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The May/June 2012 CT Edition of the Journal of the American Society of Radiologic Technologists has an excellent article about stroke and CT perfusion. The information outlined is invaluable to any technologist who has to perform perfusion scans. When they started doing them at my former hospital I received very little training on how to do the scan and the post processing. At first I was only told the bare bones of what to do and never told why I was doing it. This "why" component is a necessity for me to understand and learn something properly.
When a patient came in with stroke symptoms it was just as urgent as a trauma. Trying to hurry and do a scan I wasn't completely comfortable with made it even more difficult. I eventually had to seek out staff to educate me on the entire protocol. The post processing is time consuming and requires detailed focus. Again, an understanding of "why" is essential to performing this task correctly. The article discusses how to select a reference artery and vein, which is the first step in the post processing.
The stroke and CT perfusion article discusses the entire process. It has excellent images to demonstrate what the gray scale of the MIPs (maximum intensity projections) should look like. It also shows the color coded perfusion map demonstrating the MTT (mean transit time) or time to drain. It shows the areas that drain the slowest to be in red, yellow, green and finally blue. Blue represents the area in the brain that drains the fastest. Areas that are red indicate infarction while yellow highlights penumbra.
CT perfusion is an effective method for diagnosing acute ischemic stroke. If you do these scans at your hospital make sure you understand each step of the scan and the post processing. Talk to your radiologists and have them discuss with you what they are looking for and how you can improve your work.
This extensive scan may be time consuming but remember you are providing images that can prove to be life saving.
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Imagine for a moment that you are a doctor working in a remote village in South America. You want to quickly and effectively assess a number of patients who are presenting with similar symptoms. Thanks to Aydogan Ozcan and his colleagues at UCLA you can. They have developed rapid diagnostic tests (RDTs) to make this screening process incredibly more efficient.
Blood or other fluid samples are taken and placed on a test strip. Changes in color take place on the strip and diseases like HIV, malaria, or TB can be detected. With the old method, mistakes were made because of human error. With the new technology the test strip is inserted into an attachment that is then inserted into an iPhone or Android based smart phone. The camera phone then takes an image of the strip. This attachment only weighs 65 grams and uses two AAA batteries.
"Software then rapidly reads the digitized RDT image to determine, first, whether the test is valid and, second, whether the results are positive or negative, thus eliminating errors that can occur with a human reader." After this the results are saved and then sent to a global server so the spread of various diseases can be tracked all over the world.
Epidemics can now more quickly be identified and tracked and hopefully treated or prevented.
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I continue to be amazed at the nonconventional uses for CT. This weekend at
Nebraska Medical Center a head scan was done on a 432 pound silverback
gorilla named Tubby. He suffered an upper jaw fracture at the hands of another
larger male gorilla at the Henry Doorly Zoo and Aquarium.
This is only
the third time in the past six years that a zoo animal was transported to a
regular hospital. It took six handlers to log roll Tubby from the stretcher to
the CT table while he was under sedation.
It was determined that no
damage was done to his orbits or sinuses. He did however need surgery
immediately to remove the broken jaw fragments and three teeth.
The
wonderful doctors who helped Tubby said he should make a full recovery in two to
three weeks.
Sometimes when you work in CT you actually get to take part
in monkey business.
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Working in the ER of a level 1 trauma center I worked on a 64 slice CT machine. Other scanners in our other departments throughout the hospital didn't have such a luxury. Toshiba just released an 80 slice machine and it received FDA clearance. It also has the ability to be upgraded to a 160 slice machine if needed. With its high rotation speed data can be acquired very rapidly and scan times are shortened along with faster reconstruction of the images. This in turn will provide faster, safer, and more accurate diagnoses.
Our scanner in the ER had a maximum weight limit of 450 pounds and this new couch has a limit of 660 pounds. A larger gantry bore is necessary for hospitals who treat bariatric patients along with the ever growing size of the average patient. On occasion we had to turn patients away because they exceeded our table's limit. This is both frustrating for the doctor and the patient. The dose reduction technology the new machine offers removes noise from the image with reduced radiation dose. It will also make tests like cardiac exams more efficient and accurate.
This is a necessary addition to the imaging world and it is meeting the expanding clinical needs of the field.
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British researchers have been investigating the use of CT and MRI for post-mortem evaluations. The cause of death can often be determined using one of these great technologies. Grieving families eager to learn how their loved one died sometimes do not want a traditional autopsy performed for cultural or religious reasons. Using one of these radiologic technologies provides an alternative.
The study looked at 182 deceased people in which the cause of death was unknown. "The radiologists' cause of death determination based on CT scans agreed with the more definitive autopsy findings 68% of the time. Conclusions based on MRI were accurate 57% of the time." A CT scan was not helpful in identifying heart problems as the cause of death. However, it was determined that if a CT angiogram of the heart was done after the scan, "...radiologists could pinpoint the cause of death in up to half of all cases, with just a slight error rate..."
Autopsies are still considered the gold standard for cause of death but the supplemental use of CT or MRI has been shown to be useful. Some post-mortem scanning is currently done in Sweden and Australia. It should be noted that as the human body changes in response to death, the images look different from a live scan. Radiologists would need special training to make accurate diagnoses on the deceased. Scanners dedicated to post-mortem evaluations would need to be established. Also, it would need to be determined if licensed technologists would do these scans.
