Archive for the 'Medical Imaging' Category
April 12th, 2007 by misvan
My earlier post on the Pernkopf Anatomy Atlas discussed the ethical implications associated with the source of cadavers for use in medical education. And while I mentioned that medical history is spotted with such ethical controversies, modern day medical and anatomical resources aren’t without scrutiny.
The Visible Human Project, established in 1989, set out to complete a full digital library representing the anatomy of a normal adult male and female. The Visible Human Male was completed in 1994 and the Visible Human Female completed the following year. While you can find this information and more on the The Visible Human Project website, what they don’t mention is where the male and female bodies came from.
The Visible Human Male was a mechanic from Texas, named Joseph Paul Jernigan. On July 3, 1981 he stabbed and shot a 75-year-old man, who surprised him during a robbery. Jernigan was convicted of murder and sentenced to death on November 20, 1981. He was finally executed, by lethal injection, 12 years later on August 5, 1993. Before his execution a prison chaplain convinced Jernigan to donate his body to the Texas Anatomy Board. Jernigan had no idea that his body would become part of one of the most important anatomy resources of the 20th century; the first completely digitized human being.
The U.S. National Library of Medicine (NLM) organized the Visible Human Project. Cadavers for the project were selected from people who had donated their bodies to medical research. Soon after death MRI and CT scans were performed on these bodies, which were then frozen in gelatin. A selected committee from the NLM then reviewed the MRI and CT scans and chose the best cadaver representing the most normal anatomy, proportion, height, and weight of a male and female. The committee subsequently chose Jernigan’s body without knowing that he was an executed prisoner convicted of murder. But, the committee decided that since Jernigan had donated his body to science, there were no ethical implications against his body becoming part of the project.
So, should we judge the use of Jernigan’s body for the Visible Human Project? Would the committee have chosen Jernigan if they would have known that he was an executed prisoner convicted of murder? What are your thoughts?
February 26th, 2007 by misvan
Warning: the following videos are graphic!
Click on these links to view the videos
Recluse spider bite
Healing frostbite
Digital image morphing of a bite from a brown recluse spider, progressing from a minor wound to an extensive necrosis of the skin and underlying soft tissues.
Successful healing of frostbite on the fingers.
You’ve probably seen digital image morphing before, either in commercials or in the movies. Hollywood has used digital image morphing for years now to turn humans into animals, humans into other humans, or to simulate aging. Now a paper by Keith Penska, Les Folio, and Rolf Bunger, entitled ‘Medical Applications of Digital Image Morphing’ in the Journal of Digital Imaging (2007), introduces digital image morphing to medicine.
Digital image morphing is a process by which one image transforms into another image through a series of generated intermediate steps. This is performed through a program that generates a smoothing algorithm that makes the final video seem to blend slowly from the initial image into the final one.
All you need to create an image morph is readily available software (just search for image morphing software on Google) and an average computer or laptop. To ensure a good image morph you do need to make sure images are of equal size and properly registered with each other. This will create a smooth transition. Also, make sure the backgrounds are the same. You can tell in the above videos that the images weren’t completely registered.
Digital image morphing has potential medical applications, especially for primary care physicians and their patients. It provides a quick and cost-effective way to show patients how their treatment has progressed over a period of time, or how their disease has progressed over time. And this doesn’t just apply to diseases or injuries on the surface of the skin. Image morphing can be performed with x-ray’s and even with MRI and CT scans. Plastic surgeons can use image morphing as a sort of digital portfolio to show before and after transitions. Image morphing provides a more dramatic effect than viewing two separate images of a before and after.
However, there are limitations. According to the journal article mentioned above, “ the smoothing process is synthetic and based on information from each of the images’ control points to reflect the blending of the images as the movie is created.†Basically this is saying the images in between the original images are not real, they are only an approximation. Obviously, the more images you have in the sequence, the more accurate the representation.
I’d like to hear what you think. Is this a good idea? Would doctors use this technology to educate their patients?
February 22nd, 2007 by misvan
In one of my last posts, I introduced the relatively new process of using MRI and CT scanning to perform virtual autopsies. Here I present a case where virtual autopsy was used to determine the cause of death of an unfortunate swimmer who was run over by a steamboat bucketwheel. Take a good look at fig 3 and you will instantly see the severity of the wounds inflicted on the body.
Case: A 53 year-old male swimmer was struck by the buckwheel of a steamboat in a local lake (fig 1). He suffered blunt trauma and sank. Divers found his body 5 days later at a depth of 18m.
fig 1
Virtual Autopsy: ‘The body was wrapped in two radiological artifact free body bags to preserve anonymity and to prevent contamination of the radiological equipment.’
