DOI: 10.1148/rg.245045002
RadioGraphics 2004;24:1381-1395
© RSNA, 2004
Blunt Trauma of the Pancreas and Biliary Tract: A Multimodality Imaging Approach to Diagnosis1
Avneesh Gupta, MD,
Joshua W. Stuhlfaut, MD,
Keith W. Fleming, MD,
Brian C. Lucey, MD and
Jorge A. Soto, MD
1 From the Department of Radiology, Boston University Medical Center and Boston University, Mass. Presented as an education exhibit at the 2003 RSNA scientific assembly. Received January 7, 2004; revision requested February 17 and received March 25; accepted March 29. All authors have no financial relationships to disclose. Address correspondence to A.G., Department of Radiology, Beth Israel Deaconess Medical Center, One Deaconess Rd, Boston, MA 02215 (e-mail: agupta@bidmc.harvard.edu).
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Abstract
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Injuries of the pancreas, gallbladder, and bile ducts due to blunt trauma are relatively uncommon and difficult to detect but are associated with high morbidity and mortality, especially if diagnosis is delayed. Accurate and early diagnosis is imperative, and imaging plays a key role in detection. Knowledge of the mechanisms of injury, the types of injuries, and the roles of various imaging modalities is essential for prompt and accurate diagnosis. Early recognition of disruption of the main pancreatic duct is important because such disruption is the principal cause of delayed complications. Computed tomography (CT) can demonstrate pancreatic parenchymal injuries and complications such as abscess, fistula, pancreatitis, and pseudocyst. CT findings can also suggest disruption of the pancreatic duct; however, the ability of CT to indicate this finding depends on the degree of parenchymal injury. Magnetic resonance (MR) cholangiopancreatography allows direct imaging of the pancreatic duct and sites of disruption. Gallbladder injuries can be detected with CT, ultrasonography, hepatobiliary scintigraphy, or MR cholangiopancreatography. CT findings include a collapsed gallbladder, wall thickening, inhomogeneous mural enhancement, and pericholecystic fluid. Bile duct injuries can be suggested with CT, which may show ascites and associated liver injuries, and can be confirmed with hepatobiliary scintigraphy.
© RSNA, 2004
Index Terms: Bile ducts, injuries, 76.41 • Bile ducts, leakage, 76.41 • Gallbladder, injuries, 762.41 • Gallbladder, perforation, 762.41 • Pancreas, injuries, 770.41
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LEARNING OBJECTIVES
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After reading this article and taking the test, the reader will be able to:
- Describe the mechanisms of pancreatic and biliary injuries due to blunt trauma.
- Identify the features of pancreatic and biliary injuries due to blunt trauma on images obtained with various modalities.
- List the late complications of pancreatic and biliary injuries due to blunt trauma.
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Introduction
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Blunt abdominal trauma may result in a variety of abdominal injuries. While injuries involving the liver and spleen are common and are usually detected by imaging without difficulty, pancreatic and biliary injuries may be more subtle. Moreover, these injuries may be overlooked in patients with extensive multiorgan trauma. Pancreatic and biliary injuries are uncommon but may be associated with high morbidity and mortality, particularly if diagnosis is delayed. Hence, early diagnosis is critical. We present a review of the imaging diagnosis of blunt pancreatic and biliary injuries by using a variety of imaging modalities.
In the acute setting, pancreatic injuries may result in death due to associated vascular injuries. However, delayed morbidity and mortality are usually caused by complications resulting from disruption of the pancreatic duct. Duct injury may lead to complications such as abscess, pseudocyst, fistula, and pancreatitis, which can be detected with computed tomography (CT). CT can readily demonstrate pancreatic parenchymal injuries, such as fractures and contusions, and may show additional abdominal injuries. Although the pancreatic duct cannot always be directly imaged with CT, duct disruption can be suggested based on the extent of parenchymal laceration. However, magnetic resonance (MR) cholangiopancreatography can directly image the duct and is useful in evaluating pancreatic duct injury.
Gallbladder injuries can initially be detected with CT. A collapsed gallbladder with pericholecystic fluid in a fasting patient suggests gallbladder perforation. Additional findings include wall thickening, discontinuous enhancement of the gallbladder wall, and pericholecystic fluid. Active hemorrhage, resulting from transection of the cystic artery, may be detected with CT enhanced with intravenous contrast material. Bile duct injuries can be suggested with CT, which may show liver lacerations, ascites, or focal perihepatic fluid collections. However, hepatobiliary scintigraphy is often required to show actively extravasating bile at the site of duct disruption. Knowledge of the key imaging findings of this uncommon but clinically significant group of injuries is critical in order to minimize morbidity and mortality in the blunt abdominal trauma victim.
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Pancreatic Injuries
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Injury to the pancreas is relatively uncommon, occurring in less than 2% of blunt abdominal trauma patients, although a prevalence of up to 12% has been reported (1–3). Pancreatic injuries may be difficult to diagnose clinically. Although uncommon, early diagnosis is crucial, since delayed complications such as fistula, abscess, sepsis, and hemorrhage may lead to significant mortality, occurring in up to 20% of cases (1,2). Most deaths occur within the first 48 hours following the traumatic event, usually due to acute hemorrhage from injury to the portal vein, splenic vein, or inferior vena cava (4–6). In contrast, death due to delayed complications is usually due to sepsis and multiorgan failure (7).
The pancreas is vulnerable to crushing injury in blunt trauma due to impact against the adjacent vertebral column. Two-thirds of pancreatic injuries occur in the pancreatic body, and the remainder occur equally in the head, neck, and tail (5). Isolated pancreatic injuries are rare, and associated injuries, especially to the liver, stomach, duodenum, and spleen, occur in over 90% of cases (4,5). Not uncommonly, three or more organs are involved (5). In adults, over 75% of blunt injuries to the pancreas are due to motor vehicle collisions. In children, bicycle injuries are common, and child abuse may result in pancreatic injuries in infants (3).
