Applied scrotal ultrasound anatomy and pathology:a pictorial review

Transcription

1 Applied scrotal ultrasound anatomy and pathology:a pictorial review Poster No.: C-1166 Congress: ECR 2014 Type: Educational Exhibit Authors: S. Santos Magadán, D. Gómez-Santos, J. García-Yavar, C. del Riego Fernandez-Nespral, L. F. Taborda Ramírez, 4 2 A. Hernando-García, J. Martínez-González, S. Allodi de la Hoz ; Fuenlabrada/ES, (Fuenlabrada)Madrid/ES, 3 4 Fuenlabrada(Madrid)/ES, Fuenlabrada (Madrid)/ES Keywords: Pathology, Acute, Technical aspects, Ultrasound-Spectral Doppler, Ultrasound-Colour Doppler, Ultrasound, Genital / Reproductive system male, Anatomy DOI: /ecr2014/C-1166 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Page 1 of 43

2 Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 2 of 43

3 Learning objectives 1.To identify normal anatomy of the scrotum and its contents. 2.To describe patient positioning, scanning protocol, and technical considerations for an ultrasound examination of the scrotum. 3.To define the role of color and spectral Doppler in scrotal imaging. 4.To review the most important pathology of intra and extratesticular structures. Background Ultrasound is the imaging modality of choice and the first step used on scrotal pathology for examination of the scrotum. Its ability to diagnose the pathogenesis of acute scrotum is incomparable to any other imaging modality. Radiologists play a key role in diagnosing and appropriately guiding management concerning scrotal pathology, specially in case of acute scrotum, so they need to be aware of the normal anatomy features and pathologic conditions. Findings and procedure details 1. Ultrasound normal anatomy SCROTUM: The scrotum is a sac divided in two compartiments by a tendinous septum. Each compartiment contains a testis with its epididymis and spermatic cord Fig. 1 on page 14. Page 3 of 43

4 Fig. 1: A. Anatomy of the scrotum. B. Sagital ilustration of the pelvic space with the scrotum and its anatomic relations. References: Dulce Gómez Santos, Radiology, Hospital Universitario de Fuenlabrada/ ES The layers forming the wall of the scrotum from the surface to the deep planes are seven: the skin, the dartos muscle, subcutaneous cell layer, the external spermatic fascia, cremaster muscle, the internal spermatic fascia and the tunica vaginalis Fig. 2 on page 14. Page 4 of 43

5 Fig. 2: Ultrasound of the layers of the scrotum. The parietal and visceral layers of the tunica vaginalis are separated by the presence of hydrocele. References: Radiology, Hospital Universitario de Fuenlabrada - Fuenlabrada/ES The tunica vaginalis is a serous membrane with two layers : visceral and parietal layers, which are derived from the peritoneum and vaginal processforming a virtual space. The tunica vaginalis surrounds the testis and epididymis except in the back Fig. 3 on page 15. Page 5 of 43

6 Fig. 3: Ilustration of the sagittal anatomy of the testis References: Dulce Gómez Santos, Radiology, Hospital Universitario de Fuenlabrada/ ES - Content of the Scrotum The testicle: testes are two oval and symmetrical glands housed in the pouch called the scrotum. Their function as male gonads is to produce sperm and male sex hormones. The tunica albuginea is a dense fibrous layer that surrounds the testicle. The tunica sends numerous septa from its deep inner face converging on the back of the testicle where folds inward forming an incomplete septum called the mediastinum testis Fig. 4 on page 16. This creates numerous septation lobules ( ) with wedge shape containing the seminiferous tubules where the sperm is formed. The tubules converge in the mediastinum testis to form the rete testis Fig. 5 on page 17. The epididymis: It is a curved structure measuring 6-7 cm, with posterolateral to the testis position Fig. 1 on page 14. The parts of the epididymis are: head, body and tail Fig. Page 6 of 43

