It is the radiological examination of abdomen and its Sometimes the patient is unfit to stand, then lateral contents. decubitus film is exposed. It is a relatively poor alternate

and does not provide enough information. The areas of It is used as a screening investigation in various lower chest and pelvis are also exposed to have complete abdominal problems such as; visualization of the abdomen.! Gastro-intestinal problems! Inflammations of abdominal viscera ! Abdominal trauma! Urinary tract problems! Gynaecological problems.! Vascular problems! Retroperitoneal problems.

The clinical data is always critically examined before performing the radiological investigations. It is inspected and interpreted in an organized and structured manner.

Whole of the exposed film is seen over an illuminater and never against sunlight or electric light to avoid wrong conclusions. Possible provisional diagnosis is made and The plain film is exposed with or without preparation. The objective interpretation is done.abdominal x-ray is exposed in appropriate position. The

x-ray pictures are exposed in erect or standing position Large amount of gas is seen in stomach and colon. and supine or lying position. Occasionally the films are Stomach is identified because of its anatomical position exposed in lateral position as well.and contents. An air-fluid level is seen under the left

OVER VIEW

PLAIN X-RAY ABDOMEN

INV - 08

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Muhammad Shuja Tahir, FRCS(Edin) FCPS (Hon)

PLAIN X-RAY ABDOMEN

Plain x-ray abdomen (normal film) after preparation

Plain x-ray abdomen (normal film) without preparation

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If a loop of bowel is seen filled with gas, it should not be hemidiaphragm normally. The presence of gas in the longer than 5-8 cm and should not be distended under bowel is seen on plain film. normal circumstances. The gas does not form a loop pattern in healthy persons.Gas is normally present in the stomach, small and large

intestine in small quantities. The gas is present as Gas shadows outside the intestine always indicate intra-individual bubbles of gas scattered in the bowel.abdominal pathology.

Multiple gas-fluid levels in the dilated loops of small or large gut indicate obstruction to the gastrointestinal flow. The level of obstruction is usually looked for.

The psoas shadows are visible as diverging lines on both sides of spine starting from first lumbar vertebra towards pelvis.

The psoas shadows may be obliterated by inflammatory, neoplastic and hemorrhagic (traumatic) lesions of the organ in front and in the vicinity (pancreas, spleen, liver etc.)

Ascites or presence of pus in the peritoneal cavity is identified by typical ground glass appearance. It offers valuable diagnostic information.

Peritoneal and extra-peritoneal contents of abdomen and pelvis are examined. Pancreas cannot be seen on Radio-opaque shadows and calcifications in the film are plain film of abdomen. seen and their anatomical correlation is interpreted.

Soft tissue shadows of liver, spleen, kidneys, and psoas muscle are visible normaly. Outline of urinary bladder, if filled with urine may be seen on plain film.

The plain x-ray film of the abdomen showing complete urinary system is called KUB film (Kidney, Ureter, Bladder film).

The injuries of abdomen show various radiological features depending upon the type, time and site of injury.

The common features seen on plain x-ray abdomen after various type of trauma are:

! Pneumoperitoneum! Ground glass appearance! Psoas shadow obliteration! Sentinel loops

ABDOMINAL TRAUMA

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SURGERY - INVESTIGATIONS

PLAIN X-RAY ABDOMEN

Plain x-ray abdomen showing diverging psoas shadows

Plain x-ray abdomen (normal) KUB film

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! Penetrating intraperitoneal injuriesTrauma may be;! Diagnostic fallopian tube insufflation

! Penetrating! Gas gangrene of intra peritoneal viscera.

! Blunt! Septic peritonitis with gas forming organisms

The penetrating injuries are usually visible on clinical examination. But the extent of injury may not be evaluated specifically on clinical examination. It presents This is a typical feature seen on x-ray abdomen. It is with pneumoperitoneum on radiological examination in visible due to presence of fluid, pus or blood in the the earlier part. peritoneal cavity. The presence of fluid gives this

appearance on plain x-ray abdomen. This is seen within Similarly blunt injuries of abdomen are diagnosed from few hours after penetrating injuries of abdomen when the clinical history and examination but extent of injury can peritonitis has already set in.only be assessed by various investigations and The blunt injury of abdomen may lead to injury to the sometimes even laparoscopy or laparotomy may be hollow viscera leading to leakage of gastro-intestinal required. contents into the peritoneal cavity and similar radiological

features.

Normally no air is present in peritoneal cavity. Pneumoperitoneum is the presence of free air in the peritoneal cavity. The most common site is usually under the right dome of diaphragm.

