Point shear wave elastography application in assessment pancreas tissue stiffness: A pilot study.

The local shear wave speed (in meters per second) and Young modulus (in kilopascals) of normal thyroid glands were defined in healthy children to determine reference values.This prospective study assessed 107 pediatric cases (age interval, 3-17 years; mean, 9.37 ± 3.68 years), including 52 boys and 55 girls. The study group included children without thyroid gland disease (autoimmune, infectious, or neoplastic). Data about the sex, age, weight, height, and body mass index (BMI) of the subjects were recorded for all subjects. Elasticity values were measured from 3 different sites in both thyroid lobes and averaged.Median values for elasticity and shear wave velocity measured in bilateral thyroid lobes were 6.38 ± 1.97 kPa (range, 3.00-12.5 kPa) and 1.45 ± 0.21 m/s (range, 1.03-2.04 m/s) on the right and 8.81 ± 3.00 kPa (range, 3.80-22.6 kPa) and 1.69 ± 0.26 m/s (range, 1.13-2.68 m/s) on the left. There was no significant difference between the elasticity values for the right and left thyroid lobes between boys and girls. There was a positive correlation between right thyroid lobe mean elasticity (in kilopascals) and shear wave velocity (in meters per second) values with age, BMI, and right thyroid lobe volume in the whole group. No significant correlation was found between left thyroid lobe mean elasticity (in kilopascals) and shear wave velocity (in meters per second) values with age, BMI, and left thyroid lobe volume in the study population.This study determined mean elasticity and shear wave velocity values for thyroid gland in healthy children. This information can be used as a baseline for the investigation of thyroid diseases.

Acoustic Radiation Force Impulse (ARFI) shear wave imaging is a noninvasive method of assessment of the liver to detect fibrosis in patients with chronic hepatitis and nonalcoholic fatty liver disease (NAFLD). The aim of this retrospective study was to investigate whether noninvasive measurement of shear wave velocity (SWV) by ARFI shear wave imaging has a potential usefulness for detection of fibrosis secondary to NAFLD in patients with morbid obesity. Twenty-eight morbidly obese patients were included in this study. NAFLD and fibrosis were classified according to the nonalcoholic steatohepatitis (NASH) Clinical Research Network NAFLD activity score. SWV was quantified by ARFI imaging. Component steatosis, inflammation and ballooning scores, and fibrosis staging were correlated with SWV, and diagnostic accuracy of ARFI for fibrosis was assessed. There was a decrease in mean SWV with increasing hepatic steatosis (P = .057). The SWV showed a significant negative correlation (r = -0.417, P = .011) with steatosis grade. The mean SWV was neither significantly different nor correlating with the obesity classes based on body mass index (BMI), steatosis grades, inflammation grades, ballooning grades, and fibrosis stages of NAFLD. Receiver operating characteristic analysis showed no significant area under curve for diagnosis of fibrosis using SWV. Valid SWV could be acquired in all subjects; however, only 21.42% fulfilled the interquartile range criterion. ARFI SWV values do not correlate with fibrosis on liver biopsy in morbidly obese patients and lack accuracy for diagnosis. Discordant values may be related to higher BMI and increasing hepatic steatosis.

The purpose of this study is to evaluate pancreatic stiffness by ARFI abdominal elastography. In the current literature, there are relatively few studies that have assessed the clinical utility of this technique. A number of 37 healthy subjects were included. The data were collected in a prospective manner and afterwards included in an observational, analytical and longitudinal study. Subsequently viewing the pancreatic parenchyma in bidimensional mode (2D-US) mode, 10 shear wave velocity (SWV) measurements for each segment: head, body and tail were performed. Statistical analysis by regression models targeted also the possible influence of other factors in assessing SWV. A comparative analysis was performed regarding the statistical significance of 5 versus 10 SWV measurements for each segment. The pancreas was entirely evaluated in all subjects. The mean SWV from the entire parenchyma was 1.216 m/s±0.36 and between the three segments SWV were similar (head: 1.224 m/s, body: 1.227 m/s and tail: 1.191 m/s). A ratio of the IQR/Median >0.4 was interpreted as statistically invalid, relevant data being highlighted in the percentage of 83.78% for the head of the pancreas, 78.37% for the body, and 67.56% at the caudal level. Significant correlations were observed between the data (mean and median SWV) provided by the group with 5 measurements of the SWV versus the standard group: 93.9% for the head, 96.6% for the body, and 98.7% accordingly to the tail. SWV determination by percutaneous approach represents a useful imaging method for evaluating pancreatic stiffness, of course within these limitations. Because we did not observe statistically significant differences between the results obtained by 5 or 10 measurements, we suggest that it would be sufficient to perform only five measurements of the SWV per pancreatic segment. The data obtained in the normal pancreas could be used in future comparative assessments regarding the inflammatory or tumoral pathology of the pancreas.

