Table 2 The use of Evan’s Index on MRI and CT for prediction of shunt response in iNPH
Study | Sample size | Radiological methodology | Cutoff specification | Image specification | Image plane | Main reported outcomes |
|---|---|---|---|---|---|---|
Narita et al. [41] | n = 103 | •Ratio between max diameter of the frontal horns of lateral ventricles to the max skull inner diameter | N/A | •3D T1-weighted MRI obtained with a Signa 1.5 T MR imaging unit | •Transverse plane | •No significant association between Evan’s Index and post-surgical improvement reported. (Regression coefficient for total score, gait, cognitive, urinary subsections, TUG and MMSE was 7.34, 1.00, 0.97, 5.37, 60.96, 9.22 respectively p > 0.1) |
Virhammar et al., 2014[60] | n = 108 | •Ratio between max diameter of the frontal horns of lateral ventricles to the max skull inner diameter | N/A | •T2 Flair, T1-weighted MRI •9% of patients on 3 T scanner; 70% on a 1.5 T scanner, 14% on a 1 T scanner and 7% on a 0.5 T scanner | •Transverse plane | •OR between SR and SNR: 1.57 (0.97–2.52), p = 0.064) |
Hong et al. [20] | n = 31 | •Ratio between the max diameter of frontal horns of the lateral ventricles and the max inner diameter of the skull | N/A | •3.0 Tesla MRI scanner was used to gain axial FLAIR, T2- weighted images, T1-weighted images, and coronal T1-weighted images | •Transverse plane | •There was no significant difference in Evan’s Index between SR and SNR. SR had mean Evan’s Index of 0.37 ± 0.04 while SNR had mean Evan’s Index 0.37 ± 0.03 (p = 0.77) |
Agerskov et al. [2] | n = 168 | •Ratio between max diameter of frontal horns and the max inner skull diameter | N/A | •MRI 1.5 T •Trans-axial T1-weighted images | •Transverse plane in slice above the foramen of Monro | •All patients had Evan’s Index > 0.3 •There was no difference in Evan’s Index findings between SR (median 0.4) and SNR (median 0.39) [p > 0.05] and it could not be used to predict SR in multivariate logistical analysis •Its non-significant correlation coefficient with the composite score was -0.09 |
Wu et al. [61] | n = 41 | •Not given | N/A | •High-resolution T1-weighted MRI | •Not given | •The model predictions using Evan’s Index alone with co-variates mentioned in methodology showed a low correlation with the ground truth (r = 0.48 for the Tinetti and r = 0.80 for MMSE) •When the co-variates were removed from the input, the prediction accuracy was 0.42 and 0.46 for the Tinetti and MMSE respectively |