CT vs Contrast CT
Date First Published:
July 17, 2006
Last Updated:
July 19, 2006
Report by:
Gareth Lock, medical student (manchester royal infirmary)
Search checked by:
Gareth Lock, manchester royal infirmary
Three-Part Question:
In [blunt abdominal trauma patients] are [CT scans using oral contrast better than conventional CT scans] at [identifying intra-abdominal injury]?
Clinical Scenario:
Following an RTA, the female driver of one of the vehicles is stretchered into the accident and emergency department, complaining of epigastric pain. She displays the "seatbelt sign", her BP is >100mmHg and her pulse rate is 95bpm. The decision is made to CT scan her abdomen, and the use of oral contrast solution is debated between two registrars in the resuscitation area. One advocates its use, arguing that extravastion will be more easily spotted. The other suggests that an unacceptable delay will be cause by its administration. Should oral contrast be used in this situation?
Search Strategy:
OVID Medline, EMBASE and CINAHL interfaces
Search Details:
{[exp Multiple Trauma OR exp Child OR exp Middle Aged OR exp Accidents, Traffic OR exp Adult OR exp Appendicitis OR exp Wounds, Nonpenetrating OR exp Tomography, X-Ray Computed OR exp Abdominal Injuries OR exp Adolescent OR exp Pancreas OR exp Hospitalization OR exp Pancreatic Neoplasms OR exp Abdomen OR exp Liver Neoplasms OR exp Abdomen, Acute OR exp Gastrointestinal Diseases] AND [exp Image Enhancement OR exp Tomography, X-Ray Computed OR Tomography, Spiral Computed OR exp Contrast Media]
Outcome:
OVID Medline produced a total of 94 papers, of which 3 were relative to the three part question
EMBASE produced a total of 68 papers, of which none were relevant to the three part question
EMBASE produced a total of 68 papers, of which none were relevant to the three part question
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Oral contrast with computed tomography in the evaluation of blunt abdominal trauma in children Shankar, K R. Lloyd, D A. Kitteringham, L. Carty, H M 17/07/2006 UK | 101 children who underwent CT between 1993 and 1997. Median age 9.5 (range 1.5-16.5 years) | Retrospective cohort study. Evidence level 2+ | True positive CT scan (no contrast) | 17/44 - 39% | Only four patients diagnosed with intestinal injury to assess the efficacy of oral contrast - small sample size. No statistical tests carried out. Retrospective data |
| False positive CT scan (no contrast) | 0/44 | ||||
| True negative CT scan (no contrast) | 26/44 - 59% | ||||
| False negative scan (no contrast) | 1/44 - 2.2% | ||||
| True positive CT scan (contrast) | 16/60 - 28% | ||||
| False positive CT scan (contrast) | 1/60 - 1.7% | ||||
| True negative CT scan (contrast) | 42/60 - 70% | ||||
| False negative scan (contrast) | 1/60 - 1.7% | ||||
| Oral contrast solution and computed tomography for blunt abdominal trauma: a randomized study Stafford RE. McGonigal MD. Weigelt JA. Johnson TJ 17/07/2006 UK | 199 patients receiving oral contrast, 195 patients not receving oral contrast for blunt abdominal trauma. All patients over 18 years of age. | RCT Evidence level 1+ | Oral contrast group sensitivity, specificity for solid organ injury | Sensitivity 84.2% Specificity 94% | Non-blinded control trial |
| Oral contrast group sensitivity, specificity for intestinal perforation | Sensitivity 86% Specificity 100% | ||||
| Non-oral contrast group sensitivity, specificity for solid organ injury | Sensitivity 88.9% Specificity 51.7% | ||||
| Non-oral contrast group sensitivity, specificity for intestinal perforation | Sensitivity 100% Specificity 100% | ||||
| Effect of oral contrast administration for abdominal computer tomography in the evaluation of acunt blunt trauma Tseng B.D. et al 17/07/061 UK | 248 patients having CT scan between June 1988 and November 1993, of which 70 CT cases were reviewed. | Retrospective cohort study 2+ | Intestinal injury | 0/21 intestinal injuries found on laparotomy were found on contrast CT scanning. | Retrospective Only 70 of 124 CT scans were evaluated. No control group. Attribution of vomiting to oral contrast may be erroneous. |
| Pancreatic injury | 3/6 pancreatic injuries found on laparotomy were missed on contrast CT scanning | ||||
| Vomiting | 23% patients vomited - attributed to oral contrast use - one documented case of aspiration | ||||
| Liver and Spleen injury | 100% accuracy |
Author Commentary:
More large multicentre prospective control trials are required to assess the efficacy of contrast CT scanning in the evaluation of blunt abdominal trauma. Many studies had relatively small sample sizes.
Bottom Line:
The use of oral contrast in most cases of blunt abdominal trauma is unwarranted, with delayed time to diagnosis, increased chance of aspriation. It should only be used if intestinal injury is suspected, and even then only with adequate airway management
References:
- Shankar, K R. Lloyd, D A. Kitteringham, L. Carty, H M. Oral contrast with computed tomography in the evaluation of blunt abdominal trauma in children
- Stafford RE. McGonigal MD. Weigelt JA. Johnson TJ. Oral contrast solution and computed tomography for blunt abdominal trauma: a randomized study
- Tseng B.D. et al. Effect of oral contrast administration for abdominal computer tomography in the evaluation of acunt blunt trauma