2 days ago
👨💻The bowel wall shows a stratified morphology consisting of 5️⃣ concentric rings⭕️of alternating echogenicity referred to as the 👉”GUT SIGNATURE”✍️
👨💻Each of the rings seen at US examination corresponds to a different layer of the bowel wall seen at histologic analysis. US is the only imaging modality that can depict these histologic layers, which makes it particularly useful in bowel evaluation.
👨💻The innermost component of the gut signature is an echogenic line that represents the interface between the bowel lumen and the gut mucosa. This line is commonly referred to as the mucosal layer, despite the fact that it actually is an interface between the mucosa and the intraluminal bowel contents. Adjacent to this is a thin hypoechoic ring corresponding to the muscularis mucosa. Peripheral to the muscularis mucosa is an echogenic ring that represents the submucosa, followed by the hypoechoic muscularis propria and, most peripherally, the echogenic serosa.
👨💻In summary the five concentric layers are (from innermost to outermost):
1️⃣⚪️The innermost: it’s the echogenic mucosa interface.
2️⃣⚫️adjacent to the innermost: the hypoechoic mucosa.
3️⃣⚪️the next one is the echogenic submucosa( the thickest one)
4️⃣⚫️following the submucosa is the hypoechoic muscularis propria
5️⃣⚪️the outermost echogenic layer is the serosa (usually not depicted by ultrasound).
▶️WHY IS IT IMPORTANT❓❓
👨💻The gut signature can be used to differentiate benign conditions, where gut signature is preserved and long segments of bowel are involved, such as inflammatory bowel disease, from malignant conditions where there is destruction of gut signature usually short segments of bowel.
👨💻It can also be used to identify and recognize the appendix, enteric duplication cysts or differentiate bowel from intra-abdominal fluid collections.
👉FURTHER READING 📖:
▶️Muradali, Derek, and Deborah R. Goldberg. "US of gastrointestinal tract disease." Radiographics 35.1 (2015): 50-68. at São Paulo, Brazil