UNCLE BRANTS HOUR/ AUNT MINNIES BY DR CHARLES LIM

this is uncle brants hour similiar to aunt minnies hour in which we flash different pathognomonic / must know signs or radiologic presentations to radiology residents in training to help them gain a memory bank on the must know signs and their corresponding diangoses.

1. BACK TO BASICS CLASSIC SIGNS IN THORACIC IMAGING ‘MUST KNOW’ CLASSICAL SIGNS

2. 1. AIR CRESCENT SIGN often seen in neutropenic patients who have undergone bone marrow or organ transplantation most characteristic of infection with invasive pulmonary aspergillosis considered a good marker of immune activity as it is seen when the necrotic tissue gets invaded by leukocytes and replaced by air OTHER CAUSES: cavitating neoplasms, bacterial lung abscesses , and infections such as tuberculosis or nocardiosis

3. BULGING FISSURE SIGN Klebsiella pneumoniae   infection due to large exudates produced  OTHER CAUSES: Hemophilus influenzae, tuberculosis, pneumococcal pneumonia, large lung abscesses, and lung neoplasms (bronchoalveolar carcinoma)

4. CERVICOTHORACIC SIGN used to differentiate between an anterior and posterior mass

5. COMET TAIL SIGN (ATELECTATIC PSEUDOTUMOR, FOLDED LUNG, OR BLESOVSKY SYNDROME) pulmonary vessels and bronchi toward a region of round atelectasis most commonly associated with asbestos-related pleural disease posterior aspect of the lower lobes, it may demonstrate significant contrast enhancement and contain air bronchograms OTHER CAUSES: tuberculosis, histoplasmosis, pulmonary infarcts, or congestive heart failure

6. CONTINUOUS DIAGPHRAGM SIGN pneumomediastinum helpful in differentiating from a pneumothorax can occasionally be also seen in pneumopericardium

7. CRAZY-PAVING SIGN pulmonary alveolar proteinosis thickening of interlobular septa superimposed on areas of ground glass opacification thick interlobular septa represent inflammation, while the ground glass opacities are due to intra-alveolar protein-rich fluid OTHER CAUSES: Pneumocystis carinii pneumonia, organizing pneumonia, usual interstitial pneumonia, non-specific interstitial pneumonia, and exogenous lipoid pneumonia, sarcoidosis, adult respiratory distress syndrome, pulmonary hemorrhage, and mucinous BAC

8. CT HALO SIGN In febrile neutropenic patients, the sign suggests angioinvasive fungal infection associated with a high mortality rate in the immunocompromised represents alveolar hemorrhage OTHER CAUSES: candidiasis, cytomegalovirus, herpes simplex virus, and coccidioidomycosis, Wegener granulomatosis, metastatic angiosarcoma, Kaposi sarcoma, and brochioloalveolar carcinoma (BAC)

9. DEEP SULCUS SIGN pneumothorax in a supine patient

10. DOUBLE DENSITY SIGN left atrial enlargement semiquantitative measurement to estimate distance from the midpoint of the double density to the inferior wall of the left mainstem bronchus, a distance greater than 7 cm (unreliable in pediatric patients) Atrial escape: project beyond the right atrium border  Look for other signs: carinal widening, elevation of the left main bronchus, and enlargement of the left atrial appendage

11. FEEDING VESSEL SIGN hematogenous origin of the nodule strong indication of septic embolism  OTHER CAUSES: hemorrhagic nodules, pulmonary vasculitis, pulmonary infarct, and pulmonary arteriovenous malformation

12. FINGER-IN-GLOVE SIGN represent dilated, mucoid-impacted bronchi surrounded by aerated lung Stenosis or obstruction -> mucous continue to produce fluid -> become inspissated and debris accumulates -> bronchiectasis pores of Kohn and canals of Lambert aerating lung distal to the point of mucoid impaction NON-OBSTRUCTIVE CAUSES: allergic bronchopulmonary aspergillosis (ABPA), asthma, or cystic fibrosis OBSTRUCTIVE : Benign (bronchial hamartomas or lipomas) and malignant (bronchogenic carcinoma or carcinoid tumors) neoplasms CONGENITAL : bronchial atresia, intralobar sequestration, or bronchogenic cysts

