3D Ultrasound Research Articles

Methodology Used in Studies Aimed at Measuring Fetal Soft Tissues by 2D Ultrasound for the Screening of Large for Gestational Age Fetuses: A Systematic Review.

Management of suspected large for gestational age (LGA) fetuses remains unclear because ultrasound-estimated fetal weight (EFW) is not accurate. This was a systematic review of observational studies on fetal soft tissues measurements used alone or in combination to create a new EFW formula, to improve the screening for LGA fetuses. Studies were scored using a predefined set of independently agreed methodological criteria and an overall quality score was assigned for study design, statistical analysis, and reporting methods. There is a need to standardize methodologies for soft fetal tissue measurements. We propose a set of suggestions for this purpose.

Verification of intra- and inter-atrial conduction during Bachmann's bundle pacing using longitudinal bi-atrial strain

Abstract Introduction Although atrial septal pacing has been reported to reduce atrial fibrillation (AF) burden, there is less evidence regarding its effect on the prevention of permanent AF and the improvement of long-term clinical outcomes. However, Bachmann's bundle pacing (BBp), which features P-wave morphology similar to sinus rhythm and shortened P-wave duration (PWD), was reported to significantly reduce permanent AF recurrences and occurrences compared with right atrial appendage pacing (RAAp) and non-specific right septal pacing. Purpose Possible mechanisms for AF suppression with BBp are that fast inter-atrial conduction through BB decreases global atrial activation time and the dispersion of the overall atrial refractoriness, and it prevents the decrease in left ventricular filling and increase in left atrial pressure associated with delayed left atrial contraction. Intra-and inter-atrial conduction during BBp was evaluated using longitudinal bi-atrial strain. Methods In patients with successful BBp implantation defined by electrocardiographic criteria using SelectSecure pacing lead and C315 delivery catheter (Medtronic, Inc), both left atrium (LA) and right atrium (RA) global longitudinal strain (GLS) in simultaneous phases were measured using Philips Ultrasound Workspace 2D Strain in apical 4-chamber view during atrial pacing to assess intra- and inter-atrial conduction delay. The atrial GLS were measured semi-automatically, and the strain rate was analyzed in the three segments of septal wall, lateral wall, and roof and their average. The negative peak of strain rate during atrial systole was the starting point of atrial contraction, and time to peak (TTP) was measured. The difference in TTP between septal and lateral walls in each atrium was measured as intra-atrial conduction delay and the difference in average TTP between LA and RA as inter-atrial conduction delay. Results Ten patients who underwent successful BBp were enrolled (Sick sinus syndrome: 3, advanced atrioventricular block: 2, complete atrioventricular block: 5). At implantation, bipolar atrial electrogram amplitude was 2.03±0.93 mV, atrial lead impedance was 632.7±157.6 Ω, and atrial pacing threshold was 0.7±0.2 V at 0.4 ms. The PWD during sinus rhythm on the 12-lead ECG was 132.8±10.6 ms, while during BBp it was 108.0±11.9 ms, which was significantly shorter in the BBp group (p<0.001). The intra-atrial conduction delay in RA and LA was 10.9 ± 12.1 ms and 12.1 ± 17.3 ms, respectively, and the inter-atrial conduction delay was 6.6 ± 8.6 ms. On the other hand, for the 10 RAAp and 10 sinus rhythm patients as control groups, the inter-atrial conduction delay was 29.7±13.8 ms and 8.5±9.5 ms, respectively. BBp had significantly less inter-atrial conduction delay than RAAp (p=0.005) and was comparable to sinus rhythm (p=0.719). Conclusion Longitudinal bi-atrial strain suggested that BBp significantly reduced inter-atrial delay and it might be effective in AF suppression.Longitudinal bi-atrial strain

Prenatal phthalate exposure and pubertal development in 16-year-old daughters: reproductive hormones and number of ovarian follicles.