When the opportunity presents itself to see through different eyes, we must open wide and watch the dark "develop" into light.
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Medical imaging plays an important role in solid organ donation and transplantation. Working in CT I saw patients scanned to determine the viability of an organ to be transplanted. I also saw patients scanned prior to surgery who were going to receive a donated organ. Follow up CT scans can also be useful to monitor for signs of infection and organ rejection. The issue of ethics must not be overlooked when discussing transplanted organs. Some people don't agree with this practice while others wait each day for a life saving match.
Medical imaging may be used to make a clinical diagnosis of brain death. CT angiography and perfusion CT have emerged as fast and viable options to determine cerebral blood flow. Both of these exams require the technologist be well trained and understand how to properly perform the detailed reconstructions. Perfusion CT allows for the evaluation of blood perfusion into brain tissues through very small blood vessels.
Imaging applications reach far and wide and harvest hope in many different ways.
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It is estimated that up to 1% of all cancers in the United States can be linked to medical radiation. This means with each x-ray or CT scan the risk increases. A recent study in The Journal of Cancer found a link between dental x-rays and brain tumors called meningiomas. The majority of the tumors are benign but depending upon their location they could cause serious neurological problems.
The average age of the study participants was 57. This means the dental x-rays they received early on were higher in radiation dose. Modern machinery gives off a lower dose. "Four bite wing x-rays are about the same amount of radiation you're exposed to in a typical day: .005 millisieverts," according to the American College of Radiology. A panorex exam also increase the risk. The is the x-ray where the machine moves completely around your head while you stand stationary. It carries about 2x as much radiation as four bite wings. "If study participants had panorex exams when they were younger than 10 years old, their risk of meningioma went up 4.9 times." Again, this speaks to the higher radiation dose from older technology.
Moving to a new city I had to establish with a new dentist. I had a full set of digital x-rays taken and a panorex just last week. I didn't hesitate to do this because my dental health is extremely important to me. I saw another new dentist a couple of years ago and had the same set of pictures taken, again without hesitation. I always make certain to wear the lead shield and make sure my thyroid area is properly covered. Working in this field only increases my exposure to radiation so I must be careful.
One way to tackle this problem is to make a patient's last set of x-rays available to the new treating dentist. With many offices going digital this would seem like a good place to start. Maybe then a whole set of new pictures would not be necessary and the dentist could just x-ray the tooth or teeth causing pain.
With all progress in technology there are downfalls, it just needs to be determined if the benefits outweigh the risks. What is your dental impression?
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This subject matter is near and dear to my heart because my father suffered from lung cancer. He spoke to me about having chest x-rays and nuclear medicine tests but I'm not sure if he ever had a CT scan.
The study shows that "...79% of the cases diagnosed through annual repeat CT scan were detected at clinical Stage 1, the earliest and most treatable stage, compared to only 15% through traditional methods." The importance of identifying cancer early is imperative for a good treatment plan and better patient outcomes.
CT scans continue to show how valuable they are in the diagnosis, screening, and evaluation of many different illnesses.
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A recent article in the Chicago Tribune discusses recent fines that were assessed on a surgical center and two of its nurses for operating x-ray equipment without the proper license. The violations involved a fluoroscope machine. In the state of Illinois and many other states, radiologic equipment must be operated by health professionals licensed under the state Medical Practice Act. This includes but is not limited to certified radiologic technologists (RT), dentists, and veterinarians.
Radiation doses vary depending upon the size of the patient and the length of the exposure. RTs received extensive education and training on the proper exposure techniques used for the patient's body habitus to obtain the best quality image. If someone untrained uses any type x-ray machine, a poor quality image could result in incorrect findings and/or missing information necessary to make an accurate diagnosis. A patient or staff member could also be exposed to higher than necessary radiation levels especially if the proper radiation badges are not worn by the staff.
In this case, no one was hurt or injured. It is vitally important that professionals operate within the scope of their license. It may seem tempting to save time or money to cut corners, but eventually someone may be seriously injured. This risk could never out weigh the possible reward.
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Having worked in an emergency room of a level 1 trauma center I saw my fair share of traumas. Patients were usually in the trauma bay for 5-10 minutes and then immediately brought next door to CT. A new study out of Germany recommends that emergency room doctors wait 30 minutes before ordering CT scans on trauma patients.
If the scan is done right away it can detect severe injuries but the tests could miss other serious problems if done too early. A "pan scan" is typically ordered which includes the head, neck, chest, abdomen and pelvis. The researchers evaluated data collected on 982 patients at a trauma center in Berlin between July of 2006 and November 2008. They found that 37% were diagnosed with multiple traumas and that about 8% of the scans ordered were unnecessary. It was also concluded that in more than 6% of the patients the scans missed injuries that later required surgery or monitoring in the ICU. "We found that single-pass whole-body CT is very effective or specific at determining whether there is injured tissue but is variable in excluding injuries in patients with suspected blunt trauma." The researchers added that negative test results should be confirmed with clinical exams or additional tests to rule out false-negative results.
