Medical Central: Contrast Mediums

Today, read more on Medical Imaging. This time, we follow something similar to a different section… using special chemicals (called contrast mediums) to see inside the body!

Contrast Mediums

We all know that X-Rays are primarily used for seeing bones. Early X-Rays could only see bones… the rest were shadow, and couldn’t be seen. Soon after X-Rays were released, though, contrast mediums were discovered... somewhere around 1910.

Contrast mediums are radio-opaque liquids. In other words, they’re liquids that X-Rays can’t pass through. They were first tested on cavaders, which is another term for “dead bodies”.  Mercury was one of the first tested, but could only be used on cavaders… since mercury is very poisionous (sp?) to living humans.

Different chemicals (book says elements) started being discovered that could be used. Bismuth was one. In fact, a painkiller called lipidiol (an oily substance, according to the book; book also says accidentally discovered by Jan Sicard, who was French doctor) was discovered to be a good medium contrast, allowing certain machines to see in different places, like the uterus, bladder, and spinal canal (books says the empty area of the spine where the spinal cord is).

Contrast Mediums can be drunk, like radioisotopes substances. But they can also be injected directly into the bloodstream. According to the book, a young German hospital doctor named Werner Forssmann used catheters to inject the contrast (one was foot long!) mediums into cavaders, but wouldn’t be given permission to use on living humans. So he used them on himself! Book says he was reprimanded for this, but was later given a Nobel Prize with two others. He also proved the safety of these things.

Contrast Mediums can be used to see different stuff inside the body. The ones that use this most often are the X-Ray machines and CT scanners, which use X-Rays. But PET Scanners and MRI can benefit from this too. Contrast mediums allow these machines to see bloodstreams, the intestines, spinal canal, and the inside of the heart (coats the inside, so can see holes and stuff if exist). Bloodstreams took a while to find a good contrast medium for, but one was eventually found (one with a familiar term: book says it was iodine), and the first bloodstream X-Ray image (called an "angiogram" in book) was made, and more were able to be made.