Conventional US Imaging Research Articles

Deep learning predicts cervical lymph node metastasis in clinically node-negative papillary thyroid carcinoma

ObjectivesPrecise determination of cervical lymph node metastasis (CLNM) involvement in patients with early-stage thyroid cancer is fairly significant for identifying appropriate cervical treatment options. However, it is almost impossible to directly judge lymph node metastasis based on the imaging information of early-stage thyroid cancer patients with clinically negative lymph nodes.MethodsPreoperative US images (BMUS and CDFI) of 1031 clinically node negative PTC patients definitively diagnosed on pathology from two independent hospitals were divided into training set, validation set, internal test set, and external test set. An ensemble deep learning model based on ResNet-50 was built integrating clinical variables, BMUS, and CDFI images using a bagging classifier to predict metastasis of CLN. The final ensemble model performance was compared with expert interpretation.ResultsThe ensemble deep convolutional neural network (DCNN) achieved high performance in predicting CLNM in the test sets examined, with area under the curve values of 0.86 (95% CI 0.78–0.94) for the internal test set and 0.77 (95% CI 0.68–0.87) for the external test set. Compared to all radiologists averaged, the ensemble DCNN model also exhibited improved performance in making predictions. For the external validation set, accuracy was 0.72 versus 0.59 (p = 0.074), sensitivity was 0.75 versus 0.58 (p = 0.039), and specificity was 0.69 versus 0.60 (p = 0.078).ConclusionsDeep learning can non-invasive predict CLNM for clinically node-negative PTC using conventional US imaging of thyroid cancer nodules and clinical variables in a multi-institutional dataset with superior accuracy, sensitivity, and specificity comparable to experts.Critical relevance statementDeep learning efficiently predicts CLNM for clinically node-negative PTC based on US images and clinical variables in an advantageous manner.Key points• A deep learning-based ensemble algorithm for predicting CLNM in PTC was developed.• Ultrasound AI analysis combined with clinical data has advantages in predicting CLNM.• Compared to all experts averaged, the DCNN model achieved higher test performance.Graphical

Using US Twinkling Artifact to Identify Breast Biopsy Markers: Brief Report.

Breast biopsy markers play an essential role in the surgical management of patients with clinically node-positive breast cancer. Marking a pathology-proven lymph node ensures accurate imaging assessment of response to neoadjuvant systemic therapy and decreased false-negative rates in sentinel lymph node biopsy. There is a clinically unmet need to make breast biopsy markers, particularly in the axilla, more sonographically visible or identifiable for preoperative localization purposes. Previously described color Doppler US twinkling artifact of some breast biopsy markers in in vitro gel phantoms and in ex vivo cadaveric breasts suggests that twinkling of such markers can be leveraged for improved in vivo detection. In this retrospective case series of eight female patients (mean age, 58.6 years ± 12.3 [SD]), conventional B-mode US imaging failed to identify the biopsy marker associated with a surgical target in the breast or in an axillary lymph node. However, in each patient, the marker was successfully identified with the help of color Doppler US twinkling. Keywords: Breast, Ultrasound, Color Doppler US, Lymphatic, Artifacts, Biopsy Marker Published under a CC BY 4.0 license.

Contrast-Enhanced Ultrasound Imaging: Novel Method for the Evaluation of Chronic Alcohol-Induced Testicular Damage

