CT recommended as secondary exam for elderly patients with suspected hip/pelvic fractures

A computed tomography (CT) scan may be a better choice than MRI  for secondary imaging in elderly patients with suspected hip or pelvic fracture on a negative or equivocal radiograph, according to a study published in the annual issue of the Iowa Orthopedic Journal. Indeed, the study by physicians at Regions Hospital in St. Paul, MN, indicates that CT diagnoses fractures as well as MRI, and offers other clinical and tangible benefits.¹

More than 3 million adults over 65 will be admitted to hospital emergency departments in the United States for injuries from falls, according to 2017 statistics from the U.S. Centers for Disease Control and Prevention.² Radiographs are the initial imaging exam ordered in cases of hip or pelvic pain, but an estimated 2% to 10% of exams do not show suspected fractures.³ 

Many studies have shown that hip and pelvic MRI detects subtle fractures better than does CT. But CT is more readily available in many community hospitals, and eliminates concerns about implanted metal objects and potential claustrophobia.

The study was conducted to evaluate the ability of CT and MRI to diagnose fractures in patients 50 years and older who presented with hip and/or pelvic pain after a fall between 2009 and 2013, and to determine the most efficient way to evaluate such patients in a community hospital. Researchers identified 218 patients, 36% of whom had an MRI, 61% a CT, and 3% who had both  CT and a MRI exams. The 70 fractures diagnosed included femoral neck intertrochanteric, sacral, greater trochanter, isolated pubic rami, and pelvic ring fractures.  

The cohorts had a mean age of 79 for the CT group and 76 for the MRI group. One-third had dementia, and 36% had a history of osteoporosis. Before their falls, 94% were ambulatory; 17% lived in nursing homes, and 22% lived in assisted living facilities. Just over a quarter, or 26%, had one or more contraindications to MRI.

Lead author Eileen Eggenberger, MD, and colleagues determined CT was just as likely to diagnose a fracture as MRI. “If MRI was truly significantly more sensitive to diagnose a fracture, we would expect to find a higher incidence of fracture diagnosis in the MRI-only group, or multiple patients returning with displaced fractures after negative CT. Instead, the incidence of fractures was nearly identical,” the authors wrote.

Differentiating the two groups was the length of time patients spent in the  emergency department. Patients undergoing CT spent an average 7 hours 10 minutes in the ED, compared to 8 hours 22 minutes for the MRI patients. The authors noted that the time difference could be even longer in smaller hospitals where MRI is not readily available for emergency patients with suspected non-life threatening fractures.

REFERENCES

1. Eggenberger E, Hildebrand G, Vang S, et al. Use of CT vs. MRI for diagnosis of hip or pelvic fractures in elderly patients after low energy trauma. Iowa Orthop J. 2019:39(1):179-183.
2. Centers for Disease Control and Prevention. CDC Features: Take a Stand on Falls. https://www.cdc.gov/features/older-adult-falls/index.html. Accessed September 12, 2019.
3. Dominguez S, Liu P, Roberts C., et al. Prevalence of traumatic hip and pelvic fractures in patients with suspected hip fracture and negative initial standard radiographs - a study of ED patients. Acad Emerg Med. 2005;12:366-369.