An Eulerian formulation for the computational modeling of phase-contrast MRI.

PURPOSE: Computational simulation of phase-contrast MRI (PC-MRI) is an attractive way to physically interpret properties and errors in MRI-reconstructed flow velocity fields. Recent studies have developed PC-MRI simulators that solve the Bloch equation, with the magnetization transport being modeled using a Lagrangian approach. Because this method expresses the magnetization as spatial distribution of particles, influences of particle densities and their spatial uniformities on numerical accuracy are well known. This study developed an alternative method for PC-MRI modeling using an Eulerian approach in which the magnetization is expressed as a spatially smooth continuous function. METHODS: The magnetization motion was described using the Bloch equation with an advection term and computed on a fixed grid using a finite difference method, and k-space sampling was implemented using the spoiled gradient echo sequence. PC-MRI scans of a fully developed flow in straight and stenosed cylinders were acquired to provide numerical examples. RESULTS: Reconstructed flow in a straight cylinder showed excellent agreement with input velocity profiles and mean errors were less than 0.5% of the maximum velocity. Numerical cases of flow in a stenosed cylinder successfully demonstrated the velocity profiles, with displacement artifacts being dependent on scan parameters and intravoxel dephasing due to flow disturbances. These results were in good agreement with those obtained using the Lagrangian approach with a sufficient particle density. CONCLUSION: The feasibility of the Eulerian approach to PC-MRI modeling was successfully demonstrated.

Emerging drugs for the treatment of hepatic fibrosis on nonalcoholic steatohepatitis.

INTRODUCTION: Approved drug therapies for nonalcoholic steatohepatitis (NASH) are lacking, for which various agents are currently being tested in clinical trials. Effective drugs for liver fibrosis, the factor most associated with prognosis in NASH, are important. AREAS COVERED: This study reviewed the treatment of NASH with a focus on the effects of existing drugs and new drugs on liver fibrosis. EXPERT OPINION: Considering the complex pathophysiology of fibrosis in NASH, drug therapy may target multiple pathways. The method of assessing fibrosis is important when considering treatment for liver fibrosis in NASH. The Food and Drug Administration considers an important fibrosis endpoint to be histological improvement in at least one fibrosis stage while preventing worsening of fatty hepatitis. To obtain approval as a drug for NASH, efficacy needs to be demonstrated on endpoints such as liver-related events and myocardial infarction. Among the current therapeutic agents for NASH, thiazolidinedione, sodium-glucose co-transporter 2, and selective peroxisome proliferator-activated receptors α modulator have been reported to be effective against fibrosis, although further evidence is required. The effects of pan-peroxisome proliferator-activated receptors, obeticholic acid, and fibroblast growth factor-21 analogs on liver fibrosis in the development stage therapeutics for NASH are of particular interest.

Computational modeling of multiscale collateral blood supply in a whole-brain-scale arterial network.

The cerebral arterial network covering the brain cortex has multiscale anastomosis structures with sparse intermediate anastomoses (O[102] µm in diameter) and dense pial networks (O[101] µm in diameter). Recent studies indicate that collateral blood supply by cerebral arterial anastomoses has an essential role in the prognosis of acute ischemic stroke caused by large vessel occlusion. However, the physiological importance of these multiscale morphological properties-and especially of intermediate anastomoses-is poorly understood because of innate structural complexities. In this study, a computational model of multiscale anastomoses in whole-brain-scale cerebral arterial networks was developed and used to evaluate collateral blood supply by anastomoses during middle cerebral artery occlusion. Morphologically validated cerebral arterial networks were constructed by combining medical imaging data and mathematical modeling. Sparse intermediate anastomoses were assigned between adjacent main arterial branches; the pial arterial network was modeled as a dense network structure. Blood flow distributions in the arterial network during middle cerebral artery occlusion simulations were computed. Collateral blood supply by intermediate anastomoses increased sharply with increasing numbers of anastomoses and provided one-order-higher flow recoveries to the occluded region (15%-30%) compared with simulations using a pial network only, even with a small number of intermediate anastomoses (≤10). These findings demonstrate the importance of sparse intermediate anastomoses, which are generally considered redundant structures in cerebral infarction, and provide insights into the physiological significance of the multiscale properties of arterial anastomoses.

