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Gray-Scale and Power Doppler Sonographic
Appearances of Acute Inflammatory Diseases
of the Scrotum
Victòria Garriga Farriol, MD, Xavier Pruna Comella, MD, Elena Gallardo Agromayor, MD,
Xavier Serres Crèixams, PhD, Ignasi Barber Martinez de la Torre, MD
Department of Radiology, Hospital General de Granollers, University of Barcelona, Avenida Francesc Ribas,
08400 Granollers, Spain
Received 9 June 1999; accepted 13 October 1999
C
ABSTRACT: Purpose. We describe the spectrum of
gray-scale and power Doppler sonographic appearances in inflammatory scrotal diseases.
Methods. Twenty-five patients ranging in age from
3 to 69 years underwent gray-scale and power Doppler sonography with multifrequency transducers of
7–9 MHz or 10–13 MHz. In addition, color Doppler and
power Doppler findings were compared in 7 cases.
Results. In all 5 prepubertal patients, power Doppler imaging demonstrated hyperemia associated with
epididymitis and, in some cases, orchitis. Among the
20 pubertal and adult patients, power Doppler imaging revealed increased vascularity associated with
spermatic cord involvement, epididymitis, orchiepididymitis, or orchitis. Enlargement and heterogeneity
of the epididymis and/or testis were seen in 11 patients, with vas efferens ectasia in 3 patients. Abscess
formation and testicular infarction were easily depicted by power Doppler imaging. In 5 cases total,
hyperemia was the only sonographic finding of inflammation. In the comparison between color and
power Doppler imaging, a subjective increase in the
number and length of vessels was seen with power
Doppler imaging.
Conclusions. Power Doppler imaging is an easy
and fast Doppler modality for evaluating inflammatory conditions of the scrotum and proved especially
useful in cases with no gray-scale sonographic
anomalies, in prepubertal patients, and in patients
with abscesses or ischemic lesions. © 2000 John
Wiley & Sons, Inc. J Clin Ultrasound 28:67–72, 2000.
olor Doppler sonography has become a useful
tool for assessing patients with acute disorders of the scrotum.1,2 However, the value of color
Doppler sonography in evaluating the prepubertal scrotum is less clear.1
The technology for power Doppler imaging has
existed for many years, but the clinical value of
power Doppler imaging has been recognized only
more recently. In power Doppler mode, the integrated power in the Doppler signal, rather than
its mean frequency shift, is displayed as a color
map on the underlying gray-scale image.3,4 The
advantages of power Doppler imaging over color
Doppler imaging are that power Doppler imaging has less angle dependence and no aliasing
artifacts and thus has higher sensitivity for detecting low-velocity blood flow and better edge
definition. In recent studies, power Doppler imaging has been shown to be more sensitive than
color Doppler imaging in the detection of flow in
small testicular vessels.5 Power Doppler imaging’s capabilities may be increased with the use of
a high-frequency transducer, especially in prepubertal patients.1
Our study examines the spectrum of gray-scale
and power Doppler sonographic appearances of
acute inflammatory disorders of the scrotum.
Keywords: epididymitis; orchitis; scrotum; power
Doppler ultrasonography
PATIENTS AND METHODS
Correspondence to: V. Garriga Farriol
© 2000 John Wiley & Sons, Inc.
VOL. 28, NO. 2, FEBRUARY 2000
From September 1997 through December 1998,
gray-scale and power Doppler sonography were
performed prospectively on 25 patients (3–69
years) with a clinical diagnosis of scrotal inflam67
GARRIGA FARRIOL ET AL
matory disease. Patients were assigned to 1 of 2
groups according to age: prepubertal patients (3–
10 years) and pubertal or adult patients (14–69
years). The clinical diagnosis was based on the
clinical history and results of physical examination and urinalysis. The referring physician made
the decision to obtain a sonographic study to
evaluate associated complications or exclude the
possibility of a condition necessitating surgery.
Oral informed consent was obtained from all
adult participants and from the parents of participants who were children.
In all cases, the initial power Doppler sonograms supported the inflammatory nature of the
process. The final diagnosis was established by an
appropriate response to antibiotic therapy in 18
patients. Sonographic follow-up was performed in
7 patients because of persistence of the clinical
symptoms. The final sonographic imaging findings were consistent with inflammation in 6 of
these patients. Only 1 patient, who had a sonographic diagnosis of testicular infarction at the
second examination, underwent surgery.
