3D Ultrasound Imaging Techniques Research Articles

Feasibility of a Novel 3D Ultrasound Imaging Technique for Intraoperative Margin Assessment during Tongue Cancer Surgery.

Squamous cell carcinoma (SCC) of the tongue is the most prevalent form of oral cavity cancer, with surgical intervention as the preferred method of treatment. Achieving negative or free resection margins of at least 5 mm is associated with improved local control and prolonged survival. Nonetheless, margins that are close (1-5 mm) or positive (less than 1 mm) are often observed in practice, especially for the deep margins. Ultrasound is a promising tool for assessing the depth of invasion, providing non-invasive, real-time imaging for accurate evaluation. We conducted a clinical trial using a novel portable 3D ultrasound imaging technique to assess ex vivo surgical margin assessment in the operating room. During the operation, resected surgical specimens underwent 3D ultrasound scanning. Four head and neck surgeons measured the surgical margins (deep, medial, and lateral) and tumor area on the 3D ultrasound volume. These results were then compared with the histopathology findings evaluated by two head and neck pathologists. Six patients diagnosed with tongue SCC (three T1 stage and three T2 stage) were enrolled for a consecutive cohort. The margin status was correctly categorized as free by 3D ultrasound in five cases, and one case with a "free" margin status was incorrectly categorized by 3D ultrasound as a "close" margin. The Pearson correlation between ultrasound and histopathology was 0.7 (p < 0.001), 0.6 (p < 0.001), and 0.3 (p < 0.05) for deep, medial, and lateral margin measurements, respectively. Bland-Altman analysis compared the mean difference and 95% limits of agreement (LOA) for deep margin measurement by 3D ultrasound and histopathology, with a mean difference of 0.7 mm (SD 1.15 mm). This clinical trial found that 3D ultrasound is accurate in deep margin measurements. The implementation of intraoperative 3D ultrasound imaging of surgical specimens may improve the number of free margins after tongue cancer treatment.

Elevation Resolution Enhancement Oriented 3D Ultrasound Imaging.

Three-dimensional (3D) ultrasound imaging can be accomplished by reconstructing a sequence of two-dimensional (2D) ultrasound images. However, 2D ultrasound images usually suffer from low resolution in the elevation direction, thereby impacting the accuracy of 3D reconstructed results. The lateral resolution of 2D ultrasound is known to significantly exceed the elevation resolution. By combining scanning sequences acquired from orthogonal directions, the effects of poor elevation resolution can be mitigated through a composite reconstructing process. Moreover, capturing ultrasound images from multiple perspectives necessitates a precise probe positioning method with a wide angle of coverage. Optical tracking is popularly used for probe positioning for its high accuracy and environment-robustness. In this paper, a novel large-angle accurate optical positioning method is used for enhancing resolution in 3D ultrasound imaging through orthogonal-view scanning and composite reconstruction. Experiments on two phantoms proved that our method could significantly improve reconstruction accuracy in the elevation direction of the probe compared with single-angle parallel scanning. The results indicate that our method holds the potential to improve current 3D ultrasound imaging techniques.

Development of Automatic Assessment Framework for Spine Deformity Using Freehand 3-D Ultrasound Imaging System.

A 3-D ultrasound (US) imaging technique has been studied to facilitate the diagnosis of spinal deformity without radiation. The objective of this article is to propose an assessment framework to automatically estimate spinal deformity in US spine images. The proposed framework comprises four major components, a US spine image generator, a novel transformer-based lightweight spine detector network, an angle evaluator, and a 3-D modeler. The principal component analysis (PCA) and discriminative scale space tracking (DSST) method are first adopted to generate the US spine images. The proposed detector is equipped with a redundancy queries removal (RQR) module and a regularization item to realize accurate and unique detection of spine images. Two clinical datasets, a total of 273 images from adolescents with idiopathic scoliosis, are used for the investigation of the proposed framework. The curvature is estimated by the angle evaluator, and the 3-D mesh model is established by the parametric modeling technique. The accuracy rate (AR) of the proposed detector can be achieved at 99.5%, with a minimal redundancy rate (RR) of 1.5%. The correlations between automatic curve measurements on US spine images from two datasets and manual measurements on radiographs are 0.91 and 0.88, respectively. The mean absolute difference (MAD) and standard deviation (SD) are 2.72° ± 2.14° and 2.91° ± 2.36° , respectively. The results demonstrate the effectiveness of the proposed framework to advance the application of the 3-D US imaging technique in clinical practice for scoliosis mass screening and monitoring.

Investigation of 3D Reconstruction Algorithms For Wireless Freehand Ultrasound Imaging System.

