Gratitude is expressed to Dr. Price E. Thomas, determine some of factors controlling rate of action of curare. J. Physiol. 106:20P, 1947. Department of Physiology, Kirksville College of 10. Kalow, W.: Hydrolysis of local anesthetics by human serum Osteopathy and Surgery, for his guidance in the cholinesterase. J. Pharmacol. Exper. Therap. 104:122-134, Feb. 1952. writing of this paper, and to Mrs. Kathryn Balder- 11. Beecher, H. K., and Murphy, A. J.: Acidosis during thoracic son for preparation of the diagrams. surgery. J. Thoracic Surg. 19:50-70, Jan. 1950. 12. Lehmann, H., and Silk, E.: Succinylrnonocholine. Brit. M. J. 1:767-768, April 4, 1953. 13. Frumin, J. M.: Hepatic inactivation of succinylcholine in dog. Fed. Proc. 17:368, 1958. 1. Boba, A., et al.: Effects of apnea, endotracheal suction, and 14. Barnes, J. M., and Davies, D. R.: Blood cholinesterase levels oxygen insufflation, alone and in combination, upon arterial oxygen in workers exposed to organo-phosphorous insecticides. Brit. M. J. saturation in anesthetized patients. J. Lab. Clin. Med. 53:680-685, 2:816-819, Oct. 6, 1951. May 1959. 15. Lehmann, H., and Ryan, E.: Familial incidence of low pseudo- 2. Bard, P.: Medical physiology. Ed. 10. C. V. Mosby Co., St. cholinesterase level. Lancet 2:124, July 21, 1956. Louis, 1956. 16. Lehmann, H., and Simmons, P. H.: Sensitivity to suxame- 3. Ruch, T. C., and Fulton, J. F.: Medical physiology and bio- thonium; apnoea in two brothers. Lancet 2:981-982, Nov. 8, 1958. physics. Ed. 18. W. B. Saunders Co., Philadelphia, 1960. 17. Tod, H., and Jones, M. S.: Study of cholinesterase activity in 4. Whitehead, R. W., and Draper, W. B.: Respiratory reflex origi- nervous and mental disorders. Quart. J. Med. 6:1-3, Jan. 1937. nating from thoracic wall of dog. Anesthesiology 8:159-165, March 18. Brennan, H. J.: Dual action of suxamethonium chloride. Brit. 1947. J. Anaesth. 28:159-168, April 1956. 5. Stechishin, 0., Voloshin, P. C., and Allard, C. A.: Neuromuscu- 19. Churchill-Davidson, H. C., and Richardson, A. T.: Decame- lar paralysis and respiratory arrest caused by intrapleural neomycin. thonium iodide (C10); some observations on its action using electro- Canad. M. A. J. 81:32-33, July 1, 1959. myography. Proc. Roy. Soc. Med. 45:179-186, April 1952. 6. Li, T. H., et al.: Early respiratory depression by curare and 20. Greene, N. M.: Fatal cardiovascular and respiratory failure curare-potassium antagonism. J. Pharmacol. Exper. Therap. 104:149- associated with tracheotomy. New England J. Med. 261:846-848, 161, Feb. 1952. Oct. 22, 1959. 7. Dripps, R. D.: Abnormal respiratory responses to various 21. Dripps, R. D., and Severinghaus, J. W.: General anesthesia "curare" drugs during surgical anesthesia; incidence, etiology and and respiration. Physiol. Rev. 35:741-777, Oct. 1955. treatment. Ann. Surg. 137:145-155, Feb. 1953. 22. Dripps, R. D.: Immediate decrease in blood pressure seen at 8. Marsh, D. F.: Distribution, metabolism, and excretion of conclusion of cyclopropane anesthesia; "cyclopropane shock." Anes- d-tubocurarine chloride and related compounds in man and other thesiology 8:15-35, Jan. 1947. animals. J. Pharmacol. Exper. Therap. 105:299-316, July 1952. 23. Downs, T. M.: Carotid sinus as etiological factor in sudden 9. Holmes, P. E. B., Jenden, D. J., and Taylor, D. B.: Attempt to anesthetic death. Ann. Surg. 99:974-984, June 1934.

The survey film in acute abdominal disorders

CARL L. NEUFELD, D.O.,° Merchantville, N.J. Acute intra-abdominal conditions may be baffling not only to the surgeon but to the internist as well. Unfortunately, the surgeon is too frequently inter- In perusing the literature on this subject, one is ested in one of three things: Is there free air impressed with the relative paucity of material beneath the diaphragm? Is there ( an often sought available. The major fundamental contributors to but infrequently seen finding) a stepladder pat- the interpretation of the "flat" or "scout" abdominal tern? Is there evidence of biliary or urinary calculi? film have been Laurell and Frimann-Dahl. With Clinical and physical signs are sometimes poorly the exception of an occasional article written by defined or absent, thus making it difficult to decide Wangensteen, Bigler, Sussman, and Levitin, few whether or not to operate. original investigations can be found. That the ab- In substantiating or establishing a diagnosis, con- dominal film has not received the notice it has siderable aid might be obtained from survey or deserved might be the fault of the radiologist, who "scout" films of the abdomen. It should be re- has not convinced the surgeon of its importance membered that the roentgen examination of the in diagnosing acute abdominal conditions. abdomen is not in competition with the clinical examination, but in cooperation with it. Both are This paper, submitted in partial fulfillment of the requirements for certification of the American Osteopathic Board of Radiology, was performed with the intention of effecting the most prepared during the residency of Dr. Neufeld in the Department of accurate diagnosis possible through the combined Radiology of Doctors Hospital, Columbus, Ohio, of which Dr. Theo- dore C. Hobbs is chairman. efforts of the internist, the surgeon, and the radi-

°Address, 212 Cherry Hill Apts., W. ologist.