Symptoms and clinical findings are often nonspecific and unreliable. The classic triad of fever, leukocytosis, and elevation of serum amylase levels is rarely encountered (1). Elevation of serum amylase and lipase levels may be seen in only up to 73% and 82% of cases, respectively (4). Moreover, amylase and lipase levels in diagnostic peritoneal lavage samples may be falsely negative, due to the retroperitoneal location of the pancreas-related fluid collections, which usually cannot be sampled with lavage (7).
The main source of delayed morbidity and mortality from pancreatic trauma is disruption of the pancreatic duct. Injuries that spare the pancreatic duct rarely result in morbidity or death (4). Disruption of the pancreatic duct is treated surgically or by therapeutic endoscopy with stent placement, while injuries without duct involvement are usually treated nonsurgically. Likewise, complications such as fistulas and abscesses are more likely to occur in patients with damage to the pancreatic duct. The risk of abscess or fistula formation in patients with disruption of the pancreatic duct approaches 25% and 50%, respectively (7,8). Conversely, patients without duct injuries develop abscess or fistula in less than 10% of cases (7). As such, it is critical that imaging focus on the integrity of the duct or findings that suggest damage to the pancreatic duct.
Injuries to the pancreatic head are almost twice as likely to be fatal (28%) than injuries to the tail (16%), likely due to the involvement of the inferior vena cava, superior mesenteric vein, or portal vein associated with pancreatic head injuries (1). In addition, the location of injury influences the surgical approach. Since the proportion of islet cells is highest in the tail of the pancreas, removal of greater than 50% of the pancreas may lead to glucose regulation abnormalities, and pancreas-sparing procedures are often attempted in these cases (7). Duct injuries occurring in the tail of the pancreas may be treated successfully by partial pancreatectomy with little risk of endocrine or exocrine dysfunction. Pancreatitis occurs in 6%–10% of cases and may lead to significant morbidity and mortality, particularly in patients with hemorrhagic pancreatitis (7,8). Treatment of pancreatitis consists of bowel rest, nasogastric suction, and nutritional support (7).
Computed Tomography
CT is routinely used as first-line imaging in the acute trauma patient and can be helpful in defining injuries to the pancreas and associated complications. For blunt abdominal trauma, CT images are usually obtained in the portovenous phase, 60–70 seconds after injection of iodinated contrast media. Ideally, the section collimation is 5 mm or less, with at least a 20% overlap between adjacent reconstructed images. Previous studies of single-detector CT with 10-mm collimation have shown limited sensitivity and specificity for detection of pancreatic injuries, not exceeding 80% (2,4). However, sensitivity and specificity are likely to be improved with multidetector CT and thinner collimation, although reports in the literature, to our knowledge, are lacking.
Direct signs of pancreatic injury include pancreatic laceration, transection, and comminution (Figs 1, 2). Fluid collections, such as hematomas,pseudocysts, and abscesses, are often seen communicating with the pancreas at the site of fracture or transection (Figs 3, 4). Focal enlargement of the pancreas and peripancreatic fluid are suggestive of pancreatic injury, and faint fracture lines may be seen on close inspection (Figs 5, 6). Peripancreatic fat stranding, hemorrhage, and fluid between the splenic vein and pancreas are useful secondary signs (Table 1). Although CT may not always directly demonstrate the pancreatic duct, injury to the duct can be suggested based on the degree of parenchymal injury. One CT grading scheme has been devised, which parallels the surgical classification of Moore (1): grade A, pancreatitis or superficial laceration (<50% pancreatic thickness); grade B1, deep laceration (>50% pancreatic thickness) of the pancreatic tail (Fig 7); grade B2, transection of the pancreatic tail; grade C1, deep laceration of the pancreatic head; and grade C2, transection of the pancreatic head.
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Figure 1a. Fracture of the pancreatic neck in a 35-year-old woman after a motor vehicle collision. (a, b) Axial contrast-enhanced CT scans show extensive liver lacerations (a) and a fracture line at the pancreatic neck (arrowhead in b). (c) Transverse ultrasonographic (US) image shows fluid separating the pancreatic fragments at the fracture site (arrowhead). (d) Image from endoscopic retrograde cholangiopancreatography (ERCP) shows a large collection of extravasated contrast material (arrowheads), which indicates disruption of the pancreatic duct.
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Figure 1b. Fracture of the pancreatic neck in a 35-year-old woman after a motor vehicle collision. (a, b) Axial contrast-enhanced CT scans show extensive liver lacerations (a) and a fracture line at the pancreatic neck (arrowhead in b). (c) Transverse ultrasonographic (US) image shows fluid separating the pancreatic fragments at the fracture site (arrowhead). (d) Image from endoscopic retrograde cholangiopancreatography (ERCP) shows a large collection of extravasated contrast material (arrowheads), which indicates disruption of the pancreatic duct.
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Figure 1c. Fracture of the pancreatic neck in a 35-year-old woman after a motor vehicle collision. (a, b) Axial contrast-enhanced CT scans show extensive liver lacerations (a) and a fracture line at the pancreatic neck (arrowhead in b). (c) Transverse ultrasonographic (US) image shows fluid separating the pancreatic fragments at the fracture site (arrowhead). (d) Image from endoscopic retrograde cholangiopancreatography (ERCP) shows a large collection of extravasated contrast material (arrowheads), which indicates disruption of the pancreatic duct.
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Figure 1d. Fracture of the pancreatic neck in a 35-year-old woman after a motor vehicle collision. (a, b) Axial contrast-enhanced CT scans show extensive liver lacerations (a) and a fracture line at the pancreatic neck (arrowhead in b). (c) Transverse ultrasonographic (US) image shows fluid separating the pancreatic fragments at the fracture site (arrowhead). (d) Image from endoscopic retrograde cholangiopancreatography (ERCP) shows a large collection of extravasated contrast material (arrowheads), which indicates disruption of the pancreatic duct.
