Radiology Services

The Department of Radiology at the University of Michigan Health System provides imaging services to aid in the diagnosis and treatment of disease for outpatients and inpatients. Our radiologists provide a wide range of imaging tests from the common [X-rays, mammography, computed tomography (CT or CAT) scans, magnetic resonance imaging (MRI)] to the advanced [interventional radiology, nuclear medicine, positron emission tomography (PET)].

Some imaging tests expose patients to small amounts of radiation. While these tests are important for accurate diagnosis of disease and injury, they should be provided only when needed to avoid unnecessary exposure.

The following performance measures are designed to evaluate use of unnecessary tests and exposure. These measures are produced by the Centers for Medicare and Medicaid Services (CMS), a federal agency that has a program that evaluates quality of care delivered at hospitals nationwide. The explanations of the importance of each measure and how to interpret the results are provided by CMS.

Combination (or Double) Chest CT Scans
Lower Value = Better Performance

Details

Why is This Measure Important?

This measure reports the percentage of outpatient CT scans of the chest that were "combination" (double) scans.

A "combination" CT scan means that the patient gets two CT scans - one scan without contrast followed by a second scan with contrast. (“Contrast” is a substance put into the patient's body before the scan begins, to help make parts of the body stand out more clearly.)

Combination scans involve additional radiation exposure and risks associated with use of contrast. Standards of quality care say that most patients who are getting a CT scan of the chest should be given a single CT scan rather than a "combination" CT scan. (Although combination CT scans are appropriate for some parts of the body and some medical conditions, combination scans are usually not appropriate for the chest.)

The range for this measure is 0 to 1.0. If a number is very close to 1.0, it may mean that the facility is routinely giving patients combination CT scans of the chest when a single scan is all they need. Giving patients two scans when they only need one needlessly doubles their exposure to radiation:

  • Radiation exposure from a single CT scan of the chest is about 350 times higher than for an ordinary chest X-ray.
  • For combination CT scans, radiation exposure is 700 times higher than for a chest X-ray because the patient is given two scans.

If you need to have a CT scan of the chest, talk with your doctor about what’s best for your medical condition:

  • Do you need a single scan - either with or without contrast - or is a combination scan necessary?

Is using contrast appropriate for your medical condition?

How is UMHS Performing?

The most recent rate reported for the University of Michigan Health System was 0.005, which was much lower than 1 and much lower than the national average, demonstrating that UMHS is judicious and rarely uses double chest CT scans.

UMHS Source: Hospital Medicare administrative data.
Comparison Group Source: National average from CMS/ Hospital Compare.

MRI for Low Back Pain

Details

Why is This Measure Important?

This measure reports the percentage of outpatients with low back pain who had an MRI without trying recommended treatments first, such as physical therapy.

An MRI (magnetic resonance imaging) is a test that uses a powerful magnetic field and a computer to produce detailed pictures of the inside of the body (bones, organs and other body parts). Since MRIs use magnets rather than X-rays, there is no radiation risk.

Although MRIs can be helpful for diagnosing low back pain, MRIs can be used too much.

  • Usually, low back pain improves or goes away within six weeks and an MRI is not needed.
  • Standards of care say that most patients with low back pain should start with treatment such as physical therapy or chiropractic care, and have an MRI only if the treatment doesn't help.
  • Finding out whether treatment helps before having an MRI is better and safer for most patients because it avoids the stress, risk and cost of doing MRIs that patients don't need.

If a number is high, it may mean that the facility is doing unnecessary MRIs for low back pain. For some patients with certain conditions, getting an MRI right away is appropriate care. Patients with these conditions are not included in this measure.

How is UMHS Performing?

The University of Michigan Health System had a lower rate than the national average, demonstrating that UMHS does not perform unnecessary MRIs.

UMHS Source: Hospital Medicare administrative data.
Comparison Group Source: National average from CMS/ Hospital Compare.

Combination (or Double) Abdominal CT Scans

Lower Value = Better Performance

Details

Why is This Measure Important?

This measure reports the percentage of outpatient CT scans of the abdomen that were "combination" (double) scans.

A "combination" CT scan means that the patient gets two CT scans - one scan without contrast followed by a second scan with contrast. ("Contrast" is a substance put into the patient's body before the scan begins, to help make parts of the body stand out more clearly.)

Combination scans involve additional radiation exposure and risks associated with use of contrast. The range for this measure is 0 to 1.0. If a number is very close to 1.0, it may mean that the facility is routinely giving patients combination CT scans of the abdomen when a single scan is all they need. Giving patients two scans when they only need one needlessly doubles their exposure to radiation:

  • Radiation exposure from a single CT scan of the abdomen is about 11 times higher than for an ordinary X-ray of the abdomen.
  • For combination CT scans, radiation exposure is 22 times higher than for an X-ray of the abdomen because the patient is given two scans.

If you need to have a CT scan of the abdomen, talk with your doctor about what's best for your medical condition:

  • Do you need a single scan - either with or without contrast - or is a combination scan necessary?

Is using contrast appropriate for your medical condition?

How is UMHS Performing?

The most recent rate reported for the University of Michigan Health System was 0.072 which was much lower than 1.00 and lower than the national average, demonstrating that UMHS is judicious and provides combination CT scans of the abdomen less often than hospitals nationally.

UMHS Source: Hospital Medicare administrative data.
Comparison Group Source: National average from CMS/ Hospital Compare.

Follow-Up Mammogram or Ultrasound

Details

Why is This Measure Important?

This measure reports the percentage of outpatients who had a follow-up mammogram or ultrasound within 45 days after a screening mammogram.

A screening mammogram is an X-ray of the breast to check for possible breast cancer. When a screening mammogram shows signs of possible breast cancer, the patient is asked to come back for a follow-up appointment. A follow-up usually means having more tests (mammograms, an ultrasound or both).

Medical research shows that there may be a problem if a facility has either very low or very high numbers of follow-ups (Note: The numbers that follow are most appropriately applied to women who are 65 or older who have Original Medicare):

  • A number much lower than 8% may mean there's not enough follow-up and it's possible that signs of cancer are being missed.
  • A number much higher than 14% may mean the facility is doing too much unnecessary follow-up.
    • Reasons could include poor technique (blurry X-rays that need to be repeated) or a lack of skill or experience interpreting the screening mammograms.
    • Whatever the reason, unnecessary follow-up is stressful to patients and results in needless exposure to radiation. (There is no radiation exposure for ultrasounds because they don't use X-rays.)

How is UMHS Performing?

The most recent rate reported for the University of Michigan Health System was 9.6%, which was neither too low nor too high and demonstrates that UMHS is judicious in its use of follow-up mammograms and ultrasounds.

UMHS Source: Hospital Medicare administrative data.
Comparison Group Source: National average from CMS/ Hospital Compare.