Keywords:
Diagnostic procedure, Plain radiographic studies, Small bowel, Obstruction / Occlusion
Authors:
H. Tie, P. Edwin; QLD/AU
DOI:
10.1594/ranzcr2016/R-0080
Methods and materials
A retrospective study of consecutive patients who underwent conventional abdominal radiography at the Gold Coast University Hospital over the span of 2 months – from 1st February to 31st March 2016,
was performed.
A total of 636 conventional abdominal radiographic examinations were performed in that period.
355 examinations did not include an erect abdominal radiograph and were excluded in this study – most commonly because: 118 examinations were performed to assess the radio-opacity of renal calculus,
37 for the position of medical devices like ureteric stents,
feeding tubes,
sacral nerve stimulator and intra uterine contraceptive devices,
14 were small bowel follow through series post oral contrast administration,
6 for the presence of foreign bodies and 13 examinations acquired supine and lateral decubitus images instead for suspected small bowel obstruction.
The remainder of the examinations with no erect images were performed for non-specific abdominal pain,
suspected bowel perforation or suspected bowel obstruction.
A further 25 examinations were excluded - where only erect images with no supine images were acquired - for suspected small bowel obstruction or suspected bowel perforation.
31 examinations performed on paediatric patients aged 18 years and below were also excluded.
Therefore,
225 examinations were included in this study and consisted of patients with age ranging from 22 to 93 who had both erect and supine images acquired during the same conventional abdominal radiographic examination.
The abdominal radiographic examinations were first reviewed on a PACS system for the presence of radiographic signs indicative of small bowel obstruction,
without knowledge of the final diagnoses.
The supine abdominal radiographic signs are demonstrated in Table 1 : 1) Dilated gas or fluid filled small bowel,
2) Dilated stomach,
3) “Stretch” sign,
4) Gasless abdomen and 5) “Pseudotumour” sign.
The erect abdominal radiographic signs are demonstrated in Table 2 : 1) Presence of >2 air fluid levels,
2) maximum width of air fluid level of greater than 2.5cm,
3) differential air fluid levels and 4) “String of beads” sign.
The final diagnoses were then obtained from CT abdomen/pelvis findings (dilated proximal small bowel >3cm and collapsed distal small bowel with/without a transition point,
presence of air fluid levels,
a compressed colon and the “beak sign” – abrupt tapering of the small bowel),
operation reports and electronic medical records of clinically diagnosed patients – the criteria being the need for a nasogastric tube and a positive response to nasogastric tube decompression/ conservative management.