A

B

C

D E

Click on Images for Enlarged View

Findings: (A and B) CT scan of the abdomen with oral and intravenous contrast media, obtained immediately after the traumatic insult demonstrates a large, rather poorly-defined focus of relative hypodensity within the left lobe of the liver, consistent with a parenchymal laceration. Periportal tracking of fluid can be noted as hypodensity around the contrast-enhanced left branch of the portal vein.

(C) Axial CT image of the abdomen obtained approximately 40 mm caudal to those in (A) and (B) demonstrates an enlarged, edematous pancreas, without direct evidence for parenchymal disruption or duct laceration. Surrounding the organ is a cuff of hypodensity, consistent with blood and/or extravasated pancreatic juice.

(D and E) Delayed (48-hour) axial CT images of the mid-abdomen illustrate a multifocal laceration-injury to the pancreatic body; these images better define the degree of parenchymal injury than do those from the original study.

Diagnosis:Pancreatic Hepatic Laceration Injuries status post Blunt Abdominal Trauma (MVA)

Discussion: In patients having undergone blunt abdominal trauma, the liver is the most commonly injured of the viscera.1 Traumatic hepatic injuries, characterized primarily as subcapsular hematoma, parenchymal laceration and/or fracture, account for approximately 25% of the sum-total of both isolated and multi-organ injuries sustained following a blow to the abdominal region. Traumatic injuries to the liver are also characterized, in part, by the site of involvement. Isolated lobar injury accounts for approximately 65% of the total of that to the liver; of these, approximately 80% tend to occur in the right lobe, predominantly in its posterior segment. Injury to this region tends to be manifest has a hematoma, described as a well-defined, linear or "simple" lesion. Roughly 20% of isolated hepatic lobar traumatic injuries are confined to the left lobe, divided in approximately equal frequency between its medial and lateral segments. Blunt-traumatic injuries to the left lobe of the liver are typically poorly-defined lacerations displaying a branching or stellate configuration; these are termed "complex" or "intrahepatic burst" lesions.7.

Freshly sustained intrahepatic parenchymal laceration-injuries post-blunt trauma tend to demonstrate isodensity relative to that of uncontrasted liver parenchyma on CT. Following the administration of intravenous contrast medium, however, the lesions become more discernable, becoming hypodense relative to that of the surrounding contrasted hepatic parenchyma. A concomitant finding at imaging is frequently that of relative hypodensity about the contrast-enhanced portal venous structures. This phenomenon is described as "peri-portal venous tracking" of blood or lymphatic fluid.1,4

Injuries to the pancreas are, on the other hand, exceedingly rare, accounting for less than 5% of the total of all abdominal injuries suffered after blunt abdominal trauma.1,2,3 Traumatic injury to the pancreas is often a function of the organ's position in the mid- retroperitoneum, in close proximity to the thoracolumbar spine. Laceration-type injuries to the pancreas usually result from abrupt, forceful compression against the spine, with the vector of force directed against the long-axis of the organ. This scenario is typical in both "automobile seat-belt" and "bicycle handlebar" injuries, described not infrequently.6

Cross--sectional imaging can allow for the visualization of traumatic injury to the pancreas, with the "direct" CT findings of parenchymal laceration or fracture, and/or pancreatic duct laceration or transection. Other, "indirect" CT findings of post-traumatic pancreatic injury are: 1) hypodensity surrounding the organ, indicating any combination of blood, pancreatic juice, or edema fluid, and 2) indistinctness ("smudginess") of the anterior pararenal fascia, and/or of the perirenal (Gerota's) fascia, secondary to edematous change in these locations.2,3,5

Because, in part, of the organ's retroperitoneal location, blunt-abdominal traumatic injuries to the pancreas can often be occult, with the clinical signs of fever, abdominal pain, leukocytosis, and hyperamylasemia being rather misleading, or altogether absent. Detection of pancreatic duct laceration injury is frequently not made until ERCP; delay in laparotomy can often be disastrous, with mortality reaching as high as 20% in some studies. Investigators have stressed the need for a high prescanning index of suspicion, and the watchful attention to subtle imaging findings in such cases.1,2,3,5

References:
1. "The Child with Abdominal Trauma", in Practical Pediatric Radiology, 2nd edition,
pages 335-356. SW Hilton and DK Edwards III, eds. WB Saunders Co., 1994.

2. Dodds, WJ, Taylor AJ, Erickson SJ, and Lawson TL: Traumatic fracture of the
pancreas: CT characteristics. J Comput Assist Tomogr 14:375-378, 1990.

3. Jeffrey RB, Federle MP, and Crass RA: Computed tomography of pancreatic
trauma. Radiology 147:491-494, 1983.

4. Patrick LE, Ball TI, Atkinson GO and Winn KJ: Pediatric blunt abdominal trauma:
periportal tracking at CT. Radiology 183:689-691, 1992.

5. Sivit CJ, Eichelberger MR, Taylor GA, Bulas DI, Gotschall CS, and Kushner DC:
Blunt pancreatic trauma in children: CT diagnosis. AJR 158:1097-1100, 1992.

6. Sivit CJ, Taylor GA, Newman KD, Bulas DI, Gotschall CS, Wright CJ and
Eichelberger MR: Safety-belt injuries in children with lap-belt ecchymoses: CT
findings in 61 patients. AJR 157:111-114, 1991.

7. Stalker HP, Kaufman RA and Towbin R: Patterns of liver injury in childhood: CT
analysis. AJR 147:1199-1205, 1986.

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