Ultrasound is the initial imaging modality of choice for evaluating acute scrotum. Common causes include epididymitis, orchitis, abscess, testicular torsion, trauma, and Fournier's gangrene. Familiarity with ultrasound appearances is important to differentiate conditions and guide treatment. Testicular torsion and Fournier's gangrene require timely treatment. The testis, epididymis, and vas deferens are evaluated with ultrasound. Color Doppler can identify absent or reduced blood flow in torsion. Epididymitis appears as an enlarged, hypoechoic epididymis with increased vascularity. Orchitis involves both the testis and epididymis with enlargement

1. Imaging in Acute scrotum
Imaging in Acute Scrotum

2. Introduction
• Ultrasound is the initial modality of choice in evaluating
scrotal emergencies.
• Common diseases seen in the emergency department
include epididymitis, orchitis, abscess, testicular torsion,
trauma, Fournier’s.
• Familiarity with the characteristic sonographic features and
common pitfalls and mimickers is essential to differentiate
these conditions and initiate treatment.
• This is particularly important for Fournier’s gangrene, testicular
torsion, and testicular rupture because timely treatment is
crucial to preserving fertility and hormonal activity.

3. Anatomy
• Testis
• Epididymis
• Vas deferens
• Venous plexus
• Testicular artery
• Appendix of epididymis (remnant from embryogenesis)
• Appendix of testis (remnant from embryogenesis)

4. Layers of Scrotum
Skin
Dartos Muscle
Fascia
Pareital layer of tunica albuginea
Visceral layer of tunica albuginea
Testis

5. Anatomy
• Sperm is produced in the
seminiferous tubules (S).
• The seminiferous tubules converge in the
mediastinum testes as a network of
tubules called the rete testes (RT).
• The efferent ductules (curved black arrow)
bridge the testicle and epididymal head (EH),
which leads to the epididymal body (EB) and tail
(ET).
• Sperm exit the scrotum through the vas
deferens (straight black arrow).
• The tunica albuginea (A) surrounds the testicle.
• The tunica vaginalis (arrowhead) has two
layers and also partially surrounds the testicle.
• The testicular (internal spermatic) artery
(white arrow) supplies the testicle.

6. Normal Anatomy
Tunica albuginea –
thin echogenic line
Mediastinum testes –
horizontal echogenic
band

7. Characteristic appearance of testis

8. Systematic approach for a logical D/D
Without Trauma
Short duration of symptoms (<
6 hours)
Long Duration (days to weeks)
Torsion Inflammatory Conditions:
● Epididmo-orchitis
● orchitis
● epididmytis
With Trauma
● Rupture
● Fracture
● Hematoma
Pain
Torsion and Testicular
rupture are medical
emergencies

9. Systematic approach for a logical D/D
Pain
With Visible Swelling
With signs of scrotal wall
Inflammation
Without visible swelling but a palpable
swelling maybe present. Only 10-20%
present with pain.
Without signs of scrotal
wall inflammation
Intra-testicular tumors Extra testicular tumors
● Fournier’s Gangrene ● Strangulated
ilioinguinal hernia
Usually malignant
Intratesticular (usually malignant)
– Seminoma (40-50%)
– Mixed (40%)
– Germ cell tumor
– Teratoma
– Choriocarcinoma
– Metastases (kidney, prostate,
lung, pancreas, bladder, thyroid,
melanoma, GI)
– Non-Germ Cell (Sertoli, Leydig,
Mesenchymal)
Extratesticular (usually beni
– Adenomatoid Tumor of th
Epididymis (30%)
– -omas: Leiomyoma, Fibrom
Lipoma
•Varicocele
•Cyst/Abscess
Fournier’s and
Strangulated
hernia’s are medical
emergencies

10. Testicular torsion - Technical aspects
The Knot:
Knot can be mistaken for an enlarged epididymis
Knot may show shadowing
With practise the side of the torsion (Clock/ Counter clock wise rotation) can be identified
which can help in manual detorsing the testis

11. Testicular torsion - Technical aspects
Colour Doppler
Intratesticular vessels travel in certain vascular planes
Orientation of the probe with respect to these planes will affect the apparent vascularity of the testis.

12. Testicular torsion - Technical aspects
The Cremastric reflux
Can be avoided with a warm gel

13. Testicular Torsion US Features
Grey Scale:
Hyperechoic - Viable irrespective of duration of symptoms.
Hypoechoic or heterogenous - Likely to be non viable.
Doppler:
In most cases - Absent flow, Occasionally there maybe minimal flow
In prolonged duration of a torsion scrotal wall may show hyperemia.
Doppler also helps in documenting a successful manual detorsion maneuvre
Mimicker:
De torsed testis appears hyperemic and sometimes maybe misdiagnosed as orchitis.
NOTE: Though Doppler plays an important role in diagnosing torsion, Some patients may show normal
symmetric flow, hence it is crucial to to combine grey scale and Doppler to come to a diagnosis.

