| 
                David Letterman Sign-widening of distance between  the scaphoid and lunate (>3mm) on PA view from ligament disruption-AKA Terry Thomas sign  | 
              
              
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                Dense MCA Sign-early CT sign, <6hrs, of  ischemic stroke seen with thrombosis of the middle cerebral artery; false +  findings may occur  | 
              
              
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                Double Bubble Sign-dilated stomach and proximal  duodenum in newborn, typically seen in duodenal atresia, midgut volvulus or  annular pancreas  | 
              
              
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                Double Density Sign-overlapping of an enlarged  left atrium and the normal right atrium on a frontal chest radiograph  | 
              
              
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                Doughnut Sign-in nucs, radiotracer uptake  surrounding a photopenic testis in testicular torsion; in GI CT, thickening of  the bowel wall  | 
              
              
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                Dense Hilum Sign-appearance of hilum which is  neither enlarged nor calcified implying superimposed lung density  | 
              
              
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                Draping Aorta Sign-blood that has leaked from the abdominal aorta  | 
              
              
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                Deep Lateral Sulcus Sign-abnormally deep depression of the lateral condylopatellar 
                  sulcus which can be an indirect sign of an ACL tear | 
              
              
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                Deep Sulcus Sign-inferiorly depressed  costophrenic angle from pneumothorax seen on supine radiograph of chest  | 
              
              
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                Double Bronchial Wall Sign-air outlining the trachea and  proximal bronchi in pneumomediastinum  | 
              
              
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                Drooping Lily Sign-appearance of lower pole  calyces in a duplicated collecting system with a non-functioning upper pole  | 
              
              
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                Double PCL Sign-low signal band parallel to  PCL produced by fragment of meniscus in bucket handle tear on knee MRI   | 
              
              
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                Double Duct Sign-dilatation of both the common bile duct and pancreatic duct on cross-sectional imaging, mostly by ca of pancreatic head or ampulla of vater  | 
              
              
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                Double Track Sign-UGI-redundant mucosa separates barium into two columns  in pyloric channel in hypertrophic pyloric stenosis  | 
              
              
                 | 
                Dripping Candle Wax Sign-cortical hyperostosis on one  side of bone likened to melting wax, seen in melorheostosis  | 
              
              
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                Dromedary Hump Sign-cortical bump on lateral  aspect of left kidney caused by compression by adjacent spleen  | 
              
              
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                Drooping Shoulder Sign-inferior subluxation of shoulder from hemarthrosis or flaccid paralysis  | 
              
              
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                Dagger Sign-dense line caused by  ossification of supraspinous and interspinous ligaments in ankylosing spondylitis  | 
              
              
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