Peripheral blood eosinophilia associated with gastrointestinal administration of iodinated contrast media

Computed tomography colonography for the practicing radiologist: A review of current recommendations on methodology and clinical indications

Colorectal cancer (CRC) represents one of the most relevant causes of morbidity and mortality in Western societies. CRC screening is actually based on faecal occult blood testing, and optical colonoscopy still remains the gold standard screening test for cancer detection. However, computed tomography colonography (CT colonography) constitutes a reliable, minimally-invasive method to rapidly and effectively evaluate the entire colon for clinically relevant lesions. Furthermore, even if the benefits of its employment in CRC mass screening have not fully established yet, CT colonography may represent a reasonable alternative screening test in patients who cannot undergo or refuse colonoscopy. Therefore, the purpose of our review is to illustrate the most updated recommendations on methodology and the current clinical indications of CT colonography, according to the data of the existing relevant literature.

Immediate and nonimmediate reactions induced by contrast media: incidence, severity and risk factors

Background

The pattern of the contrast media-induced adverse reactions has not been investigated extensively in Mexico.

Objective

To estimate the incidence and the degree of severity of the adverse reactions to contrast media, administered for the first time, in hospitalized subjects.

Methods

We studied 99 patients longitudinally on whom computed tomography with contrast media (iopamidol) was carried out. The adverse reactions were identified by clinical examination; subsequently, they were classified as mild, moderate and severe, following the Manual on Contrast Media version 9 guides, and as immediate and nonimmediate. In addition, the vital functions, oxygen saturation, serum creatinine levels and the total number of eosinophils were measured before and after the procedure.

Results

The incidence of immediate and nonimmediate adverse reactions was of 26.3% and 10.1%, respectively. The mild immediate reactions were 18 (69.2%), the most common being the sensation of warmth, nausea and pruritus; among the more delayed reactions, nephrotoxicity stood out (5.1%). The serum creatinine median showed no difference either before or after the intravenous injection of contrast media (p = 0.13); in contrast, there was a significant difference in the total number of eosinophils (p ≤ 0.001). The values of high baseline systolic blood pressure and the diminished baseline amounts in pulse oximetry were significantly related with any type of the adverse reactions to contrast media.

Conclusion

The incidence of the adverse reactions to contrast media was greater with respect to previous reports; the majority of these reactions were of the immediate type and of a mild nature. The risk factors that have mostly been implicated in the adverse reactions to contrast media could not be identified in our cohort.

Fluid tagging for CT colonography: effectiveness of a 2-hour iodinated oral preparation after incomplete optical colonoscopy

OBJECTIVE

To evaluate the distal extent and attenuation of bowel opacification achieved after administration of a single low volume dose of oral contrast 2 hours before computed tomographic colonography (CTC) after incomplete optical colonoscopy.

METHODS

This retrospective study included 144 patients undergoing CTC after incomplete colonoscopy from April 2006 to July 2008 at 2 separate medical centers. Each patient received 20 to 30 mL of diatrizoate meglumine and diatrizoate sodium solution 2 hours before being scanned.

RESULTS

The distalmost extent of opacification was: stomach/small bowel, n = 13; cecum, n = 2; ascending colon, n = 7; transverse colon, n = 19; descending colon, n = 14; sigmoid colon, n = 24; rectum, n = 65. The mean attenuation of each opacified segment was: cecum, 449 Hounsfield units (HU); ascending colon, 474 HU; transverse colon, 468 HU; descending colon, 421 HU; sigmoid colon, 391 HU; and rectum, 382 HU. In 103 (71.5%) patients, oral contrast reached the distal colon (descending colon, sigmoid colon, or rectum). The oral contrast did not reach the colon in only 13 (9.0%) patients.

CONCLUSIONS

Oral administration of a small volume hyperosmolar oral contrast agent 2 hours before CTC results in satisfactory colonic opacification in the majority of patients. Adding same-day fluid tagging in incomplete colonoscopy patients presenting for completion CTC should result in adequate fluid opacification for most of the colon, especially proximal segments not visualized at the time of incomplete colonoscopy.

CT colonography: same-day tagging regimen with iodixanol and reduced cathartic preparation

The purpose of the study was to test the tagging performance and patient's acceptance of a reduced cathartic preparation, based on iodixanol and PEG, administered to patients 3 h before the exam. One hundred and thirty-two asymptomatic patients were enrolled. As colonic cleansing we used PEG macrogol 3350. For fluid tagging iodixanol was orally administered 3 h before the exam, in a total dose of 50 mL mixed with 34.8 g of PEG in 750 mL of water. Image's review showed 446 segments (56.4%) clean of feces and 346 segments (43.6%) with feces. Untagged fluid was observed in 74/706 (10.5%) segments; inhomogeneous tagging in 129/706 (16%); the average density of fluid was 1054.74 UH in the cecum-ascending colon and 905.14 UH in the descending-sigmoid colon; the average difference of density between right and left colonic segments was 149 UH, and it was statistically significant (P = 0.016). No side effects related to the consumption of Movicol were reported. Very few side effects related to the tagging solution were reported: mild nausea in 7 (0.05%) patients, mild diarrhea in 10 (0.07%). An average rank of 9 points (SD +/- 1) on a 10-point scale (10 = no discomfort, 0 = severe discomfort) resulted from the self-administered questionnaire, showing an excellent acceptance of the preparation. Same day fluid tagging with iodixanol provides an optimal fluid tagging, it is completely tolerated by the patient, and it can be performed under medical control.