Search

In the decommissioning-work environment of a nuclear power plant, accurately identifying the location of radiation sources is necessary to reduce worker doses and develop decontamination plans. In this regard, gamma-ray imagers are promising devices for the visualization of the location of radiation sources. However, they can only estimate the direction where the radiation source is located and not the distance to the source. A previous study has reported a method for identifying the three-dimensional coordinates of a radiation source by measuring from multiple viewpoints using a gamma-ray imager. In some cases, many objects located in an actual decommissioning site limit the accessible area, making it difficult to measure the target area from multiple viewpoints. Thus, the present study devised and demonstrated a method of estimating the distance to the radiation source by measuring from only one direction using a Compton camera, which is a type of gamma-ray imager. The proposed method considered the reconstructed image intensity as proportional to the inverse square of the distance to the radiation source. This approach is useful in accurately locating radiation sources in environments with limited workable areas such as the broken reactor buildings inside the Fukushima Daiichi Nuclear Power Station., Competing Interests: Declaration of competing interest The author declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Shear wave elasticity imaging (SWEI) usually assumes an isotropic material; however, skeletal muscle is typically modeled as a transversely isotropic material with independent shear wave speeds in the directions along and across the muscle fibers. To capture these direction-dependent properties, we implemented a rotational 3-D SWEI system that measures the shear wave speed both along and across the fibers in a single 3-D acquisition, with automatic detection of the muscle fiber orientation. We tested and examined the repeatability of this system's measurements in the vastus lateralis of 10 healthy volunteers. The average coefficient of variation of the measurements from this 3-D SWEI system was 5.3% along the fibers and 8.1% across the fibers. When compared with estimated respective 2-D SWEI values of 16.0% and 83.4%, these results suggest using 3-D SWEI has the potential to improve the precision of SWEI measurements in muscle. Additionally, we observed no significant difference in shear wave speed between the dominant and non-dominant legs along (p = 0.26) or across (p = 0.65) the muscle fibers., Competing Interests: Conflict of interest disclosure Kathryn Nightingale and Mark Palmeri have intellectual property relating to radiation force-based imaging technologies that has been licensed to Siemens, Samsung and Micro Elastic Ultrasound Systems., (Copyright © 2022 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Joint arthropathies often require continuous monitoring of the joint condition, typically performed using magnetic resonance (MR) or ultrasound (US) imaging. US imaging is often the preferred screening or diagnostic tool as it is fast and inexpensive. However, conventional 2-D US has limited capability to compare imaging results between examinations because of its operator dependence and challenges related to repeat imaging in the same location and orientation. Comparison between several imaging sessions is crucial to assess the interval progression of joint conditions. We propose a novel 3-D US scanner for ankle joint assessment that can partially overcome these issues by enabling 3-D imaging. Here, we (i) present the design of the 3-D US ankle scanner system, (ii) validate the geometric reconstruction accuracy of the system, (iii) provide preliminary images of healthy volunteer ankles and (iv) compare 3-D US imaging results with MR imaging. The 3-D ankle scanner consists of a tub filled with water, a linear US probe attached to the wall of the tub and a motorized unit that rotates the US probe 360° around the center of the tub. As the probe rotates, a 3-D US image is formed of the ankle of the patient positioned in the middle of the tub. US probe height, angle and distance from the tub center can be adjusted. The reconstruction accuracy of the system was validated in each of the coordinate directions at different probe angles using two test phantoms. A phantom consisting of numerous Ø200-µm nylon threads with known spacing and a metal rod with machined grooves was used for validation in the horizontal and vertical directions, respectively. The volumetric reconstruction accuracy validation was performed by imaging an agar phantom with two embedded spheres of known volumes and comparing the segmented sphere volume and surface area with the expected. Three-dimensional US and MR images of both ankles of five healthy volunteers were acquired. Distal tibia and proximal talus were segmented in both imaging modalities and the surfaces of these segmentations were compared using the 95% Hausdorff and mean surface distances. The observed mean linear measurement error in all the coordinate directions and over several probe angles was 2.98%. The mean measured volumetric measurement error was 3.45%. The volunteer study revealed useful features for joint assessment present in the 3-D ankle scanner images, such as joint spacing, distal tibia and proximal talus. The mean 95% Hausdorff and mean surface distances between segmentations in 3-D US and MR images were 5.68 ± 0.83 and 2.01 ± 0.30 mm, respectively. In this proof-of-concept study, the 3-D US ankle scanner enabled visualization of the ankle joint features that are useful for joint assessment., Competing Interests: Conflict of interest disclosure Research support for Dr. Andrea S. Doria unrelated to the current research includes that from Baxalta-Shire (research grant), Novo Nordisk (research grant), the Terry Fox Foundation (research grant), the PSI Foundation (research grant), the Society of Pediatric Radiology (research grant) and the Garron Family Cancer Centre (research grant). The other authors have no conflicts of interest to disclose., (Copyright © 2022 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Median nerve swelling is one of the features of carpal tunnel syndrome (CTS), and ultrasound measurement of maximum median nerve cross-sectional area is commonly used to diagnose CTS. We hypothesized that volume might be a more sensitive measure than cross-sectional area for CTS diagnosis. We therefore assessed the accuracy and reliability of 3-D volume measurements of the median nerve in human cadavers, comparing direct measurements with ultrasound images interpreted using deep learning algorithms. Ultrasound images of a 10-cm segment of the median nerve were used to train the U-Net model, which achieved an average volume similarity of 0.89 and area under the curve of 0.90 from the threefold cross-validation. Correlation coefficients were calculated using the areas measured by each method. The intraclass correlation coefficient was 0.86. Pearson's correlation coefficient R between the estimated volume from the manually measured cross-sectional area and the estimated volume of deep learning was 0.85. In this study using deep learning to segment the median nerve longitudinally, estimated volume had high reliability. We plan to assess its clinical usefulness in future clinical studies. The volume of the median nerve may provide useful additional information on disease severity, beyond maximum cross-sectional area., Competing Interests: Conflicts of interest disclosure The authors have no conflicts of interest to declare., (Copyright © 2022 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