Glycation promotes pulp calcification in Type 2 diabetes rat model.

OBJECTIVES: Intrapulpal calcifications can occur in the dental pulp of patients with diabetes. We focused on the association between ectopic calcifications in the dental pulp and advanced glycation end products (AGEs) in Spontaneously Diabetic Torii (SDT)-fatty rats, an obese type 2 diabetic rat model, to determine the mechanism of calcification with pulp stone in the dental pulp. MATERIALS AND METHODS: Pathologic calcification in the dental pulp of SDT-fatty rats was observed using electron microscopy and immunohistochemical analysis. Moreover, mechanical analysis of periapical region of molar tooth against occlusal force was performed. RESULTS: In SDT-fatty rats, pathogenic pulpal calcifications occurred during blood glucose elevation after 6 weeks, and granular calcification was observed in the dental pulp after 11 weeks. Pentosidine, a major AGE, and the receptor for AGEs were strongly expressed in the dental pulp of SDT-fatty rats. S100A8, TNF-α, and IL-6 also showed positive response in the dental pulp of the SDT-fatty rat, which indicated pulpal inflammation. Blood flow disorder and hypoxic dental pulp cells were also observed. In silico simulation, strain from occlusal force concentrates on the root apex. CONCLUSIONS: Glycation makes blood vessels fragile, and occlusal forces damage the vessels mechanically. These are factors for intrapulpal calcification of diabetes.

Influence of caregiver understanding of their capability to perform activities of daily living, disease comprehension, and attitudes on occupational low back pain: a cross-sectional study.

[Purpose] The aim in this study was to evaluate the impact of caregiver understanding of their ability to perform activities of daily living (ADLs), movement abilities, diseases, and attitudes on the prevalence of occupational low back pain. [Participants and Methods] A cross-sectional survey was conducted of caregivers of older adults living in residential care facilities. Of the 150 questionnaires distributed, 71 were valid. The survey collected data on demographics, low back pain status using a numerical rating scale, and familiarity with ten ADLs and five diseases (stroke, rheumatoid arthritis, fractures, Parkinson's disease, and dementia). [Results] In this study, 52% of the participants reported lower back pain. Significant factors included an understanding of repositioning in ADLs, familiarity with stroke and rheumatoid arthritis, and attitudes toward using patients' residual functions. Participants with limited knowledge of repositioning and stroke, a better understanding of rheumatoid arthritis, and those who did not consider residual function were more prone to lower back pain. [Conclusion] Our findings highlight the importance of enhancing caregiver education on ADL movements and disease specifics, particularly stroke and rheumatoid arthritis, and promoting the use of patients' residual capabilities. Improved training and information sharing among caregivers may reduce the risk of occupational low back pain.

Analysis of fall risk factors and environmental hazards for older adults in Japan: assessing fall situations and locations.

[Purpose] This study aimed to examine falls among older adults in Japanese households and determine the risk associated with each fall location. [Participants and Methods] This study included 99 participants (249 fall events) who received daycare rehabilitation at a nursing care facility. Data on fall circumstances were collected from the medical records and accident reports. The analyzed variables included age, medical status, level of care required, fall history, location, and mode of transportation during the falls. [Results] Falls occurred most commonly in bedrooms. Falls at an entrance were associated with no assistive device (OR: 1.76, 95% CI: 1.06-1.80) and 1 history of falls (OR: 1.22, 95% CI: 1.03-3.10). Risk factors for falls in bedrooms included Parkinson's disease (OR: 1.83, 95% CI: 1.11-1.87), orthopedic disease (OR: 1.11, 95% CI: 1.15-3.43), and cane walking (OR: 1.08, 95% CI: 1.33-4.13). Falls in a hallway were associated with no assistive device (OR: 1.75, 95% CI: 1.15-1.91). [Conclusion] Bedrooms and hallways in Japanese households were identified as locations with a high risk of falls. The unique architectural and cultural features of Japanese homes may contribute to this risk. Rehabilitation programs should consider individual fall histories, medical conditions, and differences in mobility.

