Imaging differentiation of phytobezoar and small-bowel faeces: CT characteristics with quantitative analysis in patients with small- bowel obstruction.

OBJECTIVE

The objective is to use multidetector computed tomography (MDCT) to differentiate phytobezoar impaction and small-bowel faeces in patients with small-bowel obstruction (SBO).

METHODS

We retrospectively reviewed 91 consecutive SBO patients with surgically proven phytobezoars (n = 31) or adhesion with small-bowel faeces (n = 60). Two readers blinded to the diagnosis recorded the following MDCT features: degree of obstruction, transition point, mesenteric fatty stranding, intraperitoneal fluid, air-fluid level, pneumatosis intestinalis, and portal venous gas. MDCT measurements of the food debris length, attenuation, luminal diameter, and wall thickness of the obstructed bowel were also compared.

RESULTS

A higher grade of obstruction with an absence of mesenteric fatty stranding and intraperitoneal fluid was more commonly seen in the phytobezoar group than in the small-bowel faeces group (p < 0.01). The food debris length (phytobezoar, 5.7 ± 2.8 cm; small-bowel feces, 20.3 ± 7.9 cm, p < 0.01) and mean attenuation (phytobezoar, -59.6 ± 43.3 Hounsfield units (HU); small-bowel faeces, 8.5 ± 7.7 HU, p <0.01) were significantly different between the two groups. The ROC curve showed that food debris length <9.5 cm and mean attenuation value < -11.75 HU predicted phytobezoar impaction.

CONCLUSIONS

MDCT features with measurements of the food debris length and mean attenuation assist the differentiation of phytobezoar impaction and small-bowel faeces.

KEY POINTS

• MDCT examination helps to differentiate phytobezoar and small-bowel faeces. • A higher grade of obstruction is commonly associated with phytobezoar impaction. • Mesenteric fatty stranding and intraperitoneal fluid are frequently associated with small-bowel faeces. • Quantitative measurement of the obstructed bowel adds the diagnostic accuracy.