The Radiology Review Podcast Erratum
From Dr. Covington: I double-check facts that I am unsure about and try my best to cross-check content prior to recording and releasing episodes, speak accurately on my podcast, and type correctly for written materials I produce. In certain cases I have and will likely continue to make errors. When I discover these errors I will list them here. I will also try my best to correct errors on study guides.
It is technically challenging and time consuming to fix recorded audio errors on episodes of my podcast that have been released. I therefore have created this page on my website so listeners can find the errors that I am aware of that exist in my podcast episodes and learn from my mistakes. If you have noticed an error in something I have recorded or written please let me know at theradiologyreview@gmail.com or on Twitter or Instagram @radrevpodcast.
Nuclear Medicine: HIDA Scans for the ABR Core Exam Part 2
At 3 minutes and 35 seconds Dr. Covington incorrectly states “VQ Scan” instead of “HIDA scan”. The question was read as “After how many minutes is morphine typically administered for a VQ scan?”. The question should have been read: “After how many minutes is morphine typically administered for a HIDA scan?” This question was correctly presented on the corresponding study guide for this episode.
Ultrasound Physics and Artifacts
From a listener: “I was listening to your episode on ultrasound physics this morning on my drive to work and I think I may have found an error. I believe you said that the speed of sound in tissue increases with increasing tissue density. The speed of sound in any substance is related to both the bulk modulus (K) and density (p), and is:
c = sqrt(K/p)
Across substances, K tends to increase much more than p so generally speaking I think what you said holds true - metal is perfect example of this.”
Head and Neck Masses Part 2
The episode and study guide stated the Wharton’s duct is associated with the sublingual gland. This is incorrect. Wharton’s duct is associated with the SUBMANDIBULAR gland. The study guide has been corrected.
CNS Tumors Episode 2
The question “What is more common in the spine—medulloblastoma or ependymoma?” contains an incorrect answer “Medulloblastoma is much more common than ependymoma.”
Approximately 350 cases of medulloblastoma are diagnosed annually compared to approximately 1300 cases of ependymoma per year. About 10% of ependymomas are found in the spinal cord compared to up to 33% of medulloblastomas involving the leptomeninges of the spinal cord. Therefore, involvement of the spinal cord is likely more common in ependymoma.
VQ Scans Episode 1
At the 22:20 mark for the question about the significance of a perfusion scan with hepatic caudate lobe uptake, the answer is erroneously stated to be SVC occlusion. This is incorrect. Caudate lobe uptake is characteristic for Budd-Chiari/hepatic vein occlusion whereas quadrate lobe uptake is characteristic for SVC obstruction, though also reported for IVC obstruction. Thank you to the listener who pointed out this mistake!
The VQ Scan study guide has been updated to now read:
Perfusion scan with hepatic caudate lobe uptake? **Note that the episode states SVC occlusion but this is a mistake** The correct answer is Budd-Chiari with hepatic vein obstruction. Superior vena cava occlusion is classically associated with quadrate lobe uptake, and there are some reports of inferior vena cava obstruction also causing quadrate lobe uptake. See article here: doi: 10.4103/0972-3919.178325
Hot caudate lobe: Budd-Chiari
Hot quadrate lobe: SVC and/or IVC obstruction
VQ Scans Episode 2
At about 17:40, the question is asked what the probability of PE is if there is an entire lung mismatched perfusion defect. The answer I stated was “high probability”. This is, in fact, questionable.
Although PE is possible in this setting (large central), it is unlikely. If PE were present, and is central, you would also typically expect defects in the other lung. See a great review of this here.
The answer is vague and I am trying to sort this out (some sources say low prob, others say that given this is 2+ large, mismatched defects it is high prob). Given that this is vague, I doubt this would be tested in terms of forcing you to assign a probability, but rather may probe for differential considerations. If you see this absent perfusion of an entire lung with normal ventilation, it is a definite good idea to correlate with radiographs or preferably chest CT to see what is causing the central compression on pulmonary blood flow—be it cancer or otherwise.
Also, see discussion here.
Mammo Quality Control Episode
For the question: How many of each of these (fibers, speck groups, and mases) must be visualized in order to pass the breast phantom test?
The answer was stated: You must be able to see at least 4/6 fibers, 3/5 speck groups, and 3/5 masses on the phantom test to pass
Although possibly not technically an error, there are updated ACR phantoms that no longer follow the classic 4-3-3 rule, but follow a 2-3-2 rule. More info here: https://accreditationsupport.acr.org/support/solutions/articles/11000065938-phantom-testing-mammography-revised-12-12-19-
“For the small ACR Mammography Phantom, in order to pass there must be no clinically significant artifacts and the 4 largest fibers, the 3 largest speck groups, and the 3 largest masses must be visualized.”
“For the ACR Digital Mammography Phantom, ACR phantom image reviewers will follow the same process outlined in the 2018 ACR Digital Mammography Quality Control Manual. Medical physicists and quality control technologists should follow the same procedures as part of their routine QC. In order to pass there must be no clinically significant artifacts and the 2 largest fibers, the 3 largest speck groups, and the 2 largest masses must be visualized.”
Thank you to the listener who pointed out this important issue.