Radiology in the Lion City

Introduction

After receiving my medical education and practicing radiology in the United States for more than 4 decades, I was given the opportunity to serve as a visiting professor at the National University of Singapore in late 2014. The position allowed me to refamiliarize myself with Asian culture, witness some different patterns of disease, and experience the effect of local health policy on the practice of medicine and radiology. Because the United States continues to be a melting pot, physicians must be aware of and sensitive to the cultural differences among various ethnic groups. For radiologists, it is equally important for us to be cognizant of variants of imaging findings in these patients so that we will not be overly zealous in recommending extensive evaluations.

Background Information

The Republic of Singapore is an island nation in Southeast Asia. Approximately 5.4 million people live in Singapore, of which 70% are citizens and permanent residents, while the remaining are foreign workers or students and their dependents. Singapore has a diverse ethnic population of Chinese (75%), Malay (13%), Indian (9%), and Eurasian (more than 3%) people. According to Pew Research (1), one-third of the population practice Buddhism, with the rest divided among Christianity, atheism, Islam, Taoism, and Hinduism. More than 80% of the population has at least a primary school education.

Singapore is blessed with an amazing variety of food, ranging from typical Western fast food to the diverse ethnic delights and fine dining of various countries. At the National University Hospitals, there are dozens of small restaurants, plus two large food courts housing numerous stalls offering different ethnic foods, desserts, pastries, and fruits. Although many food stalls offer cooked vegetables, Western salad is not as easy to find. Although I used to eat a simple fresh mixed salad for lunch in Chapel Hill, NC, I succumbed to local delicacies consisting largely of noodles, meat, and cooked vegetables. It is not difficult to see how one can easily gain weight if it were not for the fact that Singaporeans are constantly reminded to exercise. Nevertheless, hyperlipidemia, hypertension, and diabetes have become common diseases. The Economist ranked Singapore as having the best quality of life in Asia and as 11th overall in the world in 2005 (2).

Health Care

Singapore has an efficient health care system that ensures affordability through a system of compulsory saving, subsidies, and price controls. It uses general practitioners as gatekeepers for access to specialists and discourages overuse with a copayment scheme. The World Health Organization ranked the Singapore health care system as sixth overall in the world in the year 2000, and Bloomberg Business ranked it as the most efficient in the world in 2014 (3,4). The country has had the lowest infant mortality rate in the world for the past 2 decades (5). Life expectancy in Singapore is 80 years for men and 85 years for women, placing the country fourth in the world for life expectancy. The physician-to-population ratio is 19.2 per 10 000 in Singapore compared with 24.2 in the United States (6).

The system has three tiers of protection: Medisave, Medishield, and Medifund (7). Medisave, a compulsory health savings account, is required for all citizens and permanent residents of Singapore who contribute part of their wages to their individual account. In addition, unless individuals choose not to, they are automatically enrolled to purchase Medishield, government-sponsored, low-cost, catastrophic medical insurance that allows Singaporeans collectively to pool the financial risks of major illnesses. Individuals who enroll in Medishield can further supplement their health benefits (eg, better hospital room or choice of private hospitals) by buying an integrated shield plan from private insurers. Medifund provides an ultimate safety net for those not able to afford medical bills even with heavily subsidized Medisave and Medishield.

Approximately 80% of Singaporeans receive their medical care within the public health system. In 2012, there were a total of eight public and seven private hospitals and six specialty centers in Singapore. The eight public hospitals include six acute care general hospitals, one women’s and childrens’ hospital, and one psychiatric hospital (7). The private sector provides care to those who are privately insured, foreign patients, and public patients who are willing to pay very large out-of-pocket costs. Many private insurance policies with various premiums and coverage are available to the foreigners. However, awareness of insurance policies for physician visits is important lest reimbursement requests be denied. Specifically, most policies in Singapore require referral from a general practitioner before access to a specialist, a policy of which I was not aware and which would not have been required in the United States, before I visited a local ophthalmologist for an eyelid infection recently. Although use of the general practitioners as gatekeepers is designed to lower health care costs by reducing unnecessary visits to specialists, policy holders like me may view such a practice as unnecessarily onerous and not user friendly.