14. Twisted spermatic cord

15. Torsion with absent blood flow

16. Torsion of spermatic cord with decreased
but detectable flow

17. Delayed torsion. Transverse view shows a heterogeneous,
hypoechoic testis with no blood flow. There is increased flow in
the surrounding scrotal wall.

18. Torsion with symmetric blood flow. A, Longitudinal color and pulsed Doppler
views of the normal left testis show readily detectable internal vascularity
and a strong arterial signal with a normal waveform morphology.
B, Longitudinal view of the torsed right testis shows less internal vascularity
on color Doppler, but a symmetric and normal appearing arterial waveform.
Gray-scale findings in this case were consistent with torsion and torsion was
confirmed at surgery.

19. Manual detorsion. A, Longitudinal view of the torsed testis
indicates absence of blood flow. B, Immediately following
manual detorsion there is postischemic hyperemia in the
testis, confirming that the detorsion was successful.

20. Epididimytis
Grey Scale:
Hallmark of epididymitis is enlargement
May or not have decreased echogenicity.
Involvement of the epididymis may be diffuse or focal.
Focal involvement frequently occurs in the tail. Therefore it is important to scan the entire
epididymis in patients with suspected epididymitis.
Color Doppler
hyperemia as increased epididymal vascularity.
Complications:
Advanced epididymitis can obstruct venous outflow and cause testicular ischemia and even
testicular infarction. This should be suspected when there is reduced testicular blood flow on color
Doppler or when there is reversed diastolic blood flow in intratesticular arterial waveforms.
In patients with advanced epididymitis, small abscesses are occasionally seen as avascular,
complex hypoechoic collections in the epididymis..
One pitfall is the enlarged epididymis that occurs following vasectomy. This can be differentiated
from enlargement due to inflammation by noting bilateral involvement and lack of
hyperemia. The enlargement of the epididymis that follows

21. Epididimytis in different patients

22. Orchitis
Orchitis usually occurs with epididymitis.
Isolated orchitis is less common and generally viral in nature (i.e., mumps).
US Features:
Testicular enlargement,
decreased echogenicity,
heterogeneity, and
hypervascularity.
Orchitis is also a cause of a striated testis.

23. Orchitis.. Contd
DD for an enlarged, hypoechoic testis:
Torsion, diffuse lymphoma or leukemia, and diffuse seminoma.
Orchitis is much less frequently focal than is epididymitis. In such cases it can be difficult to
distinguish a hypoechoic hypervascular tumor from focal orchitis .
Clues that make orchitis more likely are pain and tenderness without a palpable mass on physical
examination and the sonographic finding of associated involvement of the epididymis.
Complications:
Testicular abscess if appropriate therapy is not administered.
Scrotal wall abscesses may develop from testicular abscesses or they may arise primarily
within the soft tissues of the scrotum. They may occur at the scrotal–perineal junction and can be
missed if scanning is only done from an anterior scrotal approach.

24. DD for focal hypoechoic lesion with
enlarged testis
Abnormalit
y
Blood
Flow
Physical
Examination
Orchitis Increased Tender
Torsion Decreased Tender
Lymphoma Increased Nontender
Seminoma Increased Nontender

25. Orchitis in different patients. A, Transverse view of both testes shows an
enlarged and hypoechoic left testis. B, Longitudinal view shows patchy
areas of decreased echogenicity. C, Transverse dual power Doppler views
of both testes show enlargement and increased vascularity of the right
testis. D, Transverse color Doppler view of both testes shows increased
vascularity but normal size and echogenicity of the left testis.

26. Focal Orchitis

27. Complicated inguinoscrotal hernia
Hernias in different patients. A, Longitudinal view shows the testis inferiorly (T) and a
hernia sac containing loops of small bowel superiorly. Peristalsis could be seen on real-
time examination. B, Panoramic longitudinal view shows the testis inferiorly (T) and
shadowing, gas-containing loops of bowel superiorly.

28. Fournier’s Gangrene
• US: Punctate echogenic foci within the left testicle,
concerning for gas.
• CT: Gas in the left scrotum, which tracks into the
inguinal canal, retroperitoneum, and along the
left gonadal vein.
• Fournier’s gangrene is a rapid progressive
necrotizing infection involving both the
superficial and deep fascial planes.
• It is a urologic emergency due to the high
mortality.
• Gas within the soft tissues is characteristic, but
it’s absence does not exclude the diagnosis.
• CT is the modality of choice because it may depict
the source of infection and its pathways of
spread.