13. FLEISCHNER SIGN enlargement of the proximal pulmonary arteries secondary to pulmonary embolism KNUCKLE SIGN: abrupt tapering of the occluded pulmonary artery distally

14. HAMPTON HUMP When pulmonary embolism results in pulmonary infarction , airspace opacities typically develop within 12 to 24 hours In patients without heart disease, the incomplete infarcts would generally heal without scarring patients with congestive failure were more likely to progress to infarction with a persisting pulmonary scar

15. HILUM OVERLAY SIGN based on the Silhouette sign If the hilar vessels are sharply delineated, then it can be assumed that the overlying mass is anterior or posterior

16. JUXTAPHRENIC PEAK SIGN ( KATTAN’S SIGN) upper lobe collapse most commonly related to the presence of an inferior accessory fissure but can also be caused by major fissure or inferior pulmonary ligament Also seen: middle lobe collapse, and in cases of post upper lobectomy

17. NACLERIO’S V SIGN Pneumomediastinum first described by Naclerio in cases of spontaneous esophageal rupture but not specific for it

18. POLO MINT SIGN central filling defects represent the thrombus  could be seen in any vessel with thrombus, such as pulmonary artery, superior vena cava or portal vein Acute pulmonary embolism

19. SIGNET RING SIGN bronchiectasis, or irreversible, abnormal bronchial dilatation soft-tissue attenuation represents a pulmonary artery lying adjacent to the dilated bronchi peribronchial thickening, lack of bronchial tapering, and visualization of bronchi within 1 cm of the pleura, are all contributing findings confirming the diagnosis most often due to necrotizing viral or bacterial bronchitis also occur secondary to bronchial obstruction with subsequent mucus production, and pulmonary fibrosis or radiation-induced

20. SILHOUETTE SIGN For localizing a lesion

21. SPLIT PLEURA SIGN strong evidence of empyema Empyemic fluid fills the pleural space, resulting in thickening and enhancement of the pleura

22. THYMIC NOTCH SIGN Thymus WAVE SIGN: gentle undulations seen on the right border of thymus due to costochondral junction impressions SAIL SIGN: riangular -shaped inferior margin of the thymus mostly seen on the right side

23. VISCERAL PLEURAL WHITE LINE pneumothorax

24. WESTERMARK SIGN PULMONARY EMBOLISM typically signifies either occlusion of a larger lobar or segmental artery or widespread small vessel occlusion

25. DOUGHNUT SIGN presence of subcarinal lymphadenopathy Normal: ‘‘inverted horseshoe’’ configuration lymphadenopathy appears as a mass posterior to the bronchus intermedius and inferior to the tracheal bifurcation, completing the rounded hilar ‘‘doughnut’’ density

26. GOLDEN S SIGN RIGHT UPPER LOBE COLLAPSE ASSOCIATED WITH A CENTRAL MASS elevation and medial displacement of the minor fissure with proximal convexity of the fissure due to the mass creates the ‘‘reverse S’’ can be applicable to atelectasis involving any lobe

27. LUFTSICHEL SIGN left upper lobe collapse German for ‘‘air crescent’’ superior segment of the left lower lobe hyperinflates and fills the vacated apical space insinuating itself between the aortic arch and the collapsed left upper lobe creating a sharp outline, or periaortic lucency

28. SCIMITAR SIGN CONGENITAL HYPOGENETIC LUNG (SCIMITAR) SYNDROME signifies a Partial anomalous pulmonary venous return most commonly to the infradiaphragmatic inferior vena cava curved shadow extends inferiorly toward the diaphragm along the right side of the heart

29. TREE-IN-BUD SIGN Commonly endobronchial spread of Mycobacterium tuberculosis represents the mucous plugging, bronchial dilatation, and wall thickening of bronchiolitis and relates to viscous fluid blocking the intralobular bronchiole of the secondary pulmonary lobule small , peripheral, centrilobular soft tissue nodules connected to multiple contiguous, linear branching opacities OTHER CAUSES : Pneumocystis jiroveci (Pneumocystis carinii ) pneumonia and invasive pulmonary aspergillosis , (cystic fibrosis), malignancy (lymphoma), panbronchiolitis , and aspiration