ABSTRACT
Precise diagnosis as early as possible after disease establishment is pivotal for effective therapeutic intervention. The location, nature and molecular mechanism underlying the aberration also need to be explored specifically for accurate drug targeting and predicting the prognosis of the disease. Diagnosis from phenotypic manifestation often delays the onset of treatment and is also lacking in penetration at cellular or sub-cellular level to extract disease-associated molecular information. Diagnostic imaging through various state-of-the-art modalities possesses the capability to acquire signals from several patho-physiological aberrations and present them in an interpretable manner. The penetration level varies according to the employed modality which has to be selected depending upon the availability and requirement. Various forms of physical energies are exploited in different imaging modalities. For instance, visible light is the energy source in optical microscopy, X-ray is employed in radiographic examination, sound waves are used in ultrasonography, magnetic energy is exploited in magnetic resonance imaging (MRI) etc. Initially, diagnostic imaging was intended to amplify a target specimen and arguably the journey began with the introduction of the simple light microscope, which prospered in a multi-directional manner to derive several branches of microscopy, including various optical microscopy techniques, electron microscopy, scanning probe microscopy; radiographic imaging, infra-red-based thermal imaging, ultrasonography, MRI, CT scanning, radiolabeling-based nuclear imaging and tomographic methods, electrical impedance imaging, digital stethoscopy etc. Persistent progress in instrumentation, analytical programs and contrast agents has increased the penetration and resolution of the imaging modalities to explore even the cellular and sub-cellular information regarding disease establishment and progression toward targeted therapeutic intervention. Diagnostic imaging already holds a pivotal position in human medicine and is growing in importance in animal disease diagnosis too. Some major bottlenecks, such as bulky and static instrumentation, the need for skilled technicians, heavy resource involvement, the dearth of devoted animal-specific design in instrumentation and poor dedicated animal databases, need to be addressed adeptly for more commonplace application of these high-end diagnostic imaging modalities in farm-level pen-side animal disease diagnosis.
