Shear wave elastography evaluation in pediatric testicular microlithiasis: a comparative study

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.

Shear wave elastography for the evaluation of testicular salvage after testicular torsion

The aim of this study was to assess the utility of shear wave elastography in the follow-up of testicular detorsion, evaluate long-term outcomes, and explore its relationship with parameters such as tissue stiffness values, pain duration, and torsion type. Elastography examinations were independently performed by two radiologists to evaluate patients who presented to our hospital for follow-up after being diagnosed with testicular torsion and age-matched controls. Inter-observer variability of the mean testicular tissue elasticity was excellent (Intraclass correlation coefficient: 0.939, p < 0.001). Median time between testicular detorsion and follow-up ultrasound examination was 18 months (range, 11-36 months). Torsion side, torsion degree, and pain duration were recorded, and testicular volumes were calculated. The study population comprised 24 patients (48 testes) with a mean age of 21.1 ± 7.8 years. The mean testicular volume was measured as 12.3 ± 5.4 ml for the testicular salvage group, 13.9 ± 3.8 ml for the contralateral testes, and 13.7 ± 2.7 ml for the control group (p = 0.553). The mean testicular speed mode values were higher in the testicular salvage group (1.34 ± 1.21 m/s) compared with the contralateral testes group (1.00 ± 0.08 m/s), and the control group (1.01 ± 0.06 m/s), however there was no statistically significant difference between the three groups (p = 0.861). While testicular atrophy was detected in three patients, an intraparenchymal wedge-shaped focal hypoechoic area developed after torsion in a further three patients. The elastography examination for focal hypoechoic areas revealed an increase or decrease in tissue stiffness compared to the normal parenchyma. The tissue stiffness values of the testicular salvage group were higher in complete torsion compared to incomplete torsion. The elastography method contributes to other imaging methods in distinguishing focal lesion areas that can be seen after testicular torsion from malignant conditions. Elastography presents as a feasible and practical complementary modality for the follow-up of testicular salvage after torsion.

Imaging of Pediatric Testicular and Para-Testicular Tumors: A Pictural Review

Pre- and post-pubertal testicular tumors are two distinct entities in terms of epidemiology, diagnosis and treatment. Most pre-pubertal tumors are benign; the most frequent are teratomas, and the most common malignant tumors are yolk-sac tumors. Post-pubertal tumors are similar to those found in adults and are more likely to be malignant. Imaging plays a pivotal role in the diagnosis, staging and follow-up. The appearance on ultrasonography (US) is especially helpful to differentiate benign lesions that could be candidates for testis-sparing surgery from malignant ones that require radical orchidectomy. Some specific imaging patterns are described for benign lesions: epidermoid cysts, mature cystic teratomas and Leydig-cell tumors. Benign tumors tend to be well-circumscribed, with decreased Doppler flow on US, but malignancy should be suspected when US shows an inhomogeneous, not-well-described lesion with internal blood flow. Imaging features should always be interpreted in combination with clinical and biological data including serum levels of tumor markers and even intra-operative frozen sections in case of conservative surgery to raise any concerns of malignity. This review provides an overview of imaging features of the most frequent testicular and para-testicular tumor types in children and the value of imaging in disease staging and monitoring children with testicular tumors or risk factors for testicular tumors.

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.

Testicular stiffness in varicocele: evaluation with shear wave elastography

PURPOSE

This study was conducted to evaluate the potential role of shear wave elastography (SWE) in the evaluation of testes in patients with varicocele.

METHODS

A total of 116 testes of 58 patients with left-sided varicocele and 58 testes of 29 age-matched healthy controls were included in the study. The patients' testes were classified into groups A (normospermic) and B (oligospermic) based on the presence of oligospermia. The mean SWE values and volume of the testes with varicocele were compared with the contralateral normal testes of the patients and the testes of healthy controls.

RESULTS

The mean SWE value of the left testes in groups A (4.77±1.16 kPa) and B (6.15±1.96 kPa) exceeded that of the healthy controls (3.79±0.94 kPa) (P<0.001). The mean SWE value of the left testes in group B (6.15±1.96 kPa) exceeded that of group A (4.77±1.16 kPa) (P=0.002). No correlation was observed between testicular stiffness and the grade of varicocele (r=0.102, P=0.423).

