Kyung J Cho, William Martel Professor, Department of Radiology, Vascular/Interventional Radiology, University of Michigan Health Systems, USA, was awarded the 2012 SIR Gold Medal along with Dimitrios Kelekis and Louis Martin. He tells Interventional News about his journey in interventional radiology…
How did you come to choose medicine? What drew you to interventional radiology?
My aspiration to become a doctor was partly due to my cousin who was a medical doctor.
My decision to choose a career in medicine was an easy one as I knew I wanted to care for sick people. My experience as a military physician is significant and perhaps has paved the way for me to become an interventional radiologist. After graduating from the Catholic Medical College, I joined the Republic of Korea Air Force as a military doctor and ROK Air Force officer. I was assigned to the Bengyeon Island Air Force Base off the coast of North Korea. During that time, I had to deliver a baby in the breech position. C-section was not an option as no obstetrician or gynaecologist was available. The baby was finally delivered but the placenta did not detach, resulting in continuous bleeding. I transfused the mother with one unit of my own blood in order to maintain stable blood pressure until she could be transferred to the Korean Air Force Hospital in Seoul.
In 1975, I observed Dr Stewart Reuter in a procedure as he placed a catheter in the left gastric artery in order to stop a gastric haemorrhage with embolization. I was amazed by how he did it with a catheter. It was then I decided to pursue an academic career in interventional radiology.
Which innovations in interventional radiology have shaped your career?
First, I would like to mention the technique for percutaneous catheterisation devised by Seldinger in 1953, which led to the evolution of interventional radiology.
In 1964, Dr Charles Dotter introduced percutaneous transluminal angioplasty for treating peripheral arteriosclerotic occlusive lesions without operation. With the availability of angioplasty balloon catheters, it became the basic technique commonly used for percutaneous treatment of luminal narrowing of both the vascular and nonvascular systems. Additionally, the evolution of catheterisation equipment, particularly torque control wires and microcatheters, has made superselective catheterisation in almost any region of the body possible. With superselective angiography and the availability of a variety of occlusive agents (liquid, particulate and mechanical) transcatheter embolic therapy has become the preferred treatment for control of bleeding, palliation of tumours, and ablation of vascular lesions.
Many other innovations that have contributed to shaping my later career include arterial interventions, venous interventions, stenting, catheter-directed thrombolysis, pharmacomechanical thrombectomy, vena cava filters, abscess drainage and hepatic oncologic intervention.
Who were your mentors in interventional radiology?
My first mentor was Stewart Reuter, who I met at the Wayne County General Hospital, Wayne, Michigan. Stew was a great mentor and role model not only in my career but also in my personal life. He shared his knowledge of teaching me how to perform angiography. He also taught me how to write and speak in English. He was a brilliant yet kind and compassionate man. He loved any kind of research that was related to diagnostic angiography and interventional radiology. I would not be where I am today had I not met him. In 1980, I spent a six-month sabbatical leave at the University of Lund, Sweden where I met Dr Anders Lunderquist. He was widely recognised as a pioneer in interventional radiology. He was a great man who loved interventional radiology. Anders was interested in basic science research which he continued after he retired. I spent many hours with him, studying hepatic microcirculation of the rabbit liver cast under dissection microscopy. He emphasised the importance of hands-on training for acquiring technical skills and discipline in performing procedures to prevent complications. Later, I spent my second sabbatical with Dr Irvin Hawkins at University of Florida, Gainesville, Florida. He was widely recognised as a pioneer in interventional radiology. As an innovator, he was always thinking of ways to improve devices and techniques to minimise complications. Until his passing in June 2011, he continued to talk about how to improve central venous catheters to prevent catheter-related venous stenosis and also the method to secure central venous catheters in place and improve the CO2 DSA technique. His research about CO2 as an alternative contrast agent spanning over four decades is impressive and made a huge impact on the way angiography and endovascular procedure are performed. When he had an idea about interventional radiology devices or technique, he got up from his bed and went to his desk to work. I miss him very much. My other mentors are Dr Vincent Chuang and Dr Joseph Bookstein who helped me in my career and research. They both are great interventional radiologists with a passion for new findings in diagnostic angiography, basic science and the development of new techniques. I have been fortunate to have had such great mentors throughout my career.