7 6 on page 17. Its function is to carry the semen produced in the sperm ducts to the vas deferens. Testicular appendages are embryonic remnants. The most frequent are the testicular and epididymal appendix. The appendix testis (hydatid of Morgagni) is most of the times ovoid and is usually located on the line between the testis and epididymis head Fig. 7 on page 18. The appendix epididymis is similar, usually pediculated and located in the head of the epididymis. Both can calcify. The spermatic cord: consists of the vas deferens, the cremasteric, deferential and testicular artery, pampiniform venous plexus, genitofemoral nerve, lymph vessels and nerves of the testicles. The spermatic duct has its origin in the deep inguinal ring and descends vertically into the scrotum Fig. 1 on page 14. It suspends the testis in the scrotum. Vascularization: The scrotum and its contents are supplied by three arteries: cremasteric, testicular (branch of aorta) and deferential. The venous drainage is performed through the pampiniforme plexus, which is formed by the binding of small testicular veins ascending the spermatic cord. 2. Scanning techniques The first point to consider before an ultrasound scan is the review of previous sonographic studies of the patient to compare. Preparation and positioning of the patient: The patient should be in a supine position. Scrotum rises on a rolled towel or similar device placed between the thighs. Penis lays on patient's abdomen to separate it from the testicles Fig. 8 on page 19 Page 7 of 43

8 Fig. 8: Patient and transducer positioning: Left: transverse scanning, Right: lomgitudinal scanning References: Radiology, Hospital Universitario de Fuenlabrada - Fuenlabrada/ES Equipment: Ultrasound examination of the testicles should be performed with a high frequency linear transducer, as they are very superficial organs. Frequencies between 7 to 14 MHz frequency are recomended. In cases of large hydroceles or when the scrotum is enlarged, low frequency convex probe can be used (3-4 MHz) or functions as the ultrasound panoramic tool if available Fig. 9 on page 20. It is advisable to apply a generous amount of gel. Color and spectral Doppler frequencies used for scrotum are high frequencies (5 to 10 MHz) because they provide higher resolution and greater sensitivity for the detection of slow or weak flows. Planes: The testicles should be evaluated in at least two planes: longitudinal and transverse. The images in the transverse plane should be obtained at the top, middle and bottom of the testicle. The images in the longitudinal plane must be obtained in a central, medial and lateral position. Each testicle should be swept entirely to identify the epididymis and their parts (head, body and tail). Transverse scaning of both testes in the same image must be obtained to compare them evaluating echogenicity, size and Page 8 of 43

9 vascularization of each testicle Fig. 10 on page 21. The epididymis can be evaluated on the posterior aspect of the testicule (longitudinal axis). Echogenicity and measurements: the thickness of scrotal covers should be evaluated comparatively. Normal wall thickness of the scrotum is 2-8mm, depending on cremaster muscle contraction. Both testes and epididymes are slightly hyperechoic in adulthood (middle echogenicity), may be slightly hypoechoic in childhood (low to medium echogenicity). The normal size of the testis in an adult is 3-5 cm long, 2-4 cm wide and about 3 cm in anteroposterior diameter. Normally the epididymis are isoechogenic or slightly hypoechoic compared to the testicles. The head of the epididymis is a pyramid of about 5-12 mm in length in the upper pole of the testis. The body of the epididymis is very narrow (2-4mm). The tail of the epididymis is located near the lower pole of the testis where it becomes the proximal part of the vas deferens. The mediastinum testis is identified as a hyperechoic band of variable thickness and length extending in craniocaudal direction Fig. 4 on page 16. The rete testis can be identified in some patients as a stratified hypoechoic area adjacent to mediastinum testis Fig. 5 on page 17. The tunica albuginea is shown as a thin echogenic line surrounding the testicle. The two layers of the tunica vaginalis define a virtual space. There may be, under normal conditions, a tiny amount of anechoic fluid between the two layers of the tunica vaginalis, near the head of the epididymis. It should not be confused with hydrocele Fig. 10 on page 21. The testicular appendages are usually isoechoic or hypoechoic compare to testicular parenchyma, less frequently cystic. It is easier to identify when there is fluid between the two layers of the tunica vaginalis, as they are usually crushed against the testis and confused with the testicular parenchyma Fig. 7 on page 18. Vascularization: Must be analyzed with color Doppler, and spectral Doppler modes. Should be performed on all ultrasound examinations of the scrotum, specially in cases of acute scrotum. It is essential to conduct a comparative study with double window scanning in which Doppler setup must be identical to analyze and make pictures of each of the two testes and epididymis. Should begin by studying the healthy testicle to adjust parameters on grayscale and color Doppler and keep them throughout the study. If it is not possible to obtain flow with color Doppler in either testicle, you can optimize the image rising up the gain and decreasing the PRF (Pulse Repetition Frequency) to increase sensitivity, or use the power Doppler, but always keeping the same color Dopper settings in both testicles. Extratesticular structures: In a complete scan ultrasonographic assessment of extratesticular structures (spermatic cord, inguinal canal, etc) must be performed. Valsalva maneuvers or standing position may be employed for its evaluation. The spermatic cord is very shallow structure and often difficult to distinguish from surrounding soft tissues. It is located above the head of the epididymis in the sagittal plane Fig. 1 Page 9 of 43

