SummaryThe conventional method of lung scanning detects defects of pulmonary artery perfusion. False positive results occur because regions of hypoventilation, such as are present in obstructive airways disease, also cause defects of perfusion. The converse is not true, however, as defects of perfusion continue to be ventilated. Thus in pulmonary embolism ventilation-perfusion discrepancy (normal ventilation and impaired perfusion) occursWe have assessed the clinical value of this discrepancy. Out of 18 patients with ventilation-perfusion discrepancy 14 had a final diagnosis of pulmonary emboli, whereas in none of the 34 patients without the discrepancy was this final diagnosis made. We conclude that combined ventilationperfusion lung scanning distinguishes pulmonary emboli from other lung conditions such as asthma and bronchitis which cause impaired pulmonary perfusion. The false positive rate was only 4% overall and 7-7% in patients with perfusion defects. IntroductionLung perfusion scanning is of value in the diagnosis of pulmonary embolism and is a simple and safe screening proced-

A malignant nerve sheath tumour arising within a thoracic ganglioneuroma is described. This is only the seventh such case described in the literature and the first at this site. The previously documented cases are reviewed.

Reports were made on combined ventilation-perfusion lung scans by three observers on three occasions and by another observer once. Reproducibility for each observer varied between 80 and 88%. There was complete agreement about the areas of scans reported as abnormal. Agreement between observes on whether or not the abnormality represented a pulmonary embolus averaged 77%. There was 86% agreement with the final clinical diagnosis. Our results show that reporting of ventilation perfusion lung scans by eye is reproducible. They support the claims that, under routine clinical conditions, the technique is 91% to 95% accurate for pulmonary emboli.

One hundred and sixteen patients with suspected lung malignancy who were referred for bronchoscopy were examined using both the flexible fibreoptic bronchoscope and the rigid bronchoscope. Both instruments were used sequentially under the same general anaesthetic. Brush biopsies were obtained through the fibreoptic bronchoscope and conventional biopsies, for histological examination, through the rigid bronchoscope. Both specimens were taken from the same area. Eighty-two per cent of those in whom there was a final clinical diagnosis of malignancy were found to have abnormal cytology via the fibreoptic bronchoscope, while abnormal histology was found in 50% by means of the rigid bronchoscope. For those in whom malignancy was confirmed, 16-9 % showed disagreement between the two methods in cell typing. Brush biopsy through the flexible fibreoptic bronchoscope under general anaesthesia is confirmed as a sensitive method for diagnosing lung malignancy.

No abstract