• 90% - Blunt, 10%-Penetrating
• 10% of pts with significant abdominal trauma.
• When severe, associated with injuries to other
organs in upto 80%.
• When kidney is the only organ damaged,
injury is minor in 98%.
Mechanism of renal trauma
• Blunt trauma: direct blow to the kidney.
• Penetrating trauma: stab or gunshot injury,
• High-velocity deceleration: pedicle injury
(avulsion of renal vessels).
Indications for renal imaging
• Gross hematuria
• Microhematuria with shock( Systolic BP<90 mmHg)
• Microhematuria with
- Flank impact(contusion, haematoma over frank)
• Fracture of lower ribs, transverse processes or thoracolumbar
• Deceleration injury
• Category I- MINOR
-Cortical laceration not extending into a calyx.
• Category II- MAJOR
-Cortical laceration extending into the collecting system(renal
• CategoryIII- CATASTROPHIC
-Renal pedicle injuries
• Category IV
AAST (American Association for the Surgery of Trauma) Classification
• Grade 1
– Nonexpanding subcapsular hematomas
• Grade 2
– Superficial cortical lacerations less than 1 cm in depth without collecting
• Grade 3 –
– Renal lacerations greater than 1 cm in depth that do not involve the
• Grade 4
– Renal lacerations extending to the corticomedullary junction or into the
– Injuries involving the main renal artery or vein with contained hemorrhage
• Grade 5
– Shattered kidney
– Renal pedicle avulsion
• Historical interest, largely replaced by cross sectional imaging.
• Quality of IVU in the setting of trauma is likely to be poor;
hypotensive patient minimal or no secretion from both
• Single shot IVU(full length film 15 mins after contrast inj.)in
hemodynamically unstable patients destined for ER
• Provides information regarding:
-presence of functioning contralateral kidney.
-some gross information about the injured kidney.
• Intra-operative IVU in severely injured patients.
• Absence of unilateral excretion:major vascular injury
(usually RA avulsion)
• Soft tissue swelling with loss of psoas outline:
retroperitoneal, perinephric and subcapsular
• Disruption of PCS:extravasation of opacified urine
(70% sensitivity for urine leak)
15 min single shot IVU in a pt with stab injury to back. IVU-normal kidneys
and ureter bilaterally.
easily available, non invasive, high negative predictive
-poor resolution (compared to CT)
-does not provide information about renal function.
-significant trauma may be missed(upto 80%of
parenchymal lesions may be overlooked)
Findings in USG
• Acute parenchymal, subcapsular and
perinephric hematomas - echo poor areas.
• More heterogenous and echogenic with time.
• Disruption of renal parenchyma with capsular
tears and urinomas can be identified
• Doppler-pedicle injuries.
Grade 4 renal injury. Sonogram in an 8-year-old child with posttraumatic renal
infarction shows both kidneys with an avascular area in the lower half of the affected
• Modality of choice, most accurate technique.
• Allows assessment of entire abdomen,
including liver and spleen.
• Arteriovenous phase
• Delayed scan at 10-20 min
- the abdomen and pelvis should be scanned from the
diaphragmatic dome to pubic symphysis with contrast.
• commence scanning 30 sec after the start of an injection of
50-100ml of 300 strength contrast at 2-3 ml/sec, collimation 7
mm, pitch 1.3, reconstruction interval of 7 mm.
CT Findings:Grade I Injuries
• Contusions and/or non expanding subcapsular hematomas.
-accounts for 80% of renal injuries.
-ill-defined or sometimes sharply marginated areas of
reduced enhancement and excretion.
• Sucapsular hematoma:
-crescentic low density area following the convexity of the
outer aspect of the renal cortex
Grade 1 renal injury, contusion-shows ill-defined area of
hypoenhancement in the medial right kidney.
Grade 1 renal injury, subcapsular hematoma-Image shows crescentic high-
density fluid collection around the left kidney with well-defined outer margin
Grade 2&3 Injuries
• Grade2: non expanding perinephric hematomas contained by the
retroperitoneum and superficial cortical lacerations less than 1 cm in
depth not extending into a calyx.
• Grade3: cortical lacerations greater than 1 cm in depth not extending into
• Perinephric hematoma :
-ill-defined, hyperattenuating fluid collection located between the Gerota
fascia and the renal parenchyma
• Renal lacerations :
-jagged or linear parenchymal disruptions that can contain fresh or
clotted blood .