This study compared the diagnostic accuracy of percutaneous fistula contrast-enhanced ultrasound (CEUS) combined with 360° 3-D transrectal ultrasound (TRUS) imaging (CEUS + 360°-TRUS) with that of conventional transrectal ultrasound in the diagnosis of complex anal fistulas. A total of 156 patients clinically diagnosed with complex anal fistula from January 2020 to December 2021 were studied and randomly divided into an experimental group (n = 82) and a control group (n = 74). Patients in the experimental group were examined by percutaneous fistula CEUS combined with CEUS + 360°-TRUS, while patients in the control group were examined using TRUS. The detection of fistulas (main tract, branch and internal orifice) and the accuracy of Parks classification were compared between the two groups. Recurrences were followed up at 1, 3 and 6 mo after the surgery. A total of 156 patients were included, aged 23-68 y (average: 37.7 ± 18.2 y). In both groups, the course of disease was <1 mo in 128 cases, 1-2 mo in 22 cases and >3 mo in 6 cases. A total of 474 fistulas were confirmed by surgery in the aforementioned patients, including 224 main fistulas, 250 branch pipes and 254 internal orifices. The CEUS + 360°-TRUS group had 96.87%, 90.41% and 90.14% diagnostic accuracy for the main tract, branch and internal orifice, which was statistically significant (p < 0.001) compared with the 85.00%, 70.00% and 72.46% for the TRUS group, respectively. The overall accuracy of Parks classification of anal fistula in the CEUS + 360°-TRUS group was significantly higher than that in the TRUS group (90.24% vs. 78.38%, p < 0.001). After 6 mo of follow-up, the recurrence rate in the CEUS + 360°-TRUS group was 4.87%, and the recurrence rate in the TRUS group was 18.91%. Percutaneous fistula CEUS combined with transrectal 360° 3-D imaging has significantly higher accuracy than conventional TRUS in the diagnosis of complex anal fistula, especially for anal fistula branches, internal openings and Parks classification and is beneficial in reducing post-operative occurrence of complex anal fistulas., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Currently, colonoscopy is considered the gold standard procedure for diagnosis of colorectal cancer (CRC), the third most common cancer in the United States. However, this technique fails to detect flat adenomas, serrated polyps and advanced adenomas, with miss rates of 34%, 27% and 14%, respectively. These miss rates, more frequent than previously supposed, suggest the need for new CRC screening tools. In the work described here, the potential application of a 40-MHz ultrasound system to generate a sequence of 2-D endoluminal ultrasound biomicroscopy (eUBM-2-D) images of a mouse model of colon cancer was investigated, and this image sequence was used to render eUBM-3-D images and to measure tumor volume. The technique was validated with tissue-mimicking phantoms and used in vivo with mice bearing colon polypoid tumors. Estimated volumes ranged from 0.174-7.909 mm 3 for targets in validation phantoms and from 0.066-6.082 mm 3 for mouse colon tumors., Competing Interests: Conflict of interest disclosure All the authors declare that no conflicts of interest exist regarding the publication of this article., (Copyright © 2021 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Early detection of pathologic variations in an arteriovenous fistula (AVF) is essential for preventing fistula dysfunction in individuals undergoing hemodialysis. This study aimed to evaluate the clinical applicability of 3-D tomographic ultrasound (tUS) for rapid and simple visualization of AVF morphology and pathology. We assessed 53 AVFs in 50 consecutive patients using 3-D tUS including secondary, blinded reading. For all examinations, a high-end ultrasound (US) device was used with linear probe, attached to a tUS system to allow freehand 3-D scanning. Participants were examined by 2-D US and 3-D tUS with different raw data (B-mode, power Doppler, B-flow). Additional angiography was available for 15 participants with scheduled interventions. In all participants, 3-D tUS allowed a 3-D representation of AVFs in angiographic-like images with good image quality. The 2-D US assessment took 7.9 ± 4.0 min. A 3-D power Doppler scan required, on average, 1.4 ± 0.6 min. Diagnostic accuracy of blinded reading for pathologies was high (86.8% for aneurysms and 79.2% for stenoses). Bland-Altman plots showed an excellent correlation of 3-D tUS with 2-D US and angiography. 3-D tUS is an easily and rapidly applicable method for visualizing morphologic and pathologic AVF variations. Color-coded 3-D reconstruction of power Doppler data simplifies detection of perfused aneurysms and stenoses., Competing Interests: Conflict of interest disclosure The authors declare no conflicts of interest. The results presented in this article have not been published previously in whole or part, except in abstract format., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

