C型臂的field of view视场

The field of view (FOV) is defined as the dimensions of the exact anatomic region included in a scan. In MR, the FOV may be square or asymmetric. Depending on the vendor, it is specified in millimeters or centimeters. The FOV is also the mathematical product of the acquisition matrix and the pixel dimensions. For example, if 512 readout and 256 phase-encoding steps are specified in a scan for which the pixel dimensions are chosen to be 0.45 × 0.9 mm, the FOV would be 512 × 0.45 mm = 230 mm by 256 × 0.9 mm = 230 mm (and thus in this instance a square FOV, despite the use of a rectangular pixel). Head imaging is typically performed today with a FOV of 230 mm or less, to achieve high in-plane spatial resolution. Depending on body habitus, the FOV for a scan of the upper abdomen may be as large as 400 mm.