title: Ultrasound contrast enhancing agents in neurosonology: principles, methods, future possibilities.
abstract: OBJECTIVE
  Ultrasound of the brain supplying arteries is a standard diagnostic procedure in patients with suspected and definite acute and chronic cerebrovascular occlusive disease. Anatomical and pathological limitations led to the development of echocontrast agents which are able to survive pulmonary and capillary transit and improve the echogenicity of the flowing blood.
  
  
  METHODS
  This article reviews present and future applications of echocontrast agents in conjunction with personal experiences.
  
  
  RESULTS
  Currently, echocontrast is used for the differentiation of internal carotid artery occlusion and pseudoocclusion, better delineation of the maximal narrowing in high-grade stenoses, and better visualization of the extracranial vertebral artery and its collaterals. Transcranial applications include the insufficient foraminal or temporal window, assessment of arteriovenous malformations, thrombosis of cerebral veins and sinuses, and intracranial aneurysms. The use of echocontrast can have direct diagnostic and therapeutic consequences. Harmonic imaging, perfusion imaging, stimulated acoustic emission, and drug delivery are possible future domains of the technique.
  
  
  CONCLUSIONS
  Besides the support of conventional neurovascular ultrasound in poor examination conditions due to the patients' anatomy or pathology, echocontrast agents may allow for novel applications in the diagnosis and treatment of cerebrovascular patients.
authors.affiliation: Klinik und Poliklinik für Neurologie der WWU Münster, Germany.
authors.forename: D W
authors.initials: DW
authors.lastname: Droste
authors.forename: M
authors.initials: M
authors.lastname: Kaps
authors.forename: D G
authors.initials: DG
authors.lastname: Navabi
authors.forename: E B
authors.initials: EB
authors.lastname: Ringelstein
mesh_terms: D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging; D002343:Carotid Artery, Internal; D002561:Cerebrovascular Disorders / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003937:Diagnosis, Differential; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*; D014715:Vertebrobasilar Insufficiency / Q000000981:diagnostic imaging
chemical_list: D003287:Contrast Media