Renal cell carcinoma
Magnetic Resonance Imaging (MRI) scans provide an image of the soft tissues in the body using radio waves and strong magnets. MRI can be used instead of CT if the patient exhibits an allergy to the contrast media administered for the test. Sometimes prior to the MRI scan, an intravenous injection of a contrasting material called gadolinium is given to allow for a more detailed image. Patients on dialysis or those who have renal insufficiency should avoid this contrasting material as it may induce a rare, yet severe, side effect known as nephrogenic systemic fibrosis. A bone scan or brain imaging is not routinely performed unless signs or symptoms suggest potential metastatic involvement of these areas.
MRI scans should also be considered to evaluate tumour extension which has grown in major blood vessels, including the vena cava, in the abdomen. MRI can be used to observe the possible spread of cancer to the brain or spinal cord should the patient present symptoms that suggest this might be the case.
Femoroacetabular impingement
Radiographic assessment is often considered first line for FAI, providing a two-dimensional view of the hip joints. Anterior-posterior pelvis and a lateral image of the hip in question should be attained. A 45-degree Dunn view is also recommended. MRI imaging may follow, particularly if there is no specific evidence on radiographs, producing a three-dimensional reconstruction of the joint for better definition, to evaluate the hip cartilage, or measure hip socket angles (e.g. the alpha-angle as described by Nötzli in 2-D and by Siebenrock in 3-D). MR arthrogram had been used in the past, as it was more sensitive for picking up soft tissue lesions; however, due to improvement in technology, MRI is now considered comparable for picking up such lesions. CT is not usually used due to radiation exposure and no benefit above MRI. It is possible to perform dynamic simulation of hip motion with CT or MRI assisting to establish whether, where, and to what extent, impingement is occurring.