Radiology with Dr. Gupta
Radiologists are medical doctors (MD) that specialize in diagnosing injuries and diseases using medical imaging (radiology) and procedures (exam/test) such as x-rays, computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, position emission tomography (PET), and ultrasounds. Radiologists complete at least 13 years of training, including medical school, a five year residency, and most often, an additional one-two year fellowship of very specialized training, such as pediatric radiology, musculoskeletal imaging, nuclear medicine, and interventional radiology. Then, they are certified by the American Board of Radiology. Fluorscopy and aniography are special application of x-ray imaging, in which a fluorescent screen and image intensifier tube is connected to a closed-circuit television system. This allows real-time imaging of structures in motion or augmented with a radiocontrast agent. Radiocontrast agents are usually administered by swallowing or injecting to delineate anatomy and functioning of the blood vessels, the GI tract or GU system. The first commercially viable CT scanner was invented by Sir Godfrey Hounsfield at EMI Central Research Labs, Great Britain in 1972. CT imaging uses x-rays in conjuction with computing algorithms to image the body. In CT, an x-ray tube opposite of an x-ray detector (or detectors), in a ring-shaped apparatus rotate around a patient, producing a computer-generated cross-sectional image (tomogram). CT is acquired in the axial plane, with coronal and sagittal images produced by computer reconstruction. Ultrasonography use ultrasound (high-frequency sound waves) to visualize soft tissue structures in the body in real time. No ionizing radiation is involved, but the quality of the images obtained using ultrasound is highly dependent on the skill of the person (ultrasonographer) performing the exam and patient body habitus. Ultrasound is also limited by its inability to image through air (lungs, and bowel loops) or bone. Because ultrasound does not use ionizing radiation it is the modality of choice in obstetrical imaging. Color-flow Doppler ultrasound measures the severity of peripheral vascular disease and deep vein thrombosis. Small, portable ultrasound devices now replace peritoneal lavage in the triage of trauma. MRI uses strong magnetic fields to align atomic nuclei (usually hydrogen protons) within the body tissues, then uses a radio signal to disturb the axis of rotation of the nuclei and observes the radio frequency signal generated as the nuclei return to their baseline states. The radio signals are collected by small antennae, called coils, placed near the area of interest. An advantage of MRI is its ability to produce images in multiple oblique planes with equal ease. MRI scans give the best soft tissue contrast of all imaging modalities and has become an important tool in musculoskeletal radiology and neuroradiology.
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