Sensitive and Specific Detection of Breast Cancer Lymph Node Metastasis Through Dual-Modality Magnetic Particle Imaging and Fluorescence Molecular Imaging: a Preclinical Evaluation

Purpose: A sensitive and specific imaging method to detect metastatic cancer cells in lymph nodes (LNs) to detect the early-stage breast cancer is urgently needed. The purpose of this study was to investigate a novel breast cancer-targeting and tumour microenvironment ATP-responsive superparamagnetic iron oxide (SPIOs) imaging probe that was developed to detect lymph node metastasis (LNMs) through fluorescence molecular imaging (FMI) and magnetic particle imaging (MPI). The imaging nanoprobe comprised of SPIOs conjugated with breast cancer-targeting peptides (CREKA) and an ATP-responsive DNA aptamer (dsDNA-Cy5.5), abbreviated as SPIOs@A-T. Methods: SPIOs@A-T was synthesised and characterized for its imaging properties, targeting ability and toxicity in vitro. Mice with metastatic lymph node (MLN) of breast cancer were established to evaluate the FMI and MPI imaging strategy in vivo. Healthy mice with normal lymph node (NLN) were used as control group. Histological examination and biosafety evaluation were performed for further assessment. Results: After injection with SPIO@A-T, the obvious high fluorescent intensity and MPI signal were observed in MLN group than those in NLN group. MPI could also complement the limitation of imaging depth from FMI, thus could detect MLN more sensitively. The combination of the imaging strengths of FMI and MPI ensured the detection of breast cancer metastases with high sensitivity and specificity, thereby facilitating the precision differentiation of malignant from benign LNs. Besides, the biosafety evaluation results showed SPIO@A-T had good biocompatibility. Conclusion: Due to the superior properties of tumour-targeting, detection specificity, and biosafety, the SPIOs@A-T imaging probe in combination with FMI and MPI can provide a promising novel method for the early and precise detection of LNMs in clinical practice.

Fluorescence grid analysis for the evaluation of piecemeal surgery in sinonasal inverted papilloma: a proof-of-concept study

Purpose Local recurrence occurs in ~ 19% of sinonasal inverted papilloma (SNIP) surgeries and is strongly associated with incomplete resection. During surgery, it is technically challenging to visualize and resect all SNIP tissue in this anatomically complex area. Proteins that are overexpressed in SNIP, such as vascular endothelial growth factor (VEGF), may serve as a target for fluorescence molecular imaging to guide surgical removal of SNIP. A proof-of-concept study was performed to investigate if the VEGF-targeted near-infrared fluorescent tracer bevacizumab-800CW specifically localizes in SNIP and whether it could be used as a clinical tool to guide SNIP surgery. Methods In five patients diagnosed with SNIP, 10 mg of bevacizumab-800CW was intravenously administered 3 days prior to surgery. Fluorescence molecular imaging was performed in vivo during surgery and ex vivo during the processing of the surgical specimen. Fluorescence signals were correlated with final histopathology and VEGF-A immunohistochemistry. We introduced a fluorescence grid analysis to assess the fluorescence signal in individual tissue fragments, due to the nature of the surgical procedure (i.e., piecemeal resection) allowing the detection of small SNIP residues and location of the tracer ex vivo. Results In all patients, fluorescence signal was detected in vivo during endoscopic SNIP surgery. Using ex vivo fluorescence grid analysis, we were able to correlate bevacizumab-800CW fluorescence of individual tissue fragments with final histopathology. Fluorescence grid analysis showed substantial variability in mean fluorescence intensity (FImean), with SNIP tissue showing a median FImean of 77.54 (IQR 50.47–112.30) compared to 35.99 (IQR 21.48–57.81) in uninvolved tissue (p < 0.0001), although the diagnostic ability was limited with an area under the curve of 0.78. Conclusions A fluorescence grid analysis could serve as a valid method to evaluate fluorescence molecular imaging in piecemeal surgeries. As such, although substantial differences were observed in fluorescence intensities, VEGF-A may not be the ideal target for SNIP surgery. Trial registration NCT03925285.