The penetrating injuries of abdomen present with free air in the peritoneal cavity. (Pneumoperitoneum)

The free air may be either due to perforation of the hollow viscus or the air entering from the exterior.

The free gas appears about 1-2 hours after the perforation of bowel.Absence of free gas in the peritoneal cavity does not necessarily exclude presence of perforation as it is absent in approximately 25 % cases of perforated duodenal ulcer. It is very rare in acute appendicitis even if it is perforated. It is seen in following conditions;! Perforated duodenal ulcer

The hematomas are formed which may obliterate the ! Perforated gastric ulcerpsoas shadow in case of injury to the solid organs. This ! Perforated gastric carcinomafeature is seen in hepatic, splenic and renal trauma. It is ! Perforated colonic carcinomaalso seen in pancreatic injuries or infections.! Perforated colonic diverticulum

! Traumatic gastric rupture! Traumatic small gut rupture! Traumatic colonic rupture An isolated distended loop of bowel is seen near the site ! Typhoid perforation of injured viscus or inflamed organ. This loop is called a ! Diagnostic pneumoperitoneum "sentinel loop". It is a feature due to body's efforts to ! Post laparotomy pneumoperitoneum localize traumatic or inflammatory lesions. The local ! Post laparoscopy pneumoperitoneum. distention of intestinal loop is due to local paralysis and

GROUND GLASS APPEARANCE

PNEUMOPERITONEUM

PSOAS SHADOW OBLITERATION

SENTINEL LOOPS

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SURGERY - INVESTIGATIONS

PLAIN X-RAY ABDOMEN

Plain x-ray abdomen showing ground glass appearance due to presence of fluid or pus in the peritoneal cavity

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These conditions can be diagnosed reasonably well by accumulation of gas in the intestinal loop.looking at the plain x-ray of the abdomen. It shows free gas under the diaphragm specially on right side in most In acute pancreatitis, the sentinel loop is usually seen in of the cases. Ileal perforation due to typhoid presents in left hypochondrium while in acute appendicitis, the this manner.sentinel loop is seen in right iliac fossa. The sentinel loop Perforations of other intra peritoneal hollow viscera also is seen in right hypochondrium in acute cholecystitis. present similarly. Perforation of appendix is rarely associated with pneumoperitoneum.Other radiological features of peritonitis are also seen in

late cases of blunt injuries of abdomen, when peritonitis has developed (Ground glass appearance and

The obstruction to the flow of contents of gastrointestinal pneumoperitoneum).tract can be;

! AcuteThere are many inflammatory lesions of peritoneal

! Subacuteviscera. The history of illness is present for some period.

! ChronicThe acute symptoms of intestinal perforation and resulting peritonitis are seen as pneumoperitoneum, ground glass appearance and Psoas shadow ! Adynamic ileusobliteration.

The causes of intestinal obstruction may be external or internal hernias, adhesions, neoplasia, volvulous, The duodenal ulcer and gastric ulcer perforations used to stenotic lesions, inflammatory lesions, meconeum and be one of the most common surgical emergencies during gallstones.previous decades. Now in our Indo-Pak subcontinent the

incidence of typhoid perforation is higher.After 3-5 hours of acute intestinal obstruction, enough gas and fluid accumulates to show distension of intestinal loops and gas fluid levels inside the intestine.The gas shadows are better seen in supine or lying position film. More than two fluid levels seen in small gut are abnormal and pathological.

The gas filled loops of gut show increase in their diameter due to distension.

The fluid levels are seen in erect or standing films or lateral decubitus films.

The small gut distended loops are recognized by the following features;

! The caecum is not distended in cases of small intestinal obstruction.

! The location of distended loops or air fluid level is central.

! Fine serrations along the margins formed by

INTESTINAL OBSTRUCTION

INFLAMMATORY & MISCELLANEOUS LESIONS OF MECHANICALABDOMEN

PARALYTIC

SMALL INTESTINAL OBSTRUCTION

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SURGERY - INVESTIGATIONS

PLAIN X-RAY ABDOMEN

Plain x-ray abdomen (supine film) showing dilated jejunal loops due to small gut obstruction

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than those normally seen in a single x-ray view.! The serrations are partial and incomplete. These

look like indentations into the transverse diameter of the colon. These are not opposite each other but are alternating.

In cases of volvulus of sigmoid colon, an inverted U shaped distended loop of colon is seen in the pelvis and abdomen. Double fluid levels may be seen.In cases of peritonitis, the signs of free fluid present in the peritoneal cavity, sentinel loop or a localized distended loop of bowel is seen adjacent to the lesion.

mucosal folds are complete along the transverse axis in case of jejunum.

