1、Signs in Thoracic Imaging,Karuppasamy, K.1, Abhyankar-Gupta, M.1, Fewins, H.1, Curtis, J.21The Cardiothoracic Centre - Liverpool NHS Trust, 2Aintree University Hospitals NHS Foundation Trust, Liverpool, United Kingdom,KEY LEARNING OBJECTIVES,Signs in radiology represent characteristic descriptive pa
2、tterns of certain abnormalities. There are several such signs commonly associated with thoracic imaging. Clear understanding of what these signs mean helps the radiologists to interpret the images more effectively, provide a more precise prediction of an underlying pathology and avoid using lengthy
3、descriptions. We consider this poster to be useful as an educational tool for medical students, junior doctors and radiology trainees who can learn about the presence of these signs, understand what they stand for and register the images of those signs in their minds. It will also help to refresh th
4、e knowledge of radiologists.,Thoracix Radiologic Signs,Thoracix Radiologic Signs,1. Air bronchogram sign,Air bronchogram sign: Refers to the presence of air filled (patent) bronchi surrounded by air spaces filled with pus or fluid; simply indicates air space disease; e.g. pneumonia,2. Air crescent s
5、ign,Air crescent sign: Refers to the air surrounding a radio opaque material in a crescentric manner along both its inner and outer margins indicating cavitary disease; e.g. aspergilloma in an old TB cavity,3. Bulging fissure sign,Bulging fissure sign: Refers to the convex configuration a fissure ta
6、kes to accommodate an adjacent swollen/enlarged lobe; e.g. Klebsiella pneumonia,4. Comet tail sign,Comet tail sign: Refers to an unusual form of focal lung collapse simulating a mass (body of the comet) with distorted vessels and bronchi (tail of the comet) radiating towards hilum; asbestos exposure
7、 in 70%,5. Continuous diaphragm sign,Continuous diaphragm sign: Refers to presence of air between heart & diaphragm (pneumomediatinum) or within pericardium (pneumopericardium) making normally invisible parts of central dipahgram visible in continuation with both hemidiaphragms,6. Crazy paving sign,
8、Crazy paving sign: Refers to the combination of ground glass attenuation superimposed on a network of interlobular septal thickening giving it an appearance of a surface paved with slabs of differing shapes; e.g. alveolar proteinosis,7. CT angiogram sign,CT angiogram sign: Refers to the conspicuous
9、enhancing pulmonary vessels in a background of homogeneous low-attenuating consolidation relative to chest wall musculature; e.g. Bronchoalveolar cell carcinoma,8. CT halo sign,CT halo sign: Refers to a zone of ground-glass attenuation (the halo) surrounding a pulmonary nodule or mass; e.g. invasive
10、 aspergillosis,9. Deep sulcus sign,Deep sulcus sign: Refers to a deep lateral costophrenic angle on a supine CXR representing gas collection in a subpulmonary location due to pneumothorax and may be the only sign of it,10. Double density sign,Double density sign: Refers to an abnormal density overly
11、ing right heart border; the normal right heart forms its usual density and the abnormality forms the other density; e.g. left atrial enlargement,11. Fallen lung sign,Fallen lung sign: Refers to the collapse of lung away from the mediastinum when the normal central bronchial anchoring attachment of t
12、he lung is disrupted as in bronchial tear/fracture.,12. Figure 3 sign,Figure 3 sign: Refers to the abnormal contour of aortic arch in coarctation of aorta. The upper arc is the dilated arch proximal to the coarctation, the lower arc is the poststenotic dilatation & the indentation between the 2 arcs
13、 is the coarctation.,13. Fissure sign,Fissure sign: Normal separation of lobes by fissures is not seen in perfusion scans due to low resolution; but, increased separation due to pleural thickening or effusion is seen as linear area of reduced uptake along the fissure referred as fissure sign,14. Fla
14、t-waist sign,Flat-waist sign: Refers to the loss of concavity of the left heart border on a symmetrical frontal CXR due to slight anterior oblique rotation of the heart seen in some cases of left lower lobe collapse.,15. Fleischner sign,Fleischner sign: Refers to the prominence of central pulmonary
15、artery caused either by pulmonary hypertension that develops secondary to PE or by distension of the vessel by a large clot,16. Gloved finger sign,Gloved finger sign: Refers to the branching finger like opacities representing dilated bronchi filled with mucus (mucoid impaction) radiating from the hi
