title: MEMS-based handheld fourier domain Doppler optical coherence tomography for intraoperative microvascular anastomosis imaging.
abstract: OBJECTIVE
  To demonstrate the feasibility of a miniature handheld optical coherence tomography (OCT) imager for real time intraoperative vascular patency evaluation in the setting of super-microsurgical vessel anastomosis.
  
  
  METHODS
  A novel handheld imager Fourier domain Doppler optical coherence tomography based on a 1.3-µm central wavelength swept source for extravascular imaging was developed. The imager was minimized through the adoption of a 2.4-mm diameter microelectromechanical systems (MEMS) scanning mirror, additionally a 12.7-mm diameter lens system was designed and combined with the MEMS mirror to achieve a small form factor that optimize functionality as a handheld extravascular OCT imager. To evaluate in-vivo applicability, super-microsurgical vessel anastomosis was performed in a mouse femoral vessel cut and repair model employing conventional interrupted suture technique as well as a novel non-suture cuff technique. Vascular anastomosis patency after clinically successful repair was evaluated using the novel handheld OCT imager.
  
  
  RESULTS
  With an adjustable lateral image field of view up to 1.5 mm by 1.5 mm, high-resolution simultaneous structural and flow imaging of the blood vessels were successfully acquired for BALB/C mouse after orthotopic hind limb transplantation using a non-suture cuff technique and BALB/C mouse after femoral artery anastomosis using a suture technique. We experimentally quantify the axial and lateral resolution of the OCT to be 12.6 µm in air and 17.5 µm respectively. The OCT has a sensitivity of 84 dB and sensitivity roll-off of 5.7 dB/mm over an imaging range of 5 mm. Imaging with a frame rate of 36 Hz for an image size of 1000(lateral)×512(axial) pixels using a 50,000 A-lines per second swept source was achieved. Quantitative vessel lumen patency, lumen narrowing and thrombosis analysis were performed based on acquired structure and Doppler images.
  
  
  CONCLUSIONS
  A miniature handheld OCT imager that can be used for intraoperative evaluation of microvascular anastomosis was successfully demonstrated.
authors.affiliation: Department of Electrical and Computer Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland, 21218, United States of America.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Plastic and Reconstructive Surgery, Vascularized Composite Allotransplantation (VCA) Laboratory, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 749D, Baltimore, Maryland, 21205, United States of America.
authors.forename: Georg J
authors.initials: GJ
authors.lastname: Furtmüller
authors.affiliation: Department of Plastic and Reconstructive Surgery, Vascularized Composite Allotransplantation (VCA) Laboratory, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 749D, Baltimore, Maryland, 21205, United States of America; Department of Hand Surgery, Beijing Jishuitan Hospital, 31 Xinjiekou East Street, Xicheng District, Beijing, 10035, China.
authors.forename: Dedi
authors.initials: D
authors.lastname: Tong
authors.affiliation: Department of Plastic and Reconstructive Surgery, Vascularized Composite Allotransplantation (VCA) Laboratory, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 749D, Baltimore, Maryland, 21205, United States of America; Peking Union Medical College and Chinese Academy of Medical Sciences, Department of Plastic and Reconstructive Surgery, Plastic Surgery Hospital, 3 Ba-Da-Chu Road, Shijingshan District, Beijing, 10044, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhu
authors.affiliation: Department of Plastic and Reconstructive Surgery, Vascularized Composite Allotransplantation (VCA) Laboratory, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 749D, Baltimore, Maryland, 21205, United States of America.
authors.forename: W P Andrew
authors.initials: WP
authors.lastname: Lee
authors.affiliation: Department of Plastic and Reconstructive Surgery, Vascularized Composite Allotransplantation (VCA) Laboratory, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 749D, Baltimore, Maryland, 21205, United States of America.
authors.forename: Gerald
authors.initials: G
authors.lastname: Brandacher
authors.affiliation: Department of Electrical and Computer Engineering, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland, 21218, United States of America.
authors.forename: Jin U
authors.initials: JU
authors.lastname: Kang
mesh_terms: D000818:Animals; D001163:Arteriovenous Anastomosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003952:Diagnostic Imaging; D006801:Humans; D021621:Imaging, Three-Dimensional; D051379:Mice; D055617:Micro-Electrical-Mechanical Systems; D055806:Microvessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011859:Radiography; D041623:Tomography, Optical Coherence