The goals of this study were to determine whether contrast-enhanced ultrasound (CEUS) imaging could be used for assessment of chronic alcohol-induced testicular damage (CAITD) and to explore the relationships between the laboratory and pathological findings of CAITD and the quantitative parameters of CEUS. Thirty-six rabbits were randomly divided into a chronic ethanol exposure (CEE) group and negative control (NC) group, which were further randomly divided into six groups with equal numbers of rabbits by period of exposure (30 d, 60 d, 90 d). All rabbits underwent conventional US and CEUS imaging at the end of the induction period. Blood and histological specimens were collected for laboratory and pathological examination. The peak intensity (PI) and area under the curve (AUC) for the CEUS parameters decreased as CAITD progressed (p < 0.05). Both PI and AUC were positively correlated with the Johnsen score (r= 0.945 and 0.898, respectively, all p values <0.001) and the mean epithelium thickness of the seminiferous tubule (METST) (r= 0.927 and 0.881, respectively, all p values <0.001) of the testis, and negatively correlated with the serum levels of endothelin-1 (ET-1) (r = -0.940 and -0.899, respectively, all p values <0.001) and nitric oxide (NO) (r = -0.894 and -0.954, respectively, all p values <0.001), as well as the testicular tissue content of malondialdehyde (MDA) (r = -0.894 and -0.945, respectively, all p values <0.001). CEUS imaging can be used for monitoring organ perfusion of the testis to quantify the development of CAITD.

Validation of a three dimensional musculoskeletal ultrasound system for use in hands and wrists

Purpose: The effect of chronic synovitis on the progression of osteoarthritis pathology is a relatively new but supported concept in the fields of rheumatology and hand surgery that has been linked to pain and disability in patients. Currently, the gold standard for diagnosing synovitis in the wrists and hands is a clinical examination and the use of 2 dimensional (2D) musculoskeletal ultrasound imaging (US). Major limitations associated with this method are the lack of quantitative measurement tools available and the fact that physicians have to be able to mentally reconstruct the patient’s 3-dimensional anatomy from the 2-dimensional images provided. These limitations can be overcome by using a 3-dimensional ultrasound (3DUS) system to quantitatively measure the size of synovial hypertrophy, effusions, ganglions and osteophytes as well as having a 3D reconstruction of the patient’s hand. The aim of this work is to develop a 3D ultrasound system for imaging the hand and wrist. This paper reports on the development, geometric, and volumetric validation for wrist/hand 3D ultrasound imaging. Methods: A mechatronic wrist/hand imaging system was designed and created to operate with a conventional 2D US imaging system. The scanning system features a motor which contains a single integrated electromagnetic encoder that records the rotational position of the motor. This motor drives a lead screw which in turn moves the transducer, which is submerged in a water bath, along the linear axis to acquire a series of 2D images. The encoder information provides the software with the position of each 2D ultrasound frame. These conventional diagnostic 2D US images are then reconstructed into a 3D US images from a licensed ultrasound machine. The geometric validation of the system was done using a multi-layered monofilament grid phantom with spacings of 10 mm and the Euclidean distances between the wires were measured. The volumetric validation was conducted using a simulated synovial tissue phantom and the images were analyzed using 3D-Slicer to manually segment individual slices in the 3D image. These slices were then interpolated to construct a 3D segmentation of the phantom. This process was repeated over four days to test the intra-rater reliability of the system. The 3D volumes were compared to those found using magnetic resonance imaging (MRI) and the known volume of the agar phantom. Results: The largest error and variance recorded from the geometric validation measurements was 0.0856± 0.0087mm and was acquired from the reconstruction plane. The remaining linear measurement errors were all < 1%. The error between the mean phantom volume measurements and the known synovium phantom volume was 5.99% and 2.43% for the 3D US device and MRI respectively. Linear regression for volumetric measures revealed an R2 value of 0.4736 with a p-value of 0.20, revealing no significant correlation between the measurements made over the course of 4 days for the 3D US device. The percent difference in the volume measurements from the 3D US device and MRI was 0.814%. Conclusions: A mechatronic 3D ultrasound imaging system was developed for the wrist and hand. Successful geometric and volumetric validation demonstrates feasibility for implementation in a clinical setting. Current work evaluates system ability to accurately and quantitatively classify synovitis in first carpometacarpal joint and distal radial injury patients to investigate the relationship between chronic inflammation and the progression of osteoarthritis in patients.

High Contrast Ultrasonic Method With Multi-Spatiotemporal Compounding for Monitoring Catheter-Based Ultrasound Thermal Therapy: Development and Ex Vivo Evaluations.