Tell us about an early moment in your career when you were amazed by what the specialty could achieve…
A neonate was referred to interventional radiology who had congestive heart failure and thrombocytopenia as complications of an inoperable haemangioma of the pelvis. Selective gelfoam embolization of the internal iliac artery feeding the haemangioma through the umbilical artery combined with steroid treatment achieved significant diminution in her congestive heart failure resulting in a rapid and complete resolution of this life-threatening problem.
What are the three most important things you focus on as a teacher of interventional radiology?
First, I must understand the goals and objectives of interventional radiology training which include providing the trainee an organised, comprehensive education, performance of procedures, learning clinical management of patients, and skills for research. Second, I want to demonstrate core values which are respect and compassion, collaboration, innovation and commitment to excellence. Third, I want to encourage and praise the strengths of the trainees while helping correct their weaknesses. The trainees are the future of our next generation and they should be taught with our core values to help them to advance medicine and interventional radiology and serve humanity. I want to be a role model for the trainees. I want to help, teach, lead and give my time whenever they need it. I go to work happily and smile and encourage the trainee with enthusiasm in whatever they do. I also show them punctuality and go to work early in the morning to participate in interventional radiology inpatient rounds.
What have been the three most interesting findings from your research so far?
I studied the hepatic microcirculation in collaboration with Dr Anders Lunderquist. In this study, silicone rubber solution of various colors (Microfil) was injected into the hepatic artery (orange), the portal vein (yellow), and into the bile duct or hepatic vein (white) in rabbits. Then the liver specimen underwent the tissue clearing process with increased concentrations of ethanol and was examined in methylsalicylate solution under a dissection microscope. The most intriguing findings from those liver casts were as follows. The hepatic lobule is not a structural unit with identifiable boundaries. Rather it is composed of continuous one-cell thick plates which are tunneled by labyrinthin lacunae of sinusoids. The lobular sinusoids are three-dimensional continuously anastomotic network through which the portal and hepatic venous branches interdigitate with each other. The peribiliary vascular plexus was a profusely, rich anastomotic vascular network existing in the wall of and around the bile duct. The plexus consists of two distinctive layers; the inner capillary and the outer venous plexus. Arterioportal communications exist at the presinusoidal arterioportal venular connection, the peribiliary plexus and through the vasa vasora of the portal vein.
Vena cava filters of two different designs, conical and non-conical were evaluated in sheep with cavography, intravascular ultrasound and histopathology. At 60 days after filter placement the filter with the nonconical design showed slow resolution of the trapped clot and extensive fibrin webbing that encompassed more than half of the caval lumen and occlusion of filter strut spaces. In contrast, the filter with the conical design such as Greenfield filters showed a smooth caval luminal surface without any fibrin webbing. The hooks were well incorporated within the caval wall.
I studied the safety and efficacy of CO2 as an intravascular contrast agent in both swine and humans. Intravenous injections of CO2 in diagnostic volumes of up to 60cc are safe without any vital sign changes. Swine can tolerate large volumes of intracaval CO2 injections at the doses of up to 6.4cc/kg body weight.
What are your current areas of research?
One of my current areas of research is the use of carbon dioxide as a contrast agent for visualisation of blood vessels for diagnosis and endovascular procedure, and a safe gas delivery method without air contamination. Conventional contrast materials containing iodine can be toxic to the kidney when its function is poor and may cause allergic reaction. However CO2 is a natural bi-product and therefore, has no chance to injure the kidneys and cause allergic reaction when administered into the vascular system. CO2 is a proven safe contrast agent in patients with compromised renal function and a history of allergic reaction to iodinated contrast material. It often provides additional diagnostic information and in some areas the gas is superior to iodinated contrast medium. CO2 should not be used in the thoracic aorta, coronary and cerebral circulation.
What are your views on how complications are currently measured in interventional radiology?
