Aortic dissection: MRI was better than echocardiography at diagnosing dissection.

Clinical bottom line (level 1b)

  1. About two thirds of patients with a suspected aortic dissection had one.
  2. MRI diagnosed and excluded aortic dissection.
  3. Both transthoracic and transoesophageal echocardiography made aortic dissection more likely if positive, but could not safely exclude it.
Nienaber et al: Circulation 1992; 85: 434-447
Expires December 2004

The study

Setting: emergency department and intensive care and radiologic units in a university-affiliated hospital, Germany

53 patients (aged range 20 to 76 years; mean 52, 66% male) suspected aortic dissection

Excluded if
  • unstable angina, myocardial infarction, pulmonary embolism or pneumothorax



    • Independent blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
    Reference standard:
    • surgery or autopsy or contrast angiography (+/- CT scan), or follow-up for 16 months (+/- 5 months). Angiography positive if intimal flap or double lumen in aorta seen
    Diagnostic test:
    • transthoracic echocardiography. Positive if presence of two vascular lumens separated by an intimal flap, or central dislocation of intimal calcification
    • 2-D TEE including colours Doppler flow mapping and pulsed-wave Doppler echograms using a wide angle, phased array transducer. The oesophageal probe was rotated, tilted and gradually withdrawn to allow mapping of the descending and ascending aorta and arch. Examination required 5-14 minutes. Patients were starved for one hour if stable. Positive if presence of two vascular lumens separated by an intimal flap, or central dislocation of intimal calcification.
    • transverse MRI scans in 8-10 mm slices over the aorta of the supine patient included a 40 cm field. A whole body, high-field strength scanner was used. Examination required 15-65 minutes, which included cine-MRI in 43 patients. Positive if two lumens separated by intimal flap.

    The evidence

    pre-test probability of aortic dissection: 58%, (95% CI: 45% to 72%)

    diagnostic test number of patients sensitivity for
    aortic dissection
    (95% CI)    		 specificity for
    aortic dissection
    (95% CI)    		 LR+ LR-
    TTE: any dissection 82.7%
    (% to %)     		63.1%
    (% to %)     		2.7 0.27
    TTE: type A 85.0%
    (% to %)     		78.1%
    (% to %)     		3.9 0.19
    TTE: type B 55.5%
    (% to %)     		100%
    (% to %)     		infinity 0.44
    total 31


    diagnostic test number of patients sensitivity for
    aortic dissection
    (95% CI)    		 specificity for
    aortic dissection
    (95% CI)    		 LR+ LR-
    TEE: any dissection 100%
    (% to %)     		68.2%
    (% to %)     		3.1 0.0
    TEE: type A 100%
    (% to %)     		78.8%
    (% to %)     		4.7 0.0
    TEE: type B 90.9%
    (% to %)     		97.6%
    (% to %)     		38 0.10
    total 31


    diagnostic test number of patients sensitivity for
    aortic dissection
    (95% CI)    		 specificity for
    aortic dissection
    (95% CI)    		 LR+ LR-
    MRI: any dissection 100%
    (% to %)     		100%
    (% to %)     		infinity 0.0
    MRI: type A 100%
    (% to %)     		100%
    (% to %)     		infinity 0.0
    MRI: type B 100%
    (% to %)     		100%
    (% to %)     		infinity 0.0
    total 31


    diagnostic test number of patients sensitivity for
    aortic dissection
    (95% CI)    		 specificity for
    aortic dissection
    (95% CI)    		 LR+ LR-
    aortic regurgitation: TTE 100%
    (% to %)     		87.5%
    (% to %)     		8.0 0.0
    aortic regurgitation: TEE 100%
    (% to %)     		87.5%
    (% to %)     		8.0 0.0
    aortic regurgitation: MRI 84.6%
    (% to %)     		100%
    (% to %)     		infinity 0.15
    total 31


    diagnostic test number of patients sensitivity for
    aortic dissection
    (95% CI)    		 specificity for
    aortic dissection
    (95% CI)    		 LR+ LR-
    pleural effusion: TTE 85.7%
    (% to %)     		100%
    (% to %)     		infinity 0.14
    pleural effusion: TEE 100%
    (% to %)     		100%
    (% to %)     		infinity 0.0
    pleural effusion: MRI 100%
    (% to %)     		100%
    (% to %)     		infinity 0.0
    total 31

    • dissection type A:
      • no. of patients: 20
      • subacute dissection: 5
      • deaths: 4
      • surgery: 16
      • medical therapy: 0
    • dissection type B:
      • no. of patients: 11
      • subacute dissection: 5
      • deaths: 3
      • surgery: 5
      • medical therapy: 3

    Comments

    1. MRI is the best test, but it takes longer than echo.

    Citation

    1. Nienaber CA, Spielmann RP, von Kodolitsch Y, et al: Diagnosis of thoracic aortic dissection: magnetic resonance imaging versus transesophageal echocardiography. Circulation 1992; 85: 434-447
    Search Terms: aortic dissection in Best Evidence
    Contributor: Chris Ball and Clare Wotton, December 2000
    Reviewer:

    Clinical Question.
    Patient suspected aortic dissection
    Intervention or Exposure MRI, TTE, TEE
    Outcome diagnosis