JOURNAL A.O.A., VOL. 60, JUNE 1961 827 Technical factors instances only an indefinite suspicion of anatomic variation can be determined. Ordinarily, the rela- A survey film is one obtained without employing tive size and shape, changes in density, or other contrast media and without any preparation of the significant alterations can be determined for the patient. The minimum preliminary examination liver, spleen, pancreas, kidneys, psoas muscles, and should include an anteroposterior recumbent pro- urinary bladder. Occasionally, similar changes can jection of the abdomen (including the diaphragm be noted in the prostate, seminal vesicles, and the and the symphysis pubis), an anteroposterior erect uterus and its adnexa. Also seen are multiple retro- film of the same area, and an erect posteroanterior peritoneal structural variations. chest film. The kidneys are checked for size, position, and Diseases of the chest are frequently manifested contour. The course of the ureter is followed for by referred pain in the abdomen. Right basal pneu- possible identification of urinary calculi. Often the monia, for instance, could present symptoms of clue to a pathologic process is obtained by study- acute gallbladder disorders or acute . ing the bony architecture of the vertebral bodies Also, abdominal lesions can produce secondary or the pelvis. However, study and attention should changes in the thoracic cavity, such as basal atelec- be critically directed towards each of the factors tasis, as a result of diminished diaphragmatic ex- considered below. cursions. If care is taken to direct the x-ray beam in a The flank area • Understanding the roentgen pic- direction horizontal to the dome of the diaphragm, ture of the flanks is the key to diagnosis of many even small amounts of air can be detected. acute abdominal lesions. These findings are valu- The value of the erect position in x-ray diagnosis able in the demonstration of abnormal signs in of acute abdominal conditions is well established. cases of exudates and inflammation. However, the left lateral decubitus position, utiliz- Four distinct, stripe-formed zones are found in ing grid cassettes, can replace erect positioning in the flank, and denser spaces are seen between them. debilitated patients; this is of comparable accuracy The broadest and longest of these zones is a medial in demonstrating free air in the peritoneal cavity stripe corresponding to the extraperitoneal fat layer and air-fluid levels in the intestine.' Because more or properitoneal fat layer, which separates the coils of small bowel are located on the left side, parietal peritoneum from the transverse abdominal the right lateral recumbent film is better for deter- muscle. This separating stripe is significant since it mining fluid levels. However, left lateral recumbent is obliterated very early in an inflammatory process. films are better to determine the presence of pneu- The next two lateral lucent stripes are the fat lay- moperitoneum. ers between the internal and external abdominal According to the experience of Frimann-Dah1,2 muscles. the best results are obtained when relatively low The fourth fatty layer, most laterally situated, milliamperage and high kilovoltage are used; this corresponds to the subcutaneous fat. In this layer will yield better film latitude, which is of particular a fine network, composed of fibrous tissue and small importance in the flank area. vessels, is seen. When there is a pathologic condi- tion this network may be more pronounced. In Examination of the abdominal film older people the stripe is indistinctly marked be- cause the fat is only slightly developed and because In the plain film certain organs can be accurately of the relatively high water content of fat in persons delineated, and others only seen in part; in some of that age. An increased abdominal content, such as that seen in adipose patients and in infants (as a result 11111.111111111111/111111111111111111 lllll 11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 of normally gas-filled intestinal coils) will con- tribute to a lateral bulging of the flanks over the In substantiating or establishing striped area. However, in nonobese adults, a similar process is present only when there is a pathologic a diagnosis, considerable aid might be condition, such as edema of the abdominal wall or free fluid.2 obtained from survey or "scout" films of the Distribution of the gas pattern • The normal film of the abdomen may show gas in the stomach, the abdomen. It should be remembered that the duodenal bulb ( pars superior ), the terminal ileum, or the colon. roentgen examination of the abdomen Gas in the small bowel is abnormal except in infants. In small children it varies in amount and is not in competition with the clinical produces differing degrees of distention; it origi- nates when they swallow air while crying, gasping, examination, but in cooperation with it or eating. The relatively slack abdominal wall con- tributes somewhat to the reduced absorption of

011111111,1111111111111t111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 gases. In addition, a small child's ileocecal valve

