Per Kristian Eide

• Ringstad, Geir & Eide, Per Kristian (2024). Glymphatic-lymphatic coupling: assessment of the evidence from magnetic resonance imaging of humans. Cellular and Molecular Life Sciences (CMLS). ISSN 1420-682X. 81(1). doi: 10.1007/s00018-024-05141-2.
• Eide, Per Kristian & Ringstad, Geir (2024). Functional analysis of the human perivascular subarachnoid space. Nature Communications. ISSN 2041-1723. 15(1). doi: 10.1038/s41467-024-46329-1.
• Døving, Mats; Stray, August; Anandan, Steven; Eide, Per Kristian; Skogen, Karoline & Koht, Jeanette (2024). En kvinne i 40-årene med smerter i øret. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 144(1), s. 1–8. doi: 10.4045/tidsskr.23.0543.
• Frič, Radek; Bryne, Eline; Warsza, Bogna; Due-Tønnessen, Bernt Johan & Eide, Per Kristian (2024). Preoperative estimation of intracranial compliance in symptomatic children with Chiari malformation type 1: impact on outcome and risk of complications. Acta Neurochirurgica. ISSN 0001-6268. 166(1). doi: 10.1007/s00701-024-05897-3.
• Eide, Per Kristian; Lashkarivand, Aslan; Pripp, Are Hugo; Valnes, Lars Magnus; Hovd, Markus & Ringstad, Geir [Vis alle 8 forfattere av denne artikkelen] (2023). Mechanisms behind changes of neurodegeneration biomarkers in plasma induced by sleep deprivation. Brain Communications. ISSN 2632-1297. 5(6). doi: 10.1093/braincomms/fcad343. Fulltekst i vitenarkiv
• Sperre, Anette; Karsrud, Ina; Rodum, Anja; Lashkarivand, Aslan; Valnes, Lars Magnus & Ringstad, Geir [Vis alle 7 forfattere av denne artikkelen] (2023). Prospective Safety Study of Intrathecal Gadobutrol in Different Doses. American Journal of Neuroradiology. ISSN 0195-6108. 44(5), s. 511–516. doi: 10.3174/ajnr.A7841.
• Melin, Erik; Pripp, Are Hugo; Eide, Per Kristian & Ringstad, Geir (2023). In vivo distribution of cerebrospinal fluid tracer in human upper spinal cord and brain stem. JCI Insight. ISSN 2379-3708. 8(23). doi: 10.1172/jci.insight.173276. Fulltekst i vitenarkiv
• Vera Quesada, Cesar Luis; Shreyas, Rao; Torp, Reidun & Eide, Per Kristian (2023). Widespread distribution of lymphatic vessels in human dura mater remote from sinus veins. Frontiers in Cell and Developmental Biology. ISSN 2296-634X. 11. doi: 10.3389/fcell.2023.1228344. Fulltekst i vitenarkiv
• Lashkarivand, Aslan & Eide, Per Kristian (2023). Brain Sagging Dementia. Current Neurology and Neuroscience Reports. ISSN 1528-4042. 23(10), s. 593–605. doi: 10.1007/s11910-023-01297-9. Fulltekst i vitenarkiv
• Vinje, Vegard; Zapf, Bastian; Ringstad, Geir; Eide, Per Kristian; Rognes, Marie Elisabeth & Mardal, Kent-Andre (2023). Human brain solute transport quantified by glymphatic MRI-informed biophysics during sleep and sleep deprivation. Fluids and Barriers of the CNS. ISSN 2045-8118. 20(1), s. 1–15. doi: 10.1186/s12987-023-00459-8. Fulltekst i vitenarkiv
• Warsza, Bogna; Due-Tønnessen, Pernille; Due-Tønnessen, Paulina; Pripp, Are Hugo; Ringstad, Geir & Eide, Per Kristian (2023). Prevalence of pineal cysts in healthy individuals: Emphasis on size, morphology and pineal recess crowding. Journal of the Neurological Sciences. ISSN 0022-510X. 453. doi: 10.1016/j.jns.2023.120801. Fulltekst i vitenarkiv
• Ringstad, Geir; Valnes, Lars Magnus; Vatnehol, Svein Are Sirirud; Pripp, Are Hugo & Eide, Per Kristian (2023). Prospective T1 mapping to assess gadolinium retention in brain after intrathecal gadobutrol. Neuroradiology. ISSN 0028-3940. 65(9), s. 1321–1331. doi: 10.1007/s00234-023-03198-7. Fulltekst i vitenarkiv Vis sammendrag

  Purpose A possible pathway behind gadolinium retention in brain is leakage of contrast agents from blood to cerebrospi- nal fluid and entry into brain along perivascular (glymphatic) pathways. The object of this study was to assess for signs of gadolinium retention in brain 4 weeks after intrathecal contrast enhanced MRI. Methods We prospectively applied standardized T1 mapping of the brain before and 4 weeks after intrathecal administration of 0.5 mmol gadobutrol in patients under work-up of cerebrospinal fluid circulation disorders. Due to methodological limita- tions, a safety margin for percentage change in T1 time was set to 3%. Region-wise differences were assessed by pairwise comparison using t-tests and forest plots, and statistical significance was accepted at .05 level (two-tailed). Results In a cohort of 76 participants (mean age 47.2 years ± 17.9 [standard deviation], 47 women), T1 relaxation times remained unchanged in cerebral cortex and basal ganglia 4 weeks after intrathecal gadobutrol. T1 was reduced from 1082 ± 46.7 ms to 1070.6 ± 36.5 ms (0.98 ±2.9%) (mean [standard deviation]) (p=0.001) in white matter, thus within the pre- defined 3% safety margin. The brain stem and cerebellum could not be assessed due to poor alignment of posterior fossa structures at scans from different time points. Conclusion Gadolinium retention was not detected in the cerebral hemispheres 4 weeks after an intrathecal dose of 0.5 mmol gadobutrol, implying that presence of contrast agents in cerebrospinal fluid is of minor importance for gadolinium retention in brain.