Is there a possible association between prenatal phthalate exposure and late effects in teenage daughters with respect to reproductive hormone levels, uterine volume, and number of ovarian follicles? Our study showed subtle associations between phthalate metabolite concentrations in maternal serum from pregnancy or cord blood and LH and insulin-like growth factor 1 (IGF-1) levels as well as uterine volume in their daughters 16 years later. Endocrine-disrupting environmental chemicals may adversely affect human reproductive health, and many societies have experienced a trend toward earlier puberty and an increasing prevalence of infertility in young couples. The scientific evidence of adverse effects of foetal exposure to a large range of chemicals, including phthalates, on male reproductive health is growing, but very few studies have explored effects on female reproduction. This follow-up study included 317 teenage daughters who were part of the Copenhagen Mother-Child Cohort, a population-based longitudinal birth cohort of 1210 females born between 1997 and 2002. A total of 317 female participants (median age 16 years) were examined for weight, height, and menstrual pattern. A serum sample was analysed for concentrations of reproductive hormones, and trans-abdominal 3D ultrasonography was performed to obtain the number of ovarian follicles, ovarian and uterine size. Prenatal maternal serum samples were available for 115 females, and cord blood samples were available for 118 females. These were analysed for concentrations of 32 phthalate metabolites. Weighted quantile sum regression was used for modelling associations of combined prenatal phthalate exposure with the reproductive outcomes in post-menarcheal females. In bivariate correlation analyses, negative significant associations were found between several prenatal phthalate metabolite concentrations and serum hormone concentrations (testosterone, 17-OH-progesterone, and IGF-1) as well as number of ovarian follicles in puberty. Positive significant correlations were found between prenatal phthalate exposure and FSH and sex hormone-binding globulin concentrations. Combined analyses of phthalate exposure (weighted quantile sums) showed significant negative associations with IGF-1 concentration and uterine volume as well as a significant positive association with LH concentration. Phthalate metabolites were measured in serum from single prenatal maternal blood samples and cord blood samples. Potential concomitant exposure to other endocrine-disrupting environmental chemicals before or after birth was not controlled for. The study population size was limited. Our results support the need for further research into possible adverse effects of environmental chemicals during foetal development of the female reproductive system. The work was supported by The Center on Endocrine Disruptors (CeHoS) under The Danish Environmental Protection Agency and The Ministry of Environment and Food (grant number: MST-621-00 065). No conflicts of interest are declared. N/A.

Complementing Mammography Screening with Automated 3D Ultrasound in Women with High-Density Breasts

Background. In early breast screening structure, an important factor is breast density. Women with types C and D breast density according to American College of Radiology (ACR) classification have 4–6-fold increased risk of cancer compared to women with type A breast density. With this type of density, the effectiveness of diagnostic mammography (MG) is significantly decreased. Today, automated breast 3D ultrasound can be considered as an additional screening method in women with breast structure types C and D according to ACR.Objective: to perform a comparative analysis of the diagnostic efficacy of 2D and 3D ultrasound in women aged 40 years and older with high breast tissue density.Material and methods. Retro-prospective, observational, single-center study was conducted. From February 2019 to May 2023, 1283 patients aged 40 years and older were examined. The patients were divided into two groups. In group A, women underwent 2D ultrasound and MG. In group B, additionally to these methods, 3D ultrasound was performed. In both groups, the results were evaluated according to Breast Imaging-Reporting and Data System (BI-RADS). Based on the obtained data, the following indicators were determined: positive (PPV) and negative (NPV) predictive values, sensitivity, specificity and accuracy of all methods. For 2D and 3D ultrasound, the predictive model areas under curve (AUC) of receiver operating characteristic (ROC) were calculated.Results. MG method showed PPV 0.89, NPV 0.93, sensitivity 0.53, specificity 0.99, and balanced accuracy 0.76. Indicators for 2D ultrasound demonstrated PPV 0.8, NPV 0.98, sensitivity 0.9, specificity 0.97, balanced accuracy 0.93, AUC ROC 0.968. The results for 3D ultrasound were as follows: PPV 0.97, NPV 0.97, sensitivity 0.9, specificity 0.99, balanced accuracy 0.94, AUC ROC 0.98.Conclusion. The diagnostic efficiency of breast automated 3D ultrasound in patients aged 40 years and older is comparable to 2D ultrasound in terms of sensitivity, and it’s better in terms of accuracy, specificity. The prognostic model of 3D ultrasound is also better compared to 2D ultrasound.

