427. THE ROLE OF CROSS-SECTIONAL IMAGING IN PATIENTS WITH PULMONARY MICRO ASPIRATION

Abstract Background There is increasing evidence of a strong relationship between pulmonary microaspiration of refluxate and pulmonary diseases such as bronchiectasis and lung fibrosis. This group has demonstrated the presence of co-location of pulmonary aspiration on modified reflux scintigraphy with lobar parenchymal lung changes on high resolution computed tomographic imaging of the lung (HRCT-L) in patients with typical and atypical reflux symptoms. There is, however, a cohort of patients who demonstrate evidence of reflux aspiration without evidence of parenchymal changes on HRCT-L. This study aims to demonstrate a group of patients with confirmed reflux micro-aspiration without corresponding changes in lung parenchyma on HRCT. Methods Data were obtained from a prospectively populated database of patients with treatment resistant typical and atypical GORD and suspected reflux pulmonary microaspiration. Modified novel digital technique of reflux pulmonary microaspiration scintigraphy using a previously validated technique was performed to evaluate the possibility of significant GORD or extra-oesophageal symptoms, including typical symptoms such as heartburn and reflux and atypical symptoms such as throat symptoms, cough, globus, mucous, throat clearing, dysphonia and recurrent respiratory infections. Patients who underwent microaspiration studies and had normal HRCT-L for chest symptoms were included. The group was compared to patients with lung changes on HRCT-L corresponding with micro-aspiration studies. Results Inclusion criteria were met by 14 patients (86% female, 14% male). The mean age was 54 years (range: 36 – 81 years). All patients demonstrated reflux microaspiration on scintigraphy in the supine delayed phase and all had intermittent or continuous full column gastro-oesophageal reflux. Lung parenchymal changes on HRCT-L corresponding to site of reflux micro-aspiration on scitigraphy were demonstrated in 66 out of 80 patients listed in the database. Amongst patients with normal HRCT-L typical reflux symptoms were reported in 1 patient, atypical symptoms in 6 patients, both in 5 patients and 2 did not report symptoms. Most common presenting symptom was cough. There was no difference in symptomatology of patients with or without HRCT-L pulmonary parenchymal changes. Patients with pulmonary changes on HRCT were on average 13 years older than patients without CT changes (mean age 67, range 31-91). Conclusion HRCT-L is an important additional investigation in patient with reflux micro-aspiration detected on scintigraphy to identify patients with reflux related lung parenchymal changes. Younger age of patients with normal HRCT-L suggests that parenchymal changes may be developing as a result of prolonged exposure to reflux micro-aspiration over time.