Semiquantitative strain elastography of liver masses

Diagnostic performance of ultrasound elastography in differentiating hepatocellular carcinoma and intrahepatic cholangiocarcinoma: a systematic review and meta-analysis

PURPOSE

To evaluate the diagnostic value of ultrasound elastography (USE) for characterizing hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC).

METHODS

The protocol was pre-registered a priori at ( https://osf.io/namvk/ ). Using PubMed, Web of Science, Embase, and Cochrane Library, we found studies up to April 20, 2024 by searching HCC, ICC, and USE as keywords. Parameters of USE were directly compared between HCC and ICC patients using random-effects bivariate model on STATA 17.0, MedCalc 20.0, and Psychometrica. Trim & fill method and sensitivity analysis were also performed.

RESULTS

Eighteen studies were included with 1057 patients, consisting of 863 HCC lesions, 188 ICC lesions, and 6 mixed lesions. The pooled Emean values of HCC and ICC were 28.3 (CI = 19.8 to 36.8) and 44.0 (CI = 20.9 to 67.2). HCC tumors were 34.3% softer than ICC while peritumoral tissue in HCC lesions was 75% stiffer than ICC lesions based on Emean. The strain value index (tumoral-to-peritumoral ratio) in HCC patients was 49.4% less than that of ICC patients. USE demonstrated a pool sensitivity of 87% (CI = 73-95%), specificity of 82% (CI = 65-92%), positive likelihood ratio of 4.8 (CI = 2.2 to 10.3), negative likelihood ratio of 0.16 (CI = 0.07 to 0.37), and diagnostic odds ratio of 31 (CI = 7 to 127) in differentiation of ICC from HCC.

CONCLUSION

By evaluating tumoral and pre-tumoral stiffness, along with strain value index, USE may provide a valuable quantitative diagnostic tool for accurately differentiating HCC and ICC.

Unveiling the potential of strain elastography in perihilar cholangiocarcinoma biopsies

PURPOSE

This study was conducted to investigate the effectiveness of strain elastography in guiding precise and sufficient tissue sampling for perihilar cholangiocarcinoma (CCA) biopsies.

METHODS

Our retrospective analysis included 23 liver biopsies conducted between March 2019 and July 2022 for suspected perihilar CCA. An experienced radiologist performed the biopsies via an ultrasound machine with elastography configuration. Tissue stiffness color maps were used for guiding when the biopsies were performed. Strain index value calculations were made by radiologists on recorded images.

RESULTS

Patient demographics revealed a mean age of 65.17 ± 9.25 years, with a gender distribution of six females and 17 males. Gray-scale examinations unveiled diverse echogenic characteristics in liver lesions. Elastography-guided biopsies demonstrated no need for repeats, while gray-scale biopsies necessitated re-biopsy in four patients, resulting in cholangiocarcinoma diagnosis (P = 0.037). Strain index values showcased strong inter- and intra-observer agreements (P < 0.001). Notably, no post-biopsy complications emerged in either study group.

CONCLUSION

The diagnostic advantage of elastography, particularly in enhancing accuracy in challenging isoechoic lesions, was demonstrated, although the substantial overlap between strain index values of benign and malignant liver masses limits clinical usefulness of this technique.

Resonance, Velocity, Dispersion, and Attenuation of Ultrasound-Induced Shear Wave Propagation in Blood Clot In Vitro Models

OBJECTIVE

Improve the characterization of mechanical properties of blood clots. Parameters derived from shear wave (SW) velocity and SW amplitude spectra were determined for gel phantoms and in vitro blood clots.

METHODS

Homogeneous phantoms and phantoms with gel or blood clot inclusions of different diameters and mechanical properties were analyzed. SW amplitude spectra were used to observe resonant peaks. Parameters derived from those resonant peaks were related to mimicked blood clot properties. Three regions of interest were tested to analyze where resonances occurred the most. For blood experiments, 20 samples from different pigs were analyzed over time during a 110-minute coagulation period using the Young modulus, SW frequency dispersion, and SW attenuation.

RESULTS

The mechanical resonance was manifested by an increase in the number of SW spectral peaks as the inclusion diameter was reduced (P < .001). In blood clot inclusions, the Young modulus increased over time during coagulation (P < .001). Descriptive spectral parameters (frequency peak, bandwidth, and distance between resonant peaks) were linearly correlated with clot elasticity values (P < .001) with R2  = .77 for the frequency peak, .60 for the bandwidth, and .48 for the distance between peaks. The SW dispersion and SW attenuation reflecting the viscous behavior of blood clots decreased over time (P < .001), mainly in the early stage of coagulation (first minutes).

CONCLUSION

The confined soft inclusion configuration favored SW mechanical resonances potentially challenging the computation of spectral-based parameters, such as the SW attenuation. The impact of resonances can be reduced by properly selecting the region of interest for data analysis.

Comparison of the fibrosis degree using acoustic radiation force impulse elastography and diffusion-weighted magnetic resonance imaging in chronic hepatitis cases

OBJECTIVE

The aim of this study was to investigate the correlation of fibrosis stages in cases of chronic hepatitis by comparing shear wave elastography and diffusion-weighted magnetic resonance imaging.

METHODS

A total of 46 chronic hepatitis patients with an age range of 20-50 years were classified into three groups based on their fibrosis stages. Comparison group 1: the presence of fibrosis (S0 and S1≤); comparison group 2: the presence of significant fibrosis (≤S2 and S3≤); and comparison group 3: the presence of cirrhosis (≤S4 and S6). Shear wave velocities were measured by acoustic radiation force impulse elastography. Diffusion-weighted magnetic resonance imaging was performed on a 3.0 Tesla MRI device.

RESULTS

In comparison group 1 (S0 and S1≤), the area under the curve, sensitivity, and specificity of acoustic radiation force impulse values were 0.784, 87, and 60%, respectively, while these values were 0.718, 80, and 66%, respectively, for apparent diffusion coefficient . In comparison group 2 (≤S2 and S3≤), the area under the curve, sensitivity, and specificity of acoustic radiation force impulse values were 0.917, 80, and 86%, respectively, and the apparent diffusion coefficient values were 0.778, 90, and 66%, respectively. In comparison group 3, the area under the curve, sensitivity, and specificity of acoustic radiation force impulse values were 0.977, 100, and 95%, respectively. There was no statistically significant difference between the apparent diffusion coefficient values of the cases in the three groups (p=0.132).

CONCLUSION

Noninvasive methods are gaining importance day by day for staging hepatic fibrosis. Acoustic radiation force impulse elastography was evaluated as a more reliable examination than diffusion-weighted magnetic resonance imaging in revealing the presence of fibrosis, determining significant fibrosis, and diagnosing cirrhosis.

Usability of Real-Time Elastography for the Diagnosis of Primary Open Angle and Pseudoexfoliation Glaucoma

OBJECTIVES

This study aims to investigate real-time elastography (RTE) use in the evaluation of the optic nerve head (ONH) and peripapillary structures for the diagnosis of primary open angle (POAG) and pseudoexfoliation (PEX) glaucoma.

METHODS

This case-controlled study included 30 patients with POAG, 30 patients with PEX glaucoma, and 30 age-matched control subjects. All of the participants underwent comprehensive ophthalmological examinations covering vessel density of optic nerve and retinal nerve fiber layer (RNFL) thickness measurements with optical cohorence tomography angiography and mean deviation (MD) measurements with Humphrey II Perimetry Visual Field Analyzer. In vivo evaluation of the biomechanical properties of the ONH and peripapillary structures were performed with RTE in all participants.

