ABSTRACTS 553

treated as in-patients at St Thomas ' s . The role of the radiologist both in t reatment and assessment , before and after therapy, will be discussed, particularly with regard to the routine use of plain abdominal radiogra- phy, intravenous urography and renal ultrasonography. Auxiliary radiological procedures were required in 13% of treatments. These included percutaneous nephros tomy both for drainage and for place- ment of tubes for subsequent nephrol i thotomy. The success of treat- ment was evaluated inter alia by an intravenous urogram at 3 months .

These results, together with the particular problems associated with intra-ureteric stones will be discussed. The practical difficulties associ- ated with there being only one National Lithotripter Centre in a country with a population of 57 million will be stressed.

ADOLESCENT DISC DISEASE: A CLINICO-RADIOLOGICAL STUDY B. S. W O R T H I N G T O N , M. J. GIBSON, J. B U C K L E Y and R. C. M U L H O L L A N D Queen's Medical Centre, Nottingham

Lumbar disc injury in the adolescent is relatively uncommon but forms a distinctive subgroup of disc disease. A study was carricd out compar- ing the findings of MRI of 16 such patients with an age matched asymptomatic control group.

The lumbo-sacral spine of the patients and control group was scan- ned in the sagittal and transverse axial plan on a 0.15 T resistive MRI unit. A variety of imaging sequences was used, including in all cases T2 weighted sequence (TR 200 msecs, TE 40 msecs) so as to highlight the signal from the nucleus pulposus.

In all paticnts the examinat ion revealed a posterior protrusion of a lumbar disc at one or more levels with a fusiform deformity of the nucleus extending into the a t tenuated rim of annulus. Other abnor- malities included irregularity of the nuclei outlines and reduction in signal intensity consistent with p remature degeneration. Ten patients had abnormalit ies at more than one level and in a half of these three levels were involved. In the control group of 20 asymptomatic sub- jects, four had a single level disc abnormali ty at L5/SI .

The occurrence in this age group of disc disease at multiple levels in over half of the patients raises the possibility of a diathisis towards the development of disc abnormality. The findings of a single level abnor- mality in 20% of the control group emphasises that an abnormal disc can be asymptomatic and that degenerat ion may have its inception at a younger age than hitherto supposed.

COMPUTED TOMOGRAPHY (HRCT) OF SPONDYLYTIC SPONDYLOLISTHESIS G. BUIRSKI and I. W A T T Bristol Royal Infirmary

The demonstrat ion of partes defects may require multiple radio- graphic projections. High resolution computed tomography (HRCT) in the axial plane is however ideal to show both the posterior e lements and adjacent soft tissue structures.

H R C T appearances, using 4 mm vertically contiguous images, of 25 spondylolytic defects in 13 patients are reviewed, nine of whom had a Grade I spondylolisthesis.

An incomplete bony ring between the vertebral body, pedicles and laminae indicates a spondylolysis. Defects arc more horizontally orientated than the oblique facet joints, not concentric, and with no evidence of an articular cortex. Instead the surface is irregular with adjacent sclerosis. The width of the lytic gap is variable. Fragmenta- tion was seen in 11 defects and was always associated with listhesis and deformity of the canal, usually an increased A P diametcr with an ellipsoid shape to the thecal sac. Stenosis of the neural foramen was not dcmonstra tcd though lateral recess stenosis was evident in three patients.

Horizontal stacked images may erroneously indicate the degree of listhesis because of lumbar lordosis. Angled scans, or the use of the digital topogram, are accurate, however.

COLONIC ILEUS M. M c N A M A R A and A. C H A P M A N St James's University Hospital, Leeds

Twenty cases of colonic ileus (pseudo-obstruct ion of the colon) encountered in the past 5 years are detailed. All were acute clinical presentat ions simulating mechanical obstruction and each had an acute contrast enema examination for diagnosis. The clinical associa-

tions are discussed. The plain abdominal radiographic features are described and we emphasise the difficulties encountered in differen- tiating colonic ileus, particularly when localised, from large bowel obstruction. The usefulness of an acute contrast s tudy is stressed.

PRE-OPERATIVE CT STAGING IN LUNG CANCER D. G R A N T , D. E D W A R D S and P. G O L D S T R A W University College Hospital, London

CT scanning of the chest, abdomen and brain was per formed on 114 patients considered to be suitable for curative resection of non small cell carcinoma of the lung. The effect on surgical m a n a g e m e n t is assessed.

CT scanning of the thorax alone altered surgical m a n a g e m e n t in 37 patients. Additional scanning of the abdomen altered m a n a g e m e n t in a further two patients and extension of the examination to include the brain altered managemen t in one other patient.

