Magnetic resonance imaging for locating nonpalpable undescended testicles: a meta-analysis

Construction and analysis of a joint diagnostic model of machine learning for cryptorchidism based on single-cell sequencing

BACKGROUND

Cryptorchidism is a condition in which one or both of a baby's testicles do not fully descend into the bottom of the scrotum. Newborns with cryptorchidism are at increased risk of developing infertility later in life. The aim of this study was to develop a novel diagnostic model for cryptorchidism and to identify new biomarkers associated with cryptorchidism.

METHODS

The study data were obtained from RNA sequencing data of cryptorchid patients from Nantong University Hospital and the Gene Expression Omnibus (GEO) database. Differential expression analysis was used to obtain differentially expressed genes (DEGs) between the control and cryptorchid groups. These DEGs were analyzed for their functions by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment using GSEA software. Random Forest algorithm was used to screen central genes based on these DEGs. Neuralnet software package was used to develop artificial neural network models. Based on clinical data, receiver operating characteristic (ROC) was used to validate the models. Single-cell sequencing analysis was used for the pathogenesis of cryptorchidism.

RESULTS

We obtained a total of 525 important DEGs related to cryptorchidism, which are mainly associated with biological functions such as supramolecular complexes and microtubule cytoskeleton. Random forest approach screening obtained eight hub genes. A neural network based on the hub genes showed a 100% success rate of the model. Finally, single-cell sequencing analysis validated the hub genes.

CONCLUSION

We developed a novel diagnostic model for cryptorchidism using artificial neural networks and validated its utility as an effective diagnostic tool.

Diagnosis, Classification, and Contemporary Management of Undescended Testicles

This article provides a comprehensive review regarding undescended testicles and other related conditions. We have included background information summarizing variable clinical presentations, epidemiology, and the implications of undescended testis (UDT) on fertility and malignancy risk. This article has an emphasis on the approach to diagnosis and surgical management for the UDT. The purpose of this review is to provide readers with useful clinical tools for assessing and treating patients with cryptorchidism.

Diffusion‐weighted imaging and conventional magnetic resonance imaging for detection of non-palpable undescended testis

Background

MRI is noninvasive imaging tool and does not imply ionizing radiation and applies multiplanes images, but it is sometimes less efficient in locating intraabdominal functioning testicles and it fails to locate most of the atrophied testicles. Our aim in this study was to assess the value of the combined conventional MR imaging and DWI in the detection of non-palpable undescended testes in pediatric patients and correlate the results with the laparoscopic finding.

Results

This prospective study was carried out from January 2020 to February 2022 on 60 pediatric patients with 68 non-palpable undescended testes referred from Urology department to the radiodiagnosis and medical imaging department at our institute for MR imaging evaluation of clinically diagnosed non-palpable undescended testis, and their age ranged from 6 months to 17 years with mean age of 4.24 ± 4.67 years. The conventional MRI sensitivity was 85.71%, specificity was 100%, NPV was 60%, and PPV was 100% with accuracy of 88.23%. The combined DWI and MRI sensitivity was 92.86%, specificity was 100%, NPV was 75%, and PPV was 100% with accuracy of 94.12%. DWI was able to detect all viable abdominal testes, while only detecting 26 (out of 28) inguinal testes. Combined assessment was able to detect all viable abdominal and inguinal testes.

Conclusions

Combined DWI with a high b value and conventional MRI including T1WI, T2WI and fat-suppression T2WI showed considerable diagnostic performance compared to conventional MRI alone improving the preoperative sensitivity and accuracy of detection of non-palpable undescended testes.

Management of high inguinal undescended testis: a review of literature

Background

Undescended testis is one of the most common paediatric surgical diagnoses. A lot of research has been done to date, to standardise the surgical management of intra-abdominal and extra-abdominal undescended testis. High inguinal undescended testis is a unique clinical encounter which demands additional surgical measures over conventional orchidopexy for better surgical results.

Main body of abstract

Open inguinal orchidopexy is a routine and quite straightforward operation for the majority of extra-abdominal undescended testis. However, there are instances in which the testis, even though situated in the inguinal region, poses a challenge for surgeons, to bring it in the scrotum by routine open inguinal orchiopexy. High inguinal testis can be defined as “any intra-canalicular testis present higher up in the inguinal canal and cannot be brought down easily to the scrotum by routine surgery as in standard orchiopexy (open or laparoscopy) and require additional lengthening manoeuvres”. It needs additional surgical lengthening manoeuvres like Prentiss, along with the steps of routine orchiopexy to bring it down in the scrotum. This review article describes the various nomenclatures of undescended testis, appropriate investigations and also various additional surgical measures in the management of difficult high inguinal testis.

