ABSTRACTS oing in pulmonary embolism. The frequency, indications and specific techniques involved were assessed. There was a 94% response rate including 48 (out of 50) teaching or cardiothoracic units. Lung scanning was provided by only 199 (59%) hospitals and angiography by 120 (36%), with 99 providing both. Average numbers of V/Q scans performed were 19.8 per month, compared with an average of 12.0 angiograms (in total) performed for suspected embolism over the preceding 3 years. In 18 %, one (or less) angiograms were performed in the same period. Teaching cardiac hospitals performed more V/Q scans (p<0.001) and more angiograms (P<0.001) than other hospitals. Indications for angiography were investigation of suspected embolism with and without prior lung scan (53% and 31% respectively) and investigation o f other conditions (16%). Of specific indications, investigation of patients with indeterminate lung scans (63%), and consideration of thrombolysis (45%) and embolectomy (30%) were the most frequent given. Pulmonary angiography is used in the U K in no more than a small percentage of patients with suspected thromboembolism, in contrast with the widespread and frequent use o f lung scanning. THE DETECTION OF INTERSTITIAL LUNG DISEASE WITH ADVANCED M U L T I P L E BEAM EQUALIZATION RADIOGRAPHY (AMBER) COMPARED TO CONVENTIONAL CHEST RADIOGRAPHY: AN ROC STUDY D. M. HANSELL, R. D U BOIS and R. C O L E M A N
The Royal Brompton and National Heart Hospitals, London The Advanced Multiple Beam Equalization Radiography (AMBER) chest unit optimizes the exposure throughout a chest radiograph by dynamic feedback control of a segmented and collimated X-ray beam which sweeps through the patient. The overall detection of focal pulmonary lesions with this device is significantly higher than with standard chest radiography because of the improved demonstration of the costophrenic and retro-cardiac regions of the chest. It has not been established whether scanning equalization radiographic devices, such as the A M B E R unit, significantly affect the conspicuity of broad areas of different radiographic density. This has particular relevance to the detection of those interstitial lung diseases which present radiographically with subtle diffuse opacification of the lungs. The purpose of this study was to determine whether there is any significant difference in observer performance in the detection of subtle diffuse lung between AMBER chest radiographs and conventional chest radiographs. Twenty-one patients with interstitial lung disease (cryptogenic fibrosing alveolitis or sarcoidosis) and six patients with no pulmonary disease had high kVp P A and lateral chest radiographs on both an A M B E R unit and a conventional chest stand. The pooled results of five observers using Receiver Operating Characteristics analysis indicate that there is no significant difference in observer performance between A M B E R (Area under the ROC curve: Az = 0.934) and conventional radiography (Az= 0.868) in the task of detecting diffuse lung disease. THE EFFECT ON VARIOUS PHYSIOLOGICAL PARAMETERS OF EMBOLIZATION OF P U L M O N A R Y ARTERIOVENOUS M A L F O R M A T I O N S J. E. JACKSON, M. WHYTE, J. M. B. H U G H E S and D. J. ALLISON
Royal Postgraduate Medical School, Hammersmith Hospital, London The effects of percutaneous transcatheter embolization on pulmonary function were assessed in 15 patients with pulmonary arteriovenous malformations (PAVMs). Eleven patients had associated hereditary haemorrhagic telangiectasia. Vital capacity (VC), FEVb DLoo, SaO2, exercise tolerance and right to left shunt (100% oxygen method) were measured before and 2-6 months after treatment. Before embolization, lung function tests showed normal VC and FEVI/VC ratios, reduced l)L~o (mean 71% predicted, range 36-123%), a resting supine SaO2 of 86% (range67-95%) a n d a m e a n shunt fractionof33% (range 15 47%). Despite further marked falls in SaO2 on exertion, exercise capacity was well preserved. Following embolization with steel coils of all PAVMs with a feeding vessel o f >3 mm (1 4 sessions per patient) mean shunt fraction improved from 33% to 19% and resting Sa02 from 86% to 92% with no change in VC. Exercise tolerance improved in the majority (unchanged in 6), and SaO2 during maximal exercise improved in all except one patient. There were no long term complications following embolization. Embolization of macroscopic PAVMs is undertaken primarily to reduce the risk of paradoxical embolization. These findings indicate that erabolization is safe and results in substantial improvements in resting and exercise SaO2 without evidence of loss of normal lung. The residual right-to-left shunt following embolization may reflect the presence of numerous microscopic PAVMs.