10 on page 14. It can be seen inside the scrotum when hydrocele is present or with the use of color Doppler. 3. Scrotal pathology 3.1 Congenital anomalies Undescended testicles (cryptorchidism): incomplete descent of one or both testicles on their way from the abdomen into the scrotum, the scrotum is empty. They can be located at any line of descent. They are usually located in the inguinal canal Fig. 11 on page 22. Testicular agenesis (anorchia) may be missing one or both testicles. Testicular atrophy: decreased testicular size compared to normal Fig. 12 on page Testicular tumors: - Benign lesions: Testicular cyst: anechogenic rounded lesion with posterior acoustic enhancement (or without acoustic enhancement if small) embedded in the testicular parenchyma. Cyst of the tunica albuginea: extratesticular millimeter cyst between the layers of the tunica. It is recognized as they deform the testicular contour Fig. 13 on page 24. Ectasia of the rete testis. Benign dilatation of the rete testis by partial or complete obstruction of the vas deferens. It is often bilateral and more common in people over 55 years. It is seen as anechogenic multiple small cystic structures around mediastinum testis. Epidermoid tumor: round lesion with "onion-skin pattern" seen as hyperechoic and hypoechoic alternating concentric rings. Microcalcifications or testicular microlithiasis: hyperechoic milimetric foci with posterior acoustic shadowing spread within the testicular parenchyma. The presence of 5 or more microcalcifications on a single ultrasound view is considered abnormal. It has been linked Page 10 of 43

11 to development of testicular germ cell tumors and although there is no scientific evidence that it is a premalignant lesion ultrasound monitoring is recommended Fig. 14 on page 24. Testicular Macrocalcifications: may be due to scarring processes Fig. 15 on page 25. -Malignant tumors: Usually present as a hypoechoic mass with ill-defined borders and internal vascularity, although quite homogeneous in the case of seminomas. They may be multifocal Fig. 16 on page 26. Non-seminomatous tumors may have cystic areas or echogenic foci due to calcification, fibrosis or hemorrhage Fig. 17 on page 27. They are classified as germ cell tumors (seminoma being the most common testicular tumor) and non-germ cell tumors Acute scrotum: Clinically characterized by acute onset of pain accompanied by signs of inflammation and swelling in the scrotum. It is considered a medical emergency. Causes: -Infection: Epididymitis and orquioepididimitis: is the most common cause of testicular pain in adolescents and adults and is characterized by swelling of the epididymis due to infection. Sonographic features: characterized by unilateral increased flow on color Doppler. The epididymis is usually enlarged and hypoechoic or hyperechoic. There may be reactive hydrocele and thickening of the scrotal layers. Usually begins affecting the cauda epididymis and extends to the body and head. The infection can progress to the testis (orquioepididimitis). In cases of orchitis, testis may have heterogeneous echogenicity and there is an increased flow on color Doppler in the affected testicle, when compared with the contralateral Fig. 18 on page 28. -Torsion of the spermatic cord : Testicular torsion results when the testis and epididimys twist within the scrotum so that the spermatic cord with its testicular vessels are also twisted and vascular compromise occurs. It is an surgical emergency due to risk of testicular ischemia if not detorsioned in the first 4-6 hours. Page 11 of 43

