DECT May Improve Detection of Bone Marrow Metastases
Leesburg, VA, February 15, 2019—Dual-energy CT (DECT) with hydroxyapatite (HAP)-water material decomposition may improve the detection of bone marrow metastases, and especially subtle isodense tumors, according to a study published in the February 2019 issue of the American Journal of Roentgenology (AJR).
For this study, “Detection of Lumbar Spine Osseous Metastases Using Dual-Energy CT: Phantom Results and Preliminary Clinical Validation,” authors Huang et al. sought to test and validate algorithms developed from phantom studies to identify lumbar bone metastases that may be missed or misinterpreted on other imaging modalities.
In patients with cancer, the most common site of metastasis after liver and lung is in bone. Using conventional single-energy CT to detect early isodense lumbar spine metastases can be challenging because there may be no or very little difference in attenuation of these tumors and bone marrow. DECT can help to differentiate and classify these tissues using distinct attenuation differences.
In this study, 51 3D-printed semianthropomorphic lumbar spine phantoms embedded with 75 simulated tumors were scanned with and without outer torso-attenuating encasement. Also included in the study were six clinical abdominopelvic DECT scans with nine nearly isodense lumbar spine tumors that had been missed in the clinical report but confirmed with other scans.
Two board-certified radiologists independently reviewed the 70-keV virtual monochromatic and material decomposition images (HAP-water, water-HAP, cortical bone–water, water–cortical bone) to determine the presence or absence of tumors and then recorded the sensitivity of tumor detection, tumor conspicuity, and image quality. Results between image constructions were compared; readers viewing the HAP-water material decomposition images were able to detect tumors initially missed on the 70-keV reconstruction, which correlated with the findings in the phantom experiment
The authors believe the results call for further study to determine whether improved tumor conspicuity will result in greatly improved tumor detection. However, they stress the importance of needed improvement in CT for detecting isodense metastases and conclude that DECT with HAP-water material decomposition may contribute to better detection of bone marrow metastases. For more information, visit www.ajronline.org.
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