Peritoneum Flashcards
USF of abdominal wall hernia
Abdominal wall lump increasing in size with increased intra-abdominal pressure
• USidentifies nature of herniated contents (bowel/omentum) & site of muscle/facial defect
• Omental fat: Echogenic/hypoechoic tissue without peristalsis on ultrasound
• Intestinal loops on ultrasound: “Target”echo pattern with strong central echoes representing air in lumen ± peristalsis
Obstructed hernia: Tubular fluid-filled structure with valvulae conniventes (small bowel) or fecal material (colon) & dilated fluid-filled intra-peritoneal bowel loops ± free fluid on ultrasound
• Color Doppler: Strangulated hernia; absence of vascularity within bowel wall & mesentery
• Identify anatomical layers, localize focal abdominal wall defect, compare with opposite side & identify contents
• If bowel herniation, check for complications (irreducibIe/0bstruction/ strangula tion)
Checklist for abdominal wall hernia
Consider CHECKLIST hernia; urgent • Abdominal wall hernia, if posterior margin of any abdominal wall mass cannot be seen on US
• Secondary tumor: Scar metastasis, metastasis (melanoma, Sister Mary Joseph nodule) Abdominal Wall Abscess/Collection
• Post-operative abdominal wall abscess
• Suture/scar granuloma
• Subcutaneous collections or cysts
Image Interpretation Pearls
• Check for abdominal wall defect, hernial sac contents, peristaltic movement & vascularity (if bowel)
USF of groin hernias
Indirect IH: Passes through internal inguinal ring, down the inguinal canal & emerges at external ring
• Direct IH: Occurs in floor of inguinal canal, through Hesselbach triangle
• US:Identifies the nature of herniated contents; bowel (enterocele) or omentum (omentocele) or both
• Omental fat: Echogenic tissue without peristalsis
• US:Intestinal loops; “target” echo pattern with strong central echoes representing air or fluid in lumen ± peristalsis • Nonobstructed hernia; active peristalsis ± movement of intestinal contents
• UScan reveal reducible/irreducible nature of hernia
• Increase in hernia size during cough or Valsalva maneuver
Valsalva maneuver may help differentiate type of hernia
• Direct hernia: Distended pampiniform plexus is displaced by hernia sac
• Indirect hernia: Impaired swelling of pampiniform plexus seen
Diagnostic checklist for groin hernias
Hernias that protrude from lateral inguinal fossa are indirect IH
• Hernias that protrude from medial & supra vesical fossae are direct IH
USF of acsites
usaccurate at quantifying & localizing ascites
• US:Uncomplicated ascites; homogeneous, freely mobile, anechoic; deep acoustic enhancement
• Free fluid: Acute angles where fluid borders organs
• Free fluid shifts with change in patient position
• Complicated ascites: With coarse or fine internal echoes on US
• Loculated ascites: Adhesions, chronic ascites, malignancy, infection, immobile
• Sonolucent band; small amounts of fluid (5-10 mL) in Morrison pouch, around liver
• Triangular fluid cap; distended bladder displaces fluid to peritoneal reflection adjacent to uterine fundus
• Small free fluid in cul-de-sac; physiologic in women
Transvaginal US: Excellent for detection of even minimal fluid (0.8 mL) in pelvis
• Thickening of gallbladder wall; more than 3 mm in benign ascites; in carcinomatosis less than 3 mm thick
• Cerebrospinal fluid ascites: Small amounts of free fluid normal with ventriculoperitoneal shunt
• Pancreatic ascites: Peripancreatic, lesser sac, anterior pararenal space
• Bedside US to screen for ascites in critically ill or post-operative patients ± drainage
USF of peritoneal carcinomatosis
Omental cake, soft tissue implants on peritoneal surface
• Omental deposits: Hypoechoic omental masses, nodular echogenic mass seen against anechoic ascites
• Thickening of mesenteric leaves due to desmoplastic reaction; typically mesenteric side of terminal ileum
• Peritoneal implants: Nodular masses along the parietal & visceral peritoneum or hypoechoic rind-like thickening of peritoneum
Transvaginal US: Lobulated mass in pouch of Douglas
• Psammomatous calcification in peritoneal implants seen in ovarian serous cystadenoma (up to 40% with stage III/IV disease)
• Ascites: Complex ascites with septation, hyperechoic nodular debris
In absence of ascites it may be difficult to detect peritoneal implants < 3 mm in size
• ±Enlarged hypoechoic retro-peritoneal & mesenteric lymph nodes
• Bilateral cystic adnexal masses due to peritoneal metastasis from GI malignancies; “Krukenberg” tumor
• Color Doppler: May detect vascularity in omental/peritoneal deposits
• US excellent for initial screening, followed by CT/MR for further evaluation
Checklist for peritoneal carcinomatosis
TB peritonitis
o Causes symmetric thickening of peritoneum, ileo-cecal thickening, ascites, hypoechoic mesenteric lymph nodes & calcification
• Omental cake
• Peritoneal and mesenteric implants
• Ascites
USF of peritoneal space abscess
Best diagnostic clue: Fluid collection with mass effect ± gas bubbles or air-fluid level
• Complex fluid collection with internal low level echoes, membranes or septations
Dependent echoes representing debris; seen as fluid-fluid level
• Bright linear echoes with reverberation artifacts representing gas bubbles; diagnostic of infection
• Inflamed fat adjacent to abscess: Echogenic mass
• Peritonitis (infective): Diffuse inflammation of parietal or visceral peritoneum
• Tuberculous peritonitis: Matted bowel loops with heterogeneous inter-bowel exudate
• Color Doppler: Hypervascular periphery, avascular center of abscess & hyperemic (inflamed) adjacent fat
Checklist for peritoneal space abscess
Loculated collections with internal debris or septations with appropriate clinical features