The sonographic study included gray-scale and
power Doppler evaluation and was obtained using
a Logiq 700 scanner (GE Medical Systems, Milwaukee, WI). All examinations were performed by
1 of 2 radiologists (V. G. F. and X. P. C.) experienced in scrotal sonography. Depending on the
size of the scrotum, the examination was performed with a multifrequency linear-array transducer of 7–9 MHz or 10–13 MHz. Power and
threshold settings were adjusted individually to
optimize detection of low flow. Color gain was increased to just below the noise level. A subjective
comparison between color and power Doppler sonography was also performed in 7 patients (5
adults and 2 prepubertal patients).
To determine whether the vascularity of the
testis, epididymis, scrotal wall, and spermatic
cord was normal or abnormal, the blood flow pattern depicted within each of these structures on
the symptomatic side was compared with that in
the contralateral, asymptomatic scrotum. Abnormal blood flow was defined as a subjective increase or decrease in the number, size, or length
of the visible vessels in the affected structure
compared with the unaffected structure. Comparison of vascularity between the symptomatic
and contralateral, asymptomatic scrotum was
performed in 2 different planes. In cases in which
both sides were inflamed, we compared blood flow
with the vascular patterns previously established
in healthy volunteers. Results are reported by
number of patients.
68
RESULTS
Sonography demonstrated inflammation of the
epididymis in all of the 5 prepubertal patients
evaluated. Three of them had focal inflammation
of the epididymal head (epididymitis), and 2 had
diffuse epididymal and testicular inflammation
(orchiepididymitis). In all prepubertal patients,
power Doppler sonography revealed a significant
increase in vascularity within an epididymis enlarged to varying degrees. Hyperemia associated
with the epididymitis appeared as short vessels
throughout the epididymis (Figure 1). In cases
with associated orchitis, power Doppler sonography revealed multiple pulsating dots within the
testicular parenchyma corresponding to distal
branches of the centripetal and recurrent arteries
as well as prominent capsular arteries. One case
of orchiepididymitis did not show gray-scale
anomalies, and the hyperemic vasculature was
the only finding consistent with inflammation.
The scrotal inflammatory disorders among the
20 adult patients were as follows: isolated inflammation of the spermatic cord in 2 cases, epididymitis in 8 cases, orchiepididymitis in 8 cases, and
isolated orchitis in 2 cases.
Inflammation of the spermatic cord appeared
on gray-scale sonography as an increase in the
caliber of the spermatic cord and hyperechogenicity of the fat surrounding the vascular structures and vas deferens. Power Doppler imaging
revealed the presence of small colored pixels outside of main vascular structures.
Of the 8 adults affected by epididymitis, 6 of
them had diffuse inflammation, 1 had isolated
epididymal head inflammation, and 1 had epididymal tail inflammation. In the patients with diffuse inflammation, power Doppler examination
revealed a pronounced increase of vessels throughout the epididymis (Figure 2); these could be differentiated from the neighboring pampiniform
plexus by their location and caliber. Associated
gray-scale findings of enlargement and heterogeneous echogenicity of the epididymis were demonstrated in 5 adults with epididymitis. Associated vas efferens ectasia was demonstrated in 3
cases as anechoic tubular and confluent structures containing no flow signals on power Doppler
imaging. In 2 patients, abscess formation with peripheral hyperemia was demonstrated by power
Doppler imaging. Two patients had bilateral epididymal involvement; the sonographic findings
were similar for the 2 sides.
Of the 8 adults affected by orchiepididymitis, 2
had no gray-scale sonographic anomalies, with
the only evidence of inflammation being the hyJOURNAL OF CLINICAL ULTRASOUND
INFLAMMATORY SCROTAL DISEASES
FIGURE 1. Left orchiepididymitis in a 4-year-old boy. (Left) Longitudinal power Doppler sonogram of left
scrotum depicts markedly increased flow within an enlarged head and epididymal tail (arrowheads), as well
as slight intratesticular hypervascularity. (Right) Normal epididymal flow pattern is seen in the contralateral,
asymptomatic scrotum.
FIGURE 2. Diffuse epididymitis in an adult. Power Doppler sonograms of the slightly enlarged body (left) and
tail (right) of the epididymis reveal an increase in vascularity (white arrows).
pervascularity on power Doppler imaging. In the
remaining 6 patients, the gray-scale sonographic
examination showed abnormal thickening of the
epididymis with heterogeneous epididymal and
testicular echotextures. Among these patients, 2
testicular abscesses were depicted at the initial
examination. Associated reactive hydrocele and
scrotal skin thickening were seen in 5 patients.