RESULTS

We observed higher ratios of orbital fat to optic nerve head (ROFON) values (P = .008) and strain ratios of orbital fat to scleral-choroidal-retinal complex (ROFSCR) values (P = .004) in the POAG group compared with PEX glaucoma group and higher ROFON (P = .012) and ROFSCR values (P = .004) in PEX glaucoma group than the control group. ROFON and ROFSCR values were positively correlated with glaucoma duration and negatively correlated with MD, radial peripapillary vessel density (RPCVD), and inside disc vessel density in both glaucoma groups (P < .005; only in the PEX glaucoma group for MD and ROFSCR, P = .445).

CONCLUSION

Determining the biomechanical properties of ONH and peripapillary structures with RTE in glaucomatous eyes may offer a new perspective on the diagnosis and follow-up of the progression of the disease.

Ultrasound Elastography in the Differentiation of Simple Cyst and Type I Hydatid Cyst of the Liver

ABSTRACT

Hydatid cyst (HC) is a parasitic disease that is endemic particularly to the sheep-breeding regions of the world, our country included. Given their propensity to materialize most commonly in the liver, our study evaluates the value of ultrasound elastography in the differential diagnosis of simple cyst and type I HCs of the liver.The study involved a total of 73 cysts (22 simple cysts, 51 type I HCs) that were removed using the puncture aspiration injection reaspiration technique between 2016 and 2018. All measurements were made using a Siemens ACUSON S2000 (Siemens Healthcare, Erlangen, Germany) device with a 4-MHZ 4C1 convex probe, an acoustic radiation force impulse elastography procedure, and a Virtual Touch IQ option. The difference between the mean shearwave elastography (SWE) values of both groups was analyzed with an independent t test.Of the 70 patients involved in the study, 29 were female and 41 were male, with a mean ± SD age of 38.85 ± 17.62 years (range, 5-82 years). Upon the examination of the 22 simple cysts and the 51 HCs, the mean ± SD SWE values were found to be 2.6 ± 0.96 (0.96-4.25) and 2.8 ± 1.69 (0.66-4.84), respectively. No statistically significant difference was identified between the SWE values of type I HCs and simple cysts (P > 0.005).Although HCs and simple cysts had similar radiological appearances, and a relative difference was noted in the differentiation of the elastographic measurements, this difference was not statistically significant. Accordingly, more comprehensive and various studies are needed.

Shear wave elastography in varicocele patients: Prospective study to investigate correlation with semen parameters and histological findings

AIMS

Shear wave elastosonography (SWE) is a non-invasive ultrasound imaging modality used to assess the mechanical properties of tissues such as rigidity and elasticity. In this prospective study, we investigated the effect of laparoscopic varicocelectomy on the elasticity, degree of fibrosis and function of the testes through SWE and we evaluated the correlation with semen parameters and histology findings.

METHODS

Male patients with monolateral left varicocele and progressive alteration of the semen quality were enrolled prospectively. Patients were evaluated before varicocelectomy, 3 and 6 months after surgery with semen analysis, ecocolordoppler US and SWE. In all patients, a left testicular biopsy was performed at the time of varicocelectomy and it was repeated after 6 months in 55% of patients in order to investigate the histological findings and to correlate with SWE results.

RESULTS

The study was conducted on 82 patients. SWE showed a statistically significant difference between left and right testicles. Three months after surgery the mean left testicular volume increased, mean left SWE features decreased, and sperm count increased (P values < .0001). The SWE parameters, testicular volume and semen analysis values showed a statistically significant positive correlation between the pre and postoperative results (P value < .0001). The histological alterations were significantly changed 6 months postoperative with a complete morphology recovery in accordance with SWE results.

CONCLUSIONS

SWE showed a statistically significant positive correlation with testicular volume, semen analysis and histological findings. This study represents the first investigation that correlates the varicocele, the testis volume, the quality of the seminal fluid ant the histological findings with the ultrasound and SWE values.

Evaluation of Optic Nerve Head Biomechanical Properties in Pseudoexfoliation Glaucoma with Real-time Elastography

PURPOSE

To investigate the biomechanical properties of the optic nerve head in patients with Pseudoexfoliation (PEX) glaucoma using Real-time Elastography (RTE) and to compare these results with those of Primary Open Angle Glaucoma (POAG) patients and healthy subjects.

METHODS

Twenty eyes of 20 PEX glaucoma patients (PEX group), 20 eyes of 20 POAG patients (POAG group), and 20 eyes of 20 healthy subjects (control group) were enrolled in this prospective study. The strain Ratios of Orbital Fat to Optic Nerve head (ROFON) and lateral rectus muscle to optic nerve head (RLRON) were determined. Comparisons were performed using Chi-square, Kruskal Wallis, Mann-Whitney U, and One-way ANOVA tests.

RESULTS

The strain ratios of orbital fat to optic nerve head were 2.34, 6.85 and 1.76 in PEX glaucoma, POAG, and control groups, respectively (p<0.001). The strain ratios of the lateral rectus muscle to the optic nerve head were 0.51, 0.82, and 0.55 in PEX glaucoma, POAG, and control groups, respectively (p=0.256).

CONCLUSION

The strain ratios of orbital fat to optic nerve head were different in PEX glaucoma patients than in POAG and control groups. RTE can provide biomechanical assessment of the optic nerve head in a non-invasive, quick, easily accessible, and user-friendly manner.

Interfascicular Gliding Dysfunction Relation with Focal Neuropathy in Diabetic Patients with Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS), a common neuropathy of the upper limb, is highly prevalent in diabetic patients. Recent findings indicate that changes in median nerve elasticity and its gliding characteristics may contribute to the development of CTS. Normally, each nerve should be able to adapt to the positional changes by passive movement relative to the surrounding tissues. This ability is provided by a gliding apparatus around the nerve trunk in the surrounding soft tissue. The fascicles of nerve trunks can also glide against each other (interfascicular gliding). Sonoelastography indicates that nerve elasticity is decreased in patients with CTS compared to healthy patients. Moreover, decreased nerve elasticity in diabetes mellitus type II is associated with increased neuropathy, especially in peripheral nerves. Biomechanical factors, oxidative stress, and microvascular defects are also observed in diabetic neuropathy and account for different complications. A reduction in the elasticity of peripheral nerves may be related to decreased interfascicular gliding because of the biomechanical changes that occur in neuropathy. Surgical treatments, including nerve release and reduction of carpal tunnel pressure, improve peripheral gliding but do not resolve disease symptoms completely. According to the evidence, interfascicular gliding dysfunction is the most important factor in the pathogenesis of CTS in diabetic patients. Available evidence suggests that biomechanical variations affect interfascicular gliding more than peripheral gliding in diabetic patients. Decreased nerve elasticity is strongly correlated with decreased interfascicular gliding. It is further hypothesized that the concurrent use of antioxidants and pharmacological treatment (neuroprotection) such as alpha lipoic acid with carpal tunnel release in diabetic patients may alleviate the interfascicular gliding dysfunction and improve median neve elasticity. Decreased nerve elasticity and interfascicular gliding dysfunction play significant roles in the pathogenesis of CTS in diabetic patients.

