Extraluminal Gas Research Articles

Blunt trauma to the gastrointestinal tract: CT findings with small bowel and colon injuries.

The CT diagnosis of bowel injury is difficult and warrants an organized approach. Careful scrutiny of CT images for extraluminal gas or fluid and bowel wall thickening is required. Review of images of the entire abdomen and pelvis using lung window settings is recommended, followed by the analysis using soft tissue window settings. Specific search for extraluminal fluid collections with a triangular or matted appearance will help detect bowel injury.

Abdominal x rays made easy: abnormal extraluminal gas

This month Ian Bickle and Barry Kelly look at identifying abnormal extraluminal gas on plain abdominal films, in the third part of our series on abdominal radiographs

Gastrointestinal complications of laparoscopic Roux-en-Y gastric bypass surgery: clinical and imaging findings.

To report the complications and imaging findings in a large group of patients who underwent Roux-en-Y gastric bypass (GBP) surgery. Four hundred sixty-three patients were evaluated for upper gastrointestinal (GI) complications following Roux-en-Y GBP surgery. Major complications were those that required surgical or radiologic intervention and minor complications were those that resolved spontaneously. The time from surgery to complication and findings from upper GI series and computed tomography (CT) of the major complications and minor leaks were reviewed. Forty-four patients had 56 major complications: 23 small-bowel obstructions (14 internal hernias and nine adhesions), 16 major leaks, 15 anastomotic strictures, and two fistulas. There were 13 minor leaks and 18 other complications. Internal hernias were late complications and had a variety of findings at upper GI series and CT. Leaks were early complications and usually originated from the gastrojejunal anastomosis; findings from upper GI series and CT demonstrated extraluminal gas, contrast material, or both. Anastomotic strictures were late complications and were diagnosed at upper GI series with rounded dilation of the pouch and delayed emptying. Upper GI complications that required intervention occurred in 9.5% of patients. CT and upper GI series can depict most major complications.

Role of duodenography in the diagnosis of blunt duodenal injuries.

The differentiation of duodenal perforation from duodenal hematoma is not always possible with computed tomography (CT). Our diagnostic guideline has included duodenography to investigate CT findings of periduodenal fluid or wall thickening. However, the utility of duodenography as a diagnostic study in blunt abdominal trauma is not defined. We evaluated duodenography as a diagnostic test in patients with suspected blunt duodenal injuries (BDIs). During a 10-year period, 96 patients out of 25,608 trauma admissions had CT findings of possible BDI and underwent duodenography. Demographic and clinical data, diagnostic methods, and management were derived from prospectively collected data. CT and duodenography studies were reviewed and correlated with surgical findings and outcome. All CT scans were obtained with intravenous contrast; oral contrast was used in 32 patients. Duodenography was analyzed using the 2 x 2 method and Bayes theorem. Indications for duodenography included periduodenal fluid without extravasation (76%), abnormal duodenal wall thickening (16%), and retroperitoneal extraluminal gas (5%). Eighty-six duodenography studies were reported as normal, six were consistent with hematoma, one was indeterminate, and only three revealed extravasation. Two of these three patients with duodenal perforation had retroperitoneal extraluminal air. Only one patient underwent exploration on the basis of duodenography. No blunt duodenal perforation was diagnosed by CT. Overall, duodenography had sensitivity of 54% and specificity of 98%. For BDIs requiring repair, duodenography sensitivity was only 25%; the false-negative rate was also 25%. Retroperitoneal extraluminal air was a useful sign of duodenal perforation, occurring in two of three patients with BDI and only in one without BDI (p < 0.001). Duodenography has a low sensitivity in patients with suspected BDI by CT findings and is of minimal utility in diagnostic evaluation. Retroperitoneal extraluminal air seen on CT is an important sign of BDI requiring surgical repair.

IDIOPATHIC PERFORATION OF THE SIGMOID COLON WITH A LARGE DEFECT OF MUSCULAR LAYER

A 29-year-old man was admitted to another hospital because of lower abdominal pain and anal pair that started suddenly a day before and was referred to the hospital for the progressing pain. Physical examination showed tenderness and muscular rigidity on the lower part of the abdomen and laboratory studies showed a little inflammatory change. There was no previous history of trauma or disease. Chest and abdominal plain X-ray film showed no free air below the diaphragm or intestinal gas, however abdominal CT scan revealed the extraluminal gas around the Sigmoid colon. With a diagnosis of peritonitis due to perforration of the bowel, the patient underwent on emergentcy laparotomy. There wat a thin part in the bowel wall of Sigmoid colon, 3×4cm in diameter, which had several perforations Histologic examination of the perforation's margin showed that the menbrane was sharply cut off without indentation and muscular layer was aparted by the depression of subserosal fat tissue and there were some inflammatory cell infiltrations without necrosis, granulation, nor microabscess. The hist-logical diagnosis was identical to the category of idiopathic perforation of the colon. This case is considered rare in that the perforation come about after the laceration of muscular layer because the size of perforation was smaller than that of the laceration of muscular layer.