A comparison of 2D and 3D with the use of HDlive mode imaging in the diagnosis of endometrial polyps in infertility

Objective: to compare 2D ultrasound and 3D with HDlive mode ultrasound in the diagnosis of endometrial polyps in infertility.Material and methods. The retrospective cohort study included 116 women aged 29 to 43 years (mean age 36.9 ± 3.78) with infertility who were observed at the Nova Clinic Center for Reproduction and Genetics from January 2021 to June 2024. 2D and 3D ultrasounds were performed in all patients. The final conclusion on the presence or absence of pathology was based on the results of the 3D study with HDlive mode. The histological verification of polyps was carried out after hysteroscopy.Results. Hysteroscopy revealed no signs of pathology in 5 (4.3%) patients; moreover, the results of 2D imaging were also negative, and the results of 3D imaging were positive. In other 111 cases (95.7%), the diagnosis of a polyp was confirmed on hysteroscopy. Among them, no signs of pathology were found on 2D ultrasound in 19 (16.4%) patients. According to the obtained results, the use of 3D imaging with HDlive mode leads to overdiagnosis and false positive results with a chance of 4.5%. On the contrary, 2D imaging leads to underdiagnosis and false negative results with a chance of 19.6%, which is statistically significantly higher than the chance of a false positive result using the 3D method (p = 0.008). Thus, the chance of a false result using the 2D mode is 4.4 [1.57; 12.09] times higher than using the 3D mode.Conclusions. The study demonstrated a higher accuracy of the 3D ultrasound compared to 2D ultrasound in diagnosing endometrial polyps.

Comparing the Diagnostic Efficacy of 3D Ultrasound and MRI in the Classification of Müllerian Anomalies.

Müllerian anomalies significantly impact female reproductive health. This study aims to compare the diagnostic efficacy of three-dimensional ultrasound (3D-US) and magnetic resonance imaging (MRI) in detecting and classifying these anomalies. A retrospective analysis of 150 patients with Müllerian anomalies was conducted at Saveetha Medical College and Hospital from March 2018 to March 2024. MRI and 3D-US examinations were performed and analyzed independently by two radiologists. Anomalies were classified according to European Society of Human Reproduction and Embryology (ESHRE)/European Society for Gynaecological Endoscopy (ESGE) and American Society for Reproductive Medicine (ASRM) guidelines. The septate uterus was the most prevalent anomaly, observed in 53 patients (35.3%). MRI demonstrated superior diagnostic accuracy (AUC 0.92) compared to 3D-US (AUC 0.88). Significant associations were found between presenting symptoms and specific anomaly types (p < 0.05). Inter-rater reliability between the two radiologists, with respect to classification of anomalies, was high (Cohen's kappa 0.85). MRI's superior soft-tissue contrast and multiplanar capabilities make it the gold standard for evaluating complex uterine malformations. 3D-US offers valuable real-time imaging and is particularly effective in assessing septum characteristics. The combined use of MRI and 3D-US enhances diagnostic precision and facilitates tailored management strategies. Integrating MRI and 3D-US in clinical practice improves diagnostic accuracy and treatment planning for Müllerian anomalies, ultimately enhancing patient outcomes.

Robotic Needle Insertion With 2D Ultrasound–3D CT Fusion Guidance

Robotic Needle Insertion With 2D Ultrasound–3D CT Fusion Guidance

Effect of maneuvers, diuresis, and fluid administration on ultrasound-measured liver stiffness after Fontan.