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Figure 2a. Fracture of the pancreatic neck in a 36-year-old woman after a motor vehicle collision. (a) Axial CT scan obtained with intravenous contrast material shows separation of the pancreatic head from the body and tail along with extravasation of contrast material (arrowheads), which indicates active hemorrhage. (b) ERCP image shows active extravasation of contrast material (arrowheads) due to transection of the pancreatic duct. (c, d) Intraoperative photographs show the pancreatic fracture (arrowheads in c) and anastomosis of the pancreatic tail with the jejunum (arrowheads in d). Note the pancreatic head (arrow in d), which has been oversewn at the site of fracture. (e) Axial CT scan obtained with intravenous contrast material after surgical repair shows anastomosis of the pancreatic tail with the jejunum (arrowhead). Note the pancreatic head fragment (arrow).
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Figure 2b. Fracture of the pancreatic neck in a 36-year-old woman after a motor vehicle collision. (a) Axial CT scan obtained with intravenous contrast material shows separation of the pancreatic head from the body and tail along with extravasation of contrast material (arrowheads), which indicates active hemorrhage. (b) ERCP image shows active extravasation of contrast material (arrowheads) due to transection of the pancreatic duct. (c, d) Intraoperative photographs show the pancreatic fracture (arrowheads in c) and anastomosis of the pancreatic tail with the jejunum (arrowheads in d). Note the pancreatic head (arrow in d), which has been oversewn at the site of fracture. (e) Axial CT scan obtained with intravenous contrast material after surgical repair shows anastomosis of the pancreatic tail with the jejunum (arrowhead). Note the pancreatic head fragment (arrow).
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Figure 2c. Fracture of the pancreatic neck in a 36-year-old woman after a motor vehicle collision. (a) Axial CT scan obtained with intravenous contrast material shows separation of the pancreatic head from the body and tail along with extravasation of contrast material (arrowheads), which indicates active hemorrhage. (b) ERCP image shows active extravasation of contrast material (arrowheads) due to transection of the pancreatic duct. (c, d) Intraoperative photographs show the pancreatic fracture (arrowheads in c) and anastomosis of the pancreatic tail with the jejunum (arrowheads in d). Note the pancreatic head (arrow in d), which has been oversewn at the site of fracture. (e) Axial CT scan obtained with intravenous contrast material after surgical repair shows anastomosis of the pancreatic tail with the jejunum (arrowhead). Note the pancreatic head fragment (arrow).
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Figure 2d. Fracture of the pancreatic neck in a 36-year-old woman after a motor vehicle collision. (a) Axial CT scan obtained with intravenous contrast material shows separation of the pancreatic head from the body and tail along with extravasation of contrast material (arrowheads), which indicates active hemorrhage. (b) ERCP image shows active extravasation of contrast material (arrowheads) due to transection of the pancreatic duct. (c, d) Intraoperative photographs show the pancreatic fracture (arrowheads in c) and anastomosis of the pancreatic tail with the jejunum (arrowheads in d). Note the pancreatic head (arrow in d), which has been oversewn at the site of fracture. (e) Axial CT scan obtained with intravenous contrast material after surgical repair shows anastomosis of the pancreatic tail with the jejunum (arrowhead). Note the pancreatic head fragment (arrow).
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Figure 2e. Fracture of the pancreatic neck in a 36-year-old woman after a motor vehicle collision. (a) Axial CT scan obtained with intravenous contrast material shows separation of the pancreatic head from the body and tail along with extravasation of contrast material (arrowheads), which indicates active hemorrhage. (b) ERCP image shows active extravasation of contrast material (arrowheads) due to transection of the pancreatic duct. (c, d) Intraoperative photographs show the pancreatic fracture (arrowheads in c) and anastomosis of the pancreatic tail with the jejunum (arrowheads in d). Note the pancreatic head (arrow in d), which has been oversewn at the site of fracture. (e) Axial CT scan obtained with intravenous contrast material after surgical repair shows anastomosis of the pancreatic tail with the jejunum (arrowhead). Note the pancreatic head fragment (arrow).
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Figure 3a. Large pseudocyst due to transection of the pancreatic duct in a 37-year-old man several weeks after blunt trauma. (a) Axial contrast-enhanced CT scan shows a large, loculated fluid collection (*) within the lesser sac, between the fragments of the pancreatic head and body. (b) Axial contrast-enhanced CT scan obtained after percutaneous drainage shows a catheter (arrowheads) within the pseudocyst. (c) ERCP image shows extravasation of contrast material (arrowheads), thus confirming the transection of the pancreatic duct. Note the drainage catheter within the collection (arrow). A stent was placed in the pancreatic duct during endoscopy (not shown). (d) Axial contrast-enhanced CT scan obtained several weeks after drainage shows resolution of the pseudocyst. Note the stent in the pancreatic duct (arrowhead) and the drainage catheter at the former site of the pseudocyst (arrow). (e) ERCP image obtained the same day as d shows no extravasation of contrast material, thus confirming the integrity of the pancreatic duct.
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Figure 3b. Large pseudocyst due to transection of the pancreatic duct in a 37-year-old man several weeks after blunt trauma. (a) Axial contrast-enhanced CT scan shows a large, loculated fluid collection (*) within the lesser sac, between the fragments of the pancreatic head and body. (b) Axial contrast-enhanced CT scan obtained after percutaneous drainage shows a catheter (arrowheads) within the pseudocyst. (c) ERCP image shows extravasation of contrast material (arrowheads), thus confirming the transection of the pancreatic duct. Note the drainage catheter within the collection (arrow). A stent was placed in the pancreatic duct during endoscopy (not shown). (d) Axial contrast-enhanced CT scan obtained several weeks after drainage shows resolution of the pseudocyst. Note the stent in the pancreatic duct (arrowhead) and the drainage catheter at the former site of the pseudocyst (arrow). (e) ERCP image obtained the same day as d shows no extravasation of contrast material, thus confirming the integrity of the pancreatic duct.
