Progress in medical technologies
continues to transform health care delivery and to improve life expectancy and quality of
life, but it is also one of the main drivers of rising health expenditure across OECD
countries. This section presents data on the availability and use of two diagnostic
technologies - computed tomography (CT) scanners and magnetic resonance imaging (MRI)
CT scanners and MRI units help
physicians diagnose a range of conditions by producing cross-sectional views of the inside
of the body. Unlike conventional radiography and CT scanning, newer imaging technology
used in MRI units does not expose patients to ionising radiation which may cause damage in
The availability of CT scanners and
MRI units has increased rapidly in most OECD countries over the past two decades. Japan
has, by far, the highest number of MRI and CT scanners per capita, followed by the United
States for MRI units and by Australia for CT scanners (Figure 4.2.1
and Figure 4.2.2). At the other end of the scale, the number of
MRI units and CT scanners were the lowest in Mexico, Hungary and Israel.
Data on the use of MRI and CT scanners
are available for a smaller group of countries, excluding Japan. Based on this more
limited country coverage, the number of MRI and CT examinations per capita is highest in
Greece and the United States, followed by Luxembourg and Iceland (Figure 4.2.3 and Figure 4.2.4).
In Greece, most CT and MRI scanners
are installed in private diagnostic centres, and only a minority are found in public
hospitals. There are no regulations concerning the purchase of MRI units in Greece, while
the purchase of CT scanners requires a licence that is granted following a review that is
based on a criterion of population density. There are also no guidelines concerning the
use of CT and MRI scanners (Paris et al., 2010). The
current situation has led the Greek Ministry of Health and Social Solidarity to establish
an expert committee to review regulations and propose new criteria for the purchase of CT
and MRI scanners.
In the United States, evidence
suggests that there is an overuse of CT and MRI examinations. Between 1997 and 2006, the
number of scans in the United States increased dramatically while the occurrence of
illnesses has remained constant (Smith-Bindman et al.,
2008). Furthermore, payment incentives allow doctors to benefit from exam referrals which
also increase the likelihood of overuse. Many studies have attempted to assess tangible
medical benefits of the substantial increase in CT and MRI examinations in the United
States but have found no conclusive evidence of such benefits (Baker et al., 2008).
Other OECD countries are also
examining ways to promote the more rational purchase and use of diagnostic technologies
(OECD, 2010b). In the United Kingdom, the National Institute for Health and Clinical
Excellence set up in 2009 a Diagnostics Advisory Committee to evaluate and make
recommendations for the appropriate use of diagnostic technologies within the NHS in
England (NICE, 2009).
Definition and comparability
For MRI units and CT scanners, the
numbers of equipment per million population are reported. MRI exams and CT exams
relate to the number of exams per 1 000 population. In most countries, the data cover
equipment installed both in hospitals and the ambulatory sector.
However, there is only partial
coverage for some countries. CT scanners and MRI units outside hospitals are not
included in some countries (Belgium, Germany and Spain). For the United Kingdom, the
data only include scanners in the public sector. For Australia, the number of MRI
units and CT scanners includes only those eligible for reimbursement under Medicare,
the universal public health system (in 1999, 60% of total MRI units were eligible for
Medicare reimbursement). Also for Australia, MRI and CT exams only include those for
outpatients and private inpatients (excluding those in public hospitals). MRI and CT
exams for Ireland only cover public hospitals, while Korea and the Netherlands only
include publicly financed exams.