4418 - Role of Intraoperative MRI (iMRI) in neurosurgery, potential imaging tool for maximizing gross total resection (GTR) rate of CNS tumours.

Background

High field iMRI with integrated neuronavigation system is an advanced diagnostic tool gives information about extent of resection allowing immediate update of neuronavigation parameters after anatomic changes occuring as a result of tumour resection, cerebrospinal fluid evacuation and brain shift.

Methods

20 CNS tumour cases underwent Brain suite MRI prior to surgery, then surgery was done after patient registration in navigation system using iMRI. Preoperative tumor volume was manually segmented, compared with intraoperative volume after first resection attempt and final post operative volume after surgical closure to calculate extent of resection (EOR).Descriptive statistics were used to find mean, SD, frequency, percentage of variables. Normally distributed interval data reported as means by two-sample t- test. Non-normally distributed interval/ordinal data reported as median{inter-quartile ranges} and compared among groups by Wilcoxon exact test to obtain EOR values.

Results

20 cases allocated to two groups (G), 1st in whom surgery was complete after first iMRI and 2nd who underwent further tumour removal. In G1 surgery was terminated in 11 cases after iMRI, GTR in 81.8% cases. iMRI showed subtotal resection(STR) in 18.2% patients but surgery stopped owing to infiltration of eloquent brain. Median preoperative tumour volume was 40.8cm3. Median postoperative tumour volume was 0.81cm3 with a significant p value (<0.001). Median EOR was 98.5% in G1. In G2, 9 of 20 (45%) underwent further resection of residual tumour after post resection iMRI. GTR in 77.7% and STR in 22.3%, because of tumour’s close proximity to eloquent brain area. Median % of tumour resection after the first iMRI was 82.65%. Median EOR from the final postoperative iMRI was 98.3%. GTR increased from 45% to 80 % after use of iMRI. Median % of residual tumour volume significantly decreased from 5.3% to 1.7 % (p value <0.001). Mean control tumour volume was 9.67% and final post operative volume of 4.72% , which is almost half of intraoperative tumour volume (p value <0.001).

Conclusions

iMRI has potential role in maximizing gross total resection rates of CNS tumours which has an overall great prognostic impact.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Institutional ethics committee, Max Superspeciality Hospital, New Delhi.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.