Efficient Imaging Method Research Articles

Low-cost and efficient confocal imaging method for arabidopsis flower

For an extensive period of time apical meristem (SAM) has been considered as a mysterious organ, due to its small, hidden and dynamic structure. Confocal imaging, combined with fluorescent reporters, enables researchers to unveil the mechanisms underlying cellular activities, such as gene expression, cell division, growth patterns and cell-cell communications. Recently, a series of protocols were developed for confocal imaging of inflorescence meristem (IM) and floral meristem (FM). However, the requirement of high configuration, such as the need of a water-dipping lens without coverslip and the specialized turrets associated with fixed-stage microscopes, impedes the wide adoption of these methods. We exploited an improved object slide and matching method aiming to decrease the configuration requirement. Following this protocol, various dry microscope lenses can be selected with flexibility for building 3D images of IM and FM.

An Electrical Impedance Tomography System for Brain Stroke Imaging based on a Lebesgue-Space Inversion Procedure

An electrical impedance tomography (EIT) system for brain stroke monitoring is presented in this paper. The developed setup is composed by an ad-hoc measurement prototype equipped with an efficient imaging method for the reconstruction of the distribution of the electric conductivity of the body under test. In particular, a time-difference formulation is adopted, and the resulting ill-posed equation is solved by means of an iterative procedure performing a regularization in the framework of Lebesgue spaces. The performance of the method has been assessed by means of several numerical simulations. Moreover, a preliminary validation with experimental data has been performed. The obtained results confirm that the approach is able to effectively detect inclusions with different sizes and locations inside the considered head models.

Magnetic-Photoacoustic Dual-Mode Probe for the Visualization of H2S in Colorectal Cancer.

Techniques for the qualitative and quantitative detection of H2S in vivo have attracted considerable attention due to the key role of H2S in various physiological and pathological processes. However, in vivo detection strategies for H2S are mainly based on fluorescence imaging, which is limited by its poor tissue penetration. Moreover, the limitations of single-mode probes are amplified in complex physiological environments. Herein, a core-shell Fe3O4@Cu2O nanoparticle was constructed as a magnetic-photoacoustic dual-mode probe for H2S detection in vitro and in vivo based on the in situ response of Cu2O to endogenous H2S in colon tumors. This probe is expected to greatly improve the accuracy of H2S detection in vivo because it employs two detection methods with complementary advantages. The new probe was experimentally applied to the in vivo and in vitro visualization of H2S in mice with colorectal cancer, validating the in situ reaction-activated dual-detection method. This work establishes a simple and efficient dual-mode imaging method based on a novel trigger mechanism. The findings provide a new strategy for colon cancer detection based on the in situ reactions at tumor sites.

Imaging and Pathological Features of Idiopathic Portal Hypertension and Differential Diagnosis from Liver Cirrhosis

Idiopathic portal hypertension (IPH) mimics liver cirrhosis in many aspects, and no efficient imaging method to differentiate the two diseases has been reported to date. In this study, the imaging and pathological characteristics were analysed for both IPH and cirrhosis. From January 2015 to March 2019, ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) images and pathological results from 16 IPH and 16 liver cirrhosis patients, as well as imaging results of 16 normal patients as a control group, were retrospectively reviewed. The age of the patients was 39 ± 20 years. There was a significant difference in the mean lumen diameter, wall thickness and ratio of thickness to diameter between the IPH and liver cirrhosis patients in the main and sagittal portal veins (P < 0.05), as well as in the lumen diameter and ratio of thickness to diameter between the IPH and liver cirrhosis patients in the Segment 3 (S3) portal vein (P < 0.05). In IPH patients, the main imaging changes were portal vein wall thickening, stenosis or occlusion, a low enhancement area along the portal vein in the delay phase in contrast-enhanced imaging, and a non-homogeneous change in T1WI. The corresponding pathological changes included interlobular vein thickening, stenosis, occlusion, portal area fibrosis, and atrophy or apoptosis of hepatocytes. The main imaging characteristic of liver cirrhosis was a nodular change in T1WI, and the related pathological change was pseudolobule formation. The imaging characteristics of IPH include thickening of the portal vein vascular wall, stenosis of the portal vein lumen and the absence of diffuse cirrhosis-like nodules. These imaging features have a definite pathological basis and could help make differential diagnoses between IPH and cirrhosis.

