The galaxy sign represents coalescing granulomatous inflammation in sarcoidosis. Large nodules with surrounding micronodules are characteristic – even pathognomonic – of sarcoidosis.
Two patients with sarcoidosis demonstrating the galaxy sign:
“Large Coalescent Parenchymal Nodules in Pulmonary Sarcoidosis: “Sarcoid Galaxy” Sign.” Am J Roentgenol 2002.
Black Hole Sign
Patients with angioinvasive fungal pneumonia caused by Mucormycosis develop necrotizing infarction of the lung parenchyma. This portion of the parenchyma will be completely non-enhancing at MRI and appear as a ‘black hole.’
We have collected several cases from our institution of proven CoVID-19 disease. The majority of these display typical imaging manifestations: on chest radiograph, either diffuse interstitial opacities or peripheral airspace opacities; on CT, peripheral predominant ground glass or consolidative opacities.