Two-dimensional Imaging Systems Research Articles

EAF-WGAN: Enhanced Alignment Fusion-Wasserstein Generative Adversarial Network for Turbulent Image Restoration

Because of optical distortion induced by atmospheric turbulence and the limitations of optical devices, acquired images of space objects are blurred and degraded. This effect results in anamorphosis in the output of two-dimensional imaging systems. In this work, we present a novel Enhanced Alignment Fusion-Wasserstein Generative Adversarial Network, called EAF-WGAN, for turbulent image restoration. This model is characterized by the innovative use of two modules, including the Align Module (AM) and the Feature Fusion Module (FFM) in the generator, especially in the process of feature fusion, in which 3D convolution is used. Through 3D convolution, the temporal and spatial information of the input image is obtained. Therefore, the formation mode and intensity of turbulence are not considered and the image can be reconstructed. The ability of EAF-WGAN is proved by algorithmically simulated data, physically simulated data, and real-world data.

Bioimaging of glutathione variation for early diagnosis of hepatocellular carcinoma using a liver-targeting ratiometric near-infrared fluorescent probe.

Reliable biomarkers are crucial for early diagnosis of diseases and precise therapy. Biological thiols (represented by glutathione, GSH) play vital roles in the antioxidant defense system for maintaining intracellular redox homeostasis in organisms. However, the aberrant variation in the cellular concentration of GSH correlates with diverse diseases including cancer. Here, a ratiometric near-infrared fluorescent probe CyO-Disu is constructed for the specific sensing of GSH variation in live cells and mice models of hepatic carcinoma (HCC). CyO-Disu features three key elements, a response moiety of bis(2-hydroxyethyl) disulfide, a near-infrared fluorescence signal transducer of heptamethine ketone cyanine, and a targeting moiety of D-galactose. By virtue of its liver-targeting capability, CyO-Disu was utilized for evaluating GSH fluctuations in primary and metastatic hepatoma living cells. To evaluate the efficacy of CyO-Disuin vivo, orthotopic HCC and pulmonary metastatic hepatoma mice models were employed for GSH imaging using two-dimensional and three-dimensional fluorescence molecular tomographic imaging systems. The bioimaging results offered direct evidence that GSH displayed varied concentrations during the progression of HCC. Therefore, the as-synthesized probe CyO-Disu could serve as a potential powerful tool for the early diagnosis and precise treatment of HCC using GSH as a reliable biomarker.

Comparing the Effects of 2D and 3D Imaging Systems on Laparoscopic Pyeloplasty Outcomes in the Treatment of Adult Ureteropelvic Junction Obstruction.

Background: The aim of this study was to compare the efficacy, safety, and the clinical and perioperative outcomes of two-dimensional (2D) and three-dimensional (3D) laparoscopic imaging systems in adult patients undergoing laparoscopic pyeloplasty in our clinics due to ureteropelvic junction (UPJ) obstruction. Methods: A total of 46 adult patients who had undergone laparoscopic pyeloplasty due to UPJ obstruction were included in the study. Cases that had undergone the operation before January 2019 were retrospectively evaluated with the 2D imaging systems. Cases after that date were evaluated by using the 3D imaging systems, and the operative, perioperative, and postoperative findings of these patients were recorded prospectively. Patients who had undergone laparoscopic pyeloplasty were classified into two groups as the "2D group" and the "3D group." To standardize the preoperative findings, the cases that were operated by a single surgeon experienced in both 2D and 3D imaging systems were included in the study. The demographic characteristics and the clinical findings of the patients were compared between the groups. Results: A total of 41 patients were included in the study. The mean age was 27.7 ± 9.17 years. Among the patients, 23 (56.1%) were in the 2D group and 18 (43.9%) were in the 3D group. No statistically significant difference was observed between groups with regard to the demographic characteristics of the patients. According to the perioperative and postoperative findings of the patients, the duration of the operation was significantly shorter in the 3D group. Conclusion: The duration of the operation was significantly reduced in the 3D image-guided laparoscopic pyeloplasty in the treatment of UPJ obstruction of the adult, compared with 2D image-guided operations. The 3D imaging systems provide a better image quality, an important convenience in intraoperative saturation, and low rates of complication in laparoscopic pyeloplasty, and they may be used safely and effectively.

