Can low-dose abdominal CT replace abdominal plain film in evaluation of acute abdominal pain?

Figures & data

Table I.  The number of included patients examined with the different modalities during January, February, and March in the years 2000, 2002, and 2004.

Method	2000	2002	2004	Total
Abdominal plain film	82	2	2	86
Standard-dose computed tomography	0	45	15	60
Low-dose computed tomography	0	0	76	76

Table II.  Effective dose in millisievert (mSv) for different radiograms reported to Swedish Radiation Protection Authority.

Radiograms	Effective dose (mSv)
Abdominal plain film	1.3
Standard dose CT abdomen	7.3
Low dose CT abdomen	4.2
Chest X-ray	0.1
Urography	1.3
Lumbar spine X-ray	1.6
Neck X-ray	0.4
Shoulder X-ray	0.01
CT abdomen unenhanced and enhanced	10.5
CT thorax	2.8
CT skull	2.3
CT urography	7.7
Colon enema, double-contrast	8.2

Table III.  Radiologic and final diagnoses of the patients examined with abdominal plain film (APF).

Diagnosis group	Radiologic diagnosis	Final diagnosis	Patients, n
A: Diagnostic report	Ileus, volvulus	Ileus, volvulus	8
	Free gas	Perforation	3
	Obstipation	Obstipation	5
	Ascites	Ascites	1
B: Report valuable but not diagnostic	Slight bowel dilation	Obstipation	1
	Gastric retention	Gastritis, gastric hernia	1
	Pancreas calcifications	Pancreatitis	1
	Kidney stone (ureteral stone not described)	Ureteral stone	1
	Ascites	Ascites and malignancy	1
	Dilated bowel, with or without metastases	Colon or rectal cancer	3
	Known pathology, status quo	Known pathology, status quo	1
C: Report not diagnostic	No conclusive finding	Perforation	1
	No conclusive finding	Appendicitis	3
	No conclusive finding	Diverticulitis, colitis	9
	No conclusive finding	Obstipation	4
	No conclusive finding	Gastric ulcer	1
	No conclusive finding	Gastroenteritis	2
	No conclusive finding	Bowel gangrene	2
	No conclusive finding	Cholecystitis	6
	No conclusive finding	Pancreatitis	4
	No conclusive finding	Liver cirrhosis	2
	No conclusive finding	Urinary infection	1
	No conclusive finding	Urine retention	1
	No conclusive finding	Malignancy	5
	No conclusive finding	Cardiac disease	1
	Obstipation	Gall-stone	1
	Obstipation	Pneumonia	1
D: Clinically unclear diagnosis	No findings	Unspecific abdominal pain	12
	Obstipation	Unspecific abdominal pain	4
Total			86

Table IV.  Radiologic and final diagnoses of the patients examined with standard-dose computed tomography (SDCT).

Diagnosis group	Radiologic diagnosis	Final diagnosis	Patients, n
A: Diagnostic report	Ileus, volvulus	Ileus, volvulus	4
	Free gas	Perforation	4
	Obstipation	Obstipation	2
	Ascites	Ascites	2
	Diverticulitis, colitis	Diverticulitis, colitis	2
	Hernia	Hernia	1
	Invagination	Invagination	1
	Gall-stone, cholecystitis	Gall-stone, cholecystitis	2
	Ureteral stone, hydronephrosis	Ureteral stone, hydronephrosis	3
	Previously unknown malignancy	Previously unknown malignancy	1
	AAA (abdominal aortic aneurysm)	AAA, acute operation	1
B: Report valuable but not diagnostic	Slight bowel dilation	Ileus	1
	Gastric retention	Gastritis, gastric hernia	2
	Gastroenteritis?	Gastroenteritis	1
	Ascites	Bowel gangrene	1
	Gall-stone	Cholecystitis	1
	Ascites	Ascites and malignancy	2
	Dilated bowel, with or without metastases	Colon or rectal cancer	1
	Known pathology, status quo	Known pathology, status quo	2
C: Report not diagnostic	No conclusive finding	Ileus	1
	No conclusive finding	Diverticulitis, colitis	1
	No conclusive finding	Obstipation	1
	No conclusive finding	Gastric ulcer	1
	No conclusive finding	Gastroenteritis	1
	No conclusive finding	Cholecystitis	1
	No conclusive finding	Urinary infection	2
	Obstipation	Gall-stone	1
	Ascites	Obstipation	1
D: Clinically unclear diagnosis	No findings	Unspecific abdominal pain	12
	Obstipation	Unspecific abdominal pain	4
Total			60

Table V.  Radiologic and final diagnoses of the patients examined with low-dose computed tomography (LDCT).

