Abdominal X-Ray Interpretation Using PPPE + ABCDO

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Step 1: PPPE – Technical Adequacy

• Projection/Position: Single frontal AP supine abdominal radiograph (the patient was likely unable to stand for an erect film). The image covers the whole abdomen.

• Patient Details: The film is correctly labeled for our 80-year-old male patient; date and markers (e.g., an “L” for left side) are present (note the “L” marker on the image).

• Positioning: The patient is supine (“liegend” noted on film). There is minimal rotation.

• Exposure: Adequate. The bowel gas and outline of the distended colon are clearly visible. Some of the lung bases are included. Overall image quality is sufficient for diagnosis.
   

Step 2: A – Air (Gas Pattern)

• Abnormal gas pattern: There is a massively dilated loop of colon occupying much of the abdomen. It extends from the pelvis and loops upward, with the two ends of the loop forming a shape reminiscent of a giant “coffee bean” or inverted “U”. The apex of this distended loop reaches the right upper quadrant of the abdomen. The center of the “coffee bean” has a faint line or cleft which represents the twisted sigmoid walls pressed together.

• Absent gas where expected: Notably, there is no gas in the rectum or distal sigmoid on this film – the colon beyond the twist is decompressed. Additionally, aside from this volvulated sigmoid, the rest of the colon is relatively empty or collapsed (a small amount of gas is seen in the ascending colon, but none distally). No significant small bowel dilation is seen, suggesting the ileocecal valve might be competent (preventing small bowel reflux).

• No free air: There is no free intraperitoneal air under the diaphragms on this supine film (free air would be easier seen on an erect chest X-ray, but none is apparent here), so no perforation at this time.
   

Step 3: B – Bowel (Location, Size, Wall)

• Location & morphology: The distended colon loop arises from the pelvis (i.e. sigmoid colon origin) and spans across the abdomen. The walls of this loop are smooth and lack normal haustral markings (the stretching and twisting can efface haustra). This forms the classic “bent inner tube” or coffee-bean appearance of a sigmoid volvulus. In sigmoid volvulus, the two limbs of the distended sigmoid form the arms of the coffee bean; they taper down to a twist point in the left lower quadrant. Indeed, on this film the inferior aspect of the loop tapers toward the left pelvis, where the torsion (point of obstruction) is located.

• Bowel size: The sigmoid colon is enormously dilated (often can reach >10 cm diameter). This patient’s loop measures roughly that magnitude. The cecum and ascending colon do not appear grossly distended (they are in normal anatomic position), supporting that this is an isolated sigmoid twist rather than a generalized obstruction.

• Bowel wall: No obvious pneumatosis (air in the colonic wall) is seen. The colonic wall is thin due to distension; if ischemia were present, one might see thickening or air in the wall, which is not evident here on plain film.
   

Step 4: C – Calcifications and Bones

• Calcifications: No abnormal calcifications are noted in the abdomen. In particular, no urinary stones or biliary stones are visible to confuse the picture.

• Bones: The spine shows degenerative changes but no acute fracture. Both hip joints and pelvic bones are intact on X-ray. Incidentally, vascular calcifications (e.g., aorta) are not prominent.
   

Step 5: D – Devices and Foreign Bodies

• Devices: There are no surgical clips or medical devices visible. (Sometimes a rectal tube might be seen if one had been placed for decompression, but not in this initial film.)

• Foreign bodies: None seen. The opaque oval object over the left pelvis in some sigmoid volvulus cases is the sigmoid mesenteric fat (“balloon” sign), but in this image the densities are all bowel.
   

Step 6: O – Other Findings (Organs & “Oh no!”)

• Organs/soft tissue: Liver, spleen, and kidneys do not show any obvious abnormalities on this film (though evaluation is limited). No obvious mass is present aside from the colonic distension. Psoas shadows are not well seen, likely due to overlapping distended bowel and maybe patient’s body habitus.

• “Oh no!” findings: The major red flag here is the extreme colonic dilation in which risk of perforation is high if not relieved. No free air (perforation) is seen at this time, which is fortunate. There are also no signs of distal obstruction like a tumor on this plain film (the obstruction is functional due to twisting). We must treat this as an acute emergency to prevent the dreaded “oh no” scenario of perforation.
   

Summary of Findings and Diagnosis

The X-ray shows a grossly distended loop of large bowel, arising from the pelvis, with a characteristic “coffee bean” shape, and absence of gas in the rectum. These findings are classic for a Sigmoid Volvulus, which is a torsion of the sigmoid colon causing a closed-loop large-bowel obstruction. The diagnosis is acute sigmoid volvulus causing large bowel obstruction. This explains the patient’s subacute course of distension and obstipation. It is a surgical emergency due to risk of bowel ischemia and perforation.

 

Diagnosis: Acute sigmoid volvulus
 

Key Teaching Points:
 

• Coffee Bean Sign: Sigmoid volvulus classically presents on AXR as a hugely dilated sigmoid colon loop that often points from the left lower quadrant toward the right upper quadrant, forming a coffee bean or inverted U shape. The inner walls of the twisted loop may appose to create a line (“cleft”) through the center of the gas shadow. Another sign is the Frimann-Dahl sign, which is the convergence of three dense lines toward the site of the torsion (these are the margins of the twisted colon and mesentery).  Recognizing these signs on a plain film can allow prompt diagnosis.
   

• Differentiating Sigmoid vs. Cecal Volvulus: Both are large bowel volvuli. In cecal volvulus, the distended loop is usually in the mid-abdomen or left upper quadrant, often with a coffee-bean shape pointing toward the left (since the torsion is in the right lower quadrant). The cecum may be extremely enlarged and sometimes you see small bowel obstruction if the ileocecal valve is incompetent. In sigmoid volvulus (more common), the loop arises from the pelvis and points to the right upper quadrant and often the small bowel is not distended (competent ileocecal valve). The history can also differ (cecal volvulus often in slightly younger patients).
   

• Clinical Context: Sigmoid volvulus typically occurs in older adults, often with a history of chronic constipation or a high-fiber diet that leads to an elongated, mobile sigmoid colon. It can also be seen in neuropsychiatric patients or those in nursing homes. 
   

• Pitfalls: Do not mistake a massively distended stomach or pseud-obstruction for a volvulus. Also, ensure to check for perforation, if the volvulus has already perforated, management is surgical, and endoscopy is contraindicated. The presence of Rigler’s sign or free subdiaphragmatic air would indicate perforation (which was not seen in this case).

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