ESOPHAGEAL TRANSIT-TIME EVALUATED BY A BIOMAGNETIC METHOD

The aim of this work was to determine the oesophageal transit time (OT T) of a bolus using the biomagnetic technique and compare the results to those obtained by means of scintigraphy. For the biomagnetic evalua tion, a test meal (yoghurt) uniformly labelled with 5 g of powder ferr ite was swallowed in a single gulp by 19 normal volunteers in the upri ght position. One sensor (first order gradiometer) was placed at the f urcula and a second one at the xiphoid process to detect the passage o f the test meal and the magnetic signal output was recorded in a compu ter. The OTT was determined by plotting the voltage signal against tim e. The scintigraphic technique was used in the same volunteers: the te st meal was labelled with less than 350 MBq of Tc-99m-phytate and swal lowed in the same way. The bolus transit was recorded at 4 frames s(-1 ) (100-120 frames acquisition) and the OTT was determined by drawing t wo regions of interest in the same areas as the sensors. The results w ere determined by plotting counts against time. The averages for OTTs were 3.8 +/- 0.8 s for the scintigraphic technique and 4.6 +/- 0.9 s f or the biomagnetic technique. Although scintigraphic OTT was significa ntly shorter than magnetic OTT, there was a significant correlation be tween them. We conclude that the biomagnetic study may be used to eval uate OTT.