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1.  Delta projection imaging on contrast-enhanced ultrasound to quantify tumor microvasculature and perfusion 
Academic radiology  2009;16(1):71-78.
Rationale and Objectives
To assess the delta (Δ) projection image processing technique for visualizing tumor microvessels and for quantifying the area of tissue perfused by them on contrast-enhanced ultrasound images.
Materials and Methods
The Δ-projection algorithm was implemented to quantify perfusion by tracking the running maximum of the difference (Δ) between the contrast-enhanced ultrasound image sequence and a baseline image. Twenty-five mice with subcutaneous K1735 melanomas were imaged first with contrast-enhanced grayscale and then with contrast-enhanced power Doppler (minexCPD) ultrasound. Δ-projection images were reconstructed from the grayscale images, then used to evaluate the evolution of tumor vascularity during the course of contrast enhancement. The extent of vascularity (ratio of the perfused area to the tumor area) for each tumor was determined quantitatively from Δ-projection images and compared with the extent of vascularity determined from contrast-enhanced power Doppler images. Δ-projection and minexCPD measurements were compared using linear regression analysis.
Results
Δ-projection was successfully performed in all 25 cases. The technique allowed dynamic visualization of individual blood vessels as they filled in real-time. Individual tumor blood vessels were distinctly visible during early image enhancement. Later, as an increasing number of blood vessels were filled with the contrast agent, clusters of vessels appeared as regions of perfusion, and identification of individual vessels became difficult. Comparisons were made between the perfused area of tumors in Δ-projections and in minexCPD images. The Δ-projection perfusion measurements correlated linearly with minexCPD.
Conclusion
Δ-projection visualized tumor vessels and enabled quantitative assessment of the tumor area perfused by the contrast agent.
doi:10.1016/j.acra.2008.07.013
PMCID: PMC2644424  PMID: 19064214
Ultrasound contrast agents; power Doppler; angiogenesis; vascular disrupting agent; tumor perfusion
2.  Cerebral hemodynamics in preterm infants during positional intervention measured with diffuse correlation spectroscopy and transcranial Doppler ultrasound 
Optics express  2009;17(15):12571-12581.
Four very low birth weight, very premature infants were monitored during a 12° postural elevation using diffuse correlation spectroscopy (DCS) to measure microvascular cerebral blood flow (CBF) and transcranial Doppler ultrasound (TCD) to measure macrovascular blood flow velocity in the middle cerebral artery. DCS data correlated significantly with peak systolic, end diastolic, and mean velocities measured by TCD (pA =0.036, 0.036, 0.047). Moreover, population averaged TCD and DCS data yielded no significant hemodynamic response to this postural change (p>0.05). We thus demonstrate feasibility of DCS in this population, we show correlation between absolute measures of blood flow from DCS and blood flow velocity from TCD, and we do not detect significant changes in CBF associated with a small postural change (12°) in these patients.
PMCID: PMC2723781  PMID: 19654660

Results 1-2 (2)