For this Power Pack, we are trying out a new interactive case solution that we are testing to see if it provides a richer and more impactful learning experience. The content of this course is exactly the same as our original Knee Power Pack course. Please be sure to answer the survey at the end of the course to help us gather feedback.
The user will gain experience detecting strokes on CT by reviewing the 30 cases of subtle stroke presented in this module. The purpose is NOT to comprehensively explain the role of imaging in the evaluation of acute stroke or to teach a junior physician how to approach a CT scan of the brain. Rather, it is hoped that by reviewing these difficult cases the reader will become better at detecting the subtle CT findings of acute stroke. Some of these cases were initially interpreted correctly. Many were not.
Some may say that stroke is a clinical diagnosis and that role of non-contrast CT is to exclude hemorrhage so that treatment can commence. This may be true given the increased availability of CTA, CT perfusion, and MRI perfusion. So why look at difficult cases? It is still nice to be able to make the diagnosis of stroke on CT when the findings are present. Not only does this make you look and feel good, but there will be times when stroke is NOT being considered clinically (for example with clinical histories of confusion or altered mental status or in young patients with suspected severe migraines), and making the diagnosis could radically alter the treatment. In addition, identifying the subtle changes in acute stroke is necessary for grading early stroke severity (such as creating an ASPECTS score) which can affect treatment options.
Each case contains a non-contrast CT scan and either a follow-up CT or MRI. Review the initial exam and try to find the infarct. Then look at the follow-up exams to see if you were correct. After answering a quiz question you are presented with a short didactic that interactively links to images in the study. The didactic begins with a sample report followed by a discussion of the original scan, a discussion of the follow-up scans, and specific teaching points relevant to the case usually related to the quiz question. Read as much or as little as you want. For some users, simply viewing the follow-up scans will be enough. Less experienced readers may benefit from the entire didactic. Quiz question answers are at the bottom of the write-ups.
I hope you enjoy looking at these challenging cases more than I did interpreting them in the real world.
John Ryu, MD
Neuroradiology Fellow at Penn