Correct!
4. Crazy-paving pattern
The appearance of smooth interlobular septal thickening and intralobular lines superimposed on a background ground-glass opacity, often with a geographic appearance of abnormal lung sharply demarcated from uninvolved lung, has been referred to as the “crazy-paving” pattern. The “finger-in-glove’ sign, a term often applied at chest radiography, represents a tubular opacity resulting from bronchial impaction, often in the context of allergic bronchopulmonary aspergillosis. The CT angiogram sign represents the appearance of enhancing vessels within low attenuation consolidation at CT. Initially thought to suggest the presence of malignancy, particularly mucinous bronchogenic malignancy, this sign is very non-specific and can be seen in a wide variety of conditions. The “reverse ground-glass halo” [or “reverse halo”] sign and “atoll” sign refer to the same CT finding- a focal rounded area of ground-glass opacity surrounded by a complete or incomplete ring of consolidation. Initially thought to be specific for the presence of organizing pneumonia, this sign is still suggestive of that entity but can be seen in a number of other conditions, including infections and vascular insults.
Which of the following represents the most appropriate differential diagnostic consideration for the appearance at CT? (Click on the correct answer to be directed to the eleventh of fourteen pages).