Strain Ratio Method Research Articles

The value of ultrasonic elastography in the differential diagnosis of choroidal melanoma and choroidal hemangioma

Objective: To explore the role of the scoring and strain ratio methods of ultrasonic elastography in the differential diagnosis of choroidal melanoma and choroidal hemangioma. Methods: A cross-sectional study. Twenty-five patients (25 eyes) with choroidal melanoma treated in the Department of Ophthalmology, Beijing Tongren Hospital, Capital Medical University from July to October 2016 were included in this study. There were 13 males and 12 females, with an average age of (48±12) years old. Twenty-five patients (25 eyes) with choroidal hemangioma treated in the same period were selected for differential diagnosis, including 12 males and 13 females, with an average age of (37±13) years. The lesions were examined by ultrasound elastography and scored, and the strain ratio of the tumor to the orbital tissue was measured. Two independent sample t test was used to compare the difference in the elasticity score and strain ratio between choroidal melanoma and choroidal hemangioma. The sensitivity, specificity and area under the receiver operating characteristic (ROC) curve were calculated to analyze the value of the two methods in the differential diagnosis of choroidal melanoma and choroidal hemangioma. Results: The elastography score of choroidal melanoma was (3.48±0.77) points, including 2 points in 3 cases, 3 points in 8 cases, 4 points in 13 cases, and 5 points in 1 case. The elastography score of hemangioma was (2.28±0.46) points, including 2 points in 18 cases and 3 points in 7 cases. The difference in the elasticity score between patients with the two kinds of tumors was statistically significant (t=6.694, P<0.01). The strain ratio was 42.97±15.83 and 12.21±9.24 in the patients with choroidal melanoma and choroidal hemangioma, respectively, and the difference was statistically significant (t=8.392, P<0.01). Using 3 points as the diagnostic critical point of the elastography score, the sensitivity was 88.0%, the specificity was 72.0%, and the area under the ROC curve was 0.80 (95% cofidence interval: 0.663 to 0.900, P<0.01). Using 21.67 as the diagnostic critical point of the strain ratio, the sensitivity was 92.0%, the specificity was 92.0%, and the area under the ROC curve was 0.92 (95% cofidence interval: 0.808 to 0.978, P<0.01). Conclusions: Ultrasound elastography plays a role in the differential diagnosis of choroidal melanoma and choroidal hemangioma. The differential diagnostic value of the strain ratio method is higher than the scoring method. (Chin J Ophthalmol, 2020, 56: 676-680).

Diagnostic Performance and Accuracy of the 3 Interpreting Methods of Breast Strain Elastography: A Systematic Review and Meta-analysis.

There are 3 methods of interpreting breast strain elastography: the elastographic-to-B-mode length ratio (E/B), a 5-point color scale (5P), and the strain ratio (SR). This meta-analysis assessed which method is superior to the others. A systematic search of the medical literature was performed in July 2017. Studies were eligible for inclusion if they fulfilled the following criteria: (1) had biopsy-proven or long-term stability as the reference standard; (2) used either the E/B, 5P, or SR to interpret results; and (3) had at least 50 cases. A total of 220 records were retrieved; 60 full-text articles were examined, and 46 were included in the meta-analysis. Publication years ranged from 2007 and 2017. The quality of studies was generally high. The mean age of women was 48 years; 12,398 lesions (4242 malignant) were analyzed. For the 5P method, the sensitivity was 77%; specificity, 87%; positive likelihood ratio (LR), 5.3; and negative LR, 0.24. For the SR method, sensitivity was 87%; specificity, 81%; positive LR, 4.8; and negative LR, 0.16. For the E/B method, sensitivity was 96%; specificity, 88%; positive LR, 7.1; and negative LR, 0.03. Of the 3 methods, the E/B had the highest sensitivity, and the E/B and 5P had the highest specificity. With a negative LR of 0.03, the E/B method can downgrade lesions with a pretest probability of 50% to a 2% probability of malignancy.

