Age-dependent efficiency of magnetic drug targeting in young and old patient-specific aortic models.

Older patients consistently exhibited slightly higher capture efficiency (CE) than younger patients across all rheological models tested.

• The trend was driven by reduced flow velocity, enlarged aortic lumen, and lower wall shear stress in older patients
• These factors collectively prolonged nanoparticle residence time and reduced hydrodynamic drag opposing magnetic capture
• The age-dependent difference was observed across Carreau, Power-law, and Casson-Papanastasiou rheological models
• At 0.5 T using the Carreau model, CE was 2.4% (old) vs. 2.1% (young); at 1.25 T, CE was 7.3% (old) vs. 6.6% (young)

Capture efficiency increased with both particle size and magnetic field intensity across all rheological models.

• Magnetic field strengths ranged from 0.5 to 1.5 T in the simulations
• Under a 1.5 T field using the Carreau model, CE reached 8.7% for 1000 nm particles in both young and old patients
• Age-related differences in CE were more pronounced at intermediate field intensities (0.5–1.25 T) than at the maximum field strength
• At 1.5 T, CE converged at 8.7% for both age groups for 1000 nm particles

Newtonian rheology consistently over-predicted capture efficiency relative to non-Newtonian rheological models.

• Three non-Newtonian models were compared: Carreau, Power-law, and Casson-Papanastasiou
• Newtonian assumptions did not accurately represent the hemodynamic conditions affecting nanoparticle transport
• This finding highlights the importance of using appropriate blood rheology models in computational MDT studies

All applied magnetic field strengths (0.5–1.5 T) remained within clinically acceptable safety thresholds, and field localization coincided with the target region of interest.

• The study employed a computational framework using patient-specific aortic models reconstructed from clinical imaging
• Magnetic field strengths tested ranged from 0.5 to 1.5 T
• Field localization was confirmed to coincide with the target region of interest in the aortic models

A computational framework was developed to simulate magnetic drug targeting in young and old patient-specific aortic models reconstructed from clinical imaging.

• Blood rheology was modeled using non-Newtonian Carreau, Power-law, and Casson-Papanastasiou models
• Nanoparticle motion was simulated under external magnetic fields ranging from 0.5 to 1.5 T
• Patient-specific aortic geometries were reconstructed from clinical imaging data
• The study compared MDT performance between young and old patient cohorts

Age-related hemodynamic changes, including reduced flow velocity, enlarged aortic lumen, and lower wall shear stress, are the mechanistic drivers of enhanced MDT efficiency in older patients.

• Reduced flow velocity in older patients prolonged nanoparticle residence time in the target region
• Enlarged aortic lumen in older patients contributed to reduced hydrodynamic drag opposing magnetic capture
• Lower wall shear stress in older patients further facilitated nanoparticle capture
• These combined hemodynamic factors collectively enhanced magnetophoretic drug capture in the aged vascular environment