Ultrasonography of the scrotum: Revisiting a classic technique

Conventional US is the primary imaging modality for the evaluation of the scrotum, due to its high resolution, availability, cost-effectiveness and absence of ionizing radiation. Grayscale and color Doppler US provide a comprehensive assessment of scrotal diseases. The technique represents the mainstay for imaging of acute scrotum. US is highly accurate in the detection, localization and characterization of scrotal masses. Multiparametric US, including conventional US, contrast-enhanced US and tissue elastography has improved the diagnostic performance of the technique in the assessment of testicular diseases. MRI represents a valuable supplemental imaging tool for the investigation of scrotal pathology, mainly recommended in cases of indeterminate US findings. Recommendations recently issued by the European Society of Urogenital Radiology Scrotal and Penile Imaging Working Group (ESUR-SPIWG) refer to the use of scrotal sonography for the evaluation of pathologic entities, including testicular microlithiasis, small, non-palpable incidentally detected testicular masses, varicocele and scrotal trauma. In this review, the technical specifications for scrotal US and the normal sonographic findings are presented. Grayscale and color Doppler US findings of common acute scrotal diseases and scrotal masses are discussed. The complimentary role of multiparametric US and scrotal MRI is addressed. ESUR-SPIWG's guidelines are also reviewed.

The Diagnostic Accuracy of Testicular Torsion by Doctors on Duty Using Sonographic Evaluation with Color Doppler

As testicular torsion is a medical emergency, it requires quick diagnosis and treatment. Color Doppler ultrasound (CDUS) is useful for the diagnosis of testicular torsion. An accurate diagnosis can be difficult when CDUS indicates the preservation of blood flow in the testis. We examined the accuracy of testicular torsion diagnosis in patients with acute scrotum made by doctors on duty using CDUS. The subjects included 26 patients who visited our department between January 2016 and June 2018 presenting with acute scrotal pain. Patients were placed into one of three groups based on testicular blood flow evaluated by CDUS. The first group had no testicular blood flow, the second had diminished blood flow, and the last group had normal or increased blood flow. Patients were also diagnosed through scrotal exploration. Finally, patients were further divided into two groups identified by CDUS frequency utilized during diagnosis (12 MHz groups and ≤8 MHz groups), and the diagnostic accuracy of the two groups was compared. Characterizing torsion by either the absence of or diminished, testicular blood flow in the CDUS evaluation, the sensitivity and specificity of the CDUS performed by doctors on duty accounted for 69.2% and 53.8%, respectively. No improvement in diagnostic accuracy was evident despite the usage of a 12-MHz ultrasonic transducer. In this study, the sensitivity of CDUS performed by doctors on duty was about 70%, suggesting that scrotal exploration should be performed promptly even if testicular blood flow is observed and testicular torsion is suspected from medical history and body findings.

When to ask for an MRI of the scrotum

Background

Multiparametric MRI (mpMRI) of the scrotum has been established as a useful second‐line diagnostic tool for the investigation of scrotal diseases. Recently, recommendations on clinical indications for scrotal MRI were issued by the Scrotal and Penile Imaging Working Group of the European Society of Urogenital Radiology.

Objective

To update current research on when to ask for an MRI of the scrotum.

Methods

PubMed database was searched for original articles and reviews published during 2010–2021.

Results

Eighty‐three articles fulfilled the search criteria. Scrotal MRI is mainly recommended after inconclusive US findings or inconsistent with the clinical examination and should be asked in the following cases: differentiation between intratesticular and paratesticular lesions (in rare cases of uncertain US findings), characterization of paratesticular and intratesticular lesions (when US findings are indeterminate), discrimination between germ cell and sex cord‐stromal testicular tumors, local staging of testicular malignancies (in patients planned for testis‐sparing surgery), differentiation between seminomas and non‐seminomatous tumors (when immediate chemotherapy is planned and orchiectomy is delayed), assessment of acute scrotum and scrotal trauma (rarely needed, in cases of non‐diagnostic US findings) and detection and localization of undescended testes (in cases of inconlusive US findings). Although preliminary data show promising results in the evaluation of male infertility, no established role for mpMRI still exists.

Conclusion

Multiparametric MRI of the scrotum, by assessing morphologic and functional data represents a valuable problem‐solving tool, helping to improve our understanding on the nature of scrotal pathology and the process of spermatogenesis. The technique may improve patient care and reduce the number of unnecessary surgical procedures.

