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

Abstract

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.

Absence of Disproportionately Enlarged Subarachnoid Space Hydrocephalus, a Sharp Callosal Angle, or Other Morphologic MRI Markers Should Not Be Used to Exclude Patients with Idiopathic Normal Pressure Hydrocephalus from Shunt Surgery

“…Specifically, a small callosal angle or the finding of DESH was not associated with a favorable outcome. The lack of correlation between morphologic MR imaging markers and postoperative improvement corroborates some earlier studies 9,12,25 and contradicts other publications that have reported significant associations between postoperative improvement and the presence of a narrow callosal angle, 16 the DESH phenomenon, 15,16 and dilation of the temporal horns. 8 A possible explanation for the different results regarding the predictive value of morphologic imaging markers reported here compared with many earlier studies could be the selection of patients.…”

“…Many of the previous studies have used the modified Rankin Scale, which was developed for use in patients with stroke and does not measure symptom severity in iNPH but instead provides a general measure of disability. 27 Other groups have applied outcome scales based on ordinal or nominal ratings, 8,10,15 making a direct comparison with the results presented here more difficult. To maximize the sensitivity and validity of results, one should use quantitative outcome measures if possible.…”

“…7 The use of morphologic MR imaging markers for selecting appropriate shunt surgery candidates has been investigated, but results vary; the use of these markers for predictive purposes is still disputed. [8][9][10][11][12] DESH 13 has won support as a prognostic marker, 14 most recently by Shinoda et al, 15 who developed a 10-point grading scale to aid in patient selection for surgery. Virhammar et al 8,16 reported that the presence of DESH, a narrow callosal angle (Ͻ63°), and dilation of the temporal horns were predictors of good surgical outcome.…”

Progressive supranuclear palsy often develops idiopathic normal pressure hydrocephalus‐like magnetic resonance imaging features

“…Some recent studies attempted to evaluate DESH quantitatively. MRI-based DESH score, one of the quantitative analyses, is useful to predict shunt responsiveness in iNPH patients [11]. DESH score is composed of the following factors, each scored from 0 to 2 (maximum score 10): ventriculomegaly, dilated sylvian fissures, tight high convexity, acute callosal angle (CA) and focal sulcal dilation (Table S1).…”

“…DESH score is composed of the following factors, each scored from 0 to 2 (maximum score 10): ventriculomegaly, dilated sylvian fissures, tight high convexity, acute callosal angle (CA) and focal sulcal dilation (Table S1). The literature suggests that a high DESH score has a positive predictive value related to responsiveness to shunt operation [11].…”