A Stacked Autoencoder Neural Network Algorithm for Breast Cancer Diagnosis With Magnetic Detection Electrical Impedance Tomography

Magnetic detection electrical impedance tomography (MDEIT) is a novel imaging technique that aims to reconstruct the conductivity distribution with electrical current injection and the external magnetic flux density measurement by magnetic sensors. Aiming at improving the resolution and accuracy of MDEIT and providing an efficient imaging method for breast cancer diagnosis, a new algorithm based on stacked auto-encoder (SAE) neural network is proposed. Both numerical simulation and phantom experiments are done to verify its feasibility. In the numerical simulation, an amount of sample data with different conductivity distribution are calculated. Then a neural network model is established and trained by training these samples. Finally, the conductivity distribution of an imaging target with the anomaly location can be reconstructed by the network model. The reconstruction result of the SAE algorithm is compared with the reconstruction results of the traditional sensitivity matrix (SM) algorithm and the back propagation (BP) neural network algorithm. Under the noise of 30dB, the relative errors of BP algorithm, SM algorithm and SAE algorithm are 137.19%, 24.90% and 15.28% respectively. Result shows by the SAE algorithm, the location of anomalies is reconstructed more accurately, the conductivity value is more closely to the real one and the anti-noise performance is more robust. At last, a breast phantom experiment by self-made platforms is completed to verify the application feasibility of the new algorithm. The relative reconstruction error of conductivity by proposed SAE algorithm can be reduced to 14.56%. The results show that by SAE algorithm, MDEIT can be a promising approach in clinical diagnosis of breast cancer, and it also provide more potential application prospect for the extensive application of MDEIT.

Subependymal Giant Cell Astrocytoma Size Measurement in Tuberous Sclerosis Complex: Noncontrast vs Contrast-Enhanced 3-Dimensional T1-Weighted Magnetic Resonance Imaging (MRI).

Tuberous sclerosis complex is a multisystem genetic disorder characterized by multiorgan hamartomas, seizures, and developmental delay. Current consensus recommendations for tuberous sclerosis complex include brain magnetic resonance imaging (MRI) without and with contrast every 1 to 3 years until age 25 years for subependymal giant cell astrocytoma screening, and more often in patients with known subependymal giant cell astrocytoma. Recent reports in the literature regarding gadolinium deposition have prompted us to investigate the added value of intravenous contrast in this setting. Thirty-nine MRI examinations from 12 tuberous sclerosis complex patients with known subependymal giant cell astrocytoma were retrospectively reviewed for all caudothalamic groove lesions larger than 1 cm. Lesions were measured in 2 planes on both noncontrast and contrast-enhanced axial 3-dimensional (3D) T1-weighted imaging in a randomized fashion by 2 attending pediatric neuroradiologists. Differences in lesion measurements were compared to zero using a 1-sample t test. On average, radiologist A measured lesions 1.1 mm larger in long-axis diameter without contrast (P = .0003), whereas radiologist B measured lesions 0.1 mm larger without contrast (not significant). Differences in lesion measurement were smaller when comparing noncontrast to contrast-enhanced 3D T1-weighted imaging than when comparing radiologist A to radiologist B. Noncontrast axial 3D T1-weighted imaging is similar to contrast-enhanced axial 3D T1-weighted imaging for subependymal giant cell astrocytoma size measurement. It has high accuracy and may be a safer and more efficient imaging method for tuberous sclerosis complex patients who commonly undergo numerous MRI examinations throughout their lifetime. Further studies may be appropriate to determine whether contrast material could be beneficial in certain situations.

Resolution-enhanced imaging through scattering media by high-order correlation.

Super-resolution optical imaging is a rapidly emerging technology enabling many applications. Recently, correlation imaging has shown its capability in imaging beyond the diffraction limit, relying on quantum and statistical properties of light. High-order correlation imaging can further enhance resolution, however, at the expense of complicated algorithms. Here, we experimentally demonstrate a resolution-enhanced method of imaging through scattering media by exploiting high-order correlation of fluorescence light. Based on this method, individual fluorophores' temporal fluctuations are recorded and computed for their distinguished high-order correlations that enable super-resolution. Special designed time sequences are chosen to reduce computation time and memory. Such high-order correlation imaging exhibits reliable performance through scattering media with significant resolution enhancement and background noise reduction. This efficient imaging method paves the way for new biomedical applications.

