Intraoperative identification of esophageal sentinel lymph nodes with near-infrared fluorescence imaging.
OBJECTIVE
In esophageal cancer, selective removal of involved lymph nodes could improve survival and limit complications from extended lymphadenectomy. Mapping with vital blue dyes or technetium Tc-99m often fails to identify intrathoracic sentinel lymph nodes. Our purpose was to develop an intraoperative method for identifying sentinel lymph nodes of the esophagus with high-sensitivity near-infrared fluorescence imaging.


METHODS
Six Yorkshire pigs underwent thoracotomy and received submucosal, esophageal injection of quantum dots, a novel near-infrared fluorescent lymph tracer designed for retention in sentinel lymph nodes. Six additional pigs underwent thoracotomy and received submucosal esophageal injection of CW800 conjugated to human serum albumin, another novel lymph tracer designed for uptake into distant lymph nodes. Finally, 6 pigs received submucosal injection of the fluorophore-conjugated albumin with an endoscopic needle through an esophagascope. These lymph tracers fluoresce in the near-infrared, permitting visualization of migration to sentinel lymph nodes with a custom intraoperative imaging system.


RESULTS
Injection of the near-infrared fluorescent lymph tracers into the esophagus revealed communicating lymph nodes within 5 minutes of injection. In all 6 pigs that received quantum dot injection, only a single sentinel lymph node was identified. Among pigs that received fluorophore-conjugated albumin injection, in 5 of 12 a single sentinel lymph node was revealed, but in 7 of 12 two sentinel lymph nodes were identified. There was no dominant pattern in the appearance of the sentinel lymph nodes either cranial or caudal to the injection site.


CONCLUSIONS
Near-infrared fluorescence imaging of sentinel lymph nodes is a novel and reliable intraoperative technique with the power to assist with identification and resection of esophageal sentinel lymph nodes.
Parungo
Cherie P
CP
Cardiac Surgery Research Laboratory, Brigham & Women's Hospital, Division of Hematology/Oncology, Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
Ohnishi
Shunsuke
S
Kim
Sang-Wook
SW
Kim
Sunjee
S
Laurence
Rita G
RG
Soltesz
Edward G
EG
Chen
Frederick Y
FY
Colson
Yolonda L
YL
Cohn
Lawrence H
LH
Bawendi
Moungi G
MG
Frangioni
John V
JV
D000818:Animals; D004945:Esophagoscopy; D004947:Esophagus / Q000473:pathology*; D005456:Fluorescent Dyes; D007430:Intraoperative Care; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D045663:Quantum Dots; D015203:Reproducibility of Results; D021701:Sentinel Lymph Node Biopsy; D012709:Serum Albumin; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013552:Swine; D013908:Thoracotomy; D013997:Time Factors
D005456:Fluorescent Dyes; D012709:Serum Albumin