Dual-energy CT as good as MRI for diagnosing wrist fractures

Written by Medha Baranwal Baranwal Published On 2018-05-19T19:20:35+05:30 | Updated On 19 May 2018 7:20 PM IST

Dual-energy computed tomography (DECT) is a useful tool for identifying bone marrow edema in the setting of acute wrist fractures, providing an alternative to magnetic resonance imaging (MRI), according to a study published in the American Journal of Roentgenology.

The study was conducted by Ismail T. Ali, Department of Radiology, Vancouver General Hospital, Vancouver, Canada, and colleagues to determine the utility of DECT for assessing carpal fractures and to obtain an attenuation value cutoff (in Hounsfield units) to identify bone marrow edema due to an acute carpal fracture.

Dual-energy CT utilizes two separate energy sets to examine the different attenuation properties of matter, having a significant advantage over traditional single energy CT. Independent attenuation values at two energy sets can create virtual non-contrast images from contrast-enhanced imaging as well as delineate the composition of renal calculi and arterial plaque.

Different dual energy technologies include dual source dual energy, single source dual energy and single source dual layer.

In this retrospective study, 24 patients who presented with wrist fractures from September 3, 2014, through March 9, 2015, underwent imaging with DECT (80 and 140 kVp). Using the three-material decomposition algorithm specific for virtual noncalcium to construct images, two radiologists identified carpal fractures and associated bone marrow edema. Readers noted the attenuation at areas with and without bone marrow edema. The cutoff value was obtained by ROC analysis and was internally validated on 13 separate patients with suspected wrist fractures.

Important findings:

CT attenuation was significantly higher in areas of bone marrow edema than in areas without it.

A cutoff of 5.90 HU allows detection of bone marrow edema associated with acute wrist fractures with 100% sensitivity and 99.5% specificity, compared with visual DECT interpretation.

In the 13 validation cases, the cutoff of 5.90 HU identified bone marrow edema with 100% accuracy, compared with visual interpretation.

Kappa values were 0.83 between the two readings by reader 1, and 0.73 and 0.96 comparing the two readings of reader 1 with the reading by reader 2.

"DECT is a useful tool for identifying bone marrow edema in the setting of acute wrist fractures, providing an alternative to MRI. A cutoff value of 5.90 HU can be used for accurate diagnosis and exclusion of carpal fractures," concluded the authors.

For further information click on the link: 10.2214/AJR.17.18673

bone marrow edemacarpal fracturesComputed tomographyCTDECTDr Ismail T AliDual-energy computed tomographyHounsfield unitsIsmail T Alimagnetic resonance imagingMRIradiologywrist fractures

Source : With inputs from AJR

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Medha Baranwal Baranwal