To determine the effect of stress maneuvers/interventions on ultrasound liver stiffness measurements (LSMs) in patients with Fontan circulation and healthy controls. In this prospective, IRB-approved study of 10 patients after Fontan palliation and 10 healthy controls, ultrasound 2D shear-wave elastography LSMs were acquired at baseline and after maximum inspiration, expiration, standing, handgrip, aerobic exercise, i.v. fluid (500mL normal saline) administration, and i.v. furosemide (20mg) administration. Absolute and percent change in LSM were compared between baseline and each maneuver, and then from fluid infusion to after diuresis. Median ages were 25.5 and 26 years in the post-Fontan and control groups (p = 0.796). LSMs after Fontan were higher at baseline (2.6 vs. 1.3m/s) and with all maneuvers compared to controls (all p < 0.001). Changes in LSM with maneuvers, exercise, fluid, or diuresis were not significant when compared to baseline in post-Fontan patients. LSM in controls increased with inspiration (+0.02m/s, 1.6%, p = 0.03), standing (+0.07m/s, 5.5%, p = 0.03), and fluid administration (+0.10m/s, 7.8%, p = 0.002), and decreased 60 minutes after diuretic administration (-0.05m/s, -3.9%, p = 0.01) compared to baseline. LSM after diuretic administration significantly decreased when compared to after i.v. fluid administration at 30 minutes (-0.79m/s, -26.5%, p = 0.004) and 60 minutes (-0.78m/s, -26.2%, p = 0.017) for patients after Fontan and controls at 15 minutes (-0.12m/s, -8.70%, p = 0.002), 30 minutes (-0.15m/s, -10.9%, p = 0.003), and 60 minutes (-0.1m/s, -10.9%, p = 0.005). LSM after Fontan is higher with more variability compared to controls. Diuresis is associated with significantly decreased liver stiffness in both patients after Fontan and controls, with the suggestion of a greater effect in Fontan patients.

Improved ground truth annotation by multimodal image registration from 3D ultrasound to histopathology for resected tongue carcinoma.

This study's objectives are (1) to investigate the registration accuracy from intraoperative ultrasound (US) to histopathological images, (2) to assess the agreement and correlation between measurements in registered 3D US and histopathology, and (3) to train a nnUNet model for automatic segmentation of 3D US volumes of resected tongue specimens. Ten 3D US volumes were acquired, including the corresponding digitalized histopathological images (n = 29). Based on corresponding landmarks, the registrations between 3D US and histopathology images were calculated and evaluated using the target registration error (TRE). Tumor thickness and resection margins were measured based on three annotations: (1) manual histopathological tumor annotation (HTA), manual 3D US tumor annotation, and (2) the HTA registered in the 3D US. The agreement and correlation were computed between the measurements based on the HTA and those based on the manual US and registered HTA in US. A deep-learning model with nnUNet was trained on 151 3D US volumes. Segmentation metrics quantified the model's performance. The median TRE was 0.42mm. The smallest mean difference was between registered HTA in US and histopathology with 2.16mm (95% CI - 1.31; 5.63) and a correlation of 0.924 (p < 0.001). The nnUNet predicted the tumor with a Dice similarity coefficient of 0.621, an average surface distance of 1.15mm, and a Hausdorff distance of 3.70mm. Multimodal image registration enabled the HTA's registration in the US images and improved the agreement and correlation between the modalities. In the future, this could be used to annotate ground truth labels accurately.

Strengthening Cu-containing high entropy alloys through ultrasonic solidification constructed heterostructures

The solidification process of FeCoNiCu1.5Al0.2 high-entropy alloy (HEA) with two FCC phases was modulated by three-dimensional (3D) ultrasounds with 20 kHz frequency and 22 μm amplitude. The statically solidified alloy was composed of a primary γ1 phase growing into coarse dendrites and a Cu-rich γ2 phase dispersed in interdendritic spacings. Once 3D ultrasounds were applied, the primary γ1 phase was refined into small equiaxed grains and the secondary γ2 phase was distributed around their grain boundaries. Based on the estimation of local sound pressure and undercooling, as well as acoustic spectra examination, it is concluded that transient cavitation was the dominant reason for the formation of tiny equiaxed γ1 phase by remarkably increasing local nucleation rate, which also promoted the generation of connected γ2 phase together with acoustic streaming effect. The yield strength, ultimate strength and total elongation for ultrasonically solidified alloy sample were simultaneously enhanced by 73 %, 54 % and 13 %, which were up to 605 MPa, 845 MPa and 35 % respectively. According to LUR tests and dislocation characterization, both hetero-deformation induced (HDI) strengthening and grain refinement strengthening contributed to the increase of yield strength, while the former mainly enhanced ultimate strength and ductility synergistically. This indicates that 3D ultrasonic solidification provides an effective approach to overcoming the strength-ductility trade-off for Cu-containing HEAs.

