Multimodal MRI to Differentiate Subtypes of Intramedullary Spinal Cord Tumours: A Pilot Study

Intramedullary spinal cord tumours (IMSCTs) are a type of tumour that arises from cells within the spinal cord. They are rare, accounting for around 4-10% of central nervous system tumours. They commonly present as back/neck pain and have poor outcomes if not treated.

IMSCTs fall into various subtypes. Around 90% are either ependymomas or astrocytomas. Ependymomas are usually quite distinct from the surrounding tissue and therefore can often be treated successfully with surgery. In contrast, astrocytomas tend to invade the surrounding tissue and, as a result, generally cannot be entirely surgically removed. Radiotherapy is recommended instead of surgery for tumours that cannot be operated. Unfortunately, ependymomas and astrocytomas can appear very similar on diagnostic scans and are therefore difficult to tell apart before surgery. Biopsy therefore remains the current gold standard for tumour subtype differentiation.

Any spinal cord surgery, whether it be biopsy or resection, poses major challenges due to the small size of the spinal cord. A small corridor via the back of the spinal cord, known as the posterior midline, usually offers the safest approach to a tumour. However, finding this access corridor can be very difficult because tumours tend to deform the anatomy of the spinal cord, leading to a high risk of injury to the normal spinal cord tissue or nerves.

The primary objective of this pilot study is to test if cutting-edge spinal cord magnetic resonance imaging (MRI) techniques could help to better differentiate between tumour subtypes. The investigators will do this by comparing various imaging metrics between the tumour subtypes, confirmed by biopsy. The investigators' second objective is to see if these MRI techniques could help to identify, pre-surgery, the location of the posterior midline of the spinal cord. The investigators will do this by comparing the prediction of the midline location from imaging with blinded observations by the surgeon during planned surgery. Additionally, the investigators want to investigate the relationship between imaging metrics and patient pain and sensorimotor symptoms, to explore if imaging offers insight into the variety of clinical symptoms associated with these tumours.

The investigators' hope is that the results of this study could inform a future larger trial that would be designed to fully assess the utility of cutting-edge MRI techniques for reducing both the need for spinal cord surgery and the risks associated with surgery in IMSCT patients.