Three-dimensional Volume Reconstruction Research Articles

Dynamic in-situ CT imaging to study meso-structure evolution and fracture mechanism of shale during thermal-mechanical coupling condition

Temperature has a significant impact on the occurrence characteristics and flow properties of oil and gas in shale reservoirs at in-situ conditions. Under thermal–mechanical coupling conditions, the macroscopic deformation instability characteristics and the evolution of the internal microstructure of shale are of great importance for the exploitation of shale oil and gas. However, most studies on the macroscopic and microscopic characteristics of shale only analyze the deformation and instability mechanisms of shale from observations of the post-failure microscopic structures. This paper employs a self-developed THM-CT coupling test system to study the macroscopic deformation characteristics of shale under triaxial compression at real-time temperatures, and simultaneously uses in-situ CT imaging technology to characterize the internal microstructure of shale under different stress levels. Real-time CT porosity obtained via in-situ CT imaging technology represents the mesoscopic structural parameters, together with macroscopic deformation characteristics, delineate the four stages of the entire deformation process in shale: initial compression, linear elastic deformation, yielding deformation, and post-failure. The deformation after peak-stress (σf) in shale is 1–3 times that before peak-stress (σf). The dissolution and softening of clay minerals within the internal micro-lamination of shale, along with the weakening of the internal structure, result in a decline in mechanical parameters such as stress strength (σf) and elastic modulus (E) with increasing temperature. The reconstruction of three-dimensional μCT digital volumes further reconstructs the internal fracture spatial structure under different stress levels during the deformation process, precisely characterizing the dynamic evolution of internal fracture nucleation, expansion, and coalescence during the whole test process. The failure characteristics of shales display notable heterogeneity and anisotropy. Internally, fractures experience a sequence of initiation, formation of vertical and oblique main fractures along the axial direction, and crossing connections between fractures. During test process, multiple occurrences of horizontal secondary micro-fractures extend along weakly cemented lamination, playing a connecting role between the main fractures. Importantly, a real-time quantitative relationship between the macroscopic and microscopic mechanics of rock has been established by linking the mesoscopic damage factor with the applied stress. It was found that the damage factor increases according to a power-law relationship with stress in the yield deformation phase. The variation in the mesoscopic damage factor serves as an intuitive index reflecting the systematic failure of rock, providing an early warning for the impending failure of shale.

Enhancing Patient Comprehension in Skull-Base Meningioma Surgery through 3D Volumetric Reconstructions: A Cost-Effective Approach.

Understanding complex neurosurgical procedures and diseases, such as skull-base meningiomas, is challenging for patients due to the intricate anatomy and the involvement of critical neurovascular structures. Enhanced patient comprehension is crucial for satisfaction and improved clinical outcomes. Patient-specific 3D models have demonstrated benefits in patient education, though they are costly and time-intensive to produce. This study investigates whether the use of 3D volumetric reconstructions with anatomical segmentation, widely available via neuronavigation software, can improve patients' understanding of skull-base meningiomas, surgical procedures, and potential complications. This study included twenty patients with skull-base meningiomas. Three-dimensional volume reconstructions and anatomical segmentations were created using preoperative MRI sequences with neuronavigation software. These reconstructions were used during patient consultations where a surgeon explained key aspects of the disease, the surgical intervention, and potential complications. A questionnaire assessed the patients' perceptions of the utility of these 3D reconstructions. The majority of patients (75%) found the 3D volumetric reconstructions and anatomical segmentations to be more beneficial than MRI images for understanding their disease. Similarly, 75% reported improved comprehension of the surgical approach, and 85% felt that the reconstructions enhanced their understanding of potential surgical complications. Overall, 65% of patients considered the 3D reconstructions valuable in medical consultations. Our study indicates that using accessible, cost-effective, and non-time-consuming 3D volumetric reconstructions with anatomical segmentation enhances patient understanding of skull-base meningiomas. Further research is necessary to confirm these findings, compare these reconstructions with physical 3D models and virtual reality models, and evaluate their impact on patient anxiety regarding the surgical procedure.