The handheld 3D ultrasound imaging technique based on position tracking systems has been rapidly developed and widely applied in recent decades. The objectives of this study are to investigate the performance and accuracy of different 3D reconstruction algorithms including Voxel Nearest Neighbor (VNN), Pose Optimization Based (POB), and Implicit Representation (IR) methods. The high-precision phantom was used as the validation model to measure 2D/3D distance on the reconstructed image volume, and the measurements were evaluated with the true values obtained by caliber. The results indicated that the IR method presented the best reconstruction visualization and the smallest reconstruction errors for different motion cases. It demonstrated that the neural network-based reconstruction method can improve image quality and reduce reconstruction errors for the wireless freehand 3D ultrasound imaging systems.Clinical Relevance- This study validates the accuracy and precision of the different reconstruction algorithms for freehand 3D ultrasound imaging systems.

Clinical Importance of 3D Volography in Breast Imaging.

The clinical applications of the volography algorithm and concomitant refraction-corrected reflection algorithm as described in Chap. 10 are discussed here. Comparisons with an H&E stained image, discussion of glandular tissue visibility, related biomarkers, segmentation accuracy and capabilities, microcalcification and cyst detection and analysis, and various VGA and clinical studies show the unique capabilities of the method. The accuracy of the fibroglandular segmentation and its relevance to breast density in imaging is mentioned. The compatibility with artificial intelligence (AI) is shown and clinical results discussed, concluding that low-frequency 3D ultrasound volography is a powerful 3D ultrasound imaging technique for microanatomic and quantitative features of the breast with good potential for AI utilization to provide an imaging technique that will quantitatively improve clinical performance.

Light-Convolution Dense Selection U-Net (LDS U-Net) for Ultrasound Lateral Bony Feature Segmentation

Scoliosis is a widespread medical condition where the spine becomes severely deformed and bends over time. It mostly affects young adults and may have a permanent impact on them. A periodic assessment, using a suitable modality, is necessary for its early detection. Conventionally, the usually employed modalities include X-ray and MRI, which employ ionising radiation and are expensive. Hence, a non-radiating 3D ultrasound imaging technique has been developed as a safe and economic alternative. However, ultrasound produces low-contrast images that are full of speckle noise, and skilled intervention is necessary for their processing. Given the prevalent occurrence of scoliosis and the limitations of scalability of human expert interventions, an automatic, fast, and low-computation assessment technique is being developed for mass scoliosis diagnosis. In this paper, a novel hybridized light-weight convolutional neural network architecture is presented for automatic lateral bony feature identification, which can help to develop a fully-fledged automatic scoliosis detection system. The proposed architecture, Light-convolution Dense Selection U-Net (LDS U-Net), can accurately segment ultrasound spine lateral bony features, from noisy images, thanks to its capabilities of smartly selecting only the useful information and extracting rich deep layer features from the input image. The proposed model is tested using a dataset of 109 spine ultrasound images. The segmentation result of the proposed network is compared with basic U-Net, Attention U-Net, and MultiResUNet using various popular segmentation indices. The results show that LDS U-Net provides a better segmentation performance compared to the other models. Additionally, LDS U-Net requires a smaller number of parameters and less memory, making it suitable for a large-batch screening process of scoliosis without a high computational requirement.

Freehand three-dimensional ultrasound imaging of carotid artery using motion tracking technology

Ultrasound imaging has been extensively used for determining the severity of carotid atherosclerotic stenosis. In particular, the morphological characterization of carotid plaques can be performed for risk stratification of patients. However, using 2D ultrasound imaging for detecting morphological changes in plaques has several limitations. Due to the scan was performed on a single longitudinal cross-section, the selected 2D image is difficult to represent the entire morphology and volume of plaque and vessel lumen. In addition, the precise positions of 2D ultrasound images highly depend on the radiologists’ experience, it makes the serial long-term exams of anti-atherosclerotic therapies are difficult to relocate the same corresponding planes by using 2D B-mode images. This has led to the recent development of three-dimensional (3D) ultrasound imaging, which offers improved visualization and quantification of complex morphologies of carotid plaques. In the present study, a freehand 3D ultrasound imaging technique based on optical motion tracking technology is proposed. Unlike other optical tracking systems, the marker is a small rigid body that is attached to the ultrasound probe and is tracked by eight high-performance digital cameras. The probe positions in 3D space coordinates are then calibrated at spatial and temporal resolutions of 10μm and 0.01s, respectively. The image segmentation procedure involves Otsu’s and the active contour model algorithms and accurately detects the contours of the carotid arteries. The proposed imaging technique was verified using normal artery and atherosclerotic stenosis phantoms. Human experiments involving freehand scanning of the carotid artery of a volunteer were also performed. The results indicated that compared with manual segmentation, the lowest percentage errors of the proposed segmentation procedure were 7.8% and 9.1% for the external and internal carotid arteries, respectively. Finally, the effect of handshaking was calibrated using the optical tracking system for reconstructing a 3D image.

