99mTc-IgG-lung scintigraphy in the assessment of pulmonary involvement in interstitial lung disease (ILD) and its comparison with pulmonary function tests (PFTs) and high-resolution computed tomography (HRCT): A preliminary study

Objectives The discrimination of inactive inflammatory processes from active form of the disease is of great importance in the management of interstitial lung disease (ILD). The aim of this study was to determine the efficacy of 99m Tc-IgG scan for the detection of severity of the disease compared to HRCT and PFT.

Methods Eight known case of ILD were included in this study. A population of 6 patients without lung disease was considered as control group. The patients underwent pulmonary function test (PFT) and high-resolution computed tomography scan, followed by 99mTc-IgG scanning. They were followed up for one year.

Results All 8 ILD patients demonstrated a strong increase in 99m Tc-IgG uptake in the lungs, compared to control patients. 99mTc-IgG scan scores were higher in patient’s group (0.64(0.61-0.69)) than in control group (0.35(0.28-0.40)( p<0.05). In patients, a statistically significant positive correlation was detected between 99mTc-IgG scan and HRCT scores (spearman’s correlation coefficient= 0.92, p< 0.008). There were no significant correlation between 99mTc-IgG scan score with HRCT patterns including ground glass opacity, reticular fibrosis and honeycombing (P value >0.05).

Conclusions The present preliminary results confirmed that 99mTc-IgG scan can be applied to detect the severity of pulmonary involvement in early views which was well correlated with HRCT findings. This data also showed that the use of 99m Tc-IgG scan in lung studies might be used as a complement to HRCT in the functional evaluation of the clinical status in ILD; however, further studies are recommended.