Changes in ultrasound backscatter energy (CBE) imaging can monitor thermal therapy. Catheter-based ultrasound (CBUS) can treat deep tumors with precise spatial control of energy deposition and ablation zones, of which CBE estimation can be limited by low contrast and robustness due to small or inconsistent changes in ultrasound data. This study develops a multi-spatiotemporal compounding CBE (MST-CBE) imaging approach for monitoring specific to CBUS thermal therapy. Ex vivo thermal ablations were performed with stereotactic positioning of a 180° directional CBUS applicator, temperature monitoring probes, endorectal US probe, and subsequent lesion sectioning and measurement. Five frames of raw radiofrequency data were acquired throughout in 15s intervals. Using window-by-window estimation methods, absolute and positive components of MST-CBE images at each point were obtained by the compounding ratio of squared envelope data within an increasing spatial size in each short-time window. Compared with conventional US, Nakagami, and CBE imaging, the detection contrast and robustness quantified by tissue-modification-ratio improved by 37.2 ± 4.7 (p < 0.001), 37.5 ± 5.2 (p < 0.001), and 6.4 ± 4.0 dB (p < 0.05) in the MST-CBE imaging, respectively. Correlation coefficient and bias between cross-sectional dimensions of the ablation zones measured in tissue sections and estimated from MST-CBE were up to 0.91 (p < 0.001) and -0.02 mm2, respectively. The MST-CBE approach can monitor the detailed changes within target tissues and effectively characterize the dimensions of the ablation zone during CBUS energy deposition. The MST-CBE approach could be practical for improved accuracy and contrast of monitoring and evaluation for CBUS thermal therapy.

Quantitative Musculoskeletal Ultrasound

Ultrasound (US) imaging plays a crucial role in the assessment of musculoskeletal (MSK) disorders. Several quantitative tools are offered by US systems and add information to conventional US imaging. This article reviews the quantitative US imaging tools currently available in MSK radiology, specifically focusing on the evaluation of elasticity with shear-wave elastography, perfusion with contrast-enhanced US and noncontrast superb microvascular imaging, and bone and muscle mass with quantitative US methods. Some of them are well established and already of clinical value, such as elasticity and contrast-enhanced perfusion assessment in muscles and tendons. MSK radiologists should be aware of the potential of quantitative US tools and take advantage of their use in everyday practice, both for clinical and research purposes.

Qualitative Evaluation of Virtual Touch Imaging Quantification: A Simple and Useful Method in the Diagnosis of Breast Lesions.

ObjectiveTo test the value of qualitative virtual touch imaging quantification (VTIQ) features in differentiating benign from malignant breast lesions.MethodsFrom November 2016 to August 2017, 230 lesions were subjected to conventional US and virtual touch imaging quantification before biopsy. The maximum shear wave velocity (SWVmax) was measured using a standardized method. Qualitative VTIQ features, including the “stiff rim” sign and color pattern classification, were assessed according to a binary classification. The sensitivity, specificity and area under the receiver operating curve (AUC) of Breast Imaging Reporting and Data System (BI-RADS), SWVmax, qualitative VTIQ features, and combined data were compared.ResultsAmong the 230 breast lesions, 150 were benign and 80 were malignant. Compared to the benign lesions, the malignant ones had higher SWVmax values and were more likely to show the “stiff rim” sign and VTIQ pattern 2 (P <0.001 for all). The AUC value was 0.885 for the qualitative VTIQ combination (the presence of the “stiff rim” sign and/or the display of VTIQ pattern 2), similar to that for SWVmax (P=0.472). BI-RADS combined with the qualitative VTIQ combination and with SWVmax yielded similar results, including significantly higher AUC values (P = 0.018 and 0.014, respectively), significantly higher specificities (P<0.001 for both), and nonsignificantly decreased sensitivities (P = 0.249 for both) compared to BI-RADS alone.ConclusionThe dual-category classification of qualitative VTIQ features according to the presence of the “stiff rim” sign and/or the classification of VTIQ pattern 2 is a simple and useful method that may be representative of quantitative VTIQ parameters in the evaluation of breast masses.

