Diagnostic ultrasound ( PDFDrive )

CHAPTER 9 The Kidney and Urinary Tract 365
tuberous sclerosis (Fig. 9.78). Periodic CT screening is recommended
to assess for AML growth and tumor development.
TRAUMA
Renal Injuries
Traumatic injury to the kidney may be blunt or penetrating.
Most forms of blunt trauma to the kidney are relatively minor
and heal without treatment. Penetrating injuries are usually the
result of gunshot or stab wounds. Kidneys with cysts, tumors,
and hydronephrosis are more prone to injury. Renal injuries are
classiied into the following four categories 264 :
I: Minor injury (75%-85%): contusions, subcapsular hematoma,
small cortical infarct and lacerations that do not extend into
the collecting system
II: Major injury (10%): renal lacerations that extend into the
collecting system and segmental renal infarct
III: Catastrophic injury (5%): vascular pedicle injury and shattered
kidney
IV: Uteropelvic junction avulsion
Category I lesions are treated conservatively, whereas category
III and IV lesions require urgent surgery. Category II
lesions are treated conservatively or surgically depending on
severity. 264,265
CT is regarded as the premier imaging modality for the
evaluation of suspected renal trauma. 264 Because renal trauma
is frequently accompanied by injuries to other organs, CT has
the advantage of multiorgan imaging. heoretically, sonography
has the capability of evaluating traumatized kidneys; in reality,
technical limitations usually hinder an adequate examination.
Sonography does not provide information regarding renal function
and is probably best used in the follow-up of patients with known
renal parenchymal trauma. Renal hematomas may be hypoechoic,
hyperechoic, or heterogeneous. Lacerations are seen as linear
defects that may extend through the kidney if a fracture is present
(Fig. 9.79). Associated perirenal collections consisting of blood
and urine will be present if the kidney is fractured. Subcapsular
hemorrhage can be seen as a perirenal luid collection that lattens
the underlying renal contour (Fig. 9.80). A shattered kidney
consists of multiple fragments of disorganized tissue with associated
hemorrhage and urine collection in the renal bed. Color
A
B
C
FIG. 9.78 Tuberous Sclerosis With Multiple Angiomyolipomas.
(A) Sagittal and (B) transverse sonograms demonstrate
multiple well-deined echogenic tumors throughout the kidney.
(C) Corresponding noncontrast-enhanced CT examination shows
multiple fat attenuation renal lesions.