Hosting 728 files, 2951 images, and 4 contributors.

Random Case

Jejunal Duplication Cyst
Joseph Junewick, MD FACR
over 10 years ago
Enter A Workflow
Standard2   Academic2

Please choose a workflow. A standard workflow allows you to browse the repository with full case detail; the academic workflow allows you to browse the repository with limited case detail revealed. Double click on the images to launch image viewer.

ARSt Case Repository

Inspissated Bile, Comet-Tail Artifact

Case Detail

Anatomy: Gastrointestinal
Joseph Junewick, MD FACR
Diagnostic Category: Radiation Safety-Physics
Created: over 10 years ago
Updated: over 10 years ago
Tags: PEDS
Modality/Study Types: US
Adobe32 PDF Imagej32 ImageJA


2 week old infant with recently repaired diaphragmatic henia and increasing bilirubin.

Case Images


Inspissated Bile, Comet-Tail Artifact


US – Numerous intraluminal hyperechoic foci with comet-tail artifact.


Comet-tail and ring-down artifact both appear as a series of parallel bands radiating from their source. Although similar in appearance, these artifacts have a different cause.

Ring-down is a common US artifact associated with transient gas collections. It appears as a series of bands or a solid streak radiating from the gas collections. This artifact originates at the center of a cluster of four aim bubbles (bubble tetrahedron). Entrapped between the bubbles is a horn-shaped fluid collection that returns a continuous sound wave when struck by an ultrasound pulse, analogous to striking a bell with a hammer. The mechanism producing the ring-down artifact is likely resonance.

The comet-tail artifact has a similar appearance to that of the ring-down artifact and has been associated with foreign bodies, particularly metallic objects, and calcifications. The comet-tail appearance is caused by reverberation of the ultrasound pulse within the material with the parallel bands closely spaced in the image because of the high acoustic velocity of the material.

Biliary stasis and inspissation increase formation of cholesterol crystals. This is commonly seen in the newborn period, especially in the setting of co-morbid conditions and recent surgery. Also as transducer frequency increases the more the cholesterol crystal interfaces reflect the sound beam. This results in more conspicuous comet-tail artifcact.


Shapiro RS, Winsberg F. Comet-tail Artifact from Cholesterol Crystals: Observations in the Postlithotripsy Gallbladder and an in Vitro Model. Radiology (1990); 177:153-156.


Linda Woolpert, RRT RDMS

Corporate Office: 616.363.7272, 3264 North Evergreen Drive, Grand Rapids, MI 49525

Spectrum Health Helen Devos Childrens Hospital GE HealthCare