1.Imaging in abdominal trauma

2. Abdominal trauma Trauma causes I0% of deaths worldwide The third commonest cause of death after malignancy and vascular disease 3. Blunt abdominal trauma Vehicular trauma (75%) Blow to the abdomen (15%) Fall from height (6-9%) Others Domestic accidents Fights Iatrogenic cardiopulmonary resuscitation 4. Mechanism of injury Direct impact or movement of organs Compressive, stretching or shearing forces Solid Organs > Blood Loss Hollow Organs > Blood Loss and Peritoneal Contamination Retroperitoneal > Often asymptomatic initially 5. Penetrating abdominal injury Accidental Homicidal Iatrogenic Stab wounds Gun shot wounds Shrapnel wounds Impalements 6. Vectors of Force - Trauma "Packages" Right-sided Midline Left-sided R hepatic lobe R kidney Diaphragm pancreatic head duodenum IVC Left hepatic lobe Pancreatic body Aorta Transverse colon Duodenum Small bowel Spleen L kidney Diaphragm Pancreatic tail 7. Right-sided Trauma "Packages" 8. ACR Appropriateness Criteria Category A Hemodynamically unstable Clinically obvious major abdominal trauma Unresponsive profound hypotension Resuscitation with volume replacement. Not respond to resuscitation Operating room without imaging 9. UNSTABLE INVESTIGATION AVAILABILITY F A S T D P L FREE FLUID BLOOD NO YES CONTINUE RESUSCITATION LAPAROTOMY HEMODYNAMIC STABILITY ? 10. Category B Hemodynamically stable Mild to moderate responsive hypotension Significant trauma and have at least moderate suspicion of intra-abdominal injury based on clinical signs and symptoms These patients should be evaluated by imaging 11. Category C Hemodynamically stable Patients with hematuria after blunt abdominal trauma All patients with gross hematuria and pelvic fracture require additional imaging of the bladder to exclude bladder rupture 12. STABLE CONSCIOUS , RESPONSIVE YES NO SUSPICION OF ABDOMINAL INJURY YESNO C T CLINICAL FOLLOW- UP 13. What is FAST? A focused, goal directed, sonographic examination of the abdomen Goal is presence of haemoperitoneum or haemopericardium Can be integrated into the primary or secondary survey and can be performed quickly, without removing patients from the clinical arena Focused Assessment with Sonography for Trauma 14. What FAST is NOT A definitive diagnostic investigation A substitute for CT 15. The ABCDE of Trauma A - Airway B - Breathing C - Circulation (FAST) D - Disability E - Environment and Exposure 16. The FAST examination FAST examines four areas for free fluid: Perihepatic & hepato-renal space Perisplenic Pelvis Pericardium 17. The perihepatic scan The hepatorenal space (pouch of Morison) most dependent part of the upper peritoneal cavity The probe is placed in the right mid- to posterior axillary line at the level of the 12th ribs. 18. The perihepatic scan 19. The perihepatic scan Blood shows as a hypoechoic black stripe between the capsule liver and the fatty fascia of the kidney 20. Perihepatic scan 21. Perisplenic window Transducer positioned in left posterior axillary line between 10th and 11th ribs with beam in coronal plane. Demonstrates spleen, kidney and diaphragm May be marred by acoustic shadows from ribs May be improved by imaging patient whilst in full inspiration. 22. Abnormal perisplenic window 23. The pelvic scan The pelvic examination visualises the cul-de-sac: the Pouch of Douglas in females and the rectovesical pouch in the male Most dependent portion of the lower abdomen and pelvis, where fluid will collect The transducer is placed midline just superior to the symphysis pubis 24. The pericardial scan For the subxiphoid view, the transducer- probe should be placed in the subxiphoid area and directed into the chest toward the left shoulder so as to view the diaphragm and heart. This view can be difficult to obtain if the patient is experiencing significant abdominal pain. 25. Subxiphoid view of cardiac anatomy 26. Subxiphoid view Normal subcostal view of pericardium Positive FAST demonstrating pericardial effusion 27. FAST: Strengths and Limitations Strengths Rapid (~2 mins) Portable Inexpensive Technically simple, easy to train Can be performed serially Useful for guiding triage decisions in trauma patients Limitations Does not typically identify source of bleeding Requires extensive training to assess parenchyma reliably Limited in detecting 100 HU Extravasation of contrast medium (vascular or urinary) 31. SENTINEL CLOT SIGN Clotted blood adjacent to the site of injury is of higher attenuation value than unclotted blood which flows away . When the source