2025 Proffered Presentations
S153: PREDICTING OLFACTORY BULB INFILTRATION AND MORPHOLOGICAL CHANGES IN OLFACTORY NEUROBLASTOMA USING MRI
Teppei Takeda1; Yasine Mirmozaffari2; Kazuhiro Omura1; Adam J Kimple2; Brent A Senior2; Charles S Ebert2; Cristine Klatt-Cromwell2; Brian D Thorp2; 1The Jikei University School of Medichine; 2University of North Carolina - Chapel Hill.
Background and Purpose: Olfactory neuroblastoma (ONB) is a rare malignant tumor originating in the olfactory epithelium. The extent of olfactory bulb infiltration significantly impacts ONB staging, making imaging-based prediction crucial for treatment planning. This study aims to predict olfactory bulb infiltration by evaluating volumetric and morphological changes using magnetic resonance imaging (MRI).
Methods: We collected preoperative MRI scans and postoperative pathology reports from 46 ONB patients. High-resolution coronal T1-weighted and T2-weighted images were analyzed to assess olfactory bulb morphology and volume. Quantitative measurements included olfactory bulb volume and maximum cross-sectional area (Figure 1). Infiltration was classified based on pathological findings. Sensitivity models were developed for volume, maximum cross-sectional area, and tumor/non-tumor side ratios for both volume and area.
Results: Significant volumetric and cross-sectional area changes were observed in infiltrated olfactory bulbs compared to non-infiltrated ones (Figure 2). The diagnostic models showed strong performance, with area under the ROC curve values ranging from 0.878 to 0.971 (Figure 3). Optimal cut-off values were identified: olfactory bulb volume ≥60 mm³, maximum cross-sectional area ≥9.5 mm², volume ratio (tumor/non-tumor) ≥175%, and cross-sectional area ratio (tumor/non-tumor) ≥175%, all demonstrating high sensitivity and specificity.
Conclusion: MRI effectively assesses olfactory bulb morphological changes and infiltration in ONB, aiding in treatment planning. Further studies with larger cohorts are required to validate these findings and refine MRI-based evaluation criteria.
Figure 1 Measurement of Olfactory Bulb (OB) Cross-sectional Area and Volume in MRI
In MRI, OB cross-sectional areas were measured by manual segmentation of coronal slices passing through the OB. OB volume was calculated by manually outlining the OB on each coronal slice (cross-sectional area in mm²), summing all the outlined surfaces, and multiplying by the slice thickness, resulting in volume in cubic millimeters.
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Figure 2 Comparison of Infiltrated and Non-Infiltrated Olfactory Bulbs Based on Volume and Cross-sectional Area Using MRI
Figure 3 ROC Curves for Diagnostic Models Using Volume and Area Metrics to Predict Olfactory Bulb Infiltration in Olfactory Neuroblastoma
