Radiologic signs

Radiologic signs are specific imaging findings seen on various radiology modalities, including X-ray, Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and Ultrasound. These signs are crucial for the diagnosis and management of numerous medical conditions. They are named after their discoverers or because of the resemblance to certain objects or patterns. This article will discuss some of the most well-known radiologic signs, their significance, and the conditions they are associated with.

Air Bronchogram

An Air Bronchogram is a pattern seen on chest X-ray or CT scan where air-filled bronchi are made visible by the surrounding alveoli filled with fluid. This sign is indicative of lung pathology, such as pneumonia, pulmonary edema, or Acute Respiratory Distress Syndrome (ARDS).

Apple Core Lesion

The Apple Core Lesion is a term used in barium enema studies to describe a constricted section of the colon with shouldered edges, resembling an apple core. This sign is highly suggestive of colorectal cancer.

Bat Wing or Butterfly Pattern

Seen in chest X-rays, the Bat Wing or Butterfly Pattern refers to bilateral perihilar alveolar infiltrates that resemble the wings of a bat or a butterfly. This pattern is typically associated with pulmonary edema, especially of cardiogenic origin.

Bird Beak Sign

The Bird Beak Sign is observed in barium swallow studies of the esophagus. It describes the tapering of the distal esophagus in conditions like achalasia or esophageal cancer, resembling a bird's beak.

Cannonball Metastases

Cannonball Metastases refer to multiple, well-rounded opacities scattered throughout both lungs on chest X-ray or CT scan. This pattern is indicative of hematogenous spread of metastatic cancer, particularly from renal cell carcinoma or choriocarcinoma.

Halo Sign

In Computed Tomography (CT) of the chest, the Halo Sign describes a ground-glass opacity surrounding a nodule or mass, suggestive of invasive fungal infections like aspergillosis or malignancies.

Honeycombing

Honeycombing is a pattern seen on high-resolution CT of the chest, characterized by clustered cystic air spaces, usually at the lung peripheries. It is indicative of end-stage Interstitial Lung Disease (ILD) or Idiopathic Pulmonary Fibrosis (IPF).

String of Pearls Sign

The String of Pearls Sign is seen in MRI of the abdomen and refers to multiple, small, fluid-filled cysts in a row within a duct or tube, often associated with Sclerosing Cholangitis.

Sunburst Appearance

The Sunburst Appearance is seen in X-ray of the bone, describing the radiating spicules from a central point, suggestive of aggressive bone lesions like osteosarcoma.

Tram Track Sign

The Tram Track Sign can be observed in CT scans of the brain, representing parallel lines of calcification along the cerebral sulci, commonly associated with Sturge-Weber syndrome.