of intraperitoneal bleed not evident, the location of highest attenuating blood clot is a clue to the most likely source 32. Spleen The spleen is the most commonly injured organ in blunt abdominal trauma 40% of all solid organ injuries 33. Plain film findings for spleen trauma left lower rib fracture The classic triad indicative of acute splenic rupture Left hemidiaphragm elevation Left lower lobe atelectasis Pleural effusion 34. Parenchymal Contusion Hypodense intraparenchymal area with irregular contours 35. Parenchymal Laceration Superficial, linear hypodensity, usually less than 3 cm in length Fracture - involves two visceral surfaces, or if its length is more than 3 cm Multiple fractures - Scattered spleen 36. Subcapsular Hematoma Crescent-shaped perisplenic hematoma Compresses the splenic parenchyma 37. Vascular Trauma The most dangerous vascular traumatic lesions are arterial lesions Irregular area of increased density relative to background spleen Typically the attenuation value is within 10 HU of the adjacent artery 38. Delayed splenic rupture Bleeding due to splenic injury occurring more than 48 h after blunt trauma following an apparently normal CT examination Due to ruptures of subcapsular splenic haematomas. 39. Splenic CT Injury Grading Scale Grade I Laceration(s) < 1 cm deep Subcapsular hematoma < 1cm diameter Grade II Laceration(s) 1-3 cm deep Subcapsular or central hematoma l-3cm diameter Grade III Laceration(s) 3-10 cm deep Subcapsular or central hematoma 3-10 cm diameter Grade IV Laceration(s) > 10 cm deep Subcapsular or central hematoma > 10cm diameter Grade V Splenic tissue maceration or devascularization 40. Simply : Grade 1 is less than 1 cm. Grade 2 is about 2 cm (1-3 cm). Grade 3 is more than 3 cm. Grade 4 is more than 10 cm. Grade 5 is total devascularization or maceration. 41. Contrast blush A contrast blush is defined as an area of high density with density measurements within 10 HU compared to the nearby vessel (or aorta). The differential diagnosis is: Active arterial extravasation Post-traumatic pseudoaneurysm Post-traumatic AV fistula 42. Contrast-enhanced CT: there is frank arterial bleeding from the splenic artery associated with a fragmented spleen. Extensive haemoperitoneum is also present 43. SPLENIC INJURIES - Management Grade I-III:Often arterial hemorrhage, therefore nonoperative management less successful Grade IV-V: almost invariably require operative intervention Delayed hemorrhage (hours to weeks post-injury): 8-21% 44. Liver The liver is the second most commonly injured organ in abdominal trauma. Between 70 and 90% of hepatic injuries are minor Right lobe most commonly affected 45. Abdominal Trauma Protocol Blunt injury -deceleration, crush, weapon (e.g. bat) venous phase ~70 secs Delayed scan if injury present; ~3-5 mins Penetrating injury: knives, gun Same as blunt Additional scan after rectal contrast material 46. Associated injuries: 2/3 have hemoperitoneum 45% have associated splenic injury 33% have rib fractures Duodenal or pancreatic injury Biliary injury: hematobilia, biloma, biliary ascites, bile duct disruption Ultrasound sensitive for grade 3 or greater 47. Radiological overview of liver injury: Right lobe> left lobe; 3:1 Posterior segment most common (fixed by coronary ligament) CT imaging method of choice 48. Features with impact on the management and the prognosis Number of segments involved by the lacerations (significant if at least three segments are involved) Central or subcapsular location of the lacerations and contusions Extension of lesions within the porta hepatis or the gallbladder fossa Importance of the hemoperitoneum Vascular lesions with active bleeding or sentinel clot sign 49. Green arrow: oval shaped hypodense area consistent with hematoma Yellow arrow: linear shaped hypodense area consistent with laceration. Notice that this laceration crosses the left portal vein Blue arrow: vague ill defined hypodense area consistent with contusion Fluid around the liver There is almost a transsection of the liver, but both lobes do enhance so there is still normal vascular supply. 50. Classification (AAST) I-Subcapsular hematoma 3cm diameter. 53. IV-Parenchymal/supcapsular hematoma> 10cm in diameter, lobar destruction, 54. V- Global destruction or devascularization of the liver. 