Application of Quasistatic Ultrasound Elastography for Examination of Scrotal Lesions

Comparison Between Strain and 2D Shear Wave Elastography of Testes in Healthy Dogs

Sonoelastography is a rapid and non-invasive ultrasound-based technique to assess tissue elasticity. Interest in this technique's application in veterinary medicine is progressively increasing, with preliminary reports also available to assess canine testicular parenchyma abnormalities. Since elastographic techniques are different and it is of paramount importance to standardize procedures, this work aimed to compare two different elastographic techniques, SE and 2D SWE, on the same testes and compare the data with the current literature. Thirty healthy canine testes were included, and complete B-mode, color and power Doppler examinations were performed on each one. SE was performed qualitatively through an elastogram evaluation and semiquantitatively comparing the parenchyma with peripheral skin. 2D SWE was performed and m/s measurements were taken. Each measurement was collected in the cranial, middle and caudal portions, considering the sections above and below the mediastinum separately. The healthy testes appeared to be intermediate in stiffness with differences in the various portions for SE and expressed a mean value from 1.3 m/s to 1.4 m/s for 2D SWE, consistent with the previous literature. Considering the technical specifics of the software for the two elastography methods, both of them are valuable in assessing canine testis stiffness and are potentially clinically appliable.

The value of multimodal ultrasonography in the evaluation of late presenting testicular torsion in a rat experimental model

OBJECTIVE

To evaluate the value of multimodal ultrasonography (US) in a rat experimental torsion model after 6 h of torsion with different degrees.

METHODS

Twenty-one male rats were divided into three groups. Left testes of the rats were twisted around their vascular pedicle 360 degrees in group 1, 720 degrees in group 2, and 1080 degrees in group 3 and intact right testes of the rats were accepted as control group. Grey-scale US, superb microvascular imaging (SMI), colour Doppler ultrasonography (CDUS), strain elastography (SE), and two-dimensional (2-D) shear wave elastography (SWE) examinations were applied 6 h after torsion procedure and testes were removed for pathological evaluation.

RESULTS

Short-axis dimensions and volumes of the torsion side were higher than control testes. Lengths of the testes in the 3rd torsion group were smaller than the testes in groups 1 and 2 (P < 0.002). SMI was better than CDUS in recognizing blood flow in testicular tissue. Strain ratios were higher in group 1 and decreased with the increasing torsion degree. Emean and standard deviation (SD) measurements increased in the torsion side. Pathologically the mean testicular damage scores were statistically significant between torsion and control testes in all groups.

CONCLUSION

Our results showed that short-axis and volume measurements, SMI, 2D-SWE, and SE are effective in the evaluation and diagnosis of testicular torsion (TT).

ADVANCES IN KNOWLEDGE

Evaluation of affected testis and intact testis with multiparametric US in late presenting TT cases is more reliable than being dependent on a single sonographic modality.

Noncontact longitudinal shear wave imaging for the evaluation of heterogeneous porcine brain biomechanical properties using optical coherence elastography

High-resolution quantification of heterogeneous brain biomechanical properties has long been an important topic. Longitudinal shear waves (LSWs) can be used to assess the longitudinal Young's modulus, but contact excitation methods have been used in most previous studies. We propose an air-coupled ultrasound transducer-based optical coherence elastography (AcUT-OCE) technique for noncontact excitation and detection of LSWs in samples and assessment of the nonuniformity of the brain's biomechanical properties. The air-coupled ultrasonic transducer (AcUT) for noncontact excitation of LSWs in the sample has a center frequency of 250 kHz. Phase-resolved Doppler optical coherence tomography (OCT) was used to image and reconstruct the propagation behavior of LSWs and surface ultrasound waves at high resolution. An agar phantom model was used to verify the feasibility of the experimental protocol, and experiments with ex vivo porcine brain samples were used to assess the nonuniformity of the brain biomechanical properties. LSWs with velocities of 0.83 ± 0.11 m/s were successfully excited in the agar phantom model. The perivascular elastography results in the prefrontal cortex (PFC) of the ex vivo porcine brains showed that the Young's modulus was significantly higher in the longitudinal and transverse directions on the left side of the cerebral vessels than on the right side and that the Young's modulus of the PFC decreased with increasing depth. The AcUT-OCE technique, as a new scheme for LSW applications in in vivo elastography, can be used for noncontact excitation of LSWs in brain tissue and high-resolution detection of heterogeneous brain biomechanical properties.

