1
|
Tu Y, Song R, Xiong F, Fu X. Decreased DTI-ALPS index in delirium: a preliminary MRI study. Neuroradiology 2024:10.1007/s00234-024-03415-x. [PMID: 38980344 DOI: 10.1007/s00234-024-03415-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 06/25/2024] [Indexed: 07/10/2024]
Abstract
PURPOSE Delirium is linked to brain abnormalities, yet the role of the glymphatic system is not well understood. This study aims to examine alterations in brain physiology in delirium by using diffusion-tensor imaging (DTI) to assess water diffusion along the perivascular space (ALPS) and to explore its correlation with clinical symptoms. METHODS We examined 15 patients with delirium and 15 healthy controls, measuring water diffusion metrics along the x-, y-, and z-axes in both projection and association fibers to determine the DTI-ALPS index. We used a general linear model, adjusted for age and sex, to compare the DTI-ALPS index between groups. We also investigated the relationship between the DTI-ALPS index and clinical symptoms using partial correlations. RESULTS Patients with delirium exhibited significantly lower DTI-ALPS indices compared to healthy controls (1.25 ± 0.15 vs. 1.38 ± 0.10, t = 2.903, p = 0.007; 1.27 ± 0.16 vs. 1.39 ± 0.08, 1.22 ± 0.16 vs. 1.37 ± 0.14, t = 2.617, p = 0.014; t = 2.719, p = 0.011; respectively). However, there was no significant correlation between the DTI-ALPS index and clinical symptoms. CONCLUSION Our findings indicate a decreased DTI-ALPS index in patients with delirium, suggesting potential alterations in brain physiology that may contribute to the pathophysiology of delirium. This study provides new insights into the mechanisms underlying delirium.
Collapse
Affiliation(s)
- Ye Tu
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Renjie Song
- Department of Emergency, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Fei Xiong
- Department of Radiology, General Hospital of Central Theater Command, Wuhan, China
| | - Xiaoyun Fu
- Department of Critical Care Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, China.
| |
Collapse
|
2
|
Taoka T, Ito R, Nakamichi R, Nakane T, Kawai H, Naganawa S. Diffusion Tensor Image Analysis ALong the Perivascular Space (DTI-ALPS): Revisiting the Meaning and Significance of the Method. Magn Reson Med Sci 2024; 23:268-290. [PMID: 38569866 PMCID: PMC11234944 DOI: 10.2463/mrms.rev.2023-0175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024] Open
Abstract
More than 5 years have passed since the Diffusion Tensor Image Analysis ALong the Perivascular Space (DTI-ALPS) method was proposed with the intention of evaluating the glymphatic system. This method is handy due to its noninvasiveness, provision of a simple index in a straightforward formula, and the possibility of retrospective analysis. Therefore, the ALPS method was adopted to evaluate the glymphatic system for many disorders in many studies. The purpose of this review is to look back and discuss the ALPS method at this moment.The ALPS-index was found to be an indicator of a number of conditions related to the glymphatic system. Thus, although this was expected in the original report, the results of the ALPS method are often interpreted as uniquely corresponding to the function of the glymphatic system. However, a number of subsequent studies have pointed out the problems on the data interpretation. As they rightly point out, a higher ALPS-index indicates predominant Brownian motion of water molecules in the radial direction at the lateral ventricular body level, no more and no less. Fortunately, the term "ALPS-index" has become common and is now known as a common term by many researchers. Therefore, the ALPS-index should simply be expressed as high or low, and whether it reflects a glymphatic system is better to be discussed carefully. In other words, when a decreased ALPS-index is observed, it should be expressed as "decreased ALPS-index" and not directly as "glymphatic dysfunction". Recently, various methods have been proposed to evaluate the glymphatic system. It has become clear that these methods also do not seem to reflect the entirety of the extremely complex glymphatic system. This means that it would be desirable to use various methods in combination to evaluate the glymphatic system in a comprehensive manner.
