MDCT of Traumatic Aortic Injury: New Concepts

Stuart E. Mirvis, MD, FACR

Department of Radiology & Maryland Shock-Trauma Center

University of Maryland School of Medicine

8th Nordic Trauma Radiology Course

Evolution in Diagnosis & Management of TAI

MDCT has improved sensitivity for detecting subtle TAI

As more patients are screened by CT ……increasing visualization of variant anatomy that can mimic TAI

MDCT reveals wider spectrum/nuances of TAI MH not a constant companion to TAI More treatment options requires more accurate

anatomical description of injuries and understanding their natural history

Rare cases still MCDT indeterminate* (IVUS, angio, endoluminal view, sonography)

*Sammer M, et al. Indeterminate CT Angiography in Blunt Thoracic Trauma:Is CT Angiography Enough? AJR 2007;189:603–608

Ductus remnant

Aortic spindle

Typical Aortic Injury Features

Location – 95+ % @ aortic isthmus Surrounding hematoma typical Pseudoaneurysm Intimal flaps Irregular, flattened contour Thrombus on flap Coarctation – 20-30% Small distal aorta – 10% Retrocrural hematoma – 20% Active bleed - rare

Typical Aortic Pseudoaneurysms

Aortic Coarctation / Small Aorta Sign

Thoracic spine fracture-dislocation and aortic wall hematoma

Distractive or translational force

Rare: 8 of 11,465 trauma admissions

From intimal tear to full thickness injury

Traumatic Aortic Dissection

Aortic injury embolism

Ductus and ductus variants

Diverticular Origin of Bronchial Artery

Aortic Injury Classification

Minor TAI: Contour irregularity, intimal flap +/- attached clot, intramural hematoma, pseudoaneurysm < 10% “normal” aortic diameter at same level (very conservative)

Major TAI: active bleeding, pseudoaneurysm > 10% of normal aortic diameter at same level, dissection

MH: Presence or absent

Minor Pseudoaneurysm

Minor Pseudoaneurysm

Contour Abnormality

Minor Aortic Injuries

Day 1 Day 1 Day 1

Day 2 Day 2 Day 8

Minor TAI – Intima and clot – Minimal MH Resolved

Day 8

Minor intimal tear - No MH

2 days later – no treatment

Day 0

Day 8

Day 28

Patients and Methods

IRB and HIPAA compliant Retrospective review of patients through Shock-Trauma Registry

(Jan. 2005 to May 2011) Excluded patients expired or had thoracic surgery before MDCT All CTs (initial and any F/U) reviewed by consensus of 3 radiologists

for TAI and +/- MH Determined management from imaging studies and medical records Injury status at time of last MDCT F/U 40 or 64-slice MDCT with 100 ml of 350mg% IV contrast and 50 ml

saline flush and full body scan technique Fischer’s Exact Test assessed probability of association between

TAI grade and MH (present/absent)

Results 115 patients (0.3%) with TAI among 40,479 admits 6.5

yr 42 classified as minor; 73 as major Minor TAI: 76% intimal flap, 24% shallow

pseudoaneurysm Among 42 minor – 23 treated without intervention;15

stented; 2 surgery (both 2005); 2 died before imaging (non-aortic cause)

33 of 42 (79%) minor injuries with MH and 9 (21%) had no MH; 3 of 73 major (4%) TAI no MH

Correlation of TAI grade and present/absent MH (p=0.0001) by Fischer exact test

Results

33 of 42 (79%) pts. had CT-A follow-up 21/33 (64%) stable;5(15%) improved;7

(21%) resolved Mean F/U = 32d, median 7d, range 1-210d

In press, European Radiology

Gavant ML. Helical CT grading of traumatic aortic injuries: Impact on clinical guidelines for medical and surgical management. Radiol Clinics of N Am. 1999;37:553-574.

Presley Trauma Center Grading System of Aortic Injury I. Normal aorta a. Nl thoracic aorta

b. Nl aorta + MH II. Minimal aortic injury a. Flap, PsAn < 1 cm. No MH b. Flap, PsAn < 1 cm. + MH III. Confined TAI a. > 1 cm well-defined PsAn with flap or thrombus. No great vessels injury + MH b. > 1 cm well-defined PsAn with flap or thrombus; not isthmic aortic site, +MH IV. Total disruption with irregular poorly defined PsAn and MH

Examples of minor TAI from Elvis Presley Trauma Center Criteria (Memphis)

Paul et al. Minimal aortic injury after blunt trauma: Selective nonoperative management is safe. J Trauma. 2011;71:1519-23

Minor Aortic Injury Retrospective, N=47 with BAI 15 (32%) classified MAI (11 intimal flaps, 2

< 1 cm). All treated without intervention and survived with no aortic morbidity

Median 4 day f/u by CT-A (5 resolved, 8 stable) 2 neg. by aortogram

Injury grade by consensus of Presley System Variable management of <1 cm PsAn

Definitions of minor aortic injury in literature Study Definition #Patients with minor TAI Pate et al. [15] Intimal defect causing a 6 (3 developed small aortic diameter luminal compromise of <10% pseudoaneurysms) Malhotra AK, et al. [5] Intima flap <1 cm in size with no 31 (22% of TAI) (G1=23; or minimal MH G2 = 8)) Starnes BW, et al. [12] G1 Absent external contour abnormality:intimal G1=14, G2= 8 (all survived, but flap and/or thrombus <10mm.G2- same as most G2 treated by stent) above >10mm length Paul JS, et al. [13] Intimal flap or pseudoaneurysm <1 cm 15 (32% all TAI) all TAI with or without mediastinal hematoma Mosquera VX, et al. [10] 9 (16% all TAI); no aorta related death 5 yr F/U Azizzadeh, et al. [17] G1 (intimal tear) G2 (intramural hematoma) 10 (14% all TAI) (all G1) G3 (pseudoaneurysm) G4(free rupture) Reisenman PJ, et al. [8] 5 (Grade 1);1 had aortic stent for progression to pseudoaneurysm @ 9 months

Current studies are coalescing towards a definition of minor aortic injury

A minor TAI should permit safe non-interventional management

A prospective study using with a “fixed” anatomical definition of “minor” is required. (Needs multiple institutions)

Study requires a patient group that is consistently managed with predetermined frequency/duration of CT-A follow-up

Conclusions