Section 1 Physical properties and laboratory measurements.- Shear waves in marine sediments-bridging the gap from theory to field applications (Opening paper).- Surface waves in poro-viscoelastic marine sediments.- An investigation of causality for Biot models by using Kramers-Kronig relations.- Soil properties for shear wave propagation (Invited).- The relevance of shear waves for structural subsurface investigations.- Experimental investigation of seismic surface waves in the seafloor.- Laboratory studies on pulsed leaky Rayleigh wave components in a water layer over a solid bottom.- Assessment of shear strength of the sea bottom from shear wave velocity measurements on box cores and in-situ.- Numerical modelling and laboratory experiments on underwater sound propagation over a shear supporting bottom.- A review of laboratory shear wave techniques and attenuation measurements with particular reference to the resonant column (Invited).- Relationship between acoustic and mechanical properties of two marine clays.- A laboratory method to investigate shear waves in a soft soil consolidating under self weight.- Laboratory measurements of acoustic properties of periplatform carbonate sediments.- Comparison of measured compressional and shear wave velocity values with predictions from Biot theory.- Wave velocities in sediments.- Shear wave attenuation in unconsolidated laboratory sediments.- Shear wave velocities of glacio-marine sediments: Barents Sea.- Rock acoustics: relevance of the porous viscoelastic model.- Influence of stress state and stress history on acoustic wave propagation in sedimentary rocks.- Section 2 Field experiments and interpretation.- A summary of DREA observations of interface waves at the seabed.- Observations of the relative contributions of waterborne and sediment paths to the received acoustic signal.- Shear-wave anisotropy in marine sediments around Britain from surface sources.- Refraction measurement of shear wave anisotropy in shallow marine sediments and implications for reflection processing.- Spatial variability in ground motion: effects of material heterogeneity in seafloor sediments.- Implications of deep-water seismometer array measurements for Scholte wave propagation.- Shear wave velocity structure from interface waves at two deep water sites in the Pacific ocean.- The effects of shear velocity structure on seafloor noise.- Concurrent observations of directional spectra of ocean surface waves and microseisms from an ocean subbottom seismometer (OSS) array.- Wave propagation in a borehole (Invited).- Application of shear wave measurements in boreholes.- Experience with the seismic cone penetrometer in offshore site Investigations.- Comparison of techniques for shear wave velocity and attenuation measurements.- Shear wave velocity gradients in near-surface marine sediment.- ISSAMS: an in situ sediment acoustic measurement system.- Small-scale in situ measurements of S-H velocity in surficial sedimentary deposits: localised textural and biological controls.- In situ measurements of shear-wave velocity in ocean sediments.- Seafloor shear wave velocity data acquisition: procedures and pitfalls.- Mapping of the sea bed via in situ shear wave (SH) velocities.- Observations of split shear-waves from young ocean crust.- Estimation of shear-wave speed in ocean-bottom sediments by comparing oblique-angle reflectivity measurements with normal incidence data.- SedimentQpfrom spectral ratios of converted shear reflections.- Constraints on shear velocities in deep-ocean sediments as determined from deep-tow multichannel seismic data.- Changes inPandSvelocities caused by subduction related sediment accretion off Washington/Oregon.- Compressional and shear wave velocities in the upper crust.- Sedimentary shear modulus and shear speed profiles from a gravity wave inversion.- Measurements of compressional wave and shear wave speeds, attenuation, permeability, and porosity in marine sediments.- Sea-bed shear moduli from measurements of tidally induced pore pressures.- Section 3 Modelling and inversion techniques.- Excess attenuation in low-frequency shallow-water acoustics: a shear wave effect? (Invited).- Sensitivity of bottom loss to attenuation and shear conversion.- The effect of shear wave attenuation on acoustic bottom loss resonance in marine sediments.- The influence of sediment rigidity on the plane-wave reflection coefficient.- Shear wave conversion due to subbottom facets.- A seismo-acoustic finite element model for underwater acoustic propagation.- Finite difference modelling of shear waves.- A stable higher-order elastic parabolic equation with application to Scholte wave propagation.- ELASTIC PE: a parabolic approximation for propagation modelling of shear wave effects in sediment layers.- Computation of shear waves by integral equations methods in stratified media.- Normal modes identification in shallow water using spectral analysis: theory and experiments.- Estimation of geoacoustic properties by inversion of acoustic field data (Invited).- A fast simulated annealing algorithm for the inversion of marine sediment seismo-acoustic parameters.- Determination of the sediment shear speed profiles from phase and group velocity dispersion data of SH wave.- Measurement of the elastic properties of the ocean bottom by inversion of reflection amplitude data.- Surface wave inversion for shear wave velocity (Invited).- Determination of shear velocity profiles by inversion of interface wave data.- Using synthetic seismograms to determine shear wave velocities in sediments from ocean bottom seismometer refraction observations.- Analytical investigation of seismic surface waves in the seafloor.- List of Participants.- Author Index.