• Vera Quesada, Cesar Luis; Shreyas, Rao; Torp, Reidun & Eide, Per Kristian (2023). Immunohistochemical visualization of lymphatic vessels in human dura mater: methodological perspectives. Fluids and Barriers of the CNS. ISSN 2045-8118. 20(1). doi: 10.1186/s12987-023-00426-3. Fulltekst i vitenarkiv
• Eide, Per Kristian; Lashkarivand, Aslan; Pripp, Are Hugo; Valnes, Lars Magnus; Hovd, Markus Herberg & Ringstad, Geir [Vis alle 8 forfattere av denne artikkelen] (2023). Plasma neurodegeneration biomarker concentrations associate with glymphatic and meningeal lymphatic measures in neurological disorders. Nature Communications. ISSN 2041-1723. 14, s. 1–14. doi: 10.1038/s41467-023-37685-5. Fulltekst i vitenarkiv
• Frič, Radek; Ringstad, Geir & Eide, Per Kristian (2023). Low versus High Intracranial Compliance in Adult Patients with Chiari Malformation Type 1–Comparison of Long-Term Outcome After Tailored Treatment. World Neurosurgery. ISSN 1878-8750. 173, s. e699–e707. doi: 10.1016/j.wneu.2023.02.134. Fulltekst i vitenarkiv
• Melin, Erik; Ringstad, Geir; Valnes, Lars Magnus & Eide, Per Kristian (2023). Human parasagittal dura is a potential neuroimmune interface. Communications Biology. ISSN 2399-3642. 6(1), s. 1–8. doi: 10.1038/s42003-023-04634-3. Fulltekst i vitenarkiv
• Eide, Per Kristian; Lindstrøm, Erika Kristina; Pripp, Are Hugo; Valnes, Lars Magnus & Ringstad, Geir (2023). Physiological alterations of pineal recess crowding in symptomatic non-hydrocephalic pineal cysts. Brain Communications. ISSN 2632-1297. 5(2). doi: 10.1093/braincomms/fcad078. Fulltekst i vitenarkiv
• Thavarajasingam, Santhosh G.; El-Khatib, Mahmoud; Vemulapalli, Kalyan; Iradukunda, Hector A. Sinzinkayo; K, Sajeenth Vishnu & Borchert, Robin [Vis alle 8 forfattere av denne artikkelen] (2022). Radiological predictors of shunt response in the diagnosis and treatment of idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis. Acta Neurochirurgica. ISSN 0001-6268. s. 1–51. doi: 10.1007/s00701-022-05402-8. Fulltekst i vitenarkiv
• Aukrust, Camilla Grøver; Paulsen, Anne Henriette; Uche, Enoch Ogbonnaya; Kamalo, Patrick Dongosolo; Sandven, Irene & Fjeld, Heidi E [Vis alle 8 forfattere av denne artikkelen] (2022). Aetiology and diagnostics of paediatric hydrocephalus across Africa: a systematic review and meta-analysis. The Lancet Global Health. ISSN 2572-116X. 10(12), s. e1793–e1806. doi: 10.1016/S2214-109X(22)00430-2. Fulltekst i vitenarkiv
• Eide, Per Kristian; Sorteberg, Angelika; Nome, Terje; Rønning, Pål Andre & Sorteberg, Wilhelm (2022). Early surgical versus endovascular repair of ruptured blood-blister aneurysm of the internal carotid artery: a single-center 20-year experience. Journal of Neurosurgery. ISSN 0022-3085. 137(6), s. 1766–1775. doi: 10.3171/2022.3.JNS2216.
• Eide, Per Kristian (2022). Cellular changes at the glia-neuro-vascular interface in definite idiopathic normal pressure hydrocephalus. Frontiers in Cellular Neuroscience. ISSN 1662-5102. 16, s. 1–18. doi: 10.3389/fncel.2022.981399. Fulltekst i vitenarkiv
• Hornkjøl, Martin; Valnes, Lars Magnus; Ringstad, Geir; Rognes, Marie Elisabeth; Eide, Per Kristian & Mardal, Kent-Andre [Vis alle 7 forfattere av denne artikkelen] (2022). CSF circulation and dispersion yield rapid clearance from intracranial compartments. Frontiers in Bioengineering and Biotechnology. ISSN 2296-4185. 10, s. 1–14. doi: 10.3389/fbioe.2022.932469. Fulltekst i vitenarkiv
• Eide, Per Kristian & Hansson, Hans-Arne (2022). A New Perspective on the Pathophysiology of Idiopathic Intracranial Hypertension: Role of the Glia-Neuro-Vascular Interface. Frontiers in Molecular Neuroscience. ISSN 1662-5099. 15, s. 1–24. doi: 10.3389/fnmol.2022.900057. Fulltekst i vitenarkiv
• Lashkarivand, Aslan & Eide, Per Kristian (2022). Brain Sagging Dementia-Diagnosis, Treatment, and Outcome: A Review. Neurology. ISSN 0028-3878. 98(19), s. 798–805. doi: 10.1212/WNL.0000000000200511.
