Intraoperative low-field magnetic resonance imaging in pediatric neurosurgery

Since the mid-1990s, the feasibility and indications of intraoperative magnetic resonance (MR) imaging have been investigated by different groups. The majority of examinations were carried out in adults. The aim of this study was to summarize our experience of over 5 years of intraoperative MR imaging in pediatric neurosurgery.

For scanning, we used a 0.2-Tesla Magnetom Open, which was placed in a radiofrequency-shielded twin operating theater, allowing surgery with standard instruments and additional neuronavigational guidance either in an adjacent operating room or directly in the radiofrequency cabin on the extended MR table, at the 5-G line.

In total, 330 patients were investigated, among them 33 children who were younger than 17 years. We found four main indications for intraoperative MR imaging: the evaluation of cyst drainage (n = 9), of the extent of resection in epilepsy surgery (n = 6) and of the removal of pituitary tumors (n = 6) and gliomas and other brain tumors (n = 12). Intraoperative MR imaging allowed us to evaluate the extent of the resection or to monitor catheter placements and consecutive cyst alterations in all cases. In 2 tumor cases and 3 catheter placements, intraoperative imaging resulted in a modification of the surgical strategy.

Intraoperative low-field MR imaging is a safe procedure; we did not encounter an increased morbidity in the children investigated. It serves as intraoperative quality control documenting the effects of surgery, e.g. the extent of a resection, which can then be compared to the treatment plan. Besides its most essential application in brain tumors, it also proved to be particularly helpful in children undergoing complicated catheter placements for cyst drainage, as well as in pituitary and epilepsy surgery.