Elastography has not been widely applied to the gastrointestinal tract. The bowel wall's normal elasticity values are still unknown and are necessary for studies of gastrointestinal diseases. This study explores the feasibility of using shear wave elastography (SWE) to measure the terminal ileum wall stiffness in healthy subjects and establish the corresponding normal ranges of elasticity values. This observational study recruited 139 healthy adult volunteers from April to July 2020. All examinations were performed in the anterior terminal ileum wall. Shear wave velocity (SWV) and Young's modulus (E) values were measured in the midline on longitudinal sections and replicated different operators' obtained data. Also, bowel wall thickness (BWT) and depth were recorded. Subgroups were classified according to the volunteers' gender, age, body mass index (BMI), BWT, and depth. The intra-class correlation coefficient was calculated to analyze inter- and intra-operator consistency, and independent t-tests and one-way analysis of variance were used to explore the differences in variables. The inter- and intra-operator agreements were good to excellent by different operators and in the replicated measurements (intra-operator consistency: 0.963; inter-operator consistency: 0.842). In all volunteers, the mean SWV was 1.08±0.25 m/s, the mean E value was 3.84±1.84 kPa, and the median BWT was 2 mm. SWV and E did not show significant differences according to gender (P=0.589), age (P=0.738), BMI (P=0.678), depth (P=0.375), or BWT (P=0.410). BWT did not show significant differences according to age (P=0.142), BMI (P=0.863), or depth (P=0.368). SWE can be used in terminal ileum wall stiffness measurements with good reliability, and the SWE values do not appear to vary significantly according to different physiological factors. The corresponding elasticity ranges of the terminal ileum in normal adults were acquired.

Aim of the study was to examine the associations between abductor pollicis brevis (APB) muscle stiffness evaluated by shear wave elastography and electrodiagnostic study findings in patients with carpal tunnel syndrome. The association between shear wave elastography and APB muscle echogenicity was also examined. This prospective study included patients who were referred to electrodiagnostic studies because of upper limb symptoms. The electrodiagnostic studies consisted of nerve conduction studies and needle-electromyography. Abductor pollicis brevis muscle shear wave velocity was measured, and muscle echogenicity assessed using the Heckmatt grading scale. In total, 97 hands were included in the nerve conduction studies. Of these, 53 APB muscles were further examined with needle-electromyography. Shear wave velocity correlated positively with the neurophysiologic severity of carpal tunnel syndrome ( r = 0.449, P = 0.028, N = 26). Mean shear wave velocity was faster in the APB muscles with neurogenic findings (mean 2.72 m/second, ±SD 0.36) than muscles with normal findings (2.48 m/second, ±SD 0.34, P = 0.036). In receiver operating characteristic analysis, the best shear wave velocity cutoff value was 2.66 m/second. With this cutoff value, the sensitivity was 0.692, while the 1-specificity was 0.233. Only seven APB muscles showed increased echogenicity. Shear wave velocity of APB muscle is positively associated with the neurophysiologic severity of carpal tunnel syndrome. Carpal tunnel syndrome-related axonal damage also seems to increase shear wave velocity in APB muscle; however, according to the receiver operating characteristic analysis, the method is not yet suitable for clinical use to define muscle denervation. The findings of this study show that shear wave elastography has potential as an additional clinical tool in the diagnostics of carpal tunnel syndrome.

