Study Identifies New Way to Biopsy Brain Tumours in Real Time

Phoenix, AZ - A new miniature, hand-held microscope may allow more precise removal of brain tumours and an easier recognition of tumour locations during surgery, according to a report from St. Joseph's Hospital and Medical Center, Phoenix, Arizona.

Neurosurgeons at Barrow Neurological Institute at St. Joseph's Hospital and Medical Center are using the new miniature laser confocal microscope to view brain tumour regions during surgery and obtain digital images of the tumour and brain tissue. This was not previously possible without taking biopsies of the tissue.

The microscope is used to image the tissue after a fluorescent drug is injected into the patient and travels into the tumour. The first application of the technology in the research lab at Barrow showed that it was possible to distinguish cancer cells and the margin of the brain tumour without taking a biopsy. Barrow researchers also discovered that it was possible to obtain a digital video of the brain tumour to show blood flowing through the abnormal vessels of the tumour and the transition from normal to abnormal brain tissue.

Typically, intraoperative diagnosis is performed by obtaining several specimens from within a brain tumour using biopsy forceps and cutting, freezing and staining the specimen for examination under the microscope. The traditional analysis is limited by sampling error and by mechanical tissue damage from the biopsy forceps, slowing operative workflow by 30 to 40 minutes.

The new microscope can overcome these limitations by helping to visualize the cellular and tissue features of a tumor in real-time. As in the study, the probe can be moved over the entire visible extent of a tumour, guiding the neurosurgeon to hypercellular or aggressive areas that are likely to generate high-yield biopsies.

"As neuropathologists become familiar with the new confocal microscopic appearance of various tumour types and grades, the traditional intraoperative diagnosis may be replaced by the real-time analysis of confocal images by the new microscope," says Dr. Mark Preul, Newsome Chair of Neurosurgery Research at Barrow. These images could be analyzed remotely, improving the accuracy of intraoperative diagnosis.