Radiology Training and Practice

Training and certification of specialists in Singapore are governed by two separate and independent bodies similar to the Accreditation Council for Graduate Medical Education and the American Board of Medical Specialties in the United States (8). There are three training programs with a total of 24 approved resident positions per year. Traditionally, radiology training programs have been modeled after those of the Royal College of Radiology in the United Kingdom, with trainees entering a radiology residency program after 5 years of medical school and 1 year of mandatory housemanship (clinical internship). This approach to radiology training consists of two stages: basic specialist training (1 year of clinical medicine and 3 years of diagnostic radiology) and advanced specialist training (2 more years of diagnostic radiology). Trainees who have successfully completed the training and passed all the specialty examinations (Fellow of the Royal College of Radiologists examination in the United Kingdom, part I and Parts IIA and IIB) are eligible to register as a specialist (ie, consultant) with the Singapore Medical Council. A substantial percentage of young consultants also go overseas (the United States or the United Kingdom) for 6–12 months of fellowship training. Registered specialists must obtain a minimum of 50 continuing medical education points every 2 years to maintain their license; no recertification examination for diagnostic radiology is planned. In 2013, a total of 258 radiologists were registered with the Singapore Medical Council.

Since 2010, the Ministry of Health in Singapore has worked with the American Accreditation Council for Graduate Medical Education to change the residency training program to be similar to the American system. The American Board of Radiology also has worked with the local radiologists to create an international version of the American Board of Radiology examination, with the first examination scheduled for March 2016. While the British system is similar to an apprenticeship, with emphasis on independent hands-on experience but without minimum requirements for core rotations, the American system is more structured, with mandatory rotation time in each of 10 subspecialties, and places more emphasis on education than service. Although the two systems differ in their style and philosophy of graduate training, both systems are known to be rigorous and to produce equally competent clinical radiologists. It would be interesting to examine whether such a transition in training approach will have any recognizable differences in Singapore.

Radiology residents in Singapore work hard, are smart, and are educated in an environment where orders for imaging studies are scrutinized more stringently for clinical justification. Furthermore, in the old system, residents were required to spend 2 years in clinical medicine after medical school before entering radiology residency program. Therefore, they tend to be more clinically oriented than radiology residents in the United States, where imaging studies are ordered more liberally. Although radiology residents in Singapore work longer days, they are limited to working no more than 80 hours per week. Furthermore, they receive extra compensation for covering nights and weekends. Just as in the United States, residents screen imaging requests, assign protocols, and interact with requesting clinicians (usually residents from other departments) and radiologic technologists (called radiographers). Residents consult well-known Web sites such as STAT-DX and Radiopedia.org for learning, as they do in the United States. Although hierarchy clearly exists in medicine (radiology) in Singapore, as it does in the United States, and although there is more deference to authority and elders in Asian culture, radiology residents in Singapore freely raise questions or provide their sources of information when they disagree with consultants, albeit in a polite and respectful manner.

In academic centers such as the National University Health System, clinical departments are staffed by both hospital-employed consultants (board-certified radiologists) and university-appointed faculty (who are consultants in clinical service and also have an academic rank). The chair of the department is responsible for overseeing both groups, who work together in clinical service, but university-appointed faculty members have an average of 2 days per week allocated to research and teaching. Consultants are well trained and well versed in state-of-the-art technology, and a few of them are involved heavily in clinical research. As in the United States, consultants perform and interpret studies independently and sign off on preliminary interpretations rendered by the trainees during the day. They also review senior residents’ interpretation of night call cases the following morning, provide addenda to the original interpretation if it contains substantial error, and alert the referring physician of the changes. Radiologists in academic centers and large practice groups widely use teleradiology to provide interpretation for studies performed in outlying clinics in the country but not outside the country. In contradistinction to practice in large academic centers in the United States, where subspecialty faculty only practice in their area of expertise, subspecialty consultants in Singapore regularly practice outside their subspecialty training (ie, neuroradiologists perform general radiology, vascular and interventional radiologists rotate through the body imaging section) even in large academic centers. Although I may be regarded as a “renaissance” radiologist in American academic institutions because of my ability to cover all aspects of abdominal imaging (fluoroscopy, computed tomography [CT], magnetic resonance [MR] imaging, and ultrasonography [US] of both gastrointestinal and genitourinary systems) and perform imaging-guided biopsies, I am less versatile than rest of the radiologists in Singapore. Nevertheless, with the help of the picture archiving and communication system, I can easily choose the cases with which I am most comfortable. Partly because of their respect for seniors and partly because of my reputation as an accomplished academic abdominal radiologist, I was accepted quickly in the department, shown interesting cases, and asked to consult on difficult abdominal cases.