Diagnosis of liver tumors by multimodal ultrasound imaging

To investigate the diagnostic value of multimodal ultrasound imaging composed of conventional ultrasonography (US), contrast-enhanced ultrasonography (CEUS), and shear wave elastography (SWE) for liver tumors.Between October 2017 and October 2019, US, CEUS, and SWE examinations of a total of 158 liver tumors in 136 patients at The First Affiliated Hospital of Nanchang University were performed. The histopathological or imaging diagnostic results were used as controls to evaluate the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of US, CEUS, SWE, and multimodal ultrasound imaging, which combines these 3 modes, in the differential diagnosis of benign and malignant liver tumors.Among the 158 tumors, there were 64 benign tumors, including 55 cases of hepatic hemangioma, 3 cases of focal nodular hyperplasia of the liver, 4 cases of hepatic cyst, and 2 cases of focal nonuniform distribution of fat in the liver. There were 94 malignant tumors, including 32 cases of hepatocellular carcinoma, 22 cases of intrahepatic cholangiocellular carcinoma, 29 cases of metastatic liver cancer, and 11 cases of dysplastic nodules in cirrhotic liver. In the diagnosis of benign and malignant liver tumors, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 82.56%, 68.06%, 75.96%, 75.53%, and 76.56% for US; 92.39%, 86.36%, 89.87%, 90.43%, and 89.06% for CEUS; 87.14%, 76.81%, 82.91%, 82.98%, and 82.81% for SWE; and 97.85%, 95.38%, 96.83%, 96.81%, and 96.88% for multimodal ultrasound imaging, respectively. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were all significantly higher for multimodal ultrasound imaging than those values for US, CEUS, and SWE (all P < .05). The areas under the receiver operating characteristic curve for US, CEUS, SWE, and multimodal ultrasound imaging in the diagnosis of benign and malignant liver tumors were 0.760, 0.897, 0.829, and 0.968, respectively.US, CEUS, and SWE all have diagnostic value in the diagnosis of benign and malignant liver tumors. Multimodal ultrasound imaging could significantly increase the accuracy of the diagnosis of benign and malignant liver tumors and has higher value for clinical application.

Elastography for characterization of focal liver lesions: current evidence and future perspectives

Focal liver lesions (FLLs) are a common finding during routine abdominal ultrasound (US). The differential diagnosis between diverse types of FLLs, especially between benign and malignant ones, is extremely important and can often be particularly challenging. Radiological techniques with contrast administration and/or liver biopsy are mostly necessary for establishing diagnosis, but they have several contraindications or complications. Due to limitations of these tools, there is urgent and still unmet need to develop a first line, non-invasive and simple method to diagnose FLLs. Elastography is an US-based imaging modality that provides information about the physical parameter corresponding to the tissue stiffness and can be considered a virtual biopsy. Several elastographic approaches have been developed, such as transient elastography, strain imaging and share wave imaging, which include point shear wave elastography and 2D shear wave elastography. These tools are already in use for evaluating liver fibrosis and in the assessment of focal lesions in other organs, like breast and thyroid gland. This review aims to assess the current evidence of different techniques based on elastography in the setting of FLLs, in order to evaluate accuracy, limitations and future perspectives. In particular, we focused on two contexts: the ability of discriminating between benign and malignant lesions, especially hepatocellular carcinoma and liver metastasis, and the surveillance after percutaneous therapy. This could have a high clinical impact making elastography crucial to identify the appropriate management of FLLs.

Is ultrasound elastography adding value in diagnosis of focal hepatic lesions? Our experience in a single-center study

Background

The aim of this study was to assess the use of ultrasound elastography in differentiating hepatic lesions in order to increase the sensitivity and specificity of grey-scale ultrasound.

Methods

This study included 104 patients who were referred to the radiology department at Alexandria Main University Hospital for focal hepatic lesions detected by grey-scale ultrasound and were recommended to undergo further evaluation by ultrasound elastography. All studied patients were subjected to the following: (1) grey-scale ultrasound and ultrasound elastography using semiquantitative technique and (2) triphasic MDCT of the liver. MRI was done in 11 patients with malignant lesions; further confirmation with histopathological assessment was conducted.

Results

Benign lesions showed a low strain ratio, while malignant lesions showed a high strain ratio. The mean ratio in the benign lesions was 1.08 ± 0.40, while the mean ratio in the malignant lesions was 4.14 ± 1.25. The cut-off value used to diagnose the malignant lesions and differentiate these lesions from the benign lesions was 1.7, which had a sensitivity of 100%, specificity of 93.10%, PPV of 97.40% and NPV of 100%.

Conclusion

Ultrasound elastography is a promising non-invasive, non-contrast technique that can be added to routine grey-scale sonographic examinations of the liver to characterize hepatic lesions.

Strain elastography as an early predictor of long-term prognosis in patients with locally advanced cervical cancers treated with concurrent chemoradiotherapy

OBJECTIVE

To explore the value of strain elastography as an early predictor of long-term prognosis in patients with locally advanced cervical cancers treated with concurrent chemoradiotherapy (CCRT).

METHODS

Strain elastography examinations were performed on 45 patients with locally advanced cervical cancers at 3 time points: prior to CCRT, and at 1 and 2 weeks after the start of CCRT. The maximum tumor diameter (D_max), strain ratio (SR), and their percentage changes (ΔD_max and ΔSR) were calculated to predict long-term prognosis. Based on the results of physical examinations, Papanicolaou test, and pelvic magnetic resonance imaging, we classified patients into two groups: responders (complete remission) and non-responders (sustained disease, recurrence, or death).

RESULTS

After a median follow-up of 30 months (range, 12-36 months), 36 of 45 (80%) patients were disease free. The D_max as well as ΔD_max at 2 weeks during CCRT was able to predict the responder outcomes, with an area-under-the-curve (AUC) of 0.733 and 0.731, respectively. Furthermore, significant differences in SR and ΔSR at 1 and 2 weeks during therapy were shown between the responder and non-responder groups (all p < 0.05), and ΔSR at 2 weeks during CCRT presented with the highest AUC (0.91), yielding 88.9% sensitivity and 88.9% specificity with a selected cutoff value.

CONCLUSIONS

Strain elastography may be useful as an early predictor of long-term outcomes after CCRT for patients with cervical cancer.

KEY POINTS

• The D _maxas well as ΔD _maxat 2 weeks during CCRT can predict the responder outcomes. • The elastography parameters (SR and ΔSR) exhibited predictive values of favorable response after therapy initiation. • ΔSR at 2 weeks during CCRT held the best predictive value for the responder outcomes.

Diagnostic effect of shear wave elastography imaging for differentiation of malignant liver lesions: a meta-analysis

Background

Shear wave elastography (SWE) imaging have been proposed for characterization of focal liver lesions. We conducted a meta-analysis to evaluate the accuracy and clinical utility of SWE imaging for differentiation of malignant and benign hepatic lesions.

Methods

PubMed, Embase, Web of Science, and the Cochrane Library were systematically reviewed to search for studies published between January 1, 1990, and November 30, 2018. The studies published in English relating to the evaluation the diagnostic accuracy of SWE imaging for distinguishing malignant and benign liver lesions were retrieved and examined for pooled sensitivity, specificity, likelihood ratios, and diagnostic odds ratios, using bivariate random-effects models. The hierarchical summary receiver operating characteristic (HSROC) curve was estimated to assess the SWE imaging accuracy. The clinical utility of SWE imaging for differentiation of malignant liver lesions was evaluated by Fagan plot.