Second-order accurate and unconditionally stable algorithm with unique solvability for a phase-field model of 3D volume reconstruction

Three-dimensional (3D) volume reconstruction is an important technique in the fields of 3D printing, artificial limb, and medical diagnostic. This work aims to develop an unconditionally stable algorithm with desired accuracy and unique solvability for a phase-field model of 3D volume reconstruction. Based on scattered points of a target object, a smooth narrow volume is reconstructed by solving a Allen–Cahn-type equation with control function. Since the non-negative property of control function, the evolution of governing equation can associate with an energy dissipation law (i.e., energy stability). By modifying the nonlinear term in governing equation into an appropriate truncated form and utilizing a stabilized Crank–Nicolson-type discretization in time, we develop a linear, second-order accurate, and unconditionally energy-stable time-marching scheme to update the solution. The space is discretized with the finite difference method and the fully discrete energy stability is analytically estimated. We also prove the unique solvability of our proposed time-marching scheme. The accuracy, stability, and capability of reconstructing various 3D volumes are verified via extensive numerical simulations. To facilitate the interested readers, we provide the open source codes of 3D volume reconstruction of a teapot on corresponding author's personal website: https://cfdyang521.github.io.

Dynamic three-dimensional liver volume assessment of liver regeneration in hilar cholangiocarcinoma patients undergoing hemi-hepatectomy.

For patients with hilar cholangiocarcinoma (HC) undergoing hemi-hepatectomy, there are controversies regarding the requirement of, indications for, and timing of preoperative biliary drainage (PBD). Dynamic three-dimensional volume reconstruction could effectively evaluate the regeneration of liver after surgery, which may provide assistance for exploring indications for PBD and optimal preoperative bilirubin value. The purpose of this study was to explore the indications for PBD and the optimal preoperative bilirubin value to improve prognosis for HC patients undergoing hemi-hepatectomy. We retrospectively analyzed the data of HC patients who underwent hemi-hepatectomy in the First Affiliated Hospital of China Medical University from 2012 to 2023. The liver regeneration rate was calculated using three-dimensional volume reconstruction. We analyzed the factors affecting the liver regeneration rate and occurrence of postoperative liver insufficiency. This study involved 83 patients with HC, which were divided into PBD group (n=36) and non-PBD group (n=47). The preoperative bilirubin level may be an independent risk factor affecting the liver regeneration rate (P=0.014) and postoperative liver insufficiency (P=0.016, odds ratio=1.016, β=0.016, 95% CI=1.003-1.029). For patients whose initial bilirubin level was >200 μmol/L (n=45), PBD resulted in better liver regeneration in the early stage (P=0.006) and reduced the incidence of postoperative liver insufficiency [P=0.012, odds ratio=0.144, 95% confidence interval (CI)=0.031-0.657]. The cut-off value of bilirubin was 103.15 μmol/L based on the liver regeneration rate. Patients with a preoperative bilirubin level of ≤103.15 μmol/L shown a better liver regeneration (P<0.01) and lower incidence of postoperative hepatic insufficiency (P=0.011, odds ratio=0.067, 95% CI=0.008-0.537). For HC patients undergoing hemi-hepatectomy whose initial bilirubin level is >200 μmol/L, PBD may result in better liver regeneration and reduce the incidence of postoperative liver insufficiency. Preoperative bilirubin levels ≤103.15 μmol/L maybe recommended for leading to a better liver regeneration and lower incidence of postoperative hepatic insufficiency.

Weighted 3D volume reconstruction from series of slice data using a modified Allen–Cahn equation

In this study, we develop a fast and accurate computational method for a weighted three-dimensional (3D) volume reconstruction from a series of slice data using a phase-field model. The proposed method is based on a modified Allen–Cahn (AC) equation with a fidelity term. The algorithm automatically generates the necessary slices between the given slices by solving the governing equation. To reconstruct a 3D volume, we first set a source slice and target slice. Next, we set the source slice as the initial condition and the target slice as the fidelity function. Finally, we retain the numerical solutions during an evolution as intermediate slices between the source and target slices. There are two criteria for choosing the intermediate slice: One is based on the area of the symmetric difference between the phase-field solution and the target and the other is based on the change of the phase-field solution relative to the area of the target. We use the weighted average of the two criteria. To validate the efficiency and accuracy of the proposed numerical algorithm, several computational experiments are conducted. Computational test results confirm the superior performance of the proposed algorithm.