VEGF-Targeted Multispectral Optoacoustic Tomography and Fluorescence Molecular Imaging in Human Carotid Atherosclerotic Plaques

Vulnerable atherosclerotic carotid plaques are prone to rupture, resulting in ischemic strokes. In contrast to radiological imaging techniques, molecular imaging techniques have the potential to assess plaque vulnerability by visualizing diseases-specific biomarkers. A risk factor for rupture is intra-plaque neovascularization, which is characterized by overexpression of vascular endothelial growth factor-A (VEGF-A). Here, we study if administration of bevacizumab-800CW, a near-infrared tracer targeting VEGF-A, is safe and if molecular assessment of atherosclerotic carotid plaques in vivo is possible using multispectral optoacoustic tomography (MSOT). Healthy volunteers and patients with symptomatic carotid artery stenosis scheduled for carotid artery endarterectomy were imaged with MSOT. Secondly, patients were imaged two days after intravenous administration of 4.5 bevacizumab-800CW. Ex vivo fluorescence molecular imaging of the surgically removed plaque specimen was performed and correlated with histopathology. In this first-in-human MSOT and fluorescence molecular imaging study, we show that administration of 4.5 mg bevacizumab-800CW appeared to be safe in five patients and accumulated in the carotid atherosclerotic plaque. Although we could visualize the carotid bifurcation area in all subjects using MSOT, bevacizumab-800CW-resolved signal could not be detected with MSOT in the patients. Future studies should evaluate tracer safety, higher doses of bevacizumab-800CW or develop dedicated contrast agents for carotid atherosclerotic plaque assessment using MSOT.

VEGF-targeted multispectral optoacoustic tomography and fluorescence molecular imaging in human carotid atherosclerotic plaques

Background: Vulnerable atherosclerotic carotid plaques are prone to rupture resulting in ischemic strokes. Molecular imaging techniques have the potential to assess plaque vulnerability by visualizing molecular markers. Bevacizumab-800CW is a near-infrared fluorescent contrast agent antibody targeting vascular endothelial growth factor-A (VEGF-A). Here, we study if administration of bevacizumab-800CW is safe and can be visualized using multispectral optoacoustic tomography (MSOT) to evaluate atherosclerotic carotid plaques in vivo by visualizing intra-plaque neovascularization.Methods: Healthy volunteers were imaged with MSOT to determine the technical feasibility of human carotid imaging with MSOT. Patients with symptomatic carotid artery stenosis scheduled for carotid artery endarterectomy were intravenously administered with a bolus injection of 4.5 mg bevacizumab-800CW. Before and two days after tracer administration, in vivo non-invasive MSOT was performed. For validation, ex vivo fluorescence molecular imaging of the surgically removed plaque specimen was performed and correlated with histopathology.Results: Administration of 4.5 mg bevacizumab-800CW was safe in five patients. MSOT achieved accurate visualization of the carotid bifurcation area and assessment of the plaque in all five patients. Bevacizumab-800CW-resolved signal could not be detected with MSOT prior to surgery. However, ex vivo analysis of the carotid plaque showed accumulation of bevacizumab-800CW.Conclusions: These first-in-human MSOT and fluorescence molecular imaging results in carotid artery plaques suggest that bevacizumab is a potential tracer for imaging of vulnerable plaques. However, the microdose used here cannot be detected with MSOT. A subsequent phase I dose-finding study is needed to evaluate bevacizumab-800CW in higher doses as a useful optoacoustic imaging agent. Moreover, the development of dedicated optoacoustic contrast agents for signal attenuation of the targeting moiety is advisable for carotid atherosclerotic plaque assessment using MSOT.

Shortwave-infrared (SWIR) fluorescence molecular imaging using indocyanine green–antibody conjugates for the optical diagnostics of cancerous tumours

We present indocyanine green (ICG)-based shortwave-infrared (SWIR) fluorescence molecular imaging for the highly-sensitive optical detection of breast and skin tumours in mice.