828 is nearly always incompetent, so that there is some free fluid is present and that does not exist. regurgitation of gas from the colon into the terminal The demonstration of the magenblase (stomach ileum. bubble) in the erect position permits some concept In adults, some gas is often accumulated in the of soft-tissue space between the top of the stomach terminal ileum, most commonly after an enema. and left hemidiaphragm. If this distance exceeds This accounts for the occasional fluid level seen 5 mm., a filling defect within the fundus is sug- in that area. gested.4 The gas bubble may be absent or con- Gas in the bowel, in general, is from three stricted in size, as in an infiltrating carcinoma of sources: 68 per cent is swallowed air; 22 per cent the stomach. Downward, lateral, or anteroposterior is caused by diffusion from the blood stream; and displacement of the gas bubble is found when there 10 per cent is the result of digestive fermentation. is enlargement of the left lobe of the liver, splenic The swallowed air seen in the stomach is broken rupture, tumor masses, subphrenic abscess, or the into small bubbles in the jejunum and carried in accumulation of peritoneal fluid. Occasionally, an solution with the intestinal contents. Interference elongated stomach fluid level suggests small bowel with the normal passage of intestinal contents will obstruction. Stomach distention appears in advanced affect the gas held in solution. It will be thrown pyloric obstructions ( or in obstruction from other out of solution, and it will then appear on the causes); as a terminal condition, particularly in x-ray film.3 uremia; or in acute reflex gastric dilatation. There are two abnormal situations where small Small, spotted areas of small bowel gas are of bowel gas will be found. One is in paresis of the no significance, especially in patients having pain. bowel, in which there is no peristalsis; this is a However, if a small localization of gas remains paralytic or adynamic ileus. The other condition constant in a given area on several repeated ex- is a mechanical block in the lumen, called a me- aminations, one must begin to suspect a mechanical chanical or dynamic ileus. obstruction, , devitalized bowel, or an A dynamic ileus represents reflex inhibition, either abscess. This sign has also been referred to as the " by stimulation of the sympathetic fibers or by "sentinel loop. inhibition of the parasympathetic fibers. Intestinal If the patient has not recently had an enema, absorption takes place within the numerous villi gas in the rectum implies that if obstruction is lining the surface of the small bowel. The con- present, it is not complete. Displacement of the tinuous change in shape of the villi during intestinal rectal shadow from the center of the pelvis sug- peristalsis provides new surfaces for absorption. gests a space-occupying lesion. Overdistended gas- With cessation of peristalsis, no new surfaces are containing bowel in the periphery of the abdomen exposed. The gas present is no longer held in is characteristic of large bowel obstruction, except solution, and it becomes evident on the film. for a distention localized in the upper right quad- Paralytic ileus is responsible for the distention rant, which is characteristic of sigmoidal volvulus. which follows 75 per cent of abdominal operations; It is important to note the amount of separation it disappears on the third or fourth postoperative between bowel loops; this indicates peritonitis or day. When the ileus disappears, the patient com- a localized abscess formation. If the distance ex- plains of "gas pains," which probably are due to ceeds 3 mm., peritonitis is probably present.4 the resumption of peristaltic activity. Diminished gas shadows may be seen in infants, Adynamic ileus may also follow emotional dis- as the bowel may not contain gas for the first 24 turbances such as fear, fright, or pain. It accom- to 36 hours; they may also be seen in a patient panies instrumentation, follows spinal cord injuries, with clinical evidence of obstruction who is having and results from severe extremity fractures. This considerable vomiting. An unexplainable absence is not a serious condition, and fatal sequelae do not follow; but its differentiation from the more serious mechanical obstruction of the small bowel, which :111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 lllllll 1111111111111111111111111111111111111111111111111 does require immediate therapy, is important. It is generally contended that gases containing nitro- The minimum preliminary examination gen ( such as air) are slowly absorbed from the intestine, while those containing greater ratios of should include an anteroposterior oxygen or carbon dioxide vanish rapidly. The main portion of the gas is absorbed by the blood vessels recumbent projection of the abdomen and expelled by respiration. One might speculate whether or not the reason aged persons normally (including the diaphragm and the symphysis have more intestinal gas is because they have poor absorption as a result of atherosclerosis, and a pubis), an anteroposterior erect relatively higher blood nitrogen concentration. The shape of a meteoristic or distended colonic film of the same area, and an loop in the flank is also noteworthy. The lateral border is flattened and the haustrae are sharply erect anteroposterior chest film edged, while the medial border is still normal with

rounded contours. Such a finding proves that no 111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111M1111111111111111111111111111111

JOURNAL A.O.A., VOL. 60, JUNE 1961 824 of gas where it is usually found may be pathogno- of increased activity of the glands in the obstructed monic of a space-occupying lesion. bowel. The bowel shortens, giving less absorptive Extraluminal gas beneath the diaphragm is usual- surface. This tends to increase intraluminal pres- ly pathognomonic of a ruptured hollow viscus, ex- sure. cept when seen soon after operation. Extraluminal The venous channels in the lower ileum are gas may also be observed in abscess pockets or in mostly submucosal. With an increase in intra- the biliary tract, as well as in a retroperitoneal luminal pressure these latter veins are easily col- location, where it appears in a streaky pattern. lapsed. The heart continues to force blood into the Spontaneous usually indicates arteries, but the veins cannot return the flow. Fi- perforation of a gastrointestinal viscus, if the patient nally, blood seeps into the lumen of the bowel, has not had an abdominal operation in the past 2 adding to the pressure and fluid. Pressure necrosis, or 3 weeks. Free intraperitoneal air may not always gangrene, and perforation of the bowel will follow, be demonstrable in spontaneous peritoneum. Among resulting in peritonitis.9 the causal factors are: the liver adheres to the right diaphragm; fluid in viscus prevents gaseous Free fluid in the peritoneal cavity • The demon- escape; perforation might have sealed itself off stration of free fluid in the pelvis usually requires before more than 5 cc. escape; or roentgenographic an erect, lateral decubitus, or transabdominal pro- technic may be faulty, such as failure to make the jection. Since the slow accumulation of gas in the examination with the patient in an erect position intestine makes its loops lighter than fluid-filled or failure to allow the patient to lie on his left ones, these lighter loops have a tendency to ascend. side or to stand upright long enough.5 The condition is different when the intestines are In differential diagnosis it is important to elimi- filled with fluid. Then they tend, as does free fluid, nate interposition of colonic gas between the liver to occupy the lowest parts of the abdomen and are and the diaphragm. The presence of haustral mark- found with the fluid in the lesser pelvis or in the ings differentiates these two conditions. flanks. The diagnosis of free fluid, exudate, or blood is Fluid in the intestine • The fluid normally present exhibited on the films as a density which nearly in the intestine originates from ingested food and corresponds to that of the musculature or the from the secretions of the intestine. Fluid levels parenchymatous organs. Small amounts of fluid in in the small bowel are typical of obstruction. 8 In the pelvis are demonstrated between the perito- high obstruction, vomiting is early and fluid levels neum and the intestinal loops as a narrow density. are few; in low obstruction, the fluid levels are Small quantities of fluid are also visible as irregular increased in number and situated lower. Fluid lev- stripes between gas-filled intestinal coils. The bowel els in the large bowel may be due to a recent segments are separated by the fluid which appears enema, and these are considered normal. as broadened white stripes of a triangular or stellate Mechanical obstruction, complete or incomplete, shape. If such a picture is found, about 20 to 30 cc. results in changes on the x-ray film. Causes for of fluid are present. If the density of the triangular these changes may include: neoplasm, cicatrizing stripes is broader, the assumption is that 100 to 150 enteritis ( which kinks or compresses the bowel ), cc. of fluid are present; there is often a "new-moon" volvulus, intussusception, unreduced internal or shape between the symphysis and the intestine. The external hernia, localized abscess, impacted gall- fluid in the pelvis, as in the flanks, gives the intes- stone at the ileocecal valve, and edema of the tinal loop a rounded form, contrary to the "normal" bowel caused by low plasma-protein concentration.7 edged, angulated, or polyhedric appearance. If the The "axiom" that the appearance of fluid levels exudate forms a half-moon shaped density, approxi- in the erect scout film is pathognomonic of intes- mately 200 to 300 cc. of fluid are estimated to be tinal obstruction has recently been challenged. 5 It present. When the entire pelvis is filled with fluid, is claimed that fluid-level production is the anti- giving a full-moon appearance, the amount of fluid thesis of a saline cathartic action. Nausea encour- usually present is more than % liter? ages air swallowing; so any circumstance which Difficulty arises in differentiating this density mobilizes fluid in the intestine and causes nausea from pathologic changes in the pelvis, such as will give rise to fluid levels. Here, the most likely ovarian tumors or abscesses. The criterion for dif- condition would be a variant which causes bowel ferentiation is that tumors have a cranial convexity stasis. Whether irritants or cathartics have been ( often easily demonstrated against the intestine), ingested should be determined before abdominal whereas the exudate has no distinct upper contour, flat films are made. the density continuing towards the flanks. One An almost complete, low small bowel obstruction method of differentiation is to place the patient on can exist for days with minimal or no symptoms. his side (preferably left) and project the x-ray The fact that a patient had a bowel movement does beam horizontally ( anteroposteriorly) through him. not exclude obstruction. The bowel distal to the If the mass or corresponding density persists in that obstruction will continue to evacuate its contents. position, a tumor is probably present. If a definite As soon as gas distends the bowel, there is inter- reduction is apparent, an exudate is suggested. ference with absorption, causing more gas and fluid Fluid in that position may float towards the flank, to accumulate. Fluid also accumulates as a result whereas the tumor remains in the same position.

