Value of MRI-based semi-quantitative structural neuroimaging in predicting the prognosis of patients with idiopathic normal pressure hydrocephalus after shunt surgery.

OBJECTIVES: To explore the value of structural neuroimaging in predicting the prognosis of shunt surgery for idiopathic normal-pressure hydrocephalus (iNPH) using two different standard semi-quantitative imaging scales. METHODS: A total of 47 patients with iNPH who underwent shunt surgery at our hospital between 2018 and 2020 were included in this study. The modified Rankin Scale (mRS) and iNPH grading scale (iNPHGS) were used to evaluate and quantify the clinical symptoms before and after shunt surgery. The disproportionately enlarged subarachnoid space hydrocephalus (DESH) and iNPH Radscale scores were used to evaluate the preoperative MR images. The primary endpoint was improvement in the mRS score a year after surgery, and the secondary endpoint was the iNPHGS after 1 year. The preoperative imaging features of the improved and non-improved groups were compared. RESULTS: The rates of the primary and secondary outcomes were 59.6% and 61.7%, respectively, 1 year after surgery. There were no significant differences in preoperative DESH score, iNPH Radscale, Evans' index (EI), or callosal angle (CA) between the improved and non-improved groups. Significant correlations were observed between the severity of gait disorder and EI and the CA. CONCLUSIONS: The value of structural neuroimaging in predicting the prognosis of shunt surgery is limited, and screening for shunt surgery candidates should not rely only on preoperative imaging findings. KEY POINTS: • Early shunt surgery can significantly improve the clinical symptoms and prognosis of patients with idiopathic normal-pressure hydrocephalus (iNPH). • Structural imaging findings have limited predictiveness for the prognosis of patients with iNPH after shunt surgery. • Patients should not be selected for shunt surgery based on only structural imaging findings.

Idiopathic normal pressure hydrocephalus: Validation of the DESH score as a prognostic tool for shunt surgery response.

OBJECTIVE: Several radiological markers have been linked to clinical improvement after shunt surgery for idiopathic normal pressure hydrocephalus (iNPH). However, iNPH has no pathognomonic feature, and patients are still diagnosed as probable, possible, or unlikely cases based on clinical symptoms, imaging findings, and invasive supplementary tests. The predictive value of the disproportionately enlarged subarachnoid space hydrocephalus (DESH) score is not yet conclusively determined, but it might offer a more accurate diagnostic method. The aim of the present retrospective cohort study was to validate the predictive power of the DESH score for clinical improvement after shunt surgery in iNPH patients. METHODS: We retrospectively obtained presurgical MRI and/or CT scans from 71 patients with iNPH who underwent ventriculoperitoneal shunt surgery. Radiological images were evaluated for Evans index (EI), corpus callosal angle (CA), tight high convexity (THC), Sylvian fissure dilation, and focal sulci dilation. These markers were aggregated to determine the DESH score. Patient journal entries were used to subjectively determine the extent of improvement in gait function, urinary incontinence, and/or cognition as a measure of shunt surgery response. RESULTS: Multiple logistic regression analysis, controlling for age and sex (α = 0.05), showed that DESH score was significantly correlated (OR 1.77) with subjective shunt-surgery response at a minimum of 1-month follow-up. Patients with higher DESH scores were more likely to have a favorable response to shunt surgery. CONCLUSION: Aggregating radiological markers into the DESH score is useful for predicting shunt responders among iNPH patients and can aid the selection of patients for surgery. These findings provide further support for the DESH score as a diagnostic tool for iNPH.

Utility of MRI-based disproportionately enlarged subarachnoid space hydrocephalus scoring for predicting prognosis after surgery for idiopathic normal pressure hydrocephalus: clinical research.

OBJECTIVE The presence of disproportionately enlarged subarachnoid space hydrocephalus (DESH) on brain imaging is a recognized finding of idiopathic normal pressure hydrocephalus (iNPH), but the features of DESH can vary across patients. The aim of this study was to evaluate the utility of MRI-based DESH scoring for predicting prognosis after surgery. METHODS In this single-center, retrospective cohort study, the DESH score was determined by consensus between a group of neurosurgeons, neurologists, and a neuroradiologist based on the preoperative MRI findings of the patients with suspected iNPH. The DESH score was composed of the following 5 items, each scored from 0 to 2 (maximum score 10 points): ventriculomegaly, dilated sylvian fissures, tight high convexity, acute callosal angle, and focal sulcal dilation. The association between the DESH score and improvement of the scores on the modified Rankin Scale (mRS), iNPH Grading Scale (iNPHGS), Mini-Mental State Examination (MMSE), Trail Making Test-A (TMT-A), and Timed 3-Meter Up and Go Test (TUG-t) was examined. The primary end point was improvement in the mRS score at 1 year after surgery, and the secondary outcome measures were the iNPHGS, MMSE, TMT-A, and TUG-t scores at 1 year after surgery. Improvement was determined as improvement of 1 or more levels on mRS, ≥ 1 point on iNPHGS, ≥ 3 points on MMSE, a decrease of > 30% on TMT-A, and a decrease of > 10% on TUG-t. RESULTS The mean DESH score for the 50 patients (mean age 77.6 ± 5.9 years) reviewed in this study was 5.58 ± 2.01. The mean rate of change in the mRS score was -0.50 ± 0.93, indicating an inverse correlation between the DESH score and rate of change in the mRS score (r = -0.749). Patients who showed no improvement in mRS score tended to have a low DESH score as well as low preoperative MMSE and TMT-A scores. There were no differences in the areas of deep white matter hyperintensity and periventricular hyperintensity on the images between patients with and without an improved mRS score (15.6% vs 16.7%, respectively; p = 1.000). The DESH score did differ significantly between patients with and without improved scores on the iNPHGS (6.39 ± 1.76 vs 4.26 ± 1.69, respectively; p < 0.001), MMSE (6.63 ± 1.82 vs 5.09 ± 1.93; p = 0.010), TMT-A (6.32 ± 1.97 seconds vs 5.13 ± 1.93 seconds; p = 0.042), and TUG-t (6.48 ± 1.81 seconds vs 4.33 ± 1.59 seconds; p < 0.001). CONCLUSIONS MRI-based DESH scoring is useful for the prediction of neurological improvement and prognosis after surgery for iNPH.