This document provides an overview of scrotal anatomy and ultrasound technique for examining the scrotum. It describes the normal ultrasound appearance of the testes, epididymis, vas deferens and surrounding structures. Common benign pathologies are discussed such as hydrocele, hematocele, epididymitis, orchitis and varicocele. Characteristic ultrasound findings for traumatic conditions like testicular torsion and infectious processes like abscess are also outlined. The document serves as a reference for evaluating scrotal ultrasound examinations.

1. Scrotal Ultrasound
Tanya Nolan

2. 2
Scrotal Anatomy
or Globus Major
Or Globus Minor
Covers testes
Tunica Vaginalis
Lines inner walls of
scrotum
Fused tubules that form efferent ducts
Thickened portion of tunica albuginea
(multiple septa)

3. 3
Dartos Muscle and Raphe

4. 4
Prostate
Seminal Vesicles:
Produce fluid rich in fructose
(energy source for sperm
motility after ejaculation)
Prostate Gland:
secretes a thick alkaline
substance that constitutes the
largest part of seminal fluid.
Alkalinity protects sperm from
acid present in the male urethra
and female vagina.

5. 5
Vascular Supply
• ARTERIES
o Testicular Arteries
• Capsular Arteries
o Centripedal arteries
o Transmediastinal / Transtesticular Artery
o Cremasteric and Deferential Arteries
o Pudendal Artery
• VEINS
o Pampiniform plexus
o Right Testicular Vein: drains into IVC
o Left Testicular Vein: joins the left renal
vein
o Deferential Vein
o Cremasteric Vein

6. 6
Epididymis
• Head
o Superior to the upper pole of the
testis
o Contains 10-15 efferent ductules from
the rete testes
• Body, Tail
o Efferent ductules converge to form
Ductus Epididymis and becomes
the Vas Deferens which joins the
duct of the seminal vesicles and
forms the Ejaculatory duct that
empties into the Urethra
• Postvasectomy Changes
o 40% enlargement, inhomogeneity,
spermatoceles, dilation of rete testis, and
sperm granulomas

7. 7
Spermatic Cord
• Extends from the scrotum, through the inguinal canal
and internal inguinal rings, to the pelvis
o Vas Deferens
o Testicular Arteries
o Venous Pampiniform Plexus
o Lymphatics
o Autonomic Nerves
o Fiber of the Cremaster

8. 8
Function and Physiology
• Spermatogenesis
o Testicles
• Produce sperm in seminiferous tubules
o Epididymis
• Serves as a duct through which sperm pass
• Stores small quantities of sperm
• Secretes a small part of the seminal fluid (Semen)
• Secretion of Hormones
o Testosterone
• Secreted by Leydig cells
• Androgen or masculinizing hormone

9. 9
Sperm Pathway
• Seminiferous Tubules
o Produce Sperm
• Tubuli Recti
• Rete Testes
• Efferent Ducts
o Connect testis to epididymis
• Vas Deferens
o Connect epididymis to the ejaculatory duct
• Ejaculatory Duct
o Seminal Vesicle ducts join Vas Deferens on each side to form
the Ejaculatory Duct
• Urethra
o Path by which spermatozoa and urine pass.

10. 10
Songraphic Technique
• Transducer
o High frequency (10-14 MHz) Linear
o Lower frequency may be considered
when wall edema and skin thickening
is present.
o Trapezoid, virtual convex, and
panoramic views may be used in
cases of hydroceles, hematomas, or
swelling.
• Patient Position
o Supine with legs slightly apart and
support placed underneath scrotum.
o Penis and upper thighs are draped
and positioned away from scrotum.

11. 11
Sonographic Technique
• Right and left testis and epididymis are
examined separately in both sagittal
and transverse planes
• Transverse plane images include
superior, middle, and inferior scrotum.
o Measurement is obtained at widest diameter (2-4 cm
in width)
o Compare echogenicity and scrotal skin thickness
o Color Flow Doppler
• Sagittal images include medial and
lateral borders of scrotum.
• Length and AP measurements are obtained at
longest axis. (Length 3-5 cm & 3 cm in AP)
• If patient has a lump/nodule. Have
patient trap it between fingers and then
scan the nodule.
Rete
Testis

12. 12
Normal Testes & Raphe
• An image should be taken demonstrating the
raphe and comparing size, echogenicity, and
texture of each testicle.

