The question being multifaceted, doesn't lead to simple answers, however a study by Stanford University researchers recently published in an issue of the journal Health Affairs attempts to solve the puzzle. The research correlated Medicare claims data with U.S. censuses that recorded the number and location of MRI and CT units at four points in time.

Increasing MRI and CT facilities and their Use

• The researchers' data mining efforts uncovered that the estimated number of CT units grew more than 50 percent between 1995 and 2004, while the estimated number of MRI units more than doubled.

• In addition, there was clear relationship between the availability of imaging units and their use. For example, they found that each additional MRI unit led to 733 more MRI procedures per year among Medicare clients aged 65 and more.

• Similarly, an additional CT unit led to 2224 more procedures conducted annually.

The Costs and Benefits of Imaging Technology Use

Each additional MRI unit associated with 733 more MRI procedures per year among Medicare beneficiaries age 65 and older, adds US$550,000 to annual Medicare costs. On similar lines, each additional CT unit associated with 2224 more procedures per year, leads to a figure of US$685,000 in Medicare costs.

Further, at an individual level, the costs associated with increasing imaging tests not only include the costs associated with the procedures performed with this equipment, but also include the costs incurred as a consequence of imaging, in the form of subsequent healthcare such as follow-up tests, etc.

At the same time, imaging can lead to an earlier diagnosis of a treatable abnormal medical condition and as a result improved outcomes. Even if the tests don't uncover a problem, they can still provide valuable information to guide medics in ruling out suspected abnormalities and advise further tests, prescription drugs and care.
While it might be a relief for patients to see their own tests turn out negative results, studies have found that sending patients for additional testing can produce anxiety that persists even when the tests eventually show up as "negative."

On another front, considering imaging in comparison to older generation diagnostic equipment and procedures e.g CT angiography (an imaging procedure) and a catheter-based angiography (an older invasive procedure which carries the risk of complications, including potentially life-threatening embolisms), imaging may offer higher sensitivity, specificity, accuracy and less risk.

A related benefit is that imaging may lead to quicker and more precise diagnoses, helping initiate appropriate treatment quickly and hence lead to better outcomes.

On the whole the benefits of expanded imaging have some measurable health outcomes in addition to some less tangible of benefits. However, there still remain challenges for researchers about how to measure and analyze these benefits. In addition there's also the puzzle of the extent to which the healthcare system should pay for the less tangible benefits, which may lend themselves to be measured easily and objectively.