The incremental yield of additional CT scans of the abdomen and brain is small but significant and raises important ethical and economic considerations.

DEVIATION OF THE SUPERIOR MESENTERIC ARTERY IN RETROPERITONEAL DISEASE B. M. C A R R I N G T O N and D. F. M A R T I N Medical School, Manchester

The value of displacement of the superior mesentcric artcry (SMA) as a marker for retroperitoneal disease is unknown and was studied in 244 consecutive abdominal computed tomography (CT) scans. Nineteen patients were excluded because of inadequate information. In 225 examinations (195 with intravenous contrast enhancement) anterior and lateral diplacement of the proximal SMA was assessed and correl- ated with the presence of retroperitoneal disease. Deviation beyond the left margin of the adjacent vertebral body was always associated with obvious disease but deviation to the right was virtually always normal. Minor SMA displacement was not reliably associated with disease. Where the SMA was displaced but the CT appeared normal clinical follow up on 40 of 41 patients revealcd disease in thrcc (7.5 %). Correlation of SMA position with disease entities showed that aortic aneurysms and lymphadenopathy caused variable displacement around the aorta, whereas displacement in pancreatic disease was more likely to be to the left.

SMA displacement alone is not a useful indicator of occult retro- peritoneal disease.

RELAPSING POLYCHONDRITIS AND ITS RADIOLOGICAL MANIFESTATIONS A. B O O T H , P. DIEPPE, P. G O D D A R D and 1. W A T T Bristol Royal Infirmary

Relapsing polychondritis is a very rare condition, of unknown aetiol- ogy, characterised by a chondrolysis with replacement of cartilage by fibrous connective tissue. There is a spectrum of clinical manifesta- tions, a variety of which may be present in any one patient. These include a nasal chondritis, involvement of the pinna of the ear leading to an eventual 'floppy ear ' , an arthropathy which predominantly involves the peripheral small joints, laryngo-tracheo-bronchial involvement, ocular manifestat ions, such as episcleritis, and cardio- vasct]lar complications such as aortic valve regurgitation.

The arthropathy is present in 80% of cases, and may be either erosive or non-erosive. We have recently evaluated four patients with this condition.

The principal clinical, histological and radiological features will be illustrated.

BARIUM ENEMAS ARE A HEADACHE E. K U T T , A. B O O T H , M. H A L L and J. VIRJEE Bristol Royal Infirmary

Picolax (Ferring Pharmaceuticals) is used routinely in the preparation for bar ium enemas. Headaches wcre noted to be a common complaint in patients and this study was under taken to at tempt to ascertain the c a u s e .

Multiple blood indices were measured in 41 patients on three separ- ate occasions. The first was as a baseline prior to the administration of Picolax, the second following the administration of Picolax and prior

554 CLINICAL RADIOLOGY

to a washout, and finally following the washout. Only the haemoglobin level was found to be consistently higher than baseline values in the 25% of patients with headaches. Dehydration is therefore postulated to be the cause.

THE PLAIN ABDOMINAL RADIOGRAPH IN ACUTE RUPTURE OF ABDOMINAL AORTIC ANEURYSMS C. F. LOUGHRAN Broadgreen Hospital, Liverpool

Mortality from ruptured abdominal aneurysms is high and this is probably related, in part, to the delay in diagnosis which may occur. Since the plain abdominal radiograph is sometimes performed in this condition we reviewed 31 such examinations of patients with a surgically proven aneurysmal rupture in order to determine what changes may be seen. Obliteration of the psoas or renal outlines occurred in 75% of patients, an abdominal soft tissue mass in 67%, renal displacement in 25% and properitoneal flank stripe changes in 19%. The diagnosis may be made from the abdominal radiograph in 90% of patients with this condition.

This presentation will illustrate the variety of radiographic signs that may be seen with particular attention directed towards the retro- peritoneal fat planes.

RADIOLOGY OF GASTROINTESTINAL CARCINOID C. R. MERRILL and N. D. BAX Royal HaUamshire Hospital, Sheffield

The experience of a regional centre with a particular interest in the carcinoid syndrome is presented. Forty-eight cases have been seen in 7 years, of which 15 involved the small bowel. This talk is focused on gastrointestinal carcinoid, especially where it differs from the 'classi- cal' textbook picture in either radiological appearance or mode of presentation. Intestinal obstruction and diarrhoea are the main pre- senting features. However, these can be episodic and the history of abdominal symptoms may go back several years in which time the patient usually has had multiple investigations. Most of these arc negative, often because the diagnosis has not been suspected clinically. Barium studies are the most helpful investigations but are by no means diagnostic. Precise diagnosis is important since patients may survive long periods despite having multiple metastases. In these cases tumour debulking or hepatic embolisation may give great symptomatic relief.

