Converted Lumbar BMD Values Derived from Sagittal Reformations of Contrast-Enhanced MDCT Predict Incidental Osteoporotic Vertebral Fractures

• DOI: 10.1007/s00223-012-9596-3
• Publication Date: 2012-04-06T10:34:41Z
• Authors: Thomas Baum; Dirk Müller; Martin Dobritz; Petra Wolf; Ernst J. Rummeny; Thomas M. Link; Jan S. Bauer
• Keywords: Lumbar Vertebrae; Middle Aged; 03 medical and health sciences; 0302 clinical medicine; Bone Density; Multidetector Computed Tomography; Humans; Spinal Fractures; Female; Longitudinal Studies; Osteoporosis, Postmenopausal; Osteoporotic Fractures; Aged; Follow-Up Studies

We obtained baseline and follow-up bone mineral density (BMD) values of the lumbar spine from sagittal reformations of routine abdominal contrast-enhanced multidetector computed tomography (MDCT) using a reference phantom and assessed their performance in differentiating patients with no, existing, and incidental osteoporotic fractures of the spine. A MDCT-to-QCT (quantitative computed tomography) conversion equation for lumbar BMD measurements was developed by using 15 postmenopausal women (63 ± 12 years), who underwent standard lumbar QCT (L1-L3) and afterward routine abdominal contrast-enhanced MDCT. Sagittal reformations were used for corresponding lumbar BMD measurements. The MDCT-to-QCT conversion equation was applied to baseline and follow-up routine abdominal contrast-enhanced MDCT scans of 149 postmenopausal women (63 ± 10 years). Their vertebral fracture status (no, existing, or incidental osteoporotic fracture) was assessed in the sagittal reformations. A correlation coefficient of r = 0.914 (p < 0.001) was calculated for the BMD values of MDCT and standard QCT with the conversion equation BMD(QCT) = 0.695 × BMD(MDCT) - 7.9 mg/mL. Mean follow-up time of the 149 patients was 20 ± 12 months. Fifteen patients (10.1 %) had an existing osteoporotic vertebral fracture at baseline. Incidental osteoporotic vertebral fractures were diagnosed in 13 patients (8.7 %). Patients with existing and incidental fractures showed significantly (p < 0.05) lower converted BMD values (averaged over L1-L3) than patients without fracture at baseline and at follow-up. In this longitudinal study, BMD values of the lumbar spine derived from sagittal reformations of routine abdominal contrast-enhanced MDCT predicted incidental osteoporotic vertebral fractures.