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

The clinical value of ultrasound in assessing ovarian strangulation in female infants and toddlers with ovarian hernia

Objective

To explore the clinical value of ultrasound examination in evaluating the presence of ovarian torsion in female infants with inguinal ovarian hernia.

Methods

We conducted a retrospective analysis of 91 cases of ovarian hernia diagnosed by ultrasonography at our institution. Among them, 6 cases were identified as ovarian strangulation, while 85 cases were classified as non-ovarian strangulation. All cases underwent high-frequency ultrasound examination. We analyzed whether there were differences in the associated factors between the two groups and compared the disparities in the urgency of surgery between the two groups.

Results

Significant differences were observed between the ovarian strangulation group and the non- strangulation group in terms of ovarian volume, ovarian blood flow, and the presence of incarceration. The need for emergency surgery was significantly associated with the presence of incarceration and ovarian torsion.

Conclusion

Ultrasound has good clinical value in diagnosing ovarian hernia and determining the presence of ovarian strangulation. It can assist clinical physicians in determining the timing of surgery for children with ovarian hernia.

Non-invasive evaluation of testicular torsion using ultrasound shear wave elastography: an experimental study

PURPOSE

The goal of this study was to examine changes in testicular stiffness at various intervals after the induction of testicular torsion, as well as to assess the predictive value of testicular stiffness for testicular spermatogenesis after torsion.

METHODS

Sixty healthy male rabbits were randomly assigned to one of three groups: complete testicular torsion, incomplete testicular torsion, or control. All rabbits underwent preoperative and postoperative scrotal ultrasonography, including shear wave elastography (SWE), at predetermined intervals. Changes in SWE values were analyzed and compared using repeatedmeasures analysis of variance. To assess the diagnostic performance of SWE in determining the degree of spermatogenic function impairment, the areas under the receiver operating characteristic curves (AUCs) were calculated.

RESULTS

SWE measurements in both central and peripheral zones of the testicular parenchyma affected by torsion demonstrated significant negative correlations with spermatogenesis, with coefficients of r=-0.759 (P<0.001) and r=-0.696 (P<0.001), respectively. The AUCs of SWE measurements in the central or peripheral zones of the torsed testicular parenchyma were 0.886 (sensitivity, 83.3%; specificity, 100%) and 0.824 (sensitivity, 83.3%; specificity, 73.3%) for distinguishing between hypospermatogenesis and spermatogenic arrest, respectively (P=0.451, DeLong test).

CONCLUSION

Variations in the stiffness of both central and peripheral regions of the testicular parenchyma correlate with the extent and duration of torsion, exhibiting a specific pattern. The "stiff ring sign" is the characteristic SWE finding associated with testicular torsion. SWE appears to aid in the non-invasive determination of the extent of spermatogenic damage in torsed testes.

[Inguinal and Scrotal Diseases in Children and Adolescents]

In children and adolescents, inguinal and scrotal diseases are relatively common, and imaging is very useful for the diagnosis and differential diagnosis of these diseases. Therefore, it is important to understand the imaging findings of these diseases. In this article, we classify these diseases into small testes, cryptorchidism, patent processus vaginalis, acute scrotum pain, trauma, testicular tumors, and others and describe their characteristic findings.

Microvascular imaging ultrasound (MicroV) and power Doppler vascularization analysis in a pediatric population with early scrotal pain onset

INTRODUCTION

The power Doppler is a useful tool in the evaluation of pediatric acute scrotal pain. Nonetheless, it may have some inherent limitations in scrotal vascularization analysis, potentially causing unnecessary surgery. The microvascular imaging ultrasound (MicroV) is an innovative Doppler technique able to improve the detection of very low flow. This retrospective study aims to compare both power Doppler and MicroV in the evaluation of a pediatric population with early-stage scrotal pain onset, first in testis vascularization analysis, and second in their diagnostic performances.

MATERIALS AND METHODS

69 patients met the following inclusion criteria, age < 18-year-old, a clinical diagnosis of acute scrotal disease, pain onset ≤ 6 h, ultrasound examination (including B-mode, power Doppler, and MicroV), 3-months follow-up. For both power Doppler and MicroV, through a defined vascularization scale, it was evaluated the agreement in vascularization detection, and the sensitivity and specificity in US diagnostic abilities.