Study of the Contrast Observed on Carbon by Monte Carlo Simulation on wet-STEM Tomography

Analyzing the structure of the material in the fields of material science needs a very good device and methods. Due to its principle in projected images at various tilt angles and calculation of the three-dimensional volume reconstruction with a distinct algorithm, tomography become an excellent tool for analyzing the 3D structure. Several research has been studied to apply electron tomography in ESEM (Environmental Scanning Electron Microscopy) which gives an opportunity in observing the wet material (hydrated) in the aquatic environment. In this research, we showed the advisability of wet-Carbon compound tomography by simulating the interaction of electron materials. Monte Carlo simulation was applied in this study to calculate the optimum water layer thickness in the wet material detected.Keywords: Carbon, Electron Tomography, Simulation of Monte Carlo, STEM

Three-dimensional volume reconstruction from multi-slice data using a shape transformation

We present a computational method for the 3D volume reconstruction from cross-sectional data. The proposed method is based on the Allen–Cahn (AC) equation with a source term. The source term is related to shape transformation from a source object to a target object. Using the operator splitting method, the governing equation is solved by splitting it into three steps. The numerical solution is obtained explicitly using the Euler's methods and the separation of variables. To reconstruct the 3D object from two slice data, we set one slice as the target data and the other data as the initial data. We solve the governing equation and stack intermediate solutions based on the relative fraction of the symmetric difference of two regions occupied by the target and source data. To demonstrate that the proposed method can reconstruct a 3D model through extracted intermediate slice data during shape transformation, we perform several computational tests. Furthermore, the proposed method is applied to a 3D volume reconstruction from multi-slice data of human vertebra.

Studi Interaksi Materi Elektron Al2O3 dengan Simulasi Monte Carlo dan wet-STEM Electron Tomography

Materials science and biology are both fields that require a three-dimensional (3D) structure characterization method. Tomography is an efficient tool for analyzing the three-dimensional structure of a material. The principle is based on the acquisition of a series of projected images at different tilt angles, and on the calculation of the three-dimensional (3D) volume reconstruction (tomogram) using a special algorithm. Various studies have been developed to perform electron tomography in Environmental Scanning Electron Microscopy (ESEM), which provides access to the observation of hydrated samples in an aquatic environment. In this study we present the feasibility of tomography on wet materials, namely Al2O3 compounds by simulating electron material interactions. From these simulations, we determine the optimum detectable thickness of water in the wet material which is calculated by Monte Carlo simulation. Keyword : Al 2 O 3, Tomography, Monte Carlo Simulation, wet-STEM

Application of 64-Slice Spiral CT Imaging Technology Based on Smart Medical Augmented Reality in the Diagnosis of Foreign Bodies in the Respiratory Tract in Children.

A foreign body in the respiratory tract is one of the common accidental injuries of children in our country, and is usually an important and serious event. Injuries caused by foreign substances in the respiratory tract seriously threaten the health and life of children in Korea and are a great challenge for parents as well. In the process of diagnosis of foreign bodies in the respiratory tract, there is often missed diagnosis or serious complications. Therefore, this article proposes the application of 64-slice spiral CT imaging technology based on smart medical augmented reality in the diagnosis of foreign bodies in the respiratory tract in order to improve the diagnosis of foreign bodies in the respiratory tract, provide help with treatment to improve the prognosis of foreign bodies in the respiratory tract, and reduce the incidence of foreign bodies in the respiratory tract. In this paper, 36 children underwent a 64-slice spiral CT scan of their lungs, and images were transferred to a workstation for multiplanar reconstruction, minimal density projection, three-dimensional volume reconstruction imaging, and CT virtual endoscopic reconstruction, the location, shape, size, and size of the foreign body in contrast with adjacent structural lesions and lesions seen during surgery. Experiments have shown that the left bronchial granulation accounted for 27.3%, the right bronchial granulation 18.75%, the main tracheal granulation 28.6%; there was no significant difference between the left and right bronchial granulation (P > 0.05), while the main tracheal granulation and bilateral bronchial granulation there are significant differences between the shape distributions (P < 0.05). This shows that CT imaging technology has enabled more patients to avoid surgical operations and ensure that the spiral computer can bring the greatest benefits to children. A 64-slice spiral CT scan can diagnose foreign bodies in the child's respiratory tract. The detection rate is high and the diagnostic failure rate is low. The diagnostic rationale provides a reference for early clinical treatment.

Fully 3D Active Surface with Machine Learning for PET Image Segmentation.