Results

A total of 15 studies, involving 1894 liver lesions in 1728 patients, were eligible for the meta-analysis. The pooled sensitivity and specificity for identification of malignant liver lesions were 0.82 (95% CI: 0.77–0.86) and 0.82 (95% CI: 0.76–0.87), respectively. The AUC was 0.89 (95% CI: 0.86–0.91). When the pre-test probability was 50%, after SWE imaging measurement over the cut-off value (positive result), the corresponding post-test probability for the presence of malignant liver lesions was 82%; the post-test probability was 18% after negative measurement.

Conclusions

SWE imaging showed high sensitivity and specificity in differentiating malignant and benign liver lesions and may be promising for noninvasive evaluation of liver lesions.

Trial registration

The review was registered in the International Prospective Register of Systematic Reviews (PROSPERO): CRD42018104510.

Electronic supplementary material

The online version of this article (10.1186/s12876-019-0976-2) contains supplementary material, which is available to authorized users.

Comparison of median nerve stiffness with and without rheumatoid arthritis by ultrasound real-time tissue elastography: A propensity score matching study

Objectives: This study aimed to compare median nerve stiffness measured by ultrasound real-time tissue elastography in patients with and without rheumatoid arthritis (RA and non-RA groups, respectively).Methods: Altogether, 402 hands of 201 RA group and 222 hands of 111 non-RA group were included in the study. Ultrasonography was performed to evaluate the circumference, cross-sectional area (CSA) and strain ratio as an elasticity of the median nerve at the inlet level of the carpal tunnel and the proximal portion of the carpal tunnel inlet. Using propensity score matching, the difference between RA and non-RA group were analyzed.Results: After propensity score matching, 135 hands in 104 RA group and 70 non-RA group were finally analyzed. There were no significant differences in the circumference and CSA of the median nerve between the two groups. The strain ratio of the median nerve was significantly higher in RA group than in non-RA group only at the inlet of the carpal tunnel level.Conclusions: The nerve stiffness in patients with RA measured by ultrasound real-time tissue elastography was higher than without RA. Inflammatory condition of the flexor tendon and wrist joint in patients with RA may generate fibrotic changes in the median nerve.Trial registration: University Hospital Medical Information Network Clinical Trials Registry: UMIN000015314.

Principles of ultrasound elastography

Tissue stiffness has long been known to be a biomarker of tissue pathology. Ultrasound elastography measures tissue mechanical properties by monitoring the response of tissue to acoustic energy. Different elastographic techniques have been applied to many different tissues and diseases. Depending on the pathology, patient-based factors, and ultrasound operator-based factors, these techniques vary in accuracy and reliability. In this review, we discuss the physical principles of ultrasound elastography, discuss differences between different ultrasound elastographic techniques, and review the advantages and disadvantages of these techniques in clinical practice.

Optic Nerve Head Elastometry in Both Eyes of Patients with Unilateral Non-arteritic Anterior Ischaemic Optic Neuropathy - May It Be a Novel Aspect of the Pathogenesis?

In this prospective study, the biomechanical properties of optic nerve head (ONH) and cornea in both eyes of patients with non-arteritic anterior ischaemic optic neuropathy and healthy control eyes were investigated. ONH elastometry was measured with real-time elastography, and corneal elastometry was measured with ocular response analyser. Elastometry of cornea and ONH was lower in both eyes of patients with unilateral non-arteritic ischaemic optic neuropathy than in healthy control eyes. The role of these biomechanical differences in the pathogenesis of non-arteritic ischaemic optic neuropathy should be investigated further.

Evaluation of the diagnostic efficacy of strain elastography in infertile population with normal and abnormal semen parameters

OBJECTIVE

The aim of the present study was to investigate the diagnostic value of strain elastography (SE) of testicular tissues in infertile population. We also evaluated the correlation between SE results with semen parameters and hormone profiles of the patients.

MATERIAL AND METHODS

A total of 61 patients and 122 testes were evaluated. Patients who were evaluated in an andrology outpatient clinic with the diagnosis of infertility and referred to radiology department for investigation of reproductive organs between June 2015 and January 2016 were included. Patients were divided into two groups according to semen analyses results as normal (Group 1) and abnormal (Group 2). Hormone profiles, semen analyses, B-mode, coloured Doppler ultrasonography and sonoelastography examinations were performed for each patient. Measurements of testicular volumes, resistive indices (RI) in intraparenchymal arteries, strain, strain ratio (SR) and presence of varicocele were recorded.

RESULTS

Mean age of participants was 33.7±6.3 years. Mean testicular volumes (Group 1, 19.41±4.8 mL, and Group 2, 17.64±3.62 mL) were significantly different between groups (p=0.023). Mean SRs were also different between Groups 1 and 2 (0.12±0.08 vs. 0.22±0.18, p<0.001). Testicular volumes were directly proportional with SRs in Group 1. Strain values had inverse relationship with sperm concentration and total motile sperm counts in Group 2 (p=0.01). SRs were found to be positively correlated with RI and sperm morphology in Group 2 (p<0.05). Although FSH values showed significant difference among groups, any correlation between FSH and elastographic parameters could not be displayed.

CONCLUSION

Strain elastography results were found to be significantly different in patients with abnormal sperm counts. This technique may provide promising results, however, further large scale studies may help to clarify the value of this imaging modality in the assessment of male infertility.

Real-Time Ultrasound Elastographic Features of Primary Open Angle Glaucoma

OBJECTIVE

To investigate the significance of ultrasound elastography for evaluating the optic nerve in patients with primary open angle glaucoma (POAG).

METHODS

This prospective, comparative case series included 40 eyes of 40 patients. Twenty eyes with POAG comprised the POAG group, and 20 eyes of 20 patients without glaucoma who admitted to general eye clinic for near vision glasses comprised the control group. All real-time sonographicelastographic examinations were performed by the same physician. The ratio of orbital fat to optic nerve head (ROFON) and lateral rectus to optic nerve head (RLRON) were determined. Statistical analyses were performed using Student t test, Kolmogorov-Smirnov test, and χ test.

RESULTS

The mean ages of the patients in the study and the control groups were 65.10 ± 7.88 years (range, 48-80 years), and 69.15 ± 7.92 years (range, 55-89 years), respectively (P = 0.113). Mean ROFONs were 1.85 and 6.42 (P < 0.05), and mean RLRONs were 0.65 and 1.07 (P < 0.05) in the control and POAG groups, respectively.

CONCLUSIONS

Real-time elastography showed increased ROFON and RLRON in POAG patients. This can help to understand optic nerve head biomechanics and clarify glaucoma damage in early glaucoma cases.

Intrasurgical dignity assessment of hepatic tumors using semi-quantitative strain elastography and contrast-enhanced ultrasound for optimisation of liver tumor surgery

OBJECTIVE

To evaluate the efficacy of strain elastography (SE) using semi-quantitative measurement methods compared to constrast enhanced ultrasound during liver tumor surgery (Io-CEUS) for dignity assessment of focal liver lesions(FLL).

MATERIAL AND METHODS

Prospective data acquisition and retrospective analysis of US data of 100 patients (116 lesions) who underwent liver tumor surgery between 10/2010 and 03/2016. Retrospective reading of SE color patterns was performed establishing groups depending on dominant color (>50% blue = stiff, inhomogenous, >50% yellow/red/green = soft tissue). Semi-quantitative analysis was performed by Q-analysis based on a scale from 0 (soft) to 6 (stiff). 2 ROIs were placed centrally, 5 ROIs in the lesion's surrounding tissue. Io-CEUS was performed by bolus injection of 5-10 ml sulphurhexaflourid microbubbles evaluating wash-in- and -out- kinetics in arterial, portal venous and late phase. Histopathology after surgical resection served as goldstandard.

