|RADIOLOGY OF CHEST A BRIEF REVIEW
|P Chandrasekhar: NTI Newsletter 1986, 22, 89-94.
Radiography is a commonly used diagnostic tool
for diagnosis of tuberculosis. It is still widely believed that
tuberculosis of the lung can be diagnosed by chest radiography alone.
However, practical experience and number of studies have proved
beyond doubt that no radiographic picture or pattern is absolutely
diagnostic or typical of tuberculosis. There are many conditions
of the lung which show similar radiographic appearance and can easily
be mistaken for tuberculosis. On the otherhand, in a substantial
percentage of bacteriologically confirmed cases, radiological picture
either did not show a shadow or was judged as non- tuberculosis.
Lesions being hidden behind other shadows e.g., of the ribs etc.
may be one of the reasons. A comparison of large X-ray with MMR
indicates that large X-rays are easily readable and have
low radiation dose but are more expensive and occupy more
space. The paper critically discusses the reliability of chest radiography
also. The concluding remarks are as follows: 1) 20% of lung fields
are hidden behind bones, heart, soft tissues, etc. 2) Activity of
an X-ray lesions cannot be determined on the basis of single X-ray
picture. Even sequential X-rays or repeated serial X-rays of the
patient over a period of time have their limitations and is not
fool proof. 3) Inter-individual and intra- individual variations
in interpretations seriously affect the diagnosis. Both over reading
and under-reading are substantial. The latter can be improved to
some extent by constant practice and experience in X-ray reading
but cannot be eliminated entirely.
|KEY WORDS: CHEST RADIOLOGY, X-RAY DIAGNOSIS.