Advanced diagnostic imaging and intervention in tendon diseases.

Degenerative tendon pathology represents one of the most frequent and disabling musculoskeletal disorders. Diagnostic radiology plays a fundamental role in the clinical evaluation of tendon pathologies. Moreover, several minimally invasive treatments can be performed under imaging guidance to treat tendon disorders, maximizing the efficacy and reducing procedural complications. In this review article we describe the most relevant diagnostic features of conventional and advanced US and MRI imaging in tendon disorders, along with the main options for image-guided intervention. (www.actabiomedica.it)

Contrast-enhanced ultrasound findings of adult renal cell carcinoma associated with Xp11.2 translocation/TFE3 gene fusion: comparison with clear cell renal cell carcinoma and papillary renal cell carcinoma

BackgroundTo investigate the contrast-enhanced ultrasound (CEUS) findings of renal cell carcinoma (RCC) associated with Xp11.2 translocation/TFE3 gene fusion (Xp11.2/TFE3) in adult patients by comparison with those of clear cell RCC (ccRCC) and papillary RCC (pRCC).MethodsIn total, 110 patients (110 renal masses) who underwent CEUS examinations were enrolled in this study. The cases included 18 Xp11.2/TFE3 RCCs, 60 ccRCCs and 32 pRCCs. All masses were confirmed by operative pathology. The CEUS imaging data of these patients were retrospectively analysed by two readers. The conventional US and CEUS features of Xp11.2/TFE3 RCC were compared with those of ccRCC and pRCC.ResultsThe age of the patients with Xp11.2/TFE3 RCC ranged from 20 to 68 years, with a mean age of 38.3 ± 16.3 years and a slight female predominance. The weighted kappa value that interprets the concordance between the interobserver agreement of the US and CEUS features ranged from 0.61 to 0.89. On conventional US and CEUS imaging of Xp11.2/TFE3 RCCs, the tumours were hypoechoic (6/18, 33.3%), isoechoic (8/18, 44.4%), and hyperechoic (4/18, 22.2%). The cystic component was present in 5 cases (27.8%), calcification was present in 9 cases (50.0%), and colour flow signal was present in 7 cases (38.9%). Most cases showed simultaneous wash-in (11/18, 61.1%); the peak enhancement showed hypoenhancement (6/18, 33.3%), isoenhancement (10/18, 55.6%), and hyperenhancement (2/18, 11.1%); most cases exhibited heterogeneous enhancement (12/18, 66.7%) and fast- or simultaneous-out (16/18, 88.9%); and a pseudocapsule was present in 6 cases (33.3%). In the multivariate logistic regression analysis, calcification and lower peak enhancement were more likely to be present in Xp11.2/TFE3 RCC than in ccRCC (P < 0.05), and younger age and relatively high peak enhancement were more likely to be present in Xp11.2/TFE3 RCC than in pRCC (P < 0.05). The calcification combined peak enhancement model differentiated Xp11.2/TFE3 RCC from ccRCC, and the age combined peak enhancement model differentiated Xp11.2/TFE3 RCC from pRCC with an AUC, a sensitivity and a specificity of 0.896, 94.4% and 73.3% and 0.786, 50.0% and 100.0%, respectively.ConclusionsThe specific CEUS features combined with demographic information and clinical symptoms may be helpful for differentiating Xp11.2/TFE3 RCC from ccRCC and pRCC.

Difference-Frequency Ultrasound Imaging With Non-Linear Contrast.

Conventional ultrasound imaging is based on the scattering of sound from inhomogeneities in the density and the speed of sound and is often used in medicine to resolve pathologic compared to normal tissue. Here we demonstrate a difference-frequency ultrasound (dfUS) imaging method that is based on the interaction of two sound pulses that propagate non-collinearly and intersect in space and time. The dfUS signal arises primarily from the second-order non-linear coefficient, a contrast mechanism that differs from linear and harmonic US imaging. The distinct contrast mechanism allows dfUS to image anatomic features that are not identifiable in conventional US images of salmon and pig kidney tissue. Further, dfUS produces enhanced contrast of glioblastoma tumor implanted in the mouse brain, revealing its potential for improving medical diagnosis. Progress towards a real-time system is discussed.