RESULTS

100 patients (m: 65, f: 35, mean age 60.5 years) with 116 liver lesions were included. Lesion's size ranged from 0.5 to 8.4 cm (mean 2.42 cm SD±1.44 cm). Postoperative histology showed 105 malignant and 11 benign lesions. Semi-quantitative analysis showed central indurations of >2.5 in 76/105 cases suggesting malignancy. 7 benign lesions displayed no central indurations correctly characterized benign by SE. ROC-analysis and Youden index showed a sensitivity of 72.4% and specificity of 63.6% assuming a cut-off of 2.5. Io-CEUS correctly characterized 103/105 as malignant. Sensitivity was 98%, specificity 72.7%.

CONCLUSION

Strain elastography is a valuable tool for non-invasive characterization of FLLs. Semi-quantitative intratumoral stiffness values of >2.5 suggested malignancy. However, sensitivity of Io-CEUS in detecting malignant lesions was higher compared to SE. In conclusion SE should be considered for routine use during intraoperative US in addition to Io-CEUS for optimization of curative liver surgery.

Quantitative US Elastography Can Be Used to Quantify Mechanical and Histologic Tendon Healing in a Rabbit Model of Achilles Tendon Transection

Purpose To determine the time-dependent change in strain ratios (SRs) at the healing site of an Achilles tendon rupture in a rabbit model of tendon transection and to assess the correlation between SRs and the mechanical and histologic properties of the healing tissue. Materials and Methods Experimental methods were approved by the institutional animal care and use committee. The Achilles tendons of 24 New Zealand white rabbits (48 limbs) were surgically transected. The SRs of Achilles tendons were calculated by using compression-based quantitative ultrasonographic elastography measurements obtained 2, 4, 8, and 12 weeks after transection. After in vivo elastography, the left Achilles tendon was harvested for mechanical testing of ultimate load, ultimate stress, elastic modulus, and linear stiffness, and the right tendons were harvested for tissue histologic analysis with the Bonar scale. Time-dependent changes in SRs, mechanical parameters, and Bonar scale scores were evaluated by using repeated-measures analysis of variance. The correlation between SRs and each measured variable was evaluated by using the Spearman rank correlation coefficient. Results Mean SRs and Bonar scale values decreased as a function of time after transection, whereas mechanical parameters increased (P < .001). SR correlated with ultimate stress (ρ = 0.68, P <.001,) elastic modulus (ρ = 0.74, P <.001), and the Bonar scale (ρ = 0.87, P <.001). Conclusion Quantitative elastography could be a useful method with which to evaluate mechanical and histologic properties of the healing tendon. ^© RSNA, 2017 Online supplemental material is available for this article.

Maximum Value Measured by 2-D Shear Wave Elastography Helps in Differentiating Malignancy from Benign Focal Liver Lesions

The goal of the work described here was to evaluate the diagnostic efficacy of 2-D shear wave elastography (2-D SWE) in differentiating malignancy from benign focal liver lesions (FLLs). The maxima, minima, means and the standard deviations of 2-D SWE measurements, expressed in kilopascals (Emax, Emin, Emean, ESD), were obtained for 221 patients with 229 FLLs. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of 2-D SWE. The Mann-Whitney U-test was used to assess inter-group differences. Emax, Emin, Emean and ESD were significantly higher in the 164 malignant lesions than in the 65 benign lesions (p < 0.001). For identification of malignant FLLs, the areas under receiver operating characteristic curves for Emax, Emin, Emean and ESD were 0.920, 0.710, 0.879 and 0.915, respectively. Emax was 96.21 ± 35.40 for 19 intrahepatic cholangiocarcinomas and 90.32 ± 54.71 for 35 liver metastatic lesions, which were significantly higher than 61.83 ± 28.87 for 103 hepatocellular carcinomas (p < 0.0001 and p = 0.0237). Emax was 38.72 ± 18.65 for 15 focal nodular hyperplasias, which was significantly higher than 20.56 ± 10.74 for 37 hemangiomas (p = 0.0009). The Emax values for adjacent liver parenchyma of hepatocellular carcinomas and intrahepatic cholangiocarcinomas were significantly higher than those for the other three lesion types (p < 0.005). In conclusion, Emax values of FLLs and adjacent liver parenchyma could help in differentiating malignant from benign FLLs.

Interpretation of thyroid glands in a group of healthy children: real-time ultrasonography elastography study

BACKGROUND

This study aimed to determine the strain index (SI) of normal thyroid parenchyma in a group of healthy children, using ultrasound elastography (USE).

METHODS

The participants consisted of 54 healthy children. The USE of the normal thyroid parenchyma was performed by using the Hitachi Hi VisionPreirus model ultrasonography (US) device. By following sinusoidal waves at the base of the screen, regular and slight compressions and decompressions were made by the transducer. After the regular sinusoidal waves were acquired, standard region of interest (ROI) circles were used to measure the SI values of the thyroid glands by placing one ROI on a superficial part of the normal thyroid gland parenchyma and the other on the adjacent soft tissue at the same depth (within 10-mm proximity). Three measurements were obtained for each (right and left) thyroid gland, and the mean value was used for statistics.

RESULTS

The mean SI value of normal thyroid glands was 0.54±0.38 for the whole group. There was no statistically significant difference between girls and boys on the basis of age, weight, height, BMI (body mass index), and thyroid SI values (p=0.15, p=0.18, p=0.12, p=0.31, and p=0.96, respectively). No correlation was found between thyroid gland SI values and each of the following variables: age (r=0.22, p=0.15), gender (r=0.007, p=0.96), and BMI (r=0.26, p=0.09).

CONCLUSIONS

The study determined the normal elasticity values of thyroid glands in healthy children. Such information can serve as a baseline from which thyroid diseases can be examined.

The Avaibility of Strain Elastography in a Hydatid Cyst - Interobserver Study

Background

To differentiate the hydatid cyst (HC) types by ultrasound elastography using two different sizes (4 mm and 8 mm) of the region of interest (ROI) and asking two different radiologists (interobserver) for their opinion.

Material/Methods

Patients with HC were evaluated by USG elastography. The statistical anayses were performed using Strain index (SI) which is the unit of strain elastography.

Results

A total of 26 out of 33 patients were female, and 7 were male. The mean age was 38.85±17.62 (range from 10 to 72 years). Type I: 6, Type 2: 6, Type III: 6, Type IV: 11, Type V: 4. There was no significant difference in HC SI (regardless of types) between O1 and O2, and 4-mm and 8-mm ROI (p>0.05). There was no statistically significant difference between SI of HC types of interobservers (O1–O2) and ROI sizes (4–8 mm) (p>0.05 for all parameters). The highest correlation between HC types and ROI sizes was in ROI size of 4 mm.

Conclusions

The correlation between SI and types was reliable in standard-applied 4-mm ROI. There was no statistically significant difference between interobservers in SI values. Thus, elastography tecnhnique is objective for HC but not appropriate to differentiate the types.

Diagnostic value of strain elastography for differentiation between renal cell carcinoma and transitional cell carcinoma of kidney

PURPOSE

The objective of our study was to prospectively evaluate the diagnostic performance of strain elastography for differentiation between renal cell carcinomas (RCCs) and transitional cell carcinomas (TCCs) of kidney.