Diagnosis group	Radiologic diagnosis	Final diagnosis	Patients, n
A: Diagnostic report	Ileus, volvulus	Ileus, volvulus	7
	Free gas	Perforation	3
	Obstipation	Obstipation	7
	Ascites	Ascites	1
	Diverticulitis, colitis	Diverticulitis, colitis	7
	Appendicitis	Appendicitis	2
	Pancreatitis	Pancreatitis	3
	Gall-stone, cholecystitis	Gall-stone, cholecystitis	3
	Ureteral stone, hydronephrosis	Ureteral stone, hydronephrosis	5
	Previously unknown malignancy	Previously unknown malignancy	2
	AAA (abdominal aortic aneurysm)	AAA, acute operation	1
	Abscess	Abscess	1
	Haematoma	Haematoma	2
	Hernia	Hernia	1
B: Report valuable but not diagnostic	Slight bowel dilation	Ileus	2
	Slight bowel dilation	Obstipation	1
	Pancreatitis	Cholecystitis	1
	Ascites	Ascites and malignancy	2
	Dilated bowel, with or without metastases	Colon or rectal cancer	1
	Mesenteric artery calcification	Ischaemic bowel disease	1
	Known pathology, status quo	Known pathology, status quo	5
C: Report not diagnostic	No conclusive finding	Ileus	1
	No conclusive finding	Obstipation	2
	No conclusive finding	Cholecystitis	1
	No conclusive finding	Cardiac disease	1
	Gastric retention	Multiorganic failure	1
D: Clinically unclear diagnosis	No findings	Unspecific abdominal pain	10
	Obstipation	Unspecific abdominal pain	2
Total			76

Table VI.  The percentage of patients distributed between the groups A, B, C, D for the radiological methods abdominal plain film (APF), standard-dose computed tomography (SDCT), low-dose computed tomography (LDCT), and computed tomography (CT) total. Number of patients in parenthesis.

	A: Diagnostic report	B: Report valuable but not diagnostic	C: Report not diagnostic	D: Clinically unclear diagnosis	Total number of patients
APF	20% (17)	10% (9)	51% (44)	19% (16)	86
CT Total	50% (68)	18% (24)	12% (16)	21% (28)	136
SDCT	38% (23)	18% (11)	17% (10)	27% (16)	60
LDCT	59% (45)	17% (13)	8% (6)	16% (12)	76

Table VII.  Average number of additional abdominal radiograms and non-abdominal radiograms (in parentheses) for the radiological methods APF, SDCT, LDCT, and CT total.

	Within 1 week	During admission	Within 30 days
APF	0.94 (0.42)	1.00 (0.50)	1.23 (0.82)
CT Total	0.33 (0.20)	0.38 (0.30)	0.61 (0.44)
SDCT	0.32 (0.28)	0.38 (0.47)	0.65 (0.63)
LDCT	0.34 (0.13)	0.37 (0.17)	0.58 (0.29)

Table VIII.  The percentage of additional abdominal radiograms during admission for the radiological methods APF, SDCT, LDCT, and CT total. Number of patients in parenthesis.

Number of additional abdominal radiograms	0	1	2 or more	Total number of patients
APF	38% (33)	36% (31)	26% (22)	86
CT Total	69% (94)	26% (36)	4% (6)	136
SDCT	72% (43)	23% (14)	5% (3)	60
LDCT	67% (51)	29% (22)	4% (3)	76

Table IX.  Average calculated dose in millisievert (mSv) with original radiograms excluded and included (in parenthesis).

	Abdominal radiograms within 1 week	Abdominal radiograms during admission	Abdominal radiograms within 30 days	Total radiograms within 30 days
APF	3.6 (4.9)	4.0 (5.4)	5.0 (6.3)	5.3 (6.7)
SDCT	4.2 (8.5)	1.7 (9.0)	2.3 (9.5)	2.8 (10.1)
LDCT	1.2 (5.4)	1.3 (5.5)	1.9 (6.1)	2.0 (6.2)