How specific is CT scan to confirm avn in a bone in compare to MRI and bone scan? ?

MRI or bone scan. It may depend on particular early avascular necrosis in hip is best detected by either MRI or bone scan by showing the decreased blood supply. It is quite specific in majority of cases. Ct can detect later changes of avn such as sclerosis of dead bone or fracture of femoral epiphysis. Avn in small bones of hands and feet may be easier detected by mr examination.
CT is good but. Diagnosis on ct takes specific anatomical changes which can be identified at earlier stages by bone scan and mri. Mri is probably best as you can see marrow changes ( edema, etc. ) and bone changes ( fracture/destruction, if present , at the same time).
MRI is best for... New onset/recent avn. Bone scan is next, especially with a technique called spect/ct, and ct is third. Once avn is being repaired by the body, it can be seen on ct as new bone formation.
Good question. You really want to detect avn in early stage to enable early intervention and avoid prosthetic hip replacement! more important question is how sensitive imaging modality in detecting early avn. Mri reported sensitivity of 97% & specificity of 98% in the diagnosis of avn of the hip. This is more sensitive & specific than ct or bone scan. Ct is not specific unless asterisk sign is appreciated.

Related Questions

Possiblity of missed undisplaced talus neck fx union without surgery. Missed for 3 month. No avn found after 12 week confirmed by bone scan and MRI?

Yes . If it is undisplaced it can go on to union but you would need to limit wt bearing and activity / no smoking as smolers always heal less well/ optimize vitd level / and maybe ultrasound stimulator called an exogen unit fractures are usually best seen on ct scan and this is the best way to follow the progression to union / these are difficult problems / best of luck. Read more...
Yes. Yes, you can confirm avn after 12 weeks with bone scan or MRI or ct scan or even xrays (usually at 6-8 weeks and the sign is called hawkin's sign). Hope that helps! Read more...

Is it safe with walking on hair line fractured talus bone. Minimal pain but swelling on ankle. Avn is not confirmed in CT scan.

AVN. Is always the main concern of talus fractures so play it safe and be non weight bearing. Read more...
Probably not. It is always better to take the pressure off particularly if there is swelling . It does not mean that you should not walk but use the boots you can buy from pharmacies or medical supply offices until you see your orthopedic doc. Do not forget to put ice pack on the swollen ankle , will help with the swelling and pain . You might as well take over the counter alive or advil (ibuprofen). Read more...

Are there bone tumors that do not show up on X-ray or CT but do show up on bone scan? Can't have MRI (icd)

Not really. Bone tumors are mostly evaluated with ct and x-ray. The extent of involvement can be evaluated with an MRI (usually to assess the soft tissue extension). A bone scan is used only to evaluate distant lesions that may have travelled away from the original tumor. Some tumors do not light up on bone scan. Read more...
Yes. Often the bone scan will show the tumor prior to it being seen on x-ray or ct, especially if you get an f18 Fluoride pet/ct bone scan. Read more...
Yes. X-ray is the right place to start the evaluation for bone lesions including tumors. However, since you cannot get an mri, a nuclear medicine study should be considered. Bone scan is an option. Others include spect/ct and pet/ct. These exams combine the benefits of nuclear medicine (like bone scan) and ct. Please note they also combine the risks of the 2 exams, namely increased radiation exposure. Read more...
Most seen on X-ray. Most primary bone tumors are evident on plain radiographs and ct exam. Mr is usually used to be exact about extent of involvement in soft tissues or marrow. Mr helps surgeon in planning extent of tumor for surgery. Bone scan and pet?Ct are used usually not to make diagnosis of primary bone tumor but extent of spread to other areas of body. Pet/ct is most sensitive and accurate detecting metastases. Read more...
Possibly. Nuclear medicine bone scan is very sensitive for certain types of bone tumors and can show a lesion that is not yet apparent on x-ray or ct. Depends on the type of tumor. Read more...

Without infection symptoms what else can cause a bone scan to light up? With nothing on CT or xray (no MRI icd) just excruciating pain in the hip.

Several things. The bone scan is very sensitive to bone metabolism. The bone can react to repair various stimuli. Infectious synovitis or bone infection is one cause. Arthritis, avascular necrosis ( decreased blood supply), traumatic change, chondrolysis (decreased cartilage), and certain tumors are other causes of positive bone scan and hip pain. Insufficiency fractures due to demineralization can also occur. Read more...
Many things. Many other disease processes can cause increased activity in the bone with a nuclear study. Fracture or bone stress, significant degenerative changes, avascular necrosis, soft tissue inflammation, and more. Talk about this finding with your Nuclear Physician and Primary Care Doctor. Read more...