Author: Don Stader, MD
- Recent meta-analysis has demonstrated that there is no significant risk for kidney injury from CT contrast
- Most kidney injury seen after contrast CTs were due to other underlying illnesses (sepsis, hypovolemia, etc.)
- Older contrast agents likely did have nephrotoxic effects but this appears to be a thing of the past
Aycock RD, Westafer LM, Boxen JL, Majlesi N, Schoenfeld EM, Bannuru RR. Acute Kidney Injury After Computed Tomography: A Meta-analysis. Ann Emerg Med. 2018 Jan;71(1):44-53.e4. doi: 10.1016/j.annemergmed.2017.06.041. Epub 2017 Aug 12. Review. PubMed PMID: 28811122.
Summarized by Travis Barlock, MS4 | Edited by Erik Verzemnieks, MD
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Author: Sam Killian, MD
- MRI machines can generate enough heat from the radiofrequency to cause thermal burns
- Patients with EKG stickers, medication patches, clothing impregnated with metallic ions, etc., can all increase risk of burns
- Even skin-to-skin contact within the patient can cause a misinterpretation from the software and increased energy, leading to burn
Cross NM, Hoff MN, Kanal KM. Avoiding MRI-Related Accidents: A Practical Approach to Implementing MR Safety. J Am Coll Radiol. 2018 Aug 24. pii: S1546-1440(18)30762-2. doi: 10.1016/j.jacr.2018.06.022. [Epub ahead of print] PubMed PMID: 30149951.
Takahashi T, Fujimoto N, Hamada Y, Tezuka N, Tanaka T. MRI-related thermal injury due to skin-to-skin contact. Eur J Dermatol. 2016 Jun 1;26(3):296-8. doi: 10.1684/ejd.2016.2740. PubMed PMID: 26987101.
Pietryga JA, Fonder MA, Rogg JM, North DL, Bercovitch LG. Invisible metallic microfiber in clothing presents unrecognized MRI risk for cutaneous burn. AJNR Am J Neuroradiol. 2013 May;34(5):E47-50. doi: 10.3174/ajnr.A2827. Epub 2011 Dec 15. PubMed PMID: 22173750.
Dempsey MF, Condon B. Thermal injuries associated with MRI. Clin Radiol. 2001 Jun;56(6):457-65. Review. PubMed PMID: 11428795.
Author: Chris Holmes, M.D.
- The nexus chest CT scan rule is based on an 11,000 subject, multicenter study that looked for signs following a trauma that predicted significant findings on subsequent chest CT.
- Findings that were associated with abnormal chest CT included: abnormal CXR, distracting injury, chest wall, sternal, thoracic spine or scapular tenderness. Furthermore, a mechanism of injury that includes rapid deceleration was also associated.
- If a patient has none of the above findings, then there is only a small chance that there will be an abnormal chest CT.
Author: Dylan Luyten, M.D.
- Around 30% of patients in the ER receive CT imaging, and the sensitivity of CT imaging may be improved with IV contrast. However, contrast is often withheld for fear of contrast-induced nephropathy.
- A recent, single-center, retrospective cohort study compared the rates of nephropathy between contrast CT, non-contrast CT, and no CT control patients, and found no differences.
- This study confirms what many have believed to be true – that the dangers of modern contrast may be overstated. However, the results should be interpreted with caution, as this was a retrospective, single-center study.
References: Hinson, Jeremiah S. et al.. Risk of Acute Kidney Injury After Intravenous Contrast Media Administration. Annals of Emergency Medicine , Volume 69 , Issue 5 , 577 – 586.e4
Author: Peter Bakes, M.D
- Intracerebral hemorrhage is an intracranial bleed within the brain tissue or ventricles.
- Subarachnoid aneurysm causes about 50% of all ICH.
- Amyloid deposition can lead to ICH in elderly patients.
- Hypertension is another common cause of atraumatic ICH, commonly leading to pontine, cerebellar, or basal ganglial bleeding. Bleeding in other locations is suggestive of a different etiology.
- ICH will often present with depressed mental status, but specifically a patient with a systolic BP > 220 is suggestive of hypertensive ICH.
- CT is the first diagnostic step. CTA should be considered when the bleeding is in an atypical area. Significant edema on imaging can be suggestive of a tumor.
- Treatment should include hemostatic measures and BP control. Transfuse platelets if necessary and reverse any anticoagulation. BP target is <140 systolic. Monitor ICP if patient has AMS. Neurosurgical intervention is indicated when there is significant expansion of the hematoma with AMS or if the bleed is cerebellar.
References: Sahni R, Weinberger J. Management of intracerebral hemorrhage. Vascular Health and Risk Management. 2007;3(5):701-709. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2291314/
Run Time: 2 minutes
Author: Aaron Lessen M.D.
- Regularly a patient’s creatinine level is an important factor in determining whether a patient will receive IV contrast with a CT because it is thought that contrast can harm the kidneys and could worsen underlying kidney disease.
- A recent retrospective study compared the rates of worsening kidney problems between patients who received a CT scan with contrast, a CT without contrast, and no CT.
- The study even included patients with creatinines of up to 4 before excluding patients.
- The study suggested that there is no difference in the rate of worsening kidney problems between the three groups.
Run Time: 3 minutes
Author: Jared Scott M.D.
- Pregnancy is a hypercoagulable state and often PE is a concern. When we work up PE in pregnancy the main consideration for harm to the fetus is radiation exposure.
- The amount of radiation to cause harm to the fetus during pregnancy is thought to be 0.1 Gray.
- If 0.1 Gray is the same as $100 of radiation then an X-ray = 1/10 of a penny of radiation, a CT PE scan = 25-50 cents of radiation, a VQ scan = 50-75 cents of radiation, and background radiation during the full pregnancy = $5 of radiation.
- It has been shown that the amount of radiation needed to increase the risk of cancer before age 20 by 1/100 = $10 of radiation – or many, many CT’s and imaging studies.
- CT scans irradiate both the breast tissue and the thyroid of females, which increases the lifetime risk of breast cancer by 1.5%, which is not an insignificant amount.
- The VQ scan is the ideal test for PE during pregnancy, but the downside to a VQ scan is that the radioisotope collects in the bladder directly over uterus before it is urinated out, therefore it is not recommended in the first trimester.
Link to Podcast: http://medicalminute.madewithopinion.com/pregnancy-and-radiation/