In order to tackle three-dimensional tumor volume reconstruction from Positron Emission Tomography (PET) images, most of the existing algorithms rely on the segmentation of independent PET slices. To exploit cross-slice information, typically overlooked in these 2D implementations, I present an algorithm capable of achieving the volume reconstruction directly in 3D, by leveraging an active surface algorithm. The evolution of such surface performs the segmentation of the whole stack of slices simultaneously and can handle changes in topology. Furthermore, no artificial stop condition is required, as the active surface will naturally converge to a stable topology. In addition, I include a machine learning component to enhance the accuracy of the segmentation process. The latter consists of a forcing term based on classification results from a discriminant analysis algorithm, which is included directly in the mathematical formulation of the energy function driving surface evolution. It is worth noting that the training of such a component requires minimal data compared to more involved deep learning methods. Only eight patients (i.e., two lung, four head and neck, and two brain cancers) were used for training and testing the machine learning component, while fifty patients (i.e., 10 lung, 25 head and neck, and 15 brain cancers) were used to test the full 3D reconstruction algorithm. Performance evaluation is based on the same dataset of patients discussed in my previous work, where the segmentation was performed using the 2D active contour. The results confirm that the active surface algorithm is superior to the active contour algorithm, outperforming the earlier approach on all the investigated anatomical districts with a dice similarity coefficient of 90.47 ± 2.36% for lung cancer, 88.30 ± 2.89% for head and neck cancer, and 90.29 ± 2.52% for brain cancer. Based on the reported results, it can be claimed that the migration into a 3D system yielded a practical benefit justifying the effort to rewrite an existing 2D system for PET imaging segmentation.

Estimation of Sex from Patella Measurements in Sichuan Han Population Based on CT-Three-Dimensional Volume Reconstruction Technique

Objective To estimate sex based on patella measurements of Sichuan Han population by computed tomography three-dimensional volume reconstruction technique, and to explore the application value of patella in sex estimation. Methods CT three-dimensional volume reconstruction images of patella of 250 individuals were collected, the four measurement indicators including patellar length, patellar width, patellar thickness, and patellar volume were measured. The t-test was used to determine measurement indicators with sex differences. Fisher discriminant analysis was used to establish the sex discriminant function and the prediction accuracy was calculated by leave-one-out cross validation. Results The sex differences of the four measurement indicators had a statistical significance （P<0.05）. The accuracy rate of the univariate discriminant function established by the patellar length was the highest （82.0%）. The accuracy rates of the all indicators discriminant function and the stepwise discriminant function were 80.4% and 81.6%, respectively. Conclusion It is feasible and accurate to estimate sex of Sichuan Han population by patella measurements with CT three-dimensional volume reconstruction technique. The method may be used as an alternative for sex estimation of Sichuan Han population when other bones with higher accuracy are not available.

Impacts of 3 Different Endodontic Access Cavity Designs on Dentin Removal and Point of Entry in 3-dimensional Digital Models

IntroductionThe purpose of this study was to evaluate the tooth structure theoretically required to be removed in the coronal and cervical regions to accomplish 3 different endodontic access preparations in a novel digital model. The deviation of the center of access cavity from the central fossa will also be measured and compared among the 3 endodontic cavity designs, which in turn may serve as suggested points of entry for different access openings. MethodsTwenty-one maxillary molars and 15 mandibular molars were selected and 3-dimensionally imaged with cone-beam computed tomographic imaging. Three-dimensional (3D) volume reconstructions were made and converted into stereolithography files. Digital access cavity preparation was performed on each 3D reconstruction model with the 3 most commonly used endodontic access preparations: minimally invasive (MI), modified straight-line (MS), and traditional straight-line (TS) techniques. After the access cavity outlines were determined, digital sectioning of each reconstructed 3D tooth model was performed orthogonal to the long axis of the tooth at 3 levels: (1) passing through the central fossa, (2) 1.5 mm apical to the central fossa, and (3) 2 mm apical to the cementoenamel junction. The linear distance from the centroid of the access opening to the central fossa was measured to calculate the point of entry, and the amount of tooth structure removal at the pericervical area was measured to calculate the theoretically minimum amount of linear dentin removal required. Two-way repeated measures analysis of variance was performed for the interactions between different access designs and the amount of cervical dentin removal. Other data were statistically analyzed with 1-way repeated measures analysis of variance. The Tukey post hoc test was used for multiple comparisons. Significance was set at .05. ResultsThe amount of deviation of the center of the access cavity from the central fossa in all test groups was less than 1 mm. The dimensions of access openings differed significantly among the 3 access forms (TS > MS > MI, P < .0001). The amount of required cervical dentin removal was the greatest in the TS method followed by the MS and MI methods (P < .0001). ConclusionsThe central fossa could serve as good starting points in all access preparations in both maxillary and mandibular molars. Dentin removal in the coronal and cervical regions was the greatest in the TS design followed by the MS and MI designs. When comparing different canals in the same access form, less cervical dentin was sacrificed in the palatal canals of maxillary molars and the distal canals of mandibular molars.

