IMAGING OF BLUNT ABDOMINAL TRAUMA, PART I

Transcription

1 IMAGING OF BLUNT ABDOMINAL TRAUMA, PART I QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture. Ruedi F. Thoeni, M. D. D University of California, San Francisco SCBT-MR Summer Practicum, Williamsburg, 2009

2 Learning Objectives for blunt abd.. Trauma General imaging considerations in abd.. trauma Features and grading of trauma to liver Findings often associated with liver trauma Features and grading of trauma to spleen Features and grading of trauma to pancreas

3 ROLE OF CT IN TRAUMA To guide management of patients To identify patients with internal injury To triage patients for emergent intervention: Surgery Interventional management (endovascular)

4 DEDICATED ABD. TRAUMA MDCT Contrast Materials: Oral contrast (if possible): 3 cups of 450 ml of 2.2% Gastrografin (10 ml/450 of water) IV contrast: 3 cc/sec for 150 ml Rectal contrast (for penetrating trauma: 40 cc of Conray 60% in 1000 ml normal saline: use ml as tolerated Important: Clamp bladder catheter to achieve full distention of bladder

5 DEDICATED ABD. TRAUMA MDCT 16 (64) - slice MDCT: Detector configuration: 16 (64) x mm, reconstruction thickness and interval: 5 mm Scan delay: 80 sec or smart prep,, diaphragm to ischial tuberosity Important: Single acquisition: total body trauma CT scan: head, cervical spine, chest, abdomen & pelvis Delayed scans (5 min) optional: : parenchymal organs, excretory system incl. bladder, vasc. extravasation CT cystogram for bladder injury: : cc of 20 cc of 60% contrast/500 cc of sterile saline

6 IDENTIFY/CHARACTERIZE INTRA- PERITONEAL FLUID COLLECTIONS Always use ROI for fluid in trauma! Water density ( HU) Mixed density (10-20 HU): urinary bladder, bowel, gallbladder rupture Hemoperitoneum: CT attenuation > 30 HU Sentinel clot (45-70 HU): densest close to injury Active arterial extravasation: > 100 HU

7 HEMOPERITONEUM VS. WATER-DENSE TRAUMATIC INTRAPERITONEAL FLUID 45 HU B 15 HU 10 HU 85 HU

8 IDENTIFY LIFE-THREATENING INJURIES Active extravasation Massive hemorrhage Major vascular injuries Signs of shock Bowel perforation

9 IDENTIFY ACTIVE BLEEDING Active extrav. from spleen -> > embolization

10 LIVER INJURIES Prevalence: occurs in up to 25% of patients with blunt abdominal trauma undergoing CT Mortality ~ 4-12% overall 50-80% with juxtahepatic venous injury Matthes G, Stengel D, Seifert J, et al. Blunt liver injuries in polytrauma: results from a cohort study with regular use of whole body helical computed tomography.world J Surg 2003; 27:

11 LIVER TRAUMA: IDENTIFY Liver laceration Hematoma (54 HU, 28-82) 82) Active hemorrhage (155 HU, ) Juxtahepatic venous injury (Periportal low attenuation) (Flat IVC) Willmann JK, Roos JE, Platz A, et al. Multidetector CT: detection of active hemorrhage in patients with blunt abdominal trauma. AJR 2002; 179:

12 PARENCHYMAL INJURY TO LIVER BLUNT TRAUMA: Hematoma subcapsular or intraparenchymal hematoma Laceration linear, stellate, bear claw lacerations Bleeding recognize arterial or venous injury with extrav. (overall art. extrav. = 18.4%; spleen = 17.7%) PENETRATING TRAUMA: subcapsular hematoma & linear laceration, extrav.

13 GRADING HEPATIC INJURY Hematoma (subcapsular or parenchymal) I < 1cm diameter II 1-33 cm III > 3 cm Laceration I < 1 cm deep II 1-3 cm III > 3 cm Parenchymal disruption IV 25-75% of hepatic lobe, segments V >75% of hepatic lobe, >3 segments Juxtahepatic venous injury VI vena cava, central hepatic veins, avulsion American Association for the Surgery of Trauma and as modified by Mirvis, et al, Radiology 1989;171:27-32.

14 INTRAHEPATIC LAC, GRADE III > 3 cm, no hemoperitoneum Bear Claw Lac

15 LIVER INJURY: GRADE IV AND V IV: Parenchymal disruption: 1-3 segments V: Parenchymal disruption: > 3 segments

16 BARE AREA OF THE LIVER Injury to the bare area: right lobe injury more frequent than left about 25% of liver injuries limited to bare area Liver lacerations into the bare area: usually results in retroperitoneal bleed: bleeding into right anterior pararenal space or perirenal space

17 CT PREDICTOR OF FAILURE FOR NON- OPERATIVE MANAGEMENT Active bleeding on CT Injury grade above III injury of main trunks of hepatic veins twice as likely to fail hepatic veins injured in 13% of patients with liver injury IVC injured (retrohepatic IVC: 50% mortality) Overall nonoperative success rate: 80% in adults, 97% in children Pachter HL, Knudson MM, Esrig B, Ross S, Hoyt D, Cogbill T, et al. Status of nonoperative management of blunt hepatic injuries in 1995: a multicenter experience with 404 patients. J Trauma 1996; 40:

18 FOLLOW-UP CT IN BLUNT LIVER TRAUMA Indications for CT in low grades: abdominal pain in RUQ, jaundice, fever, anemia or melena Indications for CT in grades IV to VI: identify complications (7 to 10 days post injury*): bile leakage (biloma, bile peritonitis; 2.8 to 7.4%) delayed hemorrhage (1.7% to 5.9%) abscess (0.6% to 4%) pseudoaneurysm of hepatic artery & hemobilia (1%) * Pachter HL, Knudson MM, Esrig B, Ross S, Hoyt D, Cogbill T, et al. Status of nonoperative management of blunt hepatic injuries in 1995: a multicenter experience with 404 patients. J Trauma 1996; 40:

19 BILE LEAKS AAST guidelines for grading liver injury does not take into account bile leaks Difficult to predict who will develop a bile leak Bile leak asymptomatic in up to 50% Symptoms develop if bile infected or biloma large Gallbladder injury uncommon: 2-3% 2 with blunt trauma (distended gallbladder!)