Conclusion

High inguinal undescended testis poses a unique technical challenge even to well-experienced surgeons. It is very important that surgeons dealing with this condition are well aware of the anatomy in this region and also various different manoeuvres described to date to bring the testis down in the scrotum.

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.

Comparison of Two Types of Staged Laparoscopic Orchiopexy for High Intra-Abdominal Testes in Children: A Retrospective Study From a Single Center

Background: To evaluate the efficacy and safety of 2nd-stage laparoscopic traction orchiopexy (Shehata technique) compared to Fowler-Stephens (F-S technique) for high intra-abdominal testes (IATs) in children. Patients and Methods: We performed a retrospective review of all children (<14 years old) who underwent laparoscopic treatment of high IAT in the pediatric surgery center of Yijishan Hospital of Wannan Medical College from April 2016 to April 2020. Participants were divided into the Fowler-Stephens (F-S) group and Shehata group according to the surgical method. We collected the medical records of all children and analyzed them statistically. Results: In this study, 43 patients in our center received 2nd-stage laparoscopic surgical treatment. The results showed that there were 23 high IATs in 22 patients in the F-S group and 22 IATs in 21 patients in the Shehata group. All patients completed the operation successfully. No significant difference in operation time was noted between the two groups. There was no significant difference in the testicular atrophy rate between the two groups (P = 0.323). The testicular retraction rate of the F-S group was greater than that of the Shehata group (P = 0.04). Conclusion:The results of this study indicate that the application of assisted laparoscopic testicular traction technology can effectively retain the main blood supply of the testis and vas deferens with a high survival rate and clear advantages. The preliminary results show that the Shehata technique is safe, reliable and effective in the treatment of high IAT in children.

Non-palpable testis: is management consistent and objective?

INTRODUCTION

Diagnostic laparoscopy is recommended for boys with non-palpable testis (NPT) by American and European guidelines with the decision to pursue inguinal exploration based upon testicular vessel appearance. We hypothesized that management decisions are not consistent with the guidelines, and that assessment of vessels is subjective.

MATERIALS AND METHODS

Pediatric urologist management decisions were evaluated via an electronic survey to determine impact of contralateral testicle size, sonographic findings, surgeon region, and years in practice. In a digital image survey, surgeons were asked to interpret gonadal vessel status of 32 consecutive cases of NPT with absent abdominal testis as normal, atretic, or blind-ending to determine intra- and inter-rater reliability.

RESULTS

Of the 339 participants, more Europeans (49%) chose sonography as the first management step for NPT compared to US surgeons (12%). Regardless of sonographic findings, over 80% chose laparoscopy as the first step. In the presence of normal, atretic, and blind-ending vessels, the decisions to proceed with inguinal/scrotal exploration were 88%, 68%, and 17%, respectively. Contralateral hypertrophy and sonography findings had no significant impact on the decision to proceed with inguinal/scrotal exploration. The visual gonadal vessel survey showed surgeon interpretation of normal or blind-ending vessels had moderate inter-rater reliability. Surgeons did not agree on normal status 37% of the time and did not agree on atretic status 66% of the time. There was no statistical difference between European and US respondents (P = 0.23). Intra-rater reliability was fair for blind-ending vessels. When the first interpretation was blind-ending, the same surgeon changed interpretation of the same image 39% of the time. There was no statistical difference by years of practice.

CONCLUSIONS

Non-visualization of NPT on sonography and contralateral testis size had no significant impact upon management decisions. Surgeons chose to pursue inguinal/scrotal exploration based upon laparoscopic gonadal vessel status. However, these interpretations were subjective with low inter- and intra-rater reliability.

A clinical algorithm to diagnose differences of sex development

The diagnosis and management of children born with ambiguous genitalia is challenging for clinicians. Such differences of sex development (DSDs) are congenital conditions in which chromosomal, gonadal, or anatomical sex is atypical. The aetiology of DSDs is very heterogenous and a precise diagnosis is essential for management of genetic, endocrine, surgical, reproductive, and psychosocial issues. In this Review, we outline a step-by-step approach, compiled in a diagnostic algorithm, for the clinical assessment and molecular diagnosis of a patient with ambiguity of the external genitalia on initial presentation. We appraise established and emerging technologies and their effect on diagnosis, and discuss current controversies.