• Zapf, Bastian; Haubner, Johannes; Kuchta, Miroslav; Ringstad, Geir; Eide, Per Kristian & Mardal, Kent-Andre (2022). Investigating molecular transport in the human brain from MRI with physics-informed neural networks. Scientific Reports. ISSN 2045-2322. 12(15475), s. 1–12. doi: 10.1038/s41598-022-19157-w. Fulltekst i vitenarkiv
• Hovd, Markus Herberg; Mariussen, Espen; Uggerud, Hilde Thelle; Lashkarivand, Aslan; Christensen, Hege & Ringstad, Geir [Vis alle 7 forfattere av denne artikkelen] (2022). Population pharmacokinetic modeling of CSF to blood clearance: prospective tracer study of 161 patients under work-up for CSF disorders. Fluids and Barriers of the CNS. ISSN 2045-8118. 19. doi: 10.1186/s12987-022-00352-w. Fulltekst i vitenarkiv Vis sammendrag

  Background Quantitative measurements of cerebrospinal fluid to blood clearance has previously not been established for neurological diseases. Possibly, variability in cerebrospinal fluid clearance may affect the underlying disease process and may possibly be a source of under- or over-dosage of intrathecally administered drugs. The aim of this study was to characterize the cerebrospinal fluid to blood clearance of the intrathecally administered magnetic resonance imaging contrast agent gadobutrol (Gadovist, Bayer Pharma AG, GE). For this, we established a population pharmacokinetic model, hypothesizing that cerebrospinal fluid to blood clearance differs between cerebrospinal fluid diseases. Methods Gadobutrol served as a surrogate tracer for extra-vascular pathways taken by several brain metabolites and drugs in cerebrospinal fluid. We estimated cerebrospinal fluid to blood clearance in patients with different cerebrospinal fluid disorders, i.e. symptomatic pineal and arachnoid cysts, as well as tentative spontaneous intracranial hypotension due to cerebrospinal fluid leakage, idiopathic intracranial hypertension, or different types of hydrocephalus (idiopathic normal pressure hydrocephalus, communicating- and non-communicating hydrocephalus). Individuals with no verified cerebrospinal fluid disturbance at clinical work-up were denoted references. Results Population pharmacokinetic modelling based on 1,140 blood samples from 161 individuals revealed marked inter-individual variability in pharmacokinetic profiles, including differences in absorption half-life (time to 50% of tracer absorbed from cerebrospinal fluid to blood), time to maximum concentration in blood and the maximum concentration in blood as well as the area under the plasma concentration time curve from zero to infinity. In addition, the different disease categories of cerebrospinal fluid diseases demonstrated different profiles. Conclusions The present observations of considerable variation in cerebrospinal fluid to blood clearance between individuals in general and across neurological diseases, may suggest that defining cerebrospinal fluid to blood clearance can become a useful diagnostic adjunct for work-up of cerebrospinal fluid disorders. We also suggest that it may become useful for assessing clearance capacity of endogenous brain metabolites from cerebrospinal fluid, as well as measuring individual cerebrospinal fluid to blood clearance of intrathecal drugs.

• Thavarajasingam, Santhosh G.; El-Khatib, Mahmoud; Vemulapalli, Kalyan V.; Iradukunda, Hector A. Sinzinkayo; Laleye, Joshua & Russo, Salvatore [Vis alle 8 forfattere av denne artikkelen] (2022). Cerebrospinal fluid and venous biomarkers of shunt-responsive idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis. Acta Neurochirurgica. ISSN 0001-6268. 164, s. 1719–1746. doi: 10.1007/s00701-022-05154-5. Fulltekst i vitenarkiv
• Eide, Per Kristian; Lashkarivand, Aslan; Hagen-Kersten, Åsmund Aleksander; Gjertsen, Øivind; Nedregaard, Bård & Sletteberg, Ruth [Vis alle 11 forfattere av denne artikkelen] (2022). Intrathecal Contrast-Enhanced Magnetic Resonance Imaging of Cerebrospinal Fluid Dynamics and Glymphatic Enhancement in Idiopathic Normal Pressure Hydrocephalus. Frontiers in Neurology. ISSN 1664-2295. 13, s. 1–21. doi: 10.3389/fneur.2022.857328. Fulltekst i vitenarkiv Vis sammendrag

  Idiopathic normal pressure hydrocephalus (iNPH) is a neurodegenerative disease, characterized by cerebrospinal fluid (CSF) flow disturbance. Today, the only available treatment is CSF diversion surgery (shunt surgery). While traditional imaging biomarkers typically assess CSF space anatomy, recently introduced imaging biomarkers of CSF dynamics and glymphatic enhancement, provide imaging of CSF dynamics and thereby more specifically reveal elements of the underlying pathophysiology. The biomarkers address CSF ventricular reflux grade as well as glymphatic enhancement and derive from intrathecal contrast-enhanced MRI. However, the contrast agent serving as CSF tracer is administered off-label. In medicine, the introduction of new diagnostic or therapeutic methods must consider the balance between risk and benefit. To this end, we performed a prospective observational study of 95 patients with iNPH, comparing different intrathecal doses of the MRI contrast agent gadobutrol (0.10, 0.25, and 0.50 mmol, respectively), aiming at the lowest reasonable dose needed to retrieve diagnostic information about the novel MRI biomarkers. The present observations disclosed a dose-dependent enrichment of subarachnoid CSF spaces (cisterna magna, vertex, and velum interpositum) with dose-dependent ventricular reflux of tracer in iNPH, as well as dose-dependent glymphatic tracer enrichment. The association between tracer enrichment in CSF and parenchymal compartments were as well dose-related. Intrathecal gadobutrol in a dose of 0.25 mmol, but not 0.10 mmol, was at 1.5T MRI considered sufficient for imaging altered CSF dynamics and glymphatic enhancement in iNPH, even though 3T MRI provided better sensitivity. Tracer enrichment in CSF at the vertex and within the cerebral cortex and subcortical white matter was deemed too low for maintaining diagnostic information from a dose of 0.10 mmol. We conclude that reducing the intrathecal dose of gadobutrol from 0.50 to 0.25 mmol gadobutrol improves the safety margin while maintaining the necessary diagnostic information about disturbed CSF homeostasis and glymphatic failure in iNPH.

• Jacobsen, Henrik Holvin; Jørstad, Øystein Kalsnes; Moe, Morten Carsten; Petrovski, Goran; Pripp, Are Hugo & Sandell, Tiril [Vis alle 7 forfattere av denne artikkelen] (2022). Noninvasive Estimation of Pulsatile and Static Intracranial Pressure by Optical Coherence Tomography. Translational Vision Science & Technology. ISSN 2164-2591. 11(1). doi: 10.1167/tvst.11.1.31. Fulltekst i vitenarkiv
• Eide, Per Kristian; Pripp, Are Hugo; Berge, Benedikte; Hrubos-Strøm, Harald; Ringstad, Geir & Valnes, Lars Magnus (2022). Altered glymphatic enhancement of cerebrospinal fluid tracer in individuals with chronic poor sleep quality. Journal of Cerebral Blood Flow and Metabolism. ISSN 0271-678X. 42(9), s. 1676–1692. doi: 10.1177/0271678X221090747. Fulltekst i vitenarkiv Vis sammendrag

  Chronic sleep disturbance is a risk factor for dementia disease, possibly due to impaired sleep-dependent clearance of toxic metabolic by-products. We compared enrichment of a cerebrospinal fluid (CSF) tracer within brain of patients reporting good or poor sleep quality, assessed by the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Tracer enrichment in a selection of brain regions was assessed using multiphase magnetic resonance imaging up to 48 hours after intrathecal administration of the contrast agent gadobutrol (0.5 ml of 1 mmol/ml) serving as tracer. Tracer enrichment differed between patients with good (PSQI ≤5) and poor (PSQI >5) sleep quality in a cohort of non-dementia individuals (n = 44; age 42.3 ± 14.5 years), and in patients with the dementia subtype idiopathic normal pressure hydrocephalus (n = 24; age 71.0 ± 4.9 years). Sleep impairment was associated with increased CSF tracer enrichment in several brain regions. Cortical brain volume as well as entorhinal cortex thickness was reduced in the oldest cohort and was correlated with the severity of sleep disturbance and the degree of cortical tracer enrichment. We suggest chronic sleep disturbance is accompanied by altered glymphatic function along enlarged perivascular spaces.

