MR imaging of testicular torsion: features of testicular hemorrhagic necrosis and clinical outcomes

Imaging of acute scrotal infections, complications and mimics

Infection of the scrotum and its contents is the most common cause of acute scrotum. Imaging plays an important role in evaluating disease extent, severity and its complications. Sonography is the modality of choice for imaging the acute scrotum. This pictorial review discusses the varied clinical and imaging features of scrotal infections and their complications, with correlative CT, when available.

Spin Trapping of Nitric Oxide by Hemoglobin and Ferrous Diethyldithiocarbamate in Model Tumors Differing in Vascularization

Animal tumors serve as reasonable models for human cancers. Both human and animal tumors often reveal triplet EPR signals of nitrosylhemoglobin (HbNO) as an effect of nitric oxide formation in tumor tissue, where NO is complexed by Hb. In search of factors determining the appearance of nitrosylhemoglobin (HbNO) in solid tumors, we compared the intensities of electron paramagnetic resonance (EPR) signals of various iron-nitrosyl complexes detectable in tumor tissues, in the presence and absence of excess exogenous iron(II) and diethyldithiocarbamate (DETC). Three types of murine tumors, namely, L5178Y lymphoma, amelanotic Cloudman S91 melanoma, and Ehrlich carcinoma (EC) growing in DBA/2 or Swiss mice, were used. The results were analyzed in the context of vascularization determined histochemically using antibodies to CD31. Strong HbNO EPR signals were found in melanoma, i.e., in the tumor with a vast amount of a hemorrhagic necrosis core. Strong Fe(DETC)2NO signals could be induced in poorly vascularized EC. In L5178Y, there was a correlation between both types of signals, and in addition, Fe(RS)2(NO)2 signals of non-heme iron-nitrosyl complexes could be detected. We postulate that HbNO EPR signals appear during active destruction of well-vascularized tumor tissue due to hemorrhagic necrosis. The presence of iron-nitrosyl complexes in tumor tissue is biologically meaningful and defines the evolution of complicated tumor-host interactions.

Functional Imaging of Testicular Torsion

This article discusses the current clinical role and scope of functional radionuclide imaging using testicular perfusion scintigraphy with 99mTc-pertechnetate in patients presenting with an acute hemiscrotum for an early and reliable diagnosis of testicular torsion. The technique of testicular perfusion scintigraphy is described, and the characteristic findings are detailed with examples. The imaging characteristics of the various phases of testicular torsion and its differentiation from epididymitis and/or epididymo-orchitis and the other related conditions presenting as an acute hemiscrotum are detailed. In some cases, further evaluation by SPECT imaging increases the clarity and accuracy of diagnosis and, on occasion, hybrid SPECT/CT in selected complicated cases improves the diagnostic yield of the perfusion scintigraphy. Ultrasonographic and color Doppler findings are described concurrently with the scintigraphic findings. The several case examples presented demonstrate the additional clinical benefit of complementing functional and structural imaging for improving the sensitivity, specificity and accuracy of testicular imaging in the diagnosis.

Epididymo-Orchitis Leading to Global Testicular Infarction in a Pediatric Patient - A Case Report

Epididymo-orchitis (EO) is a common urologic condition that rarely requires surgical intervention. Global testicular infarction is an exceedingly uncommon complication of EO and is thought to occur when severe epididymal edema compresses testicular vessels. We present a rare case of global testicular infarction secondary to EO in a 17-year-old boy. Predicting which cases of EO will progress to testicular ischemia is challenging, as no clear risk factors have been identified. Early recognition of testicular compromise requires a high degree of clinical suspicion and may provide the opportunity for testis-sparing intervention.

Dynamic contrast-enhanced MRI in the assessment of testicular perfusion in infertile men with clinical varicocele

BACKGROUND

Varicocele represents the most common correctable cause of male infertility. The presence of non-invasive imaging parameters providing evidence as to which patients with varicocele are at risk for infertility would be important.

PURPOSE

To explore the role of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) using semi-quantitative parameters in the assessment of testicular perfusion in infertile men with clinical varicocele.

MATERIAL AND METHODS

The study cohort included 11 infertile men with clinical varicocele and six controls, with prior paternity. Subtraction DCE-MRI was performed after gadolinium administration, using a three-dimensional fast field-echo sequence. Time-signal intensity curves were created and semi-quantitative parameters were calculated. The independent samples t-test was used to compare basic T1 perfusion parameters between infertile testes with clinical varicocele and normal testes. Logistic regression analysis was performed to assess the most significant predictor of the diagnosis of clinical varicocele.