CONCLUSION

The testes with varicocele were stiffer than the contralateral testes and the testes of healthy controls, and SWE might play an auxiliary role to conventional ultrasonography in assessing pathologic alterations in the testis owing to varicocele.

Normal Changes and Ranges of Pediatric Testicular Volume and Shear Wave Elasticity

To determine normal ranges for pediatric testicular volume and stiffness values (SV) on ultrasonography (US) and shear wave elastography (SWE) with respect to age and weight, testicular US scans (including SWE) of children (<10 y old) performed from February 2015 to January 2017 were retrospectively reviewed; grossly normal testes or testes with small hydroceles were included. Correlations between age weight, and testicular volume or SV were evaluated. Among a total of 52 boys (1-92 mo, median = 23.5 mo), there were positive correlations between testicular volume and age (R² = 0.451, p < 0.001) and weight (R² = 0.515, p < 0.001). Testicular SV was negatively correlated with age (R² = 0.166, p = 0.051) and weight (R² = 0.372, p = 0.049). Therefore, SV decreases while volume increases with increasing weight in testes of healthy children. Normal ranges for testicular volume and SV in children younger than 10 y are reported.

A comparative study of shear wave elastography in the evaluation of undescended and retractile testes in a pediatric population

PURPOSE

To evaluate the diagnostic value of shear wave elastography (SWE) in the evaluation of undescended and retractile testes (RT) in a pediatric population.

METHODS

We prospectively evaluated a total of 37 undescended testes (UDT), 15 RT, and 56 normal testes using SWE. The stiffness values were recorded for speed (m/s) and elasticity (kPa), and the mean stiffness values of groups were compared with each other.

RESULTS

The mean stiffness values of the UDT (13.80 ± 4.14 kPa, 2.14 ± 0.29 m/s) were higher than the mean SWE values of the normal testes (7.44 ± 2.11 kPa, 1.57 ± 0.21 m/s) (p < 0.0001). The mean stiffness values of the RT (9.64 ± 3.71 kPa, 1.75 ± 0.35 m/s) exceeded those of the normal testes (p = 0.004 for elasticity and p = 0.02 for speed). The mean stiffness value of the UDT was higher than the retractile ones (p < 0.0001 for elasticity and speed).

CONCLUSION

The higher stiffness values of the UDT and the RT compared to normal testes are likely reflective of underlying pathological alterations; hence, we suggest that SWE might serve as a valuable adjunct for the management of UDT and RT by assessing and monitoring ultrastructural changes.

Ultrasound Evaluation of Testicular Volume in Patients with Testicular Microlithiasis

Purpose

Ultrasonography is a useful tool to measure testicular volume. According to the European Society of Urogenital Radiology, the combination of testicular atrophy and testicular microlithiasis (TML) is a risk factor for testicular cancer. Testicular atrophy is defined as a volume of less than 12 ml. The aim of this study was to compare testicular volume in patients with TML to patients with normal testicular tissue.

Materials and Methods

From 2013 to 2015 we included a total of 91 adult patients with TML, and 91 adult patients with normal testicular tissue as a control group. All patients underwent scrotal B-mode ultrasound investigation including measurement of width, length and height in both testicles. Testicular volume was calculated using the formula π/6×length×height×width.

Results

The median age for patients with TML was 48 years (range: 19-94 years), and 48 years (range: 20–75 years) in patients with normal tissue. No statistically significant difference was found between total testicular volume (both testes) >30 ml in patients with TML compared to patients without (OR 0.77 (95% CI 0.43-1.38, p=0.37). However, patients with TML tended to have lower testicular volume compared to patients without TML, when investigating testicular volume below 12 ml.

Conclusion

Overall, no association was found between testicular volume and TML, but there was a trend indicating that severe atrophy is often seen in patients with TML compared to patients without TML. However, a significant difference was only found in testicular volume ≤8 ml.