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Figure 3c. Large pseudocyst due to transection of the pancreatic duct in a 37-year-old man several weeks after blunt trauma. (a) Axial contrast-enhanced CT scan shows a large, loculated fluid collection (*) within the lesser sac, between the fragments of the pancreatic head and body. (b) Axial contrast-enhanced CT scan obtained after percutaneous drainage shows a catheter (arrowheads) within the pseudocyst. (c) ERCP image shows extravasation of contrast material (arrowheads), thus confirming the transection of the pancreatic duct. Note the drainage catheter within the collection (arrow). A stent was placed in the pancreatic duct during endoscopy (not shown). (d) Axial contrast-enhanced CT scan obtained several weeks after drainage shows resolution of the pseudocyst. Note the stent in the pancreatic duct (arrowhead) and the drainage catheter at the former site of the pseudocyst (arrow). (e) ERCP image obtained the same day as d shows no extravasation of contrast material, thus confirming the integrity of the pancreatic duct.
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Figure 3d. Large pseudocyst due to transection of the pancreatic duct in a 37-year-old man several weeks after blunt trauma. (a) Axial contrast-enhanced CT scan shows a large, loculated fluid collection (*) within the lesser sac, between the fragments of the pancreatic head and body. (b) Axial contrast-enhanced CT scan obtained after percutaneous drainage shows a catheter (arrowheads) within the pseudocyst. (c) ERCP image shows extravasation of contrast material (arrowheads), thus confirming the transection of the pancreatic duct. Note the drainage catheter within the collection (arrow). A stent was placed in the pancreatic duct during endoscopy (not shown). (d) Axial contrast-enhanced CT scan obtained several weeks after drainage shows resolution of the pseudocyst. Note the stent in the pancreatic duct (arrowhead) and the drainage catheter at the former site of the pseudocyst (arrow). (e) ERCP image obtained the same day as d shows no extravasation of contrast material, thus confirming the integrity of the pancreatic duct.
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Figure 3e. Large pseudocyst due to transection of the pancreatic duct in a 37-year-old man several weeks after blunt trauma. (a) Axial contrast-enhanced CT scan shows a large, loculated fluid collection (*) within the lesser sac, between the fragments of the pancreatic head and body. (b) Axial contrast-enhanced CT scan obtained after percutaneous drainage shows a catheter (arrowheads) within the pseudocyst. (c) ERCP image shows extravasation of contrast material (arrowheads), thus confirming the transection of the pancreatic duct. Note the drainage catheter within the collection (arrow). A stent was placed in the pancreatic duct during endoscopy (not shown). (d) Axial contrast-enhanced CT scan obtained several weeks after drainage shows resolution of the pseudocyst. Note the stent in the pancreatic duct (arrowhead) and the drainage catheter at the former site of the pseudocyst (arrow). (e) ERCP image obtained the same day as d shows no extravasation of contrast material, thus confirming the integrity of the pancreatic duct.
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Figure 4a. Transection of the pancreatic neck in a 15-year-old boy after a motor vehicle collision. (a) Axial contrast-enhanced CT scan shows a complete fracture of the pancreatic neck with fluid and hemorrhage between the pancreatic fragments; the fluid and hemorrhage track between the pancreas and splenic vein (arrowheads). (b) Axial contrast-enhanced CT scan obtained 5 days later shows expanding fluid collections (*). (c) Endoscopic retrograde pancreatogram shows extravasation of contrast material (arrow), thus confirming the transection of the pancreatic duct. A stent was subsequently placed in the pancreatic duct during endoscopy. (d) Axial contrast-enhanced CT scan obtained 1 month later shows resolution of the fluid collections. Note the indwelling stent (arrows).
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Figure 4b. Transection of the pancreatic neck in a 15-year-old boy after a motor vehicle collision. (a) Axial contrast-enhanced CT scan shows a complete fracture of the pancreatic neck with fluid and hemorrhage between the pancreatic fragments; the fluid and hemorrhage track between the pancreas and splenic vein (arrowheads). (b) Axial contrast-enhanced CT scan obtained 5 days later shows expanding fluid collections (*). (c) Endoscopic retrograde pancreatogram shows extravasation of contrast material (arrow), thus confirming the transection of the pancreatic duct. A stent was subsequently placed in the pancreatic duct during endoscopy. (d) Axial contrast-enhanced CT scan obtained 1 month later shows resolution of the fluid collections. Note the indwelling stent (arrows).
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Figure 4c. Transection of the pancreatic neck in a 15-year-old boy after a motor vehicle collision. (a) Axial contrast-enhanced CT scan shows a complete fracture of the pancreatic neck with fluid and hemorrhage between the pancreatic fragments; the fluid and hemorrhage track between the pancreas and splenic vein (arrowheads). (b) Axial contrast-enhanced CT scan obtained 5 days later shows expanding fluid collections (*). (c) Endoscopic retrograde pancreatogram shows extravasation of contrast material (arrow), thus confirming the transection of the pancreatic duct. A stent was subsequently placed in the pancreatic duct during endoscopy. (d) Axial contrast-enhanced CT scan obtained 1 month later shows resolution of the fluid collections. Note the indwelling stent (arrows).
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Figure 4d. Transection of the pancreatic neck in a 15-year-old boy after a motor vehicle collision. (a) Axial contrast-enhanced CT scan shows a complete fracture of the pancreatic neck with fluid and hemorrhage between the pancreatic fragments; the fluid and hemorrhage track between the pancreas and splenic vein (arrowheads). (b) Axial contrast-enhanced CT scan obtained 5 days later shows expanding fluid collections (*). (c) Endoscopic retrograde pancreatogram shows extravasation of contrast material (arrow), thus confirming the transection of the pancreatic duct. A stent was subsequently placed in the pancreatic duct during endoscopy. (d) Axial contrast-enhanced CT scan obtained 1 month later shows resolution of the fluid collections. Note the indwelling stent (arrows).
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Figure 5. Superficial pancreatic laceration without duct injury in a 17-year-old girl after a motor vehicle collision. Axial contrast-enhanced CT scan shows slight enlargement of the pancreatic tail with a faint laceration line (arrowheads) and surrounding free fluid (*). MR pancreatography performed the same day showed no injury to the pancreatic duct. The patient recovered after conservative treatment.
