Jalal Jalal Shokouhi-M.D. Ali Akbar Ameri-M.D. Iranian society of radiology

Demonestration Of occult fractures by MRI

We assessed the utility of MRI in diagosis of occult bone fractures and compared with x – rays. T1 and fat saturation images was the best for this diagnosis " few patients, x – ray CT SCANS, are out of study ".

Subjects consisted 75 patients with MRI and x – ray and x – ray CT " few of them fixed in cast or splint " Result : MRI was so helpful in determining bone marrow signal and minimum edema in the bright T1 signal. MRI can't see compact bone or cortex but because of muscle and bone marrow interfaces FX line can be demonstrated by MRI as a bright line. "compact bone as a dark line "

Because of bone fractures without replasment and diastasis they can't detect by x – ray but MRI is helpful and specifically diagnostic to show delicate fracture line and other complications like adjacent bone marrow edema and fat – fluid level in the adjacent joint spaces. " hemorrhage " MRI also can show other lesions beside fracture,Tendon, menisc and …. Lesions.

MRI is reliable and method of choice for assessing fracture line in the bone and complicated condition in the adjacent joint. Other modalities like x – ray, spiral CT – SCAN can show chip bones in case of replacement and could be also negative for FX. Line but can show fat – fluid in the joint spaces an indirect sign of hidden bone marrow fracture. (opening in to the joint space)

MRI also show soft tissue contusion, dirty fat, hematoma, capsule and tendon damages.

75 traumatic patients are addmited, 52 patient was male and 23 patient was female. From all patients, 57 traumatized knees, 10 shoulders, 5 hips, 3 long bones are imaged.

Positive X – ray for FX observed in 11 cases. There was no negative MRI but negative x – ray observed in 64 cases. Slice thickness was 5 to 8 mm.

Main cause was trauma and second was osteoporosis. Our study mainly occurred in young age group because of random admission.

Bone marrow is brigh and white in T1 images, by standard T2 images it could be white, bright gray and by fat saturation, it should be dark and black. Mild or small amount of edema in bone marrow looks like a small spot on white doctors wearing and named dirty fat.

MRI has about 100 % specificity and sensitivity for occult fractures of bone by T1 and fat sat.images.

Because of high trauma incidence in this century, specially in our country and equipped centers and hospitals and high sensitivity of MRI to detect small changes in bone marrow signal and water content, traumatized bone with normal X – ray and unusual clinical complains should be check by MRI for occult or hidden fracture line.

Use of spiral CT with reformatted images in multiple plans also useful for bone chip detection. RN SCAN is not used in emergency periods but could be helpful in subacute and chronic phases. In all cases MRI should be positive.