Ali Salavati MD, MPH, Presenter: Nothing to Disclose

Sina Houshmand MD, Abstract Co-Author: Nothing to Disclose

Boon-Keng Kevin Teo PhD, Abstract Co-Author: Nothing to Disclose

Benjapa Khiewvan, Abstract Co-Author: Nothing to Disclose

Habib Zaidi MSc, PhD, Abstract Co-Author: Nothing to Disclose

Drew Avedis Torigian MD, MA, Abstract Co-Author: Nothing to Disclose

Abass Alavi MD, Abstract Co-Author: Nothing to Disclose

To compare the impact of simultaneous use of respiratory gating with partial volume effect correction on the accurate quantification of FDG-PET/CT parameters in patients with lung cancer. 

The study included 106 lesions of 55 lung cancer patients who underwent respiratory-gated FDG-PET/CT for radiation therapy treatment planning. Volumetric PET/CT parameters were determined by using both 4D PET/CT and non-gated PET/CT images. We used a semi-automatic program employing an adaptive contrast-oriented thresholding algorithm for segmentation as well as a lesion based partial volume effect correction algorithm. We compared respiratory-gated parameters with non-gated parameters by using pairwise comparison and interclass correlation coefficient assessment. In a multivariable regression analysis we also examined factors, which can affect quantification accuracy, including the size of lesion and the location of tumor.

We observed a minor difference in FDG uptake and volumetric parameters of lesions by comparing the highest respiratory-gated values versus non-gated PET/CT values. After correction for partial volume effect, the mean standardized uptake value (SUVmean) and total lesion glycolysis (TLG) increased substantially (p-value < 0.001). However, we did not observe a significant difference between partial volume corrected parameters of respiratory gated and non-gated PET/CT scans. Regression analysis showed that tumor volume is the single most significant predictor of quantification inaccuracy that was mainly caused by partial volume effect.

Based on this study, volumetric and partial volume corrected parameters of non-gated PET/CT images are comparable to respiratory-gated PET/CT parameters. Partial volume correction increased both the respiratory-gated and non-gated values significantly and appears to be the dominant source of quantification inaccuracy particularly in small lesions.

Accurate quantification of lung malignancies is an important part of treatment planning and response monitoring in clinics. In this study, we compared factors causing inaccurate quantification in clinical practice.

Salavati, A, Houshmand, S, Teo, B, Khiewvan, B, Zaidi, H, Torigian, D, Alavi, A, Application of Partial Volume Effect Correction and 4D PET/CT in the Accurate Quantification of Lung Cancer Lesions.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14016606.html