Low osmolality contrast medium is considered medically necessary in patients with high risk of severe reactions to conventional agents. The following are recognized as risk factors:
1. Kidney factors
a. Renal failure (serum creatinine greater than 1.5mg / dl)
2. Multiple myeloma
3. Cardiovascular factors
a. Under 1-year-old
b. Unstable angina.
c.Congestive heart failure (Class IV of the American Heart Association of New York)
d. Recurrent ventricular tachycardia and an ejection fraction below 0.30
e. Severe pulmonary hypertension (systolic over 70 mm / Hg)
f. Cardiogenic shock or other hemodynamic instability
g. Period within 6 months after myocardial infarction complicated with hypotension.
h. Stenosis of the main left coronary artery, greater than 50%
i. Symptomatic severe aortic stenosis
j. Septal ventricular defect
4. Allergy to conventional contrast:
a. Where no other imaging modality can be offered
The dose of contrast is not absolute. In large and complex areas, a large volume of dye is required for an accurate diagnosis.
Example: Computerized tomography
1. Use of a single dose head, ear, eye orbit, renal, pelvic (prostate, ovaries, etc.)
2. Use of two doses: neck (submandibular parathyroid glands), chest, abdominals (liver, pancreas).