Radiological Evidence of Testicular Damage in Severe Acute Respiratory Syndrome Coronavirus 2 Infection: A Sonoelastography's Potential Role

ABSTRACT

This preliminary study aimed to evaluate the possible damage to the male reproductive system that the severe acute respiratory syndrome coronavirus 2 virus causes by quantitatively measuring and comparing the tissue stiffness of the testis and epididymis with acoustic radiation force impulse sonoelastography in patients who have COVID-19 with a healthy control group. This prospective study was conducted between February and July 2021 with 65 cases. We used sonoelastography to evaluate male patients 18 years or older, who had applied to the urology clinic with nontesticular complaints, and were found to not have any underlying testicular pathology after a clinical-laboratory evaluation. The clinical-laboratory imaging findings and reverse transcription-polymerase chain reaction test results of all patients diagnosed with COVID-19 were reviewed from the hospital database. We measured the shear wave velocity values of the epididymis and the testes of 31 proven severe acute respiratory syndrome coronavirus 2 patients and 34 healthy subjects and compared them with an independent t test. For the patient and control group subjects, the mean age was 37.55 ± 13.08 (23-71) and 40.5 ± 16.25 (18-81) years, respectively. The mean shear wave velocity values of the left-right and bilateral testes and epididymis of the patient group were statistically substantially higher ( P ˂ 0.05) than in the control group. In the receiver operating characteristic analysis, when the cutoff values for the bilateral testes and epididymis were determined as 1.39 and 1.64 m/s, respectively, the AUC was 77% to 73.4%, the sensitivity was 87% to 74%, and the specificity was 65% to 62%. Our findings show that testicular and epididymal tissue stiffness increased in patients with COVID-19. We recommend adding sonoelastography to urogenital examinations of male reproductive system in patients who are recovering from COVID-19.

Ultrasound Elastography in Children

Ultrasound elastography is a novel ultrasound technique, being extensively researched in children in the last decade. It measures tissue elasticity with the observation of tissue response after an external stimulus. From research to clinical practice, ultrasound elastography has evolved significantly in liver fibrosis evaluation in children; however, several other applications of the technique are available in both clinical practice and research environments. Practically, in children any organ can be assessed, including the brain in early ages, along with muscle and connective tissue elasticity evaluation, spleen, kidney, skin, lymphatic tissue, etc. The elastography method, age, body mass index and technical points should be considered when performing ultrasound elastography. This review highlights its vast potential as a diagnostic tool in the pediatric population, where ultrasound is a dominant imaging tool; however, the indications and exam protocol for its clinical use in several fields in pediatrics have yet to be elucidated.

Gamut of Extratesticular Scrotal Masses: Anatomic Approach to Sonographic Differential Diagnosis

The commonly taught tenet that intratesticular lesions are always malignant and extratesticular scrotal lesions are always benign is a simplistic statement that erroneously minimizes the significance of extratesticular scrotal masses and their diagnosis. Yet, disease in the extratesticular space is commonly encountered by clinicians and radiologists and is often a source of uncertainty in diagnosis and management. Given the embryologically rooted complex anatomy of this region, a wide range of pathologic conditions is possible. Radiologists may not be familiar with some of these conditions; further, many of these lesions can have a specific sonographic appearance, allowing accurate diagnosis that can minimize surgical intervention. Lastly, malignancies can occur in the extratesticular space-although this is less common than in the testicles-and proper recognition of findings that warrant additional imaging or surgery is critical in optimizing outcomes. The authors present a compartmental anatomic framework for differential diagnosis of extratesticular scrotal masses and provide a comprehensive illustrative display of many of the pathologic conditions that can be encountered to familiarize radiologists with the sonographic appearances of these lesions. They also review management of these lesions and scenarios where US may not be definitive in diagnosis and selective use of scrotal MRI can be helpful. ^© RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Ultrasonographic manifestations and the effective diagnosis of epididymal leiomyosarcoma: Case report and systematic literature review

Background

Epididymal leiomyosarcoma is an extremely rare tumor. In this study, we describe the sonographic features of this uncommon tumor.