Collapse
Affiliation(s)
- Toshiaki Taoka
- Department of Innovative Biomedical Visualization (iBMV), Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Rintaro Ito
- Department of Innovative Biomedical Visualization (iBMV), Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Rei Nakamichi
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Toshiki Nakane
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| | - Hisashi Kawai
- Department of Radiology, Aichi Medical University, Nagakute, Aichi, Japan
| | - Shinji Naganawa
- Department of Radiology, Nagoya University, Nagoya, Aichi, Japan
| |
Collapse
|
3
|
Pang H, Wang J, Yu Z, Yu H, Li X, Bu S, Zhao M, Jiang Y, Liu Y, Fan G. Glymphatic function from diffusion-tensor MRI to predict conversion from mild cognitive impairment to dementia in Parkinson's disease. J Neurol 2024:10.1007/s00415-024-12525-8. [PMID: 38913186 DOI: 10.1007/s00415-024-12525-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 06/10/2024] [Accepted: 06/15/2024] [Indexed: 06/25/2024]
Abstract
BACKGROUND Although brain glymphatic dysfunction is a contributing factor to the cognitive deficits in Parkinson's disease (PD), its role in the longitudinal progression of cognitive dysfunction remains unknown. OBJECTIVE To investigate the glymphatic function in PD with mild cognitive impairment (MCI) that progresses to dementia (PDD) and to determine its predictive value in identifying individuals at high risk for developing dementia. METHODS We included 64 patients with PD meeting criteria for MCI and categorized them as either progressed to PDD (converters) (n = 29) or did not progress to PDD (nonconverters) (n = 35), depending on whether they developed dementia during follow-up. Meanwhile, 35 age- and gender-matched healthy controls (HC) were included. Bilateral diffusion-tensor imaging analysis along the perivascular space (DTI-ALPS) indices and enlarged perivascular spaces (EPVS) volume fraction in bilateral centrum semiovale, basal ganglia (BG), and midbrain were compared among the three groups. Correlations among the DTI-ALPS index and EPVS, as well as cognitive performance were analyzed. Additionally, we investigated the mediation effect of EPVS on DTI-ALPS and cognitive function. RESULTS PDD converters had lower cognitive composites scores in the executive domains than did nonconverters (P < 0.001). Besides, PDD converters had a significantly lower DTI-ALPS index in the left hemisphere (P < 0.001) and a larger volume fraction of BG-PVS (P = 0.03) compared to HC and PDD nonconverters. Lower DTI-ALPS index and increased BG-PVS volume fraction were associated with worse performance in the global cognitive performance and executive function. However, there was no significant mediating effect. Receiver operating characteristic analysis revealed that the DTI-ALPS could effectively identify PDD converters with an area under the curve (AUC) of 0.850. CONCLUSION The reduction of glymphatic activity, measured by the DTI-ALPS, could potentially be used as a non-invasive indicator in forecasting high risk of dementia conversion before the onset of dementia in PD patients.
Collapse
Affiliation(s)
- Huize Pang
- Department of Radiology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Juzhou Wang
- Department of Radiology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Ziyang Yu
- School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Hongmei Yu
- Department of Neurology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Xiaolu Li
- Department of Radiology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Shuting Bu
- Department of Radiology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Mengwan Zhao
- Department of Radiology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Yueluan Jiang
- MR Research Collaboration, Siemens Healthineers, Beijing, China
| | - Yu Liu
- Department of Radiology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China
| | - Guoguang Fan
- Department of Radiology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China.