Assessment of health-related quality of life in patients prior to carotid body tumor resection.

Background Carotid body tumors represent approximately 0.5% of the total head and neck tumors, and the most common presentation form is an asymptomatic cervical mass. Despite of being most of them asymptomatic the quality of life could be impacted; however, the literature remains silent about this matter. The Short Form 36 (SF-36) is a health-related quality of life (HRQoL) instrument that includes eight domains to assess physical and emotional function in different diseases. The aim of this study was to compare HRQoL in preoperative patients with carotid body tumor and a control paired group. The secondary objective was to compare HRQoL between carotid body tumor patients according to the volume tumor and Shamblin classification. Methods A cross-sectional study that included 23 patients diagnosed with carotid body tumor prior to resection and 23 control patients paired by age and gender was conducted from January 2017 to December 2018. The SF-36 questionnaire was applied in 46 patients. Three-dimensional volume reconstruction and estimation (3DVR) was obtained from a preoperative computed tomography angiography (CTA). Descriptive statistical analysis was performed for demographics and categorical variables were reported by frequencies and percentages. Continuous variables were summarized using median with interquartile ranges (IQR) with 95% confidence interval (CI) and were compared. Differences between medians were analyzed with the Mann–Whitney U test and all statistical tests were two-sided. Results In the carotid body tumor group, the mean age was 55 years, females were more frequently affected 19 (83%). Shamblin I was identified in 9% of patients, Shamblin II in 52% and Shamblin III in 39%. Carotid body tumor laterality were 57% right, 34% left and 9% bilateral tumors. The eight domains that comprise the SF-36 questionnaire were statistically significant when compared to the control group. Conclusion Significant differences were found in all SF-36 domains in carotid body tumor patients in comparison to control subjects, confirming that this neoplasm has negative impact in the general HRQoL.

Assessment of a rectal SPECC lesion by endoluminal ultrasound.

Assessment of a rectal SPECC lesion by endoluminal ultrasound.

Three-Dimensional Volume Reconstruction Using Two-Dimensional Parallel Slices

In this paper, we propose a partial differential equation model for three-dimensional (3-D) volume reconstruction from 2-D slices. The proposed method is based on the modified Cahn--Hilliard equati...

Monitoring of Autophagy and Cell Volume Regulation in Kidney Epithelial Cells in Response to Fluid Shear Stress.

Fluidic shear stress applied to epithelial cells inside the kidney tubules affects cell size in an autophagy-related manner. Here, we describe the technical equipment that we routinely use to apply shear stress on cells, as well as immunoblotting, immunofluorescence, and three-dimensional cell volume reconstruction techniques used in analysis of the influence of this stress on cells and cellular components. By pointing out details of experimental techniques and potential pitfalls, this review will serve as a guide for those interested in study of how shear stress influences cells.

Three-Dimensional Cloud Volume Reconstruction from the Multi-angle Imaging SpectroRadiometer

Characterizing 3-D structure of clouds is needed for a more complete understanding of the Earth’s radiative and latent heat fluxes. Here we develop and explore a ray casting algorithm applied to data from the Multi-angle Imaging SpectroRadiometer (MISR) onboard the Terra satellite, in order to reconstruct 3-D cloud volumes of observed clouds. The ray casting algorithm is first applied to geometrically simple synthetic clouds to show that, under the assumption of perfect, clear-conservative cloud masks, the reconstruction method yields overestimation in the volume whose magnitude depends on the cloud geometry and the resolution of the reconstruction grid relative to the image pixel resolution. The method is then applied to two hand-picked MISR scenes, fully accounting for MISR’s viewing geometry for reconstructions over the Earth’s ellipsoidal surface. The MISR Radiometric Camera-by-camera Cloud Mask (RCCM) at 1.1-km resolution and the custom cloud mask at 275-m resolution independently derived from MISR’s red, green, and blue channels are used as input cloud masks. A wind correction method, termed cloud spreading, is applied to the cloud masks to offset potential cloud movements over short time intervals between the camera views of a scene. The MISR cloud-top height product is used as a constraint to reduce the overestimation at the cloud top. The results for the two selected scenes show that the wind correction using the cloud spreading method increases the reconstructed volume up to 4.7 times greater than without the wind correction, and that the reconstructed volume generated from the RCCM is up to 3.5 times greater than that from the higher-resolution custom cloud mask. Recommendations for improving the presented cloud volume reconstructions, as well as possible future passive remote sensing satellite missions, are discussed.

