Acute Abdomen 急腹症 Radiology, Renji Hospital Shanghai Jiaotong University School of Medicine 钱黎俊
Learning objectives To understand the normal anatomy of the erect abdominal plain film To understand and able to identify the image findings of acute abdomen on plain film Be familiar with the role of CT in diagnosis of acute abdomen
Outline Acute abdomen Plain film and normal anatomy Gastrointestinal perforation 胃肠道穿孔 Intestinal obstruction 肠梗阻 Small bowel obstruction Large bowel obstruction Volvulus of sigmoid colon 乙状结肠扭转 Acute intussusception 肠套叠 Role of CT in diagnosis of acute abdomen
Acute abdomen Acute abdomen: a sudden, severe abdominal pain of unclear etiology that is less than 24 hours in duration Common causes including GI tract 消化道 Hepato-cholangio-pancreatic 肝胆胰 Urinary system 泌尿系 Gynecology 妇科 Aorta 主动脉
Plain film & normal anatomy The erect abdominal plain film Cover the bilateral diphragm To look for Soft tissue Gas pattern Fat shadow Bony structure R. diaphragm L. diaphragm Gastric bubble breast liver spleen L. Kidney R. Kidney sacroiliac joint Gas in small bowel
GI tract perforation 胃肠道穿孔
Gastrointestinal perforation diaphragm Free air diaphragm Free air Findings on erect plain film Gastric bubble Free gas beneath the diaphragm Sickle-, crescent-shaped translucency ( 镰刀状 新月状透亮影 ) not confused with gastric bubble Large quantity of free gas beneath bilateral hemi-diaphragm may merge together
Comparison of gastric bubble vs. free air Gastric bubble diaphragm thick layer in-between diaphragm gas beneath right diaphragm always indicates free air Free air diaphragm thin layer in-between Gas beneath right hemi-diaphragm always indicates free air Sickle-, crescent-shaped gas indicative of free air free air is very closed to the diaphragm
Large quantity of free gas beneath bilateral hemi-diaphragm may merge together
Gastrointestinal perforation: value of CT
Intestinal obstruction, Ileus (focus on small bowel obstruction) 肠梗阻 ( 主要讨论小肠梗阻 )
Small bowel obstruction Most common cause Adhesion (~75%) Findings on erected plain film distended bowel loops > 3 cm multiple air fluid levels on erect film Collapsed colon Air-fluid level = swallowed air + bowel fluid The 3,6,9 rule
Gas pattern Jejunum shows dense mucosal folds Ileum has fewer folds Both serosa of the jejunum and the ileum are smooth The colon has serosa indented by haustra, and mucosal folds do not cross the lumen colon valvulae conniventes 小肠环状襞 colon haustra 结肠袋
Jejunum Ileum Colon Jejunum shows dense mucosal folds whereas the ileum has fewer folds The colon has serosa indented by haustra, and mucosal folds do not cross the lumen
mechanical (simple, strangulated ) Paralytic 血运性 : thrombosis of PV system
肠梗阻影像学表现 麻痹性肠梗阻 腹部平片上表现为整个胃肠道普遍性扩张, 胃 小肠及结肠呈轻到中度扩大 胀气 肠道内气体多, 液体少
肠梗阻影像学表现 麻痹性肠梗阻 肠腔内液平面较低, 甚至肠道内几乎全为气体 胀气结肠和小肠靠紧, 类似蜂房状
paralytic ileus
paralytic ileus
Ileum Jejunum Identify the gas pattern: Jejunum shows dense mucosal folds whereas the ileum has fewer folds. Both serosa of the jejunum and the ileum are smooth
Distended bowel loop > 3cm Air-fluid levels String of pearls sign Jejunum obstruction: the distended bowel loops are generally located in the upper abdomen with the gas pattern of jejunum
Distended bowel loop > 3cm Air-fluid levels Ileum obstruction: the distended bowel loops are generally located in the lower abdomen with the gas pattern of ileum
Distended bowel loop > 3cm Air-fluid levels Jejunum obstruction: the distended bowel loops are generally located in the upper abdomen
Distended bowel loop > 3cm Air-fluid levels
Distended bowel loop > 3cm Air-fluid levels
Distended bowel loop > 3cm Air-fluid levels surgical clips
Distended bowel loop > 3cm Air-fluid levels String of pearls sign String of pearls sign: a row of small air bubbles in the abdomen on erect plain film. Indicative of a small amount of air trapped between the folds of the valvulae conniventes along the wall of predominantly fluid filled, dilated small bowel loops
Distended bowel loop > 3cm Air-fluid levels Jejunum shows dense mucosal folds whereas the ileum has fewer folds
jejunum ileum String of pearls sign
Small bowel obstruction: value of CT
Volvulus of sigmoid colon 乙状结肠扭转
Volvulus of sigmoid colon Volvulus: Obstruction of bowel loop by a twist around its mesenteric attachment Image findings Highly distended sigmoid colon (usually > 10cm) inverted-u shape white line (interposed colon walls) runs toward the pelvis coffee-bean sign Large air-fluid level on erect plain film
inverted-u shape white line to pelvis highly distended bowel loop
inverted-u shape highly distended bowel loop white line to pelvis Large air-fluid level Sigmoid volvulus: highly distended sigmoid bowel loop with inverted-u shape, white line of interposed colon walls toward the pelvis, the coffee-bean sign
Sigmoid volvulus: value of CT
Quiz M55yo after surgery with acute abdomen What s the diagnosis? A. Small bowel (jejunum) obstruction B. Small bowel (ileum) obstruction C. Small bowel obstruction complicated by perforation D. Sigmoid volvulus
Quiz M78yo with acute abdomen What s the most probable diagnosis? A. Small bowel obstruction B. Large bowel obstruction C. Sigmoid volvulus D. Paralytic ileus
Forget me not! Small bowel obstruction:
Thank you Dr. 钱黎俊 / email: dearqlj@hotmail.com