Diagnostic imaging techniques

What lies ahead for the future of medical imaging? InCarestream is pushing the boundaries of engineering innovation in radiology in four important areas:

Diagnostic imaging techniques

Imaging modalities[ edit ] a The results of a CT scan of the head are shown as successive transverse sections.

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Dermatology and wound care are Diagnostic imaging techniques modalities that use visible light imagery. Diagnostic radiography designates the technical aspects of medical imaging and in particular the acquisition of medical images.

The radiographer or radiologic technologist is usually responsible for acquiring medical images of diagnostic quality, although some radiological interventions are performed by radiologists. As a field of scientific investigation, medical imaging constitutes a sub-discipline of biomedical engineeringmedical physics or medicine depending on the context: Research and development in the area of instrumentation, image acquisition e.

Many of the techniques developed for medical imaging also have scientific and industrial applications.

Diagnostic Imaging: MedlinePlus

Radiography Two forms of radiographic images are in use in medical imaging. Projection radiography and fluoroscopy, with the latter being useful for catheter guidance.

These 2D techniques are still in wide use despite the advance of 3D tomography due to the low cost, high resolution, and depending on the application, lower radiation dosages with 2D technique.

This imaging modality utilizes a wide beam of x rays for image acquisition and is the first imaging technique available in modern medicine. Fluoroscopy produces real-time images of internal structures of the body in a similar fashion to radiographybut employs a constant input of x-rays, at a lower dose rate.

Contrast mediasuch as barium, iodine, and air are used to visualize internal organs as they work. Fluoroscopy is also used in image-guided procedures when constant feedback during a procedure is required. An image receptor is required to convert the radiation into an image after it has passed through the area of interest.

Early on this was a fluorescing screen, which gave way to an Image Amplifier IA which was a large vacuum tube that had the receiving end coated with cesium iodideand a mirror at the opposite end. Eventually the mirror was replaced with a TV camera. Projectional radiographsmore commonly known as x-rays, are often used to determine the type and extent of a fracture as well as for detecting pathological changes in the lungs.

With the use of radio-opaque contrast media, such as bariumthey can also be used to visualize the structure of the stomach and intestines - this can help diagnose ulcers or certain types of colon cancer.

Magnetic resonance imaging A brain MRI representation A magnetic resonance imaging instrument MRI scanneror "nuclear magnetic resonance NMR imaging" scanner as it was originally known, uses powerful magnets to polarize and excite hydrogen nuclei i. Radio frequency antennas "RF coils" send the pulse to the area of the body to be examined.

The RF pulse is absorbed by protons, causing their direction with respect to the primary magnetic field to change. When the RF pulse is turned off, the protons "relax" back to alignment with the primary magnet and emit radio-waves in the process.

This radio-frequency emission from the hydrogen-atoms on water is what is detected and reconstructed into an image. The resonant frequency of a spinning magnetic dipole of which protons are one example is called the Larmor frequency and is determined by the strength of the main magnetic field and the chemical environment of the nuclei of interest.

MRI uses three electromagnetic fields: Like CTMRI traditionally creates a two-dimensional image of a thin "slice" of the body and is therefore considered a tomographic imaging technique.

Modern MRI instruments are capable of producing images in the form of 3D blocks, which may be considered a generalization of the single-slice, tomographic, concept.

Unlike CT, MRI does not involve the use of ionizing radiation and is therefore not associated with the same health hazards. For example, because MRI has only been in use since the early s, there are no known long-term effects of exposure to strong static fields this is the subject of some debate; see 'Safety' in MRI and therefore there is no limit to the number of scans to which an individual can be subjected, in contrast with X-ray and CT.

Diagnostic imaging techniques

However, there are well-identified health risks associated with tissue heating from exposure to the RF field and the presence of implanted devices in the body, such as pacemakers. These risks are strictly controlled as part of the design of the instrument and the scanning protocols used.

Because CT and MRI are sensitive to different tissue properties, the appearances of the images obtained with the two techniques differ markedly. In CT, X-rays must be blocked by some form of dense tissue to create an image, so the image quality when looking at soft tissues will be poor.

In MRI, while any nucleus with a net nuclear spin can be used, the proton of the hydrogen atom remains the most widely used, especially in the clinical setting, because it is so ubiquitous and returns a large signal.

This nucleus, present in water molecules, allows the excellent soft-tissue contrast achievable with MRI. It is possible to differentiate tissue characteristics by combining two or more of the following imaging sequences, depending on the information being sought: Different from the typical concept of anatomic radiology, nuclear medicine enables assessment of physiology.Diagnostic Imaging Diagnostic imaging plays a critical role in initial cancer diagnosis, treatment planning, and palliative therapies through interventional techniques and cancer monitoring.

The Department of Radiology offers state-of-the-art clinical care and recently has expanded to enhance its services. A point-of-care imaging system could help reduce risks associated with transporting patients from an intensive care or neurosciences critical care unit to the CT scanner suite.

It could also offer high-quality imaging in the operating room. A radiologist is a doctor who specializes in imaging techniques. He or she is the person who usually reads (interprets) the images made during the test.

The radiologist writes a report on the findings and sends the report to your doctor.

Information

Numerous diagnostic imaging techniques may be used to supplement history, physical examination, and laboratory tests in the evaluation of bone and joint disease.

The choice of the imaging techniques to use and in what sequence depends on the sensitivity and specificity of the technique for a. X-ray based methods of medical imaging include conventional X-ray, computed tomography (CT) and mammography.

To enhance the X-ray image, Diagnostic ultrasound systems use high-frequency sound waves to produce images of soft tissue and internal body organs. Imaging using X-rays. Diagnostic Imaging Techniques of the Foot and Ankle Imran M.

Omar Diagnostic imaging of the foot and ankle has made numerous advancements in the last 25 to 30 years and allows rapid, noninvasive, high-resolution depiction of anatomy and pathology.

Medical imaging - Wikipedia