Imaging follow-up of endovascular repair of type B aortic dissection with dual-source, dual-energy CT and late delayed-phase scans.
OBJECTIVE
To evaluate the diagnostic performance of dual-energy (DE) computed tomography (CT) after thoracic endovascular aortic repair (TEVAR) of type B dissection, and to investigate the value of late delayed (LD) acquisition in endoleak detection and false lumen patency assessment.


METHODS
Twenty-four patients with TEVAR for type B dissection underwent 53 tripe-phase CT examinations. Single-source unenhanced acquisition was followed by single-source arterial-phase and DE LD phase (300-s delay) imaging. Virtual noncontrast images were generated from DE acquisition. Two blinded radiologists retrospectively evaluated the cases in three reading sessions: session A (triphasic protocol), session B (virtual noncontrast and arterial phase), and session C (virtual noncontrast and arterial and LD phases). Endoleak detection accuracy during sessions B and C compared with session A (reference standard) was investigated. False lumen patency was assessed. Effective radiation dose was calculated.


RESULTS
Session A revealed 37 endoleaks in 30 of 53 studies (56.6%). Session B revealed 31 of the 37 endoleaks, with one false-positive case, 83.8% sensitivity, 95.8% specificity, 79.3% negative predictive value, and 96.9% positive predictive value. Session C correctly depicted all 37 endoleaks, with one false-positive case, 100% sensitivity, 95.8% specificity, 100% negative predictive value, and 97.4% positive predictive value. Underestimation of false lumen patency was found in session B (P = .013). Virtual noncontrast imaging resulted in 17% radiation exposure reduction.


CONCLUSIONS
Virtual noncontrast imaging can replace standard unenhanced images in follow-up after TEVAR of type B dissection, thus reducing radiation dose. Delayed-phase imaging is valuable in low-flow endoleaks detection and false lumen patency assessment.
Department of Radiology and Medical Imaging, University of Virginia Health System, Box 800170, Lee Street, Charlottesville, VA 22908.
Lucia
L
Flors
Department of Radiology and Medical Imaging, University of Virginia Health System, Box 800170, Lee Street, Charlottesville, VA 22908.
Carlos
C
Leiva-Salinas
Department of Radiology and Medical Imaging, University of Virginia Health System, Box 800170, Lee Street, Charlottesville, VA 22908.
Patrick T
PT
Norton
Department of Biostatistics and Epidemiology, University of Virginia Health System, Box 800170, Lee Street, Charlottesville, VA 22908.
James T
JT
Patrie
Department of Radiology and Medical Imaging, University of Virginia Health System, Box 800170, Lee Street, Charlottesville, VA 22908. Electronic address: kdh2n@virginia.edu.
Klaus D
KD
Hagspiel
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000784:Aortic Dissection / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery*; D001014:Aortic Aneurysm / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery*; D001027:Aortography / Q000379:methods; D057867:Endoleak / Q000000981:diagnostic imaging* / Q000209:etiology*; D057510:Endovascular Procedures / Q000009:adverse effects / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome