Evaluation of the diagnostic accuracy of CT scan of the abdomen and thorax compared with DXA as the standard reference in patients with suspected osteoporosis

Abstract

Osteoporosis is the most widespread metabolic bone diseases, which can reduce bone strength and increases risk of bone fracture. Diagnostic methods have been improved in recent decades in a way that the disease are diagnosed prior to the fracture. The basis of diagnosis is BoneMineral Densitometry (BMD) measurement, which is defined by WHO Committee. A small number of studies have been carried out on BMD using findings of MDCT. This study intends to examine BMD of persons over 50 years old of age, by using abdomen and thoracic CT scan and DEXA as a standard reference. This analytic epidemiologic study examines 105 persons aged over 50 years old who referred to magnetic resource imaging center of Imam Khomeini Hospital (Ahwaz, Iran) for thoracic CT scanning (2014-1015). Abdomen and thoracic CT scan is performed by using MDCT (16 slices) in Imam Khomeini Hospital through daily calibration for ensuring precision of spinal CT attenuation, which is an indication of grounded BMD. Hounsfield number of the first lumbar spine (L1 of HU) and spines of L1-L4 are measured in thoracic images and abdominopelvic images by mapping Region of Interest (1cm2) in trabecular bone of middle level of spine and avoiding spinal venous level. DEXA of the first lumbar spine is performed by using Osteosys DEXAMUTT. Then, HU findings of CT scan are compared with DEXA results and are statistically analyzed. Present study patients are 40 normal persons, 48 Osteopenia patients, and 17 Osteoporosis patients. ROC analysis indicates in a case that L1 of Hu is greater than 159.5, the persons are diagnosed as normal. Otherwise, they are Osteopenia and/or Osteoporosis. Where L1 of Hu is greater than 101.5, the persons are diagnosed as normal or Osteopenia. Conversely, they are viewed as Osteoporosis. This result is also true for L2-L4. HU and DXA can e replaced with each other in clinical conditions. Generally, CT scan can effectively diagnose Osteopenia and Osteoporosis especially in females. Risky persons should be studied for preventing unsatisfied consequences such as fracture.