Although the department is geographically scattered throughout the medical center, consultants from different sections have more interaction with one another because of routine cross coverage and common reading rooms. The department sponsors a weekly “tea break” (with fruits, various ethnic food, and pastries) each Wednesday morning to facilitate informal interaction among consultants and trainees. Periodic appreciation dinners for trainees and consultants, regular staff meetings, and a yearly department retreat are all designed to foster team work.

In general, imaging requests contain more relevant clinical information or reasons for the study than those seen in the United States. However, disagreements regarding the appropriateness of a requested (ordered) imaging study for a given patient’s clinical condition do occur on a daily basis. Although older clinicians, especially those trained in the British system, still view a request for an imaging study as a request for radiologic consultation, younger clinicians tend to treat an imaging request as an order or a prescription to be filled. This practice, although not condoned by all, is nevertheless widely accepted as the norm in the United States.

Similar to those in Europe and the United States, radiologists in Singapore are concerned and conscientious about the deleterious effect of excessive and unnecessary radiation. Every effort is made to keep the radiation dose as low as possible for diagnostic examinations such as CT. Furthermore, US is used liberally as a screening procedure. However, largely for economic reasons, four-phase CT, in spite of its large radiation dose, is used to detect hepatomas in patients with hepatitis instead of MR imaging.

Influence of Culture and Policy on Disease Presentation and Treatment

In spite of the availability of health coverage and easy access to care in Singapore, patients seem to present with more advanced disease at imaging than I have seen in my 35 years of practice in the United States. To the best of my knowledge, this phenomenon may be more common in Southeast Asia than in Japan or South Korea. For example, I saw one patient with cervical carcinoma who did not seek medical care until the mass was visible externally, and another patient with renal cell carcinoma was referred for an imaging study only after the mass had protruded through the flank. Although such observation may be skewed, several factors might have contributed to this phenomenon.

More judicious use of imaging studies by the clinicians (ie, only when there is a strong clinical suspicion of underlying disease) may partially account for the observed phenomenon, because many diseases cause relatively few symptoms at early stages. This is contrary to the prevailing practice of defensive medicine in the United States, where imaging studies are used liberally to exclude disease, thereby leading to the discovery of early-stage, incidental, yet sometimes clinically important results. In a recent survey (9) of emergency department physicians in the United States, more than 85% of the surveyed physicians believed that too many diagnostic tests were ordered in their own emergency departments, and 97% said that at least some (mean, 22%) of the CT and MR imaging studies they personally ordered were medically unnecessary. The main reasons given were fear of missing a low-probability diagnosis and fear of litigation.