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Figure 6a. Superficial pancreatic laceration without duct injury in a 19-year-old man after a motor vehicle collision. Axial contrast-enhanced CT scans show a laceration of the distal pancreatic tail (arrows in a, arrow in b). No injury to the pancreatic duct was seen at laparotomy. The patient recovered after conservative treatment.
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Figure 6b. Superficial pancreatic laceration without duct injury in a 19-year-old man after a motor vehicle collision. Axial contrast-enhanced CT scans show a laceration of the distal pancreatic tail (arrows in a, arrow in b). No injury to the pancreatic duct was seen at laparotomy. The patient recovered after conservative treatment.
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Figure 7. Deep pancreatic laceration with duct injury in a 14-year-old girl after a motor vehicle collision. Axial contrast-enhanced CT scan shows a pancreatic laceration that involves more than 50% of the parenchymal thickness (arrow). Note the thickening of the pancreatic tail and the surrounding fluid. Transection of the pancreatic duct was confirmed at surgery, and resection of the pancreatic tail was performed.
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Grade A injuries, which spare the duct, are usually seen with an intact pancreatic duct by surgical grading, whereas grade B and C injuries correlate with duct disruption, especially when CT shows deep lacerations or pancreatic transection (1). In a study of 22 patients with pancreatic injuries who underwent CT prior to laparotomy, 10 of 10 patients with grade A injuries showed no pancreatic duct injury, whereas eight of eight patients with grade B2 or C2 injuries showed duct disruption at surgery (1).
MR Imaging
Since the integrity of the pancreatic duct is the main factor determining outcome following pancreatic injury and is used to guide therapy, evaluation of the duct is essential. In the past, ERCP was the only method available for evaluating pancreatic duct integrity. More recently, MR pancreatography has emerged as an attractive alternative for direct imaging of the pancreatic duct (9). MR pancreatography has the advantage of being noninvasive, faster, and more readily available than ERCP. The main pancreatic duct can be identified by MR pancreatography within the pancreatic head in up to 97% of cases and within the pancreatic tail in up to 83% (10). In addition, MR pancreatography may demonstrate abnormalities not visible at ERCP, such as fluid collections upstream of the site of duct transection, and is helpful in assessing parenchymal injury (Figs 8, 9) (11). Finally, MR pancreatography can be helpful in directing ERCP-guided therapy when ductal anomalies are present, such as pancreas divisum.
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Figure 8a. Disruption of the pancreatic duct with a large fluid collection in a 6-year-old boy after a motor vehicle collision. (a) Axial T2-weighted fat-suppressed MR image shows a fracture of the pancreatic tail (arrow) with associated fluid collections (*). (b) Coronal MR pancreatogram shows communication of the pancreatic duct (arrow) with a large fluid collection (*).
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Figure 8b. Disruption of the pancreatic duct with a large fluid collection in a 6-year-old boy after a motor vehicle collision. (a) Axial T2-weighted fat-suppressed MR image shows a fracture of the pancreatic tail (arrow) with associated fluid collections (*). (b) Coronal MR pancreatogram shows communication of the pancreatic duct (arrow) with a large fluid collection (*).
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Figure 9a. Pancreatic fracture with disruption of the pancreatic duct in a 27-year-old man after a motor vehicle collision. (a) Axial contrast-enhanced CT scan obtained at presentation shows a fracture of the pancreatic neck (arrow). (b) Axial contrast-enhanced CT scan obtained on day 6 shows expanding fluid collections. (c) Endoscopic retrograde pancreatogram shows transection of the pancreatic duct (arrow) and extravasation of contrast material as large fluid collections (*). However, the segment of the duct upstream of the collections is not demonstrated. (d) Endoscopic retrograde pancreatogram shows a stent in the pancreatic duct (arrow), which was placed during endoscopy. (e, f) Coronal MR images, obtained with the rapid acquisition with relaxation enhancement sequence (e) and with maximum intensity projection reformation of three-dimensional fast spin-echo data (f), show two large fluid collections (*). The segment of the pancreatic duct upstream of the collections is clearly demonstrated (arrow). (g, h) Axial fat-suppressed T1-weighted (g) and T2-weighted (h) MR images obtained 1 month later show resolution of the fluid collections with a residual fracture line (arrows).
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Figure 9b. Pancreatic fracture with disruption of the pancreatic duct in a 27-year-old man after a motor vehicle collision. (a) Axial contrast-enhanced CT scan obtained at presentation shows a fracture of the pancreatic neck (arrow). (b) Axial contrast-enhanced CT scan obtained on day 6 shows expanding fluid collections. (c) Endoscopic retrograde pancreatogram shows transection of the pancreatic duct (arrow) and extravasation of contrast material as large fluid collections (*). However, the segment of the duct upstream of the collections is not demonstrated. (d) Endoscopic retrograde pancreatogram shows a stent in the pancreatic duct (arrow), which was placed during endoscopy. (e, f) Coronal MR images, obtained with the rapid acquisition with relaxation enhancement sequence (e) and with maximum intensity projection reformation of three-dimensional fast spin-echo data (f), show two large fluid collections (*). The segment of the pancreatic duct upstream of the collections is clearly demonstrated (arrow). (g, h) Axial fat-suppressed T1-weighted (g) and T2-weighted (h) MR images obtained 1 month later show resolution of the fluid collections with a residual fracture line (arrows).
