GIT Imaging

Simplified Gastrointestinal Imaging

APP CONTENTS:

1-ESOPHAGUS

2-STOMACH_DUODENAL

3-COLON

ETC

Over the years, radiologists have established many classic imaging signs that represent visual manifestations of myriad underlying pathophysiologic processes. Though many of these signs were initially described on plain films, they are still used daily by radiologists reviewing images from cross-sectional modalities. For example, classic plain-film signs, such as the “accordion sign,” are also commonly cited today when seen on multidetector CT (MDCT) images.

The names of many classic radiologic signs derive from analogues to objects commonly encountered in everyday life; eg, the “comb” sign. The use of familiar objects to describe visual findings enables radiologists both to arrive at a correct diagnosis and to effectively convey such diagnostic findings to clinicians.

The goal of this article is to review an array of classic signs associated with gastrointestinal tract pathologies whose imaging manifestations resemble everyday objects. The “football” and “cobblestone” signs, for instance, are especially well known to the authors in Boston.Signs that do not conjure a resemblance to familiar objects, such as the “moulage” and the “colon cut-off” signs, are not covered. This article organizes the gastrointestinal signs from proximal to distal within the gastrointestinal tract. The hepatobiliary and pneumoperitoneum signs are then reviewed.

Bird’s beak sign

The “bird’s beak” sign is a classic finding on esophagrams; it describes a dilated proximal esophagus with a smooth-tapered, distal esophagus at the level of the esophageal hiatus in the setting of achalasia.1 The smooth tapering of the distal esophagus resembles the beak of a bird (Figure 1). On imaging and manometry, achalasia is further characterized by esophageal aperistalsis and failure of the lower esophageal sphincter to relax.

There are both primary and secondary forms of achalasia. Primary achalasia, the more common etiology, is idiopathic. The lack of lower esophageal sphincter relaxation is likely due to a loss of inhibitory neurons in the esophageal myenteric plexus. Proposed causes include neuronal degeneration, viral infection, genetic inheritance, and autoimmune disease.2 Secondary achalasia affects patients much less commonly and can be caused by entities such as esophageal carcinoma and Chagas disease.

Corkscrew sign

The “corkscrew” sign is the visual manifestation of lumen-obliterating, simultaneous, nonperistaltic contractions within the esophagus.

These abnormal contractions of varying amplitude occur in diffuse esophageal spasm, a rare esophageal motility disorder.3 Diffuse esophageal spasm is characterized on manometry by periods of normal peristalsis followed by simultaneous, repetitive, ineffective contractions. These abnormal contractions segment the normal esophageal lumen, mimicking a corkscrew on barium studies of the esophagus (Figure 2).4

Double-barrel esophagus

Intramural esophageal dissection is most commonly seen in middle-aged or elderly women. This entity can occur in the setting of a coagulopathy, emetogenic injury, trauma, instrumentation, ingestion of foreign bodies and, rarely, spontaneously.7 The double-barrel esophagus appearance can also be seen with intramural esophageal abscess, intraluminal diverticulum, or esophageal duplication.6

Bull’s eye lesions

etc