B42G1ZZ
Computerized Tomography (CT Scan) Lower Extremity Arteries, Left to None with None, Low Osmolar Approach
Procedural Specifications
| Clinical Axis | Detail Definition |
|---|---|
| Section | B Imaging |
| Body System | 4 Lower Arteries |
| Operation | 2 Computerized Tomography (CT Scan) |
| Body Part | G Lower Extremity Arteries, Left |
| Approach | 1 Low 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, Left
CT imaging of the left lower extremity arteries traces the vascular supply from the external iliac artery down through the femoral, popliteal, and tibial segments to the pedal arch. This study is ordered for the same indications as the right leg - claudication, rest pain, non-healing ulcers, or acute limb ischemia - but is coded and reported as a distinct body part because disease severity and prior interventions frequently differ between the two limbs. Contrast bolus timing must accommodate the long distance the dye travels from injection site to the foot, and calcified plaque in the tibial vessels can require dedicated reformatting to distinguish from luminal contrast. Findings are typically described segment by segment to support decisions about the level and type of revascularization.
Contrast: Low Osmolar
Low Osmolar denotes use of a low-osmolar iodinated contrast agent during an imaging study, the class most commonly used in modern radiographic and CT imaging because it better approximates the osmolality of blood and carries a lower risk of reaction than High Osmolar media. This value distinguishes studies performed with this now-standard contrast type from those using older high-osmolar agents or no contrast at all.
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.