Another equally important factor, if not even more so, may relate to cultural factors such as a fatalistic view of life, self-denial, mistrust of Western medicine as too toxic and too invasive, and wide availability of alternative medicine (eg, Chinese herbs and traditional Malay, and Indian remedies). The latter attitude, prevalent throughout patients of various educational levels and socioeconomic classes, may contribute to delay in seeking medical care and may account for reluctance to accept treatment once the diagnosis is made (10). For example, the incidence of aortic dissection is high, partly because patients who have received a diagnosis of hypertension often stop antihypertensive medication prematurely for fear of long-term adverse effects caused by Western drugs (Lenny Tan, MD, personal communication). Likewise, patients who have received a diagnosis of cancer sometimes refuse treatment or try alternative medicine first because it is perceived to have fewer adverse effects, only to return later when the disease is more advanced and has caused substantial symptoms and discomfort. The fatalistic view of life in some religions coupled with a government-sponsored insurance policy often leads to more rational use of medical resources. Although Singapore has universal health insurance for its citizens, and although the Medisave account can be shared among family members for medical copayments, patients, especially older ones, often do not wish to impose financial hardship on their family members by using family medical savings for terminal situations. Patients and their family members often prefer a peaceful departure from this world rather than insisting on heroic medical intervention when a condition is deemed terminal (eg, leaking mycotic aneurysm in an elderly patient with other comorbidities). Therefore, mechanical ventilation for patients in a vegetative state is not used for a prolonged period of time.

In addition to more judicious use of imaging studies, clinicians and radiologists in Singapore are more cost conscious in the selection of imaging modalities, because reimbursement for both hospitals and physicians is capped according to disease groups rather than volume of activities. Although advanced imaging technologies (eg, MR imaging, positron emission tomography/CT) are widely available, and although radiation from diagnostic tests is of general concern, multiphasic CT is still preferred to MR imaging, even in cases which require serial examinations (eg, screening for hepatocellular carcinoma in patients with known viral hepatitis), largely because of the cost differential for both the insurer (government, private insurance companies) and the insured (patients who are responsible for the copay).

Disease Prevalence and Patterns including Normal Variants

It is well established that certain diseases are more prevalent in Asia. These include hepatomas, nasopharyngeal carcinomas, gastric cancers, and tuberculosis, just to name a few. However, I have observed several abdominal findings on CT studies of which I was not aware during my more than 35 years of practice in the United States and that, to my knowledge, have not been reported in the medical literature. Although radiologists in Singapore are fully cognizant of these findings, they are not aware of the differences between the two populations. Likewise, informal survey of my colleagues in the United States has shown that they are equally unaware of such differences. These subjective observations are preliminary and the hypotheses are highly speculative, both of which will require rigorous scientific proof and validation. These observations can be arbitrarily divided into two broad categories.

Normal Variants for the Local Population

There appear to be more and larger mesenteric lymph nodes with no evidence of acute gastrointestinal diseases in patients in Singapore. Clusters of lymph nodes greater than 6 mm are seen frequently. In addition, the appendix appears to be longer, sometimes measuring more than 12 cm. Both of these findings may be related to the frequency of gastrointestinal infections, because lymph nodes often enlarge during acute infection and may stay prominent after the acute event, whereas the appendix is said to be the source of repopulation of normal bacterial flora in the gut after each episode of gastrointestinal infection.

Diseases

The number of men with asymptomatic cholelithiasis and the number of patients with hyperplastic cholecystoses (both limited and diffuse type) and fatty liver at CT in both sexes in Singapore seem to be higher than I used to see in the United States. In addition, renal calculus disease is more widespread. Although differences in diet (more fried food and higher purine content in food in Singapore) may account for higher prevalence of both diseases, hotter weather (requiring higher water intake for adequate hydration) also may lead to renal stone disease (11).

As I mentioned previously, the frequency of aortic dissection appears higher than that seen in the United States and may be related to the reluctance of patients to take antihypertensive medication on a long-term basis, because uncontrolled hypertension has been shown to be the most important treatable risk factor for acute aortic dissection (12).

Conclusions

It has been well established that certain diseases (eg, adult polycystic kidney disease) are genetically linked and others are related to behavior (eg, smoking) and environment (eg, gastrointestinal infections from contaminated food or water). Although physicians’ approach to diagnosis and treatment of diseases is based largely on scientific evidence, it also is influenced by the combined effects of reimbursement policy, vulnerability to medical liability, and availability of technology. Although education and socioeconomic status are known to affect patients’ access to medical care, cultural differences in how patients of various ethnic groups and countries view Western medicine have not been as well publicized in the United States. Awareness of these differences may help practicing physicians and radiologists in treating patients from Southeast Asia.