Power Doppler imaging in the patients with orchiepididymitis revealed an increase in the number of intratesticular vessels and in the caliber of
the capsular arteries, as well as obvious epididymal hyperemia. In the cases of testicular abscess,
power Doppler imaging showed a hyperemic halo
surrounding the fluid collection (Figure 3); this
contributed to the diagnosis. The scrotum and
spermatic cord appeared hyperperfused in 3
cases. Follow-up sonography was able to demonstrate a progressive decrease in the number of
VOL. 28, NO. 2, FEBRUARY 2000
FIGURE 3. Orchiepididymitis with focal testicular abscess formation
in an adult. Power Doppler sonogram shows a hypoechoic, ill-defined
intratesticular lesion surrounded by a rim of hyperemia (arrow).
69
GARRIGA FARRIOL ET AL
vessels within the epididymis and testis after antibiotic treatment in 6 cases. Sonographic followup in 1 patient with severe orchiepididymitis and
a scrotal abscess depicted an avascular testis,
which contrasted with the hyperemic epididymis
and scrotum (Figure 4). The suggested diagnosis
of an extensive ischemic lesion correlated with a
testicular infarction found at the pathologic examination after surgery.
In both patients with isolated orchitis, there
were no gray-scale sonographic anomalies, and a
pronounced increase of intratesticular vessels on
power Doppler imaging was the only finding suggesting testicular inflammation. In 1 of these patients, the hyperemia appeared as a dramatic increase in peripheral vascularity corresponding to
prominent capsular vessels within the tunica vasculosa and to emergent centripetal branches (Figure 5). The appearance was similar to a cortical
renal “blush.”
When considering all 25 patients, we found
that gray-scale sonography failed to depict 5 cases
with an underlying inflammatory process. In
these 5 cases, the hyperperfusion demonstrated
by power Doppler imaging was the main finding
suggesting an inflammatory disease.
The comparison between the 2 Doppler modalities, performed in 2 prepubertal patients and 5
adult patients affected by orchiepididymitis,
showed a subjective increase in the number and
length of vessels within both the epididymis and
the testis with the use of power Doppler imaging.
DISCUSSION
Inflammatory conditions of the scrotum represent
the most frequent cause of acute scrotal pain
among the adult population but are less common
in pre-adolescent boys.1 The severity of these disorders may vary from mild scrotal tenderness to
severe febrile illness with abscess formation.2
Gray-scale sonographic evaluation of epididymitis and orchiepididymitis has been widely described; the findings reflect the severity of the disorder but may not prove reliable in establishing a
correct diagnosis.2 An inflamed epididymis will
usually show focal or diffuse enlargement with an
anomalous echotexture. When the infection
spreads to the testis, there may be a heterogeneous echotexture. On occasion, especially in the
very early stages of inflammation, an initial sonographic study may reveal a hyperechoic, thickened spermatic cord. Unfortunately, none of these
findings is specific, and they may not be present
early in the inflammatory process. In our study, 5
70
patients (4 adults and 1 prepubertal patient) had
no gray-scale sonographic anomalies.
The range of color Doppler findings in scrotal
inflammation is wide and depends on the severity
and distribution of inflammation.6 Keener and
colleagues7 have demonstrated the sensitivity of
color Doppler imaging in detecting the normal
adult epididymal vasculature. Therefore, its visualization does not imply epididymitis, and abnormal epididymal perfusion should be considered
only when there is clearly increased flow compared with that in the contralateral, unaffected
epididymis.7 In addition, Horstman et al8 have
described the color Doppler demonstration of hyperemia in inflammatory scrotal diseases.
Power Doppler imaging is more sensitive in detecting low-velocity blood flow than color Doppler
imaging is,5 and the use of a high-frequency
transducer may improve power Doppler imaging’s
capabilities. In our series, blood flow was better
visualized with power Doppler imaging than with
color Doppler imaging in all 7 cases in which such
a comparison was made.
Because the testicular vessels are small in children, the identification of these vessels in the prepubertal testis is generally more difficult than in
the adult testis. Color Doppler sonography demonstrates testicular blood flow as pulsatile foci of
flow without a demonstrable branching pattern.
A quantitative analysis of intratesticular flow in
children by Luker et al5,9 demonstrated a greater
number of vessels within the testicular parenchyma with power Doppler imaging than with
color Doppler imaging. In our study, power Doppler imaging with a multifrequency transducer of
10–13 MHz was able to easily demonstrate the
testicular and/or epididymal hyperemia in the
prepubertal group. The increased vascularity of
the epididymis was a more useful sonographic
finding than were the gray-scale findings in the
prepubertal group. A similar hyperemic response
can be associated with appendicular torsion, but
the sonographic follow-up excluded that possibility.