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Figure 9c. Pancreatic fracture with disruption of the pancreatic duct in a 27-year-old man after a motor vehicle collision. (a) Axial contrast-enhanced CT scan obtained at presentation shows a fracture of the pancreatic neck (arrow). (b) Axial contrast-enhanced CT scan obtained on day 6 shows expanding fluid collections. (c) Endoscopic retrograde pancreatogram shows transection of the pancreatic duct (arrow) and extravasation of contrast material as large fluid collections (*). However, the segment of the duct upstream of the collections is not demonstrated. (d) Endoscopic retrograde pancreatogram shows a stent in the pancreatic duct (arrow), which was placed during endoscopy. (e, f) Coronal MR images, obtained with the rapid acquisition with relaxation enhancement sequence (e) and with maximum intensity projection reformation of three-dimensional fast spin-echo data (f), show two large fluid collections (*). The segment of the pancreatic duct upstream of the collections is clearly demonstrated (arrow). (g, h) Axial fat-suppressed T1-weighted (g) and T2-weighted (h) MR images obtained 1 month later show resolution of the fluid collections with a residual fracture line (arrows).
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Figure 9d. Pancreatic fracture with disruption of the pancreatic duct in a 27-year-old man after a motor vehicle collision. (a) Axial contrast-enhanced CT scan obtained at presentation shows a fracture of the pancreatic neck (arrow). (b) Axial contrast-enhanced CT scan obtained on day 6 shows expanding fluid collections. (c) Endoscopic retrograde pancreatogram shows transection of the pancreatic duct (arrow) and extravasation of contrast material as large fluid collections (*). However, the segment of the duct upstream of the collections is not demonstrated. (d) Endoscopic retrograde pancreatogram shows a stent in the pancreatic duct (arrow), which was placed during endoscopy. (e, f) Coronal MR images, obtained with the rapid acquisition with relaxation enhancement sequence (e) and with maximum intensity projection reformation of three-dimensional fast spin-echo data (f), show two large fluid collections (*). The segment of the pancreatic duct upstream of the collections is clearly demonstrated (arrow). (g, h) Axial fat-suppressed T1-weighted (g) and T2-weighted (h) MR images obtained 1 month later show resolution of the fluid collections with a residual fracture line (arrows).
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Figure 9e. Pancreatic fracture with disruption of the pancreatic duct in a 27-year-old man after a motor vehicle collision. (a) Axial contrast-enhanced CT scan obtained at presentation shows a fracture of the pancreatic neck (arrow). (b) Axial contrast-enhanced CT scan obtained on day 6 shows expanding fluid collections. (c) Endoscopic retrograde pancreatogram shows transection of the pancreatic duct (arrow) and extravasation of contrast material as large fluid collections (*). However, the segment of the duct upstream of the collections is not demonstrated. (d) Endoscopic retrograde pancreatogram shows a stent in the pancreatic duct (arrow), which was placed during endoscopy. (e, f) Coronal MR images, obtained with the rapid acquisition with relaxation enhancement sequence (e) and with maximum intensity projection reformation of three-dimensional fast spin-echo data (f), show two large fluid collections (*). The segment of the pancreatic duct upstream of the collections is clearly demonstrated (arrow). (g, h) Axial fat-suppressed T1-weighted (g) and T2-weighted (h) MR images obtained 1 month later show resolution of the fluid collections with a residual fracture line (arrows).
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Figure 9f. Pancreatic fracture with disruption of the pancreatic duct in a 27-year-old man after a motor vehicle collision. (a) Axial contrast-enhanced CT scan obtained at presentation shows a fracture of the pancreatic neck (arrow). (b) Axial contrast-enhanced CT scan obtained on day 6 shows expanding fluid collections. (c) Endoscopic retrograde pancreatogram shows transection of the pancreatic duct (arrow) and extravasation of contrast material as large fluid collections (*). However, the segment of the duct upstream of the collections is not demonstrated. (d) Endoscopic retrograde pancreatogram shows a stent in the pancreatic duct (arrow), which was placed during endoscopy. (e, f) Coronal MR images, obtained with the rapid acquisition with relaxation enhancement sequence (e) and with maximum intensity projection reformation of three-dimensional fast spin-echo data (f), show two large fluid collections (*). The segment of the pancreatic duct upstream of the collections is clearly demonstrated (arrow). (g, h) Axial fat-suppressed T1-weighted (g) and T2-weighted (h) MR images obtained 1 month later show resolution of the fluid collections with a residual fracture line (arrows).
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Figure 9g. Pancreatic fracture with disruption of the pancreatic duct in a 27-year-old man after a motor vehicle collision. (a) Axial contrast-enhanced CT scan obtained at presentation shows a fracture of the pancreatic neck (arrow). (b) Axial contrast-enhanced CT scan obtained on day 6 shows expanding fluid collections. (c) Endoscopic retrograde pancreatogram shows transection of the pancreatic duct (arrow) and extravasation of contrast material as large fluid collections (*). However, the segment of the duct upstream of the collections is not demonstrated. (d) Endoscopic retrograde pancreatogram shows a stent in the pancreatic duct (arrow), which was placed during endoscopy. (e, f) Coronal MR images, obtained with the rapid acquisition with relaxation enhancement sequence (e) and with maximum intensity projection reformation of three-dimensional fast spin-echo data (f), show two large fluid collections (*). The segment of the pancreatic duct upstream of the collections is clearly demonstrated (arrow). (g, h) Axial fat-suppressed T1-weighted (g) and T2-weighted (h) MR images obtained 1 month later show resolution of the fluid collections with a residual fracture line (arrows).
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Figure 9h. Pancreatic fracture with disruption of the pancreatic duct in a 27-year-old man after a motor vehicle collision. (a) Axial contrast-enhanced CT scan obtained at presentation shows a fracture of the pancreatic neck (arrow). (b) Axial contrast-enhanced CT scan obtained on day 6 shows expanding fluid collections. (c) Endoscopic retrograde pancreatogram shows transection of the pancreatic duct (arrow) and extravasation of contrast material as large fluid collections (*). However, the segment of the duct upstream of the collections is not demonstrated. (d) Endoscopic retrograde pancreatogram shows a stent in the pancreatic duct (arrow), which was placed during endoscopy. (e, f) Coronal MR images, obtained with the rapid acquisition with relaxation enhancement sequence (e) and with maximum intensity projection reformation of three-dimensional fast spin-echo data (f), show two large fluid collections (*). The segment of the pancreatic duct upstream of the collections is clearly demonstrated (arrow). (g, h) Axial fat-suppressed T1-weighted (g) and T2-weighted (h) MR images obtained 1 month later show resolution of the fluid collections with a residual fracture line (arrows).
