Safety and feasibility of near-infrared image-guided lymphatic mapping of regional lymph nodes in esophageal cancer.

OBJECTIVE: To assess safety and feasibility of an intraoperative, minimally invasive near-infrared (NIR) image-guided approach to lymphatic mapping in patients with esophageal cancer. METHODS: Although local lymph nodes (LNs) are removed with the esophageal specimen, no techniques are available to identify the regional LNs (separate from the esophagus) during esophagectomy. We hypothesize that NIR imaging can identify regional LNs with the potential to improve staging and guide the extent of lymphadenectomy. Nine of the 10 patients enrolled had resectable esophageal adenocarcinoma and underwent NIR mapping following peritumoral submucosal injection of indocyanine green (ICG) alone or premixed in human serum albumin (ICG:HSA) before resection. NIR imaging was performed in situ and ex vivo. RESULTS: In 6 of the 10 patients, intraoperative NIR imaging demonstrated an NIR signal at all tumors and in 2 to 6 NIR(+) regional LNs. NIR(+) LNs were not identified in 4 patients: 1 patient with occult stage IV disease, for whom further imaging was not performed and thus was excluded from analysis, and 3 patients in whom ICG was used without HSA. Identification of local LNs on the esophagus was obscured by a peritumoral background. Importantly, the pathological status of NIR(+) regional LNs reflected overall regional nodal status. CONCLUSIONS: NIR lymphatic mapping is safe and feasible in patients with esophageal cancer and can identify regional LNs when ICG:HSA is used. Although more work is needed to improve background signals and local LN identification, intraoperative detection of regional NIR(+) LNs allows an in-depth histological analysis of LN basins not commonly scrutinized as part of the specimen and may improve the detection of occult nodal disease.

Predictors of diagnostic success with renal artery duplex ultrasonography.

BACKGROUND: Renal artery duplex ultrasonography (RA-DUS) is commonly used for the evaluation and follow-up of renal artery atherosclerotic disease. In a complete study, renal artery flow is evaluated from the vessel origin to the intraparenchymal branches. The quality of RA-DUS is in part technologist-dependent, but many factors may affect the ability to complete a diagnostic examination. This study evaluated the clinical and technical factors that predict the ability to obtain a complete RA-DUS examination. METHODS: A prospective evaluation of all patients undergoing RA-DUS between July 2008 and February 2009 was performed. Factors such as patient age, gender, body mass index, technologists' years of experience, patient care setting (inpatient vs. outpatient), bedside examination, smoking before the examination, fasting status, and recent abdominal surgery were all recorded. Multivariate logistic regression analysis was performed. A p value of ≤ 0.05 was considered significant. RESULTS: During the study period, 250 patients underwent RA-DUS (mean age: 59.9 ± 17.8 years, 57% [143] female). A total of 87 (35%) examinations were incomplete. This included nondiagnostic examinations which did not exhibit any segment of the renal artery. Factors that were associated with an incomplete examination included technologists' years of experience (OR = 0.92, p = 0.042), bedside examination (OR = 4.17, p = 0.016), and recent abdominal surgery (OR = 3.45, p = 0.047). Body mass index, fasting status, and smoking before the examination did not affect the ability to obtain a complete study. CONCLUSIONS: One-third of the RA-DUS studies were classified as incomplete by the strict criteria used in this prospective study. An experienced ultrasound technologist is more likely to obtain a complete RA-DUS examination. Recent abdominal surgery and bedside examinations were predictive of a limited examination as well. Vascular laboratories should consider these factors when scheduling examinations so as to obtain complete RA-DUS studies, as well as improve the cost-effectiveness of resource utilization.