Intestinal Disorders: 11 Radiographs to Test Your Skills

Plain radiographs of the abdomen are a common first-line imaging study ordered for patients with abdominal pain. Nonradiologists need to be able to independently identify a variety of different intestinal pathologies. This radiograph demonstrates several dilated loops of small bowel with a stricture in the proximal transverse colon. At surgery, this patient was found to have a gangrenous loop of small bowel from a mesenteric artery embolism.

A patient presents with obvious signs of abdominal discomfort. What process is likely responsible for the large bowel obstruction in this abdominal radiograph?

The colonic distension is due to fecal impaction. The large bowel can be identified by the haustra and is distended from the ascending colon through the sigmoid. There is a definite paucity of air in the rectum caused by impacted feces leading to a buildup of fecal material and gas. This could be confirmed with anoscopy or manual examination.

A plain abdominal radiograph is shown in a patient with abdominal pain. What subtle sign is present that helps clinch the diagnosis?

The patient has air in Morison's pouch from pneumoperitoneum. On plain radiographs, a triangular (as in this case), semicircular, or crescent-shaped collection of air may be seen in the right upper quadrant bound by the 11th rib. On supine radiographs, collections of air in the right upper quadrant, which cannot be attributed to bowel gas, are usually the earliest sign for free intraperitoneal air.

An anterior-posterior sitting chest radiograph in the same patient is shown demonstrating free air under the right diaphragm (arrow), confirming the diagnosis of pneumoperitoneum.

A plain abdominal radiograph of a 6-year-old boy who presented with vomiting and acute pain in the right iliac fossa is shown. What 2 critical findings are present? (Hint: the infamous arrow provided by your friendly radiologist may narrow your focus.)

There are multiple loops of the dilated small bowel with small calcific nodules in the right iliac fossa. Small-bowel loops can be differentiated from large bowel because the valvulae conniventes in the small bowel will extend across the entire bowel wall, while the haustra in the large bowl will only extend part way. Calcified nodules in the right lower quadrant (arrow) are highly suggestive of appendicoliths. At laparotomy, an appendiceal mass was found that caused the small-bowel obstruction in this patient.

Flat (left) and upright (right) abdominal radiographs are shown in a patient with abdominal pain. What is causing this patient's discomfort?

The radiographs demonstrate a sigmoid volvulus that fills the entire abdomen. Two limbs of the sigmoid can be appreciated shaped like an upside down U with the limbs directed toward the pelvis (U shown). In the erect radiograph, air-fluid levels can be seen (arrows). The coffee bean sign is a classic finding in a sigmoid volvulus. The overlapped edematous walls form a dense white line surrounded by adjacent gas-filled bowel, which resembles a coffee bean. In these radiographs, the remainder of the large bowel is not dilated, presumably because the proximal point of the twist is not causing obstruction and thus allows drainage into the sigmoid.

A follow-up radiograph is shown after retrograde passage of a rectal tube demonstrating decompression of the sigmoid loop and normal bowel architecture.

An abdominal radiograph is ordered in a child. What ominous finding is present (let the arrow be your guide)?

The radiograph demonstrates pneumatosis intestinalis in a child with necrotizing enterocolitis. Pneumatosis intestinalis is air within the wall of the intestine often secondary to bowel ischemia. Linear or curvilinear lucencies are seen in the walls of the bowel (arrow). In a minority of cases, pneumatosis intestinalis may be nonemergent from chronic obstructive pulmonary disease, celiac disease, connective tissue disorders, steroid use, or chemotherapy.

Although in two thirds of cases plain radiographs are sufficient to diagnose pneumatosis intestinalis, computed tomography may more clearly demonstrate the process. On computed tomography, circumferential pneumatosis intestinalis is clearly visible (arrows).

What is the predominant abnormality in this patient with abdominal pain?

The radiograph demonstrates extensive haustral thickening (arrows) in a patient with pseudomembranous colitis. The haustra are the small pouched sacculations in the colon that give it a segmented appearance and help differentiate the colon from the small bowel on plain radiographs. In pseudomembranous colitis, the thickening is caused by bowel wall edema. The classic findings are colonic dilation, nodular haustral thickening, and thumb printing. In this radiograph the thickening is most pronounced in the transverse colon.

A barium enema further accentuates the haustral thickening.

A plain abdominal radiograph is shown from a 65-year-old man with acute abdominal pain and the passage of blood per rectum. In addition to the proximal small-bowel obstruction, the arrow is pointing to what other major abnormality?

The arrow is pointing to thumbprinting in a patient with ischemic colitis. Thumbprinting is a nonspecific finding of mucosal edema, which may be found with inflammatory bowel disease, pseudomembranous colitis, or ischemic bowel. As the edema worsens, the haustral markings may disappear completely, leaving a hoselike appearance to the colon. Narrowing and stricturing are other common findings.

This plain abdominal radiograph is from a 58-year-old man who underwent an upper gastrointestinal barium study for nonspecific dyspepsia 1 week previously. The patient initially presented with vague abdominal discomfort and the passage of blood per rectum. He now has increased abdominal pain and peritonism. What classic finding is the arrow pointing to and what is the diagnosis?

The arrow is pointing to the bas-relief sign in a patient with a perforated ischemic bowel. This is also known as the double-wall or Rigler sign. Normally only 1 side of the bowel wall can be seen. When both sides are seen, it indicates there is both intraluminal and extraluminal air. In a patient with worsening abdominal pain, bowel wall perforation is highly suspicious. During surgery, this patient was found to have a perforated ischemic bowel segment at the splenic flexure.

An abdominal radiograph from a 53-year-old woman who presents with clinical features of intestinal obstruction is shown. The image on the left is on initial presentation and the image on the right is 24 hours later. What is causing the patient's obstruction? Multiple findings are present, so do not get too distracted by the arrows.

The patient has a large cecal volvulus. The left image shows a large air-filled viscus without any visible haustra (short arrow). There are feces with air in the ascending colon (red arrow), indicating that there is not complete obstruction and some air is moving distally. The right image shows a shifting in the position of the viscus, demonstrating that it is mobile. The twist is outlined by the curved arrows. Classically, the caput cecum, or cecal head, is directed toward the right iliac fossa with the volvulus projecting up toward the upper left abdomen.

A plain abdominal radiograph of a 9-year-old patient with abdominal pain and vomiting is shown. The patient has a medical history of appendicitis complicated by peritonitis. What is the radiographic abnormality and what is the most likely cause?

The abdominal radiograph shows markedly distended loops of small bowel with effacement of the valvulae conniventes consistent with a diagnosis of small-bowel obstruction. In this patient with previous peritonitis, the obstruction was caused by abdominal adhesions. This child eventually recovered with conservative treatment.

A 67-year-old man presents with abdominal pain. What is the predominant abnormality in his plain abdominal radiograph?

The radiograph demonstrates a relative paucity of bowel gas. In an asymptomatic patient, this is often a normal variant. In a symptomatic patient, this can be found in a bowel obstruction when the loops of bowel are filled with fluid instead of air, as in this case. Other potential causes of a gasless abdomen are ascites, a large abdominal mass, post-colectomy, acute gastroenteritis, and bowel ischemia.