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Journal of Computer Assisted Tomography:
doi: 10.1097/RCT.0000000000000053
Abdominal Imaging

Effect of Pre–Enhancement Set Point on Computed Tomographic Perfusion Values in Normal Liver and Metastases to the Liver From Neuroendocrine Tumors

Ng, Chaan S. MD*; Chandler, Adam G. PhD†‡; Yao, James C. MD§; Herron, Delise H. BS*; Anderson, Ella F. RT*; Charnsangavej, Chusilp MD*; Hobbs, Brian P. PhD, MS

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Abstract

Objective

The objective of this study was to assess the effects of pre–enhancement set point (T1) positioning on computed tomographic perfusion (CTp) parameter values.

Methods

The CTp data from 16 patients with neuroendocrine liver metastases were analyzed with distributed parameter modeling to yield tissue blood flow (BF), blood volume, mean transit time, permeability, and hepatic arterial fraction for tumor and normal liver, with displacements in T1 of ±0.5, ±1.0, ±2.0 seconds, relative to the reference standard. A linear mixed-effects model was used to assess the displacement effects.

Results

Effects on the CTp parameter values were variable: BF was not significantly affected, but T1 positions of ≥+1.0 second and −2.0 seconds or longer significantly affected the other CTp parameters (P ≤ 0.004). Mean differences in the CTp parameter values versus the reference standard for BF, blood volume, mean transit time, permeability, and hepatic arterial fraction ranged from −5.0% to 5.2%, −12.7% to 8.9%, −12.5% to 8.1%, −5.3% to 5.7%, and −12.9% to 26.0%, respectively.

Conclusions

CTp parameter values can be significantly affected by T1 positioning.

Copyright © 2014 by Lippincott Williams & Wilkins

  

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