We analyzed the performance of a mammographically configured, automated breast ultrasound (McABUS) scanner combined with a digital breast tomosynthesis (DBT) system. The GE Invenia ultrasound system was modified for integration with GE DBT systems. Ultrasound and DBT imaging were performed in the same mammographic compression. Our small preliminary study included 13 cases, six of whom had contained invasive cancers. From analysis of these cases, current limitations and corresponding potential improvements of the system were determined. A registration analysis was performed to compare the ease of McABUS to DBT registration for this system with that of two systems designed previously. It was observed that in comparison to data from an earlier study, the McABUS-to-DBT registration alignment errors for both this system and a previously built combined system were smaller than those for a previously built standalone McABUS system., (Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.)

The design and performance of a mammographically configured, dual-sided, automated breast ultrasound (ABUS) 3-D imaging system are described. Dual-sided imaging (superior and inferior) is compared with single-sided imaging to aid decisions on clinical implementation of the more complex, but potentially higher-quality dual-sided imaging. Marked improvement in image quality and coverage of the breast is obtained in dual-sided ultrasound over single-sided ultrasound. Among hypo-echoic masses imaged, there are increases in the mean contrast-to-noise ratio of 57% and 79%, respectively, for spliced dual-sided versus superior or inferior single-sided imaging. The fractional breast volume coverage, defined as the percentage volume in the transducer field of view that is imaged with clinically acceptable quality, is improved from 59% in both superior and inferior single-sided imaging to 89% in dual-sided imaging. Applying acoustic coupling to the breast requires more effort or sophisticated methods in dual-sided imaging than in single-sided imaging., (Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

An ultrasound elasticity microscope was used to map 3-D strain volume in an ex vivo porcine cornea to illustrate its ability to measure the mechanical properties of this tissue. Mechanical properties of the cornea play an important role in its function and, therefore, also in ophthalmic diseases such as kerataconus and corneal ectasia. The ultrasound elasticity microscope combines a tightly focused high-frequency transducer with confocal scanning to produce high-quality speckle over the entire volume of tissue. This system and the analysis were able to generate volume maps of compressional strain in all three directions for porcine corneal tissue, more information than any previous study has reported. Strain volume maps indicated features of the cornea and mechanical behavior as expected. These results constitute a step toward better understanding of corneal mechanics and better treatment of corneal diseases., (Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)