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Thoracic [18F]fluorodeoxyglucose uptake measured by positron emission tomography/computed tomography in pulmonary hypertension

View Article: PubMed Central - PubMed

ABSTRACT

Positron emission tomography (PET) visualizes increased cellular [18F]fluorodeoxyglucose ([18F]FDG) uptake. Pulmonary hypertension (PH) is conceived of a proliferative disease of the lung vessels. Increased glucose uptake can be quantified as pulmonary [18F]FDG uptake via PET imaging. Because the angioproliferative mechanisms in PH are still in need of further description, the aim of the present study was to investigate whether [18F]FDG PET/CT imaging can elucidate these pathophysiologic mechanisms in different etiologies of PH.

Patients (n = 109) with end-stage pulmonary disease being evaluated for lung transplant were included in this observational study. Mean standardized uptake value (SUVmean) of predefined regions of interest in lung parenchyma (LP), left (LV), and right ventricle (RV) of the heart, and SUVmax in pulmonary artery (PA) were determined and normalized to liver uptake. These SUV ratios (SUVRs) were compared with results from right heart catheterization (mean pulmonary artery pressure [mPAP], pulmonary vascular resistance [PVR]), and serum N-terminal pro-brain natriuretic peptide. Group comparisons were performed and Pearson correlation coefficients (r) were calculated.

The [18F]FDG uptake ratios in LP, RV, RV/LV, and PA, but not in LV, were found to be significantly higher in both patients with mPAP ≥25 mm Hg (P = 0.013, P = 0.006, P = 0.049, P = 0.002, P = 0.68, respectively) and with PVR ≥480 dyn·s/cm5 (P < 0.001, P = 0.045, P < 0.001, P < 0.001, P = 0.26, respectively). The [18F]FDG uptake in these regions positively correlated also with mPAP, PVR, and N-terminal pro-brain natriuretic peptide. The SUVR of PA positively correlated with the SUVR of LP and RV (r = 0.55, r = 0.42, respectively).

Pulmonary and cardiac [18F]FDG uptake in PET imaging positively correlated with the presence and severity of PH in patients with end-stage pulmonary disease. Increased glucose metabolism in the central PAs seems to play a certain role in terms of severity of PH. These results suggest that [18F]FDG-PET imaging can help understand the pathophysiology of PH as a proliferative pulmonary disease.

No MeSH data available.


Exemplary overview of regions of interest (ROIs) delineated in [18F]FDG-PET/CT fusion images. ROIs of lung parenchyma in 3 different planes: transverse (A–C), coronal (D and F), and sagittal (G and H), of left (I) and right (K) central pulmonary artery, and also of left and right ventricular myocardium (J). Volume of interest (VOI) of liver parenchyma (E) as reference region for semiquantitative analysis. [18F]FDG-PET = [18F]fluorodeoxyglucose positron emission tomography, CT = computed tomography.
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Figure 1: Exemplary overview of regions of interest (ROIs) delineated in [18F]FDG-PET/CT fusion images. ROIs of lung parenchyma in 3 different planes: transverse (A–C), coronal (D and F), and sagittal (G and H), of left (I) and right (K) central pulmonary artery, and also of left and right ventricular myocardium (J). Volume of interest (VOI) of liver parenchyma (E) as reference region for semiquantitative analysis. [18F]FDG-PET = [18F]fluorodeoxyglucose positron emission tomography, CT = computed tomography.

Mentions: The analysis of [18F]FDG uptake was performed using the maximum and mean standardized uptake value (SUVmax and SUVmean, respectively) of the region of interest (ROI), with the help of Hybrid-Viewer Software (Hermes Medical Solutions AB, Stockholm, Sweden) on co-registered PET/CT data: SUVmean for lung parenchyma (LP), left (LV), and right ventricle (RV), and SUVmax for central left and right pulmonary artery (PA). Here, SUVmax was chosen for the PA to capture the vessel uptake of the PA rather than unspecific intraluminal blood pool activity. To access the SUVmean of LP, ROIs were drawn in 3 different planes (3 ROIs in transverse and coronal, and 1 in sagittal plane) per lung (14 ROIs per patient lung) to calculate the mean value of the respective ROIs. The SUVs from the myocardium ROIs (LV, RV) and the right and left PAs were determined likewise in transverse plane (Fig. 1). The SUVs of each ROI were related to the SUVmean of the volume of interest (VOI) of liver parenchyma resulting in SUV ratios (SUVRs). This semiquantitative analysis was performed to obtain a better comparability between the datasets. The distribution of CT-based attenuation correction with and without intravenous (i.v.) contrast enhancement was found to be equal among pulmonary diseases, mPAP, SUVmax, and SUVRmax of the central PA, respectively. In detail, the respective distribution of i.v. contrast versus no contrast in COPD patients was as follows: 64.7% (44/68) of patients versus 35.2% (24/68), the mPAP was 24.5 versus 27.2 mm Hg, SUVmax 2.5 versus 2.3, and the SUVRmax 1.1 versus 1.0. In ILD patients, the distribution of i.v. contrast versus no contrast was as follows: 63.6% (21/33) versus 36.4% (12/33), the mPAP was 37.8 versus 26.0 mm Hg, SUVmax 3.6 versus 2.7, and the SUVRmax 1.3 versus 1.2.