20 LIVER LAC GRADE V + BILE LEAK Percutaneous Drainage of Biloma

21 FOLLOW-UP CT FINDINGS IN BLUNT LIVER TRAUMA Hepatic repair progresses predictably: Resolution Hemoperitoneum 1 week Laceration 3 weeks Subcapsular hematoma weeks Parenchymal homogeneity weeks Hematoma, biloma years Karp MP, Cooney DR, Pros GA, et al. The nonoperative management of pediatric hepatic trauma. J Pediatr Surg 1983; 18:

22 SPLENIC INJURIES Splenic injury most commonly injured organ following blunt abdominal trauma Incidence of splenic injury splenic injury accounts for 40-50% of patients with abdominal organ injury

23 GRADING SPLENIC INJURY Subcapsular hematoma I < 10% surface area II 10-50% III > 50% or expanding Parenchymal hematoma II < 5 cm diameter III > 5 cm or expanding Laceration (parenchyma) I < 1 cm II 1-3 cm III > 3 cm Devascularization (hilar( or segmental vessel damage-> > major devasc.) IV > 25% of spleen Shattered Spleen V completely shattered or hilar vascular injury, no perfusion Moore EE, Cogbill TH, Jurkovich GH, et al. Organ injury scaling: spleen and liver (1994 revision). J Trauma 1995; 38: Shanmuganathan,, et al. Radiology 2000; 217: 75-82

24 HILAR DEVASCULARISATION Grade IV

25 NONOPERATIVE MANAGEMENT Overall success rate: 65% Failed conservative management Grade % Surgical Intervention I 0% II 8% III 19% IV ~100% V all had initial surgery Knudson MM, Maull KI. Nonoperative management of solid organ injuries. Past, present, and future.surg Clin North Am Dec;79(6):

26 SPLENIC INJURIES: COMPLICATION Active hemorrhage hyperattenuating area on portal venous phase with persistent hyperattenuation or increase in size on 5 minute delay Pseudoaneurysm hyperattenuating area on portal venous phase with wash-out on 5 minute delay (acts like other vessels) Anderson SW, Varghese JC, Lucey BC, et al. Blunt Splenic Trauma: Delayed-Phase CT for Differentiation of Active Hemorrhage from Contained Vascular Injury in Patients. Radiology. 2007; 243:88-95.

27 SPLENIC PSEUDOANEURYSM Multiple pseudoaneurysms

28 PANCREATIC INJURIES Incidence: in 1% - 3% of blunt abd. trauma Greatest mortality when delay in Dx 70% of adults (15-30% children) have associated injuries Amylase initially is neither sensitive nor specific days later will be elevated in 80-90% Initial CT sensitivity 68-80% 80%

29 PANCREATIC INJURIES More common under 40 years of age Mechanism: compression against spine Association with liver and duodenal injuries CT findings: initially may be normal Early recognition of duct disruption important because of possible delayed complications: Fistula, pseudocyst, abscess

30 PANCREATIC ORGAN INJURY AAST SCALE Grade I (A*) minor contusion, superficial lac, duct intact Grade II (A) major contusion, major lac, duct intact Grade III (B) duct injury, distal transsection Grade IV (C) proximal transsection, ampulla injury Grade V (C) massive disruption of pancreatic head * Moore classification: Wong YC, Wang LJ, Lin BC, et al. CT grading of blunt pancreatic injuries: prediction of ductal disruption and surgical correlation. J Comput Assist Tomogr 1997; 21:

31 PANCREATIC INJURIES Grade I & II: minor/major contusion or laceration Grade III: distal duct disruption Grade IV: Proximal transsection, ampullary injury Grade V: Pancreas head, duodenal crush injury Patel et al, Br J Radiol 1998;71:

32 CT FINDINGS OF PANCREATIC INJURY Focal or diffuse enlargement/edema focal area of low attenuation = contusion look for asymmetry of the pancreatic septations heterogeneous enhancement Hemorrhage/fluid in anterior pararenal space between pancreas and splenic vein around SMA Duct injury (occurs in about 15% of patients) CT sensitivity low: ERCP or MRCP better; MDCT? implied disruption if laceration is > 50% pancreas thickness

33 PANCREATIC DISSECTION, GRADE III Immediately post trauma ERCP after CT

34 MIMICKER OF TRAUMATIC PANCREATITIS Overhydration Overhydration

35 MDCT OF PANCREATIC INJURY 9/95 (9.5%) patients with blunt abdominal trauma Six with MP duct injury, 3 without Detection of duct injury was 97.7% in pancreatic phase 100% in portal venous phase 96.8% in equilibrium phase High interobserver agreement Wong YC, Wang LJ, Fang JF, et al. MDCT of blunt pancreatic injuries: ies: can contrast- enhanced multiphasic CT detect pancreatic duct injuries? J Trauma 2008; 64:

36 TAKE HOME MESSAGE FOR INTRA- AND RETROPERITONEAL INJURY Dedicated trauma protocol Timing of iv contrast material critical (smart prep) Identify/characterize intraperitoneal fluid collections Identify active bleeding Identify abdominal parenchymal injuries Grade parenchymal injuries for management Obtain delayed scans in selected instances