55. VI-Hepatic avulsion 56. Periportal Edema Periportal hypodensities running in parallel to the portal branches Causes Diffusion from intraparenchymal bleeding Dilatation of periportal lymph vessels Vascular or focal bile duct dissection 57. PERI-PORTAL EDEMA 58. Multiple right lobe lacerations. This configuration has been described as a 'bear claw' appearance 59. Complications Biloma Delayed hemorrhage Hemobilia Hepatic infarcts Pseudoaneurysm AV fistula 60. Indications for surgical treatment in liver trauma Shock Active venous bleeding Trauma of the gallbladder Abdominal surgery necessary for other causes 61. Retroperitoneal Hemorrhage Retroperitoneal hemorrhage may arise from injuries to major vascular structures, hollow viscera, solid organs, or musculoskeletal structures or a combination 62. Small zone I (central) retroperitoneal hematoma 63. Large zone I (central) retroperitoneal hematoma with active extravasation 64. Large zone II (lateral) retroperitoneal hematoma 65. Pancreas Uncommon injury 1.1% incidence in penetrating trauma and only 0.2% in blunt trauma. Rarely an isolated injury. Usually part of a 'package injury Difficult to detect pancreatic injury on CT and one has to rely on ancillary findings Pancreatic duct injury cannot be directly visualized on CT. Deeper the laceration more likely that duct is injured 66. Laceration of the pancreatic neck without duct injury 67. Pancreatic transection (neck) with duct injury 68. Indirect Signs Edema with global pancreatic enlargement and loss of lobulation Peripancreatic fat infiltration Peripancreatic fluid, especially if it is located around the SMA or the omental bursa Thickening of the left anterior pararenal fascia or fluid in the anterior pararenal space Concomitant duodenal injury Hematic fluid between the dorsal surface of pancreas- Considered a DIRECT SIGN 69. AAST GRADING OF PANCREAS INJURY Grade Type of Injury Description of Injury I Hematoma Minor contusion without duct injury Laceration Superficial injury without duct injury II Hematoma Major contusion without duct injury or tissue loss Laceration Major laceration without duct injury or tissue loss III Laceration Distal transection or parenchymal injury with duct injury IV Laceration Proximal transection or parenchymal injury with probable duct injury (not involving ampulla) 70. Imaging of Renal Trauma Computed tomography (CT) is the modality of choice in the evaluation of blunt renal injury Injury to the kidney is seen in approximately 8% 10% of patients with blunt or penetrating abdominal injuries 71. Renal criteria for performing CT in abdominal trauma Macroscopic hematuria Microscopic hematuria with shock Important renal ecchymosis or fracture of the lumbar transverse process Open trauma involving the retroperitoneum Mechanism of deceleration (risk of pedicle injury) In children all types of posttraumatic hematuria 72. Computed Tomography Early and delayed CT scans through the kidneys are necessary Excretory-phase contrast (3min) The preferred technique Helical CT performed from the dome of the diaphragm Scanning parameters include Collimation of 7 mm, Pitch of 1.3, Image reconstruction intervals of 7 mm. 73. Subcapsular hematoma (category I) Crescent shaped hyperdensity, located in the periphery of the kidney 74. Laceration Hypodense, irregularly linear areas, typically distributed along the vessels and filled with blood. They are best analyzed at arterial phase Superficial (1 cm from the renal cortex) Renal medulla Collecting tubule system 75. Simple renal laceration (category I) 76. Major renal laceration without involvement of the collecting system (category II) 77. Major renal laceration involving the collecting system (category II) 78. Multiple renal lacerations (category III) 79. Shattered kidney (category III) 80. Segmental Infarct Triangular parenchymal area, with a widest part at the cortex, which is not enhanced during the different phases, with clear delineation 81. Segmental renal infarction (category II) 82. Traumatic occlusion of the main renal artery (category III) 83. Active arterial extravasation (category III) 84. Vein Pedicle Injury Incomplete or absent opacification of the renal vein Persistent nephrogram Reduction in excretion Nephromegaly 85. Laceration of the renal vein (category III) 86. Urinoma/Urohematoma Presence of a more or less significant breach of the collecting tube system, with urine escape reflected by extravasation of contrast medium on delayed imaging, in an extrarenal location 87. Avulsion of the ureteropelvic junction (category IV) 88. AAST organ injury severity scale grading system for kidney injury Grade 1 Contusion or contained and non -expanding subcapsular haematoma, without parenchymal laceration; haematuria