title: Versatile utilization of real-time intraoperative contrast-enhanced ultrasound in cranial neurosurgery: technical note and retrospective case series.
abstract: OBJECTIVE
  Intraoperative contrast-enhanced ultrasound (iCEUS) offers dynamic imaging and provides functional data in real time. However, no standardized protocols or validated quantitative data exist to guide its routine use in neurosurgery. The authors aimed to provide further clinical data on the versatile application of iCEUS through a technical note and illustrative case series.
  
  
  METHODS
  Five patients undergoing craniotomies for suspected tumors were included. iCEUS was performed using a contrast agent composed of lipid shell microspheres enclosing perflutren (octafluoropropane) gas. Perfusion data were acquired through a time-intensity curve analysis protocol obtained using iCEUS prior to biopsy and/or resection of all lesions.
  
  
  RESULTS
  Three primary tumors (gemistocytic astrocytoma, glioblastoma multiforme, and meningioma), 1 metastatic lesion (melanoma), and 1 tumefactive demyelinating lesion (multiple sclerosis) were assessed using real-time iCEUS. No intraoperative complications occurred following multiple administrations of contrast agent in all cases. In all neoplastic cases, iCEUS replicated enhancement patterns observed on preoperative Gd-enhanced MRI, facilitated safe tumor debulking by differentiating neoplastic tissue from normal brain parenchyma, and helped identify arterial feeders and draining veins in and around the surgical cavity. Intraoperative CEUS was also useful in guiding a successful intraoperative needle biopsy of a cerebellar tumefactive demyelinating lesion obtained during real-time perfusion analysis.
  
  
  CONCLUSIONS
  Intraoperative CEUS has potential for safe, real-time, dynamic contrast-based imaging for routine use in neurooncological surgery and image-guided biopsy. Intraoperative CEUS eliminates the effect of anatomical distortions associated with standard neuronavigation and provides quantitative perfusion data in real time, which may hold major implications for intraoperative diagnosis, tissue differentiation, and quantification of extent of resection. Further prospective studies will help standardize the role of iCEUS in neurosurgery.
authors.affiliation: Departments of 1 Radiology and.
authors.forename: Ilya
authors.initials: I
authors.lastname: Lekht
authors.affiliation: Departments of 1 Radiology and.
authors.forename: Noah
authors.initials: N
authors.lastname: Brauner
authors.affiliation: Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California.
authors.forename: Joshua
authors.initials: J
authors.lastname: Bakhsheshian
authors.affiliation: Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California.
authors.forename: Ki-Eun
authors.initials: KE
authors.lastname: Chang
authors.affiliation: Departments of 1 Radiology and.
authors.forename: Mittul
authors.initials: M
authors.lastname: Gulati
authors.affiliation: Departments of 1 Radiology and.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Shiroishi
authors.affiliation: Departments of 1 Radiology and.
authors.forename: Edward G
authors.initials: EG
authors.lastname: Grant
authors.affiliation: Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California.
authors.forename: Eisha
authors.initials: E
authors.lastname: Christian
authors.affiliation: Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Zada
mesh_terms: D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D003199:Computer Systems / Q000706:statistics & numerical data*; D003287:Contrast Media; D003399:Craniotomy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods / Q000706:statistics & numerical data*; D019635:Neurosurgical Procedures / Q000379:methods; D012189:Retrospective Studies; D018084:Ultrasonography, Interventional / Q000379:methods / Q000706:statistics & numerical data*
chemical_list: D003287:Contrast Media
keywords: FDA = Food and Drug Administration; PI = peak intensity; ROI = region of interest; TIC = time-intensity curve; TTP = time to peak; USCA = ultrasound contrast agent; contrast; dynamic imaging; iCEUS = intraoperative contrast-enhanced ultrasound; iMRI = intraoperative MRI; iUS = intraoperative ultrasound; microbubbles; perfusion; sonography; ultrasound