Clinical Consultation Guide on Imaging in Male Infertility and Sexual dysfunction

Imaging can benefit clinicians in evaluating men with infertility or sexual dysfunction by giving an overview of a patient's overall clinical condition before undertaking an invasive procedure. An understanding of the limitations and advantages of image modalities used in clinical practice will ensure that clinicians can optimize patient care with imaging when necessary. PATIENT SUMMARY: The objective of this article was to review the current literature on imaging modalities used for the diagnosis and management of male infertility and sexual dysfunction. An understanding of the advantages and limitations of these imaging modalities will ensure that clinicians can optimize patient care with imaging when necessary.

Imaging of the scrotum: beyond sonography

The aim of this article is to describe the role of second-level imaging techniques after an initial ultrasonography evaluation in the assessment of scrotal diseases. While ultrasonography remains central as the primary imaging modality for the evaluation of pathologic conditions of the scrotum, the role of magnetic resonance imaging continues to evolve: it can actually be valuable as a problem-solving tool when sonographic findings are equivocal or inconclusive. Magnetic resonance imaging of the scrotum may provide accurate detection and characterization of scrotal diseases, well depicting the precise location of scrotal masses (intratesticular or extratesticular) and reliably characterizing benign conditions simulating neoplastic processes, thus preventing unnecessary radical surgery. Advanced magnetic resonance techniques, most of all diffusion weighted imaging and magnetic resonance spectroscopy, play in the meanwhile a more significant role in evaluating scrotal diseases.

TEACHING POINTS

• Multiparametric ultrasonography usually represents the initial imaging modality for approaching scrotal diseases. • MRI is well established as a problem-solving tool for inconclusive sonographic findings. • Advanced MRI techniques can be successfully applied in scrotal pathology assessment. • MRI is valuable in differentiating benign conditions from neoplastic processes. • CT plays a role in trauma assessment and cancer staging alongside PET/CT.

Laparoscopic treatment of nonpalpable testicle. Factors predictive for diminished size

PURPOSE

The purposes of this study were to demonstrate the usefulness of laparoscopy in intraabdominal testicle (IAT) and to determine factors associated with diminished size during the final outcome after laparoscopic orchidopexy.

METHODS

This is a retrospective analysis of consecutive patients from 1999 to 2013 with a minimum follow-up of 1year. Patient and testicular factors were related to diminished size.

RESULTS

Sixty one patients, and 92 testicles were included. Median age at operation was 42months. Initially we found 66 normal sized testes (71.7%), 22 hypotrophic (23.9%) and four atrophic (4.3%). Eighty seven testes were brought down laparoscopically, 50 in one surgical stage and 37 in two stages. Mean follow-up was 40.2months and the final outcome was success: 73.5% and diminished size: 26.5%. Variables associated with diminished size were hypotrophy during initial evaluation, short spermatic vessels, section of spermatic vessels, two-stage surgery and tension to reach contralateral inguinal ring. Multivariate analysis showed that initial hypotrophy (odds ratio [OR] 4.96, confidence interval 95% [CI] 1.36-18.10) and tension to reach contralateral ring (OR 4.11, 95% CI 1.18-14.34) were associated with diminished size.

CONCLUSIONS

Laparoscopy is useful in treating IAT. Initial size and tension to reach contralateral ring are factors associated with diminished size.

Compensatory function of the remaining testis is dissociated in boys and adolescents with monorchidism

OBJECTIVE

Compensatory hypertrophy has been classically described in patients with monorchidism. However, it remains unclear whether there is a functional compensatory activity of the different cell populations. Our aim was to assess the functional capacity of the solitary testis in monorchid males from infancy through puberty in order to determine whether the remaining gonad is capable of compensating the functional activity of Sertoli and Leydig cells of the absent gonad.

DESIGN

In a retrospective, cross-sectional, analytical study performed at a tertiary paediatric public hospital, we included 89 boys with monorchidism and 358 healthy controls, aged 6 months-18 years. Testicular volume and circulating levels of reproductive hormones were compared between patients with monorchidism and normal boys. Serum anti-Müllerian hormone (AMH) and FSH were used as biomarkers of the functional mass of prepubertal Sertoli cells, whereas serum testosterone and LH were used as biomarkers of Leydig cells.

RESULTS

In the vast majority of the cases, the testicular volume of monorchid boys was smaller than the sum of the volume of both testes of healthy controls. Serum AMH was lower and FSH was higher in patients with monorchidism than in controls aged <3 and >13 years. Serum testosterone and LH did not differ significantly between patients and controls.

CONCLUSION

In boys and adolescents with monorchidism, there is a dissociated capacity of the remaining testis to compensate for the absence of the other gonad: while Leydig cell function is largely compensated, Sertoli cell proliferation and function was lower than in controls.