Ellipsoidal mirror dark-field scanning for detection of circulating tumor cells

The detection of circulating tumor cells (CTCs) plays a very important role in the prevention and treatment of cancer. However, because of the low content of tumor cells in peripheral blood, these cells have always been difficult to detect. An efficient and accurate imaging method, the dark-field scanning imaging method, was innovatively proposed for the detection of CTCs in filtered and colored peripheral blood specimens. Here, the original dark-field scanning system was improved. By introducing an ellipsoidal mirror system, the noise in the sampling process is greatly reduced, and the sampling accuracy is significantly improved. Meanwhile, an automatic identification algorithm was developed to identify and screen CTCs in a large number of blood samples. Comparing with the other CTC detection methods, this method does not require a complex biological enrichment process, which may cause loss and destruction of CTCs.

A near-infrared water-soluble fluorescent probe for the detection of biothiols in living cells and Escherichia coli

An efficient near-infrared imaging method for the selective detection of biothiols in living cells, Escherichia coli and rat liver tissue is developed using an off-on fluorescent probe.

Ultrasound findings in extragenital endometriosis.

We present a report on ultrasound findings in extragenital endometriosis and a literature review accompanied by illustrations. Intestinal endometriosis should be considered in female patients of reproductive age who present with constipation, gastrointestinal bleeding, nausea, vomiting, cramp-like abdominal pain, diarrhoea and pelvic pain. Although definitive preoperative diagnosis of endometriosis is difficult, clinical suspicion and appropriate imaging might prevent extensive surgical procedures with higher morbidity. Contrast-enhanced ultrasound is an efficient non-invasive imaging method without any radiation exposure that supports the early diagnosis of intestinal endometriosis and may help assess the vascularization of endometriotic lesions within the distinct layers of the intestinal wall.

Normal and Injured Ankle Ligaments on Ultrasonography With Magnetic Resonance Imaging Correlation.

Ultrasonography (US) has been increasingly used in the evaluation of ankle ligamentous injuries given its advantages as a dynamic, efficient, noninvasive, and cost-effective imaging method. Understanding the anatomy of the ankle ligaments is critical for correct diagnosis and treatment. This pictorial essay describes and illustrates the US scanning technique and potential pitfalls in evaluating the ankle ligaments and also provides an overview of the US appearance of normal and injured ankle ligaments with magnetic resonance imaging correlation. Highlighted structures include the lateral complex, medial/deltoid complex, spring (calcaneonavicular) ligament complex, and syndesmosis.

Three-Dimensional Terahertz Coded-Aperture Imaging Based on Back Projection.

Terahertz coded-aperture imaging (TCAI) can overcome the difficulties of traditional radar in forward-looking and high-resolution imaging. Three-dimensional (3D) TCAI relies mainly on the reference-signal matrix (RSM), the large size and poor accuracy of which reduce the computational efficiency and imaging ability, respectively. According to the previous research on TCAI, traditional TCAI cannot reduce the heavy computational burden while the improved TCAI achieve reconstructing the target parts of different ranges in parallel. However, large-sized RSM still accounts for the computational complexity of traditional TCAI and the improved TCAI. Therefore, this paper proposes a more efficient imaging method named back projection (BP)-TCAI (BP-TCAI). Referring to the basic principle of BP, BP-TCAI can not only divide the scattering information in different ranges but also project the range profiles into different imaging subareas. In this way, the target parts in different subareas can be reconstructed simultaneously to synthesize the whole 3D target and thus decomposes the computational complexity thoroughly. During the pulse compression and projection processes, the signal-to-noise ratio (SNR) of BP-TCAI is also improved. This present the imaging method, model and procedures of traditional TCAI, the improved TCAI and the proposed BP-TCAI. Numerical experimental results prove BP-TCAI to be more effective and efficient than previous imaging methods of TCAI. Besides, BP-TCAI can also be seen as synthetic aperture radar (SAR) imaging with coding technology. Therefore, BP-TCAI opens a future gate combining traditional SAR and coded-aperture imaging.

Projector-defocusing rectification for Fourier single-pixel imaging.

Fourier single-pixel imaging (FSI) is an efficient single-pixel imaging method of obtaining high-quality (resolution/signal-to-noise ratio) 2D images, which projects sinusoid patterns on the object and reconstructs the image through reflected light. The typical system of FSI consists of a single-pixel detector and a digital projector. However, the defocusing of the projector lens blurs the projected patterns, which results in reduced imaging quality. In this work, we propose the projector-defocusing rectification for FSI, which optimizes projector defocusing for the first time. The proposed method rectifies Fourier coefficients using the amplitude ratio between original and defocused patterns, which we can acquire through a controlled experiment on a whiteboard. The enhancement of imaging quality in imperfect circumstances is demonstrated by simulations and experiments.