13. 13
Color Doppler
• Upper frequency range improves
sensitivity to slow flow.
• Enhance visibility of perfusion
o Gain
o Scale / Pulse Repetition Frequency (PRF)
o Wall Filter
o Line Density
o Threshold
o Packet Size
o Color box / Region of Interest
• Normal Spectral Doppler
o Low resistance waveform in intra-
testicular arteries. (A low-resistance
waveform demonstrates forward
flow during both systole and
diastole.)

14. 14
Indication for
Sonographic Examination
• Painful scrotum
• Scrotal trauma
• Enlargement
• Palpable Mass
• Search for undescended testicle(s)
• Follow-up for patients with a previous orchiectomy
or recent tumor
• Trauma
• Male infertility

15. 15
Pathology
Benign Conditions

16. 16
Scrotal Trauma
• Rupture of the testis is a surgical emergency.
• If surgery is performed within 72 hours after injury, 90% of testes can be
saved. After 72 hours, only 45% can be saved.
• Clinical Findings
o Pain
o Swelling
• Sonographic Findings
o Focal alteration of testicular parenchymal pattern; irregular contour
o Interruption of the tunica albuginea
o Scrotal wall thickening
o Hematocele
o Blood flow disruption across the surface of the testis

17. 17
Hydrocele
• Abnormal accumulation of fluid
in the tunica vaginalis
o Clinical Findings
• Congenital or idiopathic
• Usually due to epididymitis
• Associated with orchitis, spermatic
cord torsion, and trauma
o Sonographic Findings
• Located around the anterolateral
aspect of the testis
• Anechoic or low-level echoes.

18. 18
Hydrocele and Testicular Appendix
The appendix testis is attached to the upper pole
of the testis between the epididymis and testis.

19. 19
Hematocele
• Blood in scrotal sac
• Sonographic Indications
o Acute hematocele is
echogenic with many visible
echoes that can float or move
in real time.
o Aged hematoceles become
more complex and show low
level echoes. They may also
develop a fluid-fluid level or
septations.
o Absent of blood flow

20. 20
Pyocele
• Pus in scrotal sac
o Contains internal septations, loculations, & debris
o Increased vascular perfussion

21. 21
Epididymitis
• Inflammation of epididymis
• Most common cause of acute scrotal pain
• Clinical Findings
o Fever
o Dysuria with possible urethral
discharge
• Sonographic Findings
o Enlarged epididymis
o Thickened scrotal skin
o Decreased echogenicity with
course echo pattern
o Associated with hydrocele
o Increased Doppler flow

22. 22
Orchitis
• Inflammation of the testis;
Infection may be focal or
diffuse
• Enlarged testis
o Severely swollen testis may lead
to testicular infarction.
• Decreased high resistance,
absent blood flow, or Doppler
waveforms demonstrating
reverse diastolic flow is
indicative of testicular
infarction.
• Sonographic Findings
o Affected areas appear hypoechoic

23. Orchitis
6 months after diagnosis
o testicular atrophy
o skin thickness
• Normal skin wall thickness is 2-8
mm thick

24. Epidiymo-
orchitis
• A. Swelling and
Edema
• B. Hyperemic
Perfusion
• C. High
Resistance
Blood Flow

25. Abscess
• Most commonly caused by
untreated epidiymo-orchitis
• Clinical Findings
o Fever
o Scrotal Pain
o Swelling
• Sonographic Findings
o Anechoic or complex mass
o Increased blood flow around
mass periphery
o No blood flow in mass
o Air within the space indicated
abscess

26. Spermatic
Cord
Torsion
• Spermatic Cord becomes twisted and
cuts off blood supply
• Medical Emergency
o Surgery within 5-6 hours onset of pain (80-
100% testes salvaged); 6-12 hours onset of
pain (70% testes salvaged); after 12 hours
onset of pain (20% testes salvaged)
• The degree or number of twists also affects
testicular salvage
• Acute Symptoms
o Scrotal pain and swelling
o Nausea and vomiting
o Sonographic Findings
• Enlarged testicle
• Enlarged epididymal head
• Decreased echogenicity
• Chronic
o Sonographic Findings
• Small heterogeneous testicle
• Scrotal wall thickening
• Possible hydrocele
• No arterial flow
• Partial Torsion
o Sonographic Findings
• Reduced flow with possilbe increased flow in
the peritesticular soft tissue
• Must make comparison to contralateral side.