12 Sonographic features: On gray scale, there are non specific features on early stages. Alterations in echogenicity are usually detected in cases of advanced torsion, where we can find heterogeneous testicular echogenicity with hypoechoic areas due to congestion, edema and infarction Fig. 19 on page 29 D. Color Doppler and spectral Doppler are key for its diagnosis. The PRF (pulse repetition frequency) and the filter wall must be set low. Initially there is an absence of venous blood flow and subsequently also arterial flow is cut in the affected testicle when compared with the contralateral Fig. 19 on page 29 A. To rule out testicular torsion it is mandatory to asses intratesticular flow in veins and arteries with spectral Doppler Fig. 19 on page 29 B. The spermatic cord mass of torsion is known as "whirlpool sign". It is highly specific of testicular torsion and is manifested as a spiral shaped doughnut, a target or a snail seen with no flow or low flow if intermittent torsion. The whirlpool mass is seen in various locations: just distal to the external ring, above the testis or posterior to the testis, and in the inguinal canal if the testis is undescended. In cases of spontaneous resolution you can see a greatly increased flow due to intratesticular reperfusion (reperfusion phase). Torsion of testicular appendage: Sonographic features: enlarged appendix, with increased peripheral flow at Color Doppler ultrasound. Often, there is a certain amount of reactive hydrocele. After the acute episode appendix shrinks and calcifies Fig. 20 on page 30. The role of ultrasound in these cases is to rule out testicular torsion and orquioepididimitis. -Trauma: It usually occurs as a result of direct trauma. The most important thing to consider is whether there is testicular rupture since it is a surgical emergency. Ultrasound findings of trauma: Hydrocele is manifested as a anechoic collection of liquid between the two layers of the tunica vaginalis Fig. 21 on page 31. It can show millimeter echogenic foci inside. Hematocele (blood in scrotum) is seen as complex cystic collection with internal septa forming compartments Fig. 22 on page 32, Fig. 23 on page 33. Its appearance is very similar to pyocele (infected hydrocele). Hematoma: acute testicular hematoma is hyperechoic and may mimic a testicular mass Fig. 24 on page 33. After 1-2 weeks becomes cystic. Page 12 of 43

13 Testicular rupture is manifested as a discontinuity of the tunica albuginea. There may also be irregular contour and heterogeneous testicular echogenicity with loss of vascularity of testicular parenchyma Fig. 25 on page 34 Testicular fracture: Breaking discontinuity or rupture of testicular parenchyma. Sometimes you can identify a hypoechoic line corresponding to an avascular area in the testicular parenchyma, a finding that may be associated or not to rupture of the tunica albugínea Fig. 26 on page Extratesticular pathology: -Epididymis Epididymal cysts: are common and are usually located on the head of epididymis Fig. 27 on page 36. Spermatocele sperm retention cysts: similar to epididymal cysts with more echogenic content. They are located in the head and may occur after vasectomy. Adenomatoid tumor: It is the most common benign tumor of the epididymis and it is usually located in the tail. The typical appearance is that of a hyperechoic, homogeneous and well-defined nodule Fig. 28 on page 37. Other benign tumors are lipomas, leiomyomas and cystadenomas. Malignant tumors of the epididymis are rare. -Spermatic cord Varicocele is an abnormal dilation of the veins of the pampiniform plexus. They are more common on the left side. Sonographic features: Sinuous anechoic structures in the posterior aspect of the testis. The use of color Doppler mode during Valsalva maneuver is key to diagnosis when a striking increase in the diameter and flow of the affected veins is shown Fig. 29 on page 38. Sometimes it is necessary to explore the patient in standing position to improve visualization of the venous flow increase. Miscellany Page 13 of 43