RESULTS

Both testes with clinical varicocele and normal testes enhanced moderately and homogeneously, with a linear increase of enhancement throughout the examination. Higher mean values of maximum enhancement (P = 0.026), maximum relative enhancement (P = 0.024), and wash-in rate (P = 0.013) were detected in the testes of infertile men with clinical varicocele, compared to the normal population. The wash-in rate proved the most significant predictor of the diagnosis of clinical varicocele (P = 0.013).

CONCLUSION

DCE-MRI may provide a valuable insight into the testicular perfusion of infertile men with clinical varicocele. The wash-in rate proved a strong and independent predictor of the diagnosis of clinical varicocele.

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.

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.

Complete testicular infarction secondary to epididymoorchitis and pyocele

Epididymoorchitis is a relatively common urologic condition involving the scrotum which presents with unilateral pain and swelling. It is typically treated with antibiotics but can progress to complications such as scrotal pyocele. Global testicular infarction is an exceedingly rare but devastating complication of epididymoorchitis. Grey scale and color Doppler ultrasound demonstrate testicular hypovascularity with subsequent hypoechoic changes of the testicular parenchyma. Scrotal MRI shows T2 hyperintense changes through the testicle with nonenhancement of the testicular parenchyma post contrast, consistent with infarction. The cause of global infarction in epididymitis is uncertain but may be due to mixed arterial and venous insufficiency. This case illustrates a 41-year-old male that developed acute left testicular pain. Initial ultrasound showed an enlarged left testicle with hyperemia. The patient's symptoms progressed and a scrotal MRI demonstrated a lack of left testicular enhancement consistent with global infarction, as well as an adjacent pyocele.

A Systematic Review of Testicle Survival Time After a Torsion Event

BACKGROUND

The time window for possible salvage and survival of a torsed testicle is commonly thought to be 6 to 8 hours. However, survival of torsed testicles with or without subsequent atrophy is known to occur outside that critical time window. In this article, we performed a systematic review of the English literature to provide a more accurate understanding of reported time frames of testicle survival after a torsion event.

OBJECTIVES

The primary research question was to determine the relationship between time to treatment and the rate of survival for testicles of male patients presenting with testicular torsion (TT).

METHODS

A systematic review of the literature was performed and structured according to PRISMA guidelines. An exhaustive library search was performed after search strategies were developed for multiple databases that included PubMed, Cochrane library, Ovid MEDLINE, Web of Science, and ProQuest Theses and Dissertations. Two different searches were developed including "testicular torsion" and TT with the search term "time" added. Articles specifically reporting TT case series, testicle outcomes, and time to surgical or manual treatment were selected for review. In addition to and preceding the systematic review, an exhaustive manual search of the literature was also performed by the authors. As a result of these searches, a total of 30 studies with data considered relevant to the research question were included. The information extracted from the articles was tabulated with regard to time intervals to treatment and survival outcome.

RESULTS

The systematic review process and protocol are reported in this article. A total of 30 studies were found that reported case series of TT patients and their outcomes as well as time to treatment reported in useful time frames. From these reports, a total of 2116 TT patients were culled, and their outcomes and time to treatment are reported. Because the time to treatment was reported variously in different case series, the 3 most common formats for reporting time to treatment and outcome were used. When overlap between the tables existed, the data were tallied and reported cumulatively. When reported in 6-hour intervals (1,283 patients), survival at 0 to 6 hours was 97.2%; 7 to 12 hours, 79.3%; 13 to 18 hours, 61.3%; 19 to 24 hours, 42.5%; 25 to 48 hours, 24.4%; and greater than 48 hours, 7.4%. Moreover, we reported cumulative survival data based on reporting for all 3 groups of patients. Testicular salvage in the first 12 hours is 90.4%, from 13 to 24 hours survival is 54.0%, and beyond 24 hours survival is 18.1%. Testicle survival after TT was significant beyond the commonly held 6 to 8 hour time frame and even after more than 24 hours of ischemia.

CONCLUSIONS

Survival of the testicle irrespective of subsequent atrophy, decreased spermatogenesis or impaired endocrine function after TT can be much longer than the 6 to 8 hours that is commonly taught. Our systematic review of the literature demonstrates that survival percentages are significant even past 24 hours of torsion. This information should encourage aggressive management of patients presenting with TT pain that has been ongoing for many hours.