Digital Photogrammetry for Assessing Medial Canthal Tendon Laxity: Novel Standardized Three-Dimensional Versus Traditional Two-Dimensional Lateral Distraction Test

Few studies quantitatively investigated the degree of medial canthal tendon (MCT) laxity using three-dimensional (3D) stereophotography as two-dimensional (2D) imaging systems are still widely used in periocular anthropometry. Hence, in this study, we aimed to compare 2D and 3D technique in assessing MCT laxity and to investigate the correlation between them. A cross-sectional study was conducted in randomly recruited healthy volunteers with no history of eyelid disease and surgery. Predictor variables were the linear measurements derived from 2D and 3D images, respectively, and the outcome variable was MCT laxity. Covariates including age and sex were also included in our correlation observations. One-side measurements for each image were randomly selected for our study. Bivariate correlation was applied to evaluate the correlation between 2D and 3D measurements. Linear regression was used to investigate the correlation between the predictor and outcome variables. Ninety-five Caucasian volunteers (50 men and 45 women, 95 eyes) between 22 and 84years of age (58.5±16.0years) were included in our study. The 2 sets of measurements for MCT laxity were 3.13±0.75 and 2.62±1.50mm on 2D images (P=.18) and 2.49±1.58 and 2.58±1.72mm on 3D images (P=.23). A significant correlation was observed between 3D measurements and MCT laxity (P<.01), while no significant correlation was found between 2D measurements and MCT laxity (P=.64). Our results revealed that measurements on 3D images could be predictors of MCT laxity and might be applied as a base and a reference for speculating the 3D MCT laxity in further research and clinical evaluation.

Quantification of Cerenkov Luminescence Imaging (CLI) Comparable With 3-D PET Standard Measurements.

Cerenkov luminescence imaging (CLI) is commonly performed using two-dimensional (2-D) conventional optical imaging systems for its cost-effective solution. However, quantification of CLI comparable to conventional three-dimensional positron emission tomography (PET) is challenging using these systems due to both the high attenuation of Cerenkov radiation (CR) on mouse tissue and nonexisting depth resolution of CLI using 2-D imaging systems (2-D CLI). In this study, we developed a model that estimates effective tissue attenuation coefficient and corrects the tissue attenuation of CLI signal intensity independent of tissue depth and size. To evaluate this model, we used several thin slices of ham as a phantom and placed a radionuclide (89Zr and 64Cu) inside the phantom at different tissue depths and sizes (2, 7, and 12 mm). We performed 2-D CLI and MicroPET/CT (Combined small animal PET and Computed Tomography (CT)) imaging of the phantom and in vivo mouse model after administration of 89Zr tracer. Estimates of the effective tissue attenuation coefficient (μeff) for 89Zr and 64Cu were ∼2.4 and ∼2.6 cm−1, respectively. The computed unit conversion factor to %ID/g from 2-D CLI signal was 2.74 × 10−3 μCi/radiance estimated from phantom study. After applying tissue attenuation correction and unit conversion to the in vivo animal study, an average quantification difference of 10% for spleen and 35% for liver was obtained compared to PET measurements. The proposed model provides comparable quantification accuracy to standard PET system independent of deep tissue CLI signal attenuation.

Three-dimensional versus two-dimensional imaging systems in thoracoscopic lobectomy for lung cancer in different year

Objective To compare the clinical application of three-dimensional (3D) and two-dimensional (2D) imaging systems in thoracoscopic lobectomy for non-small cell lung cancer (NSCLC). Methods In 2014 and 2016, the patients with NSCLC undergoing thoracoscopic lobectomy with 2D or 3D imaging systems were performed by a single experienced surgeon. The baseline characteristics and perioperative data of the patients were collected and analyzed. Results In 2014, 19 patients underwent 3D thoracoscopic lobectomy and the other 23 patients underwent 2D thoracoscopic lobectomy. Compared to 2D thoracoscopic lobectomy group, 3D thoracoscopic lobectomy group had a significantly shorter operative time [(147.0±23.9)min vs (179.1±54.4)min, P=0.016], a smaller volume of intraoperative blood loss [(142.1±69.3)ml vs (203.0±90.4)ml, P=0.018]. In 2016, 36 patients underwent 3D thoracoscopic lobectomy and the other 32 patients underwent 2D thoracoscopic lobectomy. No significant differences were found between two groups in terms of preoperative indicators. Conclusions To some extent, 3D thoracoscopy reduces the operation difficulty, shortens the operative time and reduces intraoperative blood loss. However, with the accumulation of surgical experience, 2D can effectively compensate for the disadvantages of thoracoscope. Key words: Thoracoscopy; Lung neoplasms/SU

Three-dimensional object visualization and detection in low light illumination using integral imaging.

