Get the Picture on Imaging

Increasing costs associated with diagnostic imaging are putting family physicians in a tight spot. Practitioners who order imaging are accused of driving up the cost of health care. Practitioners who resist the trend to image more and more frequently are accused of shirking their duty to patient care.

"There are a number of trends in imaging, all converging on us," said Mark Needham, M.D., co-CEO of Santa Monica Bay Physicians Health Services. "Technology is advancing and costs are exploding. Patients are demanding faster diagnosis and treatment. The penalties for delayed or incorrect diagnosis are increasing. Family docs are in the center of the storm."

The best and only defense, Dr. Needham told the American Academy of Family Physicians Scientific Assembly, is to stay on top of the constantly changing world of imaging. The plain vanilla MRI that once imaged potential stroke patients in the ER is now a diffusion-weighted MRI that doubles, sometimes triples the detection rate. The result: more patients are diagnosed in the early minutes of stroke when thrombolysis is most effective.

Trauma patients demand the newest and the best, especially athletes who live in constant fear that their rehab regimen might be delayed by a late diagnosis. For many patients, the newest and the best is a CT scan - but not if the physician realizes that MRI is the better diagnostic for skeletal trauma. MRI shows more anatomical detail, CT is more useful on moving tissues such as the heart, lung, and abdomen.

Ankle tendon subluxation, hairline femoral fractures, foot fractures, and similar injuries all show more clearly on MRI, Dr. Needham said. The real question practitioners should be asking is not MRI or CT, he added, but whether imaging is appropriate in the first place.

"You always have to start by asking two basic questions," he explained. "Will this image make a difference to the patient? And will it affect the treatment and outcome? Only when the answers are Yes do you worry about which imaging technique might be more appropriate."

Lower back pain is the classic case of overly aggressive imaging. About a third of any healthy population will show some sort of back abnormality on MRI, Dr. Needham said. The diagnostic utility of the procedure is relatively low for many patients.

"If all the patient has is lower back pain," he said, "there is no rush to MRI."

At the other extreme, MRI is the image of choice for women with breast implants who complain of breast pain.

CT is the gold standard for pulmonary embolism, Dr. Needham noted, and is finding increasing cardiovascular use.

Earlier this year, the US Preventive Service Task Force recommended that all males between the ages of 65 and 75 who have smoked more than 100 cigarettes in the lifetime be scanned for potential abdominal aortic aneurysms. The recommendation covers about 5% of the total US population.

Advanced CT units with 16 and 64 detectors are already used in academic settings to produce noninvasive cardiac angiograms. Within five years, Dr. Needham predicted, noninvasive angiograms will become standard in all settings.