Predicting the occurrence of in-season groin pain in male high school soccer players: a cohort study.

[Purpose] This study investigated whether pre-season HAGOS (Japanese Copenhagen Hip and Groin Outcome Scores) and eccentric muscle strength of the hip muscles predict in-season groin pain incidences in high school soccer players. [Participants and Methods] This study had a cohort design. The participants were male high school players under 18 years playing in the Japan Soccer League, which is an elite-level soccer league of that age category in Japan. The HAGOS and the strength of hip abductor and adductor muscles in eccentric contraction were measured before the season, and hip and groin pain incidences were recorded during the season. Multiple logistic regression analysis was performed to investigate the factors derived from the pre-season HAGOS and hip muscle strength tests, presumably pertaining to the development of in-season groin pain. [Results] The eccentric adductor muscle strength of the dominant leg and the HAGOS were selected as factors associated with groin pain during the season. [Conclusion] Low pre-season HAGOS and weak dominant-leg eccentric adductor muscle strength were suggested as factors to predict in-season groin pain occurrence in male high school soccer players.

Aging-related volume changes in the brain and cerebrospinal fluid using artificial intelligence-automated segmentation.

OBJECTIVES: To verify the reliability of the volumes automatically segmented using a new artificial intelligence (AI)-based application and evaluate changes in the brain and CSF volume with healthy aging. METHODS: The intracranial spaces were automatically segmented in the 21 brain subregions and 5 CSF subregions using the AI-based application on the 3D T1-weighted images in healthy volunteers aged > 20 years. Additionally, the automatically segmented volumes of the total ventricles and subarachnoid spaces were compared with the manually segmented volumes of those extracted from 3D T2-weighted images using the intra-class correlation and Bland-Altman analysis. RESULTS: In this study, 133 healthy volunteers aged 21-92 years were included. The mean intra-class correlations between the automatically and manually segmented volumes of the total ventricles and subarachnoid spaces were 0.986 and 0.882, respectively. The increase in the CSF volume was estimated to be approximately 30 mL (2%) per decade from 265 mL (18.7%) in the 20s to 488 mL (33.7%) in ages above 80 years; however, the increase in the volume of total ventricles was approximately 20 mL (< 2%) until the 60s and increased in ages above 60 years. CONCLUSIONS: This study confirmed the reliability of the CSF volumes using the AI-based auto-segmentation application. The intracranial CSF volume increased linearly because of the brain volume reduction with aging; however, the ventricular volume did not change until the age of 60 years and above and then gradually increased. This finding could help elucidate the pathogenesis of chronic hydrocephalus in adults. KEY POINTS: • The brain and CSF spaces were automatically segmented using an artificial intelligence-based application. • The total subarachnoid spaces increased linearly with aging, whereas the total ventricle volume was around 20 mL (< 2%) until the 60s and increased in ages above 60 years. • The cortical gray matter gradually decreases with aging, whereas the subcortical gray matter maintains its volume, and the cerebral white matter increases slightly until the 40s and begins to decrease from the 50s.

A subject-specific assessment of measurement errors and their correction in cerebrospinal fluid velocity maps using 4D flow MRI.

PURPOSE: Phase-contrast MRI (PC-MRI) of cerebrospinal fluid (CSF) velocity is used to evaluate the characteristics of intracranial diseases, such as normal-pressure hydrocephalus (NPH). Nevertheless, PC-MRI has several potential error sources, with eddy-current-based phase offset error being non-negligible in CSF measurement. In this study, we assess the measurement error of CSF velocity maps obtained using 4D flow MRI and evaluate correction methods. METHODS: CSF velocity maps of 10 patients with NPH were acquired using 4D flow MRI (velocity-encoding = 5 cm/s). Distributed phase offset error was estimated for a whole 3D background field by polynomial fitting using robust regression analysis. This estimated phase offset error was then used to correct the CSF velocity maps. The estimated error profiles were compared with those obtained using an existing 2D correction approach involving local background information near the region of interest. RESULTS: The residual standard error of the polynomial fitting against the phase offset error extracted from the measured velocities was within 0.2 cm/s. The spatial dependencies of the phase offset errors showed similar tendencies in all cases, but sufficient differences in these values were found to indicate requirement of velocity correction. Differences of the estimated errors among other correction approaches were in the order of 10-2 cm/s, and the estimated errors were in good agreement with those obtained using existing approaches. CONCLUSION: Our method is capable of estimating the measurement error of CSF velocity maps obtained from 4D flow MRI and provides quantitatively reasonable characteristics for the main CSF profile in the cerebral aqueduct in patients with NPH.

