Evaluation of neutral oral contrast agents for assessment of the small bowel at abdominal staging CT

Hypersensitivity reactions after diagnostic nonvascular administration of iodine-based contrast media and gadolinium-based contrast agents and the role of the drug allergy specialist

The risk of hypersensitivity reactions (HSR) following nonvascular administration of contrast media (CM) for diagnostic studies is very low, likely due to minimal absorption into the systemic circulation. Most published individual cases of HSR after nonvascular CM administration are immediate reactions caused by ionic high-osmolar CM, few by nonionic low-osmolar CM, and none by gadolinium-based contrast agents. Measures to prevent recurrent HSR following nonvascular administration are similar to those recommended to prevent HSR after intravascular CM administration. Premedication as preventive measure has been abandoned, while switching to an alternative CM, preferably based on the results of an allergological analysis, is increasingly advocated. In selected scenarios, preventive measures may be minimized.

Comparison of the diagnostic accuracy of CT scan with oral and intravenous contrast versus CT scan with intravenous contrast alone in the diagnosis of blunt abdominal traumas

PURPOSE

Abdominal CT scan using oral and intravenous (IV) contrast is helpful in the diagnosis of intra-abdominal injuries. However, the use of oral and IV contrast delays the process of diagnosis and increases the risk of aspiration. It has also been shown that CT scan with IV contrast alone is as helpful as CT scan with oral and IV contrast and rectal CT scan in detecting abdominal injuries. Therefore, the present study aims to prospectively compare the diagnostic value of CT scan with oral and IV contrast versus CT scan with IV contrast alone in the diagnosis of blunt abdominal traumas (BATs).

METHODS

Altogether 123 BAT patients, 60 (48.8%) women and 63 (51.2%) men with the mean age of (40.4 ± 18.7) years who referred to the emergency department of Imam Khomeini Educational and Medical Center in Sari, Iran (a tertiary trauma center in north of Iran) from November 2014 to March 2017 and underwent abdominal CT scans + laparotomy were investigated. Those with penetrating traumas or hemodynamically unstable patients were excluded. The participants were randomly allocated to two groups: abdominal CT scan with oral and IV contrast (n = 63) and CT scan with IV contrast alone (n = 60). No statistically significant difference was found between two groups regarding the hemodynamic parameters, age, gender, injury mechanisms (all p > 0.05). The results of CT scan were compared with that of laparotomy results. The collected data were recorded in SPSS version 22.0 for Windows. Quantitative data were presented as mean and SD.

RESULTS

The sensitivity and specificity of CT scan using oral and IV contrast in the diagnosis of BATs were estimated at 96.48 (95% CI: 90.73-99.92) and 92.67 (95% CI: 89.65-94.88), respectively; while CT scan with IV contrast alone achieved a comparable sensitivity and specificity of 96.6 (95% CI: 87.45-99.42) and 92.84 (95% CI: 89.88-95.00), respectively.

CONCLUSION

CT scan with IV contrast alone can be used to assess visceral injuries in BAT patients with normal hemodynamics to avoid diagnostic delay.

Comparison of Mannitol, Water, and Iodine-Based Oral Contrast in the Evaluation of the Bowel by Multi-Detector Computed Tomography

Background and objectives

To perform contrast-enhanced computed tomography (CECT) of the abdomen with water, mannitol, or iodinated positive contrast as an oral contrast agent, and compare the distension and enhancement pattern of the bowel.

Methods

This was a prospective observational study conducted on 90 patients over a period of 12 months who were referred for CECT abdomen. Patients were randomly divided into three groups (30 each) and were given water, mannitol, or positive oral contrast before the CECT study. Quantitative and qualitative analysis of the bowel for distension, mural fold pattern, and enhancement was analyzed at various anatomical levels. A qualitative examination of bowel loops was done in the three groups by using a continuous 4-point scale.

Results

The mean distension at the duodenum was 1.89 ± 0.33 cm (mean ± SD) with water, 2.28 ± 0.36 cm with mannitol, and 2.01 ± 0.33 cm with positive oral contrast. Overall, maximum luminal distension was seen at the level of the duodenum, followed by the jejunum across all the groups. Bowel characteristics were far superior in the mannitol group compared to water and positive oral contrast at all anatomical levels.

Conclusion

Small bowel distension was excellent with mannitol, followed by positive oral contrast, and least with water. Mural characteristics and enhancement patterns were better with mannitol as compared with water and with positive oral contrast.