High resolution single particle cryo-electron microscopy using beam-image shift.

Automated data acquisition is used widely for single-particle reconstruction of three-dimensional (3D) volumes of biological complexes preserved in vitreous ice and imaged in a transmission electron microscope. Automation has become integral to this method because of the very large number of particle images required in order to overcome the typically low signal-to-noise ratio of these images. For optimal efficiency, automated data acquisition software packages typically employ some beam-image shift targeting as this method is both fast and accurate (±0.1 µm). In contrast, using only stage movement, relocation to a targeted area under low-dose conditions can only be achieved in combination with multiple iterations or long relaxation times, both reducing efficiency. Nevertheless it is well known that applying beam-image shift induces beam-tilt and with it a potential structure phase error with a phase error π/4 the highest acceptable value. This theory has been used as an argument against beam-image shift for high resolution data collection. Nevertheless, in practice many small beam-image shift datasets have resulted in 3D reconstructions beyond the π/4 phase error limit. To address this apparent contradiction, we performed cryo-EM single-particle reconstructions on a T20S proteasome sample using applied beam-image shifts corresponding to beam tilts from 0 to 10 mrad. To evaluate the results we compared the FSC values, and examined the water density peaks in the 3D map. We conclude that the phase error does not limit the validity of the 3D reconstruction from single-particle averaging beyond the π/4 resolution limit.

Efficient 3D Volume Reconstruction from a Point Cloud Using a Phase-Field Method

We propose an explicit hybrid numerical method for the efficient 3D volume reconstruction from unorganized point clouds using a phase-field method. The proposed three-dimensional volume reconstruction algorithm is based on the 3D binary image segmentation method. First, we define a narrow band domain embedding the unorganized point cloud and an edge indicating function. Second, we define a good initial phase-field function which speeds up the computation significantly. Third, we use a recently developed explicit hybrid numerical method for solving the three-dimensional image segmentation model to obtain efficient volume reconstruction from point cloud data. In order to demonstrate the practical applicability of the proposed method, we perform various numerical experiments.

Disagreement in middle ear volume estimation between tympanometry and three-dimensional volume reconstruction in the context of tympanic membrane perforation

IntroductionMiddle ear volume (MEV) is a clinically relevant parameter across middle ear diseases. MEV values between these techniques have never before been tested for agreement in ears with perforated tympanic membranes (TMs). MethodsMiddle ears were identified from 36 patients ranging 18–89 years of age with TM perforations who underwent tympanometry and temporal bone computed tomography (CT) between 2005 and 2015. MEVs calculated by both tympanometry and three-dimensional volume reconstruction (3DVR) were analyzed for agreement using Bland Altman plots. The differences between tympanometric and 3DVR MEV values for each given middle ear were characterized across MEV quartiles (1 = smallest; 4 = largest) and across increasing states of middle ear disease using Kruskal–Wallis and Wilcoxon testing with Bonferroni correction. ResultsBland Altman plots demonstrated significant disagreement between MEV measurement techniques. Differences between tympanometric (T) and 3DVR MEV values were significantly greater with increasing average (i.e. (T+3DVR)/2)) MEV per linear regression (p < 0.0001). Significance was demonstrated between fourth and first average MEV quartiles (p = 0.0024), fourth and second quartiles (p = 0.0024), third and first quartiles (p = 0.0048), and third and second quartiles (p = 0.048). Absolute MEV difference was not significantly different across varying states of middle ear disease (p = 0.44). ConclusionStatistically and clinically significant disagreement was demonstrated between tympanometric and 3DVR MEV values. Studies that vary in MEV estimation techniques may be expected to demonstrate significantly different results. These preliminary results suggest that clinicians should endeavor to seek further confirmation when interpreting high tympanometric MEV values.