| |
Collapse
|
4
|
Sugai Y, Hiraka T, Shibata A, Taketa A, Tanae T, Moriya Y, Komatsu M, Iseki C, Ohta Y, Kanoto M. The time-course augmentation of perivascular space enlargement in the basal ganglia among a community-dwelling elder population. Jpn J Radiol 2024:10.1007/s11604-024-01595-3. [PMID: 38896331 DOI: 10.1007/s11604-024-01595-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 05/15/2024] [Indexed: 06/21/2024]
Abstract
PURPOSE We examined whether time-course augmentation of perivascular space enlargement in the basal ganglia (BG-PVS) reflected cerebral small vessel disease (CSVD) severity by considering white matter hyperintensity lesion (WMHL) as an indicator for CSVD. MATERIALS AND METHODS This study population included 416 older participants from a community-based cohort. They participated in magnetic resonance imaging (MRI) studies more than once during the study period. The grades for BG-PVS and WMHL were evaluated by visual rating scales; BG-PVS time-course augmentation in 4-9 years was also evaluated. At baseline, the participants were asked about their smoking and drinking history, and medical history. They also underwent a blood examination and their office blood pressure (BP) examination. In addition, 24-h ambulatory BP monitoring was also performed within the study period. RESULTS Of the 416 participants, 48 participants (11.5%) had BG-PVS time-course augmentation. The participants with BG-PVS augmentation had significantly lower LDL levels, hyper-nighttime BP, and lower nighttime BP fall in univariate analysis (p = 0.03, p = 0.03, p = 0.003, respectively). In multivariate analysis, lower nighttime BP fall and male sex showed significance (p = 0.02, 0.03, respectively). Additionally, BG-PVS time-course augmentation was significantly associated with subsequent WMHL severity in univariate analysis (p < 0.001), which remained significant in multivariate analysis adjusted by imaging and demographic factors (p = 0.03). In multivariate analysis, additionally adjusted by the clinical factors, the significance disappeared (p = 0.07). CONCLUSION This study revealed that the lower nighttime BP fall in ambulatory blood pressure monitoring was a factor significantly associated with BG-PVS augmentation. Moreover, the BG-PVS time-course augmentation would be a notable finding that was associated with the subsequent WMHL.
Collapse
Affiliation(s)
- Yasuhiro Sugai
- Division of Diagnostic Radiology, Department of Radiology, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan.
| | - Toshitada Hiraka
- Division of Diagnostic Radiology, Department of Radiology, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan
| | - Akiko Shibata
- Division of Diagnostic Radiology, Department of Radiology, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan
| | - Ayato Taketa
- Division of Diagnostic Radiology, Department of Radiology, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan
| | - Taiyo Tanae
- Division of Diagnostic Radiology, Department of Radiology, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan
| | - Yosuke Moriya
- Division of Diagnostic Radiology, Department of Radiology, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan
| | - Masanori Komatsu
- Division of Diagnostic Radiology, Department of Radiology, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan
| | - Chifumi Iseki
- Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan
- Division of Neurology and Clinical Neuroscience, Department of Internal Medicine III, Faculty of Medicine, Yamagata University, Yamagata, Japan
| | - Yasuyuki Ohta
- Division of Neurology and Clinical Neuroscience, Department of Internal Medicine III, Faculty of Medicine, Yamagata University, Yamagata, Japan
| | - Masafumi Kanoto
- Division of Diagnostic Radiology, Department of Radiology, Faculty of Medicine, Yamagata University, 2-2-2 Iida-Nishi, Yamagata, 990-9585, Japan
| |
Collapse
|
5
|
Villacis G, Schmidt A, Rudolf JC, Schwenke H, Küchler J, Schramm P, Ulloa P. Evaluating the glymphatic system via magnetic resonance diffusion tensor imaging along the perivascular spaces in brain tumor patients. Jpn J Radiol 2024:10.1007/s11604-024-01602-7. [PMID: 38819694 DOI: 10.1007/s11604-024-01602-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 05/23/2024] [Indexed: 06/01/2024]
