Ultrasonic Imaging最新文献

We have developed a 3-D acoustic radiation force impulse (ARFI) prostate imaging system to identify regions suspicious for cancer and guide a targeted prostate biopsy in a single visit. The system uses a side-fire transrectal probe and an automated rotation stage to acquire ARFI and B-mode image volumes, combined with 3-D visualization and targeting software to enable biopsy target identification and guide a transperineal (TP) biopsy. The system was tested in the first clinical trial of its kind, with subjects serially undergoing ARFI-guided targeted TP biopsy, multiparametric magnetic resonance imaging (mpMRI)-ultrasound fusion TP biopsy, and systematic sampling TP biopsy. The findings indicate that the ARFI system is feasible for guiding a targeted biopsy. For lower-grade cancer (grade groups [GG] 1-2), ARFI underperformed mpMRI and systematic sampling, detecting cancer in 54% of GG 2 subjects. However, ARFI performance improved with increasing cancer grade; for higher-grade cancer (GG 3-5), ARFI performed comparably to the other biopsy approaches, and detected cancer in all GG 4 and 5 subjects. The findings also suggest the benefit of using 2-D ARFI imaging to confirm target location during live B-mode imaging, which could improve existing ultrasonic fusion biopsy workflows. This study is registered with ClinicalTrials.gov as NCT04607135.

This study aims to establish and validate an ultrasound radiomics nomogram for preoperative prediction of central lymph node metastasis in papillary thyroid microcarcinoma (PTMC) before operation. A retrospective analysis conducted on ultrasonic images and clinical features derived from 288 PTMC patients, who were divided into training cohorts (n = 201) and validating cohorts (n = 87) in a ratio of 7:3 base on the principle of random allocation. Radiomics features were extracted from the PTMC patients after ultrasonic examination, followed by dimension reduction and characteristic selection to construct the radiomics score (Radscore) using LASSO regression analysis. Subsequently, the models, ultrasound features plus clinical features (US-Clin), radiomics score model, and combined model of clinical features plus ultrasound features and Radscore (Combined-model) were built through multi-factor logistic regression analysis. After that, the nomograms were developed for visualization and presentation of these models. The discriminative power, calibration and clinical utility of the nomogram models were evaluated in the training and validating cohorts. The Radscore model comprised 12 carefully selected features. The independent risk factors for conventional ultrasound features and clinical features of PTMC in predicting CLNM included age <45 years, tumor envelope invasion, male gender and presence of microcalcifications, while the enhanced ultrasound features risk factor was extrathyroidal expansion. The combined model showed good performance in predicting PTMC CLNM, with AUCs of 0.921 and 0.889 in the training and validating cohorts, respectively. And DCA based on the prediction model showed good clinical utility. The nomogram developed based on preoperative clinical data, ultrasound features, and Radscore of PTMC patients can more accurately predict central lymph node metastasis (CLNM) in PTMC patients. However, it needs to be validated for clinical applicability in multicenter studies with larger sample sizes and combined with genomic mutation analyses of the tumors.

Imaging depth remains a restriction for Synthetic Aperture (SA) approaches, even though SA techniques have been shown to overcome some of the drawbacks of Conventional Focused Beamforming (CFB) technique. This limitation is attributed to lesser energy per transmit in SA techniques compared to that of CFB technique. Therefore, in this paper, a systematic investigation is done to evaluate the improvement in imaging depth and image quality of B-mode ultrasound images in the case of SA technique using PZT transducer by boosting the input voltage to the transducer, while measuring the acoustic exposure parameters recommended in international standards. Note-while acoustic exposure parameters like Mechanical and Thermal index (MI and TI, respectively) are well-studied and reported for CFB techniques, the same is not the case with novel SA techniques. For analysis, the image quality metrics of Contrast Ratio (CR), Contrast to Noise Ratio (CNR) and generalized Contrast to Noise Ratio (gCNR) are employed for the SA techniques of Synthetic Transmit Aperture (STA) and Diverging Beam Synthetic Aperture Technique (DB-SAT). The results show that, when the input voltage is increased from 45 to 70 V in PZT transducer, the following improvements in image quality parameters were observed: CR by 15.6% and 21.25%, CNR by 21.39% and 36.23% and gCNR by 14.1% and 21.5% for STA and DB-SAT techniques, respectively. Results also suggest that the considerable imaging depth improvement is achieved for the incremental input voltage till 60 V, with the highest of 7.5% depth improvement at 60 V, above which the tradeoff between the gain in imaging depth and acoustic safety index becomes critical to consider. Recently, transducers having lead magnesium nitrate lead titanate (PMN-PT) piezoelectric single crystals have shown to produce ultrasound images with higher image quality at greater depths, irrespective of the transmit schemes. The same concept of relatively higher output transmitting energy by cost expensive PMN-PT single crystal transducers for the same applied voltage, compared to the traditional lead zirconate titanate (PZT) transducers, explains the enhanced imaging depth. This study is probably the first one that reports the comparison between PMN-PT and PZT transducer, not only in terms of imaging depth but also reporting them in the context of acoustic exposure safety limits in terms of MI and TI. The findings of this study may help system designers to minimize the trade-off between cost and image quality.