An Innovative Ultrasound Strain Elastographic Method for the Differential Diagnosis of Breast Tumors

In this monocentric perspective study examining 64 lesions (19 benign and 45 malignant), we tested an innovative ultrasound elastographic method for diagnosing breast tumors. A new region of control and a new index designating the strain ratio (SR) were used. A traditional ultrasound elastographic method was used as the control. The results indicated that the SR ratios of the benign and malignant groups were 0.25 ± 0.22 and 1.10 ± 1.53, respectively, and this difference was statistically significant. The area under the receiver operating characteristic curve of the SR ratio method was 0.95, the cutoff point was 0.37 and the sensitivity and specificity were 95.56% and 94.74%, respectively. The two receiver operating characteristic curves of the traditional method and the SR of the proposed method were significantly different, at a p value of 0.02. Compared with that of the traditional method, the SR obtained with the new method had a larger area under the receiver operating characteristic curve, sensitivity, specificity and objectivity.

Strain Elastography: A Valuable Additional Method to BI-RADS?

Breast lesions classified as BI-RADS-US 3 are probably benign and observation was recommended, while a considerable number of BI-RADS-US 4 lesions were benign, resulting in excessive biopsies. We focus exclusively on BI-RADS-US 3 and 4 lesions and hypothesize that improved diagnostic performance can be achieved by integrating real-time elastography (strain ratio) into the BI-RADS-US classification system. From April 2010 to September 2015, 1071 lesions were included in the final analysis. After the conventional ultrasound examination, the BI-RADS-US (2013) classification was used to evaluate the lesions. Then the strain ratios were calculated, and the final diagnosis was made on the basis of histological results. The sensitivity, specificity, accuracy, PPV and NPV were calculated and the AUCs were compared. Additionally, an analysis of the diagnostic performance expressed by the pretest and posttest probability of disease (POD) was performed in BI-RADS-US 3 and 4A lesions. With the cutoff point of 2.98, the sensitivity, specificity and accuracy of the strain ratio method were 86.9 %, 86.6 % and 82.6 %, respectively. In BI-RADS-US 3 lesions, a suspicious strain ratio significantly modified the POD from 1.3 % to a posttest POD of 29.8 %. In BI-RADS-US 4A lesions, a suspicious strain ratio significantly modified the POD from 8.5 % to a posttest POD of 48.7 %. Ultrasonographic elastography (strain ratio) yields additional diagnostic information in the evaluation of BI-RADS-US 3 and 4 breast lesions. The strain ratios should be integrated into the BI-RADS-US classification system and into daily practice.

Role of Ultrasound Elastography in Characterization of Indeterminate Breast lesions (BIRADS 3&amp;4 lesions).

With the expanded role of screening breast ultrasonography and accumulating clinical experience, the American College of Radiology (ACR) has established the Breast Imaging Reporting and Data System (BI-RADS) ultrasonography lexicon to standardize terminology for description and management recommendations according to stratified risks. It has been established that probably benign (BI-RADS category 3) lesions having a malignancy rate of less than 2% require short-term imaging follow-up rather than immediate biopsy. The BI-RADS 4 category is assigned to suspicious lesions for which biopsy is recommended. Routine screening methods such as mammography and breast ultrasound are valuable methods for managing breast masses. Breast ultrasound is the preferable screening method as it provides high sensitivity for detecting breast cancer in women with dense breast tissue and can detect cancers not identified on mammography in asymptomatic women with dense breast tissue. In our study we included 46 patients with different breast lesions. All patients had a conventional B-mode ultrasound examination and were evaluated according to the BIRADS categories, then real time free-hand ultrasound elastography was performed in the same session and images were evaluated using both the Tsukuba elasticity score and the strain ratio method. Finally, the results were compared to the histopathologic results of those lesions. It was found that conventional B-mode ultrasound examination had a sensitivity of 72.73% and specificity of 83% While, elastography scoring alone turned out to have sensitivity of 65.5%, specificity of 83.4% using the Tsukuba score system. The additional of Strain ratio parameter for evaluating the elastography images showed the highest sensitivity 98.4% and specificity 85.68% at a best cutoff point of 3.47. So we have found that elastography is an easy procedure with high diagnostic performance which can be easily integrated with the B-mode ultrasound examination in the same session and improves its specificity. That has proven benefit in minimizing the number of unnecessary biopsies especially in the assessment of BIRADS 3 and 4 lesions

