Assessment of the treatment response of spinal meningiomas after radiosurgery focusing on serial MRI findings

Purpose This study evaluated the response of spinal meningiomas to treatment, by monitoring changes in magnetic resonance imaging (MRI) findings after stereotactic radiosurgery (SRS). Materials and methods Serial follow-up MRIs of 11 patients with spinal meningiomas who underwent SRS were retrospectively reviewed. Changes in tumor volume, T2 signal intensity (T2SI), and contrast enhancement were evaluated. Results The mean MRI follow-up period was 46.9 months (range 13–108 months). The local tumor control rate was 100 % in overall tumor volume, although boost SRS was performed for marginal recurrence in case 8 and rapid decompression in case 5. Seven tumors showed decreased T2SI. Each of the remaining four tumors showed variable T2SIs. In most tumors, the enhancement patterns did not change. Two of three patients with en plaque type meningiomas showed increased intramedullary T2SI, thought to be due to compressive myelopathy and peritumoral edema. Conclusions SRS resulted in successful local tumor control in all patients, although the follow-up period was not long. Changes in T2SI and contrast enhancement patterns of the tumors were evaluated on serial MRI. In addition, close follow-up with MRI is desirable to monitor intramedullary signal changes in cases of spinal meningiomas with a wider contact area with the spinal cord.