title: The role of contrast-enhanced ultrasound (CEUS) in visualizing atherosclerotic carotid plaque vulnerability: which injection protocol? Which scanning technique?
abstract: OBJECTIVE
  To correlate the degree of plaque vulnerability as determined by contrast-enhanced ultrasound (CEUS) with histological findings. Secondary objectives were to optimize the CEUS acquisition technique and image evaluation methods.
  
  
  METHODS
  Fifty consecutive patients, either symptomatic and asymptomatic referring to our department in order to perform carotid endarterectomy (TEA), were enrolled. Each patient provided informed consent before undergoing CEUS. Ultrasound examination was performed using high-frequency (8-14 MHz) linear probe and a non-linear pulse inversion technique (mechanical index: 0.09-1.3). A double contrast media injection (Sonovue, 2 mL and 4 mL; Bracco, Italy) was performed. Two videotapes were recorded for every injection: early "dynamic" phase and late "flash" phase, performed with 6 high mechanical index impulses. Movies were quantitatively and qualitatively evaluated. Qualitative and quantitative evaluation were statistically compared to immunohistological diagnosis of vulnerable plaque, considered as gold standard.
  
  
  RESULTS
  Qualitative CEUS evaluation obtained high statistical results when compared to immunohistological results, with values of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of 94%, 68%, 87%, 85% and 86%, respectively, which became higher if considering only asymptomatic patient, with a NPV of 91%. Nevertheless, quantitative software evaluation proved less effective and could not reach similar results.
  
  
  CONCLUSIONS
  Carotid plaque enhancement assessed with CEUS well correlates with histological assessment of plaque instability. CEUS may provide valuable information for plaque risk stratification and may play a role in the indication to treatment of patients with carotid stenoses, particularly in asymptomatic population.
authors.affiliation: Department of Bioimaging and Radiological Sciences, Institute of Radiology, "A. Gemelli" Hospital-Catholic University, L.go A Gemelli 8, 00168 Rome, Italy. Electronic address: roberto.iezzi@rm.unicatt.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: Iezzi
authors.affiliation: Institute of Pathology, "A. Gemelli" Hospital-Catholic University, L.go A Gemelli 8, 00168, Rome, Italy.
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Petrone
authors.affiliation: Department of Vascular Surgery, "A. Gemelli" Hospital-Catholic University, L.go A Gemelli 8, 00168 Rome, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Ferrante
authors.affiliation: Institute of Pathology, "A. Gemelli" Hospital-Catholic University, L.go A Gemelli 8, 00168, Rome, Italy.
authors.forename: Libero
authors.initials: L
authors.lastname: Lauriola
authors.affiliation: Department of Vascular Surgery, "A. Gemelli" Hospital-Catholic University, L.go A Gemelli 8, 00168 Rome, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Vincenzoni
authors.affiliation: Department of Bioimaging and Radiological Sciences, Institute of Radiology, "A. Gemelli" Hospital-Catholic University, L.go A Gemelli 8, 00168 Rome, Italy.
authors.forename: Michele Fabio
authors.initials: MF
authors.lastname: la Torre
authors.affiliation: Department of Vascular Surgery, "A. Gemelli" Hospital-Catholic University, L.go A Gemelli 8, 00168 Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Snider
authors.affiliation: Institute of Pathology, "A. Gemelli" Hospital-Catholic University, L.go A Gemelli 8, 00168, Rome, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Rindi
authors.affiliation: Department of Bioimaging and Radiological Sciences, Institute of Radiology, "A. Gemelli" Hospital-Catholic University, L.go A Gemelli 8, 00168 Rome, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Bonomo
mesh_terms: D000368:Aged; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery; D003287:Contrast Media; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D007267:Injections; D008297:Male; D008875:Middle Aged; D010743:Phospholipids; D058226:Plaque, Atherosclerotic / Q000601:surgery*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013459:Sulfur Hexafluoride; D014463:Ultrasonography / Q000379:methods
chemical_list: D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride
keywords: CEUS; Carotid plaque; Dynamic imaging; Late-phase imaging; Vulnerable plaque