Relationship between the characteristics of lower extremity function and activities of daily living in hospitalized middle-aged and older adults with subacute cardiovascular disease.

[Purpose] To clarify the relationship between lower extremity function and activities of daily living and characterize lower extremity function in hospitalized middle-aged and older adults with subacute cardiovascular disease. [Participants and Methods] The Short Physical Performance Battery, 6-minute walk distance, and functional independence measure tests were conducted in 79 inpatients with subacute cardiovascular disease (mean age, 76.7 ± 11.9 years; 34 females). Multiple regression analysis used the functional independence measure score as the dependent variable and the Short Physical Performance Battery and 6-minute walk distance scores as independent variables. Cross-tabulations were performed for each age group, and patients who performed the Short Physical Performance Battery and 6-minute walk distance tests were divided into two groups by their respective cutoff values. [Results] Only the Short Physical Performance Battery (ß=0.568) and 6-minute walk distance (ß=0.479) scores were adopted as significant independent variables in each multiple regression model. The age <75 years group had the most patients with both good lower extremity function and aerobic capacity, whereas the age ≥75 years group had the most patients with both functions impaired. [Conclusion] Although cardiovascular disease is generally associated with decreased aerobic capacity, many older patients with cardiovascular disease in this study had decreased lower extremity function, too.

Association between patients' state upon admission and decline in activities of daily living.

[Purpose] In this study, we aimed to determine the components of activities of daily living that decline easily during hospitalization. [Participants and Methods] We performed a prospective cohort study of 2,819 inpatients who were hospitalized and discharged. We prospectively evaluated the Barthel Index at admission and discharge, age, length of hospital stay, clinical department, and rehabilitation type. We divided the inpatients into two groups based on the Barthel Index score at admission and compared the items of the index at admission and discharge to analyze the characteristics of decline in activities of daily living. [Results] Forty-nine inpatients (2.0%) had declined in activities of daily living. There were no significant between-group differences in age, length of hospital stay, clinical department, or ratio of individual rehabilitation. However, transfer and toilet use remarkably decreased in the group with Barthel Index scores at admission <85, and bathing and ascending/descending remarkably decreased in the group with Barthel Index at admission ≥85. [Conclusion] The characteristics of decrease in each activity of daily living vary, and our results suggested the components that easily declined when inpatients were divided based on their performance of activities of daily living at admission.

Effect of Local Coil Density on Blood Flow Stagnation in Densely Coiled Cerebral Aneurysms: A Computational Study Using a Cartesian Grid Method.

Aneurysm recurrence is the most critical concern following coil embolization of a cerebral aneurysm. Adequate packing density (PD) and coil uniformity are believed necessary to achieve sufficient flow stagnation, which decreases the risk of aneurysm recurrence. The effect of coil distribution on the extent of flow stagnation, however, especially in cases of dense packing (high PD), has received less attention. Thus, the cause of aneurysm recurrence despite dense packing is still an open question. The primary aim of this study is to evaluate the effect of local coil density on the extent of blood flow stagnation in densely coiled aneurysms. For this purpose, we developed a robust computational framework to determine blood flow using a Cartesian grid method, by which the complex fluid pathways in coiled aneurysms could be flexibly treated using an implicit function. This tool allowed us to conduct blood flow analyses in two patient-specific geometries with 50 coil distribution patterns in each aneurysm at clinically adequate PD. The results demonstrated that dense packing in the aneurysm may not necessarily block completely the inflow into the aneurysm and local flow that formed in the neck region, whose strength was inversely related to this local PD. This finding suggests that local coil density in the neck region still plays an important role in disturbing the remaining local flow, which possibly prevents thrombus formation in a whole aneurysm sac, increasing the risk of aneurysm regrowth and subsequent recurrence.

Influence of mouthguards and their palatal design on the stress-state of tooth-periodontal ligament-bone complex under static loading.

BACKGROUND/AIM: The mouthguard (MG) is an effective device to reduce the risk of dental traumatic injuries, but the mechanical effects of wearing a MG and its design are not fully understood. The aim of this study was to evaluate the mechanical influence of wearing a MG and its palatal design on the tooth-periodontal ligament-bone complex (TPBC) by computational analysis using the finite element method. MATERIAL AND METHODS: Three-dimensional subject-specific geometry of the TPBC was reconstructed from medical computed tomography (CT) images. Two patterns of MG geometries were constructed which covered the palatal domain or not (the position of these palatal margins was set at -8 mm (pattern 1) and 4 mm (pattern 2) from the cervical line. Five cases of static mechanical analysis were conducted by changing the location of the loading points from near the cervical line to the tip of the tooth. RESULTS: Wearing a MG decreased strain concentration around the loading point and cervical domain regardless of the MG palatal design. Elastic energy in the periodontal ligament (PDL) and tooth (including enamel and dentin) decreased when the MG was worn, whereas the MG palatal design slightly affected the degree of reduction in the elastic energies. The location of the loading points remarkably affected the elastic energy in the TPBC components and the extent of its reduction due to the MG. CONCLUSIONS: These findings indicated that the protection ability of the MG exerted in the restricted situations of traumatic events occurs regardless of the MG design.

Structural validity of Balance Evaluation Systems Test assessed using factor and Rasch analyses in patients with stroke.

[Purpose] The Balance Evaluation Systems Test (BESTest) is a comprehensive assessment tool, although it is not confined for use in stroke patients. This study aimed to determine the structural validity of the BESTest in self-ambulatory patients with stroke using both factor and Rasch analyses. [Participants and Methods] This retrospective study included 140 self-ambulatory patients with stroke. The structural validity of the BESTest was analyzed according to principal component, exploratory factor, Rasch, confirmatory factor, and correlation analyses. [Results] The analytical results supported a four-factor model comprising 25 items. The four factors included dynamic postural control with gait, static postural control, stepping reaction, and stability limits in sitting. Evidence of high structural validity and reliable internal consistency suggested that the 25-item BESTest is valid and reliable. Each factor was significantly correlated with lower extremity motor function and walking ability. [Conclusion] Eleven items in the BESTest were poorly correlated, and the remaining 25 items were grouped into four factors that demonstrated good structural validity for patients with stroke. Further studies should validate the applicability of the 25-item BESTest four-factor model in a larger sample of patients with stroke in a clinical setting.

Can blood pressure be measured during exercise with an automated sphygmomanometer based on an oscillometric method?

[Purpose] This study investigated the reliability of an automated sphygmomanometer based on an oscillometric method, when used during exercise. [Subjects and Methods] Ten healthy subjects were included. Blood pressure (BP) was measured with an automated sphygmomanometer based on a cuff-oscillometric method. The experiment consisted of five tests: sitting posture at rest, walking with swinging the upper limbs, walking without swinging the upper limbs, walking on a treadmill, and riding a bicycle ergometer. Right and left brachial artery BP was measured twice at the same times. If the difference in systolic BP on bilateral testing was less than 15 mmHg, it was judged to be accurate, and accurate measurement rates were calculated. [Results] BP could not be measured in most limbs on walking with swinging the upper limbs, walking without swinging the upper limbs, or walking on a treadmill. The accurate measurement rates in bilateral limbs were 95.0% in sitting posture at rest, 0.0% on walking with swinging upper limbs, 5.0% on walking without swinging upper limbs, 15.0% on walking on a treadmill, and 65.0% on riding a bicycle ergometer. [Conclusion] An automated sphygmomanometer based on an oscillometric method was useful for BP measurement only at rest.

Computational study on the effects of central retinal blood vessels with asymmetric geometries on optic nerve head biomechanics.