Elastosonography is a non-invasive diagnostic method to evaluate tissue stiffness. The aim of our study was to demonstrate the applicability and efficacy of elastosonography to differentiate benign vs malignant subpleural lung lesions compared to clinical, radiological and histological findings.We performed both strain and shear wave velocity (SWV) elastosonography on subpleural lung lesions. Moreover, we elaborated a composite score called ”elasto index”.Fourteen patients, 10 males and 4 females were recruited. On strain elastography, 9 lesions showed a hard pattern (type 3), 3 lesions showed an intermediate pattern (type 2), and 2 lesions a soft pattern (type 1). All lesions showed a mean SWV value of 4.46 ± 2.37 m/second. The mean SWV for malignant lesions (n = 6) was 5.92 ± 2.8 m/second. The mean SWV for benign lesions (n = 8) was 3.36 ± 1.20 m/second. SWV shows an area under the curve (AUC) of 0.792, and the Youden index shows a value of 3.6 m/second. The ROC curve elaborated for the diagnosis of malignancy by strain elastography showed an AUC of 0.688. ROC curve for the diagnosis of malignancy by elasto index demonstrated an AUC of 0.802.SWV values obtained by ARFI elastosonographic method are higher in malignant lung lesions (mean SWV: 5.92 m/second) than in benign ones (mean SWV: 3.36); a composite score (elasto index) is characterized by better statistical significance for the differentiation of the lesions.

This study aims to search the association of obesity, metabolic parameters, and abdominal subcutaneous white adipose tissue (scWAT) stiffness in children and adolescents using ultrasound point shear wave elastography (p-SWE). One hundred and forty overweight or obese children referred to as overweight were included in the study group. Thirty-two lean children, referred to as leans, were included in the control group. In all individuals, scWAT shear wave speed (SWS) was measured with p-SWE. ScWAT stiffness was compared between the two groups. The association of anthropometric, metabolic factors and scWAT stiffness is determined. Weight, body mass index, body mass index-standard deviation score, systolic blood pressure, diastolic blood pressure, alanine aminotransferase, fasting insulin were significantly higher in the overweight group (p<0,05). ScWAT SWS was significantly different between the groups (p=0.006) The median value of scWAT SWS was 1,5 m/s (range; 0.9-3.8), 1.23 m/s (range; 0.7-3.1) for leans and overweight, respectively. In leans, no significant difference was found between boys and girls for scWAT SWS (p=0.094). In overweight, a significant difference was found for scWAT SWS between boys and girls (p=0.022). The scWAT stiffness is lower in overweight than leans. Gender has a pivotal role in scWAT stiffness. If supported with future long-time follow-up studies, p-SWE may be compatible with assessing subcutaneous adipose tissue changes related to obesity and metabolic complications in childhood and adolescence.

