Comparison of 1D and 3D volume measurement techniques in NF2-associated vestibular schwannoma monitoring

Abstract

Abstract To compare 1D (linear) tumor volume calculations and classification systems with 3D-segmented volumetric analysis (SVA), focusing specifically on their effectiveness in the evaluation and management of NF2-associated vestibular schwannomas (VS). VS were clinically followed every 6 months with cranial, thin-sliced ( 0.5) correlated with SVA (p < 0.001). The OA showed an even stronger positive correlation than the MLD3 to SVA. Smaller classified tumors (T1/T2, K1/K2) exhibited a low-moderate positive correlation (r2 = 0.23–0.44) compared to medium-sized (T3, K2/3) and large tumors (T4, K4; r2 = 0.54–0.76). Pre- and postoperative MLD3 and OA statistically significantly predict SVA (p < 0.001), but the postoperative correlation was weaker, particularly for MLD3 to SVA values. All analyses showed a large scatter range. In the percentage deviation analysis of MLD3 and OA from SVA, small tumors (K1/K2, T1/T2) were overestimated. Compared to the SVA, the MLD3 and especially the OA are a time-saving alternative for monitoring the tumor volume of NF2-associated VS. However, the scatter range in small/surgically reduced tumors is enormous. For this reason, they are not recommended for monitoring off-label therapy with Bevacizumab or for treatment decisions depending on a precise assessment of tumor volume and growth. Developing deep learning-based volume determinations in the future is essential to reduce SVA’s time intensity.

Keywords

• Vestibular Schwannoma
• Neurofibromatosis type 2 associated Schwannomatosis
• Segmented volumetric analysis
• Tumor Growth
• Linear measurements