Scintigraphic detection of gastro‐pulmonary aspiration in patients with respiratory disorders

Abstract

The scintigraphic detection of small nocturnal aspirations of radio-labelled gastric contents is difficult in the presence of high remaining activity in the abdomen, causing a non-uniform background activity. This problem was examined in phantom experiments and a technique for interpolative background correction was further developed. The accuracy of this technique was found to be influenced by the distance between the lung and the abdominal source of activity, and the minimum detectable 'aspirated' activity was determined as 0.1 MBq at a distance of 15 cm and 1 MBq at 5 cm. The interpolative technique for background correction was evaluated on healthy volunteers and laryngectomized patients, examined 10 h after intragastric instillation of 200 MBq of 99Tcm-pertechnetate. After background subtraction, their calculated pulmonary mean net count value was comparable to that registered before the radioactive tracer was administered. No localized accumulation of activity was found in any of these controls. The technique was then applied clinically to 55 patients with chronic respiratory disorders and symptoms of gastroesophageal reflux. Aspiration was detected in 11 patients (20%). Five aspirators had asthma, two a chronic cough of unknown origin, two recurrent pulmonary infections, and one chronic bronchitis and chronic laryngitis respectively. Aspiration was detected among patients with and without demonstrated pathological gastroesophageal reflux.

Hypopharyngeal and distal esophageal pH monitoring in children with gastroesophageal reflux and respiratory symptoms

“…The specificity of the latter is reported to be as low as 57% [4], whereas contrast studies and scintigraphy have low sensitivity [5]. Prolonged intraesophageal pH monitoring is widely regarded as the gold standard for diagnosing GER.…”

Acid suppression does not change respiratory symptoms in children with asthma and gastro-oesophageal reflux disease

“…[3][4][5][6] A causative relation is still unclear, even though acid perfusion of the lower oesophagus may induce bronchoconstriction in animal models 7 and in humans, 8 9 probably mediated through a vagal reflex. 9 Microaspiration is an alternative pathophysiological mechanism, as shown by scintigraphic studies 10 and analyses of bronchoalveolar lavage fluid. 11 12 A limited number of studies reviewed in a recent Cochrane report 13 have evaluated the effect of GORD treatment, with conflicting results with respect to asthma symptoms and lung function.…”

Association of gastro esophageal reflex with chronic asthma and its significance: a prospective study

“…Ruth M et al in their study have shown that pulmonary scintigraphy is low sensitivity and has a diagnostic yield below 20%, but a positive test result is of great diagnostic value. 10 The male to female ration in our study was 1.6:1 and three was no significant correlation between sex and efflux x 2 =0.…”