L5-S1 spondylolisthesis causes bilateral L5 radiculopathy from anterior vertebral slip. Inverted Napoleon Hat Sign on AP radiograph shows trapezoidal L5 atop S1 in high-grade cases, graded by Meyerding system.
Radiology Case of the Day 98
| Radiology Case of the Day | By
Dr. Amar Udare, MD
| Last Updated On: March 7, 2026 | 4 minutes of reading
About The Author
Dr. Amar Udare, MD
Dr. Amar Udare is a board-certified radiologist (MD,DNB) with over 10 years of experience and a special interest in body imaging. He currently serves as a Clinical Associate Professor in Diagnostic Imaging (Radiology) at the University of Calgary . With a passion for teaching, he has been a semi-finalist for the Aunt-Minnie Most effective Radiology Educator Awards in 2018 and 2020.
Dr. Udare holds an MBBS and MD degree, and his expertise lies in the field of radiology. He has authored multiple peer-reviewed publications, contributing significantly to the medical field. His works can be accessed on PubMed and Google Scholar.
In addition to his academic and professional achievements, Dr. Udare is an avid reader and enjoys exploring the latest advancements in medical technology. His commitment to making complex medical knowledge accessible to patients and the general public aligns with our mission at RadioGyan.com.
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