Figure 3a:

Anatomic MR images in a 62-year-old man with metastatic disease show value of chemical shift imaging, as compared with delayed contrast-enhanced imaging. (a) Axial gradient-recalled-echo in-phase (left: 10/4.4) and opposed-phase (right: 10/2.2) MR images of the pelvis are shown. There is low signal intensity throughout the pelvic bones on the in-phase image, and it is difficult to distinguish normal hematopoietic marrow in pelvic bones from tumor infiltrating marrow on this image. Opposed-phase image clearly shows there is no decrease in signal intensity in right sacrum (short arrow) and left iliac bone (long arrow), representing areas of metastatic disease. Areas of signal drop-out (in left sacrum and right iliac bone) represent hematopoietic marrow reconversion. (b) Axial static delayed contrast-enhanced fat-suppressed T1-weighted image (10/4.9) obtained 1 minute after injection again shows tumor extent in pelvis (arrows), correlating well with the opposed-phase image.