Durduran, Turgut
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Publication Diffuse Optical Monitoring of Blood Flow and Oxygenation in Human Breast Cancer During Early Stages of Neoadjuvant Chemotherapy(2007-10-19) Zhou, Chao; Choe, Regine; Durduran, Turgut; Shah, Natasha; Yu, Guoqiang; Durkin, Amanda; Hsiang, David; Mehta, Rita; Butler, John; Cerussi, Albert; Tromberg, Bruce J.; Yodh, Arjun G.We combine diffuse optical spectroscopy (DOS) and diffuse correlation spectroscopy (DCS) to noninvasively monitor early hemodynamic response to neoadjuvant chemotherapy in a breast cancer patient. The potential for early treatment monitoring is demonstrated. Within the first week of treatment (day 7) DOS revealed significant changes in tumor/normal contrast compared to pretreatment (day 0) tissue concentrations of deoxyhemoglobin (rctHHbT/N=69±21%), oxyhemoglobin (rctO2HbT/N=73±25%), total hemoglobin (rctTHbT/N=72±17%), and lipid concentration (rctLipidT/N=116±13%). Similarly, DCS found significant changes in tumor/normal blood flow contrast (rBFT/N=75±7% on day 7 with respect to day 0). Our observation suggest the combination of DCS and DOS enhances treatment monitoring compared to either technique alone. The hybrid approach also enables construction of indices reflecting tissue metabolic rate of oxygen, which may provide new insights about therapy mechanisms.Publication Diffuse Optical Monitoring of Hemodynamic Changes in Piglet Brain With Closed Head Injury(2009-05-04) Eucker, Stephanie A; Durduran, Turgut; Yu, Guoqiang; Ralston, Jill; Friess, Stuart H; Ichord, Rebecca N; Margulies, Susan S; Zhou, Chao; Yodh, Arjun G.We used a nonimpact inertial rotational model of a closed head injury in neonatal piglets to simulate the conditions following traumatic brain injury in infants. Diffuse optical techniques, including diffuse reflectance spectroscopy and diffuse correlation spectroscopy (DCS), were used to measure cerebral blood oxygenation and blood flow continuously and noninvasively before injury and up to 6 h after the injury. The DCS measurements of relative cerebral blood flow were validated against the fluorescent microsphere method. A strong linear correlation was observed between the two techniques (R=0.89, p < 0.00001). Injury-induced cerebral hemodynamic changes were quantified, and significant changes were found in oxy- and deoxy-hemoglobin concentrations, total hemoglobin concentration, blood oxygen saturation, and cerebral blood flow after the injury. The diffuse optical measurements were robust and also correlated well with recordings of vital physiological parameters over the 6-h monitoring period, such as mean arterial blood pressure, arterial oxygen saturation, and heart rate. Finally, the diffuse optical techniques demonstrated sensitivity to dynamic physiological events, such as apnea, cardiac arrest, and hypertonic saline infusion. In total, the investigation corraborates potential of the optical methods for bedside monitoring of pediatric and adult human patients in the neurointensive care unit.Publication Validation of Diffuse Correlation Spectroscopic Measurement of Cerebral Blood Flow Using Phase-Encoded Velocity Mapping Magnetic Resonance Imaging(2012-04-17) Buckley, Erin M; Durduran, Turgut; Hance, Dalton; Diaz, Laura K; Pawlowski, Thomas; Putt, Mary E; Lynch, Jennifer; Licht, Daniel J; Wilson, Felice B; Fogel, Mark A; Mesquita, Rickson C; Yodh, Arjun G.Diffuse correlation spectroscopy (DCS) is a novel optical technique that appears to be an excellent tool for assessing cerebral blood flow in a continuous and non-invasive manner at the bedside. We present new clinical validation of the DCS methodology by demonstrating strong agreement between DCS indices of relative cerebral blood flow and indices based on phase-encoded velocity mapping magnetic resonance imaging (VENC MRI) of relative blood flow in the jugular veins and superior vena cava. Data were acquired from 46 children with single ventricle cardiac lesions during a hypercapnia intervention. Significant increases in cerebral blood flow, measured both by DCS and by VENC MRI, as well as significant increases in oxyhemoglobin concentration, and total hemoglobin concentration, were observed during hypercapnia. Comparison of blood flow changes measured by VENC MRI in the jugular veins and by DCS revealed a strong linear relationship, R = 0.88, p < 0.001, slope = 0.91 ± 0.07. Similar correlations were observed between DCS and VENC MRI in the superior vena cava, R = 0.77, slope = 0.99 ± 0.12, p < 0.001. The relationship between VENC MRI in the aorta and DCS, a negative control, was weakly correlated, R = 0.46, slope = 1.77 ± 0.45, p < 0.001.Publication Diffuse optical monitoring of hemodynamic changes in piglet brain with closed head injury(2009-06-04) Eucker, Stephanie A; Durduran, Turgut; Yu, Guoqiang; Ralston, Jill; Friess, Stuart H; Ichord, Rebecca N; Margulies, Susan S; Zhou, Chao; Yodh, Arjun G.We used a nonimpact inertial rotational model of a closed head injury in neonatal piglets to simulate the conditions following traumatic brain injury in infants. Diffuse optical techniques, including diffuse reflectance spectroscopy and diffuse correlation spectroscopy (DCS), were used to measure cerebral blood oxygenation and blood flow continuously and noninvasively before injury and up to 6 h after the injury. The DCS measurements of relative cerebral blood flow were validated against the fluorescent microsphere method. A strong linear correlation was observed between the two techniques (R=0.89, p<0.00001). Injury-induced cerebral hemodynamic changes were quantified, and significant changes were found in oxy- and deoxy-hemoglobin concentrations, total hemoglobin concentration, blood oxygen saturation, and cerebral blood flow after the injury. The diffuse optical measurements were robust and also correlated well with recordings of vital physiological parameters over the 6-h monitoring period, such as mean arterial blood pressure, arterial oxygen saturation, and heart rate. Finally, the diffuse optical techniques demonstrated sensitivity to dynamic physiological events, such as apnea, cardiac arrest, and hypertonic saline infusion. In total, the investigation corraborates potential of the optical methods for bedside monitoring of pediatric and adult human patients in the neurointensive care unit.