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For assessing the parenchyma, fat-suppressed T1- and T2-weighted sequences are performed. MR pancreatograms are acquired by using heavily T2-weighted breath-hold or non–breath-hold sequences. Fast spin-echo (two-dimensional or three-dimensional) and rapid acquisition with relaxation enhancement (RARE) sequences performed in the coronal and axial planes are usually sufficient.
Endoscopic Retrograde Cholangiopancreatography
Although MR cholangiopancreatography has become the noninvasive imaging method of choice when evaluating for pancreatic duct injury, ERCP remains important because of its potential to provide diagnostic images and to direct image-guided therapy. ERCP is indicated when pancreatic injuries are detected at CT or MR imaging or if there is high clinical suspicion of ductal injury. ERCP can direct appropriate surgical repair or can be used for primary therapy by means of stent placement. Prior studies as well as experience from our institution suggest that certain mild pancreatic duct injuries, especially those shown at ERCP to be contained by the pancreatic parenchyma, may be treated with stent placement rather than surgical repair (12). When ERCP-guided stent placement is being considered, delay in therapy longer than 72 hours after the initial trauma may lead to increased complications and a prolonged hospital stay (12). As with MR pancreatography, patients in whom ERCP shows no pancreatic duct injury may be treated conservatively with clinical and laboratory follow-up.
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Biliary Tract Injuries
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Blunt abdominal trauma may result in injury to the biliary tract, including the gallbladder and intrahepatic and extrahepatic bile ducts. The most common location of biliary injury is the gallbladder, followed by the common bile duct and the intrahepatic ducts.
Injury to the gallbladder occurs in up to 2%–3% of blunt trauma patients undergoing laparotomy (13–15). The low prevalence may be due to the protective effect of the liver (16). Gallbladder injury is highly associated with additional injuries. Liver, splenic, and duodenal injuries are most common, occurring in up to 91%, 54%, and 54% of cases, respectively (14). Blunt trauma may also result in injury to the intrahepatic and extrahepatic bile ducts, although this is rare. As with gallbladder injury, bile duct injuries are usually associated with injuries to other organs.
Gallbladder and bile duct injury may occur due to torsion, shearing, or compression forces (13). Although the gallbladder is protected by the liver, certain factors may increase the risk for injury. Distention of the gallbladder in a preprandial state increases biliary pressure, making the gallbladder more vulnerable to compression injury (17). Extrahepatic duct injuries may occur at sites of anatomic fixation, such as the intrapancreatic portion of the common bile duct, frequently after blunt impact or acute deceleration, possibly with compression against the spine (18–20). Elevation of the liver following blunt trauma may cause stretching of the relatively fixed common duct (18). Injuries to the intrahepatic bile ducts are seen only in patients with severe liver lacerations (21).
In the acute setting, gallbladder injury may be associated with cystic artery transection, leading to major blood loss (17). Delayed complications of gallbladder and/or bile duct injury, such as sepsis, may result from biliary leakage. Sterile bile within the peritoneum undergoes continuous peritoneal reabsorption and may initially lead to surprisingly few symptoms (17). It has been reported that 50% of patients with bile in the peritoneum at surgery have no localizing symptoms preoperatively (17). Since bile in the peritoneum usually does not cause symptoms until infected, bile leakage may occur for weeks or months before being detected clinically (15,17,18). When signs and symptoms are present, they are nonspecific and include vague abdominal pain, nausea, vomiting, and occasionally jaundice (19). With extrahepatic bile duct injury, diagnosis may be particularly difficult; up to 20% of such injuries are not detected at surgery (19).
Injuries to the gallbladder may be classified into one of three main categories: contusion, laceration/perforation, or complete avulsion. In gen-eral, contusions are considered to represent intramural hematomas, are the mildest form of gallbladder injury, and are treated conservatively (14). Lacerations and perforations are full-thickness wall injuries, requiring cholecystectomy. Avulsion of the gallbladder may involve variable portions of the gallbladder, cystic duct, and artery and may lead to major blood loss (14).
Computed Tomography
Imaging findings of gallbladder trauma are often overshadowed by injuries to adjacent organs. Nevertheless, a variety of findings are helpful for diagnosing gallbladder trauma (Table 2). A collapsed gallbladder, particularly in a fasting patient with additional imaging signs of gallbladder injury, should raise the possibility of gallbladder perforation or avulsion. Thickening or poor definition of the gallbladder wall are highly suggestive signs of gallbladder wall injury (Figs 10, 11) but are not specific for any particular type of gallbladder injury (13). Pericholecystic fluid is often seen as well (22). However, the fluid may not originate from the gallbladder and may be due to associated solid organ injuries. Dense layering fluid within the gallbladder lumen may be an indication of intraluminal hemorrhage, although milk of calcium or vicarious excretion of intravenous contrast media from prior CT studies are pitfalls that may cause similar findings. Complete gallbladder avulsion is a rare complication, which may result in the gallbladder lying freely within the peritoneal cavity. When patients are evaluated for bile duct injury, CT may demonstrate ascites or intra-hepatic bile collections, especially in serial studies (21) (Table 3).
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Figure 10a. Laceration of the gallbladder in a 19-year-old man after a motor vehicle collision. Axial contrast-enhanced CT scans show multiple liver lacerations (arrowheads in a) and free intraperitoneal air (*). There is noncontinuous enhancement of the gallbladder wall (arrowheads in b) with surrounding free fluid. Note the duodenal hematoma (arrow in b) and nonenhancement of the right kidney, which were the result of massive crush injury. A gallbladder laceration was confirmed at surgery, and the patient underwent cholecystectomy.