Unnecessary diagnostic imaging: a review of the literature on preoperative imaging for boys with undescended testes

Cryptorchidism or undescended testis is one of the most common pediatric disorders of the male endocrine glands and the most common genital disorder identified at birth. Ultrasound is commonly ordered for boys with undescended testes prior to referral to a surgical specialist, but its sensitivity and specificity is insufficient to reliably localize non-palpable testes and thus confers unnecessary costs to the patient and the healthcare system. We review the ability of ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) to reliably locate undescended testes and emphasize whether diagnostic imaging should change the decision to operate or the surgical approach for boys with cryptorchidism.

Current Management of Undescended Testes

Undescended testes (UDTs) are a relatively common finding in newborn males, especially in those born prematurely. Upon discovering a non-intrascrotal testis, it is important to determine whether the testis is palpable or non-palpable and whether the finding is unilateral or bilateral. Imaging should not be used in this workup, as no current modality has been shown to be adequately sensitive or specific to aid in management decisions. Patients with UDTs diagnosed after 6 months of age should be referred to a specialist for correction so that surgery may be performed within 1 year thereafter. This allows testes to descend spontaneously if they are to do so while facilitating early intervention to decrease the risk of subfertility and testicular malignancy for those patients in whom spontaneous descent does not occur. The surgical approach is often dependent on the location of the testis on physical exam. Most orchiopexies for palpable testes are performed through an inguinal incision, although a scrotal approach can be safely utilized depending on the testis position. Diagnostic laparoscopy is most often used for non-palpable testes, as it not only allows for the identification of an atrophic or absent testicle, but it also provides an opportunity to perform an orchiopexy simultaneously should a viable testis be found. Hormonal therapy is not recommended for treatment of UDTs due to its low success rate, the incidence of secondary re-ascent, and the possible detrimental effects on spermatogenesis. Finally, patients with bilateral non-palpable UDTs require a more extensive preliminary evaluation to rule out congenital adrenal hyperplasia (CAH) and disorders of sexual development (DSD). This involves serum electrolytes, karyotype analysis and hormonal testing including a serum müllerian inhibiting substance (MIS), in order to determine if testicular tissue is present and functional.

MR Imaging of the Penis and Scrotum

Traditionally, due to its low cost, ready availability, and proved diagnostic accuracy, ultrasonography (US) has been the primary imaging modality for the evaluation of scrotal and, to a lesser extent, penile disease. However, US is limited by its relatively small useful field of view, operator dependence, and inability to provide much information on tissue characterization. Magnetic resonance (MR) imaging, with its excellent soft-tissue contrast and good spatial resolution, is increasingly being used as both a problem-solving tool in patients who have already undergone US and as a primary modality for the evaluation of suspected disease. Specifically, MR imaging can aid in differentiating between benign and malignant lesions seen at US, help define the extent of inflammatory processes or traumatic injuries, and play a vital role in locoregional staging of tumors. Consequently, it is becoming more important for radiologists to be familiar with the wide range of penile and scrotal disease entities and their MR imaging appearances. The authors review the basic anatomy of the penis and scrotum as seen at MR imaging and provide a basic protocol for penile and scrotal imaging, with emphasis on the advantages of MR imaging. Pathologic processes are organized into traumatic (including penile fracture and contusion), infectious or inflammatory (including Fournier gangrene and scrotal abscess), and neoplastic (including both benign and malignant scrotal and penile tumors) processes.

Laparoscopic versus open orchiopexy in the management of peeping testis: a multi-institutional prospective randomized study

OBJECTIVE

Peeping testis is an inconsistently palpable/seen undescended testis that migrates back and forth at the internal inguinal ring. Both open and laparoscopic orchiopexy are effective forms of management. The present study aimed to evaluate the efficacy and safety of both approaches.

PATIENTS AND METHODS

Between September 2007 and January 2012, 46 peeping inguinal testes were randomly treated with either open (25 cases) or laparoscopic (21 cases) orchiopexy procedures. Spermatic vessels were preserved for all cases. Operative details, postoperative morbidity and final testicular site and size were recorded.

RESULTS

The median age of the children was 2.5 years (range 0.5-12.0). The follow-up period ranged from 1.0 to 5.5 years. Of these testes, 20 in the open surgery group and 19 in the laparoscopic group maintained correct intrascrotal position (P = 0.428). Re-do orchiopexy was indicated for two cases in the surgical group (P = 0.493). No cases of testicular atrophy or hernia were encountered.

CONCLUSION

Open and laparoscopic orchiopexy procedures for peeping testes are fairly comparable. However, laparoscopy is relatively more effective, as two re-do orchiopexies were required in the open surgical group.