Document Detail

Interindividual variability of arterial impulse response to intravenous injection of nonionic contrast agent (Iohexol) in DCE-CT study.
MedLine Citation:
PMID:  19928109     Owner:  NLM     Status:  MEDLINE    
PURPOSE: It is known that the arterial input function (AIF) in dynamic contrast-enhanced (DCE)-CT differs among patients even for fixed contrast injection protocols. Therefore, a study has been performed to investigate the interindividual variability of the AIF with respect to patient factors (such as weight, height, and age). In addition, it has been demonstrated that the relations from the interindividual variability investigation can be further used for the estimation of AIF for a patient without the requirement of measurement. METHODS: DCE-CT data for a cohort of 34 patients with cervical carcinoma were used for the investigation of interindividual variability of the AIF. To dissociate the effect of different durations of contrast injection, the arterial impulse response (AIR) to intravenous contrast injection was calculated and examined for its correlations with these patient factors. An empirical functional form was proposed to model the AIR with temporal intensity of a first pass of contrast agent followed by recirculation and quasiequilibrium state of contrast concentration. Specific features (onset time, peak time, and amplitudes) of the AIR were tested for correlations with the patient factors. Linear regression was applied to cases that show significant strong correlation between the AIR amplitudes and patient factors. The results were then used to predict the AIR for any given patient based on the patient factors. It was shown that using the predicted AIR, the AIF of the patient can be estimated without the requirement of measurement given the injection protocol is known. The method of AIF estimation was tested in DCE-CT data from another group of 14 patients. The efficacy of individually estimated AIF on pharmacokinetic analysis was assessed against the use of measured AIF and population-averaged AIF as the latter is another possible strategy for AIF generation if AIF measurement is not available. RESULTS: It was found that the amplitudes of AIR postonset time were significantly correlated with patient bodyweight at most time points (r<-0.44, P<0.01) except 8-17 s (P>0.01). When the adiabatic tissue homogeneity (ATH) and the Kety models were applied to the pharmacokinetic analysis, the mean percentage errors in kinetic parameter estimates induced by using the estimated AIF instead of the measured one for both models ranged from -4.98% to 11.19%. CONCLUSIONS: It was found that there are strong linear relationships between AIR and patient weight; thereby the AIR of a patient can be estimated with patient weight. The proposed method of AIF estimation is potentially applicable in cases where AIF measurement is not possible.
S M Kim; M A Haider; M Milosevic; I W T Yeung
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Medical physics     Volume:  36     ISSN:  0094-2405     ISO Abbreviation:  Med Phys     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-11-20     Completed Date:  2010-01-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0425746     Medline TA:  Med Phys     Country:  United States    
Other Details:
Languages:  eng     Pagination:  4791-802     Citation Subset:  IM    
Radiation Medicine Program, Princess Margaret Hospital/University Health Network, Toronto, Ontario M5G 2M9, Canada.
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MeSH Terms
Arteries / metabolism*
Computer Simulation
Contrast Media / pharmacokinetics
Injections, Intravenous
Iohexol / administration & dosage,  diagnostic use*,  pharmacokinetics*
Middle Aged
Models, Biological
Radiographic Image Interpretation, Computer-Assisted / methods*
Reproducibility of Results
Sensitivity and Specificity
Tomography, X-Ray Computed / methods*
Uterine Cervical Neoplasms / blood supply,  metabolism*,  radionuclide imaging*
Grant Support
//Canadian Institutes of Health Research
Reg. No./Substance:
0/Contrast Media; 0/Ions; 66108-95-0/Iohexol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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