• Both grade 2 and grade 3 renal lacerations :No evidence of urinary
contrast extravasation on delayed CT.
Grade 2 renal trauma-an ill-defined fluid collection in the left perinephric
space andsubcapsular hematoma with deformity of the renal parenchyma.
Grade 2 renal injury-superficial (less than 1 cm deep) renal
parenchymal defect with a large perinephric hematoma
Grade 3 renal laceration, CT-renal parenchymal defect with extension greater than 1
cm deep to near the renal pelvis
Grade 4 Injuries
• A) renal lacerations that extend into the collecting system,
B) injuries to the main renal artery or vein with contained hemorrhage, and
C)segmental infarctions without associated lacerations.
• Renal lacerations with collecting system involvement :
- frequently produce extravasation of urine or contrast agent.
-delayed images allow adequate views of any urinary extravasation
• Renal segmental infarctions: well-delineated, linear or wedge-shaped, often
multifocal and nonenhancing areas that extend through the parenchyma in a
radial or segmental orientation .
Grade 4 renal injury segmental infarction. Shows a segmental area of
nonenhancement in the upper medial left kidney without associated renal laceration.
Grade 4-5 renal injury shows deep lacerations extending into the collecting system of
the right kidney . Extension into the collecting system is confirmed by urinary contrast
extravasation on the delayed image through the kidney in excretory phase.
Grade 5 Injuries
• Shattered or devascularized kidney, UPJ avulsions, and complete
laceration or thrombosis of the main renal artery or vein.
• Shattered kidney: multiple renal fragments.
• Renal artery disruption/avulsion: commonest vascular injury.
-non perfusion of the kidney.
-some preservation of peripheral perfusion due to early take off of the
-traumatic renal artery dissection may be identified on CT.
• Traumatic renal vein thrombosis.
-thrombus may be directly demonstrated in the renal vein.
• UPJ avulsion-contrast extravasation
-total disruption-ureter fails to opacify.
-partial disruption-contrast appears in the ureter.
Grade 5 renal injury. Shattered kidney with renal vein thrombosis (incomplete). CT
scan shows shattered right kidney and renal vein thrombus extending slightly into the
inferior vena cava.
Grade 5 renal injury, devascularization. CECT shows dissection of the origin of
the left renal artery, with no perfusion of the left kidney.
• MRI provides excellent detail of the renal
anatomy but offers no clear advantage over
CT, and is less able to detect extravasation.
• A rare indication for MRI in the renal trauma
setting may be severe contrast allergy.
• <1% of urinary tract trauma
• Mechanism of injury:
-less often upper 1/3rd
-more frequent in children(sufficient flexibilty
to produce hyperflexion injuries)
b) Iatrogenic: gynaecologic Surgery for malignancy.
• Haematuria may be absent in one third of
• Contrast extravasation
• Formation of urinoma
• Ureteric discontinuity
-mild to moderate fullness of the PCS and extravasation at the
site of tear.
- complete tear-ureter fails to opacify below the tear.
-fistulations to other structures.
• Retrograde pyelogram:
-findings as above.
-limited use in acute setting.
• Blunt trauma:
- most common in patients with multi injury trauma
- predisposed by full bladder at the time of trauma.
- pelvic fractures(especially anterior ring) commonly
-7 % symphysis pubis diastasis associated with bladder
• pre-existing bladder wall abormalities &/or excessive
-bladder tumour,cystitis,perivesical inflammation,
BOO,neurogenic bladder,previous radiotherapy.
1 Contusion (incomplete or partial tear of the bladder mucosa,imaging
findings usually normal)
2 Intraperitoneal rupture (contrast material seen around bowel loops
and in the major peritoneal spaces)
3 Interstitial bladder injury(rare, contrast material dissects into bladder
wall but not outside the bladder)
4 Extraperitoneal rupture (contrast seen within the perivesical
space and a variable number of adjacent extraperitoneal
spaces, depending upon the severity of injury)
5 Combined intraperitoneal and extraperitoneal rupture.
-nearly 100% sensitive for detecting rupture, provided that
adequate distention is accomplished and that post voiding
images are obtained.
-require extra radiography in addition to necessary trauma
-not useful in evaluating trauma to other viscera.