Suspected testicular torsion in children: diagnostic dilemma and recommendation for a lower threshold for initiation of surgical exploration

Purpose

Testicular torsion (TT) represents a clinical challenge that needs emergency surgical assessment. It is common to have negative scrotal exploration due to confounding symptoms and signs which makes it sometimes difficult to differentiate from similar surgical emergencies that do not warrant surgery. At the same time, several occasions of misdiagnoses or late interventions occur with devastating effects. We aim at delineating the significance of the different clinical, laboratory, and radiological variables in the detection of TT.

Methods

We retrospectively reviewed the charts of 52 patients who were surgically explored with a preoperative working diagnosis of suspected TT in our center over the period from 2011 to 2015. All the patients were examined by pediatric surgeons in the emergency room and had undergone ultrasound imaging of the testes. The ultrasound images were retrospectively reviewed by a pediatric radiologist who was blinded to the intraoperative findings. Univariate and multivariate and logistic regression analyses were performed.

Results

Of the studied group of patients, the majority (84.6%) had TT upon surgical exploration. The most frequently presented symptom was pain (80.8%), and only a minority (11.5%) presented with vomiting. Radiological findings with the highest sensitivity were heterogeneous echogenicity in favor of TT and enlarged epididymis indicating that TT is unlikely. However, the predictability of TT by any of the assessed clinical and imaging factors was statistically insignificant.

Conclusion

It is important to gather all relevant data from clinical, laboratory, and imaging sources when assessing pediatric patients with suspected TT given the inaccuracy of each single one of them if used alone. Keeping this in mind, Doppler ultrasound has a significant role to aid in the accuracy of the diagnosis and hence the appropriate decision-making thereafter. However, we found no single clinical or imaging sign that is sensitive enough to prove or rule out TT. Therefore, surgical exploration should take place in a timely manner. Moreover, further research is necessary to construct scoring systems where different predictors collectively have higher reliability.

Clinical application of neutrophil CD64 quantification for differential diagnosis of acute scrotum

The management of acute scrotum can be challenging, especially in infants or patients with a neurological or neurodevelopmental disorder in whom presentation, diagnosis and definitive management tends to be delayed. This leads to poor outcomes, such as loss of the affected testis. Here we present two cases of testicular torsion in patients with neurodevelopmental disorders, and a further two cases of epidydimo-orchitis in whom measurement of CD64 expression on neutrophils was helpful for differential diagnosis. These data suggest that the levels of expression of CD64 by neutrophils, known as a marker of infection, could also be useful for differentiating between testicular torsion and infection in acute scrotum.

MR imaging of scrotum

Magnetic resonance (MR) imaging of the scrotum has been used as a valuable supplemental diagnostic modality in evaluating scrotal pathology, mostly recommended in cases of inconclusive sonographic findings. Because of the advantages of the technique, MR imaging of the scrotum may provide valuable information in the detection and characterization of various scrotal diseases. The technique may accurately differentiate intratesticular from extratesticular mass lesions and provide important information in the preoperative characterization of the histologic nature of scrotal masses. An accurate estimation of the local extent of testicular carcinomas in patients for whom testis-sparing surgery is planned is possible.

Development and initial validation of a scoring system to diagnose testicular torsion in children

PURPOSE

Testicular torsion is a surgical emergency requiring prompt intervention. Although clinical diagnosis is recommended, scrotal ultrasound is frequently ordered, delaying treatment. We created a scoring system to diagnose testicular torsion, decreasing the indication for ultrasound.

MATERIALS AND METHODS

We prospectively evaluated 338 patients with acute scrotum, of whom 51 had testicular torsion. Physical examination was performed by a urologist, and all patients underwent scrotal ultrasound. Univariate analysis and logistic regression were performed, and a scoring system for risk stratification of torsion was created. Retrospective validation was performed with 2 independent data sets.

RESULTS

The scoring system consisted of testicular swelling (2 points), hard testicle (2), absent cremasteric reflex (1), nausea/vomiting (1) and high riding testis (1). Cutoffs for low and high risk were 2 and 5 points, respectively. Ultrasound would be indicated only for the intermediate risk group. In the prospective data set 69% of patients had low, 19% intermediate and 11.5% high risk. Negative and positive predictive values were 100% for cutoffs of 2 and 5, respectively (specificity 81%, sensitivity 76%). Retrospective validation in 1 data set showed 66% of patients at low, 16% intermediate and 17% high risk. Negative and positive predictive values for cutoffs of 2 and 5 were 100% (specificity 97%, sensitivity 54%). The second retrospective data set included only torsion cases, none of which was misdiagnosed by the scoring system.

CONCLUSIONS

This scoring system can potentially diagnose or rule out testicular torsion in 80% of cases, with high positive and negative predictive values for selected cutoffs. Ultrasound orders would be decreased to 20% of acute scrotum cases. Prospective validation of this scoring system is necessary.