Methods

A case of epididymal leiomyosarcoma diagnosed at our institute was retrospectively analyzed. Ultrasonic images, noted clinical manifestations, treatment procedures, and pathology results were collected for this patient. The same information was collected from a systematic literature search on epididymal leiomyosarcoma, including the PUBMED, Web of Science and Google Scholar databases.

Results

The literature search resulted in 12 articles; we were able to extract data from 13 cases of epididymal leiomyosarcomatosis. The median patient age was 66 (35-78) years, and the average tumor diameter was 2-7 cm. All patients had unilateral epididymal involvement. The lesions were all solid, irregular-shaped in almost half of the cases, featured clear borders in six cases, and had unclear borders in four cases. The internal echogenicity was heterogeneous in the majority of lesions: six cases were hypoechoic (7/11) and three cases moderately echoic (3/10). Information on blood flow within the mass was provided in four cases, but all were noted with significant vascularity. Surrounding tissue invasion was discussed in 11 cases, with 4 featuring peripheral invasion or metastasis.

Conclusion

Epididymal Leiomyosarcoma demonstrates sonographic characteristics common to many malignant tumors, such as increased density, irregular shape, heterogeneous internal echogenicity, and hypervascular. Ultrasonography is helpful to differentiate benign epididymal lesions, and can provide some reference for clinical diagnosis and treatment. However, compared with other malignant tumors of the epididymis, it has no characteristic sonographic features,and pathological confirmation is required.

Elastographic Imaging of Anaplastic Seminoma of Testis With Its Ultrasound and Doppler Correlation: A Case Report

The commonest solid tumour in men between the ages of 15 and 44 is testicular cancer. Germ cell tumours, which are then subdivided into seminomatous and non-seminomatous tumours, are its primary histological kind. In the fourth decade of a man's life, seminoma accounts for 55% of testicular cancer. Anaplastic seminoma, which accounts for 5% to 15% of testicular seminoma, is an uncommon kind of seminoma. The anaplastic variant of classical seminoma is an uncommon type of seminoma. In order to increase confidence in diagnosing and differentiating benign from malignant lesions and localising lesions in the testis, tissue elastography has arisen as a definite, important supplementary method. We present a case report of anaplastic seminoma with its classical imaging findings on strain elastography and its correlation with ultrasound and doppler.

ACR Appropriateness Criteria® Newly Diagnosed Palpable Scrotal Abnormality

Palpable scrotal abnormalities are caused by a variety of disorders, ranging from indolent benign conditions to aggressive tumors, and infectious and vascular processes. In these patients the diagnostic workup typically begins with a complete clinical, history, and physical examinations, including analysis of risk factors. If imaging is required, ultrasound examination is the diagnostic modality of choice. In few select patients with very large scrotal masses, MRI may be appropriate. However, the use of gadolinium-based contrast should be evaluated critically depending on specific patient factors. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The usefulness of elastography in the evaluation and management of adult men with varicocele: A systematic review

Objective

To review the role of elastography in the evaluation and decision-making of adult, infertile men with varicocele.

Methods

A systematic search using the terms (Elastography) AND (Varicocele), (Stiffness) AND (Varicocele), (Elastography) AND (Male infertility) was performed in Pubmed/Medline. Studies reporting a) elastographic characteristics in varicocele-bearing comparing to normal testicles, and b) the correlation of elastography with varicocele grading, parameters of spermatogenesis, and outcomes of varicocele treatment were selected. Exclusion criteria were animal, adolescents, abstracts, and non-English language studies.

Results

In total, 453 articles were identified; 11 eligible studies were selected. Several modalities were used (shear wave elastography, strain elastography, quasistatic ultrasound elastography, acoustic radiation force impulse). Varicocele-bearing testicles have significantly different stiffness and elasticity in comparison to normal and non-varicocele testicles. Although not in full agreement, elastography readings are correlated with semen parameters. Conflicting results were reported regarding grading as most of the studies failed to demonstrate a significant correlation. Shear wave elastography showed a significant correlation with the improvement in semen parameters after varicocelectomy, but the association with pregnancy rates is unknown. Finally, no studies were identified comparing elastography with other modalities.