830 Emptying the bladder before taking the x-ray film will rule out one possible source of confusion. Collection of fluid in the flanks may be associated with fluid in the pelvis, or it may be isolated—for instance, in localized peritonitis or as a result of hemorrhage. To demonstrate the presence of fluid it is best to place the patient on his side for a short interval to permit fluid accumulation in the lower flank. When fluid is present in the lateral part of the abdomen, a greater-than-normal density ap- pears. The shadow is similar to that of musculature and the parenchymatous organs. Because the fluid pushes the intestinal coils medially, the margin of the flank stripe or properitoneal fat line is smooth and sharp; the image, therefore, is unchanged. Small amounts of fluid, most distinctly exhibited in hemorrhages, appear as a fine stripe-formed den- sity lateral to the intestine, and this density extends from the flanks downward to the iliac fossa. A density of this kind is often no broader than the intestinal wall, but it is distinguished from the wall by the straight margin of the fluid, which is viewed as a continuous band. Fluid, therefore, outlines the abdominal cavity laterally, and the density has a straight and smooth contour, shown in a position lower than normal in the pelvis.1° Fig. 2. Uterine leiomyomata. Ascites • In most cases the roentgen appearance of ascites (Fig. 1) shows a diffuse density, perhaps rowed; it may even vanish completely. The pro- covering the entire abdominal field, thus allowing peritoneal fat line is often blurred because of only a dim visualization of the normal contours of edema and hyperemia, as a result of local or gen- the organs and of the musculature. The border of eralized peritonitis. The small bowel tends to float; the flank is pushed more and more laterally so that the diaphragm rises, especially on the left; and the extraperitoneal fat becomes continually nar- altered diaphragmatic excursion with marked ele- vation sometimes produces a pressure atelectasis at the base of the lungs.

Abdominal masses • Localized intraperitoneal abscesses may be demonstrable (Fig. 2) as homog- enous soft tissue shadows, most commonly in the appendiceal or pelvic regions. If they contain gas, films taken with the patient in an upright position will usually reveal the wall of the mass, as well as fluid levels. 11 Occasionally, abscesses present a mottled pattern of many tiny gas bubbles. Occa- sionally renal or ovarian tumors are seen; if these masses contain calcification, they probably have persisted for a long while. Dermoid cysts are seen as relatively transparent, round or oval images of irregular density with a dark ring at the periphery, representing the cyst wall. Sometimes, parietal cal- cifications and plaques of bony tissue with dente- lated outlines appear among the cysts. Ovarian cysts are seen as oval or round shadows of uniform darkness, often with signs of parietal calcifications.

Opaque shadows • The two opacities of greatest surgical significance in the abdominal scout film are gallstone shadows, which are usually located in the right upper quadrant and which occasionally have a laminated appearance, and ureteral calculi. The lucent center in a phlebolith distinguishes it from a calculus.

831 and hypogastric vessels, calcifications in the adrenal gland, calcified mesenteric lymph nodes which ap- pear as calcified "mulberries," calcified uterine fi- bromata, and calcifications in the pancreas. Of a series of pancreatic calcifications found by x-ray, it was determined that when the amount of calcium increased, the frequency and degree of pain often decreased.13 In the individual case, however, the degree of pain had no relation to the amount of calcification. But the degree of pancreatic dysfunc- tion was correlative with the degree of calcification. Round or plaquelike areas of calcification are some- times seen in the pancreatic area; these may result from healed acute hemorrhagic pancreatitis. Calci- fications in the liver parenchyma are observed in cavernous hemangiomas, phleboliths, and in vari- ous cysts, such as echinococcus cysts and tuber- culous granulomas.