Tumour targeted contrast enhanced ultrasound imaging dual-modal microbubbles for diagnosis and treatment of triple negative breast cancer.

At present, the treatment of triple negative breast cancer (TNBC) is a worldwide problem, urgently requiring early precise diagnosis and effective treatment methods. In our study, we designed a type of tumour targeted dual-modal microbubbles, paclitaxel (PTX)-loaded RGD-lipid microbubbles (PTX@RGD-MBs), combined with ultrasonic targeted microbubble destruction (UTMD) to precisely diagnose TNBC and to improve the curative effect. As the first-line drug, PTX, lacking specific tumour targeting and the ability to be effectively internalized by TNBC cells, is still not effective in killing TNBC cells. For this reason, we used the tumour active targeting peptide RGD to precisely guide MBs around TNBC cells through the high affinity to the integrin αvβ3 receptor, and use UTMD to generate shear stress on cells to open transient pores in the cellular membrane, so as to improve MB penetration into the cellular membrane. Sulfur hexafluoride (SF6) as the internal gas of MBs can greatly improve the resolution and sensitivity of conventional US images through nonlinear harmonics to enhance the comparison between lesions and surrounding normal tissues. The results in our study demonstrated that RGD-MBs with UTMD were internalized by TNBC cells more effectively, leading to significant increase in intercellular drug concentrations of TNBC cells, thus achieving the best inhibitory effect on TNBC cells in vitro. Ultrasonic experiment showed that PTX@RGD-MBs produced high quality contrast enhanced ultrasound (CEUS) images in vitro and in vivo, providing a better method for diagnosis and evaluation of the TNBC. Therefore, we conclude the advantages of excellent anti-tumour effect and CEUS imaging of PTX@RGD-MBs provided a better application for diagnosis and treatment of TNBC.

Diagnostic Performance and Confidence of Contrast-Enhanced Ultrasound in the Differential Diagnosis of Cystic and Cysticlike Liver Lesions.

The aims of this study were to assess the diagnostic performance of contrast-enhanced ultrasound (CEUS) in the characterization of atypical cystic and cysticlike focal liver lesions in comparison with conventional US and to determine whether the use of CEUS can reduce the need for further diagnostic workup. In a 3-year period 48 patients with 50 atypical cystic and cysticlike lesions found at conventional US underwent CEUS. Diagnostic confirmation was obtained in cytohistopathologic examinations, with other imaging modalities, and in follow-up. Overall, there were 24 cystic lesions and 26 cysticlike solid lesions, specifically 32 benign and 18 malignant lesions. The conventional US and CEUS images and cine loops were reviewed by two blinded readers independently. Sensitivity, specificity, area under the ROC curve (Az), and interobserver agreement were calculated. Diagnostic performance improved after review of CEUS examinations by both readers (conventional US Az = 0.781 vs 0.972; CEUS Az = 0.734 vs 0.957). Interreader agreement increased, although slightly (conventional US weighted κ = 0.894; CEUS weighted κ = 0.953). In terms of differential diagnosis, the occurrence of correctly characterized lesions increased after CEUS for both readers (reader 1, 62% to 98%; reader 2, 56% to 96%). The development of low-acoustic-power CEUS has made it possible to identify several imaging features of cystic and cysticlike focal liver lesions that, in association with history and clinical findings, may help to correctly characterize them. Our data indicate the usefulness of CEUS in the evaluation of patients with these lesions.

