Quantitative Elastography Research Articles

Role of elastography in characterization of solid breast masses

Objectives The aim of this study was to study the diagnostic performance of elastography in characterization of solid breast masses. Background Elastography is an imaging modality that can calculate the elasticity of tissues, based on the well-established principle that benign lesions are soft and malignant lesions are hard. It is an easy procedure with high diagnostic performance, which can be easily integrated with the B-mode ultrasound examination in the same session to improve its specificity. Patients and methods A total of 30 female patients were included in this prospective study in the period from February 2016 to February 2017 with a complaint of breast mass. We examined the patients using ultrasonography and strain elastography. Then, we compared the findings of ultrasonography and elastography with pathology findings to assess their diagnostic performance. Results Among the 30 breast masses, 14 were benign and 16 were malignant. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ultrasonography were 100, 43, 67, and 100%, respectively. Qualitative elastography (Tsukuba score) had a sensitivity of 69%, specificity of 86%, PPV of 85%, and NPV of 71%. Quantitative elastography, assessed using the strain ratio, was a good discriminant for malignancy (area under the receiver operating curve = 0.94, P = 0.001). Our results revealed a cutoff point for malignancy of more than2.7; by using this threshold, the diagnostic performance of the strain ratio was 94% sensitivity, 86% specificity, 88% PPV, and 92%NPV. Conclusion Elastography has great diagnostic performance in distinguishing between benign and malignant breast masses.

Ultrasound elastography as a potential diagnostic aid in oral submucous fibrosis.

Background:Oral submucous fibrosis (OSMF) is a well-recognized “potentially malignant” disorder. It mostly affects the productive population of young adults and adolescents. The diagnosis of oral submucous fibrosis is primarily clinical and subjective. The only objective diagnostic method for OSMF is tissue biopsy. This study was conducted to find the potential use of ultrasound elastography to objectively quantify the clinical presentation in accordance with severity of the clinical condition in OSMF.Materials and Methods:The study sample consisted of 27 clinically diagnosed and staged participants with OSMF. Transcutaneous ultrasonography was done by a single operator on GE Logiq E9 machine with a 6–15 MHz linear matrix probe. Color-coded scheme was used to qualitatively grade the eight different zones of oral mucosa with the use of stress–strain elastography. The grades ranged from 0 to 5, where 0 represented artifacts and color range from red to blue corresponded to varying degree of increasing tissue stiffness. Clinical stage 1, 2, and 3 corresponded to mouth opening of >30 mm, 20–30 mm, and <20 mm, respectively. The summative elastography score range as follows: 8–10, 11–14, and ≥15 represented the respective degree of tissue stiffness from soft, mild stiff to severe stiff.Results:The results obtained by Pearson's correlation between the elastographic grading and clinical grading came out to be 0.007, and it was highly significant. The sensitivity and specificity of the diagnostic method were 90.9% and 20%, respectively.Conclusion:The advantages of ultrasound elastography as a diagnostic tool over the subjective clinical method of diagnosis and staging of OSMF looks promising. Further studies should be conducted with a suitable specific transducer probe and with quantitative diagnostic elastography method.

Quantitative elastography of Achilles tendon using Shear Wave Elastography (SWE): correlation with zonal anatomy

Quantitative elastography of Achilles tendon using Shear Wave Elastography (SWE): correlation with zonal anatomy

Characterization of Testicular Masses in Adults: Performance of Combined Quantitative Shear Wave Elastography and Conventional Ultrasound

We prospectively evaluated the performance of combined shear wave elastography (SWE) and conventional ultrasound (US) for the characterization of 89 testicular focal masses. Testes were evaluated with B-mode, color Doppler and SWE measurements, locating a region of interest on the normal and pathologic parenchyma. Thirty-seven malignant tumors (MTs), 12 burned out tumors (BOTs), 28 Leydig cell tumors (LCTs), 2 dermoid cysts and other benign lesions were included. MTs + BOTs exhibited more microliths and macrocalcifications compared with benign lesions (p < 10–4). LCTs manifested mostly a dominant peripheral vascularization pattern compared with other lesions. MTs + BOTs were stiffer compared with benign lesions (p < 2 × 10–4) but with a moderate area under the receiver operating characteristic curve (AUROC) of 80%. By focusing on LCTs versus MTs + BOTs, diagnostic performance led to an AUROC of 89% for the best stiffness parameter. For combined conventional US and SWE, the diagnostic performance to differentiate all benign lesions versus MTs + BOTs and LCTs versus MTs + BOTs increased to AUROCs of 93% and 98%, respectively.