• Ringstad, Geir & Eide, Per Kristian (2021). Molecular trans-dural efflux to skull bone marrow in humans with CSF disorders. Brain. ISSN 0006-8950. 145(4), s. 1464–1472. doi: 10.1093/brain/awab388. Fulltekst i vitenarkiv
• Eide, Per Kristian (2021). Familial occurrence of classical and idiopathic trigeminal neuralgia . Journal of the Neurological Sciences. ISSN 0022-510X. 434, s. 1–6. doi: 10.1016/j.jns.2021.120101. Fulltekst i vitenarkiv
• Eide, Per Kristian; Pripp, Are Hugo; Ringstad, Geir & Valnes, Lars Magnus (2021). Impaired glymphatic function in idiopathic intracranial hypertension. Brain Communications. ISSN 2632-1297. 3:fcab043(2), s. 1–14. doi: 10.1093/braincomms/fcab043. Fulltekst i vitenarkiv
• Mannerak, Mari Aaroe; Lashkarivand, Aslan & Eide, Per Kristian (2021). Trigeminal neuralgia and genetics: A systematic review. Molecular Pain. ISSN 1744-8069. 17, s. 1–22. doi: 10.1177/17448069211016139. Fulltekst i vitenarkiv
• Rostalski, Hannah; Korhonen, Ville; Kuulasmaa, Teemu; Solje, Eino; Krüger, Johanna & Kaivola, Karri [Vis alle 14 forfattere av denne artikkelen] (2021). A Novel Genetic Marker for the C9orf72 Repeat Expansion in the Finnish Population. Journal of Alzheimer's Disease. ISSN 1387-2877. 83(3), s. 1325–1332. doi: 10.3233/JAD-210599. Fulltekst i vitenarkiv
• Masina, Riccardo; Ansaripour, Ali; Beneš, Vladimír; Berhouma, Moncef; Choque-Velasquez, Joham & Eide, Per Kristian [Vis alle 18 forfattere av denne artikkelen] (2021). Surgical treatment of symptomatic pineal cysts without hydrocephalus—meta-analysis of the published literature. Acta Neurochirurgica. ISSN 0001-6268. 164(1), s. 61–77. doi: 10.1007/s00701-021-05054-0. Fulltekst i vitenarkiv
• Eide, Per Kristian & Ringstad, Geir (2021). Cerebrospinal fluid egress to human parasagittal dura and the impact of sleep deprivation. Brain Research. ISSN 0006-8993. 1772, s. 1–8. doi: 10.1016/j.brainres.2021.147669. Fulltekst i vitenarkiv
• Sorteberg, Wilhelm; Sorteberg, Angelika; Jacobsen, Eva Astrid; RØNNING, PÅL ANDRE; Nome, Terje & Eide, Per Kristian (2021). Endovascular versus surgical treatment of cranial dural arteriovenous fistulas: a single-center 8-year experience. Acta Neurochirurgica. ISSN 0001-6268. 164(1), s. 151–161. doi: 10.1007/s00701-021-04950-9. Fulltekst i vitenarkiv
• Eide, Per Kristian (2021). Abnormal intracranial pulse pressure amplitude despite normalized static intracranial pressure in idiopathic intracranial hypertension refractory to conservative medical therapy. Life. ISSN 2075-1729. 11(6), s. 1–10. doi: 10.3390/life11060537. Fulltekst i vitenarkiv
• Eide, Per Kristian; Mariussen, Espen; Uggerud, Hilde Thelle; Pripp, Are Hugo; Lashkarivand, Aslan & Hassel, Bjørnar [Vis alle 8 forfattere av denne artikkelen] (2021). Clinical application of intrathecal gadobutrol for assessment of cerebrospinal fluid tracer clearance to blood. JCI Insight. ISSN 2379-3708. 6(9), s. 1–13. doi: 10.1172/jci.insight.147063. Fulltekst i vitenarkiv
• Eide, Per Kristian; Vinje, Vegard; Pripp, Are Hugo; Mardal, Kent-Andre & Ringstad, Geir (2021). Sleep deprivation impairs molecular clearance from the human brain. Brain. ISSN 0006-8950. 144(3), s. 863–874. doi: 10.1093/brain/awaa443.
• Eide, Per Kristian; Valnes, Lars Magnus; Lindstrøm, Erika Kristina; Mardal, Kent-Andre & Ringstad, Geir (2021). Direction and magnitude of cerebrospinal fluid flow vary substantially across central nervous system diseases. Fluids and Barriers of the CNS. ISSN 2045-8118. 18(1), s. 1–18. doi: 10.1186/s12987-021-00251-6. Fulltekst i vitenarkiv
• Frič, Radek; Langvatn, Erlend Aambø; Due-Tønnessen, Bernt Johan & Eide, Per Kristian (2021). The role of pulsatile and static intracranial pressure measurements in the management of children with craniosynostosis–an institutional experience from 49 patients. Acta Neurochirurgica. ISSN 0001-6268. 163(7), s. 2015–2023. doi: 10.1007/s00701-020-04680-4.