An efficacy analysis of whole-body magnetic resonance imaging in the diagnosis and follow-up of polymyositis and dermatomyositis.

ObjectivesTo evaluate the value of whole-body magnetic resonance imaging (WBMRI) in diagnosing muscular and extra muscular lesions in patients with polymyositis (PM) and dermatomyositis (DM).MethodsA retrospective analysis of WBMRI data from PM/DM patients who met the Bohan and Peter diagnostic criteria was performed. X2 test was used to compare the rate of positive diagnosis of newly diagnosed patients using WBMRI, serum creatine kinase test, and EMG. McNemar test was used to compare the performance of WBMRI and chest CT in detecting interstitial lung disease (ILD).ResultsThe study included 129 patients (30 PM cases and 99 DM cases). Of them, 81.4% (105/129) showed a visible inflammatory muscular edema on their WBMRI; 29.5% (38/129) had varying degrees of fatty infiltration (9 cases with clear muscular atrophy). Of the 66 newly diagnosed patients, the positive rates of WBMRI, muscle biopsy, serum creatine kinase test and EMG were 86.4% (57/66), 92.4% (61/66), 71.2% (47/66) and 71.1% (32/45), respectively. There was no significant difference in the positive rates between WBMRI and muscle biopsy (X2 = 1.28, P = 0.258). The WBMRI had a higher positive rate than both serum creatine kinase test (X2 = 4.53, P = 0.033) and EMG (X2 = 3.92, P = 0.047). In addition to muscular changes, WBMRI also detected interstitial lung disease (ILD) in 38 cases (29.5%), osteonecrosis in 15 cases (11.6%), and neoplastic lesions (5 malignant; 7 benign) in 12 cases (9.3%). Of the 61 patients who underwent routine chest CT examinations, the WBMRI and CT revealed ILD in 29 cases and 35 cases respectively. There was no significant difference in the sensitivity between WBMRI and CT (p = 0.146).ConclusionsWBMRI is a sensitive, non-invasive and efficient imaging method. It comprehensively displays the extent of muscular involvement in PM/DM patients, and it has the ability to diagnose other associated extra muscular diseases, such as ILD and systemic malignancy. WBMRI can also help screen steroid-induced osteonecrosis.

Cesarean section scar diverticulum evaluation by saline contrast-enhanced magnetic resonance imaging: The relationship between variable parameters and longer menstrual bleeding.

This study was conducted to determine a more accurate imaging method for the diagnosis of cesarean scar diverticulum (CSD) and to identify the parameters of CSD strongly associated with prolonged menstrual bleeding. We enrolled 282 women with a history of cesarean section (CS) who presented with prolonged menstrual bleeding between January 2012 and May 2015. Transvaginal ultrasound, general magnetic resonance imaging (MRI) and contrast-enhanced MRI were used to diagnose CSD. Five parameters were compared among the imaging modalities: length, width, depth and thickness of the remaining muscular layer (TRM) of CSD and the depth/TRM ratio. Correlation between the five parameters and days of menstrual bleeding was performed. Finally, multivariate analysis was used to determine the parameters associated with menstrual bleeding longer than 14 days. Contrast-enhanced MRI yielded greater length or width or thinner TRM of CSD compared with MRI and transvaginal ultrasound. CSD size did not significantly differ between women who had undergone one and two CSs. Correlation analysis revealed that CSD (P = 0.038) and TRM (P = 0.003) lengths were significantly associated with days of menstrual bleeding. Longer than 14 days of bleeding was defined by cut-off values of 2.15 mm for TRM and 13.85 mm for length. TRM and number of CSs were strongly associated with menstrual bleeding longer than 14 days. CE-MRI is a relatively accurate and efficient imaging method for the diagnosis of CSD. A cut-off value of TRM of 2.15 mm is the most important parameter associated with menstrual bleeding longer than 14 days.

Evaluation of the Diagnostic Role of Bedside Lung Ultrasonography in Patients with Suspected Pulmonary Embolism in the Emergency Department.