• Advantages of CT Cystography
-less time consuming.
-concomitant injury to other viscera(most
importantly the kidneys)
• The absence of free fluid in the abdomen
during the CT is a strong negative predictor of
• Extraperitoneal rupture:
-commonest bladder injury(90% of cases)
-associated anterior pelvic ring fracture in 90% of cases.
-extravasation of contrast into the perivesical space-
- in florid extravasation,contrast may extend
anterosuperiorly along the anterior pelvic and
abdominal wall upto umbilicus,or posteriorly around
the rectum in presacral space.
-associated tear of urogenital diaphragm allowing the
contrast to appear within the perinerum,thigh and
• The extravasated contrast stays close to the bladder and has a sharp
CT cystogram of victim of motor vehicle collision
(A) shows streaky extravasated contrast material around
urinary bladder consistent with extraperitoneal bladder injury.
(B) Coronal reformatted image better demonstrates the site of
injury at the left bladder base
• Intraperitoneal rupture
-contrast extravasates into the peritoneal
cavity and has a more cloudy nebulous
-usually tear is along the dome of bladder
which is the weakest part.
-associated pelvic fractures seen in 75%
• Almost entirely restricted to males unless
there is major pelvic trauma in females.
• Should be suspected-
– Pelvic trauma with hematuria or retention
– Blood at the urethral meatus.
Imaging: Retrograde urethrogram
Male posterior urethral injuries
Bulbar Urethra Contrast
I Contusion or
Ruptured Yes No
• Type II injuries-most common,rupture at the
prostatic apex (prostatomembranous
junction) immediately above the UGD with
sparing of the UGD itself.
• Type III injuries-membranous urethra ruptures
at the membranobulbar junction below the
UGD,which itself is disrupted.
Retrograde urethrogram reveals a type I urethral injury with minimal stretching and
slight luminal irregularity of the posterior urethra. No extravasation of contrast
material is present
Retrograde urethrogram - type II urethral disruption. Extravasation of contrast
material (solid arrow) from the posterior urethra is seen superior to an intact
urogenital diaphragm (dashed arrow).
Retrograde urethrogram - type III urethral injury. Extravasation is located in both the
extraperitoneal pelvis and in the perineum (above and below the urogenital
Anterior urethral trauma
-iatrogenic (attempted catheterisation,
-blunt perineal trauma(straddle injury):bulbar
urethra and corpus spongiosum are
compressed against the inferior aspect of
anterior pelvic ring.
Straddle injury. Retrograde urethrogram shows a type 5 urethral injury with
extravasation of contrast material from the distal bulbous urethra.
• Injury to the testis may occur from
penetrating wounds, direct impact of high-
velocity objects against the testis or
compression of the testis against the pubic
arch and impacting object.
• Ultrasound is the imaging technique of choice
in acute scrotal trauma.
• Intratesticular haematomas are common after
• The ultrasound appearance depends on the
time between occurrence of trauma and
• Acute haematomas are typically isoechoic to
the normal testicular parenchyma and can be
difficult to identify.
• Testicular rupture implies tearing of the tunica
albuginea with extrusion of testicular
parenchyma into the scrotal sac.
• The margins of the testis are poorly defined
and the echogenicity of the testis is
• The use of colour Doppler is essential as
rupture of the tunica albuginea will almost
always be associated with a loss of vascularity
to a portion of or the entire testis.
• Trauma to the testis can also result in dislocation
• Dislocation most commonly results from impact
of the scrotum against the fuel tank in
• Testicular dislocation, typically into the inguinal
canal, may be detected by CT or ultrasound.
• Testicular torsion is preceded by trauma in 5–8%
• Textbook of radiology and imaging David
• Grainger and Allison’s Diagnostic Radiology 6th
• Fundamentals of Diagnostic Radiology Bryant
& Helms 4th
Hinweis der Redaktion
Major renal injury(grade 4 and 5):
- up to 25% of blunt, and in up to 70% of penetrating renal trauma cases.
(more ant location and proximity to rigid spine or iliac crest)
? omit if normal kidneys with no perinephric, retroperitoneal or pelvic fluid.
addition of 400-600 ml of oral contrast (4% diatriazoate) immediately before scan helps in delineating associated
bowel injuries (stomach,duodenum and proximal jejunum).