15: Novel, sensor-based quantitative cervical elastography: objective quantification of cervical softness

Cervical ripening is a necessary physiologic phenomenon that precedes all labor, both term and preterm. Tissue elastography works by applying pressure to tissue and measuring tissue displacement. It is quantified by Young’s modulus, a ratio of pressure to displacement. The harder the tissue, the less displacement and the higher the Young’s modulus. It is a promising technique for measuring cervical tissue stiffness to predict preterm birth, but to-date has been semi-quantitative because the exact force applied to the cervix is difficult quantify. We aimed to develop a novel, fully-quantitative cervical elastography system to objectively quantify cervical tissue stiffness. A transvaginal ultrasound probe was modified with a pressure sensor at the tip to obtain real time synchronized pressure and tissue displacement measurements. Pressure and displacement were quantified to calculate the Young’s modulus (Figure1). This system was applied in a pilot prospective cohort study of women receiving prenatal care at a tertiary care center and enrolled in a longitudinal observational study with the larger aim of developing novel predictive methods for PTB. Generalized linear models were used to test changes in Young’s modulus (cervical stiffness) over advancing gestational age to determine if the tissue Young’s modulus decreases with advancing gestational age as expected with softening. A total 26 ultrasound elastography images from 12 patients were analyzed (9 term births and 3 preterm births). The Young’s modulus of cervical tissue tended to decrease with advancing gestational age (-0.65 Young’s modulus units per day) (Figure 2). We report a novel, sensor-based, fully quantitative cervical tissue elastography system using a modified transvaginal ultrasound probe for synchronized tissue deformation and pressure measurements. As expected, Young’s modulus tended to decrease over pregnancy as the cervix softens. This objective quantification of cervical tissue stiffness may be a promising tool for predicting preterm birth.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Acoustic radiation force impulse (ARFI) elastography to asses maternal and foetal structures in pregnant ewes.

The aim of this study was to evaluate the stiffness of foetal lungs, liver, kidneys and placentomes by acoustic radiation force impulse (ARFI) elastography in ovine and to correlate obtained findings with foetal development. Twenty-four ewes were included, and tissue stiffness of foetal lung, liver, kidney and placentome was measured beginning with 10th gestational week by qualitative-quantitative ARFI elastography. A total of 33 healthy lambs were born. Qualitative elastographic analysis permitted to classify maternal and foetal tissues elasticity in decreasing order as follows: placentome, kidney, liver and lung. Regarding quantitative ARFI elastography data, shear wave velocity (SWV) of foetal lung and liver varied. The lung SWV decreased gradually from the 16th to the 21st gestational week (R2 =0.80; p<0.001), while liver SWV increased gradually from the 14th to 21st gestational week (R2 =0.80; p<0.001). In contrast, the kidneys and placentomes SWV's remained constant through gestation (p=0.076; and 0.34). ARFI elastography was shown feasible for evaluation of maternal and foetal tissues stiffness in the ovine model. It can be used to demonstrate pulmonary and hepatic stiffness modifications during foetal development.

Ultrasound Elastography for Rapid, Real-time Detection of Localized Muscular Reaction in Malignant Hyperthermia-susceptible Pigs.

WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Halothane and caffeine induce excessive sarcoplasmic calcium liberation and skeletal muscle contracture in patients susceptible to malignant hyperthermia (MH) and are utilized for diagnosis in the in vitro contracture test. Intramuscular injection previously caused a marked local lactate increase in MH-susceptible but not in MH-nonsusceptible individuals in vivo. Using shear-wave elastography, this study evaluated localized changes in muscle stiffness after intramuscular injection of halothane and caffeine. Microdialysis probes were placed into the gracilis muscle of 16 pigs (9 MH-susceptible and 7 MH-nonsusceptible). After local injection of either halothane or caffeine in different concentrations, changes of tissue elasticity surrounding the probe were examined by quantitative shear-wave elastography. Local lactate concentrations were analyzed spectrophotometrically. Ultrasound elastography detected a temporary increase in local muscle rigidity in MH-susceptible but not in MH-nonsusceptible pigs after 2.5 and 5 vol% halothane and after 10, 40, and 80 mM caffeine, whereas there were no differences in the control groups (median [interquartile range] for maximum effect after 5 vol% halothane: MH-susceptible: 97 [31 to 148] vs. MH-nonsusceptible: 5 [-6 to 18] kPa; P = 0.0006; maximum effect after 80 mM caffeine: 112 [64 to 174] vs. -3 [-6 to 35] kPa; P = 0.0002). These effects were seen rapidly within 5 min. Local lactate concentrations were higher in MH-susceptible versus nonsusceptible pigs after 1 and 2.5 vol% halothane and 10, 40, and 80 mM caffeine (2.5 vol% halothane: MH-susceptible: 2.8 [1.9 to 4.4] vs. MH-nonsusceptible: 0.6 [0.6 to 0.7] mmol/l; P < 0.0001; 80 mM caffeine: 5.2 [4.1 to 6.3] vs. 1.6 [1.2 to 2.4] mmol/l; P < 0.0001). After 10 vol% halothane, rigidity and lactate levels were increased in both MH-susceptible and MH-nonsusceptible animals. This pilot study revealed shear-wave elastography as a suitable technique for real-time detection of altered tissue elasticity in response to pharmacologic stimulation. By considering the variability of these results, further test protocol optimization is required before elastography could serve as a minimally invasive MH diagnostic test.

Intraoperative Shear Wave Elastography vs. Contrast-Enhanced Ultrasound for the Characterization and Differentiation of Focal LiverLesions to Optimize Liver Tumor Surgery.

Assessment of intraoperative quantitative shear wave elastography (SWE) and contrast-enhanced ultrasound (CEUS) for the characterization of focal liver lesions (FLLs) during liver surgery using postoperative histopathological results as the gold standard. US data of 79 consecutive patients with 98 FLLs who underwent liver surgery between 08/2015 - 06/2017 were prospectively acquired and retrospectively analyzed. Multifrequency linear/T-shaped probes (6 - 9 MHz) were used to store cine loops of at least 5 s and images of B-mode, SWE and CEUS. The first CEUS loop was continuously documented over 1 min. in each case. Quantitative SWE analysis of FLLs was performed by placing 5 regions of interest to measure shear wave speed (m/s) and stiffness (kPa). CEUS was evaluated during the arterial, portal venous and late phase after i. v. bolus injections of 2.4 - 10 ml sulfur hexafluoride microbubbles. Postoperative histopathology after tumor resection or intraoperative biopsy was obtained to confirm findings of SWE and CEUS. Of 98 FLLs in 79 patients (mean age: 58 years sd ± 12y) 88 were malignant and 10 were benign ranging from 0.69 to 15.2 cm in size (mean: 2.8 cm, sd ± 2.25 cm). SWE characterized 73/88 FLLs correctly as malignant and 7/10 as benign using a cut-off value of 2.5 m/s/21.3 kPa (p < 0.0005). The sensitivity was 83 %, specificity 70 %, accuracy 82 %. CEUS could correctly identify 86/88 malignant and 8/10 benign FLLs. The sensitivity was 98 %, specificity 80 %, accuracy 96 %. SWE could correctly identify 2 malignant FLLs which CEUS falsely characterized as benign. Intraoperative CEUS and SWE are excellent tools for the highly accurate visualization, characterization and malignancy assessment of hepatic tumors during liver surgery.

Towards quantitative quasi-static ultrasound elastography using a reference layer for liver imaging application: A preliminary assessment

Changes in tissue elasticity are generally correlated with pathological phenomena. For example, diffuse liver disease progressively reduces the elasticity of the liver. Quasi-static elastography is popular in clinical applications to visualize regions with different relative stiffness. However, the limitation of this technique is that it provides only qualitative information. To overcome this, we investigate the use of a calibrated reference layer, sandwiched between the transducer and the tissue surface, to quantitatively image the unknown modulus of the examined tissue. The performance of the method was studied through simulations and experiments on agar-gelatin phantoms having Young's modulus within a range appropriate for the liver application. Furthermore, we explored the translational capability of the proposed method to work with existing commercially-available ultrasound scanners having elastography option. The Young’s modulus value of the phantom estimated from quantitative elastography in simulation and experiment was compared against the corresponding ground-truth modulus value obtained from COMSOL and Universal Testing Machine (UTM) results, respectively. The results obtained for the compressive elastic modulus of the underlying phantom using quasi-static ultrasound elastography was found to be within 6% and 11% in simulation and experiments, respectively, to the corresponding ground-truth values.