! These fine serrations are very close to each other.! Featureless gut (with serrations) is seen in ileal

obstruction.! Step ladder pattern of air fluid shadows is also seen

some times.

The colon is distended from caecum to the obstructive lesion where the distension ends abruptly.

Haustrations are deeper and these are not continuous Most often these are not diagnosed from presence of soft along the transverse axis of colon. These are in fact tissue shadows. When these lesions are causing partial or alternating type.complete obstruction or perforation, these can be

If caecum gets distended more than 9-10 cm it is likely to detected indirectly from;perforate.Colonic obstruction presents with following features on x- ! Radiological features of intestinal obstructionray abdomen; ! Features of intestinal perforation

! Features of generalized peritonitis! The caecum and colon are distended! The distended colonic loops are present at the

periphery in the abdomen. It shows the features of peritonitis and may be detected ! The gas fluid levels are seen and these are more by plain x-ray abdomen.

VOLVULUS OF COLON

COLONIC CARCINOMA

COLONIC OBSTRUCTION

ACUTE MESENTERIC OCCLUSION

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SURGERY - INVESTIGATIONS

PLAIN X-RAY ABDOMEN

Plain x-ray abdomen (erect film) showing multiple air fluid levels in the loops of jejunum due to small gut obstruction.

Plain x-ray abdomen showing marked dilatation of the large gut from caecum to splenic flexure due to large gut obstruction.

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INTRA ABDOMINAL ABSCESSES

GYNAECOLOGICAL PROBLEMS (FIBROID UTERUS)

OVARIAN TUMOURS

GALL STONE ILEUS

These can not be seen on plain x-ray film directly. Various features such as presence of sentinel loops, abnormal diaphragmatic shadows and ground glass

! Colo-biliary fistula due to gall stone erosion.! Duodeno-biliary fistula due to gall stone erosion or

duodenal ulcer penetration.! Sphinterotomy or sphinteroplasty of sphinter of

oddi ! Choledocho-duodenal anastomosis! Acute cholecystitis with gas forming organisms.

In women, uterine shadow may also be seen specially if the patient is not fat or the fibroid is calcified. It is easily seen on plain film x-ray of the pelvic area.

appearance may help in suspecting the lesion.

Presence of air fluid level under the diaphragm is highly Normally these are not picked up on plain film at an early suspicious of subphrenic collection. Ultrasound stage. Teratomas may be detected because of examination helps to confirm the diagnosis. radiopaque structures present in these tumours

(cartilage, teeth etc)

In cases of gall stone ileus when the gall stone has ulcerated into the duodenum and descended along the small intestine, it causes small gut obstruction. It presents with following features;

! All the features of small intestinal obstruction are present.

! It is diagnosed by presence of stone which is usually radio-opaque.

! Gas shadow is seen in the biliary tree (common bile duct, common hepatic duct and hepatic ducts).

! The gall bladder may also be filled by the gas.

Gas shadow is seen in biliary tree in following conditions;

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SURGERY - INVESTIGATIONS

PLAIN X-RAY ABDOMEN

Dilatation of large gut due to twisted caecum and ascending colon due to volvulus of caecum (Plain x-ray abdomen)

Air fluid level under the right dome of diaphragm due to presence of gas in the right subphrenic abscess (Plain x-ray abdomen)

Gas in the biliary passages and gall bladder due to gall stone ileus (Plain x-ray abdomen)

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RENAL TUMOURS

CYSTS

CALCULUS DISEASE

FOREIGN BODIES

REFERENCES

Soft tissue renal shadow is usually seen in properly prepared patients and occasionally renal lesion may be detected on plain x-ray abdomen.

Soft tissue shadows of larger cysts may occasionally be out lined on plain film. But most often these are unde-tected and require ultrasound examination or urography for proper detection.

Stones in the gall bladder and stones in the urinary system are seen as radio-opaque shadows in the relevant area.

These cases are diagnosed if the stones are radio-opaque otherwise ultrasonography, cholecystography or urography is required.

Foreign bodies may be ingested accidently. These usually pass through the gastro intestinal tract easily if small and not pointed. Even needles may pass without causing perforation. 1. Peter Armstrong. Martin L. Wastie. Plain Abdomen: In

Diagnostic Imaging. 4th Edition Blackwell Scientific publications London. pp 133-143, 1998The plain x-ray of abdomen helps in finding the site and

type of foreign body if it is radio-opaque. If the foreign body is obstructed at some place, it may be removed surgically.

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SURGERY - INVESTIGATIONS

PLAIN X-RAY ABDOMEN

Plain x-ray abdomen (normal film) after preparation

Multiple radio-opeque shadows in the upper part (multiple biliary and bilateral renal stones) (Plain x-ray abdomen)

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