CT Scans.

[Keithl]

I’ve had this same question. I had surgery in April 2015 at age 41 (almost 42) and have an aortic mechanical valve conduit. My surgeon wants ct scans every 2 years. However, I am guessing his average patent is much older. I went for the first “2 year post-op” ct scan in 2017, but didn’t go last year. I am very concerned about the radiation, as I had two pre-op (heart and brain) ct scans and one ct scan 6 weeks post op, so I have now had four (and it will cost me almost 6,000 or 7,000 for the ct scan, until I hit my crazy deductible). I see my cardiologist every year and occasionally have echos. I have had a few echos, but I think my cardiologist generally does them every ten years. My surgeon agreed I could go for a ct scan every three years so I will have less radiation exposure (so next year) but I’m not sure I want to go. Each scan is with contrast. Not sure if it matters but I’m only 4 ft 10 and 100 lbs and I doubt they adjust for my kid-like size when dosing. I’m sorry I am no help, but I am interested in the responses you receive.

I would go for MRIs. Some surgeons and cardios prefer CTs as that is what they are used to for years. My cardio wants regular echos then I frequent scans, but I have not talked about MRIs yet as I have 8 more months before next scan.

 

[Astro]

I could not find any hard number but my cardiologist told me half-life of CT radiation is very long. Meaning the radiation stays within the body for a long time.

If the purpose of CT scan is to track the progression of aneurysm, I would do MRA. The difference of insurance cost is only $300-$400. I would also consider repair the aorta sooner than later to avoid additional scans.

CT radiation does not stay in your body. It is electromagnetic radiation that flies through or is absorbed by the body. When it is absorbed, it transfers energy which can disrupt molecules (like DNA) in the body. It flies through or is absorbed in a near instant. It is safe for your family to hug you after a CT scan because the radiation is gone. However, the DNA damage is lasting and can potentially create trouble years later. Maybe your doctor was referring to the DNA damage.

 

[Keithl]

Interesting 10 years huh ... I have the same with Photographic Fixer (Black and White chemistry) ... right now its just at the rash from contact stage ...

Happily I'm as yet allergic to not much else (well except bullsh1t, which makes my job difficult for me, I'm surrounded by it), I've been very fortunate in my life.

Well that is about how long since last CT. I went MRIs since then until this year when cardio wanted CT again. 3 CTs this year, first scan in January was when I had the reaction, the other 2 were fine now that I take the prep. 3 doses of 50mg Prednisone at 13, 7 and 1 hour before scan then 2x25mg Benadryl 1 hour before. Made it through with no reactions or symptoms at all. This is the only thing I have been allergic to in my entire life.

 

[Keithl]

I have had 12 ct scans in the last 9 years. My cardiologist was alternating echoes and ct yearly. But I had lung cancer (stage 1) 2 years ago that was actually caught by the cardiologist’s ct scan. Upper lobe of right lung was removed but no treatment was necessary. Now I have annual echoes with my cardiologist and annual ct’s with my oncologist. So I guess you have to weigh the good and bad. They never would have found my lung cancer until it was probably too late without the ct scan.

Yeah I plan on resisting any more CTs as the scan showed 4mm nodules that the surgeon says can turn into lung cancer, no reason to help push that along with more radiation.

 

[pellicle]

CT radiation does not stay in your body...

in a nutshell X-Rays (as Astro says in other words) are ionizing radiation. Think that its got so much more energy as a particle that it moves from nerf gun to bullet. All light and radio is radiation, but when energy goes up out of the visible spectra it moves towards a radiation which is harmful (like UV and above, from Wikipedia (I bolded and italicized the important point):

Non-ionizing (or non-ionising) radiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum (photon energy) to ionize atoms or molecules—that is, to completely remove an electron from an atom or molecule.​

 

[themalteser]

@all - Thank you so much for all the excellent information you have provided me. From what I understand is that CT scans can increases the chance of cancers, but the chance may be quite small. MRI is a much better option, but due to PEARS procedure, unfortunately (and I do not know what the reasons are exactly), they cannot use MRI images to produce the PEARS sleeve. Perhaps because CTs are more clearer?

In addition to this, there is also an issue with the dye to worry about. Is the dye always needed to perform a heart CT? Is it because it produces better images?