Quantitative Elastography of Rectal Lesions: The Value ofShear Wave Elastography in Identifying Benign and Malignant Rectal Lesions

We evaluate the value of shear wave elastography (SWE) in diagnosing benign and malignant rectal lesions. A total of 96 lesions were reviewed in this study; endorectal ultrasound (ERUS) and SWE examinations were performed before surgery in all cases. Elasticity parameters including mean elastographic index (Emean), maximum elastographic index (Emax) and minimum elastographic index (Emin) were analyzed. Correlations between elastographic parameters and histopathological results were studied. Inter-observer and intra-observer agreement was analyzed. Of the 96 rectal lesions, 72 were malignant and 24 were benign. Compared with ERUS, ERUS + SWE had higher sensitivity (93.0% vs. 88.9%), specificity (83.3% vs. 79.2%), positive predictive value (94.4% vs. 92.7%), negative predictive value (80.0% vs. 70.4%) and overall accuracy (90.6% vs. 86.4%). In receiver operating characteristic curve analysis, Emean and Emax had larger areas under the curve: 0.92 and 0.91, respectively. The optimal cutoff value was 61.3 kPa for Emean (sensitivity = 88.9%, specificity = 87.5%) and 63.4 kPa for Emax (sensitivity = 94.4%, specificity = 83.3%). We obtained κ values of 0.83 (95% confidence interval [CI]: 0.72–0.95) for ERUS and 0.90 (95% CI: 0.81–0.99) for ERUS + SWE of differential diagnosis in two observers. The intra-class correlation coefficients for intra-observer variability of stiffness (Emean) in malignant lesions, benign lesions, surrounding normal rectal wall in malignant lesions and surrounding normal rectal wall in benign lesions were 0.91 (95% CI: 0.86–0.94), 0.94 (95% CI: 0.88–0.97), 0.92 (95% CI: 0.88–0.95) and 0.89 (95% CI: 0.77–0.95), respectively. SWE is a promising tool that yields valuable quantitative data additional to that provided by ERUS examination in rectal lesions. The cutoff value 61.3 kPa for Emean may serve as a complementary tool in diagnosis of rectal lesions.

Grayscale ultrasonic and shear wave elastographic characteristics of the Achilles’ tendon in patients with familial hypercholesterolemia: A pilot study

ObjectiveTo investigate the feasibility of grayscale ultrasound and quantitative shear wave elastography (SWE) for assessing the image features and stiffness of the Achilles tendon in patients with familial hypercholesterolemia (FH) compared with healthy controls. MethodsA total of 38 Achilles tendons from healthy control participants and 94 from patients with FH were examined with grayscale ultrasound and SWE. Each Achilles tendon examination was performed on 3 different segments (proximal, middle, and distal). The thickness, grayscale image features and elasticity modulus of each segment was measured on longitudinal views. ResultsIn Achilles tendons of healthy control participants, the thicknesses of the proximal, middle, and distal segments were (4.46 ± 0.68) mm, (5.41 ± 1.01) mm, and (4.41 ± 0.57) mm, respectively. The grayscale features were diffusely hypoechoic with parallel linear hyperechoic striations. The mean elasticity modulus of the proximal, middle, and distal sites was (418.08 ± 43.13) kPa, (425.78 ± 47.14) kPa, and (407.79 ± 38.74) kPa, respectively. In the FH group, the thicknesses of the proximal, middle, and distal segments were (7.65 ± 3.09) mm, (11.46 ± 4.84) mm, and (8.14 ± 2.90) mm, respectively. The grayscale features were hypoechoic with linear hyperechoic disordered fibre distribution (92/94). Two of 94 Achilles tendons had considerable focal hypoechogenicity. Seventeen of 94 Achilles tendons had calcifications. In the FH group, the mean elasticity modulus of the proximal, middle, and distal segments were (294.86 ± 58.13) kPa, (280.93 ± 63.58) kPa, and (282.41 ± 56.47) kPa, respectively. Statistically significant differences were found between the Achilles tendons of healthy control participants and FH patients in the thicknesses and mean elasticity modulus at the proximal, middle and distal segments of the Achilles tendons (all P < 0.001). ConclusionsOur results suggest that the grayscale features and SWE characteristics of the Achilles tendon provided complementary biomechanical information for quantitative assessment the Achilles tendon in patients with FH.

