1. Suspected Aortic Dissection and Other Aortic Disorders: Multi–Detector Row CT in 373 Cases in the Emergency Setting
Robert G. Hayter, BS, James T. Rhea, MD, Andrew Small, MD, Faranak S. Tafazoli, MD and Robert A. Novelline, MD
Int. 王富弘

2. Introduction Acute life-threatening aortic disorders
Acute aortic dissection, acute aortic intramural hematoma, and acute penetrating aortic ulcer,…
patient's symptoms can vary markedly according to the organ systems affected  clinical diagnosis remains challenging

3. Introduction Aortic dissection
five to 27 cases per million people per year
as many as one-third of cases are not diagnosed
most common aortic disorder requiring surgery
6th and 7th decades of life
3:1 male-to-female predominance,
the most important risk  hypertension and medial degeneration of the aortic wall

5. Introduction Aortic intramural hematoma Penetrating aortic ulceration
lack of detectable intimomedial flap
lack of direct flow communication between the true and false lumina
5%–20% of all acute aortic disorders
Penetrating aortic ulceration
increased risk of progression to acute aortic rupture and other acute aortic disorders
2.3% of cases of suspected aortic dissection ; 52% of aortic intramural hematomas

6. Aortic intramural hematoma

7. Penetrating aortic ulceration

8. Introduction Mortality
A delayed or missed diagnosis of acute aortic dissection, acute aortic intramural hematoma, when untreated :
>1% per hour during the first 24 hours after onset
80% by 2 weeks

9. Introduction Imaging modalities Purpose conventional aortography,
ultrasonography (US)
computed tomography (CT)
magnetic resonance (MR) imaging
Purpose
retrospectively review our experience in using an aortic dissection multi–detector row CT protocol in the emergency setting

10. MATERIALS AND METHODS Patients:
January 1, 2002 ~ June 30, 2003 in ER of MGH
not experienced trauma
suspected aortic aortic disorders underwent multi–detector row CT
all cases had been identified by the authors
Exclude
Inpatients
other clinically suspected problems with associated findings of acute aortic disorder
The cases be inadequate on the basis of the scanning protocol or the final images obtained

11. MATERIALS AND METHODS
aortic dissection multi–detector row CT protocol:
nonenhanced / contrast enhanced; chest, abdominal, and pelvic images
nonenhanced CT
hyperattenuating crescentic hematoma produced by aortic intramural hematomas
aortic intramural hematomas
acute aortic disorder
contrast-enhanced transverse CT
2-minute-delay scanning:
free blood flow between the true and false lumina
coronal and sagittal aortic reformations

12. MATERIALS AND METHODS Definitions Diagnostic tool Positive case
multi–detector row CT, aortography, MR angiography, transesophageal echocardiography (TEE), or transthoracic echocardiography
Positive case
acute aortic dissection,
acute aortic intramural hematoma,
acute penetrating aortic ulcer,
new or enlarging aortic aneurysm
acute aortic rupture

13. MATERIALS AND METHODS Acute aortic disorders
acute aortic dissection,
acute aortic intramural hematoma,
acute penetrating aortic ulcer,
imaging findings criteria +
< 2 weeks of symptoms at the time of scanning, or
changed findings on CT images compared to previous
New or enlarging aortic aneurysm
without associated findings on previously images
thoracic aortic dilatations >= 5 cm in diameter, or abdominal aortic dilatations >= 3 cm
Acute aortic rupture
extravasation of (contrast material / blood) (beyond the adventitia / within the pericardial sac)

14. MATERIALS AND METHODS Definitions
Chronic aortic dissections, aortic intramural hematomas, and penetrating aortic ulcers
more than 2 weeks of symptoms at the time of scanning
Stable aortic dissections, aortic intramural hematomas, and penetrating aortic ulcers
unchanged findings on CT images compared with previously images
or finding of a calcified outer wall in the false lumen
criteria for acute aortic disorder were confirmed by using
"hard" data: surgical and pathologic diagnoses,
or "soft" data: findings at clinical follow-up and any subsequent imaging

15. Data and Statistical Analyses
Images were reviewed independently by two authors (J.T.R., R.A.N.)
accuracy analysis,
multi–detector row CT findings were compared with available aortographic, MR angiographic, TEE, transthoracic echocardiographic, surgical, and pathologic findings; with the discharge diagnoses, clinical follow-up findings
sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the AD multi–detector row CT protocol were calculated by using two-way contingency table analysis
one case interpreted as indeterminate not included

16. Results Type A versus Type B Aortic Disorders TT Type A 71.6y/o^11TT
Type A
71.6y/o^11
M 13
F 4 17
Type B
73.2y/o^16.1
M 10
F 22 32
Acute Aortic A
75.7y/o^9.8
M 22 44
Acute Aortic R
76y/o^9.5
M 7 11

17. Results history of aortic aneurysm and hypertension: now presenting
Ascending thoracic aortic aneurysms
Descending thoracic aortic aneurysms
Abdominal aortic aneurysms TT
Type A 3 2 5 17
Type B 1 9 32
Acute Aortic A 4 10 44
Acute Aortic R 6 11
total 13 12 29 38

18. Results history of aortic diseases: Repaired Ascending thoracic AA/R
Ascending thoracic AA/R
Descending thoracic AA/R
Abdominal AA/R
type A AD repair
Type B AD R
AVR TT
Type A 2 1 17
Type B 6 3 5 32
Acute Aortic A 44
Acute Aortic R 11
total 7
15/22 9 16