Polymer microbubbles have garnered broad interest as potential theranostic agents. However, the capabilities of polymer MBs can be greatly enhanced, particularly regarding the imaging performance and functional versatility of the platform. This study investigates integrating fluorescent carbon nanodots within polylactic acid (PLA) microbubbles. First, the formulations are characterized by their size, microbubble counts, zeta potential, and resonance frequency. Then, the fluorescence capabilities, nanoparticle loading, and acoustic capabilities are examined. Unmodified (U-), carboxylated (C-), and aminated graphene quantum dots (A-GQDs) were separately suspended and synthesized at a 2% w/w ratio with PLA in the organic phase of the water/oil/water double emulsion process. The new microbubbles were characterized using an AccuSizer, Zetasizer, scanning electron microscopy, fluorescence microscopy and fluorimetry, a custom-built acoustic setup, and clinical ultrasound. The GQD microbubbles were sized between 1.4 and 1.9 µm (U = 1.90, C = 1.44, A = 1.72, Unloaded = 2.02 µm). The U-GQD microbubble exhibited a higher bubble concentration/mg PLA (p < .05) and the A-GQD microbubbles exhibited the greatest shift in zeta potential. Electron microscopy revealed smooth surfaces and a spherical shape, showing that the nanoparticle addition was not deleterious. The A-GQD microbubbles were specifically detectable using DAPI-filtering with fluorescence microscopy and had the highest TRITC-filtered fluorescence. The C-GQD microbubbles had the highest loading efficiency at 59.4% (p < .05), and the lowest max acoustic enhancement at 5 MHz (U = 19.8, C = 17.6, A = 18.9, Unloaded = 18.5 dB; p < .05). Additionally, all microbubbles were visible and susceptible to inertial cavitation utilizing clinical ultrasound. The A-GQDs showed promise toward improving the theranostic capabilities of the microbubble platform. They have imbued the most advantageous fluorescence capability and slightly improved backscatter enhancement while retaining all the necessary capabilities of an ultrasound contrast agent. Future studies will investigate the coloading potential of A-GQDs and drug within microbubbles.

Time-resolved three-dimensional ultrasound (3D + t US) is a promising imaging modality for monitoring abdominal aortic aneurysms (AAAs), providing their 3D geometry and motion. The lateral contrast of US is poor, a well-documented drawback which multi-perspective (MP) imaging could resolve. This study aims to show the feasibility of in vivo multi-perspective 3D + t ultrasound imaging of AAAs for improving the image contrast and displacement accuracy. To achieve this, single-perspective (SP) aortic ultrasound images from three different angles were spatiotemporally registered and fused, and the displacements were compounded. The fused MP had a significantly higher wall-lumen contrast than the SP images, for both patients and volunteers (P < .001). MP radial displacements patterns are smoother than SP patterns in 67% of volunteers and 92% of patients. The MP images from three angles have a decreased tracking error (P < .001 for all participants), and an improved SNR_e compared to two out of three SP images (P < .05). This study has shown the added value of MP 3D + t US, improving both image contrast and displacement accuracy in AAA imaging. This is a step toward using multiple or large transducers in the clinic to capture the 3D geometry and strain more accurately, for patient-specific characterization of AAAs.

To investigate the efficiency of contrast-enhanced ultrasound (CEUS) features, particularly ring-enhancement patterns, in the differential diagnosis of thyroid nodules. 302 nodules with CEUS ring-enhancement were retrospectively enrolled, including 135 benign and 167 malignant ones. The ring-enhancement patterns were classified into regular and irregular hyper- or hypo-ring enhancement. Comparative analyses of ultrasound (US) and CEUS features between benign and malignant nodules were performed. The diagnostic performances of the ring-enhancement patterns and Chinese Thyroid Imaging Reporting and Data System (C-TIRADS) were compared in nodules with different sizes. Irregular hypo-ring enhancement was much more common in malignancies than that in benign ones, and it was an independent predictor for thyroid malignant nodules. With irregular hypo-ring enhancement as the diagnostic criteria for malignant nodules, the specificity was higher than that of C-TIRADS (85.2% vs. 75.6%, p = .037) while the AUC was comparable (0.845 vs. 0.803, p = .136) in all nodules. When the nodule size was taken into account, the specificity and AUC were both significantly higher than those of C-TIRADS (92.8% vs. 81.1%, p = .021; 0.907 vs. 0.823, p = .026) in nodules ≥10 mm, which can decrease the unnecessary FNA rate. Irregular hypo-ring enhancement was a valuable CEUS feature for the differential diagnosis of thyroid nodules, especially in nodules ≥10 mm.

