Detection of postoperative granulation tissue with an ICG-enhanced integrated OI-/X-ray System

Department of Radiology, University of California, San Francisco, USA.
Journal of Translational Medicine (Impact Factor: 3.93). 12/2008; 6(1):73. DOI: 10.1186/1479-5876-6-73
Source: PubMed


The development of postoperative granulation tissue is one of the main postoperative risks after lumbar spine surgery. This granulation tissue may lead to persistent or new clinical symptoms or complicate a follow up surgery. A sensitive non-invasive imaging technique, that could diagnose this granulation tissue at the bedside, would help to develop appropriate treatments. Thus, the purpose of this study was to establish a fast and economic imaging tool for the diagnosis of granulation tissue after lumbar spine surgery, using a new integrated Optical Imaging (OI)/X-ray imaging system and the FDA-approved fluorescent contrast agent Indocyanine Green (ICG).
12 male Sprague Dawley rats underwent intervertebral disk surgery. Imaging of the operated lumbar spine was done with the integrated OI/X-ray system at 7 and 14 days after surgery. 6 rats served as non-operated controls. OI/X-ray scans of all rats were acquired before and after intravenous injection of the FDA-approved fluorescent dye Indocyanine Green (ICG) at a dose of 1 mg/kg or 10 mg/kg. The fluorescence signal of the paravertebral soft tissues was compared between different groups of rats using Wilcoxon-tests. Lumbar spines and paravertebral soft tissues were further processed with histopathology.
In both dose groups, ICG provided a significant enhancement of soft tissue in the area of surgery, which corresponded with granulation tissue on histopathology. The peak and time interval of fluorescence enhancement was significantly higher using 10 mg/kg dose of ICG compared to the 1 mg/kg ICG dose. The levels of significance were p < 0.05. Fusion of OI data with X-rays allowed an accurate anatomical localization of the enhancing granulation tissue.
ICG-enhanced OI is a suitable technique to diagnose granulation tissue after lumbar spine surgery. This new imaging technique may be clinically applicable for postoperative treatment monitoring. It could be also used to evaluate the effect of anti-inflammatory drugs and may even allow evaluations at the bedside with new hand-held OI scanners.

Download full-text


Available from: Sidhartha Tavri
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate a combined indocyanine green-enhanced optical imaging/radiography system for the detection of arthritic joints in a rat model of antigen-induced arthritis. Arthritis of the knee and ankle joints was induced in 6 Harlan rats, using peptidoglycan-polysaccharide polymers. Three rats served as untreated controls. Optical imaging of the knee and ankle joints was done with an integrated optical imaging/radiography system before and up to 24 hours following intravenous injection of 10 mg/kg indocyanine green. The fluorescence signal intensities of arthritic and normal joints were compared for significant differences, using generalized estimating equation models. Specimens of knee and ankle joints were further processed and evaluated by histology. Immediately after administration, indocyanine green provided a significant increase in the fluorescence signal of arthritic joints compared with baseline values (P < 0.05). The fluorescence signal of arthritic joints was significantly higher compared with that of nonarthritic control joints at 1-720 minutes after intravenous injection (P < 0.05). Fusion of indocyanine green-enhanced optical imaging and radiography allowed for anatomic coregistration of the inflamed tissue with the associated joint. Hematoxylin and eosin staining confirmed marked synovial inflammation of arthritic joints and the absence of inflammation in control joints. Indocyanine green-enhanced optical imaging is a clinically applicable tool for detection of arthritic tissue. Using relatively high doses of indocyanine green, long-term enhanced fluorescence of arthritic joints can be achieved. This may facilitate simultaneous evaluations of multiple joints in a clinical setting. Fusion of indocyanine green-enhanced optical imaging scans with radiography increases anatomic resolution.
    Full-text · Article · Aug 2010 · Arthritis & Rheumatology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cancer immunotherapies can be guided by cellular imaging techniques, which can identify the presence or absence of immune cell accumulation in the tumor tissue in vivo and in real time. This review summarizes various new and evolving imaging techniques employed for tracking and monitoring of adoptive natural killer cell immunotherapies.
    Full-text · Article · Aug 2010 · Cancer Research
  • [Show abstract] [Hide abstract]
    ABSTRACT: Indocyanine green (ICG) fluorescence videography has been recently applied to the neurosurgical field, mostly in the management of cerebral aneurysms, but has had limited description in the subspecialty of spine or oncological neurosurgery. We describe a novel application of this previously defined surgical tool to assist in the resection of a residual spinal cord hemangioblastoma. Our patient is a 49-year-old woman with a residual symptomatic cervical hemangioblastoma that was previously embolized and resected at another institution. After initial symptomatic improvement, she returned with progressive symptoms, increasing radiographic spinal cord edema, and a residual lesion at the level of C1. We resected the remaining tumor with the adjuvant use of ICG fluorescence videography. Intraoperative injection of ICG clearly identified a component of the tumor underlying adhesive, opaque arachnoid that was not visualized by direct microscopy. Immediate postresection ICG videography suggested a complete resection was achieved which was later corroborated by postoperative magnetic resonance imaging. The adjuvant use of ICG videography is a useful surgical tool that permits greater visualization of the complete extent of the lesion, particularly in managing recurrent or residual lesions obscured by adhesions.
    No preview · Article · Sep 2010 · Neurosurgery
Show more