METHODS

A total of 99 consecutive patients who were referred to our hospital because of a newly diagnosed solid renal mass suspicious for malignancy on radiological screenings were evaluated with sonography, including strain elastography. Strain elastography was used to compare the stiffness of the renal masses and renal cortex. The ratio of strain in a renal mass and nearby renal cortex was defined as the strain index value. Mean strain index values for RCCs and TCCs were compared, and mean strain index values between histological subtypes of RCC were also compared.

RESULTS

Although TCCs were smaller than RCCs (p < 0.001), there were no significant differences in gender distribution and mean age of the patients, and mean probe-tumor distance between RCC and TCC. The mean strain index value ±SD for TCC (5.18 ± 1.12) was significantly higher than the value for RCC (4.04 ± 0.72; p < 0.001). Mean strain index value for papillary cell carcinomas (4.09 ± 0.45) was slightly higher than that for clear cell carcinomas (3.85 ± 0.78): however, the difference was not statistically significant (p = 0.51).

CONCLUSIONS

Strain elastography can be used as a valuable imaging technique for preoperative differentiation between RCC and TCC of kidney.

Percutaneous real-time sonoelastography as a non-invasive tool for the characterization of solid focal liver lesions: A prospective study

BACKGROUND

Real-time sonoelastography is currently used for the characterization of superficial solid lesions such as thyroid and breast masses. This study evaluates the usefulness of percutaneous sonoelastography for the characterization of solid focal liver lesions.

METHODS

30 out of 43 patients with 38 known liver lesions were included in a prospective, diagnostic study. Qualitative analysis (pattern of deformation, elasticity type of liver tumour) and semi-quantitative measurements (strain ratio, hardness percentage, histogram) were evaluated. Sensitivity, specificity, positive and negative predictive values were calculated and the area under the receiver operating characteristics curve was constructed.

RESULTS

Patterns A and C-D are specific of benign lesions and metastases respectively. The patterns for haemangiomas, focal nodular hyperplasia and metastases were significantly different to each other in terms of strain ratio, hardness percentage and histogram (p<0.05). A statistically significant difference (p<0.001) was observed between the median values of the 3 measured parameters for benign (1.02; 12%; 47) and malignant lesions (1.66; 65%; 20.5) respectively. The area under the receiver operating characteristics curve values for strain ratio, hardness percentage and histogram were 0.88, 0.89, and 0.86 respectively for cut-off values of 1.2, 45, and 30.

CONCLUSIONS

By percutaneous sonoelastography it is possible to differentiate benign versus malignant focal liver lesions, metastases in particular, with good diagnostic performance.

Quantitative Ultrasound Elastography With an Acoustic Coupler for Achilles Tendon Elasticity: Measurement Repeatability and Normative Values

OBJECTIVES

The purposes of this study were to measure intraobserver and interobserver repeatability of quantitative elastography using an acoustic coupler for the Achilles tendon, to compare elastographic values among different age groups, and to assess the correlation between quantitative and conventional qualitative measurements.

METHODS

One hundred asymptomatic Achilles tendons of 50 volunteers were examined. For quantitative elastography, the strain value of the tendon was divided by that of the acoustic coupler with a known Young modulus, and the strain ratio was calculated. B-mode image assessment and qualitative elastography were also performed. Intraobserver repeatability and interobserver repeatability of strain ratio measurements were calculated. The strain ratios were compared among age groups by the Kruskal-Wallis test. Additionally, strain ratios for each B-mode grade and qualitative elastographic grade were compared by the Wilcoxon signed rank test.

RESULTS

Intraobserver repeatability intraclass correlation coefficient (1, 3) values were 0.87 and 0.93, respectively. The correlation coefficient between the observers' measurements was 0.61. The strain ratio for the 30s age group was 0.27, which was significantly lower than the values for the other age groups (P < .001). Although 97 of 100 tendons were normal on B-mode evaluations, 36 of the 97 tendons were degenerated on qualitative elastography and also had higher strain ratio values than normal tendons.

CONCLUSIONS

Quantitative elastography using an acoustic coupler is a reproducible technique for measuring the elasticity of the Achilles tendon. It may detect early tendon degeneration that is not depicted on B-mode imaging.

Elastography: history, principles, and technique comparison

Elastography is a relatively new imaging technology that creates images of tissue stiffness. It can be thought of an extension of the ancient technique of palpation but it gives better spatial localization information and is less subjective. Two main types of elastography are currently in use, strain elastography where the tissue displacement in response to gentle pressure is used to compute and image tissue strain, and shear wave elastography where the speed of shear waves traversing tissue is measured and used to create an image of tissue stiffness. Each method has advantages and disadvantages but generally strain imaging is excellent for focal lesions and shear wave imaging, being more quantitative, is best for diffuse organ diseases. Strain imaging requires additional training in acquisition technique to obtain high quality images. Pitfalls to avoid and tips for good images are provided. Improvements in strain imaging are focused on better quality indicators and better methods for quantification. Improvements in shear wave imaging will be higher frame rates, greater accuracy in focal lesions, and making results more comparable between different ultrasound systems. Both methods will continue to improve and will provide ever more powerful new tools for diagnosis of diffuse and focal diseases.

Elasticity of the tibial nerve assessed by sonoelastography was reduced before the development of neuropathy and further deterioration associated with the severity of neuropathy in patients with type 2 diabetes

Aims/Introduction

To measure the elasticity of the tibial nerve using sonoelastography, and to associate it with diabetic neuropathy severity, the cross‐sectional area of the tibial nerve and neurophysiological findings in type 2 diabetic patients.

Materials and Methods

The elasticity of the tibial nerve was measured as the tibial nerve:acoustic coupler strain ratio using high‐resolution ultrasonography in 198 type 2 diabetic patients stratified into subgroups by neuropathy severity, and 29 control participants whose age and sex did not differ from the diabetic subgroups.

Results

The elasticity of the tibial nerve in patients without neuropathy (P < 0.001) was reduced compared with controls (0.76 ± 0.023), further decreasing (0.655 ± 0.014 to 0.414 ± 0.018) after developing neuropathy. The cut‐off value of elasticity of the tibial nerve that suggested the presence of neuropathy was 0.558. The area under the curve (0.829) was greater than that for the cross‐sectional area (0.612). The cross‐sectional area of the tibial nerve in diabetic patients without neuropathy (6.11 ± 0.13 mm²) was larger than that in controls (4.84 ± 0.16 mm²), and increased relative to neuropathy severity (P < 0.0001). The elasticity of the tibial nerve was negatively associated with neuropathy severity (P < 0.0001), cross‐sectional area (P = 0.002) and 2000 Hz current perception threshold (P = 0.011), and positively associated with nerve conduction velocities (P < 0.0001).

Conclusions

Determining the elasticity of the tibial nerve in type 2 diabetic patients could reveal early biomechanical changes that were likely caused by thickened fibrous sheaths of peripheral nerves, and might be a novel tool for characterizing diabetic neuropathy.