ObjectiveParathyroid carcinoma (PC) and atypical parathyroid tumor (APT) are rare parathyroid disorders carrying the risk of recurrence of varying degrees. This study aims to explore the value of 2D-shear wave elastography (SWE) in the discrimination of PC/APT among suspicious parathyroid lesions.Methods and materialsIn this prospective study, patients with primary hyperparathyroidism and suspicious parathyroid lesions on ultrasonography (US) were recruited. All the lesions were assessed by SWE before surgery. The velocity (m/s), Young’s modulus (Kpa), and elastogram of SWE were compared between pathologically proven parathyroid carcinoma or atypical parathyroid tumor (Group1) and parathyroid adenoma (Group2). All the SWE parameters were displayed at the setting of 50 or 70 kPa. Correlations between SWE and the lesion size as well as biochemical parameters were analyzed.Results36 target lesions were enrolled for analysis. The mean shear wave velocity (SWV) between the two groups was 2.4 m/s vs 1.9 m/s, respectively, while the mean Young’s modulus was 11.1 kPa vs 18.2 kPa, respectively. The cut-off values are 2.35 m/s and 17.05 kPa correspondingly. The sensitivity and specificity of the selecting cut-off values were 0.56 vs 0.63 and 0.95 vs 1.0 (area under the curve [AUC]: 0.813 vs 0.852 [95% confidence interval (CI): 0.669–0.956 vs 0.720–0.983]; p < 0.001, p < 0.001; respectively). In contrast, the max SWV and Young’s modulus showed a better sensitivity of 0.75 and 0.81, respectively. The “colored lesion” and “stiff rim” patterns on the elastogram are more indicated in parathyroid carcinoma and atypical parathyroid tumor, whereas the negative elastogram prevails in parathyroid adenoma. The SWV and Young’s modulus of the parathyroid lesions were independent of the tumor size, but the max SWV and Young’s modulus slightly correlated with serum parathyroid hormone concentration (PTH) (r = 0.398, p = 0.016; r = 0.396, p = 0.017).Conclusions2D-shear wave elastography plays a useful role in the preoperative assessment of parathyroid lesions with suspicious malignancy. The mean SWV and Young’s modulus are advised as the favored diagnostic parameter with the best AUC and excellent specificities, while the max SWV and Young’s modulus are more sensitive to distinguish the PC and APT compared with other parameters.

PurposeAsymptomatic primary hyperparathyroidism (aPHPT) has been recognized as a condition that can lead to renal complications. Timely identification of prognostic indicators for renal impairment holds the potential to facilitate proactive monitoring and treatment strategies in these patients. This study aims to investigate the utility of acoustic radiation force impulse (ARFI) imaging and renal resistive index (RRI), in identifying renal parenchymal and vascular changes in patients with aPHPT.MethodsForty-two patients with aPHPT and 42 controls matched for age, sex, and body mass index were included in the study. The presence of renovascular changes was evaluated by RRI measurement with Doppler ultrasonography, and the presence of renal parenchymal involvement was evaluated by ARFI quantification, given as shear wave velocity (SWV).ResultsIn aPHPT patients, both the mean RRI and mean SWV values exhibited substantial elevation compared to the control group (P < 0.001 for both). Significant associations were observed between SWV values and serum calcium, parathyroid hormone (PTH), and adenoma size within the patient group (P < 0.001, P < 0.001, P = 0.016, respectively). Similarly, the mean RRI demonstrated positive correlations with serum calcium and PTH levels in the patient group (P< 0.001, P = 0.011, respectively). Multivariate linear regression analysis underscored the connection between mean RRI and mean SWV values with serum calcium levels within the patient group. In addition, serum PTH levels affected mean SWV positively and significantly.ConclusionThe use of ARFI imaging and RRI measurements appears to hold potential in identifying renal involvement in patients with aPHPT.

Purpose To evaluate the correlation between ultrasonographic (US) point shear-wave elastography (SWE) and magnetic resonance (MR) elastography liver shear-wave speed (SWS) measurements in a pediatric population and to determine if US data dispersion affects this relationship. Materials and Methods Institutional review board approval was obtained for this HIPAA-compliant investigation; informed consent and patient assent (as indicated) were obtained. Patients (age range, 0-21 years) undergoing clinical liver MR elastography between July 2014 and November 2015 were prospectively enrolled. Patients underwent two-dimensional gradient-recalled-echo 1.5-T MR elastography with point SWE performed immediately before or immediately after MR elastography. Spearman rank correlation coefficients were calculated to assess the relationship and agreement between point SWE and MR elastography SWS measurements. Uni- and multivariate logistic regression were performed to identify predictors of US data dispersion, with the best multivariate model selected based on Akaike information criterion. Results A total of 55 patients (24 female) were enrolled (mean age, 14.0 years ± 3.9 (standard deviation) (range, 3.5-21.4 years). There was fair correlation between point SWE and MR elastography SWS values for all patients (ρ = 0.33, P = .016). Correlation was substantial, however, when including only patients with minimal US data dispersion (n = 26, ρ = 0.61, P = .001). Mean body mass index (BMI) was significantly lower in patients with minimal US data dispersion than in those with substantial US data dispersion (25.4 kg/m2 ± 7.8 vs 32.3 kg/m2 ± 8.3, P = .003). At univariate analysis, BMI (odds ratio, 1.12; 95% confidence interval [CI]: 1.03, 1.21; P = .006) and abdominal wall thickness (odds ratio, 2.50; 95% CI: 1.32, 4.74; P = .005) were significant predictors of US data dispersion. In the best multivariate model, BMI was the only significant predictor (odds ratio, 1.11; 95% CI: 1.03, 1.20; P = .009). Conclusion Point SWE and MR elastography liver SWS measurements correlate well in patients with a BMI of less than 30 kg/m2 and minimal US data dispersion; increasing US data dispersion is directly related to a higher BMI. © RSNA, 2016.

