Lead V7 is on the left posterior axillary line in the fifth intercostal space, lead V8 on the left side of the back at the tip of the scapula and V9 on the left paraspinal line
in the fifth intercostal space) .
Plain radiograph of dorsal spine AP view revealed well-defined homogeneous opacity in left paraspinal region at D5/D6 level obliterating the left paraspinal line
and forming obtuse angle with the left lung parenchyma.
The absence of certain signs may help in excluding the diagnosis: loss of the aorticopulmonary window, abnormality of the aortic arch, rightward tracheal shift, and widening of the left paraspinal line
without associated fracture.
Furthermore, there was absence of the azygo-oesophageal line and bilateral paraspinal lines
. The lateral CXR revealed a posterior mediastinal mass.
Slightly overpenetrated films allow better visualisation of the thoracic spine, paraspinal lines
and aortic outline F Films for comparison Reviewing old films on the same patient may be helpful ABCDEF is a mnemonic to remember a systematic way of going through chest radiographs.