Can dynamic imaging, using 18F-FDG PET/CT and CT perfusion differentiate between benign and malignant pulmonary nodules?

Aleksander Marin,Saeed Mirsadraee,Adriana A.S Tavares,Vladka Salapura,Kristopher M Skwarski,John T Murchison,William A Wallace,Alison Fletcher,Edwin J.R Van Beek

doi:10.2478/raon-2021-0024

Aleksander Marin, Saeed Mirsadraee + Show 7 more

Open Access

https://doi.org/10.2478/raon-2021-0024

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Abstract

BackgroundThe aim of the study was to derive and compare metabolic parameters relating to benign and malignant pulmonary nodules using dynamic 2-deoxy-2-[fluorine-18]fluoro-D-glucose (18F-FDG) PET/CT, and nodule perfusion parameters derived through perfusion computed tomography (CT).Patients and methodsTwenty patients with 21 pulmonary nodules incidentally detected on CT underwent a dynamic 18F-FDG PET/CT and a perfusion CT. The maximum standardized uptake value (SUVmax) was measured on conventional 18F-FDG PET/CT images. The influx constant (Ki) was calculated from the dynamic 18F-FDG PET/CT data using Patlak model. Arterial flow (AF) using the maximum slope model and blood volume (BV) using the Patlak plot method for each nodule were calculated from the perfusion CT data. All nodules were characterized as malignant or benign based on histopathology or 2 year follow up CT. All parameters were statistically compared between the two groups using the nonparametric Mann-Whitney test.ResultsTwelve malignant and 9 benign lung nodules were analysed (median size 20.1 mm, 9–29 mm) in 21 patients (male/female = 11/9; mean age ± SD: 65.3 ± 7.4; age range: 50–76 years). The average SUVmax values ± SD of the benign and malignant nodules were 2.2 ± 1.7 vs. 7.0 ± 4.5, respectively (p = 0.0148). Average Ki values in benign and malignant nodules were 0.0057 ± 0.0071 and 0.0230 ± 0.0155 min-1, respectively (p = 0.0311). Average BV for the benign and malignant nodules were 11.6857 ± 6.7347 and 28.3400 ± 15.9672 ml/100 ml, respectively (p = 0.0250). Average AF for the benign and malignant nodules were 74.4571 ± 89.0321 and 89.200 ± 49.8883 ml/100g/min, respectively (p = 0.1613).ConclusionsDynamic 18F-FDG PET/CT and perfusion CT derived blood volume had similar capability to differentiate benign from malignant lung nodules.

Highlights

The demographic data, average nodule size, SUVmax, metabolic parameter relating to the pulmonary nodules through dynamic 18F-FDG positron emission tomography (PET)/ computed tomography (CT), and perfusion parameters through perfusion CT for the benign and malignant nodules are summarised in Table 1 and Figure 3
Final diagnosis was determined after surgical resection in 10 patients, core CT guided biopsy or bronchoscopy in 6 patients, and over 2 years stability on follow up CT imaging in 5 patients
Our results demonstrate that the metabolic parameter Ki of dynamic 18F-FDG PET/CT and the blood volume (BV) parameter of perfusion CT are significantly lower in benign nodules

Summary

Introduction

CT characterisation using only morphological features is imprecise[6,7], leading to an increased interest in computer-based radiomics assessment.[8,9,10,11,12,13,14,15] Serial CT imaging to monitor nodule size can be problematic as nodule growth varies with different cancers and causes patient anxiety.16–18 18F-FDG PET has high sensitivity but lower specificity of 82% for detecting malignant pulmonary nodules, in those smaller than 10 mm.[19] Imaging guided sampling of small nodules is difficult, is associated with complications, and its diagnostic yield decreases further as nodule size decreases.[3,20,21]. The aim of the study was to derive and compare metabolic parameters relating to benign and malignant pulmonary nodules using dynamic 2-deoxy-2-[fluorine-18]fluoro-D-glucose (18F-FDG) PET/CT, and nodule perfusion parameters derived through perfusion computed tomography (CT)

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