Real-time ultrasound-MRI fusion image virtual navigation for locating intraspinal tumour in a pregnant woman.

Background: Standard fluoroscopic guidance (C-arm fluoroscopy) has been routinely used for intraoperative localization of spinal level for surgical removal of intraspinal tumour, while it is not suitable for selected patients, e.g. pregnant women, who need to avoid radiation exposure. Fusion imaging of real-time ultrasound (US) and magnetic resonance imaging (MRI) is a radiation-free technique which has been reported to have good localization accuracy in managing several conditions.
Clinical Presentation: A 37-year-old pregnant patient, presented with a progressively aggravating lower back pain for 20 days and was incapable of lying supine with lower extremities swelling for 1 week, was referred to our hospital in her 18th week of gestation. Lumbar MRI identified an L1 level intraspinal lesion, and surgery was planned. To avoid the ionizing radiation generated by fluoroscopy, volume navigation technique (VNT) based fusion imaging of US and MRI was used to localize the intraspinal lesion, which was removed entirely via minimally invasive interlaminar approach. Pathological examination confirmed the diagnosis of ependymoma of the conus medullaris. Her symptoms were largely relieved after the operation, and a healthy baby was delivered at the 40th week of pregnancy.
Conclusion: We presented the first case of using VNT based fusion imaging of real-time US/MRI to guide the surgical resection of an intraspinal tumour. Future study with larger patient number is needed to validate this technique as an alternative to fluoroscopy in patients who need to avoid radiation exposure.