#ivcontrast

[teachingrounds]

Q: What is the mechanism by which IV contrast agents create contrast?

A: It’s unique for each modality, as follows:

CT: Iodine atoms absorb x-rays, making tissues appear denser (brighter). MRI: Chelated gadolinium, with 8 unpaired electrons is highly paramagnetic, causing T1 shortening, leading to increased signal in T1-weighted images. Ultrasound: Microscopic bubbles scatter sound waves, making tissues appear hyperechoic.

[teachingrounds]

What imaging studies should be ordered with IV contrast?

For CT and MR, the well-known VINDICATE mnemonic can guide you: Studies to assess for Vascular, infectious, neoplastic, autoimmune, and endocrine/metabolic disorders are usually performed with contrast (except CT for pneumonia). Studies for degenerative and/or traumatic injuries are usually without contrast (except trauma “pan scans” or similar studies). Iatrogenic and congenital can go either way.

Contrast-enhance ultrasound can assess liver and kidney lesions but should be ordered in consultation with a radiologist.

When in doubt, consult the ACR appropriateness criteria or a local radiologist.

[teachingrounds]

American College of Radiology no longer recommends interruption of breastfeeding after IV contrast administration.

Less than 0.01% of intervascular dose of iodinated contrast and less than 0.0004% of Gd-based contrast is absorbed from the GI tract of the child, far less than the permissible dose of IV contrast in neonates. Theoretical risks to the child are direct toxicity and allergic sensitization or reaction, but these have not been reported.  

Read more about this and anything else you want to know about contrast in the ACR Contrast Manual, a regularly updated, evidence-based consensus statement. For the remainder of the week, we’ll summarize topics discussed in the Manual.

[lumber]

I ♥️ the smell of #IVContrast in the morning. Had another #CatScan early this morning- this time of the head and neck areas. Last week's was of my brain. #Fun! 🙄 #Northridge #NorthridgeDiagnostic #ImagingCenter #FelixTheCat #FelixTheCatScan #CatScanWithContrast #CatScanWithDye (at Northridge Diagnostic Imaging Center) https://www.instagram.com/p/CDegzW4DR4S/?igshid=1nxiqhp5semr6