To formulate a predictive model for assessing Ki-67 expression in breast cancer by integrating pre-treatment ultrasound features with non-morphological magnetic resonance imaging (MRI) parameters, encompassing functional and hemodynamic indicators. A retrospective study was conducted on 167 patients. All patients underwent a breast mass biopsy for histopathological and Ki-67 analysis prior to neoadjuvant chemotherapy (NAC) treatment. Additionally, all patients underwent ultrasonography and MRI examinations prior to the biopsy. The recorded variables were Ki-67, apparent diffusion coefficient (ADC) values, Max Slope, time to peak (TTP), signal enhancement ratio (SER), early enhancement rate (EER), time-signal intensity curve (TIC), tumor maximum diameter, tumor margins and boundaries, aspect ratio, microcalcification, color Doppler flow imaging grading, resistance index (RI), and axillary lymph node metastasis. Statistical analysis was performed using the R software package. Normally distributed continuous data are presented as mean ± standard deviation (SD), skewed continuous data as median, and categorical variables as frequency or percentage. The dataset was randomly divided into a modeling group and a validation group following a 7:3 ratio, employing a predetermined random seed. The selection of variables was conducted using the random forest algorithm. Specifically, in the initial analysis, we trained a random forest model using all available variables. By evaluating the Gini importance scores of each variable, we identified those that contributed the most to predicting Ki-67 expression. The predictive model for Ki-67 expression was constructed using selected variables: Maximum Diameter, ADC value, SER value, Max Slope value, TTP value, and EER value. Within the validation group, the evaluation metrics demonstrated an Area under the curve of 0.961 with a 95% confidence interval ranging from 0.865 to 0.995. The model achieved a kappa score of 1.00, precision of 0.949, recall of 1, an F1 score of 0.974, sensitivity of 100%, specificity of 85.71%, a positive predictive value of 94.87%, and a negative predictive value of 100%. The combination of non-morphological MRI parameters and pre-treatment ultrasound features in a breast cancer prediction model powered by RF machine learning demonstrated favorable clinical outcomes and improved diagnostic performance.

Ultrasound imaging for bone is a difficult task in the field of medical ultrasound. Compared with other phase array techniques, the synthetic aperture (SA) has a better lateral resolution but a limited imaging depth due to the limited ultrasonic energy emitted by the single emitter in each transmission. In contrast, the virtual source (VS) synthetic aperture allows a simultaneous multi-element emission and could provide a higher ultrasonic incident energy in each transmission. Therefore, the VS might achieve a high imaging quality at a deeper depth for bone imaging than the traditional SA. In this study, we proposed the virtual source phase shift migration (VS-PSM) method to achieve ultrasonic imaging of the deeper bone defect featured in the multilayer structure. The proposed VS-PSM method was validated using standard soft tissue phantom and printed bone phantom with artificial defects. The image quality was evaluated in terms of contrast-to-noise ratios (CNR) and amplitudes of scatters and defects at different imaging depths. The results showed that the VS-PSM method could achieve a high imaging quality of the soft tissues with a significant improvement in the scattering amplitude and without a significant sacrifice of the lateral and axial resolution. The PSM was superior to the DAS in suppressing the background noise in the images. Compared with the traditional SA-PSM, the VS-PSM method could image deeper bone defects at different ultrasonic frequencies, with an average improvement of 50% in CNR. In conclusion, this study demonstrated that the proposed VS-PSM method could image deeper bone defects and might help the diagnosis of bone disease using ultrasonic imaging.

Sm-doped Pb(Mg_1/3Nb_2/3)O₃-0.28PbTiO₃ (PMN-0.28PT) ceramic has been reported to exhibit very large piezoelectric response (d₃₃~1300 pC/N) that can be comparable with PMN-0.30PT single crystal. Based on the Sm-doped PMN-0.28PT ceramics, a high frequency ultrasound transducer with the center frequency above 30 MHz has been designed and fabricated for intravascular ultrasound imaging, and the performance of the transducer was investigated via ultrasound pulse-echo tests. Further, for a porcine vessel wall, the 2D and 3D ultrasound images were constructed using signal acquisition and processing from the fabricated high-frequency transducer. The obtained details of the vessel wall by the IVUS transducer indicate that Sm-doped PMN-0.28PT ceramic is a promising candidate for high frequency transducers.

To explore the predictive value of the nomogram model based on multimodal ultrasound features for benign and malignant thyroid nodules of C-TIRADS category 4. A retrospective analysis was conducted on the general conditions and ultrasound features of patients who underwent thyroid ultrasound examination and fine needle aspiration biopsy (FNA) or thyroidectomy at the Affiliated Hospital of Zunyi Medical University from April 2020 to April 2023. Predictive signs for benign and malignant nodules of thyroid C-TIRADS category 4 were screened through LASSO regression and multivariate logistic regression analysis to construct a nomogram prediction model. The predictive efficiency and accuracy of the model were assessed through ROC curves and calibration curves. Seven independent risk factors in the predictive model for benign and malignant thyroid nodules of C-TIRADS category 4 were growth pattern, morphology, microcalcifications, SR, arterial phase enhancement intensity, initial perfusion time, and PE [%]. Based on these features, the area under the curve (AUC) of the constructed prediction model was 0.971 (p ＜ .001, 95% CI: 0.952-0.989), with a prediction accuracy of 93.1%. Internal validation showed that the nomogram calibration curve was consistent with reality, and the decision curve analysis indicated that the model has high clinical application value. The nomogram prediction model constructed based on the multimodal ultrasound features of thyroid nodules of C-TIRADS category 4 has high clinical application value.