14 Scrotoliths (scrotal pearls) are free calcifications within the tunica vaginalis, They result of torsioned appendages or inflammatory calcium deposits. They can measure from a few millimeters up to 1 cm Fig. 30 on page 39. Inguinoescrotal hernia is the most common extratesticular mass in the scrotal sac. Normally contains bowel loops or fat. Intestinal hernias are filled with liquid and gas, show peristalsis and increase in size with Valsalva maneuver. They can be located in the inguinal canal or scrotum Fig. 31 on page 40. Images for this section: Fig. 1: A. Anatomy of the scrotum. B. Sagital ilustration of the pelvic space with the scrotum and its anatomic relations. Page 14 of 43

15 Fig. 2: Ultrasound of the layers of the scrotum. The parietal and visceral layers of the tunica vaginalis are separated by the presence of hydrocele. Page 15 of 43

16 Fig. 3: Ilustration of the sagittal anatomy of the testis Page 16 of 43

17 Fig. 4: Transverse scan of the teste. Mediastinum testis (red arrows) Fig. 5: Rete testis (red arrow) Page 17 of 43

18 Fig. 6: Parts of the epididymis: Head (blue arrow) Body (red arrows) Tail (yellow arrow) Page 18 of 43

19 Fig. 7: Testicular appendage (red arrow). Large hydrocele. Page 19 of 43

20 Fig. 8: Patient and transducer positioning: Left: transverse scanning, Right: lomgitudinal scanning Page 20 of 43

21 Fig. 9: Longitudinal scan of the teste (panoramic view). Longitudinal and transverse measures. Page 21 of 43

22 Fig. 10: Comparative testes A) Comparison of both testicles (grayscale) in the same window, to evaluate size and echogenicity. Minimal amount of fluid between the two layers of the tunica vaginalis testis is considered physiological (arrow). Comparative in color Doppler, similar vascularity in both testes. Page 22 of 43

23 Fig. 11: A.Criptorquidia.The testis is in the inguinal canal due to incomplete descent. B.Intrabdominal undescended testicle (red arrow ) below the lower pole of the kidney (blue arrow). C.Note the typical flow of the testis in the Doppler color. Six months later it descended into the inguinal canal.courtesy of Dr. Muro ( Hospital de la Zarzuela). Page 23 of 43

24 Fig. 12: Testicular atrophy. The testis of the image on the left is diminished in size, with no flow and hypoechoic relative to the contralateral testis in the right image Fig. 13: Cyst of the tunica albuginea. Note the testicular deformed contour. Presents a discrete posterior acoustic enhancement typical of cysts Page 24 of 43

25 Fig. 14: Testicular microcalcifications: five or more echogenic foci in the testicular parenchyma. Page 25 of 43

26 Fig. 15: Macrocalcification in testicular parenchyma due to previous trauma. Posterior acoustic shadowing. Page 26 of 43

27 Fig. 16: Multifocal seminoma: heterogeneous (hipoechogenic) intratesticular nodules (arrows). B. Doppler color shows internal vascularity. Page 27 of 43

28 Fig. 17: Malignant testicular tumor (seminoma and carcinoembryonic).poorly defined hypoechoic solid mass that affects part of the testis with large cystic area. Page 28 of 43

29 Fig. 18: Epididymitis: A. Thickening of the scrotal covers on the left compared with the right image. B. Increased vascularity in the head of the epididymis in the left image. Epididymal cyst (right), incidental finding. Page 29 of 43

30 Fig. 19: Testicular torsion: A. Color Doppler US of the testis. Note the absence of intratesticular blood flow in the left testis. B. Spectral Doppler demonstrating intratesticular blood flow. C. Late torsion (more than 24 hours). Thickening of the layers due to swelling and congestion. D. Missed torsion: Heterogeneus echoestructure secundary to vascular congestion, hemorrhage and infarction. Page 30 of 43

31 Fig. 20: Hyperechoic and calcified twisted appendix testis between the head of the epididymis and testis ( red arrow). Page 31 of 43

32 Fig. 21: Large hydrocele. Anechoic collection between the two layers of the tunica vaginalis. Small echogenic foci can be seen inside. Page 32 of 43