• Khan, Haroon; Naseer, Noman; Yazidi, Anis; Eide, Per Kristian; Hassan, Wajahat & Mirtaheri, Peyman (2021). Analysis of Human Gait Using Hybrid EEG-fNIRS-Based BCI System: A Review. Frontiers in Human Neuroscience. ISSN 1662-5161. 14, s. 1–29. doi: 10.3389/fnhum.2020.613254. Fulltekst i vitenarkiv
• O’Rourke, Michael; Stone, Jonathan; Adji, Audrey; Kim, Mi Ok; Li, Yan & Wang, Ji Guang [Vis alle 9 forfattere av denne artikkelen] (2020). The human systemic and cerebral circulations: Contrasts in structure and function. Artery Research. ISSN 1872-9312. 26(4), s. 197–211. doi: 10.2991/ARTRES.K.200704.001.
• Halvorsen, Merete; Edeklev, Camilla; Fraser-Green, Jorunn; Løvland, Grethe; Vatnehol, Svein Are Sirirud & Gjertsen, Øivind [Vis alle 10 forfattere av denne artikkelen] (2020). Off-label intrathecal use of gadobutrol: safety study and comparison of administration protocols . Neuroradiology. ISSN 0028-3940. 63(1), s. 51–61. doi: 10.1007/s00234-020-02519-4. Fulltekst i vitenarkiv
• Eide, Per Kristian; Pripp, Are Hugo & Ringstad, Geir (2020). Magnetic resonance imaging biomarkers of cerebrospinal fluid tracer dynamicsâin idiopathic normal pressure hydrocephalus. Brain Communications. ISSN 2632-1297. 2(2), s. 1–16. doi: 10.1093/braincomms/fcaa187. Fulltekst i vitenarkiv
• Carare, Roxana O.; Aldea, Roxana; Agarwal, Nivedita; Bacskai, Brian J.; Bechman, Ingo & Boche, Delphine [Vis alle 45 forfattere av denne artikkelen] (2020). Clearance of interstitial fluid (ISF) and CSF (CLIC) group—part of Vascular Professional Interest Area (PIA): Cerebrovascular disease and the failure of elimination of Amyloid-β from the brain and retina with age and Alzheimer's disease-Opportunities for Therapy. Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring. ISSN 2352-8729. 12(1), s. 1–7. doi: 10.1002/dad2.12053. Fulltekst i vitenarkiv
• Sorteberg, Wilhelm; Sorteberg, Angelika; Jacobsen, Eva Astrid; RØNNING, PÅL ANDRE & Eide, Per Kristian (2020). Intracranial Hemorrhage From Dural Arteriovenous Fistulas: Symptoms, Early Rebleed, and Acute Management: A Single-Center 8-Year Experience. Neurosurgery. ISSN 0148-396X. 1(4), s. 1–11. doi: 10.1093/neuopn/okaa019. Fulltekst i vitenarkiv
• Jacobsen, Henrik Holvin; Sandell, Tiril; Jørstad, Øystein Kalsnes; Moe, Morten Carsten; Ringstad, Geir & Eide, Per Kristian (2020). In vivo evidence for impaired glymphatic function in the visual pathway of patients with normal pressure hydrocephalus. Investigative Ophthalmology and Visual Science. ISSN 0146-0404. 61:24(13), s. 1–11. doi: 10.1167/IOVS.61.13.24. Fulltekst i vitenarkiv
• Melin, Erik; Eide, Per Kristian & Ringstad, Geir (2020). In vivo assessment of cerebrospinal fluid efflux to nasal mucosa in humans. Scientific Reports. ISSN 2045-2322. 10(1), s. 1–10. doi: 10.1038/s41598-020-72031-5. Fulltekst i vitenarkiv
• Ringstad, Geir & Eide, Per Kristian (2020). Glymfatisk MR. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 140(1), s. 1–2. doi: 10.4045/tidsskr.19.0651.
• Eide, Per Kristian; Hasan-Olive, Md Mahdi; Hansson, Hans-Arne & Enger, Rune (2020). Increased occurrence of pathological mitochondria in astrocytic perivascular endfoot processes and neurons of idiopathic intracranial hypertension. Journal of Neuroscience Research. ISSN 0360-4012. 99(2), s. 467–480. doi: 10.1002/jnr.24743.
• Evensen, Karen Brastad & Eide, Per Kristian (2020). Mechanisms behind altered pulsatile intracranial pressure in idiopathic normal pressure hydrocephalus: role of vascular pulsatility and systemic hemodynamic variables. Acta Neurochirurgica. ISSN 0001-6268. 162(8), s. 1803–1813. doi: 10.1007/s00701-020-04423-5. Fulltekst i vitenarkiv
• Valnes, Lars Magnus; Mitusch, Sebastian; Ringstad, Geir; Eide, Per Kristian; Funke, Simon Wolfgang & Mardal, Kent-Andre (2020). Apparent diffusion coefficient estimates based on 24 hours tracer movement support glymphatic transport in human cerebral cortex. Scientific Reports. ISSN 2045-2322. 10(1), s. 1–12. doi: 10.1038/s41598-020-66042-5. Fulltekst i vitenarkiv
• Evensen, Karen Brastad & Eide, Per Kristian (2020). Measuring intracranial pressure by invasive, less invasive or non-invasive means: limitations and avenues for improvement. Fluids and Barriers of the CNS. ISSN 2045-8118. 17(34), s. 1–33. doi: 10.1186/s12987-020-00195-3. Fulltekst i vitenarkiv
• Ringstad, Geir & Eide, Per Kristian (2020). Cerebrospinal fluid tracer efflux to parasagittal dura in humans. Nature Communications. ISSN 2041-1723. 11(1), s. 1–9. doi: 10.1038/s41467-019-14195-x. Fulltekst i vitenarkiv
• Frič, Radek & Eide, Per Kristian (2019). Chiari type 1-a malformation or a syndrome? A critical review. Acta Neurochirurgica. ISSN 0001-6268. 162(7), s. 1513–1525. doi: 10.1007/s00701-019-04100-2.