Computed Tomography Scanning for the Diagnosis of Perforated Appendicitis

The optimal initial treatment for perforated appendicitis may be nonoperative. For this reason it is important to be able to reliably distinguish between acute and perforated appendicitis. CT scanning has been shown to be highly accurate for the diagnosis of appendicitis, but it has not been specifically evaluated for perforated appendicitis. Our objective was to evaluate CT for the diagnosis of perforated appendicitis. Our study population comprised 84 patients who underwent appendectomy between 1993 and 1997 and who had CT scanning performed preoperatively. Medical records were reviewed retrospectively. CT scans were reviewed in a blinded fashion. CT findings were correlated with pathologic and clinical factors. Sixteen patients with acute appendicitis, 59 patients with gangrenous or perforated appendicitis, and 9 patients with normal appendices or other diagnoses were evaluated. For patients with pathologic documentation of appendicitis, CT findings that independently predict perforation or gangrene included abscess (P<0.001), phlegmon (P<0.001), extraluminal gas (P = 0.01), and terminal ileal wall thickening (P = 0.03). CT findings of an abscess, extraluminal gas, or phlegmon have a sensitivity of 92 per cent, specificity of 88 per cent, positive predictive value of 96 per cent, and negative predictive value of 74 per cent for perforated or gangrenous appendicitis. We conclude that CT can reliably distinguish between acute and perforated appendicitis.

Pathologic gas collections on abdominal computed tomography: Differential diagnosis and physiologic correlation

Abdominal computed tomography is often the critical step in the evaluation of patients presenting in the emergency department with abdominal pain and/or suspected intra-abdominal infection. Gas is normally found in the stomach, small bowel, colon, rectum, and occasionally the appendix. However, extraluminal gas collections can be identified on abdominal radiographs or computed tomographic examinations, and their presence often suggests specific pathology. Knowledge of different intra-abdominal pathologic gas collections and the underlying physiology contributing to each is important in understanding the clinical significance of each entity. The spectrum of intra-abdominal gas collections, as well as their clinical significance, will be described.

Leiomyosarcoma of the esophagus: radiographic findings in 10 patients.

Leiomyosarcomas of the esophagus are rare malignant smooth-muscle tumors that have been described only anecdotally in the radiology literature. The objective of this study was to evaluate the clinical and radiographic findings of this unusual lesion. A search of the radiology archives of the Armed Forces Institute of Pathology revealed 10 cases of esophageal leiomyosarcomas. Clinical and radiographic findings were reviewed retrospectively. All but one patient presented with dysphagia. The average duration of the dysphagia was 6.7 months, but five patients had dysphagia for 3 or fewer months. Frontal chest radiographs revealed a mediastinal mass in five patients. Barium studies revealed intramural lesions in six patients, intraluminal lesions in two, and infiltrative lesions in two. The intramural Lesions all had large exophytic components, and three contained ulceration or tracking. One of the intraluminal lesions appeared as a polypoid expansile mass and the other, as a smooth expansile sausage-shaped mass mimicking a fibrovascular polyp. CT revealed a mass involving the esophagus in five patients; three of these patients had heterogeneous lesions containing large exophytic components, central areas of low density, and extraluminal gas or contrast material within the tumor. In two patients, MR imaging revealed large masses that were isointense with skeletal muscle on T1-weighted images and hyperintense on T2-weighted images. Our experience suggests that esophageal leiomyosarcomas have radiographic findings similar to those of leiomyosarcomas elsewhere in the gastrointestinal tract. Esophageal leiomyosarcomas have a better prognosis than squamous cell carcinomas and are often amenable to surgical cure.

Pneumomediastinum: old signs and new signs.

Pneumomediastinum, also known as mediastinal emphysema, represents extraluminal gas in the mediastinum. Pneumomediastinum can lead to pneumothorax, pneumopericardium, pneumoperitoneum, or pneumoretroperitoneum. There are many causes of pneumomediastinum (Table 1) and several radiographic signs: pneumopericardium, continuous diaphragm sign, continuous left hemidiaphragm sign, Naclerio's V sign, V sign at confluence of brachiocephalic veins, ring-around-the-artery sign, thymic spinnaker-sail sign, and extrapleural air sign. We review the common and uncommon signs of pneumomediastinum and present some new signs. We also address the problem of distinguishing pneumomediastinum from pneumothorax and pneumopericardium.

Duodenal injuries caused by blunt abdominal trauma: value of CT in differentiating perforation from hematoma.