Acoustic radiation force impulse elastography of the eyes of brachycephalic dogs

ABSTRACT Eyes from brachycephalic dogs were studied by acoustic radiation force impulse (ARFI) elastography to establish quantitative and qualitative reference values related to the shape and rigidity of some ocular structures. Eighty-four eyes from 42 adult brachycephalic dogs were included in this study. Animals were subjected to physical, laboratory, and ophthalmic examinations. Following confirmation of good health, the dogs were subjected to ultrasonography and ARFI elastography, emphasizing the optic nerve, ciliary body, and lens. On qualitative elastography, homogeneous characteristics were observed on the ciliary body and optic nerve. Aqueous and vitreous humors were visualized as mosaic-like images. Quantitative elastography showed the mean optic nerve shear wave velocity (SWV) was 1.01±0.27m/s, temporal ciliary body was 0.91±0.24m/s, and nasal ciliary body was 0.91±0.3m/s. The SWV of the lens values were out of range, this value was not detectable by this software. Elastography has proved to be a non-invasive procedure and feasible in dogs. The establishmentof the parameters of degree of rigidity of ocular structures will serve as a baseline for animals with eye disorders. Results may be extrapolated to primary research on the applicability of ARFI in the evaluation of ocular bulb in humans.

Endoscopic ultrasound elastography in the diagnosis of pancreatic masses: A meta-analysis

Background and aimsEndoscopic ultrasound (EUS) elastography is a novel non-invasive technique that can be used for distinguishing benign from malignant pancreatic masses. However, the studies have reported widely varied sensitivities and specificities. A meta-analysis was performed to assess the performance of EUS elastography for the differentiation of benign and malignant pancreatic masses. MethodsAll the eligible studies were searched by PubMed, Medline, Embase, and the Cochrane Library. Sensitivity, specificity, positive likelihood ratio (LR), negative LR, and area under the curve (AUC) were calculated to examine the accuracy. ResultsA total of nineteen studies which included 1687 patients were analyzed. The pooled sensitivity and specificity for the diagnosis of malignant pancreatic masses were 0.98 (95% confidence interval [CI] 0.96–0.99) and 0.63 (95% CI 0.58–0.69) for qualitative EUS elastography, 0.95 (95% CI 0.93–0.97) and 0.61 (95% CI 0.56–0.66) for quantitative EUS elastography, respectively. The positive and negative LR were 2.60 (95% CI 1.84–3.66) and 0.05 (95% CI 0.02–0.10) for qualitative EUS elastography, 2.64 (95% CI 1.82–3.82) and 0.10 (95% CI 0.06–0.16) for quantitative EUS elastography, respectively. The summary diagnostic odds ratio (DOR) and the AUC were 60.59 (95% CI 28.12–130.56) and 0.91 (Q* = 0.842) for qualitative EUS elastography, 30.09 (95% CI 15.40–58.76) and 0.93 (Q* = 0.860) for quantitative EUS elastography. ConclusionsOur meta-analysis shows that both qualitative and quantitative EUS elastography have high accuracy in the detection of malignant pancreatic masses, which could be used as a valuable complementary method to EUS-FNA for the differentiation of pancreatic masses in the future.

Quantitative Optical Coherence Elastography for Robust Stiffness Assessment.

We demonstrated the capability of quantitative optical coherence elastography (qOCE) for robust assessment of material stiffness under different boundary conditions using the reaction force and displacement field established in the sample.

Differentiating the acute phase of gout from the intercritical phase with ultrasound and quantitative shear wave elastography.