A multicenter study to confirm further diagnostic value of strain ratio method giving to 5-point scoring by elastography for differentiation of breast lesions

Objective To confirm whether strain ratio should be added after evaluation of lesions with 5-point elasticity scoring for differentiating breast lesions on ultrasonic elastography (UE). Methods Eight hundred and forty-six consecutive female patients with 1 071 breast lesions were recruited into a multicenter retrospective study, which involved 8 centers across China. All the patients underwent the UE procedure and the strain ratios were calculated. The sensitivity, specificity, accuracy, PPV and NPV were calculated for each of the two evaluation systems and the areas under the ROC curve were compared. Results The strain ratios of 559 benign lesions (2.7±1.4) and 512 malignant lesions (8.1±5.9) were significantly different (P<0.001). When the cutoff point was 3.03, strain ratio method had 81.6% sensitivity, 89.7% specificity, 81.7% accuracy, 80.2% PPV and 84.2% NPV. The areas under the ROC curve with the strain ratio method and 5-point scoring method were 0.865 and 0.862, respectively (P=0.622). For the lesions with elasticity score 3 and 4, the areas under the ROC curve of the two methods were 0.711 and 0.629, respectively(P=0.020). Conclusions Although the two UE methods have similar diagnostic performance, separate calculation of the strain ratios seems compulsory, especially for the lesions with elasticity score 3 and 4. Key words: Elasticity imaging techniques; Breast diseases; Strain ratio; Elasticity score

Forming and fracture limits of sheet metals deforming without a local neck

Under certain strain paths (e.g., balanced biaxial) and during some forming processes (e.g., incremental forming, micro forming), sheet metals may deform and fail without forming a local neck. In these cases, it is challenging to determine the forming limits using standard tests and measurement methods (ISO) designed to detect the formability from a sharp, single local neck. In this work, local necking was suppressed in an Al-6061-T6 alloy and a DC-04 steel with an in-plane biaxial (cruciform) test, and the fracture limits of these materials were measured at various strain paths together with the forming limits by an alternative Marciniak-Kuczynski based thickness strain ratio method (TRM). The measured strains were compared with the standard Nakajima tests containing sharp local necks. Due to the unique geometry of the cruciform test, both materials developed strain localizations and deformed until fracture without deviating from the predetermined strain ratio. This enabled a true measure of fracture strains of both materials, which was not possible with the standard tests. Moreover, the ISO method was not applicable to the case without local necking, whereas TRM resulted in similar forming limits in both tests.

Real time endoscopic ultrasound elastography and strain ratio in the diagnosis of solid pancreatic lesions.

AIMTo evaluate the accuracy of the elastography score combined to the strain ratio in the diagnosis of solid pancreatic lesions (SPL).METHODSA total of 172 patients with SPL identified by endoscopic ultrasound were enrolled in the study to evaluate the efficacy of elastography and strain ratio in differentiating malignant from benign lesions. The semi quantitative score of elastography was represented by the strain ratio method. Two areas were selected, area (A) representing the region of interest and area (B) representing the normal area. Area (B) was then divided by area (A). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated by comparing diagnoses made by elastography, strain ratio and final diagnoses.RESULTSSPL were shown to be benign in 49 patients and malignant in 123 patients. Elastography alone had a sensitivity of 99%, a specificity of 63%, and an accuracy of 88%, a PPV of 87% and an NPV of 96%. The best cut-off level of strain ratio to obtain the maximal area under the curve was 7.8 with a sensitivity of 92%, specificity of 77%, PPV of 91%, NPV of 80% and an accuracy of 88%. Another estimated cut off strain ratio level of 3.8 had a higher sensitivity of 99% and NPV of 96%, but with less specificity, PPV and accuracy 53%, 84% and 86%, respectively. Adding both elastography to strain ratio resulted in a sensitivity of 98%, specificity of 77%, PPV of 91%, NPV of 95% and accuracy of 92% for the diagnosis of SPL.CONCLUSIONCombining elastography to strain ratio increases the accuracy of the differentiation of benign from malignant SPL.