Conclusions

Elastography can detect changes in the architecture of varicocele-bearing testicles. Although the role of the modality in grading is uncertain, elastography showed a meaningful correlation with spermatogenesis parameters. Importantly, elastography readings could predict the improvement in semen parameters after varicocelectomy which is useful in terms of decision-making in infertile men with varicocele.

Abbreviations

ARFI: acoustic radiation force impulse; CDUS: colour Doppler ultrasonography; DWI: diffusion-weighted imaging; PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses; SWE: shear wave elastography; VC: varicocele.

Shear-wave elastography for the assessment of testicular involvement of hematologic malignancies in children and young adults: a feasibility study

Purpose

This study aimed to assess the feasibility of shear-wave elastography (SWE) for assessing the testicular involvement of hematologic malignancies in children and young adults.

Methods

Eight patients (mean age, 11.0 years; range, 0.8 to 20 years) with biopsy-confirmed testicular involvement of hematologic malignancy between January 2018 and December 2020 were retrospectively evaluated. Multiparametric ultrasound examinations, including grayscale, color Doppler ultrasonography (CDUS), and SWE, were performed. Stiffness was measured in the involved testicular area and contralateral normal parenchyma. If there was bilateral testicular involvement, the stiffness of the involved area and the adjacent normal echoic parenchyma was measured on one testis. The Mann-Whitney U test was used to compare stiffness values.

Results

On grayscale, the testicular lesions were noted as a solitary mass in one patient, multiple lesions in four patients, and diffuse involvement in three patients. On CDUS and SWE, all patients demonstrated increased vascularity, and the stiffness of the involved area was higher than the values of normal parenchyma (the involved area vs. normal parenchyma, 11.6 kPa [3.9-20.2 kPa] vs. 2.9 kPa [1.1-3.7 kPa], P=0.003). The ratio of stiffness between the involved area and normal parenchyma was 3.4, ranging from 1.9 to 5.1. One patient showed decreased stiffness on follow-up SWE after treatment (affected testis vs. normal testis: initial, 13.8 vs. 3.2 kPa; 1 year later, 2.2 vs. 2.4 kPa).

Conclusion

Increased testicular stiffness on SWE in children and young adults with hematologic malignancies suggests the possibility of testicular involvement.

A preliminary study of shear-wave elastography for the evaluation of varicocele in adolescents and young adults

PURPOSE

The purpose of this study was to use shear-wave elastography (SWE) to assess testicular stiffness changes during the Valsalva maneuver in adolescents and young adults with varicocele, to compare these changes according to clinical severity, and to evaluate the role of SWE in the diagnosis of varicocele.

METHODS

This study included patients undergoing testicular ultrasonography for the diagnosis of varicocele or for post-varicocelectomy follow-up between June 2016 and February 2017. Fifty-four testicles of 27 consecutive patients (mean age, 15.9 years) were classified by clinical grade (grade 0-3). Using SWE, mean testicular stiffness (Emean) was measured at rest and during the Valsalva maneuver. The correlations between multiple ultrasonographic parameters (volume asymmetry, Emean at rest, and absolute and percentage changes in Emean during the Valsalva maneuver) and clinical grade were assessed using the Spearman correlation test.

RESULTS

The Emean at rest was similar across clinical grades. During the Valsalva maneuver, increased testicular stiffness was frequently observed in patients with grade 2 or 3 varicocele but rarely observed in those with grade 0 or 1 varicocele. The changes in Emean were positively correlated with the clinical grade (all P<0.001), whereas the Emean at rest and volume asymmetry were not (all P>0.05).

CONCLUSION

A transient, reversible increase in testicular stiffness during the Valsalva maneuver was observed in adolescents with high-grade varicocele, and the degree of stiffness change was correlated with the clinical grade. Stiffness change identified using SWE during the Valsalva maneuver is a potential surrogate indicator of venous congestion.