Analysis of the Clinical Value of Two-Dimensional Plus Four-Dimensional Ultrasound in the Diagnosis of Fetal Facial Anomalies

Objective: To explore and analyze the clinical value of two-dimensional plus four-dimensional ultrasound in diagnosing fetal facial anomalies. Methods: To review and analyze the basic data of 50 fetuses with facet anomalies delivered in Maternal and Child Health Hospital of Jiangyan District from January 2017 to January 2023, and to analyze and compare the two-dimensional (2D) diagnostic results of all the fetuses (2D group), and the combined 2D and four-dimensional (4D) diagnostic results (combined group). Results: Taking the delivery results as the gold standard, 39 fetuses with facial anomalies were diagnosed in the 2D group, and 48 fetuses with facial anomalies were diagnosed in the combined group, which showed that the diagnostic compliance rate of the 2D group was significantly lower than that of the combined group, and the difference of P &lt; 0.05 was statistically significant. The sensitivity and accuracy of the diagnostic efficiency of the combined group were significantly higher than that of the 2D group, and the difference was statistically significant at P &lt; 0.05; the specificity of the diagnostic efficiency of the combined group and the 2D group was compared, and the difference was not statistically significant at (P &gt; 0.05). Conclusion: 2D plus 4D ultrasounds are more accurate in diagnosing fetal facial anomalies, and the combined diagnosis is more clinically significant, so it is recommended to be widely used and promoted.

Prediction of Preoperative Cesarean Scar Dehiscence by Using 2D Ultrasound in Pregnant Women with Previous Cesarean Section

Prediction of Preoperative Cesarean Scar Dehiscence by Using 2D Ultrasound in Pregnant Women with Previous Cesarean Section

Automatic bony structure segmentation and curvature estimation on ultrasound cervical spine images - a feasibility study

Abstract The loss of cervical lordosis is a common degenerative disorder known to be associated with abnormal spinal alignment. In recent years, ultrasound (US) imaging has been widely applied in the assessment of spine deformity and has shown promising results. The objectives of this study are to automatically segment bony structures from the 3D US cervical spine image volume and to assess the cervical lordosis on the key sagittal frames. In this study, a portable ultrasound imaging system was applied to acquire cervical spine image volume. The nnU-Net was trained on to segment bony structures on the transverse images and validated by 5-fold-cross-validation. The volume data were reconstructed from the segmented image series. An energy function indicating intensity levels and integrity of bony structures was designed to extract the proxy key sagittal frames on both left and right sides for the cervical curve measurement. The mean absolute difference (MAD), standard deviation (SD) and correlation between the spine curvatures of the left and right sides were calculated for quantitative evaluation of the proposed method. The DSC value of the nnU-Net model in segmenting ROI was 0.973. For the measurement of 22 lamina curve angles, the MAD±SD and correlation between the left and right sides of the cervical spine were 3.591±3.432° and 0.926, respectively. The results indicate that our method has a high accuracy and reliability in the automatic segmentation of the cervical spine and shows the potential of diagnosing the loss of cervical lordosis using the 3D ultrasound imaging technique.

DC-UNet: Looking for follicles in the ovarian ultrasound images

The auspicious initiation of human reproduction starts by releasing the ovum through ovulation within the ovary. Ceaseless monitoring of the female reproductive organs has now become essential for combating fertility-related issues and for successful assisted reproduction. Cases of infertility and demands for assisted reproduction in our modern liberated society are rapidly increasing. External or Transvaginal ultrasound imaging of the ovary provides us with vital information about the number, size, and position of the follicles in the ovary and their cumulative response to biological stimuli. Manual screening of thousands of USG images having lacs of follicles is an extremely strenuous job and prone to humane error. This paper propounded a new deep-learning architecture named Double Contraction-UNet (DC-UNet) which makes follicle segmentation fully automatic. This model restructured the U-Net architecture by introducing two contracting paths to segment the follicular object with higher accuracy. The model was trained and tested on approximately forty two thousand annotated ovarian 2D ultrasonography images extracted from USOVA3D Training Set 1. The proposed model outperforms the other U-Net-based state-of-the-art models when trained and tested on the same dataset. The proposed model has achieved an accuracy rate of 97.82%, a precision rate of 97.54%, a Recall value of 94.34%, an F1 Score of 95.91%, a Dice Score of 0.76, and a Jaccard Similarity Index of 0.59.

