Identification of consolidation on chest images is a useful skill for radiographers. Care must be taken to not call every lung opacity a consolidation. There are a variety of causes of lung opacity and a number of known false signs. This page looks at some of the other consolidation-like appearances.

Case 1

This patient presented for chest radiography with "knowna ischaemichistory heartof diseaserecent andfacial chestnerve pain".palsy. There is loss of clarity of the right heart border suggesting RMLcardiac pathology.border.

There is no abnormal RML opacity. There is evidence of pectus excavatum (depression of the sternum). Pectus excavatum is a known cause of false RML disease and is likely to be a contributing cause of the pseudo-silhouette sign on the PA image. Other contributing factors could be pericardial fat (although none is seen in this patient) and overlying pulmonary vessel. Case 2 This patient presented for chest radiography with a history of recent facial nerve palsy. There is loss of the right cardiac border.The lateral chest X-ray image demonstrates a severe pectus excavatum deformity (arrowed). In these patients the heart tends to be displaced towards the left as a result of the limited space between the depressed sternum and the spine. The lossspine.Other ofcontributing thefactors rightcould heartbe borderpericardial onfat the(although PAnone imageis wasseen notin athis resultpatient) ofand aoverlying diseasepulmonary process.vessel. Pectus Excavatum http://en.wikipedia.org/wiki/File:Pectus1.jpg

Pericardial Fat

Validation of cardiovascular magnetic resonance assessment of pericardial adipose tissue volumeAdam J Nelson , Matthew I Worthley , Peter J Psaltis , Angelo Carbone , Benjamin K Dundon , Rae F Duncan , Cynthia Piantadosi , Dennis H Lau , Prashanthan Sanders , Gary A Wittert and Stephen G WorthleyCardiovascular Research Centre, Royal Adelaide Hospital & Disciplines of Medicine and Physiology, University of Adelaide, Adelaide, SA, Australia

This is a sheep's heart with the pericardium partly dissected off. Note the pericardial fat. Felson (Chest Roentgenology, W.B. Saunders, 1973, p55) notes that "For reasons that escape me, fat in the thorax is often impossible to differentiate from water density. Perhaps the adjacent pulmonary gas density has something to do with this illusion." This is an interesting point given the clear differentiaton between fat and water density structures seenin the abdominal plain film.

Case 1

This 49 year old female patient presented for chest radiography with "recent onset of chest pain". There is loss of clarity of the right heart border. In addition, there is loss of clarity of the left heart border. There are good reasons to consider that these silhouette signs are not caused by lung consolidation. The patients history and clinical signs do not suggest a diagnosis of infection/consolidation there is no evidence of alveolar opacity the lateral view does not demonstrate alveolar opacity that you would expect with a lung consolidation The likely cause of the loss of clarity of the cardiac silhouette is the presence of pericardial fat.

There is no abnormal RML or left upper lobe (lingula segment) opacity. Where there is a significant amount of pericardial fat visible on the PA/AP chest image, you would expect to see evidence of this on the lateral image (white arrow)

patient with minimal pericardial fat for comparison (ignore arrow)