Ultrasonic Elastography Research Based on a Multicenter Study: Adding Strain Ratio after 5-Point Scoring Evaluation or Not.

BackgroundThis study aimed to confirm whether strain ratio should be added after evaluation of lesions with 5-point elasticity scoring for differentiating benign and malignant breast lesions on ultrasonographic elastography(UE).Materials and MethodsFrom June 2010 to March 2012, 1080 consecutive female patients with breast lesions were recruited into a multicenter retrospective study, which involved 8 centers across China. Each institutional ethic review board approved the study, and all the patients gave written informed consent. All the patients underwent the UE procedure and the strain ratios were calculated and the final diagnosis was made by histological findings. The sensitivity, specificity, accuracy, PPV and NPV were calculated for each of the two evaluation systems and the areas under the ROC curve were compared.ResultsThe strain ratios of benign lesions (mean, 2.6±2.0) and malignant lesions (mean,7.9±5.8) were significantly different (p <0.01). When the cutoff point was 3.01, strain ratio method had 79.8% sensitivity, 82.8% specificity, and 81.3% accuracy, while the 5-point scoring method had 93.1% sensitivity, 73.0% specificity, and 76.8% accuracy. The areas under the ROC curve with the strain ratio method and 5-point scoring method were 0.863 and 0.865, respectively(p>0.05). The strain ratio method shows better a diagnosis performance of the lesions with elasticity score 3 and 4.ConclusionsAlthough the two UE methods have similar diagnostic performance, separate calculation of the strain ratios seems compulsory, especially for the large solid breast lesions and the lesions with elasticity score 3 and 4.

Elastography in pancreatic solid tumours diagnoses.

IntroductionPancreatic solid tumour diagnoses remain a challenge for modern medicine. However, using endosonography together with elastography helps to examine the elasticity of tissues and therefore may allow definition of the nature of pancreatic tumours.AimTo evaluate the usefulness of elastography with the strain ratio method and quantitative evaluation of pancreatic solid tumours.Material and methodsA total of 54 patients with pancreatic solid tumours were treated with ultrasound endosonography with fine-needle aspiration biopsy. The control group contained 26 patients with normal pancreas. Pancreatic solid tumours and normal pancreas were analysed with elastography and elasticity evaluation of the interest area (A), reference (B), and the strain ratio factor (B/A). Postoperative histopathological or cytological examinations were the final diagnoses. Both postoperative and cytological diagnoses were compared with average elasticity parameters (A) and strain ratio factors (B/A).ResultsAverage elasticity parameters (A) and the strain ratio factors (B/A) were: 0.025% (0.01–0.05%) for malignant process, and (B/A) 33.93 (18.23–75.45); (A) – 0.26% (0.14–0.35%), and (B/A) 5.35 (3.47–7.8) for inflammatory process; (A) 0.54% (0.35–0.82%), and (B/A) 1.79 (1.02–2.05) for normal pancreatic tissue.ConclusionsMalignant tumours have higher tightness factor compared to inflammatory tumours and normal pancreatic tissue. Elasticity parameters reach the highest levels in normal pancreatic tissue, lower in inflammatory tumours, and the lowest in malignant tumours.

