Influence of partial volume on venous output and arterial input function.

Area of Science:

• Neuroimaging
• Radiology
• Cerebrovascular Imaging

Background:

• CT perfusion (CTP) is crucial for assessing cerebral hemodynamics, requiring arterial input function (AIF) and venous output function (VOF) measurements for quantitative perfusion parameters.
• Partial volume effects (PVEs) can compromise AIF and VOF accuracy, necessitating evaluation of their impact on perfusion metrics.
• Current methods often assume VOF measurements are unaffected by PVEs, a premise this study investigates.

Purpose of the Study:

• To evaluate the impact of PVE on AIF and VOF measurements in CTP.
• To determine how PVE influences absolute perfusion parameters like CBV, CBF, and MTT.
• To provide recommendations for optimizing CTP acquisition to minimize PVE.

Main Methods:

• Quantified the area under the curve (AUC) of AIF and VOF in 10 patients across 3-, 6-, and 12-mm-thick CTP sections.
• Compared differences in VOF AUC, AIF AUC, and AIF width across varying section thicknesses.
• Analyzed the consequential influence on absolute CBV, CBF, and MTT values.

Main Results:

• Thinner CTP sections significantly increased both VOF and AIF AUC values.
• A slight decrease in AIF width was observed with thinner sections.
• Differences in AUC were more pronounced for the AIF compared to the VOF across section thicknesses.

Conclusions:

• PVEs significantly affect both AIF and VOF measurements in CTP.
• The use of thicker sections leads to overestimation of cerebral blood volume (CBV) and cerebral blood flow (CBF).
• Performing VOF measurements at lower section thicknesses is recommended to mitigate PVE and ensure accurate perfusion quantification.