Idiopathic pulmonary fibrosis and diffuse parenchymal lung disease: implications from initial experience with 18F-FDG PET/CT.
The purpose of this study was to evaluate integrated (18)F-FDG PET/CT in patients with idiopathic pulmonary fibrosis (IPF) and diffuse parenchymal lung disease (DPLD).


METHODS
Thirty-six consecutive patients (31 men and 5 women; mean age +/- SD, 68.7 +/- 9.4 y) with IPF (n = 18) or other forms of DPLD (n = 18) were recruited for PET/CT and high-resolution CT (HRCT), acquired on the same instrument. The maximal pulmonary (18)F-FDG metabolism was measured as a standardized uptake value (SUV(max)). At this site, the predominant lung parenchyma HRCT pattern was defined for each patient: ground-glass or reticulation/honeycombing. Patients underwent a global health assessment and pulmonary function tests.


RESULTS
Raised pulmonary (18)F-FDG metabolism in 36 of 36 patients was observed. The parenchymal pattern on HRCT at the site of maximal (18)F-FDG metabolism was predominantly ground-glass (7/36), reticulation/honeycombing (26/36), and mixed (3/36). The mean SUV(max) in patients with ground-glass and mixed patterns was 2.0 +/- 0.4, and in reticulation/honeycombing it was 3.0 +/- 1.0 (Mann-Whitney U test, P = 0.007). The mean SUV(max) in patients with IPF was 2.9 +/- 1.1, and in other DPLD it was 2.7 +/- 0.9 (Mann-Whitney U test, P = 0.862). The mean mediastinal lymph node SUV(max) (2.7 +/- 1.3) correlated with pulmonary SUV(max) (r = 0.63, P < 0.001). Pulmonary (18)F-FDG uptake correlated with the global health score (r = 0.50, P = 0.004), forced vital capacity (r = 0.41, P = 0.014), and transfer factor (r = 0.37, P = 0.042).


CONCLUSIONS
Increased pulmonary (18)F-FDG metabolism in all patients with IPF and other forms of DPLD was observed. Pulmonary (18)F-FDG uptake predicts measurements of health and lung physiology in these patients. (18)F-FDG metabolism was higher when the site of maximal uptake corresponded to areas of reticulation/honeycomb on HRCT than to those with ground-glass patterns.
Groves
Ashley M
AM
Institute of Nuclear Medicine, University College London, London, United Kingdom.
Win
Thida
T
Screaton
Nicholas J
NJ
Berovic
Marko
M
Endozo
Raymondo
R
Booth
Helen
H
Kayani
Irfan
I
Menezes
Leon J
LJ
Dickson
John C
JC
Ell
Peter J
PJ
D000368:Aged; D003937:Diagnosis, Differential; D019788:Fluorodeoxyglucose F18; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000175:diagnosis*; D008297:Male; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods*; D011658:Pulmonary Fibrosis / Q000175:diagnosis*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18