Background:
Osteoporosis  is  a  common  disease  which  lead to
bone mass loss and increased bone fragility. One of the methods to reduce the risk of bone fracture is to diagnose the disease at an early stage and prevent  its progression. Bone densitometry is the common method of screening the Osteoporosis, however, recent studies have shown that CT scans which were performed for other clinical purposes can also be used for screening, by evaluating the Hounsfield unit (HU) of the first lumbar spine.
 
Objective:
The objective of this study was evaluation the feasibility  of  application  the  abdominal   (Abd) CT scans without contrast as a screening tool for anticipation the occurrence of vertebral compression fractures, according to L1 trabecular radiation attenuation.
 
Methods:
All the abdominal CT scans without contrast that had been performed during a year from 2016 to 2017 for the patients above 55 years old were assessed using images which were saved in PACS system. The HU of the trabecular region of first lumbar spine were evaluated using an ellipsoid region of interest with the same area in all the patients. Evaluation the fracture (fx) status was done using Genant semiquantitative assessment method. This method categorizes the fx into 4 groups from normal to severe fx. T-test was used for evaluation the significance of the difference between the patient who had and had not fx.
 
Results:
The CT scan of 1016 patients (447 females and 569 males with the mean age of 69.88 years old) were assessed. There were no fx in 949 patients, the average HU of the 1st lumbar spine in these group was 131.86 with SD of 41.93. 67 patients had fx with the average HU of 100.92 and SD of 47.03. According to T-test there were a significant difference (p<0.0001) between the HU of the 1st lumbar spine of the patients with and without fx in Abd CT scan.
 
Conclusion:
The Abd CT scan of the patients which were performed for other clinical purposes can be used for screening the vertebral compression fx. This method decreases the cost of diagnosis and decrease the application of unnecessary ionizing radiation and so that decrease the secondary malignancies induced by radiation. Determination of cut-off point to diagnose osteoporotic patients can be helpful for screening the median to old age patients who had more risks for this disease