Again, very helpful posts. May ask my surgeon why cannot I have MRI instead of CT.

 

[Protimenow]

The CT and MRI use very different processes. The MRI gathers a LOT of data from many sensors all around the ring that is used to gather data (as I understand it) and a computer creates an image from the data. I don't think it can accurately create images that can be accurately measured. It gives a good look into what's going on, but not an image that can be counted on for accurate measurement.

A CT, by contrast (no pun intended), WITH contrast, is a series of actual X-Ray images. There are actual X-Ray beams projected through the tissue, and from these multiple X-Rays, measurable images can be formed.

As Astro noted, CT radiation passes through the body - it doesn't linger IN the body, but its damage to tissues CAN persist. Too many X-Rays, and the possibility of negative reactions (like cancers) increases.

For the purposes of measuring so that an accurate PEARS sleeve is concerned, an MRI is of little value.

 

[tom in MO]

If you want to judge relative risk, think of this...If your aneurysm bursts you are dead.

CT and MRI machines use different processes. From US NIH:

• MRIs employ powerful magnets which produce a strong magnetic field that forces protons in the body to align with that field. When a radiofrequency current is then pulsed through the patient, the protons are stimulated, and spin out of equilibrium, straining against the pull of the magnetic field. When the radiofrequency field is turned off, the MRI sensors are able to detect the energy released as the protons realign with the magnetic field. The time it takes for the protons to realign with the magnetic field, as well as the amount of energy released, changes depending on the environment and the chemical nature of the molecules. Physicians are able to tell the difference between various types of tissues based on these magnetic properties. An MRI can measure chemical changes over time.
• Are there risks to MRI? Although MRI does not emit the ionizing radiation that is found in x-ray and CT imaging, it does employ a strong magnetic field. The magnetic field extends beyond the machine and exerts very powerful forces on objects of iron, some steels, and other magnetizable objects; it is strong enough to fling a wheelchair across the room. Patients should notify their physicians of any form of medical or implant prior to an MR scan. When having an MRI scan, the following should be taken into consideration:
  • People with implants, particularly those containing iron, — pacemakers, vagus nerve stimulators, implantable cardioverter- defibrillators, loop recorders, insulin pumps, cochlear implants, deep brain stimulators, and capsules from capsule endoscopy should not enter an MRI machine.
  • Noise—loud noise commonly referred to as clicking and beeping, as well as sound intensity up to 120 decibels in certain MR scanners, may require special ear protection.
  • Nerve Stimulation—a twitching sensation sometimes results from the rapidly switched fields in the MRI.
  • Contrast agents—patients with severe renal failure who require dialysis may risk a rare but serious illness called nephrogenic systemic fibrosis that may be linked to the use of certain gadolinium-containing agents, such as gadodiamide and others. Although a causal link has not been established, current guidelines in the United States recommend that dialysis patients should only receive gadolinium agents when essential, and that dialysis should be performed as soon as possible after the scan to remove the agent from the body promptly.
  • Pregnancy—while no effects have been demonstrated on the fetus, it is recommended that MRI scans be avoided as a precaution especially in the first trimester of pregnancy when the fetus’ organs are being formed and contrast agents, if used, could enter the fetal bloodstream.
    New open MRI machine
  • Claustrophobia.
• Are there risks for CT Scans? CT scans can diagnose possibly life-threatening conditions such as hemorrhage, blood clots, or cancer. An early diagnosis of these conditions could potentially be life-saving. However, CT scans use x-rays, and all x-rays produce ionizing radiation. Ionizing radiation has the potential to cause biological effects in living tissue. This is a risk that increases with the number of exposures added up over the life of an individual. However, the risk of developing cancer from radiation exposure is generally small. A CT scan in a pregnant woman poses no known risks to the baby if the area of the body being imaged isn’t the abdomen or pelvis. In general, if imaging of the abdomen and pelvis is needed, doctors prefer to use exams that do not use radiation, such as MRI or ultrasound. However, if neither of those can provide the answers needed, or there is an emergency or other time constraint, CT may be an acceptable alternative imaging option. In some patients, contrast agents may cause allergic reactions, or in rare cases, temporary kidney failure. IV contrast agents should not be administered to patients with abnormal kidney function since they may induce a further reduction of kidney function, which may sometimes become permanent. Children are more sensitive to ionizing radiation and have a longer life expectancy and, thus, a higher relative risk for developing cancer than adults. Parents may want to ask the technologist or doctor if their machine settings have been adjusted for children.

