Lecture 1: Discovery of X-Rays & Fundamental Principles
Our journey begins with the discovery of X-rays by Wilhelm Röntgen and the revolutionary impact it had on medical imaging. We explore the basic physics of X-ray production and the factors (kVp, mAs) that control image quality, laying a strong foundation for understanding the fundamental principles of radiology.
we continue our journey into achieving optimal image formation, starting with the challenge that the human eye and display screens cannot distinguish all 2000+ Hounsfield Unit (HU) differences in a CT scan. This challenge is addressed through CT windowing (WW/WL), which allows us to select the tissue of interest—such as brain, bone, soft tissue, or lung—and map its HU values into visible grayscale. Finally, we demonstrate how these techniques are applied to real-life clinical cases encountered in daily practice.
Continuing our journey, we trace the evolution of CT scanners from the first to the seventh generation, highlighting the improvements in speed, image quality, and clinical capabilities at each stage. We explore why each new generation was developed and how it differs from the previous one, while introducing key concepts and innovations, such as helical vs. axial scanning and multidetector vs. multislice technology, that have significantly enhanced scanning efficiency and diagnostic performance.
Building on our introduction to scan types, we explore the practical applications of the scanogram, including estimating patient radiation dose, positioning, and its effect on image quality. We then dive into axial scans, understanding their principle, use cases, and the types of examinations suited for this method. Finally, we cover helical scans, highlighting their principles, applications, and advantages in clinical practice.
Lecture 8: CT Parameters – Slice Thickness & Rotation Time
Continuing with CT scanning, we focus on key parameters like slice thickness and rotation time, understanding their effect on image clarity and scanning efficiency.
Continuing our exploration of CT parameters, we focus on Field of View (FOV) and its influence on image resolution and coverage. We also introduce the important distinction between Scan FOV and Display FOV, and how each one affects image acquisition and visualization, linking these concepts to other scanning parameters for optimal imaging.
Continuing our journey, we focus on image reconstruction, converting HU values into high-quality diagnostic images, and understanding how raw data is transformed into usable image data. We also explore the key concepts of image quality, including voxel vs. pixel, spatial resolution, and signal-to-noise ratio (SNR), and how these factors influence the final image.
Finally, we explore advanced reconstruction and display techniques, starting with Multiplanar Reconstruction (MPR), which includes reconstructed images on different planes, such as the Axial, Coronal, Sagittal, and Oblique planes. We then cover Curved MPR, Maximum Intensity Projection (MIP), Minimum Intensity Projection (MinIP), and 3D techniques such as Volume Rendering and Virtual Endoscopy. The lecture also discusses the role of filter functions (reconstruction kernels), how to select them appropriately, and how these techniques can be applied to real clinical cases in daily practice.