Traumatic duodenal perforation requires emergent surgery, whereas duodenal hematoma can often be treated nonsurgically. We assessed the CT findings in patients with blunt duodenal trauma to determine if CT can be used to differentiate these two duodenal injuries. Seven consecutive patients with blunt duodenal trauma (three with perforation, four with hematoma) who underwent CT as part of their initial diagnostic evaluation were included in the study. All three perforations and one of four hematomas were surgically proved. Diagnoses of duodenal hematoma in the other three patients were based on typical features on upper gastrointestinal studies and complete resolution of clinical findings after conservative treatment. The CT scans were retrospectively reviewed without knowledge of the specific type of duodenal injury, and the findings were correlated with the results of the gastrointestinal studies and surgical findings. CT showed extraluminal gas or extravasated oral contrast material or both in the right anterior pararenal space in all three patients with duodenal perforation and in none of the patients with duodenal hematoma. Thickening of the duodenal wall and fluid in the right anterior pararenal space were seen in both groups of patients. Although the number of patients in the study was small, the results suggest that CT may be useful in differentiating duodenal perforation from hematoma without perforation. Extraluminal gas or extravasated oral contrast material or both were seen in the right anterior pararenal space in all three patients who had perforation and in none of the patients who had hematoma alone.

Die nekrotisierende Enterocolitis - Analyse einer Erkrankungsserie

During a period of 25 months 11 newborns treated at the children's university hospital of Münster (0.8%) underwent laparotomy for necrotizing enterocolitis (NEC). The cases appeared sporadically without forming "clusters" typical of infectious etiology. 10 of 11 cases were premature infants (median birth weight 1280 g) stressing the predisposing role of immaturity. Ischemic events occurred in all patients prior to the onset of symptoms. The introduction of surfactant-therapy during the study period did not influence the incidence apparently. Ultrasonography was superior to radiology with regard to detection of extraluminal gas. We differentiated two types of clinical courses (3 acute and 8 protracted). In 5 cases we noticed a relapse of clinical symptoms after uptake of oral feeding. 3 newborns died with septic shock. The median hospitalisation time was 88.5 days in the 8 survivors. Enterostomy was replaced by definite anastomosis after 67.5 days (median). Median daily weight gain was 16.6 g. Late complications like permanent stenoses of short bowel syndrome were not observed. Early surgical intervention according to the general rules of abdominal surgery seems important even in very low birth weight infants.

Uncomplicated acute diverticulitis of the cecum and ascending colon: sonographic findings in 18 patients.

To determine the sonographic features of uncomplicated acute diverticulitis of the cecum and ascending colon, the sonographic findings in 534 patients who presented with right lower quadrant pain were reviewed. Of these, 18 patients had uncomplicated acute diverticulitis of the cecum and ascending colon. The diagnosis was confirmed by surgery (one patient), clinical course (17 patients), CT (eight patients), or contrast enema (11 patients). On sonography, a round or oval focus of varying echogenicity, which protruded from a segmentally thickened colonic wall and was surrounded by a hyperechoic area, was seen in all 18 patients. These were hypoechoic foci (12 patients), hypoechoic foci with internal strong echoes (three patients), and echogenic shadowing foci with surrounding hypoechoic bands (three patients). Extraluminal gas (one patient) and thickening of lateroconal fascia (six patients) were seen also. Findings of enlarged appendix, frank abscess, and ascites were absent. All patients, including the one who had laparotomy, were successfully treated medically for diverticulitis. Of 515 patients without diverticulitis, in only one patient with acute appendicitis did sonography show a hypoechoic protruding focus. Our experience indicates that the major sonographic finding in patients with uncomplicated acute diverticulitis of the right colon is a hypoechoic round or oval focus protruding from a segmentally thickened colonic wall.

Ileal J pouch: radiologic evaluation in patients with and without postoperative infectious complications.

The authors studied the ileograms and computed tomographic (CT) examinations of 18 patients who had undergone surgical construction of an ileal J pouch and ileoanal anastomosis; 10 had developed postoperative infectious complications and eight had not. The initial ileograms obtained 4 weeks postoperatively proved to be unhelpful in predicting future infectious complications, showing abnormalities in only two of 10 patients. Ileography and CT performed at the time of the complications showed abnormalities in eight of nine and nine of 10 patients, respectively. Ileographic abnormalities in patients with abscesses included extravasation of contrast material, extraluminal gas collections, thickening of ileal pouch folds, and extrinsic mass effect on the pouch. CT findings included thickening of the pouch and/or rectal walls, streaky areas of soft-tissue attenuation within the ileal pouch mesentery and perirectal fat, and areas of soft-tissue attenuation or fluid attenuation in the peripouch region. CT was more valuable in depicting the site and extent of abscess formation before surgical or percutaneous drainage.