Conventional two-dimensional (2D) imaging systems that operate in the visible spectrum may perform poorly in environments under low light illumination. In this work, we present the potential of passive three-dimensional (3D) integral imaging (II) to perform 3D imaging of a scene under low light conditions in the visible spectrum and without the need for a photon counting or cooled CCD camera. Using dedicated algorithms, we demonstrate that the reconstructed 3D integral image is naturally optimum in a maximum likelihood sense in low light levels and in the presence of detector noise enabling object visualization in the scene. The conventional 2D imaging fails due to the limited number of photons. Using 3D imaging, we demonstrate the potential for 3D detection of objects behind occlusion in a photon-starved scene. To the best of our knowledge, this is the first report of experimentally using II sensing under low illumination conditions for 3D visualization and 3D object detection in the presence of obscurations with a conventional image sensor.

Three-Dimensional Versus Two-Dimensional Laparoscopic Cholecystectomy: A Systematic Review.

In the last decades, the three-dimensional (3D) imaging systems have been introduced in an attempt to improve depth perception and image quality during laparoscopic cholecystectomy interventions. The goal of our systematic review was to provide enough convincing evidences on superiority and benefits of 3D over two-dimensional (2D) imaging systems, from both surgeon's and patient's point of view, justifying the cost-effectiveness of newly developed 3D systems. Two authors separately performed a full literature search aiming to find randomized controlled trials evaluating the advantages and disadvantages of 3D versus 2D laparoscopic cholecystectomy procedures. The patients who underwent elective laparoscopic cholecystectomy were included in this study irrespective of their age and sex. Differing opinions between the two authors were reviewed by the third author. A total of 912 articles were initially reviewed by their titles and abstracts for eligibility. After being filtered through predetermined inclusion and exclusion criteria, and excluding the duplicates, only 10 studies underwent the final evaluation by the full text assessment. Eventually, only five randomized controlled studies were included in this study. Operative time and depth perception/image quality were set as the primary and secondary outcomes, respectively. The operative time was significantly shorter in 60% of the studies. Of five studies that evaluated the depth perception and image quality, all five (100%) reported a better depth perception and image quality. 3D imaging systems tend to shorten the operative time compared to 2D systems and result in a better depth perception. More studies and investigations with bigger cohort sizes and using unique 3D visual systems are necessary to justify the cost-effectiveness of the new, more expensive 3D systems.

Effect analysis of three-dimensional and two-dimensional imaging systems in laparoscopic radical resection of rectal cancer

Objective To compare the clinical effect of three-dimensional (3D) and two-dimensional (2D) imaging systems in laparoscopic radical resection of rectal cancer. Methods The retrospective cohort study was adopted. The clinical data of the 97 patients who underwent laparoscopic radical resection of rectal cancer at the Xinmin Branch of the China-Japan Union Hospital of Jilin University between May 2012 and December 2014 were collected. Of 97 patients, 47 undergoing 3D laparoscopic radical resection of rectal cancer were allocated into the 3D group and 50 undergoing 2D laparoscopic radical resection of rectal cancer were allocated into the 2D group. The operation followed strictly tumor-free and total mesorectal excision principles. Observation indicators included: (1) surgical situations: operation time, time of deep lymph nodes dissected, volume of intraoperative blood loss, bleeding volume of obturator lymph nodes dissected, number of lymph nodes dissected, postoperative complications and duration of hospital stay. (2) Follow-up situations: follow-up using outpatient examination and telephone interview was performed to detect the survival of patients and tumor recurrence and metastasis up to December 2015. Measurement data with normal distribution were presented as ±s and comparison between groups was analyzed using the t test. Count data were analyzed using the chi-square test. Results (1) Surgical situations: all the patients underwent successful laparoscopic radical resection of rectal cancer, without conversion to open surgery. Operation time, time of deep lymph nodes dissected, volume of intraoperative blood loss, bleeding volume of obturator lymph nodes dissected, number of lymph nodes dissected and duration of postoperative hospital stay were (134.6±18.5)minutes, (21.2±2.7)minutes, (65±20)mL, (16±3)mL, 23.6±3.5, (8.2±2.3)days in the 3D group and (157.4±17.8)minutes, (25.2±2.5)minutes, (89±27)mL, (23±5)mL, 20.5±2.8, (9.4±2.1)days in the 2D group, respectively, with statistically significant differences between the 2 groups (t=2.999, 3.739, 2.327, 4.221, 2.337, 1.274, P 0.05). (2) Follow-up situations: 75 of 97 patients were followed up for 12-36 months with a median time of 24 months, including 35 in the 3D group and 40 in the 2D group, and they were tumor-free survival. Conclusion Compared with 2D laparoscopic radical resection of rectal cancer, 3D laparoscopic radical resection of rectal cancer can shorten the operation time and reduce tissue damage and intraoperative blood loss, and it is beneficial to deep lymph node dissection. Key words: Rectal neoplasms; Radical resection; Laparoscopy; Three-dimension

Stationary intraoral digital tomosynthesis using a carbon nanotube X-ray source array.