A comparative study of strain and shear-wave elastography in an elasticity phantom

OBJECTIVE. The purpose of this study was to assess the diagnostic accuracy of strain and shear-wave elastography for determining targets of varying stiffness in a phantom. The effect of target diameter on elastographic assessments and the effect of depth on shear-wave velocity were also investigated. MATERIALS AND METHODS. We examined 20 targets of varying diameters (2.5-16.7 mm) and stiffnesses (8, 14, 45, and 80 kPa) with a 4-9-MHz linear-array transducer. Targets were evaluated 10 times with three different methods-shear-wave elastography, strain ratio, and strain histogram analysis-yielding 600 evaluations. AUCs were calculated for data divided between different stiffnesses. A 1.5-6-MHz curved-array transducer was used to assess the effect of depth (3.5 vs 6 cm) on shear-wave elastography in 80 scans. Mixed model analysis was performed to assess the effect of target diameter and depth. RESULTS. Strain ratio and strain histogram AUCs were higher than the shear-wave velocity AUC (p < 0.001) in data divided as 80 versus 45, 14, and 8 kPa. In data divided as 80 and 45 versus 14 and 8 kPa, the methods were equal (p = 0.959 and p = 1.000, respectively). Strain ratios were superior (p = 0.030), whereas strain histograms were not significantly better (p = 0.083) than shear-wave elastography in data divided as 80, 45, and 14 versus 8 kPa. Target diameter had an effect on all three methods (p = 0.001). Depth had an effect on shear-wave velocity (p = 0.001). CONCLUSION. The ability to discern different target stiffnesses varies between shear-wave and strain elastography. Target diameter affected all methods. Shear-wave elastography is affected by target depth.

Utility of semiquantitative strain elastography for differentiation between benign and malignant solid renal masses

OBJECTIVES

The aim of this study was to determine the role of semiquantitative strain elastography for differentiation of benign and malignant solid renal masses.

METHODS

Seventy-one patients with solid renal masses were prospectively examined with ultrasound elastography after grayscale sonography. Strain elastography was used to compare the stiffness of the renal masses and renal parenchyma. The ratio of strain in a renal mass and nearby renal parenchyma was defined as the strain index value. Mean strain index values for benign masses (n = 29; 24 angiomyolipomas and 5 oncocytomas) and malignant masses (n = 42; 34 renal cell carcinomas, 4 transitional cell carcinomas, 3 metastases, and 1 lymphoma) and mean strain index values for angiomyolipomas and renal cell carcinomas were compared.

RESULTS

There were no significant differences in the mean age of the patients, mean diameter of the masses, and mean probe-mass distance between benign and malignant groups. The mean strain index value ± SD for malignant masses (4.05 ± 2.17) was significantly higher than the value for benign masses (1.43 ± 0.94; P < .05). The mean strain index value for renal cell carcinomas (4.30 ± 2.27) was significantly higher than the value for angiomyolipomas (1.28 ± 1.01; P < .0001).

CONCLUSIONS

Strain elastography may be a useful imaging technique for differentiation between benign and malignant solid renal masses.

Strain elastography in the characterization of renal cell carcinoma and angiomyolipoma

INTRODUCTION

We evaluate the diagnostic performance of strain elastography to differentiate renal cell carcinoma (RCC) from angiomyolipoma (AML).

METHODS

Strain elastography was performed in 65 patients (mean age 55.5 years; range: 32-81) who had renal lesions (24 AMLs and 41 RCCs) prospectively. Lesions were classified according to lesion size and histological subtypes. The strain ratios of the RCCs and AMLs were evaluated by a radiologist. The area under the curve and the cut-off point were used to assess diagnostic performance. Sensitivity, specificity, and positive and negative predictive values were obtained.

RESULTS

In assessing the mean strain ratio, we divided the groups in 3 according to size: (1) <20-mm lesions; (2) 20- to 40-mm lesions; and (3) >40-mm lesions; the respective mean strain ratios were: 1.5 ± 0.5 (range: 0.06-5.92), 2.8 ± 0.4 (range: 0.17-9.92), 2.7 ± 0.3 (range: 0.08-6.15). When RCCs and AMLs were compared, there was a statistically significant difference in the strain ratio among the 3 groups divided per lesion size (p < 0.01). For the strain ratio, the mean ± standard deviation was 1.1 ± 0.1 for AMLs and 3.4 ± 0.3 for RCCs (p < 0.01). When lesion subtypes were compared, there was a statistically significant difference in the strain ratio between the AML and clear cell RCC (p < 0.01).

CONCLUSIONS

For assessing renal lesions, strain elastography and strain ratio values may be useful in differentiating RCCs from AMLs.

Endorectal ultrasonography, strain elastography and MRI differentiation of rectal adenomas and adenocarcinomas

AIM

Strain elastography is a method for recording tissue hardness. Strain in different areas may be compared using strain ratio (SR). The aims of this study were to validate a previously proposed SR cut-off value of 1.25 for differentiating adenocarcinomas from adenomas and to compare the performance of endorectal ultrasonography (ERUS), strain elastography and MRI in the same patients.

METHOD

A prospective evaluation of 120 consecutive patients with rectal neoplasia, using a predetermined elastography strain ratio cut-off value, was performed to differentiate adenomas from adenocarcinomas. ERUS and MRI were performed according to standard routine at Haukeland University Hospital, defining T0 as adenomas and T1-T4 as adenocarcinomas. Subsequent histopathology was used as the reference standard.

RESULTS

Histopathological evaluation revealed 21 adenomas and 99 adenocarcinomas. Sensitivity, specificity and accuracy (with 95% CI) were as follows: ERUS: 0.96 (0.90-0.99), 0.62 (0.40-0.80) and 0.90 (0.83-0.94); elastography SR: 0.96 (0.90-0.99), 0.86 (0.66-0.96) and 0.94 (0.88-0.97); and MRI: 0.99 (0.94-1.00), 0.07 (0.00-0.31) and 0.87 (0.80-0.93).

CONCLUSION

This study confirms that the elastography SR assessment accurately differentiates sessile adenomas from adenocarcinomas. SR assessment has a superior ability to differentiate adenomas and adenocarcinomas when compared with ERUS and MRI. MRI examination seems unable to recognize adenomas and should be interpreted with care when early-stage rectal neoplasia is suspected.

Combined endorectal ultrasonography and strain elastography for the staging of early rectal cancer

AIM

Strain elastography is a novel approach to rectal tumour evaluation. The primary aim of this study was to correlate elastography to pT stages of rectal tumours and to assess the ability of the method to differentiate rectal adenomas (pT0) from early rectal cancer (pT1-2). Secondary aims were to compare elastography with endorectal ultrasonography (ERUS) and to propose a combined strain elastography and ERUS staging algorithm.

METHOD

In all, 120 consecutive patients with a suspected rectal tumour were examined in this staging study. Patients receiving surgery without neoadjuvant radiotherapy were included (n = 59). All patients were examined with ERUS and elastography. Treatment decisions were made by multidisciplinary team (MDT) assessment, without considering the strain elastography examination.

RESULTS

Histopathology identified 21 adenomas, 13 pT1, 9 pT2, 15 pT3 and one pT4. Mean elastography strain ratios were predictive of T stage (P = 0.01). Differentiation of adenomas from early rectal cancer (pT1-2) had sensitivity, specificity and accuracy of 0.82, 0.86 and 0.84 for elastography and 0.82, 0.62 and 0.72 for ERUS. A combined staging algorithm was developed to identify tumours eligible for local resection. Based on MDT evaluation 32% of tumours later identified as pT0 or pT1 were treated with total mesorectal excision, even though a local excision might have sufficed. Combined ERUS and elastography evaluation would have significantly reduced this number to 9% (P = 0.008).