Maxilla-nasion-mandible (MNM) angle: an indicator to assess fetal facial profile in first-trimester of pregnancy.

ObjectiveThe aim of this study was to observe whether there existed significant differences in the maxilla–nasion–mandible angle (MNM) between the first- and second-trimester of pregnancy, and to observe its predictive values for trisomy 18.MethodsTwo experienced ultrasonologists used 2D and 3D ultrasound imaging techniques to obtain the facial sagittal sections of fetuses in the first-trimester of pregnancy (crown-rump length 45–84 mm), respectively, so as to measure MNM.ResultsMNM could be measured in 91 % of normal fetuses, and the measurement differences by different operators in different groups were <1.1°; average MNM was 11.0°, and no significant change was observed in different gestational ages (P = 0.15). The average of MNMs in fetuses with trisomy 18 was 16.6°, which were all higher than the 95th percentile of normal measurement data. The sensitivity and specificity of increased MNM on the abnormal detection of trisomy 18 were 54.7 and 97.4 %, respectively.ConclusionsThe feasibility and reproducibility of measuring MNM in early pregnancy were good. MNM had certain suggestive roles for aneusomic chromosomal abnormalities, especially for fetuses with trisomy 18.

Freehand 3D Ultrasound to Measure Thrombus Volume in Patients with Acute Deep-Vein Thrombosis

Objective —Current imaging techniques are limited in their ability to quantify thrombus burden, progression, or resolution in patients with acute deep-vein thrombosis (DVT). These assessments are critical measures of therapeutic success when thrombolytic or thrombectomy treatment protocols are used for DVT. We have developed a novel freehand three-dimensional (3D) ultrasound method to measure thrombus volume. In this study, we evaluated the reliability of this new technology. Methods —We studied consecutive hospital inpatients with a first episode of acute DVT. Treatment decisions were not influenced by the study protocol. A combination of routine imaging in grayscale, color-flow, and power-Doppler modes along-with freehand 3D volumetric imaging with a linear transducer attached to an external tracking sensor was performed using a personal computer–based ultrasound scanner. Image-processing software loaded on the personal computer was used to process and reconstruct the serial cross-sectional images of the affected veins and outlined thrombus into a composite 3D image. Imaging and processing was performed twice by one sonographer, and repeated once by another sonographer. Results —The mean age of patients was 56.7 ± 15 years; 40% were women. A total of 70% of DVTs were in the lower extremity and 60% received anticoagulation. Thrombus volume was reliably determined by our protocol. The mean inter- and intraobserver differences in measurements were −0.09 ± 0.59 cm3 and 0.23 ± 0.43 cm3 (mean ± SD), which were well within 2 SD (Bland Altman statistics) of the mean volumes. Measurements of the second sonographer correlated well with those of the first (regression slope = 0.95 ± 0.07, p = 0.001) and those of the first observation correlated with the second observation performed by the same sonographer (regression slope = 0.91 ± 0.03, p = 0.001). Interrater agreement was good between the two sonographers (kappa = 0.71) and between two measurements by the same sonographer (kappa = 0.82). Conclusions —We have developed a novel freehand 3D-ultrasound imaging technique and protocol that reliably measures venous thrombus volume. There is good agreement in measurements between two observers and repeated measurements by one observer. The technique can be readily adapted for routine clinical practice. This protocol will be of increasing value as the appreciation for the deleterious effects of residual thrombus after DVT increases; and the use of aggressive thrombus removal treatments for acute DVT increases.

Characterization of controlled bone defects using 2D and 3D ultrasound imaging techniques

Ultrasound is emerging as an attractive alternative modality to standard x-ray and CT methods for bone assessment applications. As of today, however, there is a lack of systematic studies that investigate the performance of diagnostic ultrasound techniques in bone imaging applications. This study aims at understanding the performance limitations of new ultrasound techniques for imaging bones in controlled experiments in vitro. Experiments are performed on samples of mammalian and non-mammalian bones with controlled defects with size ranging from 400 µm to 5 mm. Ultrasound findings are statistically compared with those obtained from the same samples using standard x-ray imaging modalities and optical microscopy. The results of this study demonstrate that it is feasible to use diagnostic ultrasound imaging techniques to assess sub-millimeter bone defects in real time and with high accuracy and precision. These results also demonstrate that ultrasound imaging techniques perform comparably better than x-ray imaging and optical imaging methods, in the assessment of a wide range of controlled defects both in mammalian and non-mammalian bones. In the future, ultrasound imaging techniques might provide a cost-effective, real-time, safe and portable diagnostic tool for bone imaging applications.