Imaging Modalities in Genitourinary Emergencies

Emergency physicians rely on a multitude of different imaging modalities in the diagnosis of genitourinary emergencies. There are many considerations to be taken into account when deciding which imaging modality should be used first, as oftentimes several diagnostic tools can be used for the same pathologic condition. These factors include radiation exposure, sensitivity, specificity, age of patient, availability of resources, cost, and timeliness of completion. In this review, the strengths and weaknesses of different imaging tools in the evaluation of genitourinary emergencies are discussed.

The split sign: The MRI equivalent of the bell clapper deformity

METHODS:

The cases of eight patients who underwent MRI and surgery for acute scrotum between January 2010 and January 2017 were evaluated. We recorded whether hyperintense fluid on T₂ weighted images existed between the posterior aspect of the epididymis and the scrotal wall ("split sign") and investigated if it correlated with BCD in surgical findings.

RESULTS:

In one patient without hydrocele, readers were unable to evaluate the anatomy of the tunica vaginalis. Among seven patients with hydrocele, five had the split sign and all were surgically confirmed as BCD. In two patients with hydrocele but no split sign, one had normal scrotal anatomy and the other had a BCD with a necrotic testis adherent to the scrotal wall.

CONCLUSION:

The split sign on MRI corresponded well to the lack of fixation of the epididymis to the scrotal wall and detected BCD with high sensitivity (5/6).

ADVANCES IN KNOWLEDGE:

A hyperintense area on T₂ weighted image between the posterior aspect of the epididymis and scrotal wall ("split sign") is a useful MRI finding for diagnosing BCD.

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.

Potential role of imaging in assessing harmful effects on spermatogenesis in adult testes with varicocele

Varicocele is characterized by an abnormal dilatation and retrograde blood flow in the spermatic veins. Varicocele is the leading correctable cause of male infertility. Although it is highly prevalent in infertile men, it is also observed in individuals with normal fertility. Determining which men are negatively affected by varicocele would enable clinicians to better select those men who will benefit from treatment. To assess the functional status of the testes in men with varicocele, color Doppler sonographic parameters were evaluated. Testicular arterial blood flow was significantly reduced in men with varicocele, reflecting an impairment of spermatogenesis. An improvement in the testicular blood supply was found after varicocelectomy on spectral Doppler analysis. Testicular contrast harmonic imaging and elastography might improve our knowledge about the influence of varicocele on intratesticular microcirculation and tissue stiffness, respectively, providing possible information on the early damage of testicular structure by varicocele. Magnetic resonance imaging (MRI), with measurement of apparent diffusion coefficient has been used to assess the degree of testicular dysfunction and to evaluate the effectiveness of varicocele repair. Large prospective studies are needed to validate the possible role of functional sonography and MRI in the assessment of early defects of spermatogenesis in testes with varicocele.

Factitious Disorder Presenting with Attempted Simulation of Fournier's Gangrene

Fournier's gangrene is a severe polymicrobial necrotizing fasciitis of the perineal, genital, or perianal regions. The classic presentation is severe pain and swelling with systemic signs. Crepitus and cutaneous necrosis are often seen. Characteristic CT findings include subcutaneous gas and inflammatory stranding. Unless treated aggressively, patients can rapidly become septic and die. Factitious Disorder is the falsification of one's own of medical or psychological signs and symptoms. Many deceptive methods have been described, from falsely reporting physical or psychological symptoms, to manipulating lab tests, or even injecting or ingesting foreign substances in order to induce illness. We present a case of a 35-year-old man with factitious disorder who attempted to simulate Fournier's gangrene by injecting his scrotum with air and fluid. We will review the clinical presentation and diagnosis of Factitious Disorder, as well as Fournier's gangrene.

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.

Torsion of Undescended Third Testis, as Rare Cause of Painful Inguinal Mass

Twenty years old young was referred to our department due to painful inguinal mass. The mass was diagnosed as torsion of third testis which was treated by orchiectomy. Polyorchidism is a rare entity with increased risk for malignancy and torsion.

Torsion of spermatic cord in children: a review

The current opinion on spermatic cord torsion is discussed in this review, with special attention to natural history, value of diagnostic tools, evidence for surgical management, outcome and management of atypical forms of torsion.