A measurement method of shear wave (SW) velocity for elastography by using a conventional B-mode scan with a focused ultrasound system is demonstrated in this paper. In the B-mode scan, there is a scanning time delay among the sequential A-mode measurements. This scanning time delay causes an artificial spatial frequency difference between the induced SW and undesired SWs reflected at tissue boundaries. Therefore, the reflected SW can be removed from the measured SWs using a spatial frequency filter. In our previous study, the SW propagating in the same direction as the B-mode scanning direction was used to measure the SW velocity. In such configuration, a prior knowledge was required whether the values of the SW velocity of a specimen are greater or smaller than the B-mode scanning speed, which may not be known for an arbitrary specimen. In order to address such shortcoming, the measurement configuration was modified in this paper so that such prior knowledge is no longer required. The method was verified by using a soft tissue mimicking phantom with a relatively stiffer cylindrical inclusion. Image contrast between the two different materials was successfully observed in the SW velocity map obtained.

: In general population, chronic liver disease is a great public health problem. Liver fibrosis, a common pattern in the usual causes of chronic liver disease, involves the gathering of collagen and other macromolecules inside the extracellular matrix. Fibrosis tends to proceed, leading to liver dysfunction, portal hypertension, and eventually cirrhosis. Liver biopsy is the gold standard for the diagnosing of liver fibrosis, and unfortunately it is invasive, expensive, with sampling variability and probable complications (mortality rate is procedure-related: one in 10,00012,000). For patients with chronic liver disease, it is important to delineate the degree and grading of fibrosis progression. Ultrasonography (US) provides ideal noninvasive assessment for diffuse liver disease because of its low cost and wide availability. Conventional B-mode US is good for the diagnosis of advanced cirrhosis, but is insensitive for fibrosis. Elastography may be employed as a substitute diagnostic technique for fibrosis. The METAVIR scoring system assigns fibrosis to five stages of F0: no fibrosis, F1: portal and periportal fibrosis with no septum, F2: portal and periportal fibrosis with rare septa, F3: portal and periportal fibrosis with many septa, F4: cirrhosis). In elastography, a mechanical force (compression or vibration) is applied to the soft tissues, and a conventional imaging technique such as US or MR imaging is used to create a map of soft-tissue deformation. There are two types of elastography: static and dynamic elastography. Static elastography is now a more common type of elastographic imaging. In this method, a single and very small compressive force is used by pressing with the ultrasound probe, typically and then the displacement of tissue is calculated. Static elastography has been widely used with superficial organs. It is more difficult to apply in deeper organs, and also the qualitative figures have not been displayed to have value for detection of liver fibrosis by using a vibratory stimulus to produce shear waves (which slowly pass through tissues) to be tracked by ultrasound. The spreading rate of shear waves depends upon the shear modulus of tissues, which is usually proportional to the Youngs modulus directly. Hence, quantifying tissue stiffness is possible by using this method. The first ultrasound system to apply this method is the Fibroscan (by Echosens) which can evaluate liver fibrosis. Shear waves are sent into the liver by a piston at the center of the probe, and the shear waves velocity is used to assess the shear modulus. This tool has proved feasible for the noninvasive diagnosis of moderate and severe fibrosis, but mild changes are not detected. Development of other systems to apply acoustic radiation force imaging (ARFI) (such as the Siemens S2000) by pushing on organs with a high-powered ultrasound pulse is under way. Currently, there are three main techniques to evaluate liver stiffness: transient elastography (FibroScan by Echosens), acoustic radiation force impulse (ARFI) imaging, and shear-wave (SW) elastography . Among these methods, transient elastography offers the capacity to estimate mean tissue stiffness noninvasively. Several recent studies have proved that the measurements of liver stiffness with transient elastography are well correlated with the METAVIR stages of fibrosis. In addition, transient elastography is helpful as it can be performed repeatedly. However, it is not a real-time technique because the sonographic images are not visible during the measurement. In patients with hepatosteatosis and increased body mass index (BMI), the reproducibility of transient elastography is substantially reduced as the modality of ultrasonography itself has restrictions for visualizing the liver clearly in these patients. Real-time sonoelastography is another method for the evaluation of tissue elasticity. It uses a B-mode ultrasound, combining with elastography with the conventional US scanner. This device estimates the relative hardness of the organs and displays this data as real-time color images. It can show tissue elasticity images and conventional B-mode images at the same time. There are many reports and approaches to evaluate liver stiffness without liver biopsy. Among them, the FibroScan appears useful.