Comparative study on the clinical value of the elastic grades score evaluation method and ultrasound elasticity imaging strain ratio method in identifying thyroid nodules

Objective To investigate and compare the clinical value of the elastic grades score evaluation method and ultrasound elasticity imaging strain ratio method in identifying thyroid nodules. Methods A total of 120 cases confirmed by operation and pathology of the patients with thyroid nodules in our hospital were underwent ultrasound elasticity imaging detection,the thyroid nodules were identified with the elastic grades score evaluation method and ultrasound elasticity imaging strain ratio method respectively, and were compared with pathological results separately. Results The sensitivity,specificity and accuracy rate were 79.4%,81.3%, 81% with the elastic grades score evaluation method, the sensitivity, specificity and accuracy rate were 91.2%, 90.3%,93.3% with ultrasound elasticity imaging strain ratio method, of which was significantly higher with ultrasound elasticity imaging strain ratio method than with the elastic grades score evaluation methodby statistical analysis(χ2= 28.170,P= 0.000;χ2= 34.219,P= 0.000;χ2= 17.928,P= 0.000). Conclusion Ultrasound elastography strain ratio and rating score evaluation method can be used as an effective method in differentiating malignant from benign thyroid nodules, which can effectively improve the accuracy rate of the differential diagnosis of thyroid nodules and effectively remedy the diagnostic error band to cognitive differences with traditional ultrasound evaluation. The method of ultrasound elastography strain rate ratio was better with advantages of easy to operate, easy to learn and master, and easily accepted by patients, which is worthy of clinical application. Key words: Ultrasonography; Elasticity imaging; Strain rate; Score evaluation method; Thyroid nodules

Diagnosis of solid breast lesions by elastography 5-point score and strain ratio method

PurposeTo compare the diagnostic performance of 5-point scoring system and strain ratio by sonoelastography in the assessment of solid breast lesions. Material and methodsOne hundred and eighty-seven solid masses in 155 patients were scanned by two-dimensional ultrasonography and sonoelastography. Elasticity scores were determined with a 5-point scoring method, and the strain ratio was based on the comparison of the average strain measured in the lesion with the adjacent breast tissue in the same depth. Pathological results were taken as gold standards to compare the diagnostic efficacy of two methods with clinical diagnostic test and receiver operating characteristic (ROC) curves. ResultsAmong 187 lesions, 130 were benign and 57 were malignant. The mean scores (1.62±0.69 vs 4.07±0.26, P<0.05) and strain ratios (2.06±1.27 vs 6.66±4.62, P<0.05) were significantly higher of malignant than benign lesions. The area under the curve for the 5-point scoring system and for strain ratio-based elastographic analysis was 0.892 and 0.909, respectively (P>0.05). For 5-point scoring, sonoelastography had 84.2% sensitivity, 84.6% specificity, 84.5% accuracy, 70.6% positive predictive value and 92.4% negative predictive value. When a cutoff point of 3.06 was used, sensitivity, specificity, accuracy, positive and negative predictive values were 87.7%, 88.5%, 88.2%, 76.9% and 94.3%, respectively for the strain ratio (P>0.05). ConclusionsThe 5-point scoring system and strain ratio has similar diagnostic performance, and the strain ratio could be more objective to differentiate the masses when those masses were difficult to be judged by using 5-point scoring system in sonoelastographic images.

Contribution of Micro Structure to Repeated Loading Effect on Compacted Allophaneous Volcanic Ash Soil

ABSTRACT The hardening effect and delay of propagation of pore water pressure were observed in repeated loading test on the specimens of compacted allophaneous volcanic ash soils under undrained condition. These phenomena occurred even in the specimen whose degree of saturation was higher than 95%. This research was carried out to investigate the mechanism of hardening effect of repeated loading on the above highly saturated specimens from the viewpoint on the relation between hardening effect and micro structure. Then, the following results were obtained. (1) The difference of micro structure influenced not only on the behavior of soil in the standard undrained triaxial compression test but also on that in the undrained repeated loading test. (2) Undrained repeated loading had both of hardening and softening effects. (3) The hardening effect was given by the gradual increase in contact area between soil particles, anisotropy and density resulted from deformation and fracture of soil peds and compression of residual micro air bubbles during repeated loading. (4) To obtain the yielding repeated load ratio, the strain ratio (recoverable strain/irrecoverable strain) method was more favorable for allophaneous volcanic ash soils than the strain rate method. The yielding repeated load ratio was 0. 4 through all kinds of specimens used in this research.