To evaluate the value of ultrasound (US) in differentiating the acute phase of gout from the intercritical phase, particularly using shear wave elastography (SWE). 57 gout patients were prospectively enrolled and divided into acute phase and intercritical phase groups. The patients underwent US and SWE examinations for the first metatarsophalangeal joints with the same protocol. Maximum synovial thickness was measured. US features were reviewed by two radiologists independently. The maximum (Emax) and mean (Emean) elastic moduli of synovium were calculated. Diagnostic performances of US, SWE and combined US and SWE were evaluated. US findings demonstrated that the colour Doppler flow signal grade in the acute phase was higher than that in the intercritical phase (p = 0.001), whereas no differences were found for B-mode US features between the two groups (all p > 0.05). For SWE, Emax and Emean were significantly higher in the intercritical phase than in the acute phase (both p < 0.001). The areas under the receiver operating characteristic curve (AUROCs) were 0.494-0.553 for B-mode US, 0.735 for colour Doppler US (CDUS), 0.887 for Emax and 0.882 for Emean. The combination of CDUS and SWE increased the AUROC, sensitivity and accuracy significantly in comparison with CDUS alone (all p < 0.001). However, the combined set did not show stronger diagnostic performance in comparison with SWE alone. SWE increases the diagnostic performance in differentiating the acute phase of gout from the intercritical phase in comparison with conventional US. • Colour Doppler flow signal grade is higher in acute phase of gout than in intercritical phase. • SWE demonstrates that synovium stiffness is higher in intercritical phase of gout than in acute phase. • SWE increases diagnostic performance in differentiating acute phase of gout from intercritical phase in comparison with conventional US.

Quantitative transrectal shear wave elastography undergoing salvage extraperitoneal laparoscopic radical prostatectomy following failed radiotherapy.

To evaluate pre-surgical quantitative transrectal shear wave elastography (SWE) in the detection and characterisation of radioresistant prostate cancer. Twelve men with recurrent prostate cancer following external beam radiotherapy were included in a prospective protocol-driven study. All underwent MR imaging and quantitative shear wave elastographic assessment of recurrent disease prior to salvage laparoscopic radical prostatectomy procedures. Images were used to construct 3D mold printing and histopathological processing of surgical specimen. Statistical analyses including ROC were generated using software programmes. There were 48 cancer foci identified on final histopathology using patient-specific mold-based approach in 12 patients. Mean number of lesion was 3.4 (range 2-4). Quantitative transrectal SWE showed a sensitivity and specificity 0.77 (95% CI 0.627-0.880) and 0.82 (95% CI 0.642-0.942), respectively. The diagnostic accuracy increased with increasing size of the lesions with overall AUC of 0.89. In our series, quantitative transrectal SWE showed a good diagnostic accuracy in the detection and characterisation of recurrent prostate cancer following failed radiotherapy treatment. These findings may help in targeting biopsies or future focal treatment options.

Tumor stiffness measured by quantitative and qualitative shear wave elastography of breast cancer.

To correlate clinicoradiologic and pathological features of breast cancer with quantitative and qualitative shear wave elastographic parameters. 82 breast cancers in 75 patients examined by B-mode ultrasound and shear wave elastography (SWE) were included. SWE parameters including quantitative factors [maximum elasticity (Emax), mean elasticity (Emean), elasticity ratio (Eratio) and standard deviation (SD)] and qualitative factor (color pattern) were correlated with clinicoradiologic and pathological features using univariate and multivariate linear regression analyses. Presence of symptoms and larger tumor size on ultrasound were significantly associated with higher Emax, Emean, Eratio, and SD (all p < 0.05) on univariate analysis. Older age was significantly correlated with higher Emax and Emean (p = 0.026, 0.018). Lymphovascular invasion and larger pathologic size were significantly associated with higher Emax (p = 0.036, 0.043) and SD (p < 0.001, 0.019). No immunohistochemical biomarkers were significantly correlated with SWE parameters. There was no significant correlation between color pattern and any variable. Multivariate logistic regression analysis showed that the symptom, tumor size on ultrasound and lymphovascular invasion were independent factors that influenced the SWE values. Tumor stiffness as measured by SWE and B-mode ultrasound could help predict cancer prognosis. Advances in knowledge: Clinicoradiologic factors had correlation with quantitative and qualitative SWE parameters. Using SWE parameters and B-mode ultrasound, we can predict breast cancer prognosis.

