(1)
Hôpital Ambroise Paré Service de Réanimation Médicale, Boulogne (Paris-West University), France
Some artifacts are useless, others life-saving. The idea of suppressing all of them without discrimination is questionable. Technologies which will keep lung rockets alive will obviously keep alive the others, therefore, this short chapter. It intends to clarify the minds, describing all what can be encountered in the human being. Nothing is completely simple in medicine, and we aimed, in alphabetical order but some logic too, at decreasing the effort of memory. Remember that only two have a major clinical relevance, A-lines and B-lines (Fig. 40.1):
Fig. 40.1
Filiation between comet-tail, B-lines, and lung rockets. The main thoracic artifacts. This figure shows the scientific filiation between names sometimes confused in the brains. Lung rockets are a certain kind of B-lines. The B-line is a certain kind of comet-tail artifact. This figure aims at showing that lung ultrasound is a simple discipline, where confusions should not exist once the field has been standardized
A-lines (A for the first letter)
Lung
Horizontal hyperechoic artifacts arising from the pleural line at regular intervals which are equal to the skin-pleural line distance – indicating physiologic gas as well as free gas– as shown in Chap. 9.
A1, A2, etc., lines: Number of A-lines arising from the pleural line (not a very useful data).
B-lines (B for the second letter, also because this label is culturally linked to interstitial syndrome for the past 80 years. We specify in fact “ultrasound B-lines”) shown in Chap. 11
Lung
Artifacts defined according to seven criteria:
A.
Constant criteria:
1.
Comet-tail artifacts
2.
Arising from the pleural line
3.
Moving with lung sliding
B.
Almost constant criteria:
4.
Well defined, laser beam-like
5.
Long, not fading
6.
Erasing A-lines
7.
Hyperechoic (like the pleural line)
b-line: one B-line visible between two ribs. The term b-line is always singular.
bb-lines: two B-lines.
B+ lines: three or more B-lines, again, visible between two ribs.
Septal rockets (ex-B7-lines): B+ lines separated in adults by 6–7 mm, i.e., the distance between two interlobular septa (interlobular septal thickening). Between two ribs, usually 3 or 4 B-lines.
Ground-glass rockets (ex-B3-lines): B+ lines separated in adults by 3 mm, i.e., twice as many B-lines, possibly explained by extreme cases of interstitial syndrome. They are correlated with CT ground-glass lesions.
Birolleau variant: so many B-lines that the Merlin’s space appears homogeneously hyperechoic.
Sub-B-lines: see below.
C-lines (like centimetric cupuliform consolidation) shown in Chap. 17
Lung, real image (the exception in this chapter)
Curvilinear centimetric piece of alveolar consolidation abutting the pleural line. “Pleural-based” small lung consolidation, in other words.
D-lines
Available space
E-lines (for emphysema) shown in Chap. 14
Subcutaneous tissues
Comet-tail artifacts laser-like, hyperechoic, and spreading to the edge of the screen, but arising not from the pleural line, but from a hyperechoic line horizontally located above the pleural line (erased by these E-lines). Stripe of subcutaneous emphysema. No bat sign is visible: we are not in lung ultrasonography.
F-lines (from Fabien Rolland, a CEURFer)
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F like Fantôme (ghost) also. Designates all these punctiform or oblique lines sometimes found in the Merlin’s space at normal lung surface and mimicking, for novice eyes, air bronchograms (Fig. 40.2).
Fig. 40.2
F-lines, GB-lines, and H-lines. F F-lines. These hyperechoic punctiform artifacts, if standstill whereas a lung sliding is identified, have no other meaning than parasites – and should never be confused with air bronchograms. Such “air bronchograms” should be very static. Very because not only they do not show the pattern of the dynamic air bronchogram, but above all because they do not move, whereas lung sliding is identified. Real air bronchograms should follow lung sliding. In addition, the Merlin’s space never displays a shred sign in these cases (nor a frank tissue-like sign or the mediastinal line): all signs of lung consolidation. GB No bat sign? This is not lung ultrasound. It helps however in workshops, on occasion. GB-lines are abdominal artifacts, possibly indicating jejunal loops. H H-lines. When the probe lies on its stand, horizontal hyperechoic lines are generated, remember from far to the A-linesRelated posts:
The Excluded Patients of the BLUE-Protocol: Who Are They? Did Their Exclusion Limit Its Value?
The BLUE-Protocol and the Diagnosis of Pneumonia
Glossary
The Ultrasound Approach of an Acute Respiratory Failure: The BLUE-Protocol
The BLUE-Points: Three Points Allowing Standardization of a BLUE-Protocol
Which Equipment for the BLUE-Protocol 2. The Probe
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