CT BMD
CT BMD / QCT / Quantitative Computed Tomography, or QCT Densitometry is a method used to measure bone mass. It is the most accurate method in evaluation of osteoporosis. A CT BMD bone mass measurement is used to assess osteoporosis in the same way a cholesterol measurement is used for coronary heart disease or blood pressure for stroke. The data is used to measure an important risk factor and determine the necessity, choice and efficacy of therapy. The principle underlying CT BMD is that normal calcified bone will absorb more x-rays than surrounding tissue so that the CT density measurement can be used to measure total bone mass within a sample of tissue.
How is CT BMD / QCT different from other methods?
CT BMD and DEXA both measure bone density. Bone is a mixture of high-turnover trabecular (spongy) bone and slowly-changing cortical (compact) bone. Unfortunately DEXA measures both these two compartments and also incorrectly includes arterial calcification and bone spurs / osteophytes in the calculation of bone mineral density. Only CT BMD isolates the metabolically-active important trabecular bone for analysis. CT BMD is not only more accurate, it is also much quicker.
How is the CT BMD examination performed?
The CT BMD examination is performed on our cutting edge CT scanner and takes approximately 5 minutes. For more information on CT scanning please review the CT section of our web site. An extremely low dose CT scan is performed of the upper lumbar vertebrae and the proximal femur. The scans are evaluated for bone mineral density and any related or incidental findings (vertebral compressions, kidney stones, etc.) are noted in the report. The average bone density of the patient is then:
- Graphically compared to age and sex matched controls.
- Related to a fracture risk threshold below which most compression fractures occur.
- Categorized as to prevalence of fractures in a similar age group and bone density.
PREPARATION
No preparation is necessary. No appointment is necessary.
It is important that you are on time for your appointment to ensure there is sufficient time available to perform the procedure. Please remember to bring any relevant films and your referral to your appointment.
RESULTS
Your procedure will take up to approximately 10 minutes, after which you may wait while the images are prepared and reported. You can also pick up the films and report at a later time.
We understand that some patients are anxious about having tests performed. If you do have any questions or concerns, please do not hesitate to ask our staff. Norwest Medical Imaging strongly advise that you return to your referring doctor, in order for your doctor to discuss your CTBMD report with you.