First, a multi-slice computed tomography (MSCT) scan was performed on the body. This revealed comminuted fractures of the 8-10th thoracic vertebrae (fig 2). There were also fractures of the spinous processes of the 5, 8-11th thoracic vertebrae. The right shoulder was completely dislocated ventrally from the glenoid fossa (fig 3). Ouch. Fluid was found in the stomach, duodenum, trachea, and paranasal cavities. Both lungs were over inflated.
fig 2
fig 3
Next, an MRI was performed which revealed a complete rupture of the descending aorta at the level of the fractured 8-10th thoracic vertebrae (fig 4,5). A huge haematothorax was detected in the left thoracic cavity (fig 5 HT).
fig 4
fig 5
Generally, a complete rupture of the aorta will result in death due to fatal hemorrhaging at the site of the rupture.
Physical Autopsy: Confirmed all of the findings from the MSCT and MRI scans.
Cause of Death: A combination of fatal hemorrhage, caused by aortic rupture, and drowning.
The study concluced that “virtual autopsy using combined post-mortem MSCT and MRI is a useful tool for documentation, visualization and analysis of the findings of blunt force trauma and drowning with a large potential in forensic medicine.”
Source
Aghayev, E., Thali, M., Sonnenscein, M., Hurlimann, J., Jackowski, C., Kilchoer, T., & Dirnhofer, R. (2003) Fatal steamer accident; blunt force injuries and drowning in post-mortem MSCT and MRI. Forensic Science International. 152: 65-71.
February 20th, 2007 by misvan
[Article via Herald Sun]
MELBOURNE surgeons have miraculously saved a teenager who was speared through an eye with a metal chair leg.
Shafique el-Fahkri, 19, was admitted to Royal Melbourne Hospital with the chair leg embedded about 10cm through his head to his neck, where it had partially severed an artery.
He walked out of hospital on Friday, 19 days after being admitted, with no brain damage or loss of sight.
The horrific injury was sustained in a brawl in the city outside Metro nightclub in Bourke St. Fireman cut the chair away from Mr el-Fahkri’s head at the scene.
Doctors told the Northcote teen’s father, Moses el-Fahkri, they were astonished the youth had survived.
Read the rest of the article here
February 20th, 2007 by misvan
CT and MRI scans are typically used for diagnostic purposes and there are numerous programs (e.g. Osirix) out there dedicated to computing the data from these scans and turning it into interactive 3D images. But, if CT and MRI scans can be used on the living, why not use them on the deceased? It just so happens that the winner of the 2006 Science and Engineering Visualization Challenge used a high-resolution CT scanner to generate 2D scans of a 2000 year old mummy that were used to create a 3D model of the mummy and its interior. From the scan researchers were able to reveal that the mummy contained the remains of a 4 or 5-year-old girl who had no signs of trauma or long-term disease. They suspected that she must have died unexpectedly, probably from an infectious disease.
Virtual autopsies are starting to be used as a precursor to the physical kind. The Pentagon has already used this technology on the remains of soldiers who died in Iraq and Afghanistan to determine the effectiveness of helmets and body armor for protection. Forensic investigators in Sweden and Switzerland have performed numerous virtual autopsies on murder victims and are working to perfect the technique. Medical examiners from all over the world, including the U.S. have taken interest.
The benefit of using CT and MRI to create full-body scans of the deceased is that it is non-invasive. Full-body 3D images generated from the scans can be easily be manipulated by zooming in, cropping, and rotating in any direction, something not possible by physical autopsy. In murder victims, bullet paths can instantly be found and the extent of knife wounds easily visualized. This would normally take hours through physical autopsy.
Another benefit of using virtual autopsy, or Virtopsy, is the permanency of the data. Physical autopsies need to be performed soon after death to get an accurate evaluation of the cause of death. With virtual autopsy scans can be performed quickly and the data would be there to be used weeks, months, or even years later. And the data can provide powerful evidence in the courtroom without using graphic images from the real body.
Knife wound to the heart: autopsy and MRI finding
Virtual autopsy can also be used in cultures where physical autopsy is not permitted by custom or religion. Since virtual autopsy does not mutilate the body in any way, the body can be preserved in its natural state.
What about cost? Powerful imaging equipment can be extremely costly, but while traditional autopsies cost an average of $4,000 each, virtual autopsies cost around $1,000 each. This means that virtual autopsies can actually cut the cost of autopsies and ease the financial burden on hospitals and families.
Researchers in this area predict that within the next 10 to 20 years, physical autopsies will be replaced by the virtual autopsy.
The pace at which medical imaging is advancing is incredible. The impact of this type of medical imaging on medical illustration will result in the most accurate illustrations and animations ever created. Because of this, future generations are going to have the benefit of having the most complete understanding of the human body.
Sources and further reading
Virtual autopsies offer help in divining death.
Autopsies, no scalpel required.
Medical experts gather in Australia to eye 3D future of post-mortems.
Virtual autopsy may be next innovation in forensic field.
Images via RSNA
