Texture Analysis of High b-Value Diffusion-Weighted Imaging for Evaluating Consistency of Pituitary Macroadenomas

Preoperative evaluation of the consistency of pituitary macroadenomas is important for neurosurgeons to prepare the surgical plan.

To evaluate the diagnostic performance of texture analysis (TA) of diffusion-weighted imaging (DWI) at a standard b-value (b = 1000 s/mm² ) and a high b-value (b = 2000 s/mm² ) for their ability to assess the tumor consistency of pituitary macroadenomas.

Retrospective.

Fifty patients with histologically confirmed pituitary macroadenomas were classified as soft (n = 37) or hard (n = 13) types.

Coronal T₂ -weighted imaging (T₂ WI), Readout Segmentation of Long Variable Echo-trains (RESOLVE) DWI at b = 1000 s/mm² and b = 2000 s/mm² were acquired with 3.0T MRI.

The corresponding apparent diffusion coefficient (ADC) maps (ADC₁₀₀₀ and ADC₂₀₀₀ ) were registered to T₂ WI. Regions of interest (ROIs) were manually drawn along the solid part of the tumor from the coregistered T₂ WI-ADC images. The texture parameters from T₂ WI, ADC₁₀₀₀ , and ADC₂₀₀₀ were acquired.

The texture parameters were compared between the two types by using unpaired Student's t-test. Receiver operating characteristic (ROC) curves and logistic regression analyses were used to assess their diagnostic performance.

Significant differences in TA parameters of ADC₁₀₀₀ and ADC₂₀₀₀ were observed between soft and hard types (P < 0.05 for all), whereas the TA of T₂ WI resulted in no significant difference (P > 0.05 for all). TA of ADC₂₀₀₀ provided a superior diagnostic performance compared with that of ADC₁₀₀₀ (P = 0.038). A combination of mean value and entropy of ADC₂₀₀₀ yielded an AUC, a sensitivity, and a specificity of 0.911, 78.4% and 92.3%, respectively.

TA of ADC values were useful for assessing the tumor consistency of pituitary macroadenomas. ADC₂₀₀₀ may facilitate better type discrimination.

3 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1507-1513.