Optic nerve head (ONH) biomechanics are associated with glaucoma progression and have received considerable attention. Central retinal vessels (CRVs) oriented asymmetrically in the ONH are the single blood supply source to the retina and are believed to act as mechanically stable elements in the ONH in response to intraocular pressure (IOP). However, these mechanical effects are considered negligible in ONH biomechanical studies and received less attention. This study investigated the effects of CRVs on ONH biomechanics taking into consideration three-dimensional asymmetric CRV geometries. A CRV geometry was constructed based on CRV centerlines extracted from optical coherence tomography ONH images in eight healthy subjects and superimposed in the idealized ONH geometry established in previous studies. Mechanical analyses of the ONH in response to the IOP were conducted in the cases with and without CRVs for comparison. Obtained results demonstrated that the CRVs induced anisotropic ONH deformation, particularly in the lamina cribrosa and the associated upper neural tissues (prelamina) with wide ranges of spatial strain distributions. These results indicated that the CRVs result in anisotropic deformation with local strain concentration, rather than function to mechanically support in response to the IOP as in the conventional thinking in ophthalmology.

Rasch analysis of the Short Physical Performance Battery in older inpatients with heart failure.

PURPOSE: The physical function of older patients with heart failure (HF) is likely to decline, and the Short Physical Performance Battery (SPPB) is widely used for its evaluation. No study has analyzed the SPPB by using Rasch model in these patients. The aim of this study was to examine the structural validity and item response of the SPPB in older inpatients with HF. MATERIALS AND METHODS: In this multicenter cross-sectional study, we investigated 106 older inpatients with HF. We evaluated the SPPB's rating scale structure, unidimensionality, and measurement accuracy (0 = poor performance to 4 = normal performance). RESULTS: The SPPB rating scale fulfilled the category functioning criteria. All items fit the underlying scale construct. The SPPB demonstrated adequate reliability (person reliability = 0.81) and separated persons into four strata: those with very low, low, moderate, and high physical performance. Item-difficulty measures were -0.59 to 0.96 logits, and regarding the person ability-item difficulty matching for the SPPB, the item was somewhat easy (the mean of person ability = 0.89 logits; mean of item difficulty = 0.00). CONCLUSION: The SPPB has strong measurement properties and is an appropriate scale for quantitatively evaluating physical function in older patients with HF.

For older adults with heart failure (HF), the Short Physical Performance Battery (SPPB) is often used to measure physical performance.Rasch analysis revealed that SPPB had strong measurement properties in older adults with HF.This result may help rehabilitation professionals use the SPPB as a physical performance scale in clinical practice to aid decision-making in intervention planning.

Computational study on hemodynamic effects of left superior pulmonary vein resection and associated physiological changes in the left atrium after left upper lobectomy.

Left upper lobectomy (LUL) with left superior pulmonary vein (LSPV) resection alters the left atrium (LA) physiological states and LA hemodynamics associated with thrombosis, although this underlying mechanism is poorly understood. Therefore, we investigated the effects of LSPV resection and associated LA physiological changes on LA hemodynamics using four-dimensional computed tomography image-based computational simulations. Three cases were considered: the LA before and after LUL extracted from computed tomography images and artificial LSPV resection without physiological changes. Comparisons among the three cases demonstrated that physiological changes associated with LSPV resection are the possible factors that affect the LA hemodynamics after LUL.

Automatic assessment of disproportionately enlarged subarachnoid-space hydrocephalus from 3D MRI using two deep learning models.