The psoas shadows • Being most pronounced in athletes and pyknic individuals, the psoas shadows are normally slightly convex laterally; conversely, the borders are somewhat concave in asthenic per- sons. The psoas shadows are significant in that they give important clues to the presence of any retro- peritoneal abnormalities, such as tumor masses or Fig. 3. Modified stepladder pattern caused by intestinal obstruc- abscesses. Indirect signs of an infection extending tion from adhesions. Note calcification of the splenic vasculature. into the retroperitoneal tissue may result in ob- scuration and obliteration of the psoas muscle border. Increased muscle shadow density is also Ureteral calculi passing along the urinary tract seen in severe cases. Spinal curvature toward the are most often detained at one of the three points unaffected side is likewise resultant. In perine- of natural constriction: at the ureteropelvic junc- phritic abscess, oddly enough, the kidney outline is tion, as the ureter crosses the bony pelvis, and at maintained. If the infection is not diffuse, but re- the ureterovesical junction. A careful search should mains localized, the psoas shadow may not be en- be made in these locations, although it is possible tirely obliterated. Similarly, carcinomatous infiltra- for a stone to lodge at any location. As they pass tions may obliterate the psoas muscle if the process down the ureter, small, irregular stones formed in is extensive. the calyces of the kidney pelvis present typical symptoms of renal colic. Such stones may remain Roentgen findings in specific in situ, gradually being enlarged to enormous pro- abdominal disorders portions by successive urinary deposits. They some- times form complete kidney pelvis casts, known as Perforated peptic ulcers and sigmoid diverticula "stag-horn calculi."12 • The diagnosis of a perforated ulcer is based Urinary calculi may be confused with numerous mainly on the demonstration of pneumoperitoneum. pathologic changes in the abdomen; among these Demonstration of free fluid in the peritoneal cavity are gallstones, calcifications of costal cartilages, or signs of a peritoneal irritation are also findings calcified mesenteric lymph nodes, fecaliths, phlebo- for this diagnosis. However, it is important to re- liths, calcified necrotic fat nodules in the omentum, member that the absence of free gas does not foreign bodies in the intestinal tract, and warts and exclude or even militate against the diagnosis of a moles on the skin. Artifacts, due to marks on the perforation. Occasionally, the small gas bubbles film or the intensifying screen, may cast confusing which escape from a hollow viscus are absorbed shadows. spontaneously and rather quickly, thereby explain- Other opacities sporadically found in the abdomi- ing negative findings. It is also possible that the nal and periabdominal regions are colonic diverti- perforation may heal spontaneously. The air is best cula (retaining barium), iodized oil along nerve visualized under the diaphragm and above the sheaths, buckshot in the , bis- dense liver parenchyma, but it can also be entirely muth in gluteus muscles, splenic tubercles or splenic confined to the left side, as in perforations into the arterial calcifications in the aged ( Fig. 3), vas- omental bursa. cular metallic clips used in neurosurgical proce- The intestinal condition in perforation also de- dures, wire suture in the abdominal wall, bone serves special attention. So-called spontaneous graft in the lower spine, calcified costal cartilage, pneumoperitoneum occurs with a long list of other calcifications in the abdominal aorta and in the iliac disorders. For example, air may penetrate from the

832 uterus, or it may derive from gas-producing bac- teria; intestinal perforation from carcinoma or trauma can occur; and gas can be found after ab- dominal operation for as long as 2 or 3 weeks. In the left lateral decubitus position, the air in a perforation will be seen as a thin, translucent area under the right lateral abdominal wall and between it and the liver (Fig. 4). The left lateral decubitus position is considered superior to the upright position on the natural pre- sumption that air, if present in the stomach, could escape only through the perforation. A recent ar- ticle by Woodruff and associates 14 describes use of a translateral view with the patient in Fowler's posi- tion. They claim 100 per cent effectiveness in dem- onstrating free air under the diaphragm with this technic. Clinically, boardlike rigidity is not always pres- ent.

Intestinal obstruction • Ileus results from a me- chanical block of the bowel or from inhibition of gastrointestinal motility. Adynamic ileus affects both the small and the large bowel simultaneously; it occurs after abdominal operation, with peritoni- tis, in pneumonia, after vertebral fracture, and as Fig. 4. Air-fluid level in left lateral decubitus position, with sen- tinel loop due to perforation of the posterior pylorus. Aspiration a terminal event in many acute abdominal diseases. yielded 1,500 cc. of fluid. The patient ultimately developed a It is a functional type of obstruction, possibly due left subdiaphragmatic abscess. to interference with the nervous mechanism which maintains peristalsis. Mechanical obstruction ( dynamic ileus) is sur- The appearance of the colon in mechanical small gically the more important of the two types. Intus- bowel obstruction is typically either contracted or susception is the chief cause of obstruction in in- completely collapsed, but the colon is not gas filled. fants, but it is rarely seen in patients beyond age However, this typical appearance is not always 10. In young adults, obstruction is most frequently found; occasionally some gas may be found in the the result of postoperative adhesions. In later life, cecum or the sigmoid even if the obstruction is it is more commonly caused by neoplasms. Neo- complete. This phenomenon is especially noted in plasms produce 90 per cent of colonic obstructions; the patient who has had an opiate, such as mor- about 8 per cent result from sigmoidal volvulus.15 phine, some hours before the x-ray examination. Under normal conditions, stasis does not occur Peritonitis and exudate in the abdomen are rec- in the gastrointestinal tract, and air is seen only in ognized as increased densities between gas-filled small amounts in the stomach and in the colon. The loops, the distance between which will exceed 3 appearance of even a small amount of gas in the mm. There is a tendency for the loops to become small intestine indicates either a mechanical or an adherent and fixed in position, so that on an erect adynamic obstruction to the normal flow. On the film one sees fixed loops scattered through the ab- other hand, it is rare for gas to be absent from the domen with fluid at various levels. With a persistent colon. In the presence of a colonic obstruction, the peritonitis, the mechanically dynamic bowel be- amount of gas in the colon is greatly increased. comes a paralytic, adynamic bowel, as a result of Unless the patient has recently vomited, the ab- the inhibitory impulses due to peritoneal irrita- sence of air in the stomach is strong evidence tion.'6 against a diagnosis of obstruction. Rectal gas is An alteration of the properitoneal fat line also rarely present in mechanical obstruction; but it is signifies exudate within the abdomen; however, ab- seen after enemas wherein air is introduced through sence of this sign does not exclude the presence a tubing. Cleansing enemas may produce confusing of an exudate. If exudate infiltrates the fat, the fluid levels in the colon. latter may have a blurred appearance or it may be The most common sites of small bowel obstruc- obscured completely. tion are in the right iliac fossa and in the pelvis. In mechanical ileus, fluid levels in two segments It is now commonly accepted that distended small of the same coil are at different heights as a result bowel in a stepladder pattern with "hairpin" turns of intestinal peristalsis; whereas in paralytic ileus is almost synonymous with small bowel obstruction the fluid levels are at the same level because peri- (Fig. 3). Fluid levels may be demonstrated in the stalsis has ceased. erect or the lateral recumbent positions; subse- How do we know whether a loop of bowel is quently, evidence of peritonitis becomes apparent. part of the large or small intestine? The jejunum

