Influence of Contrast Media on Bone Mineral Density (BMD) Measurements from Routine Contrast-Enhanced MDCT Datasets using a Phantom-less BMD Measurement Tool

Abstract

ZUSAMMENFASSUNGZiel Ziel der Studie war den Einfluss einer intravenösen Kontrastmittelgabe auf phantomlos gemessene volumetrische Knochendichtewerte im Routine-MDCT zu evaluieren. Zusätz-lich sollte eine Formel zur Berechnung der wahrheitsgetreuen Knochendichte aus arteriell und venös gemessenen Werten aufgestellt werden. Material und Methodik 112 postmenopausale Frauen imAlter von 40 bis 77 Jahren (mittleres Alter 57,31; SD 9,61), die ein triphasisches MDCT (nativ, arteriell und venös) ABSTR AC TAim To evaluate the differences in phantom-less bone mineral density (BMD) measurements in contrast-enhanced routine MDCT scans at different contrast phases, and to develop an algorithm for calculating a reliable BMD value.Materials and Methods 112 postmenopausal women from the age of 40 to 77 years (mean age: 57.31 years; SD 9.61) who underwent a clinically indicated MDCT scan, consisting of an unenhanced, an arterial, and a venous phase, were included. A retrospective analysis of the BMD values of the Th12 to L4 vertebrae in each phase was performed using a commercially available phantom-less measurement tool.Results The mean BMD value in the unenhanced MDCT scans was 79.76 mg/cm³ (SD 31.20), in the arterial phase it was 85.09 mg/cm³ (SD 31.61), and in the venous phase it was 86.18 mg/cm³ (SD 31.30). A significant difference (p < 0.001) was found between BMD values on unenhanced and contrastenhanced MDCT scans. There was no significant difference between BMD values in the arterial and venous phases (p = 0.228). The following conversion formulas were calculated using linear regression: unenhanced BMD = -2.287 + 0.964 * . The intrarater agreement of BMD measurements was calculated with an intraclass correlation (ICC) of 0.984 and the interobserver reliability was calculated with an ICC of 0.991.Conclusion Phantom-less BMD measurements in contrastenhanced MDCT scans result in increased mean BMD values, but, with the formulas applied in our study, a reliable BMD value can be calculated. However, the mean BMD values did not differ significantly between the arterial and venous phases. Key points▪ BMD can be assessed on routine CT scans using a phantom-less tool.

The Influence of Contrast Media on Calcium-based Imaging of the Spine in Dual-layer CT

“…The ndings of this study are in line with previous studies suggesting that the application of CM results in a systematic overestimation of CT-derived BMD [24][25][26]. Hence, CT attenuation values of osseous structures obtained from non-contrast and contrast-enhanced acquisitions cannot be readily compared and, most importantly, thresholds suggested for non-contrast acquisitions might not be applicable to contrast-enhanced acquisitions, and vice versa.…”

“…Since the current state of research suggests that CT-derived BMD is substantially higher for acquisitions with iodinated contrast media (CM) application than for non-contrast acquisitions, the latter study was restricted to CT examinations without CM injection [24][25][26]. The aim of the present study was to examine the impact of CM application on CT-derived BMD in VCa and therefore to extend the applicability of calcium-only imaging for osteoporosis screening to contrast-enhanced CT acquisitions.…”

Imaging of the Osteoporotic Spine – Quantitative Approaches in Diagnostics and for the Prediction of the Individual Fracture Risk

“…Yet, contrast media can drastically change attenuation within vertebral bone, which is due to its high vascularization 28 . Recently, it has been reported that the increase in vBMD values related to trabecular bone contrast perfusion could reach a plateau at approximately 7–9 %, which may be irrespective of the exact contrast phase and would make it comparatively easy to correct for 29 30 . However, universal correction for contrast-enhanced CT has not been achieved and is the subject of ongoing research, with many factors influencing attenuation values such as contrast phase and volume of injected contrast medium, heart ejection fraction, and extent of vascularization 18 19 .…”

Opportunistic Screening Techniques for Analysis of CT Scans

“…Iodine-containing contrast agents are frequently administered prior to a CT scan in order to increase the contrast of blood-containing vessels and tissues. These contrast agents increase CT values [ 34 , 43 , 44 , 74 , 75 ]. The impact on BMD depends on the amount of contrast agent, i.e., the concentration within the bone of interest at the time of the CT scan.…”

“…In some studies using datasets with and without contrast of the same subject, linear regression correction techniques were developed [ 34 , 45 , 76 , 77 ]; however, it is not entirely clear whether these techniques apply to the different scenarios in clinical routine and whether the linear correction factors obtained for one scanner can directly be used for different scanners and scan protocols [ 46 ]. Nevertheless, high correlations and good agreement between CT scans with and without contrast using linear corrections have been reported [ 74 , 76 , 77 ]. In the case of internal calibration, the change in the HU values of the internal reference materials after contrast administration remains to be studied [ 76 ].…”