Abstract
PURPOSE To investigate glymphatic system function in patients with brain tumors, including both primary and secondary tumors, using diffusion tensor imaging along perivascular spaces (DTI-ALPS). METHODS We retrospectively analyzed the MR DTI of 24 patients with unilateral brain tumors and compared them with age and sex-matched controls. We compared the DTI-ALPS index of the ipsi- and contralateral brain hemispheres. The region of interest was placed in the periventricular vessels adjacent to the lateral ventricles. Differences between sex, age, and kind of tumor (primary or brain metastasis) were evaluated. Correlations between DTI-ALPS index and age and the tumor's apparent diffusion coefficient (ADC) were also investigated. RESULTS The DTI-ALPS index was significantly lower (p < 0.05) in the tumor-affected hemisphere (mean = 1.26 ± 0.24) than contralateral (mean = 1.43 ± 0.28). A comparison with healthy controls revealed no significant difference on the matched ipsilateral side. However, the DTI-ALPS index of the contralateral side of the patients was larger than the HC. Additionally, no statistically significant differences were found when analyzing the DTI-ALPS index vs. age, sex, and tumor entity. Additionally, we did not find a correlation between the DTI-ALPS index and patient age or tumor ADC. CONCLUSION The decreased DTI-ALPS index in the tumor-affected hemisphere may be related to impaired glymphatic system function. However, cancer is often a systemic disease; thus, the DTI-ALPS index from the contralateral brain hemisphere may not generally be considered as a normal control. Nonetheless, the DTI-ALPS index does not only reflect diffusion in the perivascular spaces but it can also be influenced by factors such as axonal degeneration. Therefore, it does not directly reflect brain waste clearance and changes in the index should be interpreted carefully.
Collapse
Affiliation(s)
- Gabriela Villacis
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Aileen Schmidt
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Justus C Rudolf
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Hannes Schwenke
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Jan Küchler
- Department of Neurosurgery, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Peter Schramm
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany
| | - Patricia Ulloa
- Department of Neuroradiology, University Hospital Schleswig-Holstein (UKSH), Luebeck, Germany.
| |
Collapse
|
6
|
Yu S, Jiang H, Yu L, Liu T, Yang C, Cao J, Song Q, Miao Y, Wang W. DTI-ALPS index decreased in patients with Type 2 Diabetes Mellitus. Front Neurosci 2024; 18:1383780. [PMID: 38841097 PMCID: PMC11150564 DOI: 10.3389/fnins.2024.1383780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 05/03/2024] [Indexed: 06/07/2024] Open
Abstract
Backgrounds Type 2 Diabetes Mellitus (T2DM) has become a significant global public health issue, characterized by a rising prevalence and associated deficits across multiple organ systems. Our study aims to utilize the DTI-ALPS technique to assess the change of ALPS index in T2DM patients, and to explore whether such changes are correlated with cognition level and diffusion parameters. Methods The study involved 41 patients with T2DM (mean age, 60.49 ± 8.88 years) and 27 healthy controls (mean age, 58.00 ± 7.63 years). All subjects underwent MRI examination, cognitive assessment, and laboratory tests. Tract-based spatial statistics (TBSS) was used to evaluate white matter changes. GLM was performed to check the DTI-ALPS index difference between T2DM and HC groups. Spearman correlation analysis and partial correlation analysis were used to analyze the correlation between the DTI-ALPS index and diffusion properties & cognitive scores. Results The results show that the ALPS index was lower in T2DM patients. MoCA score was significantly correlated with the ALPS index. Patients with T2DM had a significant increase in both mean diffusivity (MD) and radial diffusivity (RD) and decrease in fractional anisotropy (FA) compared to the HC group. Conclusion The results suggest that the ALPS index is decreased in T2DM patients and associates with cognitive level.