Pancreatic phlegmon: What is it?

In a retrospective study of 264 patients with acute pancreatitis, 22 were identified as having phlegmon by combined radiologic and clinical criteria. The radiologic criteria consisted of demonstration of abnormal lesion on computed tomography scan which was composed of masses of mixed density, free of extraluminal gas and lacking a well-defined wall. The clinical criteria was that the clinical course was free of sepsis. Half of the group thus identified had severe pancreatitis as defined as having three or more poor prognostic signs. Fever, leukocytosis, and serum amylase elevation persisted for a longer period than usual. Complication was infrequent but the lesion could persist for 3 to 4 months without producing symptoms. This is a relatively benign condition and surgery should be avoided.

The sensitivity of plain films for detecting perforation in children with appendicitis.

The plain films of 37 patients under age 18 with surgically and pathologically proven non perforated (16/37) and ruptured (21/37) appendicitis were reviewed in order to determine the ability of the plain film to specify perforation. Perforation was suggested when one or more of the following six findings were clearly defined: 1. Acute small bowel obstruction. 2. Extraluminal gas. 3. Mass in the right lower quadrant. 4. Colon cut-off sign at the hepatic flexure. 5. Fecalith. 6. Obliteration of the pelvic fat planes. This approach resulted in a sensitivity of 80% and a specificity of 94%, with the only false positive for perforation occurring in a patient with a fecalith. In five patients, extraluminal gas produced a triangular accumulation in the right flank which could be distinguished from intraluminal bowel gas on the supine or prone film.

Upper abdomen: CT findings following partial hepatectomy.

The appearance on computed tomographic (CT) scans of the upper abdomen after partial hepatectomy is complex. The findings expected at CT should not be confused with those of surgical complications, such as abscess, biloma, or hematoma. The findings on CT scans and the records of 17 patients who had undergone partial hepatectomy for malignancy were reviewed. Operations included wedge resection, left medial and lateral segmentectomies, left lobectomy, right subsegmentectomy, right lobectomy, and extended right lobectomy (trisegmentectomy). When partial hepatectomy had been performed with no complications, findings at CT included a small region of low attenuation at the surgical margin, probably due to transient accumulation of blood and bile; a right pleural effusion; extraluminal gas; shift of abdominal organs; hepatic regeneration; and fat attenuation at the resection margin representing the omental patch placed at surgery. Findings associated with surgical complications--such as abscess, biloma, and hematoma--included large or high-attenuation perihepatic and subphrenic fluid collections that did not conform to the resection margin.

Upper abdominal trauma: pitfalls in CT diagnosis.

Medical records and computed tomographic (CT) scans of 83 patients with upper abdominal trauma were retrospectively reviewed to determine errors in diagnosis using CT. Patients with possible pancreatic injury, small bowel perforation, or injury to an occult malignancy represented the most difficult diagnostic cases. A false-positive diagnosis of pancreatic injury occurred in seven of 77 patients (9%) and represented the most frequent error in the series. In three patients with subsequently surgically proved small bowel perforation, one duodenal and two proximal jejunal, the injuries were not correctly diagnosed on CT scans. In retrospect, positive CT findings were present in the case of duodenal rupture. Additionally, in two patients, duodenal rupture was suspected based on CT findings of extraluminal gas and fluid near the duodenum, but both cases were proved normal at surgery. The series included three patients with trauma involving unsuspected tumors in the liver, kidney, and stomach.

Computed tomographic detection of gas within spontaneously necrotic tissue

Computed tomography (CT) is a widely accepted modality for the detection, localization, and potential therapeutic drainage of abdominal abscesses. The CT demonstration of extraluminal gas within the abdomen usually signifies the presence of an abscess. We report two cases of nonpurulent spontaneous tissue necrosis which simulated a gas containing abscess on CT. The significance of a gas-containing mass detected by CT must be: interpreted cautiously since this appearance is not necessarily pathognomonic of a drainable abscess. Confirmation of purulent material within a suspected abscess collection requires documentation by percutaneous aspiration or surgery.

Extraluminal gas in the upper abdomen.

Gangrene de la vesicule biliaire due a une embolie apres arteriographie abdominale chez un homme de 45 ans. La radiographie sans preparation montre la presence de gaz dans les voies biliaires et les parois de la vesicule

Duodenal perforation in childhood dermatomyositis

Perforation of the duodenum is an uncommon, but serious complication which may occur in children with dermatomyositis. In this disease vasculitis may involve the bowel to a variable extent and result in radiologic manifestations of intestinal injury ranging from benign pneumatosis intestinalis to signs of bowel perforation. We report two children with dermatomyositis in whom perforation of the second portion of the duodenum occurred. This serious complication should be considered in any child with dermatomyositis when extraluminal gas is suspected on abdominal radiographs.