Digital Imaging and Communications in Medicine. The international standard (ISO 12052) for storing, transmitting, and managing medical images and related data. A DICOM file contains both the pixel data and a header with patient and acquisition metadata encoded as structured tags.
The imaging technique used to acquire a medical image. Common DICOM modalities include CT (Computed Tomography), MR (Magnetic Resonance), CR (Computed Radiography), DX (Digital X-Ray), US (Ultrasound), PT (Positron Emission Tomography), MG (Mammography), and NM (Nuclear Medicine). Stored in DICOM tag (0008,0060).
Parameters that define the mapping of Hounsfield Unit (HU) values to display brightness. Window Width (WW) sets the visible HU range; Window Center (WC) sets the midpoint of that range. Also called window/level. Example: Brain window uses WW 80, WC 40; Bone window uses WW 1500, WC 300.
The process of selecting a subset of the full Hounsfield Unit range for display by adjusting WW and WC. Narrowing the window makes specific tissue types (bone, soft tissue, lung) optimally visible. Essential for diagnostic CT interpretation and also applied to MRI signal intensity.
The quantitative scale used in CT imaging to express radiodensity relative to water (0 HU) and air (−1000 HU). Dense bone is approximately +1000 HU; fat is around −100 HU; soft tissue falls between +20 and +80 HU. Named after Sir Godfrey Hounsfield, co-inventor of the CT scanner.
A post-processing technique that resamples a volumetric CT or MRI DICOM series to generate image planes other than the original acquisition plane. MPR produces axial, coronal, and sagittal views and can generate oblique planes. Requires a series with isotropic or near-isotropic voxel spacing.
A group of related DICOM images acquired in a single continuous sequence within one Study. All images in a Series share a Series Instance UID (0020,000E) and typically represent the same anatomical region acquired with the same modality settings. A single Study may contain multiple Series (e.g., pre- and post-contrast CT phases).
A clinical examination event that produces one or more DICOM Series. All Series in a Study share a Study Instance UID (0020,000D) and are associated with the same patient encounter, order, and date. In a PACS, the Study is the primary organisational unit for managing a patient's imaging examination.
Metadata elements in a DICOM file encoded as (Group, Element) pairs in hexadecimal notation — for example (0010,0010) for Patient Name or (0008,0060) for Modality. Tags carry patient demographics, acquisition parameters, and image properties. Each tag has a defined Value Representation (VR) such as PN (Person Name), CS (Code String), or DS (Decimal String).
Picture Archiving and Communication System. A medical imaging technology providing storage, retrieval, management, distribution, and presentation of DICOM images. A PACS consists of a server archive, a worklist broker, and client viewers communicating via the DICOM protocol. Web-based DICOM viewers complement PACS by enabling browser access without dedicated workstation software.
The removal or replacement of patient-identifiable information from DICOM tags to protect privacy before sharing images for research, education, or consultation. The DICOM standard defines a de-identification profile in PS 3.15. Commonly removed tags include Patient Name (0010,0010), Patient ID (0010,0020), Date of Birth (0010,0030), and Accession Number (0008,0050).