B52G00Z
Computerized Tomography (CT Scan) Pelvic (Iliac) Veins, Left to None with Unenhanced and Enhanced, High Osmolar Approach
Procedural Specifications
| Clinical Axis | Detail Definition |
|---|---|
| Section | B Imaging |
| Body System | 5 Veins |
| Operation | 2 Computerized Tomography (CT Scan) |
| Body Part | G Pelvic (Iliac) Veins, Left |
| Approach | 0 High Osmolar |
| Device | 0 Unenhanced and Enhanced |
| Qualifier | Z None |
Operation Definition
Computer reformatted digital display of multiplanar images developed from the capture of multiple exposures of external ionizing radiation
Procedure Overview
This family covers computed tomography imaging of the venous system, in which a scanner rotates around the patient capturing many individual X-ray exposures that a computer reconstructs into detailed cross-sectional and three-dimensional images. Known clinically as CT venography, it is typically performed after an intravenous injection of iodinated contrast timed to opacify the veins of interest, whether in the legs, pelvis, abdomen, chest, or neck.
Physicians order it to detect deep vein thrombosis, particularly in body regions that are hard to evaluate with ultrasound such as the pelvic or abdominal veins, to investigate suspected venous compression syndromes, or to map venous anatomy before surgery or a device placement. Its ability to produce fast, high-resolution images across a large body region makes it especially useful in urgent evaluations and in patients whose body habitus limits ultrasound quality.
Anatomy & Axis Detail
Pelvic (Iliac) Veins, Left
The left pelvic, or iliac, veins return blood from the left lower extremity and pelvic viscera toward the inferior vena cava, passing beneath the left common iliac artery in a location predisposed to extrinsic compression. CT of this venous segment is frequently indicated when clinicians suspect left-sided iliofemoral deep vein thrombosis, particularly in the setting of May-Thurner syndrome, where the overlying right iliac artery narrows the left vein against the underlying vertebral body. The study also helps delineate venous involvement by pelvic tumors, lymphadenopathy, or post-surgical changes. Because laterality determines the correct code, the report must clearly identify the left side, and venous-phase contrast timing is used to distinguish thrombus from the slow, sometimes turbulent flow normally seen in this vessel.
Contrast: High Osmolar
High Osmolar identifies imaging studies performed using a high-osmolar iodinated contrast agent, an older class of media with osmolality well above that of blood plasma. These agents carry a comparatively higher risk of adverse reactions and are used less often today than Low Osmolar agents, which produce similar radiographic enhancement with better patient tolerance. The value simply records which contrast class, if any, was administered for the study.
Qualifier: Unenhanced and Enhanced
Unenhanced and Enhanced specifies that an imaging study was performed both before and after administration of contrast material, allowing comparison between the two phases. This is common in studies evaluating enhancement patterns of lesions, such as certain CT or MRI protocols. It differs from None, which reflects a purely unenhanced study, and from single-agent contrast qualifiers used elsewhere.
Coding & Documentation
Accurate coding depends on the report clearly naming the venous structure or region examined, since the body part value is vessel-specific and studies covering multiple regions, such as combined pelvic and lower extremity venography, may require more than one code. Coders must confirm from the documentation whether contrast was administered and select the qualifier accordingly, and should watch for reports that describe a combined CT arteriogram and venogram performed in one session, which requires separate codes for the arterial and venous components rather than a single entry. Another pitfall is coding a CT scan that only incidentally shows a vein, rather than one performed specifically to evaluate venous anatomy, as a dedicated venography study.