PLAIN FILM OF THE ABDOMENEdi Yanuarto Hidayat

INTRODUCTIONPlain films of the abdomen are used primarily to asses calcifications and intestinal obstruction or perforation.In case of acute abdomen, plain film of the abdomen should be made in 3 positions (Supine, upright or semi-upright, left lateral decubitus) + chest x-ray.

SUPINE

ERECT / UPRIGHT

LEFT LATERAL DECUBITUS

WHAT TO EXAMINEGas patternExtraluminal air / Free airSoft tissue massesCalcifications

NORMAL GAS PATTERNStomachAlmost alwaysSmall bowelTwo or three loops of non-distended bowelNormal diameter 3,0 cmLarge bowelIn rectum or sigmoid almost alwaysNormal diameter 5,0 cm

NORMAL GAS PATTERNGas in a fewLoops of Small bowelGas in stomachGas in rectum or sigmoid

NORMAL GAS PATTERNGasterColon DescendenFleksura hepaticaPsoas Line kiriFleksura lienalisHeparCaecumSacrumOs iliacaCaput Femoris

THE 3,6,9 RULEIt is a very useful guide to determine whether the bowel is dilated or not.

Maximum Normal DiameterSmall bowel 3 cmLarge bowel 5 6 cmCaecum9 cm

NORMAL FLUID LEVELSStomachAlwaysSmall bowelTwo or three levels possibleLarge bowelNone normally

NORMAL AIR-FLUID LEVELSAlways air-fluid levelin stomachA few Air-fluid levelin small bowelUpright Abdomen

LARGE VS SMALL BOWEL

CharacteristicLarge BowelSmall BowelPositionCircumferential the large bowel tends to frame the small bowelCentralContentsFaeces of variable consistencyFluid like and airMucosal / Wall PatternHaustral folds interspaced with plica semilunarisEncircling valvulae conniventes SizeUp to 5 - 6 cm, 9 cm for the caecumUp to 3 cm

LARGE VS SMALL BOWELValvulae ConniventesPlica semilunaris andHaustra

SMALL BOWEL

NORMAL GAS PATTERN IN THE NEWBORNGas in the stomach10 15 minutes after birth Gas in the proximal small bowel 30 60 minutes after birthGas in the distal small bowel 6 hours after birth Gas in the colon and rectum within 12 - 24 hours after birth

ABNORMAL GAS PATTERNS

ABNORMAL GAS PATTERNSParalytic Ileus (Adynamic)Mechanical obstructionSmall Bowel Obstruction (SBO)Large Bowel Obstruction (LBO)Localized Ileus

PARALYTIC ILEUSDefinition:Ileus that results from hypomotility of the gastrointestinal tract in the absence of mechanical bowel obstruction. Symptoms & Clinical findings:Abdominal distentionNausea and vomiting are variably presentThe bowel sounds absent or hypoactive

PARALYTIC ILEUSEtiology:Abdominal TraumaAbdominal Surgery (i.e Laparatomy)Serum electrolyte abnormalityHypokalemiaHyponatremiaHypomagnesemiaHypermagnesemia

PARALYTIC ILEUSEtiology:Inflammation Intrathoracic (Pneumonia, Myocardial Infarction)Intraabdominal (Appendicitis, Diverticulitis, Nephrolithiasis, Cholecystitis, Pancreatitis, Perforated duodenal ulcer)Intestinal ischemiaMedicationsNarcotics, phenothiazines, diltiazem or verapamil, clozapine, anticholinergic.

PARALYTIC ILEUSRadiologic findings:Gas in dilated small bowel and large bowel to rectumLong air-fluid levelsBowel wall thickening

PARALYTIC ILEUS

PARALYTIC ILEUSDifferential diagnosis:Mechanical obstruction (Ileus obstruction)Bowel pseudoobstruction / Ogilvie Syndrome

MECHANICAL OBSTRUCTIONDefinition:A mechanical obstruction of the bowel, preventing the normal transit of the products of digestion. It classifies into:Small Bowel Obstruction (if the obstruction occur in the level of small bowel).Large Bowel Obstroction (if the obstruction occur in the level of large bowel)

SMALL BOWEL OBSTRUCTIONSymptoms & Clinical Findings:Severe, colicky abdominal painBillious emesisMild abdominal distentionBowel sounds:Early: high pitched, hyperactive bowel soundsLater: hypoactive or absent bowel sounds

SMALL BOWEL OBSTRUCTIONEtiology:AdhesionsHerniaNeoplasmsSmall bowel volvulusIntussuceptionCongenital anomalies (in pediatric): small bowel atresia, small bowel stenosis, meconium ileus

SMALL BOWEL OBSTRUCTIONKey Concept:Bowel distention proximal to obstructionBowel collapsed distal to obstructionRadiologic findings:Dilated small bowel > 3,0 cm in diameterLittle gas in colonMultiple air fluid level (step ladder appearance) in upright / LLD positionString of pearls / String of beads appearanceCoiled spring appearance

SMALL BOWEL OBSTRUCTION

STRING OF PEARLS APPEARANCE - It can be seen in upright / LLD position It caused by small bubbles of air trapped in the valvulae conniventes