Background: Despite the existence of detailed consensus guidelines, challenges remain regarding efficient, appropriate, and safe imaging methods for the diagnosis of suspected pulmonary embolism.Aims: To investigate the role of the wedge sign, B-lines, and pleural effusion seen on bedside lung ultrasound in the diagnosis of pulmonary embolism.Study Design: Diagnostic accuracy study.Methods: During the first evaluation of patients with suspected pulmonary embolism, bedside lung ultrasound was performed, and the B-lines, wedge sign, and pleural effusion were investigated. Computed tomography angiography was used as a confirmatory test and was compared with the lung ultrasound findings.Results: Pulmonary embolism was detected in 38 (38%) patients. In the comparison of bedside lung ultrasound results, statistically significant differences were found between the groups in terms of the B-lines and wedge sign (p=0.005 and p<0.001, respectively). There were no significant differences in terms of effusion (p=0.234). Comparison of these findings with computed tomography angiography of the chest showed weak negative correlations between the groups in terms of B-lines (r=-0297) and a moderately positive correlation in terms of the wedge sign (r=0.523). The sensitivity, specificity, and positive and negative predictive values of lung ultrasound findings alone were low. In the logistic regression analysis, the wedge sign (p<0.01, OR=69.45, 95% CI=6.94-695.17) and B-line (p=0.033, OR=1.96, 95% CI=0.41-8.40) were found to be effective in the diagnosis of pulmonary embolism.Conclusion: Although the role of lung ultrasound has been increasing in the management of critically ill patients, its value is limited and cannot replace the gold standard tests in the diagnosis of pulmonary embolism.

Parcellation of Human Amygdala Subfields Using Orientation Distribution Function and Spectral K-means Clustering.

Amygdala plays an important role in fear and emotional learning, which are critical for human survival. Despite the functional relevance and unique circuitry of each human amygdaloid subnuclei, there has yet to be an efficient imaging method for identifying these regions in vivo. A data-driven approach without prior knowledge provides advantages of efficient and objective assessments. The present study uses high angular and high spatial resolution diffusion magnetic resonance imaging to generate orientation distribution function, which bears distinctive microstructural features. The features were extracted using spherical harmonic decomposition to assess microstructural similarity within amygdala subfields are identified via similarity matrices using spectral k-mean clustering. The approach was tested on 32 healthy volunteers and three distinct amygdala subfields were identified including medial, posterior-superior lateral, and anterior-inferior lateral.

Efficient Terahertz Wide-Angle NUFFT-Based Inverse Synthetic Aperture Imaging Considering Spherical Wavefront.

An efficient wide-angle inverse synthetic aperture imaging method considering the spherical wavefront effects and suitable for the terahertz band is presented. Firstly, the echo signal model under spherical wave assumption is established, and the detailed wavefront curvature compensation method accelerated by 1D fast Fourier transform (FFT) is discussed. Then, to speed up the reconstruction procedure, the fast Gaussian gridding (FGG)-based nonuniform FFT (NUFFT) is employed to focus the image. Finally, proof-of-principle experiments are carried out and the results are compared with the ones obtained by the convolution back-projection (CBP) algorithm. The results demonstrate the effectiveness and the efficiency of the presented method. This imaging method can be directly used in the field of nondestructive detection and can also be used to provide a solution for the calculation of the far-field RCSs (Radar Cross Section) of targets in the terahertz regime.

Efficient compressed imaging method for a microsatellite optical camera.

Imaging integrated with compression is considered the holy grail of microsatellite photography because it improves the degree of integration of the camera system, removing the compression system, high capacity storage system, and high-speed image transmission system, which consume lots of resources of the satellite platform. In this paper, we propose an efficient compressed imaging method for remote sensing photography. We consider wavelet coefficients as pixels of a block-wise megapixel sensor (BMPS). We integrate the saliency information stage into the BMPS to perform compressed sampling (CS) in order to further improve imaging performance. In the compressed sensing process, we use transformed postwavelet coefficients to calculate saliency information of images in the postwavelet domain. According to different regions having different saliency information, the corresponding sensing resources are allocated to perform CS. CS can obtain the compressed discrete sparse samples of the original signal at a much lower sample rate than the Nyquist frequency. The discrete samples signal can be reconstructed by a nonlinear recovery algorithm in the ground. Experimental results show that the proposed compressed imaging method outperforms the traditional saliency-based methods in terms of multiple assessment approaches.

Elemental x-ray imaging using Zernike phase contrast**Project supported by the National Basic Research Program of China (Grant No. 2012CB825801) and the National Natural Science Foundation of China (Grant Nos. 11505188, and 11305173).

We develop an element-specific x-ray microscopy method by using Zernike phase contrast imaging near absorption edges, where a real part of refractive index changes abruptly. In this method two phase contrast images are subtracted to obtain the target element: one is at the absorption edge of the target element and the other is near the absorption edge. The x-ray exposure required by this method is expected to be significantly lower than that of conventional absorption-based x-ray elemental imaging methods. Numerical calculations confirm the advantages of this highly efficient imaging method.