Arthrograms are an imaging modality that involves injecting radio opaque dye into the joint. Prior to the development of MRI scans and CT scans, this was the common method of diagnosing meniscal tears as the dye would flow into the tear and certain image patterns would develop on the x-rays. The use of arthrography has declined since MRI and CT scanning has developed. However, it is still occasionally ordered. MRI arthrograms can be performed and are commonly used in the shoulder to diagnose rotator cuff tears. In people who have had recent knee surgery, within six months or so, a plain MRI scan can sometimes not be accurate due to the increased signal generated from the effects of surgery, and therefore the scan can be enhanced by using an intra-articular injection of contrast which will increase the sensitivity of the scan and differentiate changes from being post-surgical to pathological changes such as a recurrent meniscal tear. In patients who cannot have MRI scans, CT arthrograms can be very useful to make a diagnosis.