JOURNAL A.O.A., VOL. 60, JUNE 1961 833 and the ileum have no indented serosa, and the Adhesions • If the films are taken while symptoms jejunum has a coiled-spring appearance; the colonic are present, intra-abdominal adhesions may be seen serosa is indented by haustrae. If a fluid level is as fixed loops of small bowel. Partial obstruction, present, the bubble of air above the fluid has a due to adhesions, is found in ambulatory patients greater length than height; in addition, the valvulae with a vague history of occasional cramplike pains; conniventes are frequently seen. The air bubble in these patients will register normal temperatures the large intestine is of greater height than length; and normal leukocyte counts. 15 Usually there is a and the haustral formation is seen. history of previous abdominal surgery. However, The relative absence of large intestinal gas is an adhesions are usually very difficult to diagnose ac- almost constant finding in small bowel obstruction. curately on a survey film. As stated earlier, a roentgenogram which demon- At this point it might be worth commenting on strates fluid levels in dilated coils of small bowel is the use of the Miller-Abbott tube and the occa- pathognomonic of intestinal obstruction. There is sional need for the use of contrast media. Intuba- great unanimity of opinion on this point in the tion in the treatment of obstructing small intesti- literature.17 nal lesions allows aspiration of gas and fluid so In evaluation of fluid levels, the most important that the vicious cycle of bowel distention and in- erroneous source is a fluid level in the large intes- crease in secretion can be abated. Occasionally, tine due to retained enema. It is important that a fluoroscopic guidance is required to determine patient not be given enemas before abdominal whether or not the Miller-Abbott balloon is in the x-ray evaluation. Fluid levels are found in both stomach or in the duodenum. To determine this, an paralytic ileus and in mechanical ileus. At first, only easy method for localizing the balloon's position is distention, which is chiefly localized in the large through air injection. If the balloon is in the stom- bowel, is found. In fully developed paralytic ileus, ach, the gas bubble will go higher; if the balloon however, there are small bowel fluid levels which has passed the pylorus, air will accumulate in the correspond completely to the findings of mechanical duodenum.19 ileus. In paralytic ileus, however, there will always For many years, some surgeons objected to the be a meteoristic large intestine, which is rarely the oral administration of barium in cases of ileus; one case in obstruction of a mechanical nature. still sees this stated in current literature. The reason Mixed forms of ileus may occur in intraperitoneal for opposing the use of barium in the presence of abscesses, particularly in appendiceal abscess. Ob- obstruction is an idea that the contrast media will struction of the large intestine is characterized by inspissate and increase the degree of obstruction. a gradual distention of bowel and by formation of Apparently, according to Frimann-Dah1,2 the oppo- fluid levels in the parts of the large intestine proxi- site occurs. In occlusion, at least in the small intes- mal to the obstruction. When a simultaneous peri- tine, there will always be fluid proximal to the ob- tonitis exists or when the obstruction has been struction; as the barium descends it is diluted, present for a long time, the x-ray evidence of ileus gradually becoming thinner and thinner (ultimately will spread to the small bowel. becoming quite transparent). Even if the obstruc- By irritating the peritoneum, which produces an tion is in the large bowel, in most cases no ill inhibitory impulse on the digestive tract, any local- effects will ensue since here, also, fluid dilutes the ized inflammatory process can cause a localized barium suspension. Contrast medium can be of ileus. The "sentinel loop" is seen in acute gall- greatest importance for visualizing a regional in- bladder disease, acute appendicitis, acute pancreati- flammatory process or a mesenteric thrombosis. In tis, perforated ulcer ( Fig. 4), and appendiceal ab- the experience of one author, 2 barium given orally scess.18 If the abscess lies close to the peritoneum, in small amounts of 2 teaspoonfuls presents neither it may infiltrate and obscure the properitoneal fat a danger to the patient nor a complication to sub- line. sequent surgical procedures, whatever the existing ailment might be. Strangulating obstruction • A strangulation ileus is a condition in which the two limbs of a bowel Mesenteric thrombosis • A thrombus or an embo- loop and its mesentery are incarcerated so that the lus may occur anywhere in the mesenteric vessels. mesenteric vessels are either totally or partially The lesion appears more frequently in the arteries occluded. The strangulated loop will accumulate than in the veins; it is forty times more frequent gas only if the intestine has been partially obtu- in the superior than in the inferior mesenteric ar- rated—not at all in a closed loop. The gas, as pre- tery. It is rarely seen in persons under 40, and is viously mentioned, is mainly derived from swal- more frequent in men than in women. In nearly lowed air either in the small or large bowel. If all cases, the scout film shows the common feature partial strangulation exists, distinct gas and fluid of a distended small bowel, containing gas and levels will be seen. However, if complete strangu- fluid. Occasionally, there is also some large intes- lation is present, these signs will not be seen. tinal distention and evidence of peritoneal fluid." The tighter the strangulation, the more fluid and Embolism and thrombosis of the mesenteric ves- the less gas will be seen within the closed loop. In sels present typical pictures of obstruction, but addition, peritoneal fluid is found frequently in the error in interpretation is of little importance since pelvis, in the flanks, or between the loops. surgical intervention is indicated in either case.

834 Most of these patients give a history of having passed blood by rectum if the bowel is infarcted, and some are in a degree of shock. Recently, Nelson and Eggleston 2° stated that the findings of a rigid, edematous segment of bowel with a small, unspectacular collection of gas re- maining in a narrow, relatively straight or curvili- near lumen, without change in distribution in up- right or decubitus projections, is suggestive of mesenteric venous obstruction. In acute occlusion pain is excruciating, while in chronic occlusion it is dull. The findings in arterial or venous occlusion are that of a nonspecific ileus. The classic pattern is distended small and large bowel up to the splenic flexure. Occasionally, the "pseudotumor" sign is seen; this sign is due to a water density mass seen on plain films, as a result of a large amount of fluid in the infarcted lumen.

