Indian Journal of Radiology and Imaging Indian Journal of Radiology and Imaging

: 2005  |  Volume : 15  |  Issue : 1  |  Page : 109--115

Comparative study of plain abdomen and ultrasound in non-traumatic acute abdomen

K Gupta, RK Bhandari, R Chander 
 Department of Radio-diagnosis, Govt. Medical College, Amritsar, India

Correspondence Address:
K Gupta
Mahajan Villa, Vijay Nagar, Batala Road, Amritsar - 143001 (Pb)


The comparative study of plain x-ray film abdomen and ultrasound in non-traumatic acute abdomen was done in 50 patients with acute abdominal pain seen in the Department of Radiodiagnosis and Imaging of Govt. Medical College, Amritsar during the year 2000-2001. Ultrasound was highly accurate in diagnosing the exact cause of acute abdomen with high overall predictive accuracy of 98.3% and sensitivity of 90%. Plain x-ray abdomen was 100% diagnostic in GIT perforation, GIT obstruction, psoas abscess (caries spine) and renal colic with overall predictive accuracy of 4.1% and sensitivity of 60%.

How to cite this article:
Gupta K, Bhandari R K, Chander R. Comparative study of plain abdomen and ultrasound in non-traumatic acute abdomen.Indian J Radiol Imaging 2005;15:109-115

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Gupta K, Bhandari R K, Chander R. Comparative study of plain abdomen and ultrasound in non-traumatic acute abdomen. Indian J Radiol Imaging [serial online] 2005 [cited 2019 Jun 24 ];15:109-115
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Acute abdomen refers to presence of severe abdominal pain developing suddenly or over a period of several hours, and constitutes a significant percentage of emergency admissions. The term encompasses within it, a long list of differential diagnosis and poses one of the greatest challenges to a clinician.

Acute abdomen has been divided into four subdivisions [1].

1. Lower abdominal pain:

- Appendicitis

- Mesenteric adenitis

- Inflammatory bowel disease

- Pain of unknown etiology

- Gastroenteritis

- Diverticulitis

2. Upper abdominal pain:

- Cholecystitis

- Ulcer perforation

- Fitz Hugh Curtis syndrome

- Pancreatitis

3. Gynecological emergencies:

- Ectopic pregnancy

- Corpus luteum rupture

- Tubo ovarian abscess

- Pelvic inflammatory disease

- Endometriosis

- Pelvic adhesions

- Ovarian cyst

4. ICU patient pathology:

- Acalculous cholecystitis

- Perforation

- Mesenteric ischemia

An early and accurate preoperative diagnosis is needed for institution of prompt and appropriate management, in order to limit morbidity and mortality.


1. To evaluate the role of plain x-ray film abdomen in the diagnosis of acute abdomen.

2. To evaluate the role of ultrasonography in the diagnosis of acute abdomen.

3. To correlate the radiographic findings with sonographic features as to make the

provisional diagnosis.


A prospective study of 50 cases of non-traumatic acute abdomen was done in order to compare the plain x-ray film and ultrasound. Patients with trauma abdomen, pregnant women, and patients with compromised vital signs were excluded. A thorough clinical examination and biochemical investigations were carried out.

Every patient was subjected to plain X-ray film abdomen in supine, erect position, left lateral decubitus (wherever required) and upright chest radiograph (wherever required). Special investigations like intravenous urography, and contrast studies of gastrointestinal tract were conducted whenever necessary. All the patients were then subjected to ultrasound examination of abdomen.

Based on plain X-ray films and sonographic findings provisional diagnosis was made. The final diagnosis was made on the basis of operative findings/therapeutic response/histopathological/laboratory findings. Finally the accuracy of plain X-ray film abdomen and ultrasonography in evaluating patients with acute abdomen was determined.


[Table 1] shows that acute cholecystitis, acute appendicitis, acute pancreatitis, gynaecological pathologies and amoebic liver abscess were accurately diagnosed by ultrasonography, whereas radiographic accuracy was highest in renal cases.

As shown in [Table 2], it can be seen that ultrasound's predictive accuracy was 98.3% and sensitivity (90%), plain X-ray films predictive accuracy was 4.1% and sensitivity (60%) whereas clinical diagnosis, accuracy was 70.9% and sensitivity (83.3)%.

