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MDCT TRAUMA PROTOCOL MADE EFFICIENT: TOTAL BODY SCANS Ruedi Ruedi F.-L. F.-L. Thoeni, Thoeni, M. M. D. D. Department Department of of Radiology Radiology and and Biomedical Biomedical Imaging Imaging University University of of California, California, San San Francisco Francisco Chief, Chief, Abdominal Abdominal Imaging, Imaging, SFGH SFGH SCBT/MR, San Diego 2010 No DISCLOSURE OBJECTIVES: MDCT FOR TRAUMA • Describe full body trauma protocol with 64-slice MDCT • Demonstrate combining evaluation of visceral organs with CTA including run off • Outline use of MPRs and 3D volume rendering • Display role for delayed imaging • Outline radiation issues Total Body MDCT Protocol in Trauma Scans Mode Gantry Rot. Speed 64 x 0.625 mm 1: 0.984 or 1.375 0.5 sec IV contrast 120-150 mL at 5 mL/sec saline flush 50 mL Based on body scout Head/neck Reconstruction thickness no iv 0.625 mm Chest IV, ~20 sec 1.25 mm Abdomen/pelvis IV, 80 sec 1.25 mm Delay, abdomen/pelvis 3-5 min Maybe cystogram to follow 1.25 mm 1.25 mm Trauma Brain, Face, C -spine C-spine PVA, resuscitated Trauma Chest Trauma Abdomen/Pelvis ? 24 yo shot in a nightclub Supine delayed Prone Cystogram ? Bladder injury? Total Body MDCT Protocol in Trauma If plain films demonstrate fractures in pelvic ring or long bones or penetrating trauma: Body part Delay Recon Thickness Noise Index CTA of pelvis, ~ 23 sec 0.625 mm long bones bolus tracking 21 Chest ~30 sec 24 Abd/pelvis 80 sec 24 Delayed scans 3-5 min 27-29 (If CTA of neck needed, done before chest) GSW Trauma Chest & LE GSW to Chest & LE Dose & Noise at Porta Hep. with Arms Down Arm position Noise* Radiation dose∗∗ Arms up 15.8 +/- 2.8 1076 (614-1831) One arm down 16.6 +/- 2.7 1312 (887-1805) Two arms down 17.8 +/- 2.2* 1381 (973-1737) Image quality decreased compared to standard but within acceptable diagnostic limits * P value for image noise: 0.002 ** P value for radiation dose: 0.000 Brink M, de Lange F, Oostveen LJ, et al Arm raising at exposure-controlled multidetector trauma CT of thoracoabdominal region: image quality, lower radiation dose. Radiology 2008; 249: 661-670 Multiplanar Reformations (MPR) Better appreciation of complexity of findings Increase efficiency Effective tool for communicating with clinicians •• Visceral Visceral organ organ injury injury (coronal!) (coronal!) •• Bony Bony fractures fractures (spine, (spine, pelvis) pelvis) •• CT CT angiography angiography S/P Fall from roof 3 Dimensional (3D) Reformations • Performed on separate workstation • Generated within minutes by technologist • Useful for preoperative planning of complicated bony trauma • Essential for CTA Run off Role of Delayed Imaging • Maybe used selectively or routinely • Obtained with an increased noise index • Clarifies injuries to: •• Kidneys Kidneys and and ureters ureters •• Solid Solid organs: organs: extravasation, extravasation, pseudo pseudo-aneurysm aneurysm or or arteriovenous arteriovenous fistula fistula •• Mesenteric Mesenteric injury injury or or other other arterial arterial injury injury •• Can Can estimate estimate size size of of bleed bleed Blunt Trauma to the Back (Fall) PV phase 80 sec Delay 33-5 -5 min. Blunt Trauma due to high -speed MVA high-speed PV phase 80 sec Delay 33-5 -5 min. PV phase 80 sec Delay 33-5 -5 min. Oral Contrast in Trauma • Not routinely given in blunt abdominal trauma • Delay in diagnosis • Risk of aspiration (trauma board) • Patient may have to go directly to the OR • “Surgical” bowel adequately depicted • Nearly static images of bowel with 64-slice • Optimal bowel wall enhancement • Positive oral contrast for penetrating trauma GSW Wound to the Abdomen Summary: Total Body CT Trauma Protocol • Trauma head, chest and abdomen based on total body scout • After head, do CTA when trauma to extremity or bony pelvis • Reconstruct head & CTA at 0.625 mm, rest at 1.25 mm • Thinner slices -> higher radiation • Reducing radiation: * Tube current modulation dose setting (Noise index) - 21 for CTA - 24 for chest/abdomen - 27-29 for delayed imaging * Sacrifice optimal visuals to sufficient diagnostic quality * Arms up whenever possible!