In the majority of our adult patients, the hyperemia demonstrated with power Doppler imaging was associated with gray-scale sonographic
changes, except in 4 adults. Although Horstman
et al8 previously reported this phenomenon in 91
patients, that study evaluated only color Doppler
sonographic findings. Based on our experience,
we believe that cases with testicular involvement
are particularly prone to misdiagnosis when studied with gray-scale sonography alone because
power Doppler demonstration of hyperemia was
JOURNAL OF CLINICAL ULTRASOUND
INFLAMMATORY SCROTAL DISEASES
FIGURE 4. Testicular infarction caused by severe orchiepididymitis in an adult. Despite appropriate antibiotic
treatment, power Doppler sonogram 1 week after initiation of therapy shows an obvious contrast between the
avascular testis (left) and the increased peripheral flow consistent with testicular infarction (right).
FIGURE 5. Orchitis in an adult. (Left) Gray-scale sonogram shows a grossly normal testicular echotexture.
(Right) Power Doppler sonogram reveals markedly increased peripheral (arrowheads) and central vascularity.
the only evidence of an underlying inflammatory
disorder in some such cases.
Persistence of an inflammatory process because of lack of therapy or undertreatment results in tissue destruction, which may lead to abscess formation.10 Abscesses appear as anechoic
or hypoechoic ill-defined areas that may mimic a
tumor.2 Power Doppler sonographic demonstraVOL. 28, NO. 2, FEBRUARY 2000
tion of increased vascularity around a lesion provides additional evidence of its inflammatory nature. Sonographic re-examination of patients
with scrotal inflammatory diseases after antibiotic therapy may demonstrate progressive resolution and therefore exclude other diagnostic possibilities, such as a malignant or vascular process.
Infarction after epididymitis is probably due to
71
GARRIGA FARRIOL ET AL
2. Herbener TE. Ultrasound in the assessment of the
acute scrotum. J Clin Ultrasound 1996;24:405.
edema compromising venous drainage, which
leads to thrombosis.11 Arterial compression by a
tense hydrocele has been postulated as another
cause of testicular infarction following inflammatory disease.12 Power Doppler imaging is particularly useful in confirming vascular complications
of severe nonresolving epididymitis. Power Doppler imaging’s ability to better evaluate low flow
states may be helpful in differentiating when an
inhomogeneous echopattern is due to orchitis versus testicular ischemia. In our experience, power
Doppler imaging depicted no intratesticular arterial signals in the case of testicular ischemia.
Early recognition of testicular infarction may enable testicular salvage.
Power Doppler imaging was not superior to
color Doppler imaging in that the former did not
diagnose any epididymitis or orchiepididymitis
that eluded diagnosis with color Doppler imaging.
However, power Doppler imaging was easier and
faster to use than color Doppler imaging. In addition, power Doppler imaging increased the level
of diagnostic certainty, especially in cases with no
gray-scale sonographic anomalies, in the prepubertal group, and in cases with vascular complications.
10. Tumeh SS, Benson CB, Richie JP. Acute diseases
of the scrotum. Semin Roentgenol 1991;12:115.
REFERENCES
11. Eisner DJ, Goldman SM, Petronis J, et al. Bilateral
testicular infarction caused by epididymitis. AJR
Am J Roentgenol 1991;157:517.
1. Albrecht T, Lotzof K, Hussain HK, et al. Power
Doppler US of the normal prepubertal testis: does
it live up to its promises? Radiology 1997;203:227.
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3. MacSweeney JE, Cosgrove DO, Areson J. Colour
Doppler energy (power) mode ultrasound. Clin Radiol 1996;51:387.
4. Rubin JM, Bude RO, Carson PL, et al. Power Doppler US: a potentially useful alternative to mean
frequency–based colour Doppler US. Radiology
1994;190:853.
5. Luker GD, Siegel MJ. Scrotal US in pediatric patients: comparison of power and standard color
Doppler US. Radiology 1996;198:381.
6. Fitzgerald SW, Erickson S, DeWire DM, et al.
Color Doppler sonography in the evaluation of the
adult scrotum. J Ultrasound Med 1992;11:543.
7. Keener TS, Winter TC, Nghiem HV, et al. Normal
adult epididymis: evaluation with color Doppler
US. Radiology 1997;202:712.
8. Horstman WG, Middleton WD, Melson GL. Scrotal
inflammatory disease: color Doppler US findings.
Radiology 1991;179:55.
9. Luker GD, Siegel MJ. Color Doppler sonography of
the scrotum in children. AJR Am J Roentgenol
1994;163:649.
12. Kirk D, Gingell JC, Fenely RCL. Infarction of the
testis: a complication of epididymitis. Br J Urol
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