Neural implicit surface reconstruction of freehand 3D ultrasound volume with geometric constraints

Three-dimensional (3D) freehand ultrasound (US) is a widely used imaging modality that allows non-invasive imaging of medical anatomy without radiation exposure. Surface reconstruction of US volume is vital to acquire the accurate anatomical structures needed for modeling, registration, and visualization. However, traditional methods cannot produce a high-quality surface due to image noise. Despite improvements in smoothness, continuity, and resolution from deep learning approaches, research on surface reconstruction in freehand 3D US is still limited. This study introduces FUNSR, a self-supervised neural implicit surface reconstruction method to learn signed distance functions (SDFs) from US volumes. In particular, FUNSR iteratively learns the SDFs by moving the 3D queries sampled around volumetric point clouds to approximate the surface, guided by two novel geometric constraints: sign consistency constraint and on-surface constraint with adversarial learning. Our approach has been thoroughly evaluated across four datasets to demonstrate its adaptability to various anatomical structures, including a hip phantom dataset, two vascular datasets and one publicly available prostate dataset. We also show that smooth and continuous representations greatly enhance the visual appearance of US data. Furthermore, we highlight the potential of our method to improve segmentation performance, and its robustness to noise distribution and motion perturbation.

"A Picture Paints a Thousand Words"-A Systematic Review of the Ethical Issues of Prenatal Ultrasound.

Prenatal ultrasound is a non-invasive diagnostic examination. Despite the recognized diagnostic value, this technology raises complex ethical questions. The aim of this study is to provide a comprehensive analysis that coherently maps the ethical challenges raised by prenatal ultrasound examination, both 2D and 3D. We performed a systematic literature review. Six databases were systematically searched. The results highlight how concerns related to beneficence, informed consent, and autonomy are mainly related to routine use of prenatal ultrasound in the clinical context, while considerations linked to overmedicalization of pregnancy, discrimination, and fetal ontology were often reported in relation to the impact ultrasound is having on medicine and society. Ethical issues in the context of pre-abortion ultrasound, obstetric practices in low-income settings, and keepsake ultrasound imaging were also greatly discussed. Since prenatal ultrasound practices critically impact pregnant people's autonomy and their role within pregnancy, we conclude that information providing strategies should be developed to appropriately inform pregnant people about the nature, purpose, risks, and choices revolving around prenatal ultrasound. In addition, as it is becoming increasingly difficult to separate the social and clinical dimensions of prenatal ultrasound, future research should focus on examining if and how such dimensions should be reconciled.

Reliability and accuracy of scoliotic parameters on using a wireless handheld 3D ultrasound for children with adolescent idiopathic scoliosis: a pilot study.

To report the accuracy and reliability of Cobb angle (CA), axial vertebral rotation (AVR), kyphotic and lordotic angles (KA and LA) measurements on using a new 3D ultrasound (US) system. Forty participants (34F, 6M, aged 14.0 ± 2.3 years) were recruited. The first 20 participants were scanned by the validated US system and the new US system. The other 20 participants were scanned with the new US system only. Two raters (R1 and R2) performed the measurements: R1 has 10 years of experience in radiology but is new in ultrasound scoliosis, while R2 has 30 years of scoliosis experience. All US images were measured twice by R1, and once by R2. Forty posteroanterior and 30 lateral standing radiographs were obtained and measured once by R1. Statistical analysis consisted of mean absolute difference (MAD), intraclass correlation coefficient (ICC(2,1)), and Bland-Altman plots. R1 showed excellent intra-rater and inter-rater reliability for US measurements with ICCs(2,1) ≥ 0.91. The inter-method reliability was good between the two US systems for all parameters with ICCs(2,1) ≥ 0.85 and maximum MAD of 3.4°. The new US showed good reliability and accuracy compared to radiographs for CA, AVR and KA with ICCs(2,1) ≥ 0.81 and maximum MAD of 5.8°, but poor results for LA with ICCs(2,1) of 0.27-0.35 and MADs of 14.0°-15.4°. The new 3D US system showed good reliability and accuracy for CA, AVR and KA measurements, but a large measurement discrepancy on LA. A new measurement method for US LA may need to investigate.

