Lower Back (Lumbar Spine) CT scan (with contrast)

What it is

CT is at its strongest on bone, and the standard lumbar CT — fractures, arthritic change, the shape of the spinal canal, hardware from a previous operation — is done with no dye at all. Contrast enters the picture when the question moves off the bone and onto the tissue around and inside it. Infection in a vertebra or a disc space, a tumor deposit, and scar tissue around a nerve root all take up dye in ways that normal tissue does not, so the injection is what separates them from their surroundings. There is also a related but different study, CT myelography, in which dye is placed into the spinal canal by lumbar puncture rather than into a vein, and the CT follows; that one involves a separate procedure with its own charges. If this code has appeared on a bill or an order, it is reasonable to ask which of these was meant.

Why it is done

• To assess a suspected infection of a vertebra or a disc space
• To look for a tumor involving the bones of the lower spine or the tissue around them
• To distinguish scar tissue from recurrent disc material in someone who has had previous back surgery
• To evaluate the lower spine in a patient for whom an MRI is not possible, such as someone with an incompatible implant

What to expect

Fasting for several hours is typical when intravenous dye is planned, and staff ask beforehand about kidney function, metformin, prior contrast reactions, and pregnancy. Metal and jewelry come off. The patient lies flat on a narrow table that slides through the scanner ring, and the scan itself takes only a few minutes; staying still is the main requirement. The injection produces a brief warm flush and a metallic taste. If a myelogram was performed instead, there is a needle procedure into the lower back first, followed by a period of lying with the head raised. A radiologist interprets the images and reports afterward.

Questions worth asking

• Was contrast actually given? A lumbar CT without dye is a separate, lower-priced code, and the without-contrast version is the far more common study.
• If this was a CT myelogram, ask for all four pieces: the injection procedure, the contrast, the CT itself, and any observation time afterward. They can each bill separately.
• If this scan follows recent back surgery, is it included in the surgeon's global post-operative period or billed on its own?
• Would an MRI answer the same question, and how does the price compare here? Ask specifically, because for soft tissue around the spine an MRI is frequently the study the doctor would prefer.