Medical imaging has become a crucial part of modern medicine. The utilization of computers has emerged as a promising technique in the fields of medical imaging and image analysis. The generation of an accurate and reliable result necessitates the implementation of an effective algorithm and effective methods at each level of analysis. Various modalities, including Magnetic resonance imaging (MRI), X-ray, Computed tomography (CT), and Ultrasound, are employed for therapeutic and diagnostic reasons. These modalities provide the most comprehensive information possible about the patient. The most common methods of analyzing medical images are image enhancement, segmentation, quantification, and registration. This Chapter offers an introduction to the fundamental principles and concepts that are integral to the fundamentals of medical image analysis. Additionally, the chapter addresses numerous challenges associated with medical image analysis and suggestions for future research directions. This Chapter will enable researchers to understand better the current status, challenges, and future directions of this energetic research field.