Chin Med J (Taipei) 1998;61:S181.

Role of Plain Film Radiology in Acute Abdomen

Tiu Chui-Mei

Department of Radiology, Veterans General Hospital-Taipei, Republic of China

Abstract

A plain abdominal radiographic examination can be obtained for any patient suffered from acute abdomen easily and within a short period of time. Usually discomfort is minimal for this procedure. The abdomen has to be imaged from the symphysis to the diaphragm. The film should be able to delineate the detail of organ contours, soft tissue structures and bones.

A systematic analysis of the plain abdominal radiographs is very important. The most informative and diagnostic value of plain abdominal radiograph is its detection of free gas (pneumoperitoneum) in the abdomen. There are multiple signs indicating presence of pneumoperitoneum and prior knowledge of these signs and detail analysis of the abdominal film is essentail to obtain an accurate diagnosis.

The signs for pneumoperitoneum include: football sign, visible falciform ligament sign, Rigler's sign and inverted V sign. However free gas can also be found in the hepatorenal recess (Morison's pouch), para-and prehepaticarea.

Intraluminal gas is another clue for acute abdomen. The bowel gas pattern provides information for the bowel condition which includes the diameter of the intestinal loops, the presence of fixed loops. Evaluation of the thickness of the bowel wall is also essential to rule out ischemic bowel disease and /or inflammatory process.

The presence of gas inside solid organs (liver, pancreas, kidney and uterus) are usually pathognomic. Presence of gas inside intestinal walls are dangerous conditions for patients suffering acute abdomen.

The presence of gas in tubular structures, for example: bile ducts, renal pelvis, ureter, bladder, mesenteric and portal veins is also indicating presence of disease process.

The recognisation of the normal structures inside the abdomen is important. This includes the clear outline for psoas muscle, flank strip, liver.. spleen, kidneys and bladder. The normal fat planes for the pelvis is also important.

Pathologic calcifications and foreign bodies may also presented with signs of acute abdomen for example ureteral stone and gallstone. Soft tissue mass is easily recognized in plain abdominal radiographs.

With the advance of computed tomography (CT), plain abdominal radiographs help to tailored the examination to reduce radiation exposure, shortened examination time. However plain abdominal radiograph is still the most cost-effective diagnostic imaging in acute abdomen. (GAS and Mass, STONES and Bones)

[Chin Med J (Taipei) 1998;61:S181.]