Test

Description

Normal

Abnormal

Diseases Association(s)

Comments

Plain x-rays

These are routine x-rays of different joints which can be done in a physician's office if there is a regular x-ray machine.  Multiple specified views are required in certain areas of the body to help better define the joints.  A cervical spine series require oblique views as well as anterior, posterior and lateral views.  In a patient with rheumatoid arthritis with neck symptoms, special flexion and extension views are required.  In the lumbosacral spine, anterior, posterior and lateral views are obtained but also oblique views help evaluate the lumbar facet joints.  When evaluating the sacroiliac joints, a special Ferguson view taken at an angle of 30° towards the head may help to better demonstrate these joints.  Plain knee x-rays are best accomplished with the patient standing (weight-bearing x-rays).  When evaluating x-rays of the feet, anterior, posterior and lateral views are obtained, but oblique views may show up some erosions which might otherwise be missed

Normal radiographic appearance of the joints with normal joint space remaining without any erosions, cysts or other abnormality of the bones at the joint articulation

Multiple findings may be present including joint space narrowing, erosions of the margins of the bones, cystic changes in the bone itself, thickening of the ends of the bone (sclerosis)

Loss of joint space with formation of spurs (osteophytes) and sclerosis of the bony margins all may be seen in osteoarthritis.  Joint space narrowing in particular joints with associated erosions are seen in rheumatoid arthritis.  Erosions in the sacroiliac joints with loss of joint space is typically seen in ankylosing spondylitis

Bone scan

A technetium-labeled phosphate compound, with a low radiation dose is injected through the vein.  The compound is localized to the skeleton, but may also accumulate in normal structures, in soft tissues (if abnormal) and in the kidney and urinary bladder.  After it is injected, 45 minutes to one hour later a scan is made and films of the skeleton are developed and read by the radiologist

No increased uptake by skeletal or soft tissue

An increased uptake, generally asymmetric, is observed indicating bony involvement or abnormal soft tissue collection including abnormalities of the kidney or urinary bladder

Bone or joint disorders are often associated with abnormal scans such as in arthritis, primary or metastatic tumors, stress fractures, Paget's disease, and infection (osteomyelitis), or old healed fractures

A very helpful way to determine subtle fractures not seen on routine x-rays.  This is particularly the case in osteoporotic patients where the fractures may be harder to see

Computerized axial tomography (CT scan or CAT scan)

A CAT scan involves making multiple cross-sectional films to a particular area.  A computer is then able to reconstruct and combine these digital images with different gradations of light gray to very dark gray depending on whether the CT is examining fluid, gas, fat or bone.  Contrast material may be given with the CT scan to help define blood vessels or soft tissue areas.  The computer then reconstructs the image three-dimensionally

Normal structures seen without any pathology present

May demonstrate bony tumors,  hidden fractures or bony infection (osteomyelitis).  Difficult to evaluate joints such as the temporomandibular joint, sternoclavicular joint or sacroiliac joint may also be shown more clearly with CT scanning.  A CT scan may also be used in the lumbar spine for diagnostic purposes

CT scan may show up insufficiency fractures of the pelvis and other occult fractures that were missed on plain films.  CT scanning may show evidence of bony tumors.  It is capable of demonstrating lumbar disk herniation.  It may show evidence of sacroiliitis more clearly than a plain x-ray.  It is helpful in post-trauma patients in showing evidence of fractures of the vertebrae and the spine

Magnetic resonance imaging (MRI)

An MRI is not an x-ray film but rather is an image created when the entire patient or a limb of the body is placed into a strong magnetic field with an image then generated.  Basically magnetic impulses line up molecules in a particular direction as the field is turned on and off.  An image is then created by doing this.  MRI is particularly useful for soft tissue lesions.  It may be used in conjunction with gadolinium contrast dye.  MRI studies of the knees are able to show details of the cartilaginous surfaces and identify any tears in the meniscus which cannot be seen on plain x-ray.  It is extraordinarily helpful for demonstrating compression of the spinal cord in the cervical and lumbar spine

Normal anatomy without pathologic abnormalities seen

Will depend on the area viewed.  In the spine, disc herniations and compression of the spinal cord may be seen easily on lateral views.  Evidence of narrowing of the spinal column with compression of the cord (stenosis) also may be shown on an MRI

An MRI is particularly useful in the cervical spine.  It may demonstrate cervical stenosis.  Also if there is impingement (pressure) on the cord due to atlantoaxial subluxation at C1 and C2 as seen in rheumatoid arthritis, then an MRI with the patient in a flexed position in the neck may readily demonstrate this compression.  Lumbar disc disease and lumbar stenosis are nicely demonstrated on MRI.  Cartilaginous tears in the knees causing buckling and locking may be demonstrable on MRI.  MRI may also be helpful to evaluate particular organs.  An MRI of the brain may show lesions in SLE with central nervous system involvement.  An MRI of the shoulder may show evidence of a tear of the rotator cuff tendon

Ultrasound

This is a technique involving the use of sound waves to create an image.  It is used over the calf to evaluate for any clots in the deep veins, (deep vein thrombosis).  It also may be used in the popliteal space behind the knee to demonstrate evidence of a cyst.  It can be used in the shoulder to demonstrate pathology including rotator cuff abnormalities.  It is used to evaluate whether there is any narrowing of the carotid arteries due to plaque.  Ultrasound of the pelvis helps to evaluate the reproductive organs including the ovaries.  Ultrasound may be used as a screening technique to evaluate the heel in osteoporosis.

Normal ultrasound results without any abnormal tissues, swelling, circulatory abnormalities, etc.

Evidence of clotting of the deep venous system, evidence of a pathologic accumulation of fluid or a cyst.  Evidence of torn rotator cuff tendon in the shoulder as some examples of abnormalities

Ultrasound is useful for showing evidence of a popliteal or Baker's cyst behind the knee.  It may demonstrate dissection of the cyst down into the calf.  It is also capable of showing evidence of a deep vein thrombosis in the calf.  It can be used to demonstrate rotator cuff tears.  It may be used to evaluate evidence of masses with pelvic ultrasound.  Also abdominal ultrasound may be used to identify evidence of gallstones or gallbladder enlargement, or liver abnormalities.  It may be used to identify circulatory blockage due to plaque such as in the carotid arteries.  An ultrasound technique involving the heel may be used as a screening test for osteoporosis, but definitive testing with DEXA scan may still be required

Dual Energy X-ray Absorptiometry (DEXA)

This procedure involves placing the patient on an open table and having two beams of low level X-irradiation passed through the lumbar spinal area as well as the head and neck of the femur.  The computer is then able to collect information as to how readily the x-ray beam passed through the bone.  If the bone is dense, then it will impede the x-ray beam moreso. These results are then translated into bone mineral density readings and compared to a young healthy population for that gender

Less than -1 standard deviations from normal as compared to a healthy population

-1.0 to -2.5 standard deviations below the normal healthy population indicates evidence of osteopenia. 

Less than -2.5 means the patient has osteoporosis. 

For each loss of 1 standard deviation below normal, the risk of fracture doubles.  Once patients are diagnosed and then started on treatment, the DEXA scan may be followed at one to two year intervals to see if the treatment is effective or not