Erschienen in:
01.02.2015 | Musculoskeletal
Intravenous contrast injection significantly affects bone mineral density measured on CT
verfasst von:
Esther Pompe, Martin J. Willemink, Gawein R. Dijkhuis, Harald J. J. Verhaar, Firdaus A. A. Mohamed Hoesein, Pim A. de Jong
Erschienen in:
European Radiology
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Ausgabe 2/2015
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Abstract
Objective
The objective is to evaluate the effect of intravenous contrast media on bone mineral density (BMD) assessment by comparing unenhanced and contrast-enhanced computed tomography (CT) examinations performed for other indications.
Methods
One hundred and fifty-two patients (99 without and 53 with malignant neoplasm) who underwent both unenhanced and two contrast-enhanced (arterial and portal venous phase) abdominal CT examinations in a single session between June 2011 and July 2013 were included. BMD was evaluated on the three examinations as CT-attenuation values in Hounsfield Units (HU) in the first lumbar vertebra (L1).
Results
CT-attenuation values were significantly higher in both contrast-enhanced phases, compared to the unenhanced phase (p < 0.01). In patients without malignancies, mean ± standard deviation (SD) HU-values increased from 128.8 ± 48.6 HU for the unenhanced phase to 142.3 ± 47.2 HU for the arterial phase and 147.0 ± 47.4 HU for the portal phase (p < 0.01). In patients with malignancies, HU-values increased from 112.1 ± 38.1 HU to 126.2 ± 38.4 HU and 130.1 ± 37.3 HU (p < 0.02), respectively. With different thresholds to define osteoporosis, measurements in the arterial and portal phase resulted in 7-25 % false negatives.
Conclusions
Our study showed that intravenous contrast injection substantially affects BMD-assessment on CT and taking this into account may improve routine assessment of low BMD in nonquantitative CT.
Key Points
• Routine CT may gain a role in bone attenuation measurements for osteoporosis
• Contrast media injection has substantial influence on CT-derived bone density
• Contrast-enhanced CT leads to underestimation of osteoporosis compared to unenhanced CT
• Adjusting for contrast injection phase may improve CT screening protocols for osteoporosis.