Collapse
Affiliation(s)
- Shuncheng Yu
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Hongjun Jiang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Langxuan Yu
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Tieli Liu
- College of Medical Imaging, Dalian Medical University, Dalian, Liaoning, China
| | - Chun Yang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Jiajun Cao
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Qingwei Song
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Yanwei Miao
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Weiwei Wang
- Department of Radiology, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| |
Collapse
|
7
|
Zhou L, Yang W, Liu Y, Zheng Y, Ge X, Ai K, Liu G, Zhang J. Moderating effect of education on glymphatic function and cognitive performance in mild cognitive impairment. Front Aging Neurosci 2024; 16:1399943. [PMID: 38756534 PMCID: PMC11096465 DOI: 10.3389/fnagi.2024.1399943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 04/23/2024] [Indexed: 05/18/2024] Open
Abstract
Objective This research aims to investigate putative mechanisms between glymphatic activity and cognition in mild cognitive impairment (MCI) and analyzes whether the relationship between cognitive reserve (CR) and cognition was mediated by glymphatic activity. Methods 54 MCI patients and 31 NCs were enrolled to evaluate the bilateral diffusivity along the perivascular spaces and to acquire an index for diffusivity along the perivascular space (ALPS-index) on diffusion tensor imaging (DTI). The year of education was used as a proxy for CR. The ALPS-index was compared between two groups and correlation analyses among the ALPS-index, cognitive function, and CR were conducted. Mediation analyses were applied to investigate the correlations among CR, glymphatic activity and cognition. Results MCI group had a significantly lower right ALPS-index and whole brain ALPS-index, but higher bilateral diffusivity along the y-axis in projection fiber area (Dyproj) than NCs. In MCI group, the left Dyproj was negatively related to cognitive test scores and CR, the whole brain ALPS-index was positively correlated with cognitive test scores and CR. Mediation analysis demonstrated that glymphatic activity partially mediated the correlations between CR and cognitive function. Conclusion MCI exhibited decreased glymphatic activity compared to NCs. CR has a protective effect against cognitive decline in MCI, and this effect may be partially mediated by changes in glymphatic activity.
Collapse
Affiliation(s)
- Liang Zhou
- Department of Magnetic Resonance, The Second Hospital of Lanzhou University, Lanzhou, China
- Second Clinical Medical School, Lanzhou University, Lanzhou, China
| | - Wenxia Yang
- Department of Magnetic Resonance, The Second Hospital of Lanzhou University, Lanzhou, China
- Second Clinical Medical School, Lanzhou University, Lanzhou, China
| | - Yang Liu
- Department of Magnetic Resonance, The Second Hospital of Lanzhou University, Lanzhou, China
- Second Clinical Medical School, Lanzhou University, Lanzhou, China
| | - Yu Zheng
- Department of Magnetic Resonance, The Second Hospital of Lanzhou University, Lanzhou, China
- Second Clinical Medical School, Lanzhou University, Lanzhou, China
| | - Xin Ge
- Department of Magnetic Resonance, The Second Hospital of Lanzhou University, Lanzhou, China
- Second Clinical Medical School, Lanzhou University, Lanzhou, China
| | - Kai Ai
- Philips Healthcare, Xi’an, China
| | - Guangyao Liu
- Department of Magnetic Resonance, The Second Hospital of Lanzhou University, Lanzhou, China
- Gansu Province Clinical Research Center for Functional and Molecular Imaging, Lanzhou, China
| | - Jing Zhang
- Department of Magnetic Resonance, The Second Hospital of Lanzhou University, Lanzhou, China
- Gansu Province Clinical Research Center for Functional and Molecular Imaging, Lanzhou, China
| |
Collapse
|
8
|
Ringstad G. Glymphatic imaging: a critical look at the DTI-ALPS index. Neuroradiology 2024; 66:157-160. [PMID: 38197950 DOI: 10.1007/s00234-023-03270-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 12/14/2023] [Indexed: 01/11/2024]
Affiliation(s)
- Geir Ringstad
- Department of Radiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
- Department of Geriatrics and Internal Medicine, Sorlandet Hospital, Arendal, Norway.
| |
Collapse
|