Application of contrast-enhanced ultrasound in differential diagnosis of pleomorphic adenoma and carcinoma ex pleomorphic adenoma

Objective To assess the contrast-enhanced ultrasound (CEUS) characteristics of pleomorphic adenoma (PA) and carcinoma ex pleomorphic adenoma (CXPA). Methods A retrospective analyse was made from the contrast-enhanced ultrasonic features of 42 PA and 8 CXPA. The features included tumor size, echotexture, boundary, shape and blood flow richness on conventional US imaging and rise time (RT), time to peak (TP), peak intensity(PI), time from peak to one half(HT), mean transit time (MTT), and area under the curve(AUC) on contrast-enhanced ultrasound. Results All of PA and CXPA were hypoechoic, but there was no difference between them in shape and blood flow richness (P>0.05). 37.5% CXPA has hetergeneous echotexture with the presence of anechoic area, but it appeared in only 4.8% PA(P 0.05). Conclusions Conventional US and CEUS perfusion patten provide limited diagnostic information for distinguishing PA from CXPA. CXPA could be diagnosed by ill-defined margins, more internal anechoic area and poorly defined margins. But CEUS quantitative analysis can significantly promote the differentiation. Key words: Contrast-enhanced ultrasound; Salivary gland neoplasms; Pleomorphic adenoma

Contrast enhanced ultrasound for the evaluation of blunt pediatric abdominal trauma

IntroductionBlunt abdominal trauma is a common problem in children. Computed tomography (CT) is the gold standard for imaging in pediatric blunt abdominal trauma, however up to 50% of CTs are normal and CT carries a risk of radiation-induced cancer. Contrast enhanced ultrasound (CEUS) may allow accurate detection of abdominal organ injuries while eliminating exposure to ionizing radiation. MethodsChildren aged 7–18years with a CT-diagnosed abdominal solid organ injury underwent grayscale/power Doppler ultrasound (conventional US) and CEUS within 48h of injury. Two blinded radiologists underwent a brief training in CEUS and then interpreted the CEUS images without patient interaction. Conventional US and CEUS images were compared to CT for the presence of injury and, if present, the injury grade. Patients were monitored for contrast-related adverse reactions. ResultsTwenty one injured organs were identified by CT in eighteen children. Conventional US identified the injuries with a sensitivity of 45.2%, which increased to 85.7% using CEUS. The specificity of conventional US was 96.4% and increased to 98.6% using CEUS. The positive predictive value increased from 79.2% to 94.7% and the negative predictive value from 85.3% to 95.8%.Two patients had injuries that were missed by both radiologists on CEUS. In a 100kg, 17year old female, a grade III liver injury was not seen by either radiologist on CEUS. Her accompanying grade I kidney injury was not seen by one of the radiologist on CEUS. The second patient, a 16year old female, had a grade III splenic injury that was missed by both radiologists on CEUS. She also had an adjacent grade II kidney injury that was seen by both.Injuries, when noted, were graded within 1 grade of CT 33/35 times with CEUS.There were no adverse reactions to the contrast. ConclusionCEUS is a promising imaging modality that can detect most abdominal solid organ injuries in children while eliminating exposure to ionizing radiation. A multicenter trial is warranted before widespread use can be recommended. Level of evidenceLevel II; Diagnostic Prospective Study.

Current Status and Prospectives of CEUS in Taiwan

The clinical experiences of Levovist (Schering AG, Germany) in Taiwan (1996) were promising in the characterization of focal liver tumors. Although effective in the application in various organs, Levovist has certain shortcomings, e.g., shorter longevity of the echo-enhancing effect and incapability of being satisfactorily with harmonic imaging techniques with these limitations. Levovist was withdrew from Taiwan market in 2003. Since there was a general consensus that contrast-enhanced US (CEUS) may facilitate an accurate US diagnosis and can overcome the limitation of conventional US imaging, it was believed CEUS should be introduced to Taiwan. SonoVue, Definity, and Sonazoid are three of the more successful contrast agents in the past 10-15 years. SonoVue have been widely used in Europe and parts of Asia and Sonazoid is now in the process to obtain approval to be used in Asian countries out of Japan, Korea, and Taiwan, as well as America. Definity is now in the process to get approval in Taiwan. Other echopharmaceuticals are now designed to change the attenuation or impedance of sound for enhancing the differentiation of signals of a target organ from that of the surrounding tissue. During the past 9 years, a lot of efforts have been made to introduce USCA into the Taiwan healthcare community. In order to conduct a pilot study to convince Taiwan Food and Drug Administration (TFDA) for the possible approval of USCA to be used in Taiwan, three manufacturers (SonoVue, Sonazoid, and Definity) were invited to survey the Taiwan market. Finally, GE Healthcare got the first chance to convince the subcommittee of USCA (under the umbrella of Commission of Research and Development of Medical Ultrasound, Chinese Taipei Society of Ultrasound in Medicine, CTSUM). And Sonazoid was the priority agent accepted by CTSUM. We expect with the wide applications of USCA in Taiwan, more experience can be accumulated. The subcommittee of USCA with its 40 committee members subspecialized in different fields (e.g., gastroenterology, gynecology, cardiovascular, small parts, neurology, pediatric, etc.) will conduct more studies to find out other utilities of CEUS to benefit patients.