Based upon the observations made in 50 patients the following observations were obtained

case of hypertrophic pyloric stenosis and 1 (2%) case of psoas abscess with caries spine.

1. There were 24 males and 26 females in varying age groups in our series with a male to female ratio of 1:1.4

2. Age of the patients varied from 6 weeks to 70 years with a mean age of 37.6 years

3. The Most Common Chief complaint was acute pain abdomen in all the 50 cases (100%) and the least common complaint of amenorrhoea was only in one case (2%).

4. On clinical examination, 16 cases (32%) were diagnosed as that of acute cholecystitis. 6 (12%) cases of acute pancreatitis, 2 (4%) cases that of amoebic liver abscess, 3 (6%) cases of acute peptic ulcer, 13 (26%) cases as of acute appendicitis, 1 (2%) case of ectopic pregnancy, 6 (12%) cases of renal origin, 2 (4%) cases of intestinal obstruction and 1 (2%) case of hypertrophic pyloric stenosis.

5. On plain X ray film abdomen, 1 (2%) case was diagnosed as acute cholecystitis, 1 (2%) as appendicitis, 2 (4%) cases as G.I.T. perforation, 2 (4%) as G.I.T obstruction, 5 (10%) as renal lithiasis, 1 (2%) as caries spine with Psoas abscess. The plain X ray film abdomen made no contribution in the diagnosis of acute pancreatitis, hypertrophic pyloric stenosis, gynaecological pathologies, amoebic liver abscess. On ultrasound, 13 (26%) cases were diagnosed as acute cholecystitis, 9 (18%) as acute pancreatitis, 3 (6%) as amoebic liver abscess, 7 (14%) as acute appendicitis, 1 (2%) as ectopic pregnancy, 2 (4%) as torsion ovary/cyst, 5 (10%) as ureteric calculi, 1 (2%) as intestinal obstruction, 1 (2%) hypertrophic pyloric stenosis, 1 (2%) as G.I.T. perforation, 1 (2%) as pelvic collection, 1 (2%) as psoas abscess.

6. Based on final diagnosis made after histopathological/ therapeutic/operative examination done wherever necessary, we had 13 (26%) cases of acute cholecystitis, 9 (18%) cases of acute pancreatitis, 3 (6%) cases of amoebic liver abscess, 8 (16%) cases of acute appendicitis, 6 (12%) cases of gynaecological pathologies, 2 (4%) cases of torsion ovary/cyst, 1 (2%) case of ectopic pregnancy, 1 (2%) case of pelvic collection, 2 (4%) cases of tubo ovarian masses, 5 (10%) cases of renal origin, 2 (4%) cases of intestinal obstruction, 2 (4%) cases of GIT perforation, 1 (2%)

7. In 13 cases of acute cholecystitis, plain X ray abdomen was positive in 1 case only which showed multiple radiopaque shadows in right hypochondrium in the region of gall bladder. Sonographic

findings of cholecystitis were observed as thickened gall bladder wall (more than 3 mm) with wall oedema in all cases, Cholelithiasis in 12 cases, sonographic Murphy's sign in 7 cases, sludge in 3

cases, pericholecystic collection in 3 cases, CBD stone in 1 case. Thus diagnostic accuracy of 100% was found in gall bladderpathology on ultrasound.

8. Plain X ray film did not contribute to the diagnosis in any case of acute pancreatitis whereas on ultrasound 7 (77.7%) patients showed diffuse increase in the size of pancreas with diffuse hypoechoic echotexture. Focal hypoechoic area was seen in 2 (22.2%) patients. Complications of acute pancreatitis such as pseudopancreatic cysts, were seen in 2 (22.2%) patients. Gall stones were seen as associated findings in 2 (22.2%) patients.

9. Plain X ray film abdomen diagnosed only 1 (12.5%) out of 8 cases of acute appendicitis whereas ultrasound diagnosed 7 cases with predictive accuracy of 87.5%.

10. In 6 cases with gynaecological pathologies, plain X ray was not contributory in any of the case whereas ultrasound could correctly diagnose all the cases with the predictive accuracy and sensitivity of 100%.

11. Plain X ray abdomen was contributory in diagnosing all the 6 cases of ureteric colic and showed the radio opaque calculi. On ultrasound renal/ureteric calculi were seen in all the cases with demonstration of hydronephrotic pelvicalyceal system.

