Kyung J Cho

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.