Documentation and review of procedure-related and outcome complications are important in improving patient care quality. There has been no standardisation of measurement of complications in interventional radiology. I believe that a comorbidity-adjusted complications risk should be incorporated in the current system provided by the SIR Standards of Practice Committee since more and more complex and high-risk patients are being referred to interventional radiology. The SIR Standards of Practice Committee have published a number of quality improvement guidelines for specific interventional radiologic procedures. Overall the documents are excellent and should be used for the VIR fellowship training and quality assurance programme.
If you had a wish-list on three areas you could improve in interventional radiology, what would they be?
I believe that interventional radiology is a victim of its own success. Interventional radiology practice and healthcare delivery, and the education of its trainees will need to be redefined for the future of interventional radiology. It is known that our procedures are safer and effective, benefitting both patients and interventional radiologists. Before considering a wish-list I want to briefly discuss the challenges that interventional radiology faces. The two main challenges are migration of endovascular procedures to other disciplines and often insufficient support from the academic departments and healthcare leadership while the number and variety of vascular and nonvascular interventional procedures have increased. Furthermore, the complexity of the cases performed in interventional radiology has significantly increased, often requiring intervention and hospital admission after hours. In brief, interventional radiology practice requires performance of interventional procedures, writing pre- and post-procedure notes, generation of procedure reports, admission, inpatient ward rounds, clinic follow-up, and outpatient clinic. Interventional radiologists have many other responsibilities including teaching, research, and participation in the local, regional and national committees.
Here is my wish-list: first, interventional radiology practice needs strong support from the healthcare leadership and radiology department chair with regard to equipment, space and support staff. Second, once adequate support staff is available, we should expand both interventional radiology inpatient and outpatient practice. Third, I strongly believe that in the cardiovascular centre setting, fragmentation of academic medicine should be avoided and multidisciplinary, coordinated patient care practice should be instituted. The healthcare leadership must promote a team concept and creation of multidisciplinary collaboration to achieve compassionate interventional radiology clinical practice and excellence in education and research.
In summary, interventional radiologists may face significant challenges in their practice in the coming years. Many interventional radiologists will suffer from inadequate support from their own radiology departments and healthcare leadership. Interventional radiology will witness continuous migration of endovascular procedures as vascular surgeons, cardiothoracic surgeons, and interventional cardiologists continue to expand their endovascular practices. Since interventional radiology is involved in the healthcare business, it must be prepared to provide comprehensive patient care.
What are your interests outside of medicine?
Outside of medicine I enjoy spending time with my wife Young and our three children, Cathy, David and James. My interests include playing the violin, tennis, racketball, gardening and golf. I try to practise the violin every day. Golf is interesting, challenging and also rewarding, like my profession.
1960–66 Catholic University, Medical School, Seoul, Korea, MD
1982 Professor, Radiology University of Michigan Medical School
1997–present Director, Radiology Animal Imaging Lab, University of Michigan, Medical School
2005–present Consulting physician, VA Medical Center, Ann Arbor
1989–1992 Consultant to editor, Journal of Interventional Radiology
1990–2001 Consultant to editor, Journal of Cardiovascular and Interventional Radiology
2001–present Managing editor, Emedicine, Interventional Radiology
1980–present Reviewer, American Journal of Roentgenology
1991–2000 Reviewer, Journal of Vascular Surgery
1992–2001 Reviewer, Journal of Cardiovascular and Interventional Radiology
1990–present Reviewer, Journal of Vascular and Interventional Radiology
2002–present Chief editor, eMedicine, Interventional Radiology
2005–2008 Assistant editor, American Journal of Roentgenology
Selected honours and awards
1982 Award for Outstanding Teaching of Radiology Residents University of Michigan Hospitals
2003 Lifetime Achievement Award in Medical Education, University of Michigan Medical School
1999 William Martel Collegiate Professor of Radiology (Endowed Professorship)
University of Michigan Medical School
July 2000 Distinguished professor of Radiology, Department of Radiology, The Catholic University, Seoul, Korea
2011 JVIR Editor’s Award for Distinguished Reviewer
Selected membership in professional societies
- American College of Radiology
- American Medical Association
- American Roentgen Ray Society
- Radiological Society of North America
- Society of SIR, fellow
- Society of Gastrointestinal Radiology
- Fellow of American College of Radiology
- Advisor, the Vascular and Interventional Radiology Foundation, Hong Kong