12. Out of 3 patients of amoebic liver abscess diagnosed only on ultrasound, 2 had single abscess and in 1 case had multiple abscesses. Plain X ray film did not contribute any finding in cases with liver abscess.

13. Plain X-ray abdomen correctly diagnosed 2 cases of intestinal obstruction and 2 cases of GIT perforation. Whereas Ultrasound correctly diagnosed, 1 case of intestinal obstruction, 1 case of GIT perforation and 1 case of infantile hypertrophic pyloric stenosis. Thus proving that plain X ray film abdomen's predictive accuracy and sensitivity was 100% in cases of GIT perforation and intestinal obstruction.

14. Plain X ray abdomen and ultrasound both were diagnostic in one case of psoas abscess with predictive accuracy and sensitivity of 100%.

Ultrasound was highly accurate in diagnosing the exact cause of acute abdomen with high overall predictive accuracy of 98.3% and sensitivity of 90%, whereas plain X ray abdomen was 100% diagnostic in GIT perforation, GIT obstruction, psoas abscess (caries spine) and renal colic with overall predictive accuracy 4.1% and sensitivity of 60%.

It can thus be concluded that Plain X ray film can be used as screening modality in the diagnosis of acute abdominal emergencies as it is universally available, more cheaper and was 100% diagnostic in GIT perforation, obstruction and renal lithiasis. Ultrasound examination is cheaper, non-invasive, quick, reliable and highly accurate modality in diagnosing the exact cause of pain and its origin in a patient presenting with an acute abdomen and thus helps the physician or surgeon to plan the timely management.


The comparative percentages in our study and study done2 on 50 cases of acute abdominal emergencies. SHOWING DISTRIBUTION OF CASES (AS PER FINAL DIAGNOSIS)

16 out of 50 cases were of hepatobiliary origin i.e. 32% and comprised the largest group. This was followed by conditions of gut which comprised 26% of our cases and acute pancreatitis in 18(2).

Accuracy of clinical diagnosis:

In our series the positive predictive clinical accuracy and sensitivity were variable and unpredictable,

the overall predictive accuracy of clinical diagnosis was 70.9% and sensivity was 83.3%, comparable with previous studies3. It was found that clinical diagnosis in cases of acute abdominal emergencies ranged from 40 69.9%. Ultrasonography plays an important role in evaluating patients of suspected acute cholecystitis with a reported accuracy of 95 99%(4). 13 cases of acute cholecystitis were correctly diagnosed on ultrasound when compared with final diagnosis and positive co-relation was obtained in 100% of cases.

The most sensitive criteria for diagnosis of acute cholecystitis on ultrasound is the presence of gall stones in association with focal gall bladder tenderness with positive predictive value of 92%[4]. Diffuse gall bladder wall was present in all cases of acute cholecystitis but it is a non specific finding as it can be found in many other conditions unrelated to gall bladder disease like ascites, hypoalbuminaemia, hepatitis, congestive heart failure, renal disease, adenomyomatosis, polyps, carcinoma etc[5]. A plain radiography shows an incidence of 10 15% radioopaque stones[6]. Thus, a negative plain radiography presents to be of little value in excluding gall stones. Only 15% of patients with cholelithiasis showed calcified stone on a simple abdominal radiograph(7). In our study, gall bladder stone was present in 1 (7.6%) out of 13 cases.

Ultrasound was successful in diagnosing all the 9 cases of acute pancreatitis and with associated pseudocyst seen in 3 cases [Figure 1]. Clinically serum amylase levels were raised in 7 patients only.

This is a proved fact that serum amylase value is not a specific pointer to diagnosis of acute

pancreatitis in patients with recurrent disease enzyme levels may be low because of progressive glandular destruction[8]. It was also observed that out of 102 patients 36 (52%) patients showed

diffuse enlargement of pancreas, focal enlargement occurred in the head 20 (28%) and in the tail in

14 (20%). Gall stones were associated in 26% of patients with acute pancreatitis[9] quite comparable

to our study, where gall stones were present in 2 (2l.2%) cases. The incidence of pseudocyst was 22.2% in our series. Similar incidence of pseudocyst was 11-18%[10].

In the present study, plain X-ray film was diagnostic only in 1 (12.50%) case out of 8 patients of appendicitis. The result was comparable to the earlier study where it was reported the appendicolith

by plain abdominal x-ray films in 7 to 14% patients of acute appendicitis[11].