Crohn’s disease (CD) is a chronic inflammatory disease necessitating surgical bowel resection in 60% of patients due to stricturing. CD stricturing is the result of bowel wall thickening composed of a mixture of inflammatory and fibrotic intestinal wall changes. Over time, cycles of inflammation and healing shift the stricture pathology from largely inflammatory to primarily fibrotic. Predominantly fibrotic strictures are unresponsive to anti-inflammatory therapies and require endoscopic dilation or surgery. Decisions between medical and surgical therapy are plagued by the difficulty of determining whether bowel wall thickening is the result of inflammation or fibrosis. The current practice of empirically using anti-inflammatory therapy in most patients with CD-related bowel wall thickening and obstructive symptoms in the hope of success leads to many unnecessary side effects, infections, worse surgical outcomes, and long delays of appropriate surgical intervention when significant fibrostenotic disease is already present. Ultrasound stiffness imaging, using acoustic radiation force impulse imaging (ARFI), provides real-time non-invasive bedside elastography of bowel wall reported as shear wave velocity (SWV). We hypothesize that AFRI SWV of luminal stricturing disease will stratify medically responsive (inflammatory) from non-responsive (predominantly fibrotic) ileal Crohn’s disease; we present the interim analysis. Subjects with established ileal Crohn’s disease hospitalized for small bowel obstruction (defined as CT evidence of small bowel dilation >3.5cm) and scheduled to receive methylprednisone were enrolled. Within 48 hours of admission subjects underwent bedside ultrasound using Acuson S3000 with ARFI Virtual-Touch software package (Siemens, USA). SWV of the lateral, anterior, and medial portions of diseased ileum at 0% and 10% strain were collected in triplicate at baseline and Day 3. Subject demographic data, medical history, laboratory values and Harvey Bradshaw Index (HBI) were assessed at both time points. Ultrasound SWV values were compared to a primary outcome of surgical bowel resection for obstructive disease within 90 days. In 10 subjects with complete follow up to date, 4/10 have undergone surgical bowel resection within 90 days. Patient demographics, BMI, anti-TNF and immunomodulator use, and prednisone use prior to hospitalization did not significantly differ between surgical and non-surgical groups. Mean SWV at 0% strain (no freehand force) did not discriminate those requiring surgery within 90 days (1.42 [1.28–1.53] versus 1.56 [1.44–1.73] m/s, P = 0.154). When applying 10% freehand strain to the affected segment, baseline SWV yielded improved discrimination between those requiring surgery within 90 days (2.20 [1.74–2.39] m/s) versus subjects avoiding surgery (1.81 [1.54–2.09] m/s), although statistical significance was not reached at this interim point of the study, P = 0.066. No significant difference in SWV change between baseline and day 3 of methylprednisone was observed between the surgical and non-surgical cohorts. Ultrasound stiffness imaging by ARFI elastography demonstrates a trend of increasing shear wave velocities in subjects with obstructive ileal Crohn's requiring near-term surgical resection, although at this interim analysis point trends have not reached statistical significance. The data presented suggests that SWV non-invasive bowel wall stiffness measurements at higher strain values (20%-30%) may better predict the success or futility of medical therapy in subjects with obstructive Crohn's disease.

Liver stiffness measured by acoustic radiation force impulse elastography reflects the severity of liver damage and prognosis in patients with acute liver failure.