Nuclear Spin-Lattice and Viscoelastic Relaxation in Selected Hydrocarbon Liquids

Cutnell, John D.; Stejskal, E. O.

doi:10.1063/1.1677175

Cited by 5 publications

(4 citation statements)

References 32 publications

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“…The simulation used a Newtonian model with kinematic viscosity 𝜈 = 3.3 × 10 −6 m 2 ∕s and density 𝜌 = 1060 kg/m 3 for blood. 29,30 For the contrast agent, a concentration of 300 mgI/mL was assumed with 𝜈 = 7.36 × 10 −6 m 2 ∕s and a measured density 𝜌 = 1340 kg/m 3 . 31 In the initial state, the tube was assumed to be completely filled with blood (no contrast).…”

Section: Computational Fluid Dynamics (Cfd) Simulationmentioning

confidence: 99%

Spatiotemporal frequency domain analysis for blood velocity measurement during embolization procedures

Wagner,

Whitehead,

Periyasamy

et al. 2023

Medical Physics

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BackgroundCurrently, determining procedural endpoints and treatment efficacy of vascular interventions is largely qualitative and relies on subjective visual assessment of digital subtraction angiography (DSA) images leading to large interobserver variabilities and poor reproducibility. Quantitative metrics such as the residual blood velocity in embolized vessel branches could help establish objective and reproducible endpoints. Recently, velocity quantification techniques based on a contrast enhanced X‐ray sequence such as qDSA and 4D DSA have been proposed. These techniques must be robust, and, to avoid radiation dose concerns, they should be compatible with low dose per frame image acquisition.PurposeTo develop and evaluate a technique for robust blood velocity quantification from low dose contrast enhanced X‐ray image sequences that leverages the oscillating signal created by pulsatile blood flow.MethodsThe proposed spatiotemporal frequency domain (STF) approach quantifies velocities from time attenuation maps (TAMs) representing the oscillating signal over time for all points along a vessel centerline. Due to the time it takes a contrast bolus to travel along the vessel centerline, the resulting TAM resembles a sheared sine wave. The shear angle is related to the velocity and can be determined in the spatiotemporal frequency domain after applying the 2D Fourier transform to the TAM. The approach was evaluated in a straight tube phantom using three different radiation dose levels and compared to ultrasound transit‐time‐based measurements. The STF velocity results were also compared to previously published approaches for the measurement of blood velocity from contrast enhanced X‐ray sequences including shifted least squared (SLS) and phase shift (PHS). Additionally, an in vivo porcine study (n = 8) was performed where increasing amounts of embolic particles were injected into a hepatic or splenic artery with intermittent velocity measurements after each injection to monitor the resulting reduction in velocity.ResultsAt the lowest evaluated dose level (average air kerma rate 1.3 mGy/s at the interventional reference point), the Pearson correlation between ultrasound and STF velocity measurements was 99%. This was significantly higher () than corresponding correlation results between ultrasound and the previously published SLS and PHS approaches (91 and 93%, respectively). In the in vivo study, a reduction in velocity was observed in 85.7% of cases after injection of 1 mL, 96.4% after 3 mL, and 100.0% after 4 mL of embolic particles.ConclusionsThe results show good agreement of the spatiotemporal frequency domain approach with ultrasound even in low dose per frame image sequences. Additionally, the in vivo study demonstrates the ability to monitor the physiological changes due to embolization. This could provide quantitative metrics during vascular procedures to establish objective and reproducible endpoints.

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Section: Computational Fluid Dynamics (Cfd) Simulationmentioning

confidence: 99%

Spatiotemporal frequency domain analysis for blood velocity measurement during embolization procedures

Wagner,

Whitehead,

Periyasamy

et al. 2023

Medical Physics

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“…Even in the absence of such an assignment, the availability of the correlation time over a wider range of temperatures facilities comparisons with potentially important variables such as viscosity. 4. Temperature Dependence of Nmr Correlation Times and Viscosity.…”

Section: I03/t(v)mentioning

confidence: 99%

“…Cutnell and Stejskal4 have studied 6,6,11,11-tetramethylhexadecane, squalane, and squalene as pure liquids. Some of the above mentioned compounds have also been studied in the solid state by Anderson and Slichter,5 Douglass and Jones,6 and van Putte.7 These solid-state studies encompass the normal paraffins with carbon chain lengths between 4 and 94.…”

Section: Introductionmentioning

confidence: 99%

Nuclear spin-lattice relaxation in long chain viscous hydrocarbons

Cutnell¹,

Schisla²,

Hammann³

1973

J. Phys. Chem.

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“…Its density was assumed to be 1,010 kg/m 3 , between the densities of water and blood plasma 103 . Likewise, the dynamic viscosity was assumed to be 1.10 cP to lie between those of water and blood plasma 104 .…”

Section: Shear Stress Calculationsmentioning

confidence: 99%

Development of a physiologic ex vivo vessel perfusion system.

Buller

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system integrated with a mock adult circulatory system was design to study the impact of VAD-generated flow patterns on vascular function. Methods:The benefits of a mock circulatory loop and an ex vivo perfusion system were combined by designing and integrating a vessel perfusion chamber to an adult-sized mock circulatory loop as a parallel flow branch distal to VAD outflow. Testing was conducted using a mock over several physiologic conditions (normal, heart failure, and hypertension) and at various levels of VAD flow. The system was integrated into an incubator to allow for control of pH and temperature in future studies and fitted with a vessel for feasibility testing. Data was collected using a custom Labview program and analyzed using the HEART program, an automated beat-to-beat cardiovascular analysis program based in The system was found to be sufficient for future testing with bovine carotid arteries and extended perfusion times (>24 hours). Conclusions:This study resulted in an ex vivo vessel perfusion system that can successfully expose bovine carotid arteries to physiologic and VAD-specific hemodynamic waveforms. The ability to combine the mock ventricle with clinically implanted VADs makes this system both unique and clinically relevant for studying the effects of continuous versus pulsatile flow on the peripheral vasculature.

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Nuclear Spin-Lattice and Viscoelastic Relaxation in Selected Hydrocarbon Liquids

Cited by 5 publications

References 32 publications

Spatiotemporal frequency domain analysis for blood velocity measurement during embolization procedures

Spatiotemporal frequency domain analysis for blood velocity measurement during embolization procedures

Nuclear spin-lattice relaxation in long chain viscous hydrocarbons

Development of a physiologic ex vivo vessel perfusion system.

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