confocal laser endomicroscopy (CLE) is a novel technique permitting in vivo histologic imaging with miniaturized endoscopic probes at excellent resolution. The aim of the current study was to evaluate CLE for in vivo diagnosis in different types and models of intracranial neoplasia.

Method: In vivo histomorphology of healthy brains and two different C6 glioma cell line allografts were evaluated in rats. One cell line expressed EYFP, the other cell line was used for staining with fluorescent dyes (fluorescein, acriflavine, FITC-dextran and Indocyanine green). To evaluate future application in patients, fresh surgical resection specimen of human intracranial tumors (n=15) were examined (glioblastoma multiforme, meningioma, craniopharyngioma, acoustic neurinoma, brain metastasis, medulloblastoma, epidermoid tumor). Healthy brain tissue adjacent to the samples served as control.

Results: CLE yielded high-quality histomorphological differentiation between normal brain tissue and tumors. Different fluorescent agents revealed distinct aspects of tissue and cell structure (nuclear pattern, axonal pathways, hemorrhages). CLE discrimination of neoplastic from healthy brain tissue was easy to perform based on tissue and cellular architecture and resemblance to histopathology was excellent.

Conclusions: Confocal laser endomicroscopy allows immediate in vivo imaging of normal and neoplastic brain tissue at high resolution. The technology may be transferred to scientific and clinical application in neurosurgery and neuropathology. It may become helpful for screening for tumor-free margins and to improve the surgical resection of malignant brain tumors, as well as opening the door to in vivo molecular imaging of tumors and other neurologic disorders.