• Eide, Per Kristian & Hansson, Hans-Arne (2019). Blood-brain barrier leakage of blood proteins in idiopathic normal pressure hydrocephalus. Brain Research. ISSN 0006-8993. 1727, s. 1–13. doi: 10.1016/j.brainres.2019.146547. Fulltekst i vitenarkiv
• Lashkarivand, Aslan; Ringstad, Geir & Eide, Per Kristian (2019). Surgery for Brainstem Cavernous Malformations: Association between Preoperative Grade and Postoperative Quality of Life. Operative Neurosurgery. ISSN 2332-4252. 18(6), s. 590–598. doi: 10.1093/ons/opz337.
• Hasan-Olive, Md Mahdi; Enger, Rune; Hansson, Hans-Arne; Nagelhus, Erlend Arnulf & Eide, Per Kristian (2019). Pathological mitochondria in neurons and perivascular astrocytic endfeet of idiopathic normal pressure hydrocephalus patients. Fluids and Barriers of the CNS. ISSN 2045-8118. 16:39, s. 1–16. doi: 10.1186/s12987-019-0160-7. Fulltekst i vitenarkiv
• Edeklev, Camilla; Halvorsen, Merete; Løvland, Grethe; Vatnehol, Svein Are Sirirud; Gjertsen, Øivind & Nedregaard, Bård [Vis alle 9 forfattere av denne artikkelen] (2019). Intrathecal use of gadobutrol for glymphatic MR imaging: Prospective safety study of 100 patients. American Journal of Neuroradiology. ISSN 0195-6108. 40(8), s. 1257–1264. doi: 10.3174/ajnr.A6136.
• Eide, Per Kristian; Valnes, Lars Magnus; Pripp, Are Hugo; Mardal, Kent-Andre & Ringstad, Geir (2019). Delayed clearance of cerebrospinal fluid tracer from choroid plexus in idiopathic normal pressure hydrocephalus. Journal of Cerebral Blood Flow and Metabolism. ISSN 0271-678X. 40(9), s. 1849–1858. doi: 10.1177/0271678X19874790.
• Hasan-Olive, Md Mahdi; Hansson, Hans-Arne; Enger, Rune; Nagelhus, Erlend Arnulf & Eide, Per Kristian (2019). Blood-Brain Barrier Dysfunction in Idiopathic Intracranial Hypertension. Journal of Neuropathology and Experimental Neurology. ISSN 0022-3069. 78(9), s. 808–818. doi: 10.1093/jnen/nlz063.
• Langvatn, Erlend Aambø; Frič, Radek; Due-Tønnessen, Bernt Johan & Eide, Per Kristian (2019). Intracranial volume versus static and pulsatile intracranial pressure values in children with craniosynostosis. Journal of Neurosurgery: Pediatrics. ISSN 1933-0707. 24(1), s. 66–74. doi: 10.3171/2019.2.PEDS18767.
• Jacobsen, Henrik Holvin; Ringstad, Geir; Jørstad, Øystein Kalsnes; Moe, Morten Carsten; Sandell, Tiril & Eide, Per Kristian (2019). The human visual pathway communicates directly with the subarachnoid space. Investigative Ophthalmology and Visual Science. ISSN 0146-0404. 60(7), s. 2773–2780. doi: 10.1167/iovs.19-26997. Fulltekst i vitenarkiv
• Frič, Radek; Ringstad, Geir & Eide, Per Kristian (2019). Chiari-malformasjon type 1 – diagnostikk og behandling. Tidsskrift for Den norske legeforening. ISSN 0029-2001. 139(10), s. 1–8. doi: 10.4045/tidsskr.18.0455.
• Vinje, Vegard; Ringstad, Geir; Lindstrøm, Erika Kristina; Valnes, Lars Magnus; Rognes, Marie Elisabeth & Eide, Per Kristian (2019). Respiratory influence on cerebrospinal fluid flow – a computational study based on long-term intracranial pressure measurements. Scientific Reports. ISSN 2045-2322. 9, s. 1–13. doi: 10.1038/s41598-019-46055-5. Fulltekst i vitenarkiv
• Bendtsen, Lars; Zakrzewska, Joanna M.; Abbott, Jillie; Braschinsky, Mark; Di Stefano, Giulia & Donnet, Anne Michèle [Vis alle 14 forfattere av denne artikkelen] (2019). European Academy of Neurology guideline on trigeminal neuralgia. European Journal of Neurology. ISSN 1351-5101. 26(6), s. 831–849. doi: 10.1111/ene.13950.
• Evensen, Karen Brastad & Eide, Per Kristian (2019). Non-invasive estimation of the intracranial pressure waveform from the central aortic pressure waveform. World Neurosurgery. ISSN 1878-8750. 121, s. 257–258. doi: 10.1016/j.wneu.2018.10.079. Fulltekst i vitenarkiv
• Eide, Per Kristian & Ringstad, Geir (2018). Delayed clearance of cerebrospinal fluid tracer from entorhinal cortex in idiopathic normal pressure hydrocephalus: A glymphatic magnetic resonance imaging study. Journal of Cerebral Blood Flow and Metabolism. ISSN 0271-678X. 39(7), s. 1355–1368. doi: 10.1177/0271678X18760974.
