#COMET TAIL ARTIFACT FREE#

Treatment and prognosisĪside from the possible risk of malignant transformation (see Associations above), multiple biliary hamartomas are a benign asymptomatic condition with no long-term consequences, and no treatment is required. Nuclear medicineĬholescintigraphy shows delayed uptake and delayed emptying of tracer within larger biliary hamartomas 12. Hamartomas show no diffusion restriction on DWI sequences 2,9,11. However, in ~90% of cases an occasional hamartoma can be found containing a mural nodule (fibrocollagenous stroma, see Pathology above) or rim (see above) that is T1 isointense and T2 intermediate, of which ~90% will enhance.

thin peripheral rim enhancement has been described (see below), this may represent compressed normal liver parenchyma 14,15.

depending on TE, may approach CSF-signal intensity.

T1: hypointense compared to liver parenchyma.

Only a limited number of the many lesions that are actually present can be seen as grape-like clusters of abnormal vascularity with contrast persisting into the venous phase 10. Occasionally an enhancing nodule or rim may be identified in a small number of lesions.

CTīiliary hamartomas are hypoattenuating and often show no enhancement 7. The appearances may mimic metastases (see ultrasound appearances of liver metastases).

8.6 163-166.The prevalence of multiple biliary hamartomas is ~3% at autopsy 1 however, prevalence on imaging is 10 mm) may appear hypoechoic or anechoic and comet-tail artifact may be seen 9. More research is needed to know whether this finding is clinically relevant, but the prospects are looking bright. However, visualizing abdominal A-lines in every quadrant is concerning for bowel perforation in the cases presented. Comet-tail artifacts: Deeper echoes attenuated with decreased width resulting in a triangular shape. It is unclear what role the identification of abdominal A-lines can play in patient management, as this can be a normal finding when loops of gas-filled bowel are adherent to the abdominal peritoneum. However, explicit knowledge of sonographic artifacts such as the reverberation artifact can identify unexpected emergent diagnoses. The sensitivity of ultrasound for these diagnoses will likely never be adequate to be used as a screening tool. Point-of-care ultrasound is not the test of choice to rule out necrotizing fasciitis, all foreign bodies, or bowel perforation. The patient is diagnosed with emphysemtaous cholecystitis and subsequently undergoes an uncomplicated cholecystectomy. A bedside ultrasound is completed as shown (Image 5). She appears well, without jaundice, but has a fever and a positive Murphy's sign. Gallbladder with several reverberation artifacts originating within the gallbladder wall.Ī 48-year-old female presents for right upper quadrant abdominal pain. Reverberation artifacts are useful in assessing the characteristic structures of tissues but. It is manifested as a tapering shape and decreasing width with depth of travel ( Fig.

A diagnosis of necrotizing fasciitis is made, and the patient is taken to the operating room for debridement. Comet tail artifact is a form of reverberation between two closely spaced reflectors and appears as bright lines along the direction of ultrasound propagation.

#COMET TAIL ARTIFACT FREE#

The radiograph confirms free air without retained foreign body. The ultrasound (Image 1) demonstrates an impressive reverberation, ring-down artifact, concerning for a retained metal foreign body versus free air. A bedside ultrasound is performed, followed by a plain radiograph. His right arm demonstrates evidence of significant cellulitis and possible abscess near the antecubital fossa. You suspect the patient is intoxicated from methamphetamines. 1Ī-lines are part of the normal sonographic thoracic exam, but reverberation artifacts in other anatomic regions can be pathologic and point toward life-threatening diagnoses.Ī 38-year-old male presents with worsening arm pain and swelling. Another example of reverberation artifact is known as ring-down artifact and typically originates from small metal objects or air bubbles. Comet tail artifacts are another type of reverberation artifact originating from the pleural surface. A-lines are the reverberated ultrasound waves that have bounced between the parietal and visceral pleura. A common example is the “A-lines” visualized on thoracic ultrasound. Reverberation artifacts occur when two interfaces with high acoustic impedance bounce the ultrasound waves between them. Reverberation artifact originating from the patient's upper extremity soft tissue.