Background: Disproportionately enlarged subarachnoid-space hydrocephalus (DESH) is a key feature for Hakim disease (idiopathic normal pressure hydrocephalus: iNPH), but subjectively evaluated. To develop automatic quantitative assessment of DESH with automatic segmentation using combined deep learning models. Methods: This study included 180 participants (42 Hakim patients, 138 healthy volunteers; 78 males, 102 females). Overall, 159 three-dimensional (3D) T1-weighted and 180 T2-weighted MRIs were included. As a semantic segmentation, 3D MRIs were automatically segmented in the total ventricles, total subarachnoid space (SAS), high-convexity SAS, and Sylvian fissure and basal cistern on the 3D U-Net model. As an image classification, DESH, ventricular dilatation (VD), tightened sulci in the high convexities (THC), and Sylvian fissure dilatation (SFD) were automatically assessed on the multimodal convolutional neural network (CNN) model. For both deep learning models, 110 T1- and 130 T2-weighted MRIs were used for training, 30 T1- and 30 T2-weighted MRIs for internal validation, and the remaining 19 T1- and 20 T2-weighted MRIs for external validation. Dice score was calculated as (overlapping area) × 2/total area. Results: Automatic region extraction from 3D T1- and T2-weighted MRI was accurate for the total ventricles (mean Dice scores: 0.85 and 0.83), Sylvian fissure and basal cistern (0.70 and 0.69), and high-convexity SAS (0.68 and 0.60), respectively. Automatic determination of DESH, VD, THC, and SFD from the segmented regions on the multimodal CNN model was sufficiently reliable; all of the mean softmax probability scores were exceeded by 0.95. All of the areas under the receiver-operating characteristic curves of the DESH, Venthi, and Sylhi indexes calculated by the segmented regions for detecting DESH were exceeded by 0.97. Conclusion: Using 3D U-Net and a multimodal CNN, DESH was automatically detected with automatically segmented regions from 3D MRIs. Our developed diagnostic support tool can improve the precision of Hakim disease (iNPH) diagnosis.

Modeling cerebrospinal fluid dynamics across the entire intracranial space through integration of four-dimensional flow and intravoxel incoherent motion magnetic resonance imaging.

BACKGROUND: Bidirectional reciprocal motion of cerebrospinal fluid (CSF) was quantified using four-dimensional (4D) flow magnetic resonance imaging (MRI) and intravoxel incoherent motion (IVIM) MRI. To estimate various CSF motions in the entire intracranial region, we attempted to integrate the flow parameters calculated using the two MRI sequences. To elucidate how CSF dynamics deteriorate in Hakim's disease, an age-dependent chronic hydrocephalus, flow parameters were estimated from the two MRI sequences to assess CSF motion in the entire intracranial region. METHODS: This study included 127 healthy volunteers aged ≥ 20 years and 44 patients with Hakim's disease. On 4D flow MRI for measuring CSF motion, velocity encoding was set at 5 cm/s. For the IVIM MRI analysis, the diffusion-weighted sequence was set at six b-values (i.e., 0, 50, 100, 250, 500, and 1000 s/mm2), and the biexponential IVIM fitting method was adapted. The relationships between the fraction of incoherent perfusion (f) on IVIM MRI and 4D flow MRI parameters including velocity amplitude (VA), absolute maximum velocity, stroke volume, net flow volume, and reverse flow rate were comprehensively evaluated in seven locations in the ventricles and subarachnoid spaces. Furthermore, we developed a new parameter for fluid oscillation, the Fluid Oscillation Index (FOI), by integrating these two measurements. In addition, we investigated the relationship between the measurements and indices specific to Hakim's disease and the FOIs in the entire intracranial space. RESULTS: The VA on 4D flow MRI was significantly associated with the mean f-values on IVIM MRI. Therefore, we estimated VA that could not be directly measured on 4D flow MRI from the mean f-values on IVIM MRI in the intracranial CSF space, using the following formula; e0.2(f-85) + 0.25. To quantify fluid oscillation using one integrated parameter with weighting, FOI was calculated as VA × 10 + f × 0.02. In addition, the FOIs at the left foramen of Luschka had the strongest correlations with the Evans index (Pearson's correlation coefficient: 0.78). The other indices related with Hakim's disease were significantly associated with the FOIs at the cerebral aqueduct and bilateral foramina of Luschka. FOI at the cerebral aqueduct was also elevated in healthy controls aged ≥ 60 years. CONCLUSIONS: We estimated pulsatile CSF movements in the entire intracranial CSF space in healthy individuals and patients with Hakim's disease using FOI integrating VA from 4D flow MRI and f-values from IVIM MRI. FOI is useful for quantifying the CSF oscillation.