• Korhonen, Ville E.; Helisalmi, Seppo; Jokinen, Aleksi; Jokinen, Ilari; Lehtola, Juha-Matti & Oinas, Minna [Vis alle 24 forfattere av denne artikkelen] (2018). Copy number loss in SFMBT1 is common among Finnish and Norwegian patients with iNPH. Neurology: Genetics. ISSN 2376-7839. 4(6), s. 1–8. doi: 10.1212/NXG.0000000000000291. Fulltekst i vitenarkiv
• Lindstrøm, Erika Kristina; Ringstad, Geir; Sorteberg, Angelika; Sorteberg, Wilhelm; Mardal, Kent-Andre & Eide, Per Kristian (2018). Magnitude and direction of aqueductal cerebrospinal fluid flow: large variations in patients with intracranial aneurysms with or without a previous subarachnoid hemorrhage. Acta Neurochirurgica. ISSN 0001-6268. 161(2), s. 247–256. doi: 10.1007/s00701-018-3730-6. Vis sammendrag

  Background Net cerebrospinal fluid (CSF) flow within the cerebral aqueduct is usually considered to be antegrade, i.e., from the third to the fourth ventricle with volumes ranging between 500 and 600 ml over 24 h. Knowledge of individual CSF flow dynamics, however, is hitherto scarcely investigated. In order to explore individual CSF flow rate and direction, we assessed net aqueductal CSF flow in individuals with intracranial aneurysms with or without a previous subarachnoid hemorrhage (SAH). Methods A prospective observational study was performed utilizing phase-contrast magnetic resonance imaging (PCMRI) to determine the magnitude and direction of aqueductal CSF flow with an in-depth, pixel-by-pixel approach. Estimation of net flow was used to calculate CSF flow volumes over 24 h. PC-MRI provides positive values when flow is retrograde. Results The study included eight patients with intracranial aneurysms. Four were examined within days after their SAH; three were studied in the chronic stage after SAH while one patient had an unruptured intracranial aneurysm. There was a vast variation in magnitude and direction of aqueductal CSF flow between individuals. Net aqueductal CSF flow was retrograde, i.e., directed towards the third ventricle in 5/8 individuals. For the entire patient cohort, the estimated net aqueductal CSF volumetric flow rate (independent of direction) was median 898 ml/24 h (ranges 69 ml/24 h to 12.9 l/ 24 h). One of the two individuals who had a very high estimated net aqueductal CSF volumetric flow rate, 8.7 l/24 h retrograde, later needed a permanent CSF shunt. Conclusions The magnitude and direction of net aqueductal CSF flow vary extensively in patients with intracranial aneurysms. Following SAH, PC-MRI may offer the possibility to perform individualized assessments of the CSF circulation.

• Hasan-Olive, Md Mahdi; Enger, Rune; Hansson, Hans-Arne; Nagelhus, Erlend Arnulf & Eide, Per Kristian (2018). Loss of perivascular aquaporin-4 in idiopathic normal pressure hydrocephalus. Glia. ISSN 0894-1491. 67(1), s. 91–100. doi: 10.1002/glia.23528.
• Evensen, Karen Brastad; Paulat, Klaus; Prieur, Fabrice Jean Gabriel; Holm, Sverre & Eide, Per Kristian (2018). Utility of the Tympanic Membrane Pressure Waveform for Non-invasive Estimation of The Intracranial Pressure Waveform. Scientific Reports. ISSN 2045-2322. 8, s. 1–11. doi: 10.1038/s41598-018-34083-6. Fulltekst i vitenarkiv
• Lindstrøm, Erika Kristina; Ringstad, Geir; Mardal, Kent-Andre & Eide, Per Kristian (2018). Cerebrospinal fluid volumetric net flow rate and direction in idiopathic normal pressure hydrocephalus. NeuroImage: Clinical. ISSN 2213-1582. 20, s. 731–741. doi: 10.1016/j.nicl.2018.09.006. Fulltekst i vitenarkiv
• Eidsvaag, Vigdis Andersen; Hansson, Hans-Arne; Heuser, Kjell; Nagelhus, Erlend Arnulf & Eide, Per Kristian (2018). Cerebral microvascular abnormalities in patients with idiopathic intracranial hypertension. Brain Research. ISSN 0006-8993. 1686, s. 72–82. doi: 10.1016/j.brainres.2018.02.017.
• Eide, Per Kristian; Vatnehol, Svein Are Sirirud; Emblem, Kyrre Eeg & Ringstad, Geir (2018). Magnetic resonance imaging provides evidence of glymphatic drainage from human brain to cervical lymph nodes. Scientific Reports. ISSN 2045-2322. 8(1), s. 1–10. doi: 10.1038/s41598-018-25666-4. Fulltekst i vitenarkiv
• Ringstad, Geir; Valnes, Lars Magnus; Dale, Anders; Pripp, Are Hugo; Vatnehol, Svein Are Sirirud & Emblem, Kyrre Eeg [Vis alle 8 forfattere av denne artikkelen] (2018). Brain-wide glymphatic enhancement and clearance in humans assessed with MRI. Journal of Clinical Investigation. ISSN 0021-9738. 3(13), s. 1–16. doi: 10.1172/jci.insight.121537. Fulltekst i vitenarkiv
• Evensen, Karen Brastad; O'Rourke, Michael; Prieur, Fabrice Jean Gabriel; Holm, Sverre & Eide, Per Kristian (2018). Non-invasive Estimation of the Intracranial Pressure Waveform from the Central Arterial Blood Pressure Waveform in Idiopathic Normal Pressure Hydrocephalus Patients. Scientific Reports. ISSN 2045-2322. 8:4714, s. 1–11. doi: 10.1038/s41598-018-23142-7.
• Lindstrøm, Erika Kristina; Schreiner, Jakob Emil; Ringstad, Geir; Haughton, Victor; Eide, Per Kristian & Mardal, Kent-Andre (2018). Comparison of phase-contrast MR and flow simulations for the study of CSF Dynamics in the cervical spine. The Neuroradiology Journal (NRJ). ISSN 1971-4009. 31(3), s. 292–298. doi: 10.1177/1971400918759812.
• Eide, Per Kristian (2017). The pathophysiology of chronic noncommunicating hydrocephalus: lessons from continuous intracranial pressure monitoring and ventricular infusion testing. Journal of Neurosurgery. ISSN 0022-3085. 129(1), s. 220–233. doi: 10.3171/2017.1.JNS162813.
• Eide, Per Kristian & Hansson, Hans-Arne (2017). Astrogliosis and impaired aquaporin-4 and dystrophin systems in idiopathic normal pressure hydrocephalus. Neuropathology and Applied Neurobiology. ISSN 0305-1846. 44(5), s. 474–490. doi: 10.1111/nan.12420.
• Eidsvaag, Vigdis Andersen; Hansson, Hans-Arne; Heuser, Kjell; Nagelhus, Erlend Arnulf & Eide, Per Kristian (2017). Brain Capillary Ultrastructure in Idiopathic Normal Pressure Hydrocephalus: Relationship With Static and Pulsatile Intracranial Pressure. Journal of Neuropathology and Experimental Neurology. ISSN 0022-3069. 76(12), s. 1034–1045. doi: 10.1093/jnen/nlx091.