RESULTS

Retrospective diagnoses were of 8 testicular torsion, 15 orchi-epididymitis, and 46 children with other scrotal conditions. Power Doppler provided inconclusive US evaluation in 37.68% of the cases, while MicroV only in the 1.45% (p < 0.0001). Testicular torsion and orchi-epididymitis were identified, respectively, with MicroV in 100% (sensitivity, specificity, PPV, NPV, and accuracy of 100%) and 80% of patients (80% sensitivity, 100% specificity and PPV, 94.73% NPV, 95.65% accuracy); with power Doppler the identification was, respectively, of 87.5% (87.5% sensitivity, 100% specificity and PPV, 98.38% NPV and accuracy) and of 73.3% (73.33% sensitivity, 98.14% specificity, 91.66% PPV, 92.98% NPV, 92.75% accuracy).

CONCLUSIONS

Our findings indicate that MicroV is a reliable technique in vascularization detection of pediatric testes, being able also to detect vascularization in healthy testicles with no-flow at power Doppler examination. Moreover, MicroV could be a valuable ally in the US diagnostic of children with early-stage scrotal pain onset.

The Use of Doppler Ultrasound for Suspected Testicular Torsion: Lessons Learned from a 15-Year Multicentre Retrospective Study of 2922 Patients

BACKGROUND

Use of Doppler ultrasonography (DUS) for patients with suspected testicular torsion (TT) is highly controversial and remains debated, as it can delay surgery and its performance may vary.

OBJECTIVE

To assess the role, impact, safety, and performance of DUS in the management of patients with suspected TT before scrotal exploration.

DESIGN, SETTING, AND PARTICIPANTS

The TORSAFUF cohort retrospectively included patients older than 12 yr who underwent surgery for suspected TT in 14 academic hospitals between 2005 and 2019. Perioperative data and surgical and DUS reports were collected.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Clinical factors influencing DUS utilisation were analysed using multivariate logistic regression. The orchidectomy rate and delay to surgery were compared by group with and without DUS receipt using one-to-one propensity score (PS) matching to assess imaging safety. For the group with preoperative imaging, DUS performance was evaluated using a contingency table.

RESULTS AND LIMITATIONS

Overall, 2922 patients were included, of whom 956 (32.7%) underwent DUS before surgery. DUS was more likely to be performed in older patients (odds ratio [OR] 1.1, 95% confidence interval [CI] 1.1-1.2), those who experienced progressive onset of pain (OR 1.5, 95% CI 1.1-2), and patients who presented at the emergency department more than 6 h after their first scrotal symptoms (OR 2.3, 95% CI 1.9-2.8). After PS matching, DUS receipt was not significantly associated with orchidectomy but the delay to surgery was 1 h longer. DUS demonstrated strong sensitivity of 85.2% (95% CI 82.1-88.3%) and specificity of 52.7% (95% CI 48.8-56.6%). The performance was better for younger patients and for those with time since onset of pain of >6 h.

CONCLUSIONS

In this large retrospective study, DUS before surgery was safe, feasible, and useful in selected cases with suspected TT, but it should not delay or replace surgery in cases with a strong clinical suspicion.

PATIENT SUMMARY

We analysed the performance and safety of an ultrasound scan of the scrotum before surgery for patients with a suspected twisted testicle (TT). This scan before surgery was not associated with a higher risk of negative outcomes but was only moderate in accurately diagnosing TT. Surgery to correct TT should not be delayed.

Is Testicular Torsion a Real Problem in Pediatric Patients With Cryptorchidism?

Purpose: To present management and outcomes of patients with cryptorchidism suffering from testicular torsion. Methods: This is a retrospective review of pediatric patients with torsion of undescended testes, who were treated between 2009 and 2019. We recorded: the age, symptoms, duration of torsion, results of physical examination, surgery findings, and additional treatment. Additionally, an extensive online literature search, from 2015-2020, was performed to identify other similar case series. Results: We identified 9 boys with torsion of the undescended gonad, which represented 4.7% of all 192 boys with testicular torsion. The mean age of boys with torsion of undescended testis was 8.7 years. The mean duration of symptoms in our study group was long and it was up to 28.5 h. All patients had inguinal canal exploration. In eight cases, testicular necrosis and primary orchidectomy was performed. Furthermore, 45 cases were identified in the literature and reviewed. Conclusion: According to clinical experience and available studies, torsion of male undescended gonads is a comparatively rare condition. Nevertheless, diagnosis is still delayed and connected with inevitable orchidectomy.

