From the Guidelines
To distinguish angiogram views, it is essential to understand the standard projections and their anatomical relationships, with a focus on the double oblique method, which corrects the oblique course of the ascending aorta and accounts for aortic tortuosity, as recommended in guideline statements 1. When interpreting angiogram views, it is crucial to consider the advantages and disadvantages of different imaging modalities, such as computed tomography angiography (CTA), which offers a comprehensive assessment of the entire aorta and branch vessels, but may have limitations in characterizing active inflammation and carries the risk of iodinated contrast nephropathy and ionizing radiation 1. The main angiographic views include:
- Anteroposterior (AP)
- Lateral
- Right anterior oblique (RAO)
- Left anterior oblique (LAO)
- Cranial
- Caudal projections Each view provides unique visualization of different coronary artery segments, and understanding how three-dimensional coronary anatomy translates to two-dimensional projections is vital for accurate interpretation. It is also important to recognize the potential drawbacks of arteriography, including its invasive nature and the known complications from catheterization, and to consider alternative imaging modalities, such as ultrasound (US), MR angiography (MRA), or CT angiography (CTA), which can accurately triage patients with confirmed peripheral arterial disease for percutaneous or surgical treatments 1. In clinical practice, the double oblique method is the standardized approach recommended for distinguishing angiogram views, as it provides a reliable and accurate depiction of the aortic anatomy, which is essential for diagnosis and treatment planning 1.
From the Research
Distinguishing Angiogram Views
To distinguish angiogram views, it is essential to consider the type of contrast agent used, as well as the specific characteristics of the angiography procedure.
- The choice of contrast agent, such as iodixanol or iohexol, can affect the quality of the angiogram images 2, 3, 4, 5, 6.
- Iodixanol, an iso-osmolar non-ionic dimeric hydrophilic contrast agent, has been shown to have fewer side effects and similar image quality compared to low-osmolar contrast media 4.
- In cerebral angiography, the use of low-concentration iodinated contrast agents, such as iohexol 240 mgI/mL, iopamidol 250 mgI/mL, and iodixanol 270 mgI/mL, has been found to provide image quality comparable to that of conventional high-concentration agents, with no significant increase in adverse events 6.
- The evaluation of image quality is typically performed using a scale, such as a 4-level scale, by independent, blinded radiologists 6.
- Adverse reactions to contrast agents can be monitored both immediately and up to 7 days post-procedure, and the overall safety profile can be assessed by analyzing vital signs, electrocardiogram readings, and other relevant factors 6.
Contrast Agent Characteristics
The characteristics of the contrast agent used can also impact the distinction of angiogram views.
- Iodixanol has a higher viscosity than monomeric agents, which can affect its use in certain procedures 4.
- The osmolality of the contrast agent, such as iodixanol's iso-osmotic properties, can influence its safety and efficacy profile 2, 3, 5.
- The concentration of the contrast agent, such as low-concentration iodinated contrast agents, can also impact the quality of the angiogram images and the safety profile of the procedure 6.