Application of Shear Wave Elastography to Evaluate the Stiffness of Normal Testes and Inflammatory Epididymal Tail Masses

OBJECTIVE

This study aimed to investigate the application value of shear wave elastography in examining normal testes and inflammatory epididymal tail masses.

METHODS

We examined 110 healthy male volunteers (with a total of 220 testes) and 25 patients with epididymitis via conventional scrotal ultrasonography and shear wave elastography. The mean (Emean), minimal (Emin), maximal (Emax), and standard deviation (ESD) values of elasticity were acquired. The inflammatory masses were assessed at initial diagnosis, at weeks 1 and 2 of standard anti-inflammatory treatment, upon remission, and at 2 weeks after remission.

RESULTS

The Emean values of different regions in testes varied in the following order: center region (3.14 ± 0.35 kPa) < upper- or lower-pole capsule (upper, 3.94 ± 0.90 kPa; lower, 3.94 ± 0.97 kPa) < posterior capsule (5.96 ± 1.46 kPa) < anterior capsule (6.27 ± 1.58 kPa). The Emean value of the center of the testicular parenchyma in the short axis was significantly larger than that in the long axis (3.47 ± 0.32 vs 3.14 ± 0.35 kPa; P < 0.05). There were significant differences in the Emean value between inflammatory epididymal tail masses at initial diagnosis, at 1 and 2 weeks after treatment, upon remission, and at 2 weeks after remission (P < 0.05).

CONCLUSIONS

Shear wave elastography can be used to reflect the relative hardness of normal testes and inflammatory epididymal tail masses.

Progress in the Application of Ultrasound Elastography for Brain Diseases

Ultrasound (US) can be used to evaluate the brain structure and nervous system damage. Patients with neurologic symptoms need rapid, noninvasive imaging with high spatial resolution and tissue contrast. Magnetic resonance imaging is currently the most sensitive and specific imaging method for evaluating neuropathologic conditions. This approach does present some challenges, such as the need to transport patients who may be seriously ill to the magnetic resonance imaging suite and the need for patients to remain for a considerable time. Cranial US provides a very valuable imaging method for clinicians, which can make a rapid diagnosis and evaluation without ionizing radiation. The main disadvantage of cranial US is its low sensitivity and specificity for subtle/early lesions. In recent years, with the rapid development of anatomic and functional US technology, the practicability of US diagnosis and intervention has been greatly improved. Ultrasound elastography may have the potential to improve the sensitivity and specificity of various cranial nerve conditions. Ultrasound elastography has received considerable critical attention, and an increasing number of studies have recognized its critical role in evaluating brain diseases. At present, US elastography has been applied to the evaluation of traumatic brain injury, ischemic stroke, intraoperative brain tumors, and hypoxic ischemic encephalopathy. The latest animal experiments and human clinical trial developments in the applications of US elastography for brain diseases are summarized in this review.

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.

Elastography of focal testicular lesions: current concepts and utility

As a relatively new sonographic technique, tissue elastography has emerged as a qualitative and potentially quantitative adjunctive tool to provide additional information on tissue stiffness, aiming to further improve diagnostic confidence in discriminating benign from malignant focal testicular lesions. The purpose of this review is to provide an overview of the elastography techniques used to assess focal testicular lesions and their typical appearance on tissue elastography.

Ultrasonography of pediatric urogenital emergencies: review of classic and new techniques

Urogenital emergencies are fairly common in the pediatric population, and a timely and correct diagnosis is necessary to avoid possible future infertility. In this field, ultrasonography is essential, as it has the advantages of being radiation-free and readily accessible. In particular, a high-frequency transducer allows precise evaluation of the morphology and vascularity of the scrotum, which is on the surface of the body. Beyond conventional techniques, new advanced imaging techniques have been developed, including elastography and contrast-enhanced ultrasonography. However, several pitfalls remain in the diagnosis of urogenital diseases using ultrasonography. Thus, accurate knowledge and sufficient experience with the technique are essential for making a correct diagnosis. This review provides an overview of pediatric urogenital emergency pathologies and recent ultrasonography techniques.