Ligament Tears Effectively Identified with Dual-Energy CT in the ER

Dual-energy computed tomography (CT) is an effective way to assess emergency room (ER) patients with possible anterior cruciate ligament (ACL) tears.

ACL tears are one of the most frequent ligamentous injuries of the knee; they are not typically diagnosed in the ER because they cannot be visualized on common radiographs.

Researchers from the Mayo Clinic (Rochester, MN, USA) imaged the knees of 27 patients utilizing dual-energy CT. Sixteen of the patients had validated ACL tears, while 11 had no trauma history, according to Dr. Katrina Glazebook, a lead author of the study.

The images were reviewed by a musculoskeletal subspecialty trained radiologist and one senior level radiology resident. The subspecialty-trained radiologist was 94% effective in detecting the ACL tears on dual-energy CT; the resident had an 87% accuracy rate, according to Dr. Glazebrook. “While this is a new use for dual energy CT, the images were of sufficient spatial resolution and diagnostic quality that radiologists with various levels of expertise in musculoskeletal imaging could accurately identify the tears,” she said.

Dual-energy CT scanning can also be used to assess bone bruise or contusion within the bone marrow, added Dr. Glazebrook. “While MRI [magnetic resonance imaging] is considered the gold standard for evaluation of internal derangement of the knee, MRI is rarely used in the emergency department because it requires a longer scan time [30–40 minutes in which the patient has to keep his or knee in what can be an uncomfortable position] as compared to CT [few seconds]. MRI is usually not readily available and it can be more costly than CT,” added Dr. Glazebrook. “Using dual energy CT to identify significant internal derangement of the knee early can facilitate treatment planning for patients with knee trauma.”

The study’s findings were presented April 16, 2013, at the American Roentgen Ray Society (ARRS) annual meeting held in Washington DC (USA).

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Mayo Clinic