16、la towards the periphery; e.g. ABPA,17. Golden S sign,Golden S sign: Refers to a reverse S shaped shadow caused by right upper lobe collapse forming the upper curve of the reverse S (concave infero-laterally) and a central mass causing the collapse forming the lower curve (convex infero-medially),18
17、. Hampton hump sign,Hampton hump sign: Refers to a homogeneous wedge-shaped consolidation in the lung periphery with a base contiguous to a visceral pleural surface and a rounded convex apex directed toward the hilum; associated with pulmonary infarct,19. Headcheese sign,Headcheese sign: Refers to t
18、he combined presence of ground glass opacity, normal lung and reduced attenuation due to air trapping giving the lung a geographic appearance resembling the variegated appearance of a sausage made from head of a hog; e.g. hypersensitivity pneumonitis,20. Hilar overlay sign,Hilar overlay sign: Refers
19、 to the ability to see the hilar structures through the shadow of a mass superimposed on the hilum; indicates that the mass lies either in front or behind the hilum; e.g. anterior lymphoma or posterior neurofibroma,21. Luftsichel sign,Luftsichel sign: Refers to the paraaortic crescentric lucency cau
20、sed by the hyperexpanded superior segment of the left lower lobe in cases of left upper lobe collapse (German = Luft- air; sichel- crescent),22. Positive bronchus sign,Positive bronchus sign: Refers to the tubular area of hypoattenuation representing air filled bronchus leading to a peripheral nodul
21、e; If this extends into the nodule/mass, an air bronchogram sign in produced,23. Ring around the artery sign,Ring around the artery sign: Refers to the lucency caused by air around a vessel such as pulmonary artery; indicates pneumomediastinum,24. Scimitar sign,Scimitar sign: Refers to the curved va
22、scular shadow (resembling a short, curved Turkish sword called scimitar) representing an anomalous pulmonary vein draining the right lung that descends toward the diaphragm located to the right of the heart,25. Signet/pearl ring sign,Signet/pearl ring sign: Refers to the combination of a small soft
23、tissue attenuating circle (pulmonary artery- pearl on a ring) abutting a larger soft tissue attenuating ring (wall of a bronchus- ring); ring surrounds a low-attenuating circle (air within bronchus); indicates bronchiectasis,26. Silhouette sign,Silhouette sign: Refers to the inability to see the bor
24、der of a normal structure such as heart or aorta masked by an opacity of similar density anatomically contiguous with this border; e.g. right middle lobe consolidation masking right heart border,27. Split pleura sign,Split pleura sign: Refers to the two layers (visceral and parietal) of enhancing pl
25、eura split by the presence of an pleural inflammatory process such as empyema,28. Thymic sail sign,Thymic sail sign: Refers to the outlining of normal thymus by air which also elevates the thymus giving it the configuration of a sail; indicates pneumomediastinum,29. Tree-in-bud sign,Tree-in-bud sign
26、: Refers to the pattern of opacity seen in a HRCT; the terminal tufts of TIB represent inflammatory material filling respiratory bronchioles and alveolar ducts and the stalks of TIB represent filling within terminal bronchiole; e.g. Endobronchial TB,30. Westermark sign,Westermark sign: Refers to an
27、area of o!igemia with minimal change in lung volume distal to a large PE; this regional oligemia is caused either by mechanical obstruction to blood flow by the clot or by reflex vasoconstriction,CONCLUSION,We hope that this pictorial review with description helps the viewers to remember and recall
28、the signs during their practice.,ACKNOWLEDGEMENTS,We would like to thank Dr John Reynolds (Heartlands Hospital, Birmingham) for Fallen lung sign; Dr Irion Klaus (CTC, Liverpool) for Bulging fissure sign and Ring around the artery sign; Dr David Hughes (Arrowe Park Hospital, Wirral) for Hampton hump
29、sign, Headcheese sign and Westermark sign,REFERENCES,1. Marshall GB, Farnquist BA, MacGregor JH, Burrowes PW. Signs in thoracic imaging. J.Thorac.Imaging 2006;21:76-902. Webb WR. Thin-section CT of the secondary pulmonary lobule: anatomy and the imagethe 2004 Fleischner lecture.Radiology. 2006 May;239(2):322-383. Austin JH, Muller NL, Friedman PJ, Hansell DM, Naidich DP, Remy-Jardin M, Webb WR, Zerhouni EA. Glossary of terms for CT of the lungs: recommendations of the Nomenclature Committee of the Fleischner Society. Radiology 1996;200(2):327-31,