Grade 2 Non -expanding, confined, perirenal haematoma or cortical laceration less than 1 cm deep; no urinary extravasation Grade 3 Parenchymal laceration extending more than 1 cm into cortex; no collecting system rupture or urinary extravasation Grade 4 Parenchymal laceration extending through the renal cortex, medulla and collecting system Grade 5 Pedicle injury or avulsion of renal hilum that devascularizes the kidney; completely shattered kidney; 89. CT Cystography Empty the bladder Instill the contrast retrograde through the Foley catheter of avg. 350-400 cc of contrast Image the pelvis BLADDER INJURY 90. CT classification TYPES 1. Bladder contusion 2. Intraperitoneal rupture 3. Interstitial bladder injury 4. Extraperitoneal rupture A. simple B. complex (bladder neck involved) 5. Combined bladder injury 91. Intraperitoneal rupture (type 2) Cystography Contrast in paracolic gutters, around bowel loops, pouch of Douglas and intraperitoneal viscera Pelvic fracture CT cystography Contrast in paracolic gutters, around bowel loops, pouch of Douglas and intraperitoneal viscera 92. Cystogram of intraperitoneal bladder rupture 93. Extraperitoneal rupture Cystography Simple: Flame-shaped extravasation around bladder Complex Extravasation extends beyond the pelvis Extravasation best seen on post-drainage films 94. CT of extraperitoneal bladder rupture 95. Type 5 (combined) rupture. 96. Intestinal and Mesenteric Traumas Bowel or mesentery injury occurs in 5% of patients with abdominal blunt trauma More common following open trauma, especially in injuries caused by firearms 97. Four CT findings should alert the radiologist 1. Focal fat infiltration 2. Interloop hematoma (sentinel clot sign) 3. Bowel wall thickening 4. Free intraperitoneal air 98. Small Bowel Injury Diffuse circumferential thickening Hypoperfused "shock" bowel Focal thickening Usually non-transmural injury Specific findings, rare Bowel content extravasation Focal bowel wall discontinuity Most common finding Unexplained non-physiologic free fluid (84%) Mesenteric stranding Focal bowel thickening Interloop fluid If in combination, strongly suggestive 99. Indirect findings of traumatic bowel perforation Peritoneal findings Sentinel clot Focal mesenteric infiltration GI findings Pneumoperitoneal air bubbles localized within the mesentery Focal wall thickening 100. Traumatic duodenal intramural hematoma 101. Periduodenal hemorrhage 102. Causes of bowel thickening related to trauma Contusion/hematoma Perforation Distal ischemia due to mesenteric lesion Bowel shock Secondary to peritonitis Bowel spasm 103. GI Ischemia Bowel ischemia Segmental (distal branch vessel injury) Diffuse thickening of small bowel wall - hypotensive shock bowel Typical CT signs Lack of parietal enhancement Thickening of bowel wall Parietal pneumatosis with presence of air inside the bowel wall Air in the mesentery and portal venous system 104. Role of Interventional Radiology Embolization Spleen Liver Pelvis Angioplasty + Stent Renal artery dissection 105. Agents for embolizations Gelfoam Soaked in an antibiotic solution restorable Can be cut in variable size May result in too distal embolization Risks for tissue infarction or late abscess formation Coils Have variable size, length, diameter Precise targeted delivery Expensive Need normal coagulation Metal stents Large-caliber patent artery 106. Advantages Embolization can decrease the amount of resuscitation fluid to maintain vital sign. Embolization can decrease shock index Operation with adjunct embolization can decrease the mortality rate Embolization is a promising way for stopping bleeding 107. Spleen Embolization 108. Role of MR Imaging in trauma demonstrated to be a near-equivalent technique to CT in the accurate appraisal of individual organ injuries The use of MRI at present confers no additional advantages in the initial trauma evaluation Limited access to patients for monitoring and resuscitation and the need for MR-compatible equipment pose major disadvantages. At present MRI is reserved for problem solving after the acute phase of trauma has passed 109. Take home messages: Abdominal injuries are often underappreciated radiologically either because of difficulty in assessment caused by condition of patient or because some signs take time to develop. CT , mdct in particular has revolutionized the management of trauma patient. One should be aware of indirect signs of trauma on CT Angiography has an increasing role in non operative management of abdominal trauma 110. Thank you