Diagnosis of intestinal injuries by computed tomography and the use of oral contrast medium

Multi detector computed tomography in the diagnosis of bowel injury

Bowel Injuries are uncommonly associated with traumatic abdominal injuries. However, they are associated with significant morbidity and mortality and require operative intervention unlike solid organ injuries. Hence, early diagnosis is of paramount importance. Computed tomographic (CT) scan is a well-established and highly accurate imaging modality for the detection of solid organ injury after blunt abdominal trauma. However, its role in diagnosing hollow viscus injury remains controversial. The aim of our study was to analyze the accuracy of multidetector CT (MDCT) in the diagnosis of bowel injury. Imaging features of surgically proven cases of bowel injury were identified over 8-year period (i.e., from January 2003 to December 2010) and were retrospectively analyzed. There were 32 patients with age range of 3-90 years. There was only one female. Sensitivity of various CT signs specific to bowel injury (i.e., extravasation of contrast and discontinuity of bowel wall) was 15.62, and 28.12%, respectively. While that of signs suggestive of bowel injury were pneumoperitoneum, 62.5%; gas in the vicinity, 40.62%; bowel wall hematoma, 21.87%; bowel wall thickening, 75%; ascites, 78.12%; mesenteric hematoma, 46.87%; and mesenteric stranding, 40.62%. Based on the major and minor signs, a diagnosis of bowel injury could be made in all patients except one. The minor signs showed a higher sensitivity than the major signs. Hence, we recommend that multidetector CT should be used as the modality of choice in case of patients with suspected bowel injury. We also suggest that the minor signs should be given as much importance as the major signs.

Hollow viscus injury

BACKGROUND

Hollow viscus injuries are uncommon and occur in approximately 1% of all blunt trauma patients.

DISCUSSION

These injuries are often not suspected and are difficult to diagnosis. Morbidity and mortality are high, and a negative abdominal computed tomography is not sufficient to rule out these injuries in certain clinical scenarios.

CONCLUSION

Using a case-based approach, the epidemiology and diagnostic pathways to manage hollow viscus injuries are reviewed.

Computed tomography without oral contrast solution for blunt diaphragmatic injuries in abdominal trauma

OBJECTIVE

The aim of this study was to estimate the sensitivity, specificity, and positive predictive value (PPV) of computed tomography (CT) without oral contrast for diaphragm injuries (DIs) in blunt abdominal trauma.

METHODS

We prospectively enrolled 500 consecutive "trauma-one" patients who received CT imaging and interpretation (CT-Read1) of the abdomen within 45 minutes of their arrival from July 2000 to December 2001. All patients were imaged without oral contrast but with intravenous contrast. Computed tomographic images were reviewed within 24 hours of admission by research radiologists (CT-Read2) blinded to CT-Read1. True DIs were determined hierarchically by either laparotomy or autopsy.

RESULTS

There were 9 patients with laparotomy or autopsy-proven blunt DIs; 8 of these injuries involved the left hemidiaphragm. The CT-Read1 correctly detected only 6 of 9 blunt DIs, thus missing 3 DIs. One of these involved the right hemidiaphragm, whereas the other 2 were left sided. There were no false-positive findings with CT-Read1 for blunt DI. The sensitivity and specificity of CT imaging with respect to DI were 66.7% (95% CI, 29.9%-92.5%) and 100% (95% CI, 99.2%-100%), respectively. The PPV for the test was 1.00 (95% CI, 0.65-1.00).

CONCLUSION

Although the low number of blunt DIs in this study limits its general applicability, CT imaging of the diaphragm without oral contrast appears to perform within the range of reported imaging techniques using oral contrast. Still, CT scanning appears to have an unsatisfactorily low sensitivity to be reliably used in eliminating the diagnosis of blunt DI.

Blunt Abdominal Trauma: Performance of CT without Oral Contrast Material

PURPOSE

To retrospectively evaluate multi-detector row computed tomography (CT) without oral contrast material for depiction of bowel and mesenteric injuries that require surgical repair in patients with blunt abdominal trauma.

MATERIALS AND METHODS

The investigational review board approved the study. Informed consent was waived. CT reports for October 2001 to September 2003 were reviewed and 1082 patients were identified who had undergone abdominopelvic CT with a multi-detector row scanner and without oral contrast material. Findings were divided into four categories: negative, solid organ injury with or without hemoperitoneum, free fluid only, and suspected bowel or mesenteric injury. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated by comparing CT findings with laparotomy reports and hospital course.

RESULTS

CT findings were no intraabdominal injury (n = 932), solid organ injury only (n = 102), free fluid only (n = 34), and suspected bowel or mesenteric injury (n = 14). CT findings in patients suspected of having bowel or mesenteric injury were pneumoperitoneum with other secondary findings (n = 4), mesenteric hematoma and bowel wall abnormality (n = 2), mesenteric hematoma only (n = 4), and bowel wall thickening only (n = 4). In 11 patients, bowel or mesenteric injury was proved surgically. Thus, the study included 1066 true-negative, nine true-positive, two false-negative, and five false-positive results. Based on these data, sensitivity was 82% (95% confidence interval [CI]: 52%, 95%), specificity was 99% (95% CI: 98%, 99%), positive predictive value was 64% (95% CI: 39%, 83%), and negative predictive value was 99% (95% CI: 98%, 99%) for depiction of bowel and mesenteric injuries.

CONCLUSION

Multi-detector row CT without oral contrast material is adequate for depiction of bowel and mesenteric injuries that require surgical repair. Results are comparable with previously reported data for single-detector row helical CT with oral contrast material.

Computed tomographic scanning without oral contrast solution for blunt bowel and mesenteric injuries in abdominal trauma

BACKGROUND

Computed tomographic (CT) scanning using intravenous and oral contrast material has traditionally been advocated for the evaluation of intra-abdominal injury, including blunt bowel and mesenteric injuries (BBMIs). The necessity of oral contrast in detecting these injuries has recently been called into question. The purpose of this study was to determine the sensitivity and specificity of CT scanning without oral contrast for BBMIs.

METHODS

We prospectively enrolled 500 consecutive blunt trauma patients who received CT imaging and interpretation (CT-Read1) of the abdomen from July 2000 to November 2001. All patients were imaged without oral contrast, but with intravenous contrast. CT images were reviewed within 24 hours of admission by a research radiologist (CT-Read2) blinded to CT-Read1. For study purposes, true BBMI was determined to be present if either laparotomy or autopsy identified bowel or mesenteric injury, or both CT-Read2 and the hospital discharge summary described bowel or mesenteric injury. Three-month telephone follow-up was also completed.

RESULTS

CT-Read1 detected 19 of 20 bowel and mesenteric injuries. CT-Read1 missed one duodenal perforation. There were two patients with false-positive interpretations of CT-Read1 for bowel injury. The sensitivity and specificity of CT imaging for the detection of BBMIs were 95.0% and 99.6%, respectively.

CONCLUSION

CT imaging of the abdomen without oral contrast for detection of BBMIs compares favorably with CT imaging using oral contrast.