Sonographic criteria for acute appendicitis include visualization of a non compressible appendix with maximum outer diameter >6 mm or visualization of an appendicolith within an appendix of any size, quite comparable with our study where in 5 out of 8 patients non compressible appendix was visualized with average outer diameter of 8.8 mm [Figure 2]. Appendicolith was visualized in 1 patient only. In 1 patient, localised well circumscribed fluid collection was found, suggestive of appendicular abscess.

In 1 out of 8 patients, ultrasound study was normal but acute appendicitis was diagnosed at surgery. Out of 90 patients with clinically suspected acute appendicitis, three patients were considered to represent false negative sonographic diagnosis[12]. In our study 1 patient out of 8 suspected cases of appendicitis which was considered to represent false negative sonographic diagnosis was proved to be acute appendicitis at operation. Thus, the predictive accuracy of ultrasound was 83.3% and sensitivity was 100%, comparable to the reported sensitivity in acute appendicitis 80 89%[13].

1 case of infantile hypertrophic pyloric stenosis was diagnosed by ultrasound and confirmed by surgery. Plain X ray abdomen did not help in diagnosing infantile hypertrophic pyloric stenosis. Sonographically, thickness of hypertrophied muscle from serorsa to mucosa is considered the most reliable measurement for the diagnosis of infantile hypertrophic pyloric stenosis. Muscle thickness of 4 mm or more, diameter of hypertrophied segment >15 mm and length of hypertrophied segment of pyloric >17 mm was considered diagnostic of hypertrophic pyloric stenosis. On transverse section, the pylorus

has an appearance of "Target or bull's eye"[14]. 2 cases of GIT obstruction, were diagnosed by Plain

X ray abdomen [Figure 3] as compared to 1 case by ultrasound and another case was diagnosed as

of peritonitis where free fluid with echoes was seen on ultrasound [Figure 3]. There were 2 cases of gastrointestinal perforation diagnosed on plain X ray film abdomen as compared to 1 case which was diagnosed on ultrasound where air was seen as an echogenic line beneath the diaphragm and another case showed free fluid with soft internal echoes. Thus, the predictive accuracy and sensitivity was

100% on plain X ray film abdomen. The extraluminal air of a perforated hollow viscus is visible in only

50 70% cases in plain X ray film abdomen[15]. On ultrasonography pneumoperitoneum appeared as

an echogenic line beneath the anterior wall of abdominal cavity, associated with characteristic

posterior shadowing or reverberation artefact. It is possible to detect as little as 1 to 2 ml of free

air[16]. Pneumoperitoneum can be demonstrated in nearly 90% of cases on plain radiography[17]. Abdominal radiographs sensitivity approaches 100% in cases of bowel obstruction and free peritoneal air[18].

In our study, there were 5 cases of acute abdomen with pathologies of renal origin. Though plain

X ray film showed radio opaque calculi in all the cases, yet ultrasound demonstrated the calculi with associated hydronephrotic changes in all the cases [Figure 4]. 1 case of ureteric calculi presented

with acute abdomen showed complete ureteric duplication with both the ureters inserting into the bladder [Figure 4]. Associated ureterocele was seen which was demonstrated on IVP as well as on ultrasound [Figure 4]. One of the ureter was obstructed by two radio opaque calculi as demonstrated

on plain film. The bifid collecting system is due to premature maturation of the ureter and are of no clinical significance. If ureteric insertion is obstructed with an associated ectopic ureterocoele, which

is a dilated intramural portion of the ureter which appears on excretory urography as a smooth filling defect arising from the lateral bladder wall giving the classic "cobra head" sign[19]. One case of pyonephrosis was diagnosed on ultrasound where dependent echoes and shifting debris were seen in collecting system [Figure 4]. The ultrasound is the modality of choice to detect dilated collecting system which contains dependent echoes and shifting debris[20].

In the present study we found that 1 case of psoas abscess presenting as acute abodmen showed destruction

of L4 and L5 vertebrae on plain X-ray, ultrasonographically, hypoechoic collection was seen in left renal area. Ultrasound was accurate in diagnosing all the 3 cases of liver abscesses. Follow up scans were done in all the cases. The abscesses reduced with treatment with antiamoebic drugs and or aspiration. Thus predictive accuracy and sensitivity of ultrasound was 100%. Comparable to accuracy rate percentage of 100%[24].


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