"Follow the Fallopian tube": A technique to improve sonographic identification of ovaries in children

Ovary detection is the first step in confirming ovarian lesions. The daughter cyst sign is widely used for this purpose; however, it is not always applicable. Recent improvements in image resolution allow Fallopian tube delineation, which can serve as a guide to identify the ovary. This anatomical approach ("follow the Fallopian tube" technique) comprises three steps: (1) confirm the uterus; (2) follow the Fallopian tube; and (3) find the ovary. Other applications of this approach include the differentiation between nonovarian and ovarian masses and ruling out ovarian torsion and an auto-amputated ovary.

Acute scrotal pain in pediatric patients: diagnosis with an innovative Doppler technique (MicroV)

Acute scrotal pain is one of the most frequent symptoms in pediatric patients visited in the Emergency Department. Ultrasonography with color and power Doppler represents the first-line method that clinicians use to carry out the differential diagnosis between spermatic cord torsion and inflammation, but sensitivity and specificity are 63-100% and 97-100%, respectively; this variability may be related to operator's experience and testis vascular hemodynamics and also to machine performance and patient age. Recent technological innovations have made possible to create a new Doppler mode called ultrasound microvascular imaging. This technique exploits algorithms capable of separating low frequencies of static tissue artifacts from ones of very weak flows. It is known as MicroV (from Esaote) and Superb microvascular imaging (from Toshiba). It provides both macrocirculation vascular maps, as a typical Doppler feature, and microcirculation vascular maps. Furthermore, the use of background subtraction could improve the visibility of small vascular structures. We report a case of a pediatric patient suffering from acute scrotal pain assessed ultrasonographically with this innovative Doppler technique (MicroV) that may give more confidence in detecting testicular vascular signals if compared with traditional Doppler techniques.

The role of multiparametric ultrasound in the diagnosis of paediatric scrotal pathology

Multiparametric ultrasound (MPUS), combining conventional techniques (greyscale and colour Doppler ultrasound), ultrasound strain elastography, and contrast-enhanced ultrasound (CEUS), has been successfully used in the assessment of adult scrotal pathology. Contrast-enhanced ultrasound can confidently establish testicular tissue vascularity even in the small-volume paediatric testis. Elastography provides further assessment of tissue stiffness, potentially adding useful diagnostic information. In children, ultrasonography is particularly advantageous, being safe, radiation-free and negating the need for sedation or general anaesthesia during the imaging evaluation. In this review article, we aim to familiarise readers with the MPUS scanning protocol used for paediatric scrotal examination and provide an overview of scrotal MPUS features, with particular focus to clinical indications where MPUS may be advantageous over conventional ultrasonography.

Seeing the Unseen: Evaluating Testicular Vascularity in Neonates by Using the Superb Microvascular Imaging Ultrasound Technique

OBJECTIVES

To evaluate testicular vascularity in neonates by using the novel Superb Microvascular Imaging (SMI; Toshiba Medical Systems Corporation, Tokyo, Japan) ultrasound (US) technique and to compare this technique to conventional Doppler US techniques.

METHODS

A total of 140 healthy neonates between 2 and 60 days old who were admitted for routine screening were included in the study. However, in 9 cases, the Doppler study could not be completed. In the remaining 131 cases, color Doppler imaging (CDI), power Doppler imaging (PDI), Advanced Dynamic Flow (ADF; Toshiba Medical Systems), and monochrome SMI (mSMI) techniques were performed on a single representative testicle. Real-time cine images were captured for 5 to 10 seconds for each technique by using a high-frequency (7.2-14-MHz) linear transducer. The images were evaluated by 3 observers using a grading system to quantify the degree of vascularity and artifact interference.