Intraoral dental tomosynthesis and closely related tuned-aperture CT (TACT) are low-dose three-dimensional (3D) imaging modalities that have shown improved detection of multiple dental diseases. Clinical interest in implementing these technologies waned owing to their time-consuming nature. Recently developed carbon nanotube (CNT) X-ray sources allow rapid multi-image acquisition without mechanical motion, making tomosynthesis a clinically viable technique. The objective of this investigation was to evaluate the feasibility of and produce high-quality images from a digital tomosynthesis system employing CNT X-ray technology. A test-bed stationary intraoral tomosynthesis unit was constructed using a CNT X-ray source array and a digital intraoral sensor. The source-to-image distance was modified to make the system comparable in image resolution to current two-dimensional intraoral radiography imaging systems. Anthropomorphic phantoms containing teeth with simulated and real caries lesions were imaged using a dose comparable to D-speed film dose with a rectangular collimation. Images were reconstructed and analysed. Tomosynthesis images of the phantom and teeth specimen demonstrated perceived image quality equivalent or superior to standard digital images with the added benefit of 3D information. The ability to "scroll" through slices in a buccal-lingual direction significantly improved visualization of anatomical details. In addition, the subjective visibility of dental caries was increased. Feasibility of the stationary intraoral tomosynthesis is demonstrated. The results show clinical promise and suitability for more robust observer and clinical studies.

Compressive sensing for direct millimeter-wave holographic imaging.

Direct millimeter-wave (MMW) holographic imaging, which provides both the amplitude and phase information by using the heterodyne mixing technique, is considered a powerful tool for personnel security surveillance. However, MWW imaging systems usually suffer from the problem of high cost or relatively long data acquisition periods for array or single-pixel systems. In this paper, compressive sensing (CS), which aims at sparse sampling, is extended to direct MMW holographic imaging for reducing the number of antenna units or the data acquisition time. First, following the scalar diffraction theory, an exact derivation of the direct MMW holographic reconstruction is presented. Then, CS reconstruction strategies for complex-valued MMW images are introduced based on the derived reconstruction formula. To pursue the applicability for near-field MMW imaging and more complicated imaging targets, three sparsity bases, including total variance, wavelet, and curvelet, are evaluated for the CS reconstruction of MMW images. We also discuss different sampling patterns for single-pixel, linear array and two-dimensional array MMW imaging systems. Both simulations and experiments demonstrate the feasibility of recovering MMW images from measurements at 1/2 or even 1/4 of the Nyquist rate.

In vivo near-infrared fluorescence three-dimensional positioning system with binocular stereovision.

Fluorescence is a powerful tool for in-vivo imaging in living animals. The traditional in-vivo fluorescence imaging equipment is based on single-view two-dimensional imaging systems. However, they cannot meet the needs for accurate positioning during modern scientific research. A near-infrared in-vivo fluorescence imaging system is demonstrated, which has the capability of deep source signal detecting and three-dimensional positioning. A three-dimensional coordinates computing (TDCP) method including a preprocess algorithm is presented based on binocular stereo vision theory, to figure out the solution for diffusive nature of light in tissue and the emission spectra overlap of fluorescent labels. This algorithm is validated to be efficient to extract targets from multispectral images and determine the spot center of biological interests. Further data analysis indicates that this TDCP method could be used in three-dimensional positioning of the fluorescent target in small animals. The study also suggests that the combination of a large power laser and deep cooling charge-coupled device will provide an attractive approach for fluorescent detection from deep sources. This work demonstrates the potential of binocular stereo vision theory for three-dimensional positioning for living animal in-vivo imaging.

Three-dimensional imaging technology offers promise in medicine.