• Ringstad, Geir; Lindstrøm, Erika Kristina; Vatnehol, Svein Are Sirirud; Mardal, Kent-Andre; Emblem, Kyrre Eeg & Eide, Per Kristian (2017). Non-invasive assessment of pulsatile intracranial pressure with phase-contrast magnetic resonance imaging. PLOS ONE. ISSN 1932-6203. 12(11), s. 1–17. doi: 10.1371/journal.pone.0188896. Fulltekst i vitenarkiv
• Meling, Torstein Ragnar; Romundstad, Luis Georg; Niemi, Geir; Narum, Jon; Eide, Per Kristian & Sorteberg, Angelika [Vis alle 7 forfattere av denne artikkelen] (2017). Adenosine-assisted clipping of intracranial aneurysms. Neurosurgical review. ISSN 0344-5607. 41(2), s. 585–592. doi: 10.1007/s10143-017-0896-y.
• Frič, Radek & Eide, Per Kristian (2017). Comparative observational study on the clinical presentation, intracranial volume measurements, and intracranial pressure scores in patients with either Chiari malformation Type I or idiopathic intracranial hypertension. Journal of Neurosurgery. ISSN 0022-3085. 126(4), s. 1312–1322. doi: 10.3171/2016.4.JNS152862.
• Ringstad, Geir; Vatnehol, Svein Are Sirirud & Eide, Per Kristian (2017). Glymphatic MRI in idiopathic normal pressure hydrocephalus. Brain. ISSN 0006-8950. 140(10), s. 2691–2705. doi: 10.1093/brain/awx191. Fulltekst i vitenarkiv

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• Eide, Per Kristian & Ringstad, Geir (2018). Cerebrospinal Fluid Flow and Glymphatic Function in Idiopathic Normal Pressure Hydrocephalus (book chapter) p.71-84 in: Cerebrospinal Fluid Disorders - Lifelong Implications (Springer Nature, 2018). Springer Nature. ISBN 978-3-319-97928-1. 14 s.

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• Melin, Erik; Eide, Per Kristian & Ringstad, Geir (2023). Author Correction: In vivo assessment of cerebrospinal fluid efflux to nasal mucosa in humans (Scientific Reports, (2020), 10, 1, (14974), 10.1038/s41598-020-72031-5). Scientific Reports. ISSN 2045-2322. 13(1). doi: 10.1038/s41598-023-43372-8.
• Ringstad, Geir & Eide, Per Kristian (2023). The pitfalls of interpreting hyperintense FLAIR signal as lymph outside the human brain. Nature Communications. ISSN 2041-1723. 14(1). doi: 10.1038/s41467-023-40508-2.
• Thavarajasingam, Santhosh G.; El-Khatib, Mahmoud; Vemulapalli, Kalyan V.; Ramsay, Daniele S. C.; Ponniah, Hariharan Subbiah & Fernandes, Rafael T. [Vis alle 8 forfattere av denne artikkelen] (2023). Inadequacies in iNPH diagnosis: envisioning a paradigm shift towards integrated, multi-modal testing, and consensus-driven research for improved patient outcomes. Acta Neurochirurgica. ISSN 0001-6268. doi: 10.1007/s00701-023-05754-9.
• Hovd, Markus Herberg; Mariussen, Espen; Uggerud, Hilde Thelle; Lashkarivand, Aslan; Christensen, Hege & Ringstad, Geir [Vis alle 7 forfattere av denne artikkelen] (2023). CSF to blood clearance differs substantially across individuals and patients with CSF disorders. Fluids and Barriers of the CNS. ISSN 2045-8118. 19. doi: 10.1186/s12987-022-00397-x.
• Lashkarivand, Aslan & Eide, Per Kristian (2022). The first report on brain sagging dementia caused by a cranial leak: A case report. Frontiers in Neurology. ISSN 1664-2295. 13, s. 1–6. doi: 10.3389/fneur.2022.1006060. Fulltekst i vitenarkiv
• Sorteberg, Wilhelm; Sorteberg, Angelika; Jacobsen, Eva Astrid; Rønning, Pål Andre; Nome, Terje & Eide, Per Kristian (2022). Microsurgery as first-line treatment in acute hemorrhagic cranial dural arteriovenous fistulas (dAVFs) and ruptured intracranial aneurysms—anachronism or duty? Acta Neurochirurgica. ISSN 0001-6268. 164, s. 1303–1305. doi: 10.1007/s00701-022-05197-8.
• Ringstad, Geir & Eide, Per Kristian (2021). Safety of Intrathecal Gadolinium-based Contrast Agents and Benefit versus Risk . Radiology. ISSN 0033-8419. 229(1), s. E223–E224. doi: 10.1148/radiol.2021203351.
• Eide, Per Kristian & Sorteberg, Wilhelm (2021). Invasive tests for predicting shunt response in idiopathic normal pressure hydrocephalus: the risk aspect. Acta Neurochirurgica. ISSN 0001-6268. s. 1–2. doi: 10.1007/s00701-021-05050-4.
• Eide, Per Kristian & Ringstad, Geir (2019). Intracranial Pulsatility, Cerebrospinal Fluid Flow, and Glymphatic Function in Idiopathic Normal Pressure Hydrocephalus . I Limbrick Jr., David D. & Reonard, Jeffrey R. (Red.), Cerebrospinal Fluid Disorders Lifelong Implications. Springer Nature. ISSN 978-3-319-97927-4. s. 71–84. doi: https:/doi.org/10.1007/978-3-319-97928-1.
• Eide, Per Kristian & Ringstad, Geir (2019). In Vivo Imaging of Molecular Clearance From Human Entorhinal Cortex: A Possible Method for Preclinical Testing of Dementia. Gerontology and geriatric medicine. ISSN 2333-7214. 5, s. 1–4. doi: 10.1177/2333721419889739. Fulltekst i vitenarkiv
• Eide, Per Kristian; Sorteberg, Angelika; Sorteberg, Wilhelm; Lindstrøm, Erika Kristina; Mardal, Kent-Andre & Ringstad, Geir (2018). "Bucket" cerebrospinal fluid bulk flow: when the terrain disagrees with the map. Acta Neurochirurgica. ISSN 0001-6268. 161(2), s. 259–261. doi: 10.1007/s00701-018-3775-6.

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