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Figure 10b. Laceration of the gallbladder in a 19-year-old man after a motor vehicle collision. Axial contrast-enhanced CT scans show multiple liver lacerations (arrowheads in a) and free intraperitoneal air (*). There is noncontinuous enhancement of the gallbladder wall (arrowheads in b) with surrounding free fluid. Note the duodenal hematoma (arrow in b) and nonenhancement of the right kidney, which were the result of massive crush injury. A gallbladder laceration was confirmed at surgery, and the patient underwent cholecystectomy.
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Figure 11a. Gallbladder rupture and transection of the cystic artery due to massive blunt trauma in a 6-year-old boy after a motor vehicle collision. (a) Axial contrast-enhanced CT scan shows extensive liver lacerations and right adrenal hemorrhage. Note the collection of iodinated contrast material anterior to the portal vein (arrowheads); this finding indicates active hemorrhage due to disruption of the cystic artery. (b) Axial contrast-enhanced CT scan shows noncontinuous enhancement of the gallbladder mucosa (arrowheads). Note the active extravasation of contrast material (arrows). (c) Axial contrast-enhanced CT scan shows dense intraperitoneal fluid (*), which is consistent with hemorrhage. Gallbladder rupture, hemoperitoneum, and transection of the cystic artery were confirmed at laparotomy. The patient underwent cholecystectomy.
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Figure 11b. Gallbladder rupture and transection of the cystic artery due to massive blunt trauma in a 6-year-old boy after a motor vehicle collision. (a) Axial contrast-enhanced CT scan shows extensive liver lacerations and right adrenal hemorrhage. Note the collection of iodinated contrast material anterior to the portal vein (arrowheads); this finding indicates active hemorrhage due to disruption of the cystic artery. (b) Axial contrast-enhanced CT scan shows noncontinuous enhancement of the gallbladder mucosa (arrowheads). Note the active extravasation of contrast material (arrows). (c) Axial contrast-enhanced CT scan shows dense intraperitoneal fluid (*), which is consistent with hemorrhage. Gallbladder rupture, hemoperitoneum, and transection of the cystic artery were confirmed at laparotomy. The patient underwent cholecystectomy.
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Figure 11c. Gallbladder rupture and transection of the cystic artery due to massive blunt trauma in a 6-year-old boy after a motor vehicle collision. (a) Axial contrast-enhanced CT scan shows extensive liver lacerations and right adrenal hemorrhage. Note the collection of iodinated contrast material anterior to the portal vein (arrowheads); this finding indicates active hemorrhage due to disruption of the cystic artery. (b) Axial contrast-enhanced CT scan shows noncontinuous enhancement of the gallbladder mucosa (arrowheads). Note the active extravasation of contrast material (arrows). (c) Axial contrast-enhanced CT scan shows dense intraperitoneal fluid (*), which is consistent with hemorrhage. Gallbladder rupture, hemoperitoneum, and transection of the cystic artery were confirmed at laparotomy. The patient underwent cholecystectomy.
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Ultrasonography
Although generally not used for initial assessment of the trauma patient, US may be useful for evaluation of gallbladder wall thickness and intraluminal hemorrhage and for follow-up in patients with known gallbladder injury. US is of limited use for initial diagnosis of bile duct injury but may have a role in follow-up of contained intra- or perihepatic bilomas that are treated conservatively.
Hepatobiliary Scintigraphy
Hepatobiliary scintigraphy is a sensitive method for detection of biliary leak in patients with suspected gallbladder and biliary injuries (13). Unlike other imaging modalities, scintigraphy demonstrates physiologic biliary excretion and is helpful in detecting active bile leak. Delayed scanning at 4 hours is essential, as slow leaks may not be detected with earlier imaging (13). Scintigraphy is sensitive for detecting intraperitoneal bile leaks as well as contained bilomas, which may form in the liver after intrahepatic duct injury, and may also be useful for follow-up.
MR Cholangiopancreatography
The use of MR cholangiopancreatography in the setting of gallbladder trauma has not been well evaluated, with few case reports in the literature (23,24). As with CT, MR cholangiopancreatography may demonstrate collapse of the gallbladder, intraluminal hemorrhage, or pericholecystic fluid. In one report, gadolinium-enhanced sequences demonstrated a defect in the gallbladder wall, which was confirmed at surgery (24).
MR cholangiopancreatography has been used extensively for evaluation of iatrogenic trauma to the biliary ductal system (25–28). However, the potential applications for evaluating injuries resulting from blunt abdominal trauma have not been evaluated thoroughly, with only case reports in the literature (29). As with pancreatic injuries, advantages of MR cholangiopancreatography include noninvasiveness and greater availability than ERCP. In addition, MR cholangiopancreatography allows evaluation of the liver parenchyma and may demonstrate associated fluid collections. Mangafodipir trisodium (Teslascan; Amersham Health, Princeton, NJ), a hepatobiliary MR imaging contrast agent, provides good-quality MR cholangiograms with T1-weighted sequences (30). This agent can also demonstrate the exact origin and extent of bile leaks (27). Thus, MR examinations performed with this agent may allow both anatomic and functional imaging of the biliary tree and may help identify the exact site of injury (27). However, to our knowledge, the sensitivity of MR cholangiopancreatography performed with mangafodipir trisodium for detection and localization of bile duct injury has not been formally compared with that of ERCP.
Endoscopic Retrograde Cholangiopancreatography
ERCP continues to have an important role in diagnosis and therapy of biliary tract injuries. It may demonstrate the exact site of bile duct disruption (Fig 12) and may allow stent placement in selected bile duct injuries. Furthermore, ERCP may demonstrate the biliary system more easily than percutaneous transhepatic techniques, particularly if the bile ducts are nondilated and difficult to cannulate percutaneously.
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Figure 12a. Intrahepatic bile duct leak in a 20-year-old man after a high-speed motorcycle collision. (a) Axial contrast-enhanced CT scan shows a laceration of the right lobe of the liver (arrowheads) that extends to the hepatic surface. (b) Axial contras | |
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Abstract
LEARNING OBJECTIVES