Performance Characteristics of Transrectal Shear Wave Elastography Imaging in the Evaluation of Clinically Localized Prostate Cancer: A Prospective Study

We tested the diagnostic accuracy of shear wave elastography to detect and phenotypically characterize prostate cancer compared with whole mount radical prostatectomy histopathology. In this prospective, protocol driven, diagnostic accuracy study 212 consecutive men undergoing laparoscopic radical prostatectomy for clinically localized prostate cancer were recruited. Quantitative stiffness data on the prostate gland were obtained in each patient using an endocavitary transrectal transducer before laparoscopic radical prostatectomy. Those data were compared with a detailed histopathological examination of the radical prostatectomy specimen using 3-dimensional printing mold based technology to ensure an improved image histology orientation. ROC curves were assessed between the groups. Quantitative stiffness data estimated in kPa were significantly higher in malignant compared with benign areas. At a cutoff of 82.6 kPa the sensitivity and specificity of shear wave elastography were 96.8% and 67.8%, respectively (p<0.01). Significant differences were observed for different cancer grades with the Young moduli, including 91.6, 102.3 and 131.8 kPa for low grade (Gleason score 6), intermediate grade (Gleason score 7) and high grade (Gleason score 8 or greater) prostate cancer, respectively (p <0.05). Shear wave elastography also detected capsular breaches with significant prediction of prostate cancer pathological staging. Potential limitations include selection bias and study being single center site. Quantitative shear wave elastography via the transrectal approach accurately detected cancer foci and revealed significant differences between cancerous and benign tissue. Moreover, this technique can be used to reliably phenotype prostate cancer aggressiveness.

Assessment of the hardness of salivary gland lesions in patients with Sjögren′s syndrome by real-time shear wave elastography

Objective To investigate the clinical value of the real-time shear wave elastography(RT-SWE) in the assessment of salivary gland lesions by measuring the hardness of parotid gland and submaxillary gland in patients with Sjogren′s syndrome (SS). Methods Forty patients with SS were chosen as SS group, and 35 age and gender matched healthy volunteers were chosen as control group. The patients were divided into mild SS group (n=18) and severe SS group (n=22) according to the decrease of uptake and secretion of salivary gland in Salivary gland scintigraphy. The Supersonic AixPlorer real-time quantitative diagnostic shear wave elastography was used to detect the parotid gland and submaxillary gland in 35 healthy volunteers and 40 patients. The RT-SWE elasticity indices of mean (Emean) was obtained and draw the SWE technology in the diagnosis of mild and severe SS patients with parotid and submandibular glands of the ROC curves. Results ①There was no significant difference in the Emean of left and right glands among the three groups (all P>0.05). The Emean of parotid gland and submaxillary gland in patients with SS was higher than that in control group, especially in the severe SS group (all P<0.05). ②The cutoff value, sensitivity, specificity and the area under ROC for Emean with SWE diagnosing the parotid gland lesions of mild SS were 7.75 kPa, 94.4%, 97.1% and 0.998, and those in severe SS were 10.65 kPa, 90.9%, 97.1% and 0.999, respectively. The cutoff value, sensitivity, specificity and the area under ROC for Emean with SWE diagnosing the the submaxillary glands lesions of mild SS were 8.15 kPa, 100%, 91.4% and 0.998, and those in severe SS were 10.40 kPa, 95.5%, 88.6%and 0.994, respectively. Conclusions RT-SWE can be successfully applied to assess parotid gland and submaxillary gland′s hardness in patients with SS, and provide a new method for the clinical evaluation of salivary gland diffuse lesions. Key words: Shear wave elastography; Sjogren syndrome; Elastic Modulus; Parotid gland; Submaxillary gland

Quantitative Elastography Methods in Liver Disease: Current Evidence and Future Directions.

Chronic liver diseases often result in the development of liver fibrosis and ultimately, cirrhosis. Treatment strategies and prognosis differ greatly depending on the severity of liver fibrosis, thus liver fibrosis staging is clinically relevant. Traditionally, liver biopsy has been the method of choice for fibrosis evaluation. Because of liver biopsy limitations, noninvasive methods have become a key research interest in the field. Elastography enables the noninvasive measurement of tissue mechanical properties through observation of shear-wave propagation in the tissue of interest. Increasing fibrosis stage is associated with increased liver stiffness, providing a discriminatory feature that can be exploited by elastographic methods. Ultrasonographic (US) and magnetic resonance (MR) imaging elastographic methods are commercially available, each with their respective strengths and limitations. Here, the authors review the technical basis, acquisition techniques, and results and limitations of US- and MR-based elastography techniques. Diagnostic performance in the most common etiologies of chronic liver disease will be presented. Reliability, reproducibility, failure rate, and emerging advances will be discussed. © RSNA, 2018 Online supplemental material is available for this article.