STEP LADDER APPEARANCEWhite arrow is a string of pearl appearance

COILED SPRING APPEARANCEIt only occurs in the dilated air-filled small bowel

LARGE BOWEL OBSTRUCTIONSymptoms & Clinical findings:Emesis may occur and is brown and fecculentSignificant abdominal distentionStool passage may be present in the early / partial obstruction.Obstipation in complete obstructionBowel sounds:Initial: high pitched, hyperactive bowel soundsLater: hypoactive or absent bowel sounds

LARGE BOWEL OBSTRUCTIONEtiology:Infectious / inflammatoryNeoplasticMechanical pathologyVolvulusIncarcerated herniaStrictureObstipationIn neonates: imperforate anus, meconium ileus, hirschprung disease.

LARGE BOWEL OBSTRUCTIONRadiologic findings:Dilated colon to point of obstructionLittle or no air in rectum / sigmoidMultiple air fluid level = step ladder appearanceHerring-bone appearanceLittle or no gas in small bowel if ileocecal valve remains competent.May look like SBO, large bowel decompresses into small bowel if ileocecal valve incompetent.

LARGE BOWEL OBSTRUCTION

HERRING BONE APPEARANCE

LOCALIZED ILEUSMay resemble early SBO

SENTINEL LOOP

SUMMARY FOR ABNORMAL GAS PATTERNS

Air in rectum or sigmoidAir in small bowelAir in large bowelParalytic IleusYesMultiple distended loopsYes distendedSBONoMultiple distended loopsNoLBONoNoneUnless ileocecal valve incompetentYes dilatedLocalized IleusYes2 3 distended loopsAir in rectum or sigmoid

WHAT TO EXAMINEGas patternExtraluminal airSoft tissue massesCalcifications

EXTRALUMINAL AIRSigns of pneumoperitoneum:Anterior subhepatic space airDoges Cap Sign (free air in Morissons pouch)Riglers sign on supine plain abdominal filmFalciform ligament signFootbal signThe cupola (Air accumulation beneath the central tendon of diaphragm)The triangle (Air trapped between three loops of bowel)

EXTRALUMINAL AIRSigns of pneumoperitoneum (cont.):Air under diaphragm on upright chest x-rayAir outlined against liver / flank on decubitus position

ETIOLOGYRupture of a hollow viscusPerforated ulcerPerforated diverticulitisPerforated carcinomaTrauma or instrumentationPost-op 5-7 days

ANTERIOR SUBHEPATIC SPACE AIR

DOGES CAP SIGNDoges cap sign refers to free air in Morissons pouch

DECUBITUS ABDOMEN SIGNPatient in LLDThere is evidence of free air between the abdominal wall and the liver (white arrow).There is also evidence of free fluid in the peritoneum (black arrow).

CRESCENT SIGN

RIGLERS SIGNThe sign refer to the appearance of the bowel wall on the plain film when it is outlined by intraluminal and extraluminal air.The extraluminal is the free peritoneal gas.

FOOTBALL SIGN

FOOTBALL SIGNMassive pneumoperitoneum andcould reasonably be said to displayfootball signThere is also falciform ligament sign, Riglers sign and air in the scrotum.

FALCIFORM LIGAMENT SIGNIf theres enough free air to outlinethe falciform ligament, there isusually enough air to also provide Riglers sign

CONTINUOUS DIAPHRAGM SIGNMassive pneumoperitoneum

CUPOLA AND LESSER SAC GAS SIGNWhite arrow: cupola signBlack arrow: lesser sac gas signThere is free connection between the lesser sac and the greater sac through the foramen of winslow.

WHAT TO EXAMINEGas patternExtraluminal airSoft tissue massesCalcifications

SOFT TISSUE MASSESHepatosplenomegalyTumor or cystBowel displacementPaucity of gas

SPLENOMEGALY

WHAT TO EXAMINEGas patternExtraluminal airSoft tissue massesCalcifications

CALCIFICATIONSEtiology:Gallstones or renal calculiLymph node calcifications

Staghorn calculi

Urolithiasis

REFERENCESwww.emedicine.comLarge bowel obstruction, 2004Colonic Obstruction, 2004Small bowel obstruction, 2004Bowel obstruction in the newborn, 2010Ileus differential diagnose, 2011Baker, R., Fischer, J., LBO, Mastery of Surgery, fourth edition, pp 1405-1407Haubrich, W., Schaffner, F., 1995, Gastroenterology, LBO, pp 1189www.learningradiology.comPlain film of the abdomenSign in RadiologyPaul C. Nevitt. The String of Pearl Sign. Radiology 2000;214:157-158

BOWEL PSEUDOOBSTRUCTIONSymptoms and clinical findings:Marked abdominal distention without pain or tenderness.Usually in elderly bedridden patient.Etiology: dismolity due to loss of the migrating motor complex and bacterial overgrowth.Radiologic findings:isolated, proximal large bowel dilatation.limited to colon only.

BOWEL PSEUDOOBSTRUCTION

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