From: https://www.radiologyinfo.org/en/info.cfm?pg=safety-xray A CT to the chest is about 2 years worth of normal radiation. A CT of the abdomen and pelvis is about 3 years.

Per a friend, being in Sweden during and after Chernobyl, he got more than a life-times worth of radiation. This was measured by safety personnel at Argonne National Labs.

 

[Protimenow]

If you want to judge relative risk, think of this...If your aneurysm bursts you are dead.

CT and MRI machines use different processes. From US NIH:

• MRIs employ powerful magnets which produce a strong magnetic field that forces protons in the body to align with that field. When a radiofrequency current is then pulsed through the patient, the protons are stimulated, and spin out of equilibrium, straining against the pull of the magnetic field. When the radiofrequency field is turned off, the MRI sensors are able to detect the energy released as the protons realign with the magnetic field. The time it takes for the protons to realign with the magnetic field, as well as the amount of energy released, changes depending on the environment and the chemical nature of the molecules. Physicians are able to tell the difference between various types of tissues based on these magnetic properties. An MRI can measure chemical changes over time.
• Are there risks to MRI? Although MRI does not emit the ionizing radiation that is found in x-ray and CT imaging, it does employ a strong magnetic field. The magnetic field extends beyond the machine and exerts very powerful forces on objects of iron, some steels, and other magnetizable objects; it is strong enough to fling a wheelchair across the room. Patients should notify their physicians of any form of medical or implant prior to an MR scan. When having an MRI scan, the following should be taken into consideration:
  • People with implants, particularly those containing iron, — pacemakers, vagus nerve stimulators, implantable cardioverter- defibrillators, loop recorders, insulin pumps, cochlear implants, deep brain stimulators, and capsules from capsule endoscopy should not enter an MRI machine.
  • Noise—loud noise commonly referred to as clicking and beeping, as well as sound intensity up to 120 decibels in certain MR scanners, may require special ear protection.
  • Nerve Stimulation—a twitching sensation sometimes results from the rapidly switched fields in the MRI.
  • Contrast agents—patients with severe renal failure who require dialysis may risk a rare but serious illness called nephrogenic systemic fibrosis that may be linked to the use of certain gadolinium-containing agents, such as gadodiamide and others. Although a causal link has not been established, current guidelines in the United States recommend that dialysis patients should only receive gadolinium agents when essential, and that dialysis should be performed as soon as possible after the scan to remove the agent from the body promptly.
  • Pregnancy—while no effects have been demonstrated on the fetus, it is recommended that MRI scans be avoided as a precaution especially in the first trimester of pregnancy when the fetus’ organs are being formed and contrast agents, if used, could enter the fetal bloodstream.
    New open MRI machine
  • Claustrophobia.
• Are there risks for CT Scans? CT scans can diagnose possibly life-threatening conditions such as hemorrhage, blood clots, or cancer. An early diagnosis of these conditions could potentially be life-saving. However, CT scans use x-rays, and all x-rays produce ionizing radiation. Ionizing radiation has the potential to cause biological effects in living tissue. This is a risk that increases with the number of exposures added up over the life of an individual. However, the risk of developing cancer from radiation exposure is generally small. A CT scan in a pregnant woman poses no known risks to the baby if the area of the body being imaged isn’t the abdomen or pelvis. In general, if imaging of the abdomen and pelvis is needed, doctors prefer to use exams that do not use radiation, such as MRI or ultrasound. However, if neither of those can provide the answers needed, or there is an emergency or other time constraint, CT may be an acceptable alternative imaging option. In some patients, contrast agents may cause allergic reactions, or in rare cases, temporary kidney failure. IV contrast agents should not be administered to patients with abnormal kidney function since they may induce a further reduction of kidney function, which may sometimes become permanent. Children are more sensitive to ionizing radiation and have a longer life expectancy and, thus, a higher relative risk for developing cancer than adults. Parents may want to ask the technologist or doctor if their machine settings have been adjusted for children.