Medical imaging plays an increasingly important role in the diagnosis and treatment of disease. Currently, medical equipment mainly has two-dimensional (2D) imaging systems. Although this conventional imaging largely satisfies clinical requirements, it cannot depict pathologic changes in 3 dimensions. The development of three-dimensional (3D) imaging technology has encouraged advances in medical imaging. Three-dimensional imaging technology offers doctors much more information on a pathology than 2D imaging, thus significantly improving diagnostic capability and the quality of treatment. Moreover, the combination of 3D imaging with augmented reality significantly improves surgical navigation process. The advantages of 3D imaging technology have made it an important component of technological progress in the field of medical imaging.

Automated Three-Dimensional Identification and Tracking of Micro/Nanobiological Organisms by Computational Holographic Microscopy

The ability to sense, track, identify, and monitor biological micro/nanoorganisms in a real-time, automated, and integrated system is of great importance from both scientific and technological standpoints. Such a system and its possible variants would have numerous applications in a wide spectrum of fields, including defense against biological warfare, disease control, environmental health and safety, and medical treatments. In this paper, we review a comprehensive mixture of optical and computational tools developed in our group aiming at real-time sensing and recognition of biological microorganisms. Digital in-line holographic microscopy is used with both coherent and partially coherent illumination to probe the specimen interferometrically. The interference pattern is then recorded on an optoelectronic image sensor and transferred to a computer where special statistical algorithms are performed to segment, recognize, and track the microorganisms within the field of view of the microscope. The advantages of proposed holographic sensing are described compared to conventional two-dimensional imaging systems. In addition, the theoretical aspects and fundamental limitations of digital in-line holographic microscopy are discussed, which determine the relationship between system parameters and achievable performance. The proposed optical-digital integrated system for automated, real-time sensing and recognition of biological microorganisms has been deemed promising with the potential of widespread application. We demonstrate how the proposed techniques function together in a series of experiments.

Use of Confocal Microscopy as a Nondestructive Method in the Study of Ink Jet Dot Formation

The formation of the printing ink dot on the substrate is the final and the most critical phase in the printing process. The ink distribution on the printing surface and the drying mechanism depend on ink characteristics as well as on many other factors, for example, surface energy, roughness, sizing, and porosity. Suitable dot gain and high circularity (near unity) of printed dots predict the final print quality. High deviation from ideal circularity could cause undesired phenomena like wicking and bleeding. The aim of the present study is to determine ink dot formation by three different microscopic methods, optical microscopy (OM), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). The main goal of the authors research was to evaluate the applicability of CLSM as a nondestructive method for three-dimensional visualization in the analysis of ink dot formation on UV ink jet prints. To validate the feasibility of such means in a three-dimensional context, the images obtained are compared to those obtained by traditional two-dimensional imaging systems such as OM and SEM. The authors show that the CLSM produces a replica of the cross-sectioned dot profile as seen in SEM. This means that the CLSM technique can be used to rapidly assess the dot profile without physical sectioning.

Synchrotron X-ray Microtomography: A New Tool to Characterize the Interaction Between Paper and Toner

The interaction between paper and toner depends on paper properties (roughness, paper surface, and tension) and toner properties (granulometry and chemical composition). Deepening the knowledge on fixation and adhesion of toner onto the paper substrate is crucial to improve the end-use properties of paper dedicated to electrophotographic printing. The aim of this article is to introduce and describe a new tool to visualize and analyze this interaction. Three-dimensional (3D) imaging is a key tool used to investigate such a phenomenon. For this reason, synchrotron x-ray microtomography (SXRM) was applied to characterize the toner-paper interaction in a noninvasive and nondestructive manner. To validate the feasibility of such means in a 3D context, the obtained data are compared to those obtained by traditional two-dimensional (2D) imaging systems such as optical profilometry and environmental scanning electron microscopy. SXRM emerges as a crucial tool to get a detailed characterization of the ink layer and of the ink-paper interaction. This is a powerful technique to complete studies carried out by classical means.

Phase contrast, phase retrieval and aberration balancing in shift-invariant linear imaging systems

We treat the problems of phase-contrast image formation, deterministic phase retrieval and aberration balancing, in the imaging of weak objects using two-dimensional shift-invariant linear imaging systems. Three classes of model sample are considered: weak phase objects, weak phase-amplitude objects and single-material weak phase-amplitude objects. For each class of sample we show how the various aberration coefficients, which characterise a given imaging system, contribute to the structure of the associated phase-contrast image. The corresponding inverse problem, of obtaining a closed-form expression for the input wave-field given one or more aberrated phase-contrast images of the same, is then examined. Two sample applications are considered: analyser-crystal phase-contrast imaging of weak objects using hard X-rays, and Zernike-type phase-contrast imaging. We close with a discussion of how coherent and incoherent aberrations may be “balanced” against one another, briefly mentioning the applications of this idea to both “deblur by defocus” and proximity-corrected X-ray lithography.

