72148

Magnetic resonance imaging (MRI), spinal canal and contents, lumbar; without contrast material

MRI of the lumbar spine (CPT 72148) is a sophisticated, non-invasive diagnostic imaging procedure utilized to evaluate the complex structures of the lower back, including the vertebral bodies, intervertebral discs, spinal cord, and surrounding paraspinal soft tissues. It utilizes powerful magnetic fields and radiofrequency pulses to generate detailed cross-sectional images in multiple planes, typically axial, sagittal, and coronal. This specific code, 72148, refers to a study performed without the administration of intravenous gadolinium-based contrast material. Clinically, it serves as the primary imaging modality for diagnosing mechanical and neurological conditions such as lumbar disc herniation, spinal canal stenosis, degenerative disc disease, and radiculopathy. The procedure involves the patient lying supine on a motorized table that slides into the bore of the MRI scanner. A specialized surface coil is placed over the lumbar region to maximize the signal-to-noise ratio, ensuring high-resolution images. The sequences typically include T1-weighted, T2-weighted, and STIR (Short Tau Inversion Recovery) sequences. T1-weighted images provide excellent anatomical detail and marrow visualization, whereas T2-weighted images are critical for identifying fluid, edema, and pathology within the discs or neural structures. The examination provides clear visualization of the conus medullaris, cauda equina, and the exiting nerve roots within the neural foramina. It is particularly effective at identifying compression caused by disc protrusions, ligamentum flavum hypertrophy, or osteophyte formation. Because it lacks ionizing radiation, it is the preferred alternative to CT for soft tissue evaluation. The study usually requires the patient to remain still for approximately 20 to 45 minutes to avoid motion artifacts that could degrade the diagnostic quality of the images.

Clinical Indications

  • Chronic low back pain unresponsive to at least 6 weeks of conservative therapy
  • Lumbar radiculopathy or sciatica with neurological deficits
  • Suspected lumbar spinal stenosis based on clinical presentation of neurogenic claudication
  • Evaluation of suspected lumbar disc herniation or extrusion
  • Assessment of spondylolisthesis or spondylolysis with clinical progression
  • Acute trauma to the lumbar spine with suspected cord or root injury
  • Evaluation of congenital spinal anomalies such as tethered cord
  • Pre-operative planning for lumbar spinal fusion or decompression
  • Follow-up of known lumbar spine abnormalities or stable fractures

Procedure Steps

  1. Verify patient identity and ensure clinical history matches the requested imaging area.
  2. Perform MRI safety screening for metallic implants, pacemakers, or claustrophobia.
  3. Position the patient supine on the MRI table with knees slightly flexed for comfort.
  4. Apply a dedicated multi-channel lumbar spine radiofrequency coil over the lumbar region.
  5. Acquire initial localizer sequences in three planes to center the field of view.
  6. Perform Sagittal T1-weighted sequences from T12 through the sacrum.
  7. Perform Sagittal T2-weighted sequences to evaluate for disc hydration and CSF flow.
  8. Acquire Axial T2-weighted sequences angled to the intervertebral disc spaces.
  9. Perform Sagittal STIR sequences to identify bone marrow edema or inflammatory changes.
  10. Review all acquired images for technical adequacy and transfer to the PACS system.

Coding Guidelines

  • Report 72148 for a lumbar MRI performed without intravenous contrast.
  • If contrast is administered during the same session, do not report 72148; instead, report 72149 or 72150 as appropriate.
  • Use modifier 26 when billing only for the radiologist's interpretation of the study in a facility setting.
  • Use modifier TC when billing for the technical component in a non-facility setting.
  • For MRI of the sacrum and coccyx performed at the same session, refer to CPT 72159, though 72148 specifically covers the lumbar levels.
  • Verify that documentation supports medical necessity, such as failed conservative management for at least 6 weeks.

Associated ICD-10 Codes