Minerva
BMJ 2001; 322 doi: https://doi.org/10.1136/bmj.322.7285.564 (Published 03 March 2001) Cite this as: BMJ 2001;322:564All rapid responses
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Dear Sir,
We are saddened to note that Minerva, yet again, has chosen to
publish (BMJ 3.3.01) a description of a radiological image without a
radiologist as one of the authors. On this occasion, however, Minerva's
omission is not merely a sleight to radiologists, but has resulted in
erroneous information being printed in the British Medical Journal. No
pleural effusion of the size shown on the thoracic CT scan could fail to
be detected by a radiologist on a plain chest radiograph taken on the same
date (unless the plain film were of such poor technical quality as to be
undiagnostic). We note that you have omitted to publish any corresponding
plain film so this fact cannot be verified by your readers.
Based upon
routine daily experience, it comes as no surprise to us that a non-
radiologist clinician has interpreted a plain chest radiograph
incorrectly. We would be very happy to comment upon the corresponding
plain chest radiograph if it can be sent to us! The pleural effusion may
have been subpulmonary in position if the chest radiograph were taken
erect, and if the chest radiograph were taken supine, the pleural effusion
would have appeared as a uniform subtle increase in density over the right
lung. These are possible reasons why a non-radiologist clinician may have
misinterpreted the chest film.
Yours faithfully,
Dr Nicola H. Strickland
BM BCh, MA Hons (Oxon) FRCP (Lond) FRCR
Consultant Radiologist/Senior Lecturer, Hammersmith Hospitals Trust
Professor Jamie Weir
MB BS (Lond), FRCP (Ed), FRCR, FRANZCR
Consultant Radiologist/Professor of Radiology, Grampian University
Hospitals
Competing interests: No competing interests
Editor - I was fascinated by the allegedly invisible pleural effusion
described in this week's Minerva. I have lost count of the number of times
a referring physician or surgeon has attempted to enlist my enthusiasm for
yet another diagnostic test with the immortal phrase "...and the
CXR/AXR/SXR etc etc...was completely normal. Not infrequently, review of
the film in question reveals abnormalities which are clearly visible to
the trained observer. I suspect the same would have been true in this
case.
The authors do not mention whether the CXR had been formally reported
by the radiology department, nor do they mention the time interval between
the CXR and the CT scan. I do not believe that 3 litres of fluid was
invisible on the original plain film - instead I think it more likely that
the signs of a subpulmonic effusion (well known to radiologists but often
less well appreciated as an entity by clinicians), would have been present
but not recognised.
It would have been wise for the authors to have published the CXR
alongside the CT (and clearly the editorial process should have
recommended this), or - at the very least - to have added weight to their
assumptions by including a radiological co-author.
Finally, before our CT departments are flooded with unnecessary
requests to "rule out subpulmonic effusion", can I suggest that a simpler
method is to request a decubitus chest film which will immediately render
any pleural fluid (subpulmonic or otherwise)plainly visible.
Competing interests: No competing interests
It is indeed a interesting case report but would the time interval
between the chest radiograph and the CT scan make any contribution to the
picture?. It would also be interesting to know if the patients symptoms
were worse or same at the time of doing the CT and if a repeat chest
radiograph was performed or should it be performed just prior to the CT?
Competing interests: No competing interests
The image of the right pleural effusion on CT certainly demonstrates
the problem, but from the radiological point of view, it would also have
been useful to demonstrate the normal chest radiograph. Subtle signs of a
slightly raised right hemi-diaphragm, slight increase in density of the
right lung field and blunting of the right costo-phrenic angle are
important not to miss and I would have valued the chance to review the
normal film. However, the important learning point that a normal imaging
test does not exclude significant pathology is well emphasised.
Competing interests: No competing interests
Making the role of chest radiograph appear doubtful without valid consideration was disappointing
Editor-Blundell et al presented a case of dyspnoeic patient allegedly
due to 3 litres of pleural effusion, which was seen on computed tomography
(CT) scan of the chest but not on the chest radiograph.1 Several factors
need to be considered before jumping into any conclusion.
Firstly, small amount of pleural fluid may be missed on the chest
radiograph, but not the amount of fluid sufficient to cause breathlessness
on its own, unless associated with some other pathology. There could be
subtle signs like blunting of costophrenic angle or apparent raised
hemidiaphragm due to subphrenic collection even with mild effusion.
Secondly, pleural effusion on the lying (not erect) chest radiograph may
just cause mild hazziness on the whole side, as the fluid gravitates
posteriorly evenly and be easily missed. Thirdly, pleural fluid can
rapidly accumulate within a few days. One cannot compare the chest
radiograph and CT scan of the chest taken on different days. Finally it is
also important to consider whether the 3 litres of pleural fluid mentioned
was the amount drained in the first place itself or the total amount over
days. Because the irritation due to the chest drain and subsequent
exudation also adds to the amount drained later.
Thus in the case reported the chest radiograph should also have been
shown mentioning the time difference and the position of the patient. The
chest radiograph is an easily available and repeatable cheap investigation
associated with minimum radiation hazard. We should carefully consider
every aspect before making its role appear doubtful in a common condition
like pleural effusion.
1. Blundell A, Fyfe D, Woll PJ (Minerva). BMJ 2001;322:564. (3
March.)
Competing interests: No competing interests