Clinical Veterinary Radiology: The branch of veterinary medicine that uses diagnostic imaging techniques—such as radiography, ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear imaging—to visualize and assess anatomical structures, physiological functions, and pathological conditions in animals. It involves the application of ionizing (e.g., X-rays) and non-ionizing (e.g., ultrasound, MRI) radiation to create detailed images of bones, organs, soft tissues, and other structures, aiding in the diagnosis, treatment planning, and monitoring of diseases in species ranging from companion animals to large animals and exotics. The glossary of clinical vet radiology (A to Z) encompasses image acquisition, interpretation, and integration with clinical findings, adhering to radiation safety principles and standardized protocols for surgery.
Terminology
Below is a comprehensive glossary of terminology related to clinical veterinary radiology, organized alphabetically from A to Z. This glossary covers key terms used in veterinary diagnostic imaging, focusing on radiography, ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), nuclear imaging, and related concepts. Each term includes a brief definition tailored to its use in veterinary radiology.
A
- ALARA (As Low As Reasonably Achievable): A radiation safety principle to minimize radiation exposure to veterinary personnel and patients while maintaining diagnostic image quality.
- Absorption: The process by which X-rays are attenuated (absorbed or scattered) by tissues, contributing to the formation of a radiographic image.
- Anatomic Directional Terms: Standardized terms (e.g., cranial, caudal, rostral, dorsal, ventral) used to describe the orientation of body parts in veterinary radiology, as defined by the Nomina Anatomica Veterinaria.
- Angiography: A radiographic technique using contrast media to visualize blood vessels, often used to assess vascular abnormalities in animals.
- Arthrography: A radiographic procedure involving the injection of contrast media into a joint to evaluate joint structures, such as cartilage or ligaments.
- Artifact: An unwanted feature in an image (e.g., motion blur, metallic objects) that distorts or obscures diagnostic information.
B
- Barium Study: A contrast radiography technique using barium sulfate to visualize the gastrointestinal tract, such as in esophageal or intestinal studies.
- Beam Divergence: The spreading of the X-ray beam as it travels from the source, affecting image magnification and distortion.
- Bit Depth: The number of gray shades a digital imaging system can record, affecting the contrast resolution of the image.
- Bone Scan: A nuclear medicine procedure using radioisotopes to evaluate bone metabolism, commonly used in horses for detecting lameness.
C
- Collimation: The process of restricting the X-ray beam to a specific area to reduce scatter radiation and improve image quality.
- Computed Radiography (CR): A digital imaging system using photostimulable phosphor plates to capture X-ray images, less common than direct digital radiography (DR).
- Computed Tomography (CT): An imaging modality using X-rays to create detailed, cross-sectional images of the body, useful for complex anatomical assessments.
- Contrast: The difference in radiopacity between tissues, enabling differentiation of structures on a radiograph (e.g., bone vs. soft tissue).
- Contrast Media: Substances (e.g., iodine, barium) used to enhance visibility of specific structures or fluids in radiographic or CT studies.
- Cranial: Refers to the direction toward the head from a given point, used in positioning and image description (e.g., cranial to the carpus).
- Cystography: A radiographic procedure using contrast media to visualize the urinary bladder, often for detecting bladder rupture or masses.
D
- Deviation Index (DI): A logarithmic measure of how the actual exposure index (EI) deviates from the target exposure index (EIT), used to assess exposure quality. DI = 10log10(EI/EIT).
- DICOM (Digital Imaging and Communications in Medicine): A standardized format for medical image storage and transfer, including a hidden header to track image manipulations, ensuring legal integrity.
- Differential Absorption: The varying ability of tissues (e.g., bone, fat, soft tissue) to absorb X-rays, creating contrast in radiographic images.
- Digital Radiography (DR): A modern X-ray imaging system using digital detectors to produce high-resolution images, widely used in veterinary practice.
- Dosimetry Badge: A device worn by veterinary personnel to monitor radiation exposure, ensuring compliance with safety standards.
- Dorsal Longitudinal Plane: The veterinary equivalent of the human coronal plane, used to describe anatomical orientation in imaging.
- Dorsoventral (DV): A radiographic projection where the X-ray beam enters the dorsal surface and exits the ventral surface of the animal.
E
- Echocardiography: An ultrasound technique used to image the heart, assessing cardiac structure and function.
- Exposure Index (EI): A measure of the radiation dose received by the image receptor, used to evaluate exposure settings in digital radiography.
- Exposure Time: The duration of X-ray emission during imaging, a key factor in reducing scatter radiation and ensuring image quality.
F
- Fluoroscopy: A real-time X-ray imaging technique used to visualize dynamic processes, such as swallowing or joint movement.
- Focal Spot: The area on the X-ray tube anode where electrons strike to produce X-rays, affecting image sharpness.
- Fog: Unwanted darkening of a radiographic image due to scatter radiation or improper processing, reducing diagnostic quality.
G
- Grid: A device placed between the patient and the image receptor to reduce scatter radiation, improving image contrast and clarity.
- Gray Scale: The range of gray shades in a digital image, determined by bit depth, affecting the ability to distinguish tissue types.
H
- Hanging Protocol: A standardized method for displaying radiographs (e.g., lateral views with the head to the left) to ensure consistency in interpretation.
- Hounsfield Unit (HU): A quantitative scale used in CT to measure tissue density, aiding in the differentiation of tissue types.
I
- Image Receptor: The device (e.g., film, digital detector) that captures X-rays to form a radiographic image.
