Table 3 The use of the callosal angle 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 |
|---|---|---|---|---|---|---|
Mantovani et al. [33] | n = 62 | •Callosal angle: level of the posterior commissure orthogonal to the anterior commissure-posterior commissure (ACPC) line •Anterior callosal angle: at the level of the anterior commissure orthogonal to ACPC line | •CA: 59.5° •ACA: 112° | •3 T MRI | •Coronal plane | •Mean ACA was higher than mean CA, 103.6° ± 14.2° vs 58.9° ± 16.1° (p < 0.001) •Neither CA or ACA were found to significantly predict mRs or INPHGS outcome ACA: •There was a negative correlation between ACA and Tinetti total score (r = -0.306, p < 0.05) •Mean ACA in SR patients was smaller than SNR patients, (98.3° ± 11.4° and 108.6° ± 15.1° respectively) •Mean ACA was significantly smaller in those with reduced fall risk post shunt •Using a cutoff has a Youden’s Index = 0.344. The OR for ACA between SR and SNR is 2.97 (95% CI 1.04–8.5), CA: •There were no significant differences between SR. Values not given •There was no effect of CA size on fall risk post shunt •Using a cutoff shows Youden’s Index = 0.327. The OR between SR and SNR is 2.15 (95% CI 1.03–4.52) |
Virhammar et al., 2014 [60] | n = 108 | •Angle between lateral ventricles through the posterior commissure | •N/A | •MRI. 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 | •Coronal plane, image taken perpendicular to the anterior/ posterior commissure plane | •OR between SR and SNR: 0.57[(0.36–0.91) p = 0.017] |
Virhammar et al., 2014 [59] Callosal angle only | n = 108 | •Angle between the lateral ventricles through the posterior commissure | •63° | •MRI 3D T1-weighted images. Ten (9%) on 3-T, 75 (69%) on 1.5-T, 16 (15%) on 1-T, and 8 (7%) on 0.5-T | •Coronal plane through posterior commissure, perpendicular to the anterior commissure -Posterior commissure plane | •CA was significantly smaller in SR [59° (95% CI 56°–63°)] than SNR [68° ( •95% CI 61°–75°)] (p < 0.05) •Multivariate analysis: Smaller CA was significantly associated SR (OR 0.97, [95% CI 0.94–0.99], p < 0.05) Cutoff: Sensitivity: 0.67, Specificity:0.65, Youden’s index: 0.33 •TP: 55, TN: 18, FP: 9, FN:27. N = 109 •Weak inverse correlation between EI and CA (r = -0.23, p < 0.05) |
Narita et al. [41] | n = 103 | •Angle between the left and right corpus callosum | •N/A | •3D T1-weighted MRI obtained with a Signa 1.5 T MR imaging unit | •Coronal plane at the posterior commissure | •Simple linear regression analysis showed significant association between CA and MMSE improvement (B = − 0.04, R2 = 0.08, p = .035). There was no significant association between CA and Total score, gait cognitive or urinary subjections or TUG (B = − 0.02, − 0.01, − 0.01, − 0.01, − 0.12 respectively) |
Hong et al. [20] | n = 31 | •Angle between the lateral ventricles | •N/A | •3.0 Tesla MRI scanner was used to gain Axial fluid-attenuated inversion recovery (FLAIR), T2- weighted images, T1-weighted images, and coronal T1-weighted images | •Coronal plane through posterior commissure, perpendicular to the anterior commissure -Posterior commissure plane | •Difference in mean CA in SR: 75.2 ± 21.7 and in SNR groups: 88.3 ± 18.2 was not significant (p = 0.109). No other statistical analysis was performed |
Agerskov et al. [2] | n = 168 | •N/A | •N/A | •MRI 1.5 T. T1-weighted images | •Coronal plane at level of the posterior commissure | •All patients had CA < 90° •There was no difference in CA findings between SR (median 68°) and SNR (median 69°) [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 0.17 |
Grahnke et al. [16] | n = 72 | •Angle at the level of midpoint of corpus collosum | •105.4° | •CT or MRI | •Mid-sagittal plane, parallel to floor of 4th ventricle | •Mean CA in SR was 108.4 (SD: 16.8) while SNR was 117.6 (SD: 14.2), p = 0.030. Diagnostic accuracy AUC of 0.64 95% CI (0.50–0.78). Cutoff of 105.4 has sensitivity 0.415 and a specificity of 0.87. A patient is 4% more likely to have post-shunt benefit for every degree CA is lower: OR (unadjusted) 0.96 [(95% CI:0.93–0.998) p = 0.037], adjusted OR: 0.96 [(95% CI: 0.93–0.997) p = 0.036] •TP: 19, TN:23, FP:4, FN:26 |
Black [5] | n = 62 | •Angle of the junction of frontal horn roofs | •120° | •Pneumoencephalogram | •AP projection | •There was no significant difference in CA between SR and SNR. The cutoff had a sensitivity of 50%, specificity of 60%, PPV of 42.9% and NPV of 66.7%. TP:3, FP:4, TN:6, FN:3 |