Trauma patients usually present with a myriad of injuries and need monitoring by experienced trauma doctors and nurses. If they enter the hospital altered or unconscious it may be hours before they can discuss their pain with the physicians so getting the right CT at the right time is imperative.
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The non-traditional applications for CT scan continue to astonish archaeologists and those of us fascinated by this technology. The head of a British man from 100AD was found in 1958 in Salford, England and was preserved in peat bog. He was a murder victim who lived during the Iron Age. Experts have been divided for years about how he died but a new CT scan showed the true cause of death. He was bludgeoned over the head, strangled, and then beheaded.
The scan revealed damage to what remained of the neck was for certain caused by a ligature. The debate continues over why he was killed. Was it a pagan ritual of human sacrifice or punishment for a crime? The 3D image that was reconstructed post-scan clearly shows the severity of the wounds this man sustained.
It is remarkable when something can be used for purposes not initially intended, whether it be a medication, technology, or a tool. It is important to remember that great discoveries can be made looking and living outside the box.
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The applications for CT scans continue to expand. Most recently mummies from Egypt, Peru, Ecuador, and Chile were evaluated with the use of CT technology. The archaeological context of the mummies was unknown. However, it was known that they range from 800 to 5,500 years old and are thus extremely fragile. Information was obtained without removing any of the wrappings or causing any damage thanks to CT scans. Scientists have determined the age and sex of the mummies, cause of death, what they looked like (one had curly hair), and what objects were wrapped with them.
These mummies are currently on display at The Field Museum in Chicago, IL. Along with the mummies are images of their CT scans and viewers can "scan" a mummy in an interactive exhibit. If you live in the Chicago area go check out this exhibit and be proud that the technology that drives your career is also fueling ancient discoveries.
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While colorectal cancer is the second leading cause of death from cancer in the United States and third most frequently diagnosed cancer, many people are reluctant to have a colonoscopy. Colonoscopies are procedures that look for pre-cancerous growths or polyps, cancer, or other diseases of the large intestine. While cost and lack of access to healthcare are among the reasons people cite for not having the screening, it is also an invasive and uncomfortable exam. In a standard colonoscopy, which is normally used with people age 50 and older, a doctor slides a long flexible tube with a camera into the patient's rectum to view the colon. Patients have to take laxatives to empty the colon and undergo sedation before the procedure. They also have to go home afterwards and rest for the remainder of the day.
Virtual colonoscopy with the use of CT technology is an alternative for patients 65 and older, according to the American College of Radiology Imaging Network. The patient still has to undergo colon cleansing but requires no sedation and no tube or cameras are inserted into the colon. There is just a minimal insertion of a small enema tip into the rectum that blows carbon dioxide into the colon to inflate it, and then the patient passes through the CT machine that takes a series of x-ray images of the large intestine. This test requires no down time and the 3-D images that can be reconstructed offer doctors an excellent view of the colon.
It is important to know that different diagnostic and treatment options exist, especially for procedures that patients may shy away from that could ultimately be life saving. The human body is a complex machine and it only functions when all systems are properly cared for and maintained.
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Men and women returning from war need help and sometimes that help comes with four legs and fur. Veterans are being paired with companion dogs to help them navigate the delicate re-entry back into civilian life. They also help them cope with the symptoms of post traumatic stress disorder, depression, and anxiety.
One such service dog named Sadie in Charlotte, NC has been suffering from a tennis ball-size lump over her left eye. She is in need of a CT scan and most likely surgery. However, her owner does not have the funds to cover the procedures. The cost is estimated at $4000 by a veterinary ophthalmologist. When the word got out around town people lined up at Wells Fargo Bank branches to donate money. Other folks called the veteran directly offering to pay for all of the medical bills. The story was also posted on Facebook and people from Los Angeles to Boston made donations.
This outpouring of generosity inspired Sadie's owner to set up a non-profit foundation to help other veterans care for their service dogs. This was made possible with the overwhelming number of donations. One veterinarian even offered to take complete care of Sadie "pro bone o."
Helping others, whether canine or human, is contagious. It makes people feel good to reach out and lend a hand.
Sadie has now been properly care for and is back in good health, ready to help her best friend take on the world.
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February is American Heart Month and we all need to sit up and take notice, especially women. Heart disease is the leading cause of death among women in the United States, according to the Centers for Disease Control. Smokers, diabetics, and the obese are at higher risk.
If you are having heart related symptoms and visit your doctor, any number of tests could be ordered. The five most common ones are an EKG, carotid ultrasound, echocardiogram, stress test, or a cardiac CT scan. However, if you are asymptomatic no tests are necessary. "If you do a test like a stress test on someone who doesn't have any symptoms, then you are more likely to get a false-positive test than a true positive," said Dr. Malissa Wood, a spokesperson for the American Heart Association.
No test can prevent heart disease. Make sure you get daily exercise, eat plenty of fruits and veggies and don't smoke. Know your blood pressure and cholesterol readings and keep them under control.
If you suffer a broken heart there's no need to consult a Cardiologist. It will heal with time, caring friends, and the courage to love again.