Type:
Educational Exhibit
Keywords:
Pathology, Artifacts, Abscess, Perception image, Education, Ultrasound-Colour Doppler, Ultrasound, Ultrasound physics, Emergency, Abdomen
Authors:
G. A. Averanga Ticona, Z. FIGUEROA MARQUEZ , G. G. Leal, Y. P. Narváez Rojas, F. A. Abramzon, J. Crosta; Buenos Aires/AR
DOI:
10.26044/ecr2019/C-2690
Background
Ultrasound is widely recognized as a tool in bedside diagnosis in patients with emergency pathology,
especially in the acute abdomen (1,2).
Initial evaluation of the peritoneal patient often includes a bedside FAST exam to document the presence of free fluid (3).
Traditional teaching highlights the diagnostic utility of free fluid, as a significant finding (Search for an aortic aneurysm or broken ectopic pregnancy) and as a desirable complement for better ultrasonographic imaging (such as filling the bladder for pelvic imaging) (3).
In contrast,
intra-abdominal air is commonly 'tolerated' as a necessary evil that often frustrates adequate image acquisition.
In contrast to its presence in other diagnostic modalities such as tomography and conventional radiography.
(Fig. 1)
Fig. 1: A. The liquid is used as a desirable complement for the acquisition of images. B. While the air is a necessary evil that frustrates the adequate obtaining of images
Against this fact,
there are several published studies that suggest techniques and document the successes and accuracy of ultrasound for the diagnosis of the presence of air where it should not be (4,5).
Despite this,
many textbooks and teachers,
especially those related to emergency ultrasonography and critical care,
skip the subject completely,
limiting the scope of ultrasonography,
as an initial diagnostic method.
The inclusion of the search and evaluation of the pathological air will increase the diagnostic performance of the ultrasound of the head of the acute abdomen.
Radiologists should become familiar with the findings and techniques to acquire the necessary experience and make the diagnosis with confidence.
Air is a medium that has high resistance and impermeability to ultrasound waves,
so it is a strong reflector of them.
When it is in considerable quantity,
it generates the artifact in "Ringdown" that is usually accompanied by the "Dirty acoustic shadow". (Fig. 2)
Fig. 2: HEPATIC ABSCESS SECONDARY TO NEOPLASIA. The presence of the Artifact in Ringdown is observed that is usually accompanied by a dirty acoustic shadow