CONCLUSION

Elastography may improve the staging of adenomas and early rectal cancer compared with ERUS alone. Combined ERUS and elastography assessment is likely to further improve the selection of patients for local resection.

The value of real-time ultrasound elastography in chronic autoimmune thyroiditis

OBJECTIVE

Chronic autoimmune thyroiditis (CAT) (chronic lymphocytic thyroiditis-Hashimoto's thyroiditis), which is the most common inflammatory disorder of the thyroid gland, causes hypothyroidism. Ultrasound elastography is a newly developed sonographic technique that provides an estimation of tissue elasticity by measuring the degree of tissue displacement under the application of an external force. In this study, our aim was to evaluate the accuracy of strain index ratio with real-time ultrasound elastography and to calculate the cut-off point for the diagnosis of CAT. Our aim was also to lead further studies on other pathological changes such as lymphoma, malign nodules etc. based on CAT by using this cut-off point. The gains from this study and further studies will assist clinical diagnoses and follow-up.

METHODS

Aplio™ 500 ultrasound machine (Toshiba Medical Systems Co. Ltd, Otawara, Japan) with linear 4.8-11.0 MHz transducers and elastography software was used. Routine B-mode (dimensions and parenchymal echogenicity) ultrasound evaluation was performed prior to the ultrasound elastography.

RESULTS

A total of 31 randomized patients (3 males, 28 females) with a mean age of 39.13 ± 10.16 years (range, 16-58 years) with CAT and 21 healthy controls (6 males, 15 females) with mean age of 34.67 ± 16.31 years (range, 14-81 years) were prospectively examined. The mean values of thyroid-stimulating hormone (TSH; normal TSH value is 0.27-4.20 IU ml(-1)) and anti-thyroid peroxidase (anti-TPO; normal anti-TPO value is 0-34 IU ml(-1)) were 3.40 ± 2.70 and 373.66 ± 148.94 IU ml(-1), respectively. No correlation was detected between serum TSH and thyroid tissue strain index (Spearman r coefficient of TSH was -0.290). Positive-sided correlation was detected between anti-TPO values and thyroid tissue strain index ratio (Spearman r coefficient of anti-TPO was 0.682). The median strain index ratio of patients with CAT (1.39 ± 0.72) was significantly higher than the mean ratio of the controls (0.76 ± 0.55). The area under the receiver operating characteristic curve was 0.775 (95% confidence interval). The optimal cut-off value (in which the sum of sensitivity and specificity was highest) for the prediction of diffuse thyroid pathology was 0.677. For this cut-off ratio, thyroid stiffness had 96% sensitivity and 67% specificity. A total of 30 of 31 patients (96%) and a total of 7 of 21 healthy controls (33%) exceeded the cut-off points.

CONCLUSION

The strain index ratio was higher in CAT than in normal thyroid parenchyma in real-time ultrasound elastography. Thus, it seems to be a useful method for the assessment of CAT with real-time ultrasound elastography, and further studies assessing the correlation of sonoelastography findings and histopathological subtypes of CAT would enrich the findings of the present study.

ADVANCES IN KNOWLEDGE

In our study, we detected the stiffness ratio of the thyroid tissue in patients with CAT. The cut-off value should be helpful for diagnosis or follow-up of the recently developed lesions such as lymphoma, malign nodule, etc. based on CAT. This study should also encourage new studies about CAT and ultrasound elastography.

Carpal tunnel syndrome: diagnosis by means of median nerve elasticity--improved diagnostic accuracy of US with sonoelastography

PURPOSE

To compare the elasticity of the median nerve (MN) between healthy volunteers and patients with carpal tunnel syndrome (CTS) and to evaluate the diagnostic utility of sonoelastographic measurements of the elasticity of the MN.

MATERIALS AND METHODS

This study was performed with institutional review board approval and written informed consent from all participants. Hands in 22 healthy volunteers and in 31 patients with symptomatic CTS were studied. The cross-sectional area (CSA) and the elasticity of the MN, which was measured as the acoustic coupler (AC)/MN strain ratio, were evaluated.

RESULTS

Both hands in 22 healthy volunteers (three men [mean age, 52.7 years; age range, 41-65 years]; 19 women [mean age, 62.2 years; age range, 40-88 years]) and 43 hands in 31 patients with symptomatic CTS (three men [mean age, 69.0 years; age range, 46-88 years]; 28 women [mean age, 61.2 years; age range, 39-92 years]) were studied. Both the AC/MN strain ratio and the CSA in the patients with CTS were significantly higher than those in the healthy volunteers (P < .001). The presence of CTS was predicted by means of AC/MN strain ratio and CSA cutoff values, respectively, of 4.3 and 11 mm(2), with areas under the receiver operating characteristic curves (AUCs) of 0.78 (95% confidence interval [CI]: 0.69, 0.88) and 0.85 (95% CI: 0.78, 0.93). A logistic model that combined the AC/MN strain ratio and the CSA improved diagnostic accuracy for CTS, with an AUC of 0.91 (95% CI: 0.85, 0.97; P < .001).

CONCLUSION

Sonoelastography provides significant improvement in the diagnostic accuracy of the ultrasonographic assessment of CTS.

Ultrasound elastography: advantages, limitations and artefacts of the different techniques from a study on a phantom

Ultrasound elastography is a technique currently under development. Its use in clinical practice is complicated because of the wide range of techniques used by the different manufacturers and the parameters proposed to characterise tissues. A comparative analysis on five ultrasound diagnostic systems has been performed on a calibrated elasticity phantom and demonstrated that: (1) all systems tested are reliable for simple qualitative analysis: is a nodule present and is it harder or softer than neighbouring tissues? (2) the deformation or hardness ratios between two regions are usually, however, not proportional to the theoretical ratios and only a binary analysis greater than 1 (harder) and less than 1 (softer) is reliable and could be used as a negative predictive value (NPV) for malignant lesions, as has been suggested by some authors; (3) finally, quantitative analysis using shear wave techniques performed variably, reliable measurements being obtained with only one of the systems. Measurements produced by these different systems must not be compared in clinical practice to monitor a patient and the threshold values proposed in the literature must only be used in an analysis carried out with the same system and same probe.

Interobserver variability of ultrasound elastography in transplant kidneys: correlations with clinical-Doppler parameters

Real-time sonoelastography (RSE) is a relatively new imaging technique that visualizes relative difference in tissue hardness by evaluating changes in local strain in response to external stress. Our aim was to evaluate the ability of investigators to use sonoelastography to detect differences in renal cortical stiffness and assess the relationship between stiffness and clinical-Doppler parameters. In 42 adult renal transplant recipients, sonoelastography of kidney was performed to calculate the strain ratio (SR) of the central echo complex to the renal parenchyma. Resistive index (RI) and pulsatility index (PI) were also measured. Estimated glomerular filtration rate (eGFR) was calculated. Parenchymal stiffness showed significant positive correlation with RI and PI (r: 0.41 p = 0.007 and r: 0.48 p = 0.001, respectively). Parenchymal stiffness and eGFR did not have a significant correlation (p = 0.42). Interobserver agreement, expressed as intraclass correlation coeffiicient was 0.47 (95% CI: 0.05-0.70). Parenchymal stiffness (SR) showed significant positive correlation with RI and PI but sonoelastography has also wide range intra- and low interobserver agreement in renal transplants. Further studies are warranted in larger patient groups to determine the reliability of sonoelastography in renal transplants.