High-Resolution Computed Tomography (HRCT) has emerged as an indispensable tool in diagnosing and managing various pulmonary diseases. Since its inception in the 1970s, HRCT has undergone significant advancements, particularly with the advent of MultiDetector CT (MDCT) scanners. This abstract aims to provide a comprehensive overview of HRCT, focusing on its principles, techniques, and applications. The fundamental principle underlying HRCT lies in its ability to acquire thin-section CT images with high spatial resolution, enabling the detection and characterization of diseases affecting the lung parenchyma and airways. Unlike conventional radiography, HRCT offers cross-sectional images without superimposition of structures, thus providing clearer visualization of abnormalities. Additionally, HRCT exhibits superior sensitivity to subtle differences in X-ray attenuation, making it a preferred modality for pulmonary imaging. MDCT scanners have revolutionized HRCT by allowing the acquisition of volumetric data in a single breath hold. This advancement enables the reconstruction of spaced, contiguous, and overlapping HRCT images, facilitating multi-planar reconstruction and thin-section HRCT evaluation. Moreover, post-processing techniques such as maximum intensity projection (MIP) and minimum intensity projection (minIP) further enhance the diagnostic utility of HRCT. The primary objective of HRCT is to detect, characterize, and determine the extent of diseases involving the lung parenchyma and airways. From fibrotic lung diseases to obstructive conditions, HRCT plays a pivotal role in accurate diagnosis and treatment planning. Quantitative CT, an emerging technique, utilizes standardized protocols for the quantification of lung features, providing valuable insights into disease progression and response to therapy. Historically, HRCT utilized non-contiguous inspiratory thin-section images, albeit with limitations in diagnostic accuracy. However, with the widespread availability of MDCT scanners, HRCT is predominantly performed using isotropic data acquisition, optimizing diagnostic yield while minimizing radiation exposure. In conclusion, HRCT represents a cornerstone in pulmonary imaging, offering unparalleled resolution and diagnostic accuracy. With ongoing technological advancements and standardized protocols, HRCT continues to evolve as an indispensable tool in the diagnosis and management of pulmonary diseases. This abstract provides a comprehensive insight into the principles, techniques, and applications of HRCT, highlighting its pivotal role in modern healthcare practice.