Torsion of a seminoma in an intrascrotal testis: A case report and review of the literature

An intrascrotal testicular torsion with malignant testicular tumour is extremely rare. We report a case of a 26-year-old male who was diagnosed with testicular torsion by magnetic resonance imaging and with testicular seminoma after orchiectomy. Through this case, we found that if the possibility of testicular torsion remains during the diagnosis of acute scrotum cases, additional examination adding to colour Doppler sonography should be performed. Furthermore, we should be aware of the possibility of testicular tumours during the diagnosis and treatment of acute scrotums. If the affected testis is preserved in the treatment of testicular torsion, a postoperative examination by ultrasound and/or tumour markers for the remaining testis is essential to confirm the absence of testicular tumour.

Dynamic contrast-enhanced subtraction MRI for characterizing intratesticular mass lesions

OBJECTIVE

The objective of our study was to analyze the enhancement patterns of various intratesticular mass lesions at dynamic contrast-enhanced subtraction MRI and assess the value of the technique in distinguishing between benign and malignant lesions.

MATERIALS AND METHODS

We retrospectively evaluated the records and images of 44 consecutive men (11 benign and 16 malignant intratesticular lesions) who presented to the department of urology with a variety of clinical symptoms and were referred for imaging. Dynamic contrast-enhanced subtraction MRI was performed using a 3D fast-field echo sequence after the administration of paramagnetic contrast medium. Patients were divided into three groups according to the final diagnosis: benign intratesticular lesions, malignant intratesticular lesions, and normal testes. The patterns of contrast enhancement of both the normal testes and the intratesticular lesions were evaluated. Time-signal intensity plots were created and classified according to shape: Type I presented a linear increase of contrast enhancement throughout the examination, type II showed an initial upstroke followed by either a plateau or a gradual increase in the late contrast-enhanced phase, and type III presented an initial upstroke followed by gradual washout of the contrast medium. The relative percentages of peak height, maximum time, and mean slope were also calculated.

RESULTS

Normal testes enhanced homogeneously with a type I curve. Most benign intratesticular lesions showed inhomogeneous or homogeneous contrast enhancement and a type II curve. Testicular carcinomas showed heterogeneous contrast enhancement with a type III curve. The relative percentages of maximum time to peak proved the most important discriminating factor in differentiating malignant from benign intratesticular masses (p < 0.001).

CONCLUSION

Dynamic contrast-enhanced MRI may be used to distinguish between benign and malignant intratesticular mass lesions.

Triorchidism with torsion

Polyorchidism is a rare anomaly; triorchidism is the commonest type and is frequently associated with cryptorchidism, inguinal hernia, and testicular torsion. It is also reported as an increased risk of testicular malignancy. We report a case of 72-year-old man with left supernumerary testes in the left hemiscrotum. He presented with pain in his left hemiscrotum of short duration. Physical examination revealed tender hemiscrotum. Both ultrasound and MRI examinations revealed polyorchidism. One of the testes in the left hemiscrotum revealed features of torsion and hemorrhagic necrosis. Polyorchidism is a rare entity. In most cases, sonography alone is diagnostic of polyorchidism. Magnetic resonance imaging may provide additional information in complicated cases of polyorchidism.

Magnetic Resonance Imaging of Acute Scrotum

Background and Aims:

The aim of the pilot study was to evaluate the feasibility of dynamic contrast enhanced (CE)-magnetic resonance imaging (MRI) in the detection of testicular ischemia and its ability to differentiate testicle torsion from other causes of acute scrotum.

Material and Methods:

Seventeen boys or young men with an acute scrotum were included in the prospective study during the time period from October 2001 to December 2005. The median age of the patients was 16,4 (7–44) years. The duration of the symptoms preceding the MRI study varied from six hours to 30 days. The study protocol included physical examination by a surgeon, laboratory tests and Doppler ultrasound (DUS) and finally testicles were imaged by using a 1,5 T MRI scanner; T1-weighted and diffusion weighted images were produced. The gadolinium uptake, reported as the region of interest (ROI) perfusion values and presented as curves, was compared between the affected and contralateral testicle. In testicles with normal blood circulation the ROI values increased during the imaging time. Nine patients were operated on, because the spermatic cord torsion could not be excluded by clinical or DUS findings.

Results and Conclusions:

All the normal testicles gave increasing ROI values meanwhile all three testicles with torsion gave constantly low values referring to no perfusion. Other causes of acute scrotum, such as epididymitis and torsion of testicular appendage seemed to be related with normal perfusion. Dynamic CE-MRI seems to show reliably ischemia of testicle and thus it may be helpful in selecting patients with acute scrotum for urgent operation.