RADIOTHERAPY AND ONCOLOGY THE ROLE OF STEREOTACTIC RADIOSURGERY IN THE MANGEMENT OF INTRACRANIAL ARTERIOVENOUS MALFORMATIONS Chairman: Dr F. E. Neal

THE SHEFFIELD STEREOTACTIC RADIOSURGERY PROGRAMME - PAST AND PRESENT Mr D. M. C. Foster

DOSIMETRY AND DOSE PLANNING IN STEREOTACTIC RADIOSURGERY L. WALTON and C. K. BOMFORD Weston Park Hospital, Sheffield

In stereotactic radiosurgery, the beams of radiation from 201 separate and individually collimated Cobalt-60 sources are directed towards a common focal spot. The resultant effect is a well defined focus of high dose, with rapid dose fall off with distance from the focus.

The computation of the standard beam characteristics for the three available field sizes is described. The resultant distributions were verified, using an array of solid state dosimeters within a hemispherical tissue equivalent phantom. The position of the array of dosimeters was varied to measure the total distribution of dose around the focus.

The computation of the three dimensional distribution, around a lesion within the brain, is achieved by modifying the standard distribu- tions. Corrections are applied to take account of the orientation and shape of the head and also of the position of the lesion. Treatment plans for single and multiple field treatments can be produced.

THE STEREOTACTIC RADIOSURGERY UNIT IN SHEFFIELD J. D. BRADS.HAW Weston Park Hospital, Sheffield

The concept of radiosurgery was introduced by Professor Lars Leksell of Stockholm, in 1951, for the irradiation of small well-defined volumes within the intact skull, in single sessions, as an alternative to open surgery when this would be hazardous or impossible.

It was based on the use of a fixed array of multiple small well collimated beams of radiation, all focused at one point, the patient's head being held in a rigid frame which could be kept in a position such that the lesion to be treated coincided with the focal point of the radiation beams.

The Sheffield unit has 201 cobalt-60 sources, with final collimators which define beams of 4, 8 or 16 mm diameter at the focal spot. The initial activity of each source was 1040 GBq, making a total activity of 208 TBq. This results in treatment times of 10 to 20 min.

The unit became operational in September 1985, initially treating one patient each week, this being increased to two patients each week in June 1986.

Initially, arterio-venous malformations were treated using anglo- graphic localisation. Later, acoustic neuromas were treated using CT localisation, and other solid lesions will be treated if suitably small and well-defined.

STEREOTACTIC RADIOSURGERY IN THE PITUITARY REGION Prof. E. O Backlund

SCREENING AND M A N A G E M E N T OF GESTATIONAL TROPHOBLASTIC DISEASE 1973--85. THE SHEFFIELD EXPERIENCE Chairman: Dr J. D. Bradshaw

SCREENING AND MANAGEMENT OF GESTATIONAL TROPHOBLASTIC DISEASE. THE SHEFFIELD EXPERIENCE MARK DORREEN and DAVID R. MILLAR Weston Park Hospital & Jessop Hospital for Women, Sheffield

In 1973 three supraregional centres in London, Sheffield and Dundee were set up to monitor those women who had delivered hydatidiform moles. The North of England screening service now registers some 350 patients a year. Of these, approximately 5% are treated with chemo- therapy for invasive disease. In addition, the centre collects those cases of choriocarcinoma, which arise following abortion and viable pregnancy.

The screening programme and various chemotherapeutic regimes will be described. These have resulted in a cure rate of over 95% for choriocarcinoma.

One in six patients still have hysterectomy for their trophoblastic disease, either before or during chemotherapy. The surgical tech- niques for evacuating and diagnosing molar disease and the indications for major surgery, in the modern management of invasive trophoblas- tic neoplasia, will also be discussed.

RADIODIAGNOSIS WILLIAM COOK SYMPOSIUM ON INTERVENTIONAL RADIOLOGY Chairman: Professor R. G. Grainger (Sheffield)

VARICOCELE EMBOLISATION J. F. REIDY

OESOPHAGEAL DILATATION A. LUNDERQUIST, H. STRIDBECK, K. IVANCEV and C. LUNDSTEDT University Hospital, Lund, Sweden

Balloon catheter dilatation has been performed on patients with benign and malignant oesophageal strictures. Twenty-six patients with benign strictures had altogether 64 dilatations. One patient had the stricture dilated 12 times.

Seventeen patients with malignant stricture were referred for dilata- tion of the stricture either because of intended placement of an Atkin- son tube or to make biopsy possible.