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THE VALUE OF A NEGATIVE INITIAL FINE-NEEDLE BIOPSY IN OPERABLE LUNG M. J. CHARIG, J. E. STUTLEY and D. M. H A N S E L L
Brompton Hospital, London The value of fine-needle biopsy (FNB) of pulmonary masses in patients not suitable for surgery is well established. One-hundred and ninety-six patients over the age of 40 referred with a solitary pulmonary mass were studied retrospectively to assess the management consequences o f the initial FNB when no malignant cells were obtained and the mass was considered to be operable. Malignant cells were discovered in 148 patients and diagnoses of infection were made in a further 10. Of the remaining 38 patients, 13 were inoperable on the basis of metastatic disease or general debility. Twenty-five patients were considered to be operable and 20 of these patients underwent surgery, the other five being followed up with no subsequent evidence of malignancy demonstrated. It is concluded that if a solitary pulmonary nodule gives rise to a high clinical suspicion of malignancy and the patient is a candidate for surgery then FNB has little value in the management of the patient. REAL TIME ULTRASOUND SIGNS IN PLEURAL FLUID COLLECTIONS D. J. LOMAS and C. D. R. F L O W E R
Addenbrooke's Hospital, Cambridge Ultrasound of the pleural space is a sensitive method of detecting pleural fluid in patients with equivocal chest radiographs, or in whom prior blind aspiration has failed. This study assesses the presence of dynamic signs in proven fluid collections. Fifty-one patients with 53 suspected pleurat collections were referred for chest ultrasound. The appearances were prospectively recorded. In 17 cases aspiration was not attempted owing to underlying normal or consolidated lung or because a collection of less than 1 cm in depth was present. The remaining 36 cases underwent successful aspiration of fluid at a marked site within 24 hours. Of these 81% were anechoic and 19% echogenic in appearance. Flapping movements of the lung, fibrinous debri, or septae were present in 86% (31/36) and swirling motion of the echoes were detected in 43 % (3/7) of the echogenic collections. We conclude that dynamic signs, in particular flapping movements, are a common occurrence in pleurat fluid collections and may be a useful guide to the presence of fluid. ULTRASOUND APPEARANCES OF ASBESTOS RELATED PLEURAL P L A Q U E R. M O R G A N , F. PICKWORTH, P. DUBBINS and C. M c G A V I N
Derriford Hospital, Plymouth The frequency of appearance o f asbestos related lung disease and pleural plaque on routine chest X-ray is high in the Plymouth hospitals as a result of employment in the Royal Naval Dockyards. Juxta-diaphragmatic asbestos related pleural plaque is also commonly seen during routine upper abdominal ultrasound scans in the Plymouth hospitals. Based on the X-ray features of 25 patients with known asbestos relhted lung disease the ultrasound features of pleural plaque are described. Ultrasound was more sensitive in the detection of juxta-diaphragmatic plaque rather than plaque related to the lateral chest walls. Pleural plaque appeared as a regular area of echo-poor tissue which was well defined adjacent to the diaphragm or lateral chest wall. Pleural plaque thickness varied from 2 14 mm. Calcification was demonstrated and in this situation measurement of the plaque thickness was compromised. In a number of cases ultrasound demonstrated that the thickness of diaphragmatic plaque was greater than suggested on a PA chest X-ray and a rote for ultrasound in the evaluation of asbestos related pleural plaque is proposed with possible implications in disputed claims for compensation. LASER ASSISTED A N G I O P L A S T Y - A REVIEW OF THE PUBLISHED EVIDENCE N. A K H T A R and G. G. H A R T N E L L
Bristol Royal Infirmary, Bristol Lasers have been used in angioplasty for several years, but in spite of favourable reports the Society of Cardiovascular and Interventional Radiology states that lasers are not routinely indicated in angioplasty and should be restricted to research programmes.