P107 Pulmonary imaging techniques to identify suitable patients and act as outcome measures in the UK CF Gene Therapy Consortium clinical programme

We are conducting a large, longitudinal study to assess outcome measures and identify optimal patients for a multidose trial of CF gene therapy. Two imaging modalities are being employed: radioisotope deposition scans and high resolution CT. Subjects have undergone these scans on a single occasion, whilst clinically stable. The purpose was: Deposition scan —to determine which patients would be most optimal for topical drug delivery and CT —to assess the suitability of various parameters as efficacy measures. Following inhalation of 99m Tc-labelled human serum albumin, planar gamma camera images and SPECT were used to assess 3-D deposition. Images were scored both digitally and visually (I- no defects; II- patchy deposition; III- patchy deposition with large defects; IV- grossly abnormal). HRCT scans were scored by two radiologists on a lobar basis for the following: bronchiectasis (extent/severity), airway wall thickening, mucus plugging and gas trapping. 147 deposition scan were available; digital indices (DI) ranged from 34 (best) to 150 (severely abnormal). Visual scores correlated well with DI (R2 0.63; p 1 % (p 1 of 43.9(4.3)%, significantly lower than groups I-III (p