The Impact of Contrast Media on Lumbar Spine Bone Mineral Density Measured by Quantitative Computed Tomography.

Background: Osteoporosis is a bone disease caused by decrease in bone mineral density (BMD). Quantitative computed tomography (QCT) has proven to be an effective tool to measure the BMD of the lumbar spine. Therefore, the objective of the study is to investigate the impact of intravenous contrast media (CM) on BMD of lumbar spine measured by QCT.

Methods: This is a prospective study and included a total of 141 patients (females: 71, males: 70) referred for contrast enhanced computed tomography (CECT) abdomen. First, the plain scan of abdomen was done. Contrast media was injected intravenously followed by acquisition of arterial and portovenous phase (PV) of abdomen. Plain, arterial and PV phases axial CT images were loaded on Philips BMD analysis application. A circular region of interest (ROI) measuring 30-40 mm² was placed at all five lumbar vertebrae (L1-L5) and value of BMD was obtained in mg/cm³.

Results: Paired t-test was used to compare BMD in plain, arterial and PV phase. There was significant difference (p <0.05) in BMD (L1-L5) between plain (110.86±36.61 mg/cm³), arterial (117.04±37.95 mg/cm³) and PV phase (127.52±40.9 mg/cm³). The study also noted significant difference between males and females in BMD of lumbar spine (L1-L5) for plain and CECT abdomen (p <0.05).

Conclusion: The BMD was highest for PV phase of the CECT abdomen. Therefore, the study concludes that BMD values are highly influenced by intravenous contrast media injections.