Added value of point shear-wave elastography in the diagnosis of acute cholecystitis.

To evaluate the added value of point shear-wave elastography (pSWE) in the diagnostic performance of conventional US for diagnosis of acute cholecystitis. B-mode and colour Doppler US and pSWE were performed prospectively in 216 patients with clinically suspected acute cholecystitis. The morphology and mural vascularity of the gallbladder and median shear wave velocity (SWV) of the right liver were evaluated. Two observers independently reviewed conventional US images and subsequently reviewed combined conventional US and pSWE images. Mean SWVs of the acute cholecystitis group (n = 91) were significantly higher than those of the control group (n = 85) in the right liver within 2 cm lateral to the gallbladder (1.56 versus 1.03 m/s, 1.39 versus 1.04 m/s, P < 0.0001) with a cut-off value of 1.29 or 1.16 m/s. The area under the receiver operating characteristic curve of both observers in the diagnosis of acute cholecystitis improved significantly from 0.790 and 0.777 to 0.963 and 0.962, respectively, after additional review of pSWE images (P < 0.0001). Diagnostic accuracy, sensitivity, specificity, positive and negative predictive values of combined image sets were higher than those of conventional US images alone. Adding pSWE to conventional US improves the diagnosis of acute cholecystitis when compared with conventional US alone. • In acute cholecystitis, stiffness of the right liver increases adjacent to the gallbladder. • The cut-off value for diagnosing acute cholecystitis was 1.29 or 1.16 m/s. • Adding pSWE to conventional US improves the diagnosis of acute cholecystitis.

Quantitative Study of Elasticity of Rabbit VX2 Liver Tumor with Alternated Cooling and Heating Treatment based on ARFI Ultrasound Imaging Technique.

Acoustic radiation force impulse (ARFI) ultrasound imaging technique is used to quantitatively evaluate the elasticity of rabbit VX2 liver tumor with alternated cooling and heating treatment (ACHT). ACHT was performed on fifteen VX2 liver tumor models established in fifteen male New Zealand white rabbits with open tumor plant. ARFI was performed on day 0, 1, 7 and 14 after ACHT and shear wave velocity (SWV) in ARFI was recorded to evaluate the elasticity of the treated area. The SWV value of the lesion on day 0, 1, 7 and 14 was 2.33 ± 0.19 m/s, 3.09 ± 0.40 m/s, 2.64 ± 0.37 m/s and 2.26 ± 0.24 m/s, respectively, indicating the treated areas get stiffer on day 1 and then get softer gradually by day. All the difference between adjacent time points was statistically significant. The SWV value of different parts on day 7 approved that the hardness of the treated area is heterogenous: the treated area in the center >the peripheral strip-shaped area >normal liver tissues, consistent with pathological changes. Meanwhile, ARFI combined with conventional US imaging can qualitatively and quantitatively exam the healing process of rabbit VX2 liver tumor after ACHT, and corresponds well to the pathological results.

