Ventricular volumetry and free-water corrected diffusion tensor imaging of the anterior thalamic radiation in idiopathic normal pressure hydrocephalus - 06/06/19

Doi : 10.1016/j.neurad.2019.04.003

Asami Saito ^a,^b,^⁎ , Koji Kamagata ^a, Ryo Ueda ^d, Misaki Nakazawa ^a, Christina Andica ^a, Ryusuke Irie ^a, Madoka Nakajima ^c, Masakazu Miyajima ^c, Masaaki Hori ^a, Fumiaki Tanaka ^b, Hajime Arai ^c, Shigeki Aoki ^a
^a Department of Radiology, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
^b Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9, Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
^c Department of Neurosurgery, Juntendo University School of Medicine, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
^d Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10, Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan

^⁎Corresponding author at: Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, 3-9, Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan.Department of Neurology and Stroke MedicineYokohama City University Graduate School of Medicine3-9, FukuuraKanazawa-kuYokohama236-0004Japan

En prensa. Pruebas corregidas por el autor. Disponible en línea desde el Thursday 06 June 2019
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Abstract

Background and purpose

The pathophysiology of idiopathic normal pressure hydrocephalus (iNPH) has not been completely clarified. We investigated the brain structure in iNPH using automatic ventricular volumetry, single-tensor diffusion tensor imaging (DTI) and bi-tensor free-water (FW) imaging analyses while focusing on cognitive impairments before and after lumboperitoneal shunt surgery.

Materials and methods

This retrospective study included 12 iNPH patients with structural magnetic resonance imaging (MRI) and diffusion MRI (dMRI) on a 3T-MRI scanner who underwent neuropsychological assessments before and after shunting and 8 healthy controls. Ventricular volumetry was conducted on structural MRI datasets using FreeSurfer. Ventricular volume was compared pre- and postoperatively. Correlation analyses were performed between ventricular volume or volume change and neuropsychological scores or score change. Tract-based spatial statistics were performed using dMRI datasets for group analyses between iNPH and controls and between pre- and post-surgery iNPH patients and for correlation analyses using neuropsychological scores. Tract-specific analyses were performed in the anterior thalamic radiation (ATR), followed by comparison and correlation analyses.

Results

The third ventricular volume was significantly decreased after shunting; its volume reduction negatively correlated with a neuropsychological improvement. Compared with controls, iNPH patients had lower fractional anisotropy and higher axial, radial, and mean diffusivities, and FW in the periventricular white matter including ATR, resulting in no difference in FW-corrected indices. Single-tensor DTI indices partially correlated with neuropsychological improvements, while FW-corrected indices had no correlations.

Conclusion

Third ventricle enlargement is possibly linked to cognitive impairment and FW imaging possibly provides better white matter characterization in iNPH.

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Abbreviations : AD, ATR, ADT, CSF, CST, DTI, FA, FAT, FAB, FSL, FW, FWE, MD, MDT, MMSE, MPRAGE, MRI, RD, RDT, TBSS, TIV, TSA, VOI

Keywords : Idiopathic normal pressure hydrocephalus, Cognitive impairment, Ventricular volumetry, Diffusion tensor imaging, Free-water imaging, Anterior thalamic radiation