RESULTS

A total of 131 testicles (74 right and 57 left) were evaluated, and vascularity was shown in 110 (84%) testicles with CDI, 109 (83%) with PDI, 94 (72%) with ADF, and 128 (98%) with mSMI by the consensus of all observers. The Doppler techniques were ranked from highest to lowest in the following order based on the degree of vascularity detected: mSMI > PDI > CDI > ADF (P < .001). Based on the presence of artifacts, the Doppler techniques were ranked as follows from high to low: ADF > CDI > PDI > mSMI (P < .001).

CONCLUSIONS

Superb Microvascular Imaging is a promising US technique that appears to detect testis vascularity better than conventional Doppler US techniques; however, further research is needed to support the results of this study.

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.

Severe forms of complete androgen insensitivity syndrome caused by a p.Q65X novel mutation in androgen receptor: Clinical manifestations, imaging findings and molecular genetics

Androgen insensitivity syndrome (AIS), a rare X-linked recessive genetic disorder with a normal 46, XY karyotype, is caused by defect of androgen receptor gene (AR) leading to resistance of the target tissues to androgenic hormones. There is a wide spectrum of clinical presentations of AIS, ranging from male infertility, hypospadias to completely normal female external genitalia. Here, we describe a 15-year old, phenotypically female individual, who visited our clinic for primary amenorrhea. The physical examination revealed normal female external genitalia, normal breast development, as well as sparse pubic hair and absence of axillary hair. A short blind vagina pouch was noticed in gynecological examination apart from the absence of cervix and uterus. Serum testosterone measured a considerable high level, and the karyotype was indicative of a normal male (46, XY). Transabdominal ultrasound (US) and magnetic resonance imaging (MRI) confirmed the absence of uterus, ovaries and fallopian tubes, only with a small blind-ending vagina observed. The clinical, laboratory, imaging, and genetic findings strongly suggest the diagnosis of complete androgen insensitivity syndrome (CAIS). Mutational analysis of the AR gene revealed a novel small insertion mutation c.192_193insTAGCAG(Q65X) in exon 1, which gives rise to a truncated nonfunctional protein, resulting in the loss of the remaining 856 C-terminus amino acid residues. This study indicates that US and MRI are two useful and noninvasive imaging methods for the diagnosis and evaluation of CAIS, and identification of this novel mutation expands the database of AR gene mutations. Furthermore, with the availability of the identification technology for this mutation, prenatal diagnosis could be offered for future pregnancies.

The ultrasonographic "whirlpool sign" in testicular torsion: valuable tool or waste of valuable time? A systematic review and meta-analysis

PURPOSE

A positive whirlpool sign (WS) is defined as the presence of a spiral-like pattern when the spermatic cord is assessed during ultrasonography (US), using standard, high-resolution ultrasonography (HRUS) and/or color Doppler sonography (CDS), in the presence of testicular torsion. The objective of this review was to assess the validity and accuracy of this sign by performing a comprehensive systematic literature review and meta-analysis.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, a comprehensive literature search was performed (August, 2017), using the following databases: BMJ Best Practice, Cochrane Library, Embase, PubMed, Scopus, and Web of Science. Selected studies were further assessed for relevance and quality using the Oxford 2010 Critical Appraisal Skills Program (CASP).

RESULTS

Of the studies assessed, a total of 723 participants were included, with a mean of 72.3 (SD 71.9) participants. Of the participants, 226 (31.3%) were diagnosed with testicular torsion (TT). Meta-analysis of the studies that provided sufficient data resulted in a pooled sensitivity and specificity of the WS of 0.73 (95% CI, 0.65-0.79) and 0.99 (95% CI, 0.92-0.99), respectively. Removal of all neonates increased the pooled sensitivity to 0.92 (95% CI, 0.70-0.98) while the pooled specificity remained almost unchanged at 0.99 (95% CI, 0.95-1.00). The estimated summary effect of all studies with sufficient data was 4.34 (95% CI, 1.01-7.67; n = 394; p = 0.001). A large degree of heterogeneity was suggested by an I² statistic of 88.27% (95% CI, 68.60-98.68%). Removal of neonatal subjects increased the estimated summary effect to 5.32 (95% CI, 1.59-9.05; n = 375; p = 0.001).

CONCLUSION

The WS, when correctly diagnosed, may be viewed as a very definitive sign for TT in the pediatric and adult populations. However, its role in neonates is limited.