The use of contrast-enhanced ultrasound in blunt abdominal trauma: advantages and limitations

Computed tomography (CT) is the imaging method of choice in the assessment of multiple trauma patients. However, in patients who suffered from low-energy abdominal trauma, the use of CT is controversial, since the probability of injury is low and therefore most of the studies are normal. Thus, conventional US imaging has increasingly been employed as the initial imaging modality in the work-up of minor traumatic emergency condition. More recently, the introduction of a new contrast-enhanced ultrasound (CEUS) technique, using second-generation ultrasound contrast agents, has led to a notable increase in the diagnostic accuracy of US in many organs. Therefore, in trauma patients, following assessment with conventional US imaging, a CEUS exam can be performed, to provide a more reliable assessment of solid organ injuries. CEUS has the potential to detect active bleeding from a variety of traumatic origins. Similar to CT, active extravasation is considered when there is evidence of contrast agent collection with echogenicity similar to that of an adjacent vessel. On the other hand, at least some drawbacks have to be addressed, including operator competence and reduced panoramic view. Moreover, CEUS, like conventional US imaging, cannot depict some lesions, such as diaphragmatic ruptures, bowel, and mesenteric traumatic injuries. This technique represents a non-invasive and repeatable method that can be performed at patient's bedside and is therefore extremely helpful for the follow-up of solid organs traumas managed conservatively, especially in pediatric patients and women of fertile age. Moreover, it may reduce the number of CT scans and expedite patient discharge.

Ultrasound Transmission Tomography Imaging of Structure of Breast Elastography Phantom Compared to US, CT and MRI

Abstract The paper presents an analysis of the results of ultrasound transmission tomography (UTT) imaging of the internal structure of a breast elastography phantom used for biopsy training, and compares them with the results of CT, MRI and, conventional US imaging; the results of the phantom examination were the basis for the analysis of UTT method resolution. The obtained UTT, CT and MRI images of the CIRS Model 059 breast phantom structure show comparable (in the context of size and location) heterogeneities inside it. The UTT image of distribution of the ultrasound velocity clearly demonstrates continuous changes of density. The UTT image of derivative of attenuation coefficient in relation to frequency is better for visualising sharp edges, and the UTT image of the distribution of attenuation coefficient visualises continuous and stepped changes in an indirect way. The inclusions visualized by CT have sharply delineated edges but are hardly distinguishable from the phantom gel background even with increased image contrast. MRI images of the studied phantom relatively clearly show inclusions in the structure. Ultrasonography images do not show any diversification of the structure of the phantom. The obtained examination results indicate that, if the scanning process is accelerated, ultrasound transmission tomography method can be successfully used to detect and diagnose early breast malignant lesions. Ultrasonic transmission tomography imaging can be applied in medicine for diagnostic examination of women’s breasts and similarly for X-ray computed tomography, while eliminating the need to expose patients to the harmful ionising radiation.

Contrast-enhanced ultrasonography to diagnose gallbladder perforation

AimThe purpose of this study was to evaluate contrast-enhanced ultrasonography (CEUS) as a modality for diagnosing perforation of the gallbladder (GB) and pericholecystic hepatic abscess. MethodsThis retrospective study comprised 6 patients with acute cholecystitis and GB perforation plus pericholecystic hepatic abscess who underwent conventional US and CEUS imaging. The following sonographic features were examined: GB contour, defect in the GB wall, and pericholecystic hepatic mass. The findings of conventional US and CEUS were compared. ResultsConventional US revealed a defect in the GB wall in 2 patients and partially obscured GB wall in 4 patients. Pericholecystic masses were visualized as isohypoechoic masses in 3 and mixed cystic-solid masses in 3 patients. Contrast-enhanced US revealed hyperenhancement of the GB wall during the early arterial phase, and a defect was seen in every patient. The pericholecystic masses showed heterogeneous enhancement with a honeycomb-like appearance during the arterial phase–interpreted abscesses. ConclusionContrast-enhanced US clearly visualized defects in the GB wall and pericholecystic abscesses in patients with GB perforation. The results indicate that CEUS is a useful modality for the diagnosis of GB perforation.