AUTHOR=Kikuta Junko , Kamagata Koji , Taoka Toshiaki , Takabayashi Kaito , Uchida Wataru , Saito Yuya , Andica Christina , Wada Akihiko , Kawamura Kaito , Akiba Chihiro , Nakajima Madoka , Miyajima Masakazu , Naganawa Shinji , Aoki Shigeki 

TITLE=Water Diffusivity Changes Along the Perivascular Space After Lumboperitoneal Shunt Surgery in Idiopathic Normal Pressure Hydrocephalus

JOURNAL=Frontiers in Neurology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2022.843883

DOI=10.3389/fneur.2022.843883

ISSN=1664-2295

ABSTRACT=<sec><title>Background</title><p>The aim of this study was to evaluate the water diffusivity changes along the perivascular space after lumboperitoneal shunt (LPS) surgery in idiopathic normal pressure hydrocephalus.</p></sec><sec><title>Methods</title><p>Nine patients diagnosed with idiopathic normal pressure hydrocephalus (iNPH; three men and six women, mean age ± SD = 75.22 ± 5.12 years) according to the guidelines for iNPH in Japan were included in the study. Post-LPS surgery, six patients with iNPH who exhibited improvement in symptoms were defined as responder subjects, while three patients with iNPH who did not were defined as non-responder subjects. We calculated the mean analysis along the perivascular space (ALPS) index of the left and right hemispheres and compared the differences between pre- and post-LPS surgery mean ALPS indices in iNPH patients. In the responder or non-responder subjects, the mean ALPS indices in the pre- and post-operative iNPH groups were compared using Wilcoxon signed-rank tests. Next, correlation analyses between pre- and post-operation changes in the mean ALPS index and clinical characteristics were conducted.</p></sec><sec><title>Results</title><p>The mean ALPS index of the post-operative iNPH group was significantly higher than that of the pre-operative iNPH group (<italic>p</italic> = 0.021). In responder subjects, the mean ALPS index of the post-operative iNPH group was significantly higher than that of the pre-operative iNPH group (<italic>p</italic> = 0.046). On the other hand, in the non-responder subjects, the mean ALPS index of the post-operative iNPH group was not significantly different compared to the pre-operative iNPH group (<italic>p</italic> = 0.285). The mean ALPS index change was not significantly correlated with changes in the Mini-Mental State Examination (MMSE) score (<italic>r</italic> = −0.218, <italic>p</italic> = 0.574), Frontal Assessment Battery (FAB) score (<italic>r</italic> = 0.185, <italic>p</italic> = 0.634), Trail Making Test A (TMTA) score (<italic>r</italic> = 0.250, <italic>p</italic> = 0.516), and Evans' index (<italic>r</italic> = 0.109, <italic>p</italic> = 0.780). In responder subjects, the mean ALPS index change was significantly correlated with Evans' index in pre-operative patients with iNPH (<italic>r</italic> = 0.841, <italic>p</italic> = 0.036).</p></sec><sec><title>Conclusion</title><p>This study demonstrates the improved water diffusivity along perivascular space in patients with iNPH after LPS surgery. This could be indicative of glymphatic function recovery following LPS surgery.</p></sec>