Thoracic [18F]fluorodeoxyglucose uptake measured by positron emission tomography/computed tomography in pulmonary hypertension
Exemplary overview of regions of interest (ROIs) delineated in [18F]FDG-PET/CT fusion images. ROIs of lung parenchyma in 3 different planes: transverse (A–C), coronal (D and F), and sagittal (G and H), of left (I) and right (K) central pulmonary artery, and also of left and right ventricular myocardium (J). Volume of interest (VOI) of liver parenchyma (E) as reference region for semiquantitative analysis. [18F]FDG-PET = [18F]fluorodeoxyglucose positron emission tomography, CT = computed tomography.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4998336&req=5

Figure 1: Exemplary overview of regions of interest (ROIs) delineated in [18F]FDG-PET/CT fusion images. ROIs of lung parenchyma in 3 different planes: transverse (A–C), coronal (D and F), and sagittal (G and H), of left (I) and right (K) central pulmonary artery, and also of left and right ventricular myocardium (J). Volume of interest (VOI) of liver parenchyma (E) as reference region for semiquantitative analysis. [18F]FDG-PET = [18F]fluorodeoxyglucose positron emission tomography, CT = computed tomography.
Mentions: The analysis of [18F]FDG uptake was performed using the maximum and mean standardized uptake value (SUVmax and SUVmean, respectively) of the region of interest (ROI), with the help of Hybrid-Viewer Software (Hermes Medical Solutions AB, Stockholm, Sweden) on co-registered PET/CT data: SUVmean for lung parenchyma (LP), left (LV), and right ventricle (RV), and SUVmax for central left and right pulmonary artery (PA). Here, SUVmax was chosen for the PA to capture the vessel uptake of the PA rather than unspecific intraluminal blood pool activity. To access the SUVmean of LP, ROIs were drawn in 3 different planes (3 ROIs in transverse and coronal, and 1 in sagittal plane) per lung (14 ROIs per patient lung) to calculate the mean value of the respective ROIs. The SUVs from the myocardium ROIs (LV, RV) and the right and left PAs were determined likewise in transverse plane (Fig. 1). The SUVs of each ROI were related to the SUVmean of the volume of interest (VOI) of liver parenchyma resulting in SUV ratios (SUVRs). This semiquantitative analysis was performed to obtain a better comparability between the datasets. The distribution of CT-based attenuation correction with and without intravenous (i.v.) contrast enhancement was found to be equal among pulmonary diseases, mPAP, SUVmax, and SUVRmax of the central PA, respectively. In detail, the respective distribution of i.v. contrast versus no contrast in COPD patients was as follows: 64.7% (44/68) of patients versus 35.2% (24/68), the mPAP was 24.5 versus 27.2 mm Hg, SUVmax 2.5 versus 2.3, and the SUVRmax 1.1 versus 1.0. In ILD patients, the distribution of i.v. contrast versus no contrast was as follows: 63.6% (21/33) versus 36.4% (12/33), the mPAP was 37.8 versus 26.0 mm Hg, SUVmax 3.6 versus 2.7, and the SUVRmax 1.3 versus 1.2.

View Article: PubMed Central - PubMed

ABSTRACT

Positron emission tomography (PET) visualizes increased cellular [18F]fluorodeoxyglucose ([18F]FDG) uptake. Pulmonary hypertension (PH) is conceived of a proliferative disease of the lung vessels. Increased glucose uptake can be quantified as pulmonary [18F]FDG uptake via PET imaging. Because the angioproliferative mechanisms in PH are still in need of further description, the aim of the present study was to investigate whether [18F]FDG PET/CT imaging can elucidate these pathophysiologic mechanisms in different etiologies of PH.

Patients (n = 109) with end-stage pulmonary disease being evaluated for lung transplant were included in this observational study. Mean standardized uptake value (SUVmean) of predefined regions of interest in lung parenchyma (LP), left (LV), and right ventricle (RV) of the heart, and SUVmax in pulmonary artery (PA) were determined and normalized to liver uptake. These SUV ratios (SUVRs) were compared with results from right heart catheterization (mean pulmonary artery pressure [mPAP], pulmonary vascular resistance [PVR]), and serum N-terminal pro-brain natriuretic peptide. Group comparisons were performed and Pearson correlation coefficients (r) were calculated.

The [18F]FDG uptake ratios in LP, RV, RV/LV, and PA, but not in LV, were found to be significantly higher in both patients with mPAP ≥25 mm Hg (P = 0.013, P = 0.006, P = 0.049, P = 0.002, P = 0.68, respectively) and with PVR ≥480 dyn·s/cm5 (P < 0.001, P = 0.045, P < 0.001, P < 0.001, P = 0.26, respectively). The [18F]FDG uptake in these regions positively correlated also with mPAP, PVR, and N-terminal pro-brain natriuretic peptide. The SUVR of PA positively correlated with the SUVR of LP and RV (r = 0.55, r = 0.42, respectively).

Pulmonary and cardiac [18F]FDG uptake in PET imaging positively correlated with the presence and severity of PH in patients with end-stage pulmonary disease. Increased glucose metabolism in the central PAs seems to play a certain role in terms of severity of PH. These results suggest that [18F]FDG-PET imaging can help understand the pathophysiology of PH as a proliferative pulmonary disease.

No MeSH data available.