33 Fig. 22: Pyocele: Complex collection with septa inside (infected hydrocele). It has the same appearance as a hematocele. Fig. 23: Acute hematocele: Fluid collection with hyperechoic foci in dependent areas. Page 33 of 43

34 Fig. 24: Hematoma. Irregular contour and hyperechoic testicular mass. The traumatic history leads to the diagnosis of hematoma. Page 34 of 43

35 Fig. 25: Testicular rupture. Discontinuity of the tunica albuginea (red arrow). Hematocele. Page 35 of 43

36 Fig. 26: Testicular fracture. A. Hypoechoic line crossing the testicular parenchyma (arrows) and irregularity of contour consistent with fracture. B. Absence of color Doppler signal in the area of the fracture. Hydrocele slightly hyperechoic (hematocele). Page 36 of 43

37 Fig. 27: Longitudinal scan of the testis. Simple cyst in the head of the epididymis Page 37 of 43

38 Fig. 28: Adenomatoid tumor. Hyperechoic, homogeneous and well defined nodule in the tail of the epididymis (red arrow) Page 38 of 43

39 Fig. 29: Varicocele: Longitudinal view of the spermatic cord in which sinuous anechoic structures are identified. Increased flow on color Doppler with Valsalva maneuver. Page 39 of 43

40 Fig. 30: Scrotal pearl. Rounded calcification with posterior acoustic shadowing between the two layers of the tunica vaginalis. Page 40 of 43

41 Fig. 31: Inguinal hernia: heterogeneous content in the inguinal canal that increases with Valsalva maneuver. Page 41 of 43

42 Conclusion The major points of this exhibit are: - Knowledge of scrotal anatomy and pathology ultrasound appearance as well as application of proper US technique is essential for accurate diagnosis of scrotum diseases. - High-frequency transducer sonography combined with pulsed and color Doppler sonography provides the information essential to reach a specific diagnosis in patients with testicular torsion, epididymo-orchitis, and testicular trauma. Personal information References 1.DograV, Gottlieb RH, Oka M, Rubens DJ. Sonography of the scrotum. Radiology 2003;227: Mirochnik B, Bhargava P, Dighe, MK,Kanth N. Ultrasound evaluation of scrotal pathology. Radiol Clin North Am 2012;50: Dogra V, Bhatt S. Acute painful scrotum. Radiol Clin North Am 2004;42: Dogra VS, Gottlieb RH, Rubens DJ, Liao L. Benign intratesticular cystic lesions: US features. Radiographics 2001; 21:S Valentino M, Berlotto M, Ruggirello M, Pavlica P, Barozzi L, Rossi C. Cystic lesions and scrotal fluid collections in adults: Ultrasound findings. J Ultrasound 2011;14: Bhatt S, Dogra VS. Role of US in testicular and scrotal trauma. Radiographics 2008;28: Page 42 of 43

43 7.Woodward PJ, Schwab CM, Seterhenn IA. Extratesticular scrotal masses: radiologicpatologic correlation. Radiographics 2003; 23: Garriga V, Serrano A, Marin A, Medrano S, Roson N, Pruna X. US of the tunica vaginalis testis: anatomic relationships and pathologic conditions. Radiographics 2009;29: Kim W, Rosen MA, Langer JE, Banner MP, Siegelman ES, Ramchandani P. US-MR imaging correlation in pathologic conditions of the scrotum. Radiographics 2007;27: Vijayaraghavan SB. Sonographic differential diagnosis of acute scrotum: real-time whirlpool sign, a key sign of torsion. J Ultrasound Med 2006; 25: Del Cura JL, Pedraza S, Gayete A. Radiología esencial. Tomo 1. Médica Panamericana DL Dambro TJ, Stewart RR, Caroll BA. Escroto. In: Rumack CM, Wilson SR, Charboneau JW. Diagnóstico por ecografía. Tomo 1, Segunda edición. Madrid. Marbán SL. 2004; Robert L, Bree MD. Próstata. In: Rumack CM, Wilson SR, Charboneau JW. Diagnóstico por ecografía. Tomo 1, Segunda edición. Madrid. Marbán SL. 2004; Page 43 of 43