- Ionizing Radiation: Radiation (e.g., X-rays, gamma rays) capable of producing ion pairs in matter, used in radiography and CT but requiring safety precautions.
- Interpretation Paradigm: A systematic approach to evaluating radiographs, guiding the radiologist through identification, analysis, and correlation with clinical findings.
- Interventional Radiology: Minimally invasive procedures guided by imaging (e.g., ultrasound-guided biopsies) to diagnose or treat conditions.
J
- Joint Space: The radiolucent area between bones in a joint, assessed for narrowing or widening in conditions like arthritis or luxation.
K
- Kilovoltage Peak (kVp): The peak voltage applied to the X-ray tube, controlling the energy of X-rays and their penetration through tissues.
- Kyphosis: An abnormal curvature of the spine visible on radiographs, often assessed in orthopedic evaluations.
L
- Line Pairs per Millimeter (lp/mm): A measure of spatial resolution in radiographic systems, with a minimum standard of 2.5 lp/mm recommended by the ACVR.
- Localizer Image: A preliminary image (e.g., scout or topogram) used in CT to plan the imaging region, considered a separate series in DICOM studies.
M
- Magnification: The apparent enlargement of structures in a radiograph due to the distance between the object and the image receptor.
- Matrix Size: The grid of pixels (length × width) in a digital image, affecting resolution and detail.
- Milliampere-Seconds (mAs): A measure of X-ray tube current and exposure time, determining the quantity of X-rays produced.
- Magnetic Resonance Imaging (MRI): An imaging modality using magnetic fields and radio waves to produce detailed images of soft tissues, ideal for neurological and musculoskeletal assessments.
- Myelography: A radiographic procedure using contrast media to visualize the spinal cord and nerve roots, often for detecting spinal lesions.
N
- Nonionizing Radiation: Radiation (e.g., ultrasound, MRI) that does not ionize matter, considered safer for patients and personnel.
- Nuclear Imaging: A diagnostic technique using radioisotopes (e.g., technetium-99m) to assess physiological processes, such as bone or thyroid scans.
O
- Opacity: The degree to which a structure blocks X-rays, appearing white on a radiograph (e.g., bone, metal). See Radiopacity.
- Overexposure: Excessive radiation dose in a radiograph, leading to a dark image and potential loss of diagnostic detail.
P
- Pixel: The smallest element of a digital image, contributing to the matrix size and resolution.
- Positioning: The precise placement of an animal for imaging to ensure accurate anatomical representation and diagnostic quality (e.g., lateral recumbency, ventrodorsal).
- Primary Beam: The main X-ray beam emitted from the tube, directed through the patient to the image receptor.
- Projection: The specific orientation of the X-ray beam relative to the patient, named by entry and exit points (e.g., ventrodorsal, lateromedial).
R
- Radiograph: A two-dimensional image produced by X-rays passing through a patient, capturing tissue density variations.
- Radiographic Contrast: The visual difference between structures due to differential X-ray absorption, critical for diagnostic interpretation.
- Radiopacity: The degree to which a structure absorbs X-rays, appearing white or light gray on a radiograph (e.g., bone is more radiopaque than soft tissue).
- Radiolucency: The degree to which a structure allows X-rays to pass through, appearing dark on a radiograph (e.g., gas, air).
- Roentgen Signs: Radiographic findings (e.g., changes in size, shape, opacity) used to identify abnormalities.
- Rostral: Refers to the direction toward the nares (nose) from a point on the head, used in cranial imaging.
S
- Scatter Radiation: X-rays deflected from their original path, contributing to image fog and increased radiation exposure to personnel.
- Scintigraphy: A nuclear imaging technique using gamma cameras to detect radioisotopes, often for bone or thyroid studies.
- Spatial Resolution: The ability of an imaging system to distinguish small details, measured in lp/mm (e.g., 2.5 lp/mm minimum for veterinary radiography).
- Standardized Report: A templated imaging report using consistent terminology, endorsed by organizations like the ACVR for clarity and reliability.
- Sternal-Abdominal Recumbency: A positioning technique where the animal lies on its sternum and abdomen, often used with a horizontal X-ray beam.
T
- Target Exposure Index (EIT): The optimal radiation dose for a specific imaging application, defined by the manufacturer or user based on image quality studies.
- Technique Chart: A guide for selecting exposure settings (kVp, mAs) based on patient size and region, ensuring consistent radiographic quality.
- Teleradiology: The remote transmission of digital images (e.g., DICOM files) to a radiologist for interpretation, enhancing access to specialist expertise.
- Thoracic Radiography: Imaging of the chest to evaluate the lungs, heart, and surrounding structures, often using ventrodorsal and lateral projections.
U
- Ultrasonography: An imaging modality using high-frequency sound waves to visualize soft tissues, organs, and fluids, widely used for abdominal and cardiac assessments.
- Ultrasound-Guided Biopsy: A procedure using ultrasound to guide needle placement for tissue sampling, minimizing invasiveness.
V
- Ventrodorsal (VD): A radiographic projection where the X-ray beam enters the ventral surface and exits the dorsal surface, common for thoracic and abdominal imaging.
X
- X-ray: High-energy electromagnetic radiation used in radiography to penetrate tissues and create diagnostic images.
- X-ray Tube: The device that generates X-rays by accelerating electrons to strike a metal target, producing photons for imaging.
Z
- Zoonotic Disease: A disease transmissible from animals to humans, often noted in radiology reports if imaging findings suggest such conditions (e.g., pulmonary nodules).
