B42F0ZZ
Computerized Tomography (CT Scan) Lower Extremity Arteries, Right to None with None, High Osmolar Approach
Procedural Specifications
| Clinical Axis | Detail Definition |
|---|---|
| Section | B Imaging |
| Body System | 4 Lower Arteries |
| Operation | 2 Computerized Tomography (CT Scan) |
| Body Part | F Lower Extremity Arteries, Right |
| Approach | 0 High Osmolar |
| Device | Z None |
| 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 CT scanning of the arteries below the diaphragm, most often the abdominal aorta and its branches, the renal arteries, and the iliac and femoral vessels. Multiple X-ray exposures are taken from different angles and reassembled by computer into detailed cross-sectional and three-dimensional images, frequently after an intravenous contrast injection that highlights the arterial lumen, a technique commonly referred to as CT angiography.
Physicians rely on this imaging to detect aneurysms, dissections, blockages, or abnormal narrowing in the lower body's arterial supply, particularly when planning surgery or a minimally invasive repair. It has become a preferred method for evaluating these vessels because it produces highly detailed images relatively quickly and can be reviewed from virtually any angle after the scan.
Anatomy & Axis Detail
Lower Extremity Arteries, Right
The right lower extremity arterial system extends from the external iliac artery through the common femoral, superficial femoral, popliteal, and tibial vessels to the foot. CT angiography of this limb is used to characterize peripheral arterial disease, map occlusions and collateral flow in patients with claudication or critical limb ischemia, and plan revascularization by surgery or endovascular intervention. Because the run-off vessels below the knee are small in caliber and prone to calcification, image acquisition and post-processing must account for both, since dense calcific plaque can obscure the true lumen on standard windowing and often requires bone-subtraction or curved reformatting to assess accurately. As with the left limb, laterality is coded separately, so right-sided findings should not be conflated with the contralateral leg.
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.
Coding & Documentation
A code from this family requires the report to confirm the study was performed by CT, name the specific lower artery or vascular territory scanned, and indicate whether contrast material was administered, since the qualifier for contrast use directly affects code assignment. Coders should watch for studies that combine multiple contiguous body parts into a single described territory versus separately named vessels, which can change which body part value applies. A common mistake is defaulting to an unspecified abdominal code when the physician's report actually specifies distinct vessels such as the renal or iliac arteries individually.
Commonly Confused With
This family is most often confused with MRI angiography of the same vessels, distinguished by whether the modality section of the report describes ionizing radiation and multiple exposures versus a magnetic field and radiofrequency signals. It also differs from fluoroscopic angiography, which shows live continuous imaging typically tied to a catheter-based procedure rather than a reconstructed set of cross-sectional images, and from plain radiography, which yields only a single flat exposure without the layered detail a CT scan provides.