Clin. RadioL (1968) 19, 457-458

A N A N G I O G R A P H I C S I G N OF P E R S I S T E N T D U C T U S A R T E R I O S U S

BASIL STRICKLAND

From the Westminster and Brompton Hospitals, London

If associated with some other congenital cardiac defect a small persistent ductus arteriosus may be overlooked during angiocardiography when the catheter tip has been placed within the right ventricular cavity for the injection of the contrast medium. No cine' film may be taken and the only pictorial record will be on large films, usually in two planes via an Elema Roll Film changer. The lack of cine' film may remove the 'blanching' or 'piston' sign which is such a classic feature of the cine' diagnosis of a ductus. The simultaneous filling of the Aorta and Pulmonary Artery will be of no diagnostic value in the presence of a sizeable ventricular septal defect (i.e. alone or in Tetralogy of Fallot) and a small duct is often "lost" when the injection is made in the right ventricle. There may be a little irregular penumbra at the upper border of the main pulmonary artery especially on the A.P. films, but if this is the only indication of the possible presence of a ductus, then any additional evidence may be of value in diagnosis.

On many occasions the writer has observed differential filling of the peripheral branches of the

two pulmonary arteries in the angiographic series in the A.P. plane (Figs. 1 and 2)--i.e. on the first few frames the filling of the left lung tags quite noticeably behind the filling of the arterial tree on the right, but thereafter the filling of the two sides may become equal or may retain the discrepancy until contrast enters the aorta. This is clearly an extension of the 'blanching' sign in the main pulmonary artery (and observed to extend into the left main pulmonary artery on occasion) and is possibly due to the axis of flow of blood from the aorta into the pulmonary artery diluting the contrast. Conversely the frequent absence of the sign may be due to the presence of a very small or balanced shunt through the duct, or the site of in- sertion of the duct in the pulmonary artery i.e. if the insertion is central in the main pulmonary artery the dilution effect may not be seen. It is possible that the writer's explanation is incorrect since ducts inserted into the right pulmonary artery should show "dilution" on the right, but this has not been observed so far. In itself the sign is of no great significance but, in the complicated]circumstances

"F~. 1 457

458 C L I N I C A L R A D I O L O G Y

FIGS. 1 AND 2 Two gross examples of differential contrast filling of the peripheral branches of the left pulmonary artery. Usually the lack of contrast on the left is far less obvious but even when minimal it should raise the suspicion of persistent ductus

arteriosus as an associated lesion.

o u t l i n e d a b o v e it m a y be r e g a r d e d as o f s o m e ous re fe rence to this o b s e r v a t i o n can be f o u n d in t he m o m e n t w i t h i n its very l imi ted con tex t . N o prev i - l i tera ture .

N O T I C E S

CHRISTIE HOSPITAL AND HOLT RADIUM INSTITUTE

VISITOR'S COURSES

ONE week Visitors' Courses are held at the Christie Hospital twice a year, in November and May. These courses are primarily intended for visitors from this country and overseas who already have some knowledge of radiotherapy but who wish to see current methods and techniques being used in Manchester. They may be useful for D.M.R.T. and F.F.R. examination candidates but are not meant to be revision courses for either examination. During these courses there will be a full programme of talks, discussions and demonstra- tions by all the consultant radiotherapy staff of the hospital, which will include all the common varieties of disease treated by radiotherapy. The formal course will last five days beginning on the first Mondays in November and May. Visitors may, if they wish, remain for one further week to attend normal Out-patient, x-ray therapy, Radium Theatre and Mould Room work.

No fee is asked for these courses but numbers will be

limited. Prospective visitors are asked to write to Dr. E. C. Easson, Director of Radiotherapy, Christie Hospital, Withington, Manchester, 20, preferably at least one month in advance for further particulars.

THE USE OF COMPUTERS IN RADIOLOGY

SEPTEMBER 1969

The Royal Belgian Society of Radiology, under the auspices of the European Association of Radiology, is organising a Colloquium on this subject to be held in Brussels during September 1969. Members of the Institute have been invited to participate and anyone wishing to present a paper should contact the British Liaison Officer, Dr. Margaret Snelling at the Middlesex Hospital, London W.I.