June 2010 issue of Radiology has published a very significant article, that with wide-ranging implications.
CECT requests are rampant without any definite indications as most studies can be completed without contrast and studies needing contrast usually also need an MRI scan later; so why not dispense with it altogether.

The authors, Loh et al have found 14.3 % patients developing delayed reactions after CECT using Iohexol, which is definitely very high and probably unaccetable.


Delayed Adverse Reaction to Contrast-enhanced CT: A Prospective Single-Center Study Comparison to Control Group without Enhancement

Shaun Loh , MD , MBA
Sepideh Bagheri , MD
Richard W. Katzberg , MD
Maxwell A. Fung , MD
Chin-Shang Li , PhD
Radiology: Volume 255: Number 3—June 2010


Purpose: To prospectively assess the incidence of delayed adverse reactions (DARs) in patients undergoing contrast material–enhanced computed tomography (CT) with the low osmolar nonionic contrast agent iohexol and compare with the incidence of DARs in patients undergoing unenhanced CT as control subjects.
Materials and Methods:
Institutional review board approval and informed written consent for this prospective study were obtained. The study was HIPAA compliant. Patients undergoing CT for routine indications were enrolled from a random next-available scheduling template by an on-site clinical trials monitor. All subjects received a questionnaire asking them to indicate any DAR occurring later than 1 hour after their examination.
Sixteen manifestations were listed and included rash, skin redness, skin swelling, nausea, vomiting, and dizziness, among others. To ensure maximal surveillance, a clinical trials coordinator initiated direct telephone contact for further assessment. Patients suspected of having moderately severe cutaneous reactions were invited to return for a complete dermatologic clinical assessment including skin biopsy, if indicated.
Statistical analysis was performed by using a twosided Wilcoxon-Mann-Whitney test, a logistic regression
utilizing a x 2 test to adjust for sex and age, and a two- sided Fisher exact test.
Results: A total of 539 patients (258 receiving iohexol and 281 not receiving contrast material) were enrolled. DARs were observed in 37 (14.3%) of 258 subjects receiving iohexol and in seven (2.5%) of 281 subjects in the control group ( P , .0001, x 2 test) after adjusting for sex and age. Specifi c manifestations of DARs that were signifi cantly more frequent at contrast-enhanced CT were skin rash ( P = .0311), skin redness ( P = .0055), skin swelling ( P = .0117), and headache ( P = .0246). DARs involving the skin included generalized
rashes of the face, neck, chest, back, and extremities and were often associated with swelling, erythema, and pruritus.
Conclusion: This study substantiates a frequent occurrence of DARs at contrast-enhanced CT compared with that in control subjects. Continued growth in the use of contrast-enhanced CT suggests a need for greater awareness and attention to prevention and management.
q RSNA, 2010
Supplemental material: http://radiology.rsna.org/lookup
/suppl/doi:10.1148/radiol.10091848/-/DC1


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