Real-Time 3D Imaging Methods using 2D Phased Arrays Based on Synthetic Focusing Techniques

A fast 3D ultrasound imaging technique using a 2D phased array transducer based on the synthetic focusing method for nondestructive testing or medical imaging is proposed. In the proposed method, each column of a 2D array is fired successively to produce transverse fan beams focused at a fixed depth along a given longitudinal direction and the resulting pulse echoes are received at all elements of a 2D array used. After firing all column arrays, a frame of high-resolution image along a given longitudinal direction is obtained with dynamic focusing employed in the longitudinal direction on receive and in the transverse direction on both transmit and receive. The volume rate of the proposed method can be increased much higher than that of the conventional 2D array imaging by employing an efficient sparse array technique. A simple modification to the proposed method can further increase the volume scan rate significantly. The proposed methods are verified through computer simulations.

The use of three-dimensional ultrasound imaging in breast biopsy and prostate therapy

Minimally invasive techniques are rapidly replacing traditional practices because they result in improved benefits for patients, health care providers, payers, employers and hospitals. While two-dimensional (2D) imaging has been used to guide interventional procedures for many decades, the use of three-dimensional (3D) imaging of the anatomy has the potential to provide more accurate and less variable interventional guidance and monitoring options. Although 3D magnetic resonance imaging (MRI), computed tomography (CT) and angiography are important modalities, the development of 3D ultrasound imaging techniques that are capable of acquiring B-mode, color Doppler and power Doppler images, has allowed the development of image-guided therapy and surgery approaches that are making breast biopsy and prostate therapy more accurate and less variable. The use of 3D ultrasound has the potential to provide inexpensive and near real-time views of the anatomy and pathology enabling minimally invasive interventional procedures. In this paper we present the principles and advantages of 3D ultrasound imaging, review some of the implementations techniques, and present new applications in image-guided prostate therapy and breast biopsy.

3D ultrasound imaging of the carotid arteries.

Although ultrasonography is an important cost-effective imaging modality, technical improvements are needed before its full potential is realized for accurate and reproducible monitoring of carotid disease and plaque burden. 2D viewing of 3D anatomy, using conventional ultrasonography limits our ability to quantify and visualize carotid disease and is partly responsible for the reported variability in diagnosis and monitoring of disease progression. Efforts of investigators have focused on overcoming these deficiencies by developing 3D ultrasound imaging techniques that are capable of acquiring B-mode, color Doppler and power Doppler images of the carotid arteries using existing conventional ultrasound systems, reconstructing the information into 3D images, and then allowing interactive viewing of the 3D images on inexpensive desktop computers. In addition, the availability of 3D ultrasound images of the carotid arteries has allowed the development of techniques to quantify plaque volume and surface morphology as well as allowing registration with other 3D imaging modalities. This paper describes 3D ultrasound imaging techniques used to image the carotid arteries and summarizes some of the developments aimed at quantifying plaque volume and morphology.

Three-dimensional ultrasound imaging and its use in quantifying organ and pathology volumes.

Although ultrasonography is an important cost-effective imaging modality, technical improvements are needed before its full potential is realized for accurate and reproducible monitoring of disease progression or regression. Two-dimensional viewing of three-dimensional anatomy, using conventional ultrasonography, limits our ability to quantify and visualize pathology and is partly responsible for the reported variability in diagnosis and monitoring of disease progression. Efforts of investigators have focused on overcoming these deficiencies by developing 3D ultrasound imaging techniques that are capable of acquiring B-mode images using existing conventional ultrasound systems, reconstructing the information into 3D images, and then allowing interactive viewing of the 3D images on inexpensive desktop computers. In addition, the availability of 3D ultrasound images has allowed the development of manual and semi-automated techniques to quantify normal and abnormal anatomical volumes. In this paper we review our semi-automated 3D segmentation approaches for segmenting the surface of the carotid arteries and plaques, and segmenting the prostate. These techniques demonstrate that efficient segmentation techniques can be used with 3D ultrasound images to quantify anatomical organ volumes and morphology.

3D ultrasound imaging: applications in image-guided therapy and biopsy

The use of conventional 2D ultrasonography to view 3D anatomy limits our ability to plan and guide interventional procedures. CT and MRI have been used in planning and guiding these procedures due to their ability to provide 3D images with accurate depiction of anatomy. Recent development of 3D ultrasound imaging techniques that are capable of acquiring B-mode, color Doppler and power Doppler images, has allowed the development of image-guided therapy and surgery approaches. Because ultrasound imaging is an inexpensive and compact imaging modality, it is particularly suited for applications in prostate therapy, breast biopsy and monitoring of disease progression in response to therapy.