Enterocolitis • Enterocolitis with diarrhea may show fluid levels in the colon, but the diarrhetic condition in itself generally excludes the presence of intestinal obstruction. In usual cases, fluid levels may be present both in the lower part of the small intestine and in the colon. The arrangement of these levels and their usual short lengths are in Fig. 5. Mechanical ileus due to incarcerated right femoral hernia of 4 to 5 days duration. This film demonstrates the importance some ways so characteristic that the diagnosis can of including the pubes in a survey film. readily be made. This shows a multitude of small levels, one above the other in a staircaselike man- ner, situated in the colon. such as colonic atresia and imperforate anus. Large bowel distention may be great enough to obliterate Gallstone ileus • This condition comprises about the haustral pattern, and also the ileocecal valve 2 per cent of all types of mechanical obstruction. may become incompetent so as to allow small bowel Gallstones most frequently penetrate directly from distention. the gallbladder into an adjacent viscus; a secondary fistula nearly always results. Surprisingly enough, Volvulus • Volvulus includes all forms of torsion these encroachments take place nearly without clin- of the mesenteric axis, including those forms caused ical symptoms, and a history of an acute abdominal by a constriction of the lumen, strangulation of the episode is often lacking. vessels, or by both conditions simultaneously. Vol- The roentgenographic findings resemble those of vulus can occur in the stomach and small bowel, an obstructive ileus. It shows fluid levels and many but most frequently it involves the large bowel; dilated coils relatively late. In 50 per cent of cases, nearly half of all cases involve the sigmoid. The the gallstone can be seen on the film; frequently it most frequent finding is the presence of one (but is found in the area of the terminal ileum. Another usually two) greatly dilated sigmoidal loops, lying very important finding in this condition is a gas- upright and parallel in the abdomen. A lateral de- filled biliary tree. cubitus film may show fluid levels. In obstruction of the sigmoid, the prestenotic part is often rela- Obstruction due to hernia • Although inguinal tively slowly distended; whereas the more proxi- hernia is the most common type, strangulation is mal portions, the ascending colon and the cecum, relatively more frequent in femoral ( Fig. 5) and are greatly expanded by gas. This is because the in umbilical hernias. Incisional and umbilical her- cecum has thinner intestinal walls than does the nias are best demonstrated in a lateral projection by sigmoid. This explains the clinical experience that showing loops of bowel, which are dilated and ly- in an obstruction of the sigmoid, a tumorlike filling ing anterior to the abdominal wall. in the cecal area is palpable. Thus, in obstruction of the sigmoid, the proximal portion of the colon Mechanical obstruction of the large bowel • is the more distended. Obstructions due to adhesions and bands are rarely seen in the large bowel. On the other hand, tumor, Intussusception • Nearly 80 per cent of patients fecal impaction, volvulus, and intussusception with this condition are boys, and the symptoms (which are relatively infrequent in the small bowel) occur most frequently at the period when the are common causes of obstruction in the colon. change from breast feeding to mixed food occurs. Rarer etiologic factors are congenital malformations, The classical picture of these children (usually in

JOURNAL A.O.A., VOL. 60, JUNE 1961 835 their first year of life) shows symptoms of intermit- levels. This is seen in subphrenic and appendiceal ab- tent abdominal pains, vomiting, blood and mucous scesses. As a rule, however, it is noted that fluid and in the stool, and a palpable tumor. Laurell has gas do not lie within the intestinal tract. Difficulties noted that these children often have a remarkably often arise in deciding whether such collections of small liver or heart, caused by loss of fluid or per- gas are located within or outside the intestinal haps as an expression of the loss of blood. 2 The lumen. To decide this conclusively, examination roentgen diagnosis of intussusception is usually should be made in recumbent or in upright posi- based on films made both with and without a con- tion. When the abscess, with the patient in lateral trast medium. The lesion may show findings quite recumbent position, lies close to the lower flank, similar to that of an acute mechanical ileus. When gaseous intestinal loops ascend to the upper flank; it involves the terminal ileum or the proximal colon, correspondingly, the gas in the abscess remains an absence of the usual right lower quadrant cecal and is revealed as small irregular clearings within shadow occurs on the plain film. Occasionally, a the opacity. Such findings are nearly pathogno- soft tissue mass may be demonstrable. monic of an abscess. The most frequent pelvic abscesses originate from Acute appendicitis • The most frequent positive acute appendicitis or salpingitis. An early sign of finding on the survey film in acute appendicitis is an appendiceal abscess on the survey film is a dif- that of a peritoneal irritation. Small gaseous col- fuse, but relatively sharply outlined, density in the lections in the lower ileum and the cecum and fluid right iliac fossa. When the cecum or adjacent loops levels in both sections constitute roentgenographic of ileum contain gas, the marked impression caused appearance of peritoneal irritation. The most reli- by the infiltration may be observed—often fairly able finding is a fluid level in the cecum on a left well in films taken with the patient in a left lateral lateral recumbent film. recumbent position.

Abscess • Figure 6 shows an example of an abscess Acute • The most important findings demonstrated roentgenographically. Circumscribed on the survey film in acute gallbladder disease are abscesses resemble local densities, often with round- the demonstration of a positive stone shadow, local ed contours. If the abscess reaches the medial psoas distention of small or large bowel in the region of margins or the lateral retroperitoneal fat, these con- the gallbladder, and secondary changes in the peri- tours are effaced in relation to the size of the infil- toneal cavity or in the pleura. If the duodenum and tration. Gas-forming abscesses in the peritoneal the bulb are also distended with gas, an affection cavity may produce bubbles of gas lying above fluid of the pancreas or cholangitis is suggested.

Acute pancreatitis • Ordinary survey films of the abdomen taken with the patient in a supine position may show a greatly distended stomach and duo- denal bulb, the latter with or without fluid levels. The transverse colon and the small intestine, as well, are more or less distended with gas. The earliest finding in pancreatitis is the production of a segmental ileus. This may appear on the plain film as a "sentinel loop" of jejunum in the region of the pancreas. An elevated serum amylase value occurs in the first few hours of the disease, and is a valuable laboratory adjunct.