From: https://www.radiologyinfo.org/en/info.cfm?pg=safety-xray A CT to the chest is about 2 years worth of normal radiation. A CT of the abdomen and pelvis is about 3 years.

Per a friend, being in Sweden during and after Chernobyl, he got more than a life-times worth of radiation. This was measured by safety personnel at Argonne National Labs.

They're probably getting more than a lifetime of radiation in portions of the Ukraine, where a 'missile test' failed a few weeks ago.

 

[Keithl]

The CT and MRI use very different processes. The MRI gathers a LOT of data from many sensors all around the ring that is used to gather data (as I understand it) and a computer creates an image from the data. I don't think it can accurately create images that can be accurately measured. It gives a good look into what's going on, but not an image that can be counted on for accurate measurement.

A CT, by contrast (no pun intended), WITH contrast, is a series of actual X-Ray images. There are actual X-Ray beams projected through the tissue, and from these multiple X-Rays, measurable images can be formed.

As Astro noted, CT radiation passes through the body - it doesn't linger IN the body, but its damage to tissues CAN persist. Too many X-Rays, and the possibility of negative reactions (like cancers) increases.

For the purposes of measuring so that an accurate PEARS sleeve is concerned, an MRI is of little value.

So while my various cardiologists have said a CT is the gold standard they have also said an MRI is darn close except in really extreme cases. My guess as I have done went for MRIs all the time until the measurement got close then they wanted a CT. I have all my MRI and honestly they seem to show some darn good details.

 

[PAN]

Always liked this image..

P

 

[pellicle]

Always liked this image..

What's missing is health risk significance of those doses

https://en.m.wikipedia.org/wiki/Ramsar,_Mazandaran

Ramsar's Talesh Mahalleh district is the most radioactive inhabited area known on Earth, due to nearby hot springs and building materials originating from them.[6] A combined population of 2,000 residents from this district and other high radiation neighbourhoods receive an average radiation dose of 10 mGy per year, ten times more than the ICRP recommended limit for exposure to the public from artificial sources.[7] Record levels were found in a house where the effective radiation dose due to external radiation was 131 mSv/a, and the committed dose from radon was 72 mSv/a.[8] This unique case is over 80 times higher than the world average background radiation.​

​

The prevailing model of radiation-induced cancer posits that the risk rises linearly with dose at a rate of 5% per Sv. If this linear no-threshold model is correct, it should be possible to observe an increased incidence of cancer in Ramsar through careful long-term studies currently[when?] underway.[7] Early anecdotal evidence from local doctors and preliminary cytogenetic studies suggested that there may be no such harmful effect, and possibly even a radioadaptive effect.[9] More recent epidemiological data show a slightly reduced lung cancer rate[10] and non-significantly elevated morbidity, but the small size of the population (only 1800 inhabitants in the high-background areas) will require a longer monitoring period to draw definitive conclusions.[11] Furthermore, there are questions regarding possible non-cancer effects of the radiation background. An Iranian study has shown that people in the area have a significantly higher expression of CD69 gene and also a higher incidence of stable and unstable chromosomal aberrations.[12]Chromosomal aberrations have been found in other studies[13] and a possible elevation of female infertility has been reported.[14]​

 

[PAN]

Very true. It's an interesting topic. I have heard of Ramsar and other such places. Many with below average incidences of cancers. There is a plot that I cannot find right now that suggests a low "healthy" dose may actually prevent cancer. I'm pretty sure 7mSv for a chest CT exceeds that though.

For the most part, they are a necessity. It's a requirement to accurately treat a current problem, as we all know. Any health risk guideline may be quite a broad one. I admit it would be interesting to read but would it be helpful if I needed a scan? I'd just need to be sure I needed the scan.

Is one doctor prone to over imaging when compared to another. That is no doubt probably true. If I was being subjected to repeat scans there would need to be a very good reason for it.

p

 

[JWalters]

I enjoyed this explanation about radiation exposure :

 

[pellicle]

I enjoyed this explanation about radiation exposure :

sleeping next to someone ... lots of reasons that could be dangerous ... especially if you snore and your wife is a light sleeper.

;-)