小腸阻塞的X光的影像特色(X ray film in small bowel obstruction)

腹部X光影像是次於理學檢查方便的評估工具。有些特徵需要注意。

時機

X 光片能出現大約在小腸阻塞3到5小時後出現，12小時候開始明顯。

有主要兩點要看：

其一，脹小腸

X光片呈現 dilated small-bowel loops measuring>3cm in diameter 伴隨 air/fluid levels.(站立的X片)
但是Air/fluid levels 可能出現在機械性小腸阻塞和無動性腸阻塞( adynamic ileus.)，此外有另外兩項X光特徵：

• Progression of dilation results in a “stepladder” pattern of air/fluid levels
• “string of beads” or “string of pearls” sign： the bowel is predominantly fluid-distended with minimal amounts of air trapped in the valvulae這個在機械性腸阻塞有診斷價值，可用來區別adynamic ileus
• Closed-loop obstruction refers to segmental dilation of bowel due to obstruction at two points. Occasionally a dilated loop is seen to acquire a “coffee bean” shape. Persistence of this dilated loop on serial x-rays should raise suspicion for a closed-loop obstruction.

其二，有無大腸氣

dilated small-bowel loops with air/fluid levels with minimal to moderate colonic gas，這代表可能是腸阻塞(尚未完全塞住)也有可能只是non-obstructive ileus。

但dilated small-bowel loops with 沒有大腸氣，這就真的腸阻塞了，也是阻塞近端有氣，但遠端都沒有氣。

參考資料

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