Abdominal tumors • Dermoid and ovarian cysts have already been described. In infants and chil- dren, according to Nice, Margulis, and Rigler,21 Wilms's tumor is the most common neoplasm of the abdomen. Neuroblastoma sympathicum is next most frequent in infants, and retroperitoneal teratoma is third. These are manifested as soft tissue masses, and are not usually diagnosed by survey films.

Roentgenographic findings in abdominal trauma Rupture of the liver • Hemorrhage into the peri- Fig. 6. Massive subhepatic abscess with incomplete obstruction toneal cavity may cause loss of normal outline, par- due to edema around previous colon anastomosis for ruptured tially or on its entire surface. Fluid may be found sigmoid diverticulum. along the right flank, as well as signs of peritoneal

836 irritation. When blood clots lie beneath the dia- Gratitude is expressed to Dr. T. C. Hobbs for his phragm, a deformity of the dome may occur. invaluable advice, which led me out of all sorts of alleys and more than once put me back on the Rupture of the spleen • In an excellent review broad highway. of the diagnosis of splenic rupture by Hylander, Miller, and Wilkins,22 the following findings were noted: A diffuse density develops around the spleen, with partial or general loss of outline. When larger 1. Curry, R. W.: Value of left lateral decubitus position in amounts of blood collect between the diaphragm roentgenologic diagnosis of acute abdominal disease. Surg., Gynec. Obst. 104:627-632, May 1957. and the spleen, the former is pushed upward and 2. Frimann-Dahl, J.: Roentgen examinations in acute abdominal the latter downward. Hematomas may also give a diseases. Charles C Thomas, Springfield, Ill., 1951. 3. Levitin, J.: Scout film of abdomen. Radiology 147:10-29, July characteristic impression upon the greater curva- 1946. ture of the stomach, and displace that organ to the 4. Meschan, I.: Roentgen signs in clinical diagnosis. W. B. Saun- ders Co., Philadelphia, 1956. right. In addition, the splenic flexure of the colon 5. Feldman, M.: Clinical roentgenology of digestive tract. Williams may also be displaced downward. Reflex gastric Wilkins Co., Baltimore, 1957. 6. Levine, S., and Solis-Cohen, L.: Survey film diagnosis of acute dilatation and ileus may also occur. surgical abdomen. Surg., Gynec. Obst. 78:76-82, Jan. 1944. 7. Leigh, 0. C., Jr.: liens associated with edema of bowel. Surg., Gynec. Obst. 75:279-284, Sept. 1942. Rupture of the kidneys • In about 50 per cent 8. Donahue, J. IC, Hunter, C., and Balch, H. H.: Significance of of cases, the perirenal hematoma is revealed as a fluid levels in x-ray films of abdomen. New England J. Med. 259:13- 15, July 3, 1958. diffuse density, obscuring the clear zone of fat 9. Hoyer, A.: Roentgen diagnosis of intestinal obstruction. Acta around the kidney. Large hematomas, extending radiol. 19:409-432, 1938. 10. Frimann-Dahl, J.: Roentgenologic examination of acute ab- medially, may bring about loss of psoas margin dominal lesions. Acta radiol. 20:438-451, 1939. outline. Scoliosis of the lumbar spine with convex- 11. Epstein, B.: Clinical radiology of acute abdominal disorders. Lea Febiger, Philadelphia, 1958. ity toward the unaffected side is usually found. As 12. Sante, L. R.: Principles of roentgenological interpretation. a result of the injury and the hematoma, meteor- Ed. 9. Edwards Bros., Ann Arbor, Mich., 1952. 13. Kelley, M. L., Jr., et al.: Significance of pancreatic calcifica- ism develops-a distention which may be very tion. New York J. Med. 57:721-730, Feb. 15, 1957. 14. Woodruff, J. H., Jr., and Simonton, J. H.: Radiologic diagnosis severe. If peritonitis is absent, no fluid levels are in abdominal trauma. Calif. Med. 91:197-200, Oct. 1959. observed. Intravenous urography yields a more 15. Requarth, W.: Diagnosis of acute abdominal pain. Year Book Publishers, Chicago, 1953. accurate diagnosis in these cases. 16. Alvarez, W. C., and Hosoi, K.: What has happened to unob- structed bowel that fails to transport fluids and gas? Am. J. Surg. 6:569-578, May 1929. Summary 17. Sussman, M. L., and Reich, L.: Roentgen findings in certain abdominal disorders. Am. J. Roentgenol. 76:127-131, July 1956. 18. Young, B. R.: Significance of regional or reflex ileus in Normal and abnormal findings on the routine scout roentgen diagnosis of cholecystitis, perforated ulcer, pancreatitis and abdominal film have been discussed in some detail. appendiceal abscess, as determined by survey examination of acute abdomen. Am. J. Roentgenol. 78:581-586, Oct. 1957. With a special stress on bowel obstruction, the 19. Jusztusz, G.: Easy method for determination of position of physiologic mechanisms underlying the basis of in- duodenal catheter. Magy. Radiol. 8:183, Aug. 1956. 20. Nelson, S., and Eggleston, W.: Findings on plain roentgen- terpretation of the abdominal findings have been ograms of abdomen associated with mesenteric vascular occlusion noted. Roentgenographic findings in the more com- with possible new sign of mesenteric venous thrombosis. Am. J. Roentgenol. 83:886-894, May 1960. mon disease entities have been briefly outlined. An 21. Nice, C. M., Jr., Margulis, A. R., and Rigler, L. G.: Simple attempt has been made to re-emphasize the value approach to roentgen diagnosis of abdominal tumors in infants and children. Am. J. Roentgenol. 75:977-993, May 1956. of the survey film in the diagnosis of acute abdomi- 22. Hylander, G. B., Miller, J. R., and Wilkins, F. M.: Diagnosis nal diseases. of rupture of spleen. J. Am. Osteop. A. 58:349-352, Feb. 1959.

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