29. Trauma
Rupture - Disruption of tunica albuginea
Fracture - Tearing of parenchyma +/- disruption of tunica albuginea
Hematocele - Collection of blood within the testis

30. Testicular Rupture
A visible disruption of the tunica albuginea is a definitive finding , but it
is often not detected.
A contour abnormality indicates extrusion of seminiferous tubules
through a disrupted tunica albuginea and is a common and reliable
secondary sign
Heterogeneous areas of increased or decreased echogenicity are
usually present with a disrupted tunica albuginea, but they should not
prompt a diagnosis of rupture unless they are accompanied by a
contour abnormality.

31. Testicular Fracture
Testicular fracture refers to tearing of the parenchyma with or without
disruption of the tunica albuginea.
It may or may not be associated with rupture of the tunica. It appears as a
focal hypoechoic and hypovascular or avascular intratesticular defect.
Intratesticular hematomas are also relatively common in the setting of
trauma

32. Testicular rupture in different patients. A, Longitudinal view shows disruption of the
tunica albuginea in at least two locations (arrows). B, Longitudinal view shows a severe
contour abnormality (arrows) of the testis (T), due to a disruption of the tunica and
extruded seminiferous tubules (S). C, Transverse view shows the testis with a contour
abnormality (arrows) and extruded seminiferous tubules (S). There is a surrounding
hematocele (asterisks). D, Transverse panoramic view shows a large hematocele
(asterisks) and a misshaped left testis (T). E, Transverse view shows a bullet fragment
(arrowhead) within a large hematoma. No recognizable testis is seen. F, Longitudinal
power Doppler view shows heterogeneity of the lower pole with decreased blood flow
to this area.

33. Epididymoorchitis.
d
Clinical History
• Testicular pain for 3 days.
Imaging Findings
• Right testicle with
heterogeneous echotexture and
increased flow.
• Enlarged epididymis with
heterogeneous echotexture
and increased flow.

34. Epididymitis & Epididymal Abscess
Clinical History
• Two weeks of right
testicular swelling.
Imaging Findings
• Enlarged, hyperemic left
epididymis containing a
large cystic structure with
layering echogenic fluid
(abscess).
• Complex left hydrocele.
Teaching Points
• Infection spreads in a
retrograde fashion. The
epididymal tail is involved
before the body and head
and should be carefully
evaluated

35. Diagnosis: Scrotal Abscess &
Nonviable Testis
Clinical History
• Homeless male with history of
grade 1 scrotal trauma with
hematocele who presents a month
later with acute onset of worsening
right testicular pain and swelling.
Imaging Findings
• Complex fluid collection in the
right scrotum.
• Thickening of the right scrotal
soft tissues.
• Asymmetrically smaller right
testicle without flow.
Learning Points
• Orchitis unresponsive to
antibiotics requires surgical
drainage.
• Untreated orchitis can lead to
vascular compromise resulting
in testicular infarction and
atrophy.
Scrotum

36. Leydig Cell Tumor
Clinical History
• 34 year old male with right
testicular pain and swelling.
Imaging Findings
• Focal heterogeneous area in
the testis with vascularity.
• Normal epididymis (not shown).
Learning points
Focal orchitis would present as a
hypoechoic area with or without
peripheral flow, but no central flow.
Orchitis is usually associated with
epididymitis.

37. Embryonal cell tumour
Clinical History
• 26 year‐old male with sudden
onset of 10/10 right testicular
pain for 2 hours with
associated mild erythema and
swelling.
Imaging Findings
• Hypoechoic irregular area with
calcifications and increased
flow.
Teaching Points
• Focal orchitis would not
have calcification or central
flow.

38. Testicular Ruptured
Testis
Clinical History
• Kneed in the scrotum while
playing soccer.
Imaging Findings
• Markedly heterogeneous right testicle
with loss of normal contour,
disruption of tunica albuginea, and
small hypoechoic regions.
• Avascular hypoechoic regions
represent intratesticular hematoma.
• Complex fluid surrounding the
testicle, representing a hematocele.
Teaching Points
• Findings of testicular rupture:
heterogeneous testicular
echotexture, testicular contour
abnormality, or disruption of the
tunica albuginea

39. Testicular Rupture &
Fracture
Clinical History
• 28‐year‐old male who was hit in the right
scrotum with a baseball 24 hours ago.
Imaging Findings
• Enlarged testicle with heterogeneous
echogenicity and an irregular capsule
(testicular rupture).
• More linear hypoechoic area
(testicular fracture).
• Small avascular hypoechoic areas
(intratesticular hematomas).
• Complex fluid surrounding the
testicle (hematocele).
More linear
hypoechoic
area
Intratesticula
r hematoma

40. Devascularized & Ruptured Testicle
Clinical History
• Clipped by a car while
riding a motorcycle.
Imaging Findings
• Markedly
heterogeneous testicle
with avascular areas.
• Loss of normal
testicular contour.
• Disruption of the thin
echogenic tunica albuginea.