Cardiac contour, in the context of medical imaging, refers to the outline or boundary of the heart and its internal structures as visualized on medical images. Specifically, it involves delineating structures like the myocardium (heart muscle), left and right ventricles (LV & RV), and left and right atria (LA & RA).
Importance of Cardiac Contouring
Cardiac image contouring serves as a crucial first step in several diagnostic and treatment planning processes:
- Diagnosis: Accurate contouring allows for the identification of abnormalities in the size, shape, and function of the heart and its chambers.
- Radiotherapy Planning: In cases where radiation therapy is required for conditions affecting the heart or nearby structures, precise contouring ensures accurate targeting of radiation while minimizing damage to healthy tissue.
- Quantitative Analysis: By delineating the heart's structures, clinicians can extract quantitative metrics. These metrics help assess cardiac function and track changes over time. For example, the volume of the left ventricle can be measured to assess its pumping capacity.
Structures Typically Contoured
The specific structures contoured in cardiac imaging depend on the clinical context and the information required. Common structures include:
- Myocardium: The heart muscle itself.
- Left Ventricle (LV): The main pumping chamber of the heart.
- Right Ventricle (RV): Pumps blood to the lungs.
- Left Atrium (LA): Receives oxygenated blood from the lungs.
- Right Atrium (RA): Receives deoxygenated blood from the body.
Techniques for Cardiac Contouring
Cardiac contouring can be performed manually, semi-automatically, or automatically using specialized software. The choice of method depends on factors such as image quality, clinical requirements, and available resources.
- Manual contouring: Requires a trained clinician to manually trace the boundaries of the heart structures on each image.
- Semi-automatic contouring: Involves the user providing initial points or regions of interest, and the software then automatically refines the contours.
- Automatic contouring: Uses algorithms to automatically detect and delineate the heart structures.
