The nutcracker phenomenon (NCP) is an accentuated phenomenon of normal subtle compression of the left renal vein (LRV) between the abdominal aorta and superior mesenteric artery. The nutcracker syndrome (NCS) is a syndrome caused by NCP, resulting in hematuria, proteinuria, or left flank pain.
The established diagnostic criterion of NCP is a pressure gradient more than 3 mmHG across the compression site, and NCS has been known to be rare, but probably is not rare and in fact quite common. The most important reason why NCS is known to be rare is that the diagnosis is difficult unless invasive venous catheterization and pressure measurement confirm the pressure gradient. Doppler ultrasound is useful in measuring the flow velocity of LRV. From the velocity measured by Doppler ultrasound, we may estimate the pressure gradient. Doppler ultrasound of LRV needs technical skills and experience. Computed tomography (CT) is a popular imaging technique for patients with hematuria, and we need to be familiar with the findings of the NCP at CT. There are variations of NCP associated with vascular anatomy and posture of the patients. This book will illustrate the concepts of NCP and NCS, findings at Doppler ultrasound and CT, and variations of NCP.
About the Author: Seung Hyup Kim, M.D., Ph.D., is currently Professor Emeritus of Radiology and Urology at Seoul National University College of Medicine, Seoul, Korea.
Dr. Kim received his M.D. in 1979, his master's degree in 1982, and his Ph.D. in 1988 at Seoul National University (SNU). He completed his internship and residency at the Seoul National University Hospital (SNUH) and became a board-certified radiologist in 1983. After his military service, he became an instructor in radiology at the SNU in 1987, spent one year as a visiting radiologist at the Hospital of the University of Pennsylvania, and advanced through the academic standings to become a professor of radiology, a professor of urology, and Associate Dean of SNU (2002-2004). Dr. Kim served as the Chair of the Department of Radiology for 2 years (2008-2010) and Vice President of the SNUH for 3 years (2010-2013).
Dr. Kim was the Secretary General of the 11th Congress of the World Federation for Ultrasound in Medicine and Biology (WFUMB 2006 Seoul). He was one of the key members in upgrading the Korean Society of Ultrasound in Medicine (KSUM) and transforming the KSUM annual congress to an international one with the slogan of "KSUM Open," adopting English as the language of the congress. From the year 2001, he contributed to the Asian Federation of Societies for Ultrasound in Medicine and Biology (AFSUMB) as a council member, treasurer, secretary, and president (2012-2014). In WFUMB, he has contributed as a councilor, vice president, and chair and as a member of various committees. From September 2019 to May 2021, he served as the President of WFUMB
The main subspecialty of Dr. Kim is urogenital imaging and intervention, and he has 401 publications and 11 monographs to his credit. His main works are Radiology Illustrated: Uroradiology and Radiology Illustrated: Gynecologic Imaging.