19. Results
Multi–Detector Row CT Interpretation of 373 Cases of Suspected Aortic Dissection and Other Aortic Disorders

20. Results
Image exam:
one TEE examination: acute aortic intramural hematoma that was missed at multi–detector row CT
one case interpreted as indeterminate row CT, no acute aortic disorder was found at follow-up TEE
initial imaging modality
addition
multi–detector row CT
367
cardiac US
TEE 6 36
TTE
117
aortography 4 MR 15

21. Results
Statistical Findings

22. Results
Alternative Findings Identified with Aortic Dissection Multi–Detector Row CT Protocol

23. Results
Characteristics of 67 Cases Positive for Acute Aortic Disorder

24. Results IM history: Marfan syndrome Ehlers-Danlos syndrome
Marfan syndrome
Ehlers-Danlos syndrome
Hypertension
Diabetes mellitus
bicuspid or unicommissural aortic valves TT
Type A - 12 1 17
Type B 3 21 2 32
Acute Aortic A 30 4 44
Acute Aortic R 8 11

25. Results Presenting Symptoms Type A Type B Acute AA Acute AR TT
Type A
Type B
Acute AA
Acute AR TT
Chest pain 11 22 9
217
Back pain 4 12 16 1
162
Abd. pain 3 54
Syncope 10
SOB 2 21
Miscellaneous 19
Un-equal BP 5
Tearing chest pain 17 32 44

26. Results BP and EKG Type A Type B Acute AA Acute AR TT SBP<80 1
Type A
Type B
Acute AA
Acute AR TT
SBP<80 1
SBP 81~99 2
SBP 100~139 7 8 14 4
SBP>140 13 15
BP data available 12 23 31
Unequal BP
Nonspecific ST-T 17 22
old Q waves 3 32 44 11

27. Results Radiographic Findings
Aortic calcification, displacement of the aorta, displacement of the mediastinum, and intimal calcification were rare findings
Type A
Type B
Acute AA
Acute AR TT
widened mediastinum 8 4 7
Cardiac silhouette enlargement 6 3
Thoracic aortic ectasia 10
tortuous aorta 5 12 1
Pleural effusion
No wide Med. 16 30
No T A ectasia 14 24 17 32 44 11

28. Results Treatments and Outcomes Type A Type B Acute AA Acute AR TT
Type A
Type B
Acute AA
Acute AR TT
Emergent surgical repair of the aorta 11 6 10
discharged in stable 14 26 41 8
died during hospitalization 2 3
overall mortality rate 4 17 32 44 67

29. Results
Cost Calculations

30. DISCUSSION DeBakey Stanford-Daily system
Type 1 aortic dissection involves both the ascending and the descending aorta.
Type 2 : ascending aorta and extends to the origin of the brachiocephalic artery.
Type 3 : descending aorta, beginning at the origin of the left subclavian artery
Stanford-Daily system
Type A involves the : the ascending aorta and beyond.
Type B : confined to the descending aorta, beginning at the origin of the left subclavian artery
surgery for type A and nonsurgical therapy for type B

31. DISCUSSION

32. DISCUSSION Aortography aortic dissection penetrating aortic ulcers
88% sensitivity, 94% specificity, a 96% positive predictive value, and an 84% negative predictive value
penetrating aortic ulcers
83% sensitive
not be able to depict aortic intramural hematomas or many of the other potential alternative findings
expensive, time-consuming, and associated with higher morbidity

33. DISCUSSION CT
~100% sensitivity and specificity for detection of aortic dissection and aortic intramural hematoma
Other published data show CT to have 65% sensitivity for detection of penetrating aortic ulcers
aortic dissection CT protocols are more than adequately reliable for the detection of true aortic dissection and other aortic disorders

34. DISCUSSION US techniques transthoracic echocardiography TEE
sensitivity for detection of type A (60%–80%) and type B (50%) aortic dissections and 90% specificity for detection of both types
TEE
requires esophageal intubation
sensitivity of 97%–99%, specificity of 99%–100% in the detection of aortic dissection
sensitivity of 90%–100% and a specificity of 91%–100% for detection of aortic intramural hematomas
sensitivity of 61%–83% for detection of penetrating aortic ulcers
lead to increased systolic blood pressure acute aortic rupture

35. DISCUSSION MR
sensitivity (95%–100%) specificity (94%–98%) for detection of aortic dissection
sensitivity of 100% for detection of aortic intramural hematoma
sensitivity of 86% for detection of penetrating aortic ulcer
requires approximately 30 minutes
more expensive than CT
not readily available in many emergency departments

36. DISCUSSION CT—is now the primary imaging modality
Exceptions to this standard arise when patient instability, poor renal function, and/or allergy to iodinated contrast material
too unstable  TEE (need skillful in ~ 5min)
impaired renal function or iodinated contrast material allergy  MR

37. DISCUSSION limitations of the investigation
limited application of the data to other populations
lack of a clear definition of what may increased use of the aortic dissection multi–detector row CT protocol
lack of a clear definition retrospective design

38. positivity rate of 18%, when compared with the accepted positivity rate of 1% for detection of traumatic aortic injury with CT, suggests that the described aortic dissection multi–detector row CT protocol is not overused
no reliable data derived from the presenting symptoms and signs, radiographic findings, or electrocardiographic findings to aid in the further screening of patients
physician must keep a high clinical index of suspicion for aortic aortic disorders because we have CT