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SU‐GG‐J‐39: Assessment of Early Vascular Response to Anti‐Angiogenic Therapy in a Murine Model Using Acoustic Radiation‐Mediated Multimodal Optical Spectroscopy
Author(s) -
Yan K,
Wachsberger P,
Liu Y,
Marrero N,
Hu Y,
Yu Y
Publication year - 2008
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2961597
Subject(s) - ultrasound , medicine , biomedical engineering , materials science , pathology , radiology
Purpose: To investigate the efficacy of using acoustic radiation force (ARF) combined with optical spectroscopy to assess early effects of anti‐angiogenic therapy on changes in oxy‐hemoglobin saturation in a human glioblastoma xenograft model. Method and Materials: Pilot experiments were carried out with nude mice bearing human U87 glioblastoma xenografts. Acoustic field intensities were generated using a focused transducer operating below the FDA diagnostic ultrasound limits. During each experiment, ultrasound was administered for 5‐second bursts, with 55‐second relaxation periods between bursts and a total of five bursts per data collection per tumor position. A broadband light source was used for tissue illumination; diffuse reflectance spectra were collected from the tumor using an optical probe and a room‐temperature spectrometer. Baseline measurements were taken on Day‐0 before injecting a VEGF blocker drug to the mice. After drug administration, multimodal ARF‐optical measurements were taken each day at the same locations of each tumor for 4 consecutive days (Day1–4). Results: Preliminary results revealed that the mean values of the spectroscopic signals reflecting oxy‐ vs. deoxy‐hemoglobin concentrations increased over a period of 4 days, which suggest an increase in oxygen level over time during treatment with the VEGF blocker in the tumor tissue. On Day‐2, post‐ischemic reactive hyperemia was highly significant, a phenomenon previously observed in normal vasculature only, which suggests that the drug effects on blood vessel normalization were most significant at this treatment time‐point. On Day‐4, the multimodal ARF‐optical signal starts to display the behavior of flow stasis in benign vessels, which corresponds to the expected schedule of the drug on vessel normalization. Conclusion: This is the first pilot study to demonstrate the feasibility of using multimodal imaging to monitor and assess early changes of blood vessel normalization due to anti‐angiogenic therapy. Ongoing experiments are being carried out for further mechanistic investigation.