Three-dimensional trans-rectal and trans-abdominal ultrasound image fusion for the guidance of gynecologic brachytherapy procedures: a proof of concept study

High dose-rate brachytherapy is a treatment technique for gynecologic cancers where intracavitary applicators are placed within the patient’s pelvic cavity. To ensure accurate radiation delivery, localization of the applicator at the time of insertion is vital. This study proposes a novel method for acquiring, registering, and fusing three-dimensional (3D) trans-abdominal and 3D trans-rectal ultrasound (US) images for visualization of the pelvic anatomy and applicators during gynecologic brachytherapy. The workflow was validated using custom multi-modal pelvic phantoms and demonstrated during two patient procedures. Experiments were performed for three types of intracavitary applicators: ring-and-tandem, ring-and-tandem with interstitial needles, and tandem-and-ovoids. Fused 3D US images were registered to magnetic resonance (MR) and computed tomography (CT) images for validation. The target registration error (TRE) and fiducial localization error (FLE) were calculated to quantify the accuracy of our fusion technique. For both phantom and patient images, TRE and FLE across all modality registrations (3D US versus MR or CT) resulted in mean ± standard deviation of 4.01 ± 1.01 mm and 0.43 ± 0.24 mm, respectively. This work indicates proof of concept for conducting further clinical studies leveraging 3D US imaging as an accurate, accessible alternative to advanced modalities for localizing brachytherapy applicators.

Prenatal Diagnosis of Bilateral Meromelia Coexisting With Duodenal Atresia: Case Report of a Rare Anomalous Combination With Three-Dimensional Sonography

A rare case of bilateral fetal meromelia with duodenal atresia (DA) was diagnosed on three-dimensional (3D) sonography. A 32-year-old G3P2002 with a large for date uterus, was reviewed at 26 weeks’ gestation. The 3D sonogram confirmed the presence of the humerus, olecranon process, and only the proximal third of the ulna bone, bilaterally. The distal ulna, radius, metacarpals, and phalanges were absent on both upper limbs. The bones of the lower limbs were present and appropriate for gestational age. Further evaluation revealed the “double bubble” sign, which is characteristic of DA within the fetal abdomen. The patient was induced 2 weeks later, due to intrauterine fetal demise. The suspected fetal anomalies were confirmed at birth. A high index of suspicion and a detailed sonographic evaluation are essential for detecting rare fetal anomalies, such as meromelia.

Six-Degree-of-Freedom Freehand 3D Ultrasound: A Low-Cost Computer Vision-Based Approach for Orthopedic Applications.

In orthopedics, X-rays and computed tomography (CT) scans play pivotal roles in diagnosing and treating bone pathologies. Machine bulkiness and the emission of ionizing radiation remain the main problems associated with these techniques. The accessibility and low risks related to ultrasound handling make it a popular 2D imaging method. Indeed, 3D ultrasound assembles 2D slices into a 3D volume. This study aimed to implement a probe-tracking method for 6 DoF 3D ultrasound. The proposed method involves a dodecahedron with ArUco markers attached, enabling computer vision tracking of the ultrasound probe's position and orientation. The algorithm focuses on the data acquisition phase but covers the basic reconstruction required for data generation and analysis. In the best case, the analysis revealed an average error norm of 2.858 mm with a standard deviation norm of 5.534 mm compared to an infrared optical tracking system used as a reference. This study demonstrates the feasibility of performing volumetric imaging without ionizing radiation or bulky systems. This marker-based approach shows promise for enhancing orthopedic imaging, providing a more accessible imaging modality for helping clinicians to diagnose pathologies regarding complex joints, such as the shoulder, replacing standard infrared tracking systems known to suffer from marker occlusion problems.