Microfluidic systems integrated with two-dimensional surface plasmon resonance phase imaging systems for microarray immunoassay

This study reports a microfluidic chip integrated with an arrayed immunoassay for surface plasmon resonance (SPR) phase imaging of specific bio-samples. The SPR phase imaging system uses a surface-sensitive optical technique to detect two-dimensional (2D) spatial phase variation caused by rabbit immunoglobulin G (IgG) adsorbed on an anti-rabbit IgG film. The microfluidic chip was fabricated by using micro-electro-mechanical-systems (MEMS) technology on glass and polydimethylsiloxane (PDMS) substrates to facilitate well-controlled and reproducible sample delivery and detection. Since SPR detection is very sensitive to temperature variation, a micromachine-based temperature control module comprising micro-heaters and temperature sensors was used to maintain a uniform temperature distribution inside the arrayed detection area with a variation of less than 0.3 °C. A self-assembled monolayer (SAM) technique was used to pattern the surface chemistry on a gold layer to immobilize anti-rabbit IgG on the modified substrates. The microfluidic chip is capable of transporting a precise amount of IgG solution by using micropumps/valves to the arrayed detection area such that highly sensitive, highly specific bio-sensing can be achieved. The developed microfluidic chips, which employed SPR phase imaging for immunoassay analysis, could successfully detect the interaction of anti-rabbit IgG and IgG. The interactions between immobilized anti-rabbit IgG and IgG with various concentrations have been measured. The detection limit is experimentally found to be 1 × 10 −4 mg/ml (0.67 nM). The specificity of the arrayed immunoassay was also explored. Experimental data show that only the rabbit IgG can be detected and the porcine IgG cannot be adsorbed. The developed microfluidic system is promising for various applications including medical diagnostics, microarray detection and observing protein–protein interactions.

Excimer laser doping technique for application in an integrated CdTe imaging device

CdTe is an attractive semiconductor material for applications in solid-state high-energy X-ray and γ-ray imaging systems because of its high absorption coefficient, large band gap, good mobility lifetime product of holes and stability at normal atmospheric conditions. We propose a new concept for fabricating an integrated CdTe with monolithic circuit configuration for two-dimensional imaging systems suitable for medical, research or industrial applications and operation at room temperature. A new doping technique has been recently developed that employs excimer laser radiation to diffuse impurity atoms into the semiconductor. Accordingly, heavily doped n- and p-type layers with resistivities less than 1 Ω cm can be formed on the high resistive CdTe crystals. We have further extended this technique for doping with spatial pattern. We will present the laser doping technique and various results thus obtained. Spatially patterned doping is demonstrated and we propose the use of these doping techniques for the fabrication of integrated CdTe two-dimensional imaging systems.

Direct measurement of three-dimensionally reconstructed flow convergence surface area and regurgitant flow in aortic regurgitation: in vitro and chronic animal model studies.

Evaluation of flow convergence (FC) with two-dimensional (2D) imaging systems may not be sufficiently accurate to characterize these often asymmetric, complex phenomena. The aim of this study was to validate a three-dimensional (3D) method for determining the severity of aortic regurgitation (AR) in an experimental animal model. In six sheep with surgically induced chronic AR, 20 hemodynamically different states were studied. Instantaneous regurgitant flow rates were obtained by aortic and pulmonary electromagnetic flow meters. Video composite data of color Doppler flow mapping images were transferred into a TomTec computer after computer-controlled 180 degrees rotational acquisition. Direct measurement of the 3D reconstructed FC surface areas as well as measurements of FC areas estimated with 2D methods with hemispherical and hemielliptical assumptions were performed, and values were multiplied by the aliasing velocity to obtain peak regurgitant flow rates. There was better agreement between 3D and electromagnetically derived flow rates than there was between the 2D and the reference values (r=.94, y=1.0x-0.16, difference=0.02 L/min for the 3D method; r=.80, y=1.6x-0.3, difference=1.2 L/min for the 2D hemispherical method; r=.75, y=0.90x+0.2, difference=-0.20 L/min for the 2D hemielliptical method). Without any geometrical assumption, the 3D method provided better delineation of the FC zones and direct measurements of FC surface areas, permitting more accurate quantification of the severity of AR than the 2D methods.