Year : 2012  |  Volume : 15  |  Issue : 4  |  Page : 318--319

RE: Disappearing ring in chest cavity

Sivasubramanian Srinivasan 
 Department of Diagnostic Radiology, Republic of Singapore

Correspondence Address:
Sivasubramanian Srinivasan
Department of Diagnostic Radiology, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore 768228

How to cite this article:
Srinivasan S. RE: Disappearing ring in chest cavity.Ann Card Anaesth 2012;15:318-319

How to cite this URL:
Srinivasan S. RE: Disappearing ring in chest cavity. Ann Card Anaesth [serial online] 2012 [cited 2020 Oct 19 ];15:318-319
Available from:

Full Text

The Editor,

I read with interest the article, 'Disappearing Ring in Chest Cavity,' an interesting postoperative chest radiograph presented by the authors. [1] I agree that the ring shadow appears larger than the expected tip of the drainage tube in the left chest. However, it must be noted that during a conventional X-ray imaging the objects nearer to the X-ray tube appear larger than the actual size of the object, in this case the ring shadow of the tip of the tube. Discussion with a radiologist experienced in conventional radiography would be very helpful or an additional view may be considered (like a translateral horizontal beam radiograph) without much discomfort to the patient in the immediate postoperative period. This would have confirmed that the shadow was due to the chest drain tube, which would have been reassuring to the primary physician in-charge of the patient.

The radiographic differential diagnoses of a cavity/cavitary lesion (mentioned as ring opacity by the authors, which is not a correct term to use in the chest) [2] are well-mentioned by the authors and include abscess, pulmonary tuberculosis cavity, and hydatid cyst. In such cases, the lung parenchyma adjacent to the cavity usually show airspace opacification. The Hydatid cyst shows air inside only when it ruptures into a bronchus; otherwise it appears as a uniform opacity. In the radiograph shown, the wall of the apparent cavitary lesion is smooth and no adjacent lung changes are noted. Such a sharp image is only likely with a foreign body.


1Venugopal V, Mahadevan R. Disappearing ring in chest cavity. Ann Card Anaesth 2012;15:163.
2Hansell DM, Bankier AA, MacMahon H, McLoud TC, Müller NL, Remy J. Fleischner Society: glossary of terms for thoracic imaging. Radiology 2008;246:697-722.