27. Spermatic Cord
Torsion
A. L testicle enlarged and
heterogenous
B. Mixed echopattern
caused by hemorrhage,
necrosis, & vascular
congestion (torsion > 24
hours)
C. Absence of detectable
Color signal
B
B

28. Spermatoceles & Epididymal Cysts
Spermatocele
• Cyst containing nonviable sperm and
proteinaceous fluid.
o Always Located in Epididymal Head
o More common following vasectomy
Epididymal Cyst
• Cyst containing serous fluid
o Found anywhere within the epididymis
Sonographic Findings
o Palpable
o Clear, Simple, or Multilocular
o Thin Walled
o Posterior Acoustic Enhancement

29. Varicocele • Enlargement of Veins
of Spermatic Cord
o Most common cause of
infertility
o Majority occur on the left
side due to venous drainage
(L renal vein)
o Large, right-sided varicoceles
may be associated with renal
tumor

30. Varicocele
• Sonographic Findings
o Dilated Veins: More than 2mm in diameter
• Valsalva maneuver or having patient stand will increase venous
pressure and increase vessel diameter.
• Reversal Flow occurs when intra-abdominal pressure increases

31. Intratesticular Cysts and Tubular
Ectasia of the Rete Testis
• Intratesticular Cysts
o More common in men over 40
o Associated with spermatoceles
o Single, multiple, variable size
• Tubular Ectasia of the Rete
Testis
o Dilated tubules of Rete Testis
o Associated with spermatoceles,
epididymal or testicular cysts, or
other epididymal obstruction
o Has the appearance of
intratesticular varicocele but has
NO FLOW

32. Epidermoid Cyst
• Rare benign lesion of testis
o Well Circumscribed
o Hypoechoic
o Lamellated
o Little Flow

33. Scrotal Hernia
• Bowel, omentum, or other
structures herniated into
the scrotum
• Sonographic Findings
o Peristalsis during real-time
o Fluid filled bowel loops easily
recognizable

34. Sperm Granuloma
• Chronic inflammatory
reaction to extravasation
of spermatazoa
o Frequently seen in patients
with vasectomy
o Located anywhere within
epididymis or vas deferens
o Sonographic Findings
• Well defined solid mass
• Hypoechoic or isoechoic
• Increased flow with color
Doppler when inflammation
is present

35. Microlithiasis
• Tiny calcifications < 3mm
within testis
o Bilateral
o Associated with testicular
malignancy and cryptorchidism,
Klinefelter’s syndrome, infertility,
varicoceles, testicular atrophy, and
male pseudohermaphroditism
• Sonographic Finding
o Multiple bright non-shadowing
foci scattered through testis

36. Adenomatoid Tumor
• Most common extratesticular tumor
• Clinical Findings
o Generally asymptomatic
o Painless
o Small, slow growing
o Commonly in 5th decade
• Sonographic Findings
o Well circumscribed, solid
o Unilateral (usually left)
o Variable echogenicity
o Associated with hydrocele

37. Pathology
Malignant Conditions
Approximately 95% of all testicular neoplasms are
malignant!

38. Testicular Cancer
• Clinical Findings
o Painless; vague discomfort
o Unilateral enlargement
• Types
o Germ Cell Tumors
• Associated with elevated human chorionic gonadotropin and
alphafetoprotien
o Seminoma
o Embyonal carcinoma
o Teratoma
o Choriocarcinoma
o Stromal Cell Tumors
o Leydig cell
o Sertoli
o Granulose
o Theca cell
o Metastasis
o Lymphoma and Leukemia

39. Seminoma
• Most common germ cell
tumor
• Sonographic Findings
o Hypoechoic lesion
o Smooth border
o Cystic components or
calcification not common

40. Embryonal Carcinoma
o Invasive; aggressive
o Ill defined hypoechoic lesion
o Possible capsular distorion
o Associated hemorrhage, calcification,
o and fibrosis
Teratoma
o Well defined
o Complex Mass
o Possible calcification with
acoustic shadowing
o Usually benign in children

41. Choriocarcinoma
o Mixed appearance depending on dominant cell type
o Typically irregular borders

42. Congenital Anomalies
• Cryptochidism
• Testicular Ectopia
• Anorchia
o Scrotum is empty
• Polyorchidism
o Increased risk of malignancy, cryptorchidism, inguinal
hernia, and torsion
o Duplicated testis are commonly small & efferent
spermatic system is completely absent

43. Cryptochidism
• The testicles do not descend
to their normal position
o 80% are palpable and located in
the inguinal canal region
o 2.5-8 more times more likely to
develop cancer
o 10 times more likely for spermatic
cord torsion
• Surgical Treatment needed
because higher temperature
may prohibit
spermatogenesis and result
in infertility.

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