BR3FYZZ
Magnetic Resonance Imaging (MRI) Sacrum and Coccyx to None with None, Other Contrast Approach
Procedural Specifications
| Clinical Axis | Detail Definition |
|---|---|
| Section | B Imaging |
| Body System | R Axial Skeleton, Except Skull and Facial Bones |
| Operation | 3 Magnetic Resonance Imaging (MRI) |
| Body Part | F Sacrum and Coccyx |
| Approach | Y Other Contrast |
| Device | Z None |
| Qualifier | Z None |
Operation Definition
Computer reformatted digital display of multiplanar images developed from the capture of radiofrequency signals emitted by nuclei in a body site excited within a magnetic field
Procedure Overview
This family covers magnetic resonance imaging of the spine and other bones of the trunk - the cervical, thoracic, and lumbar vertebrae, the sacrum and coccyx, and the sternum and ribs. Rather than using x-rays, the scanner uses a strong magnetic field and radio waves to make the body's tissues emit signals, which a computer reassembles into detailed cross-sectional pictures. Because it shows soft tissue as clearly as bone, it is the study of choice when a clinician needs to see the spinal cord, nerve roots, discs, and surrounding ligaments in addition to the bony spine itself.
Patients are referred for this type of scan when they have back or neck pain that has not responded to conservative treatment, numbness or weakness suggesting nerve compression, suspected disc herniation or spinal stenosis, a possible tumor or infection in the spine, or unexplained trauma findings that plain x-rays could not clarify. It is also used before and after spine surgery to plan the approach and check on healing. The exam takes longer than an x-ray or CT and requires the patient to stay still inside the scanner, sometimes with an injected contrast agent to make certain tissues stand out more clearly.
Anatomy & Axis Detail
Sacrum and Coccyx
MRI of the sacrum and coccyx evaluates the fused terminal vertebral segments with a level of soft tissue and marrow detail that CT cannot provide, making it the preferred study for detecting sacral insufficiency fractures, which can be subtle on radiographs and CT alike, as well as for characterizing presacral masses, chordomas, and marrow infiltration from metastatic disease. It is also used to assess the sacral nerve roots as they pass through the neural foramina when radicular symptoms localize to this level. The coccyx, being small and variably curved, is imaged with attention to positioning, and coccydynia after a fall is a common indication when persistent pain does not correlate with radiographic findings. Documentation of the imaged extent, sacrum alone versus sacrum and coccyx together, affects code selection.
Contrast: Other Contrast
Other Contrast captures imaging studies using a contrast medium that is neither high- nor low-osmolar iodinated agent, such as barium sulfate for gastrointestinal studies or gadolinium-based agents for certain applications outside standard MRI classification within this axis. It is used when the contrast administered does not fit the osmolarity-based iodinated categories, distinguishing it from those specific classes and from studies performed with no contrast.
Coding & Documentation
Code assignment depends on identifying the exact body part imaged - cervical spine, thoracic spine, lumbar spine, or a combined region such as cervical/thoracic - since each has its own code and PCS does not allow a single code to stand in for an adjacent, unstudied segment. The radiology report must specify whether contrast material was used, and if so whether it was given intravenously, orally, or both, since the qualifier axis distinguishes unenhanced from enhanced studies and from combined pre/post-contrast exams. A frequent error is coding a lumbar spine MRI as a lumbosacral study when the sacrum was not actually included in the imaged field, or missing that a study was done both without and then with contrast, which requires the combined qualifier rather than a single unenhanced code.
Commonly Confused With
This family is easily confused with CT of the same axial skeleton regions, which uses ionizing radiation and a different physical technique despite covering the same anatomic sites; the report's modality line, not the clinical indication, is what determines which root operation applies. It is also distinct from MRI of the skull and facial bones, which falls under a different body system even though the cervical spine sits close to the skull base - the dividing line is the specific vertebrae or bones named in the report.