CT Scans

Barcode

Yes, you told me so The radiologist said only the really ancient MRI machines are closed in (obviously, the person who designed it never had to go inside one).

I'm expecting some sort of abnormality on the MRI. After all, people don't have nerve-deafness due to nothing. But I've had it for so long, that I can't imagine it will be anything serious. It's more curiosity of finding out where my inner ear structure differs from a normal persons. If there are paragangliomas, I can deal with that too. People hear the word "tumor" and panic; but in some cases, you can live with benign things for aeons without any bad symptoms.

Savvy_Sue

Barcode wrote: »

People hear the word "tumor" and panic; but in some cases, you can live with benign things for aeons without any bad symptoms.

Seconded ...

beechescomposter

Hallo again Barcode
I may have missed it but if you had MRI for nerve deafness they are looking for acoustic neuroma - a benign tumour of the auditory nerve. Can be bilateral in a condition called Von Recklinghausens Syndrome or Neurofibromatosis. These only show up on MRI unless huge.
It is dangerous to assume that everything is ok if you don't hear anything. There is no fail safe mechanism in most hospitals. If the result does not get back to your doctor he will not be reminded to chase up the result. If you don't hear (sorry) anything in a couple of weeks chase it up yourself or at least ask if the scan has been reported.
If it is Neurofibromatosis and they are planning annual CT scans you should be aware of the significant cumulative risk from radiation. This will be important in a young person. I don't want to give out the figures because it would cause alarm but it might be possible to monitor your abdomen with MRI (if its the adrenals they are interested in). I may, however, be completely off track and writing b0110cks because I don't know why you are having the scans.

Need_More_Money_2

beechescomposter wrote: »

If it is Neurofibromatosis and they are planning annual CT scans you should be aware of the significant cumulative risk from radiation.

I have to pick up on this as I think it could be rather alarmist. Firstly it is important to realise that there may be NO risk from low level radiation. If there is a risk from the dose levels associated with CT it is small and I really would not be concerned about it at all if you're having scans for good medical reasons.

The risks associated with low level radiation are almost always grossly overstated. You should be aware that there is NO evidence of harm from the dose levels up to 25-30 times that from a typical CT scan.

Barcode

beechescomposter wrote: »

Hallo again Barcode
I may have missed it but if you had MRI for nerve deafness they are looking for acoustic neuroma - a benign tumour of the auditory nerve. Can be bilateral in a condition called Von Recklinghausens Syndrome or Neurofibromatosis. These only show up on MRI unless huge.

I don't have either of those conditions. The reason I'm having an MRI/CT is because I have a mutation in the SDHB gene which is known to cause pheochromocytomas and paragangliomas. There is a slight suspicion I may have an inner ear tumour - but it would be odd for the condition to be bilateral. It's most likely unrelated, and just one of those things.

If my scans are clear, then follow up is annual. I think it's a CT scan of the abdomen/pelvis annually, and a scan of the thorax/head every three years (tumours are rarer there). Presumably, any "risks" of radiation are far outweighed by the benefits of detecting a potentially life-threatening tumour and treating it before it turns into a huge problem.

beechescomposter

Need_More_Money wrote: »

I have to pick up on this as I think it could be rather alarmist. Firstly it is important to realise that there may be NO risk from low level radiation. If there is a risk from the dose levels associated with CT it is small and I really would not be concerned about it at all if you're having scans for good medical reasons.

The risks associated with low level radiation are almost always grossly overstated. You should be aware that there is NO evidence of harm from the dose levels up to 25-30 times that from a typical CT scan.

This is just wrong and you need to read the BEIR VII report if you work in the radiation field as I do. If you don't have special knowledge of the subject you should not be making such statements. Below is the conclusion of a recent article in Applied Radiology 2007; 36(6)

Conclusion

It is essential that the radiology community be committed to dose reduction. The community is responsibile for educating patients about the radiation risks and the use of alternative, safe imaging modalities––in particular, with emphasis on US and MRI––for the foreseeable future. Educational efforts should be directed to radiologists, referring physicians, regulators, public health officials, and patients. A key component for optimizing patient safety should be an aggressive assessment process to limit the improper use of CT.
The BEIR VII Report represents an updated consensus evaluation on low-dose ionizing radiation risks, in the range of exposures associated with routine clinical body CT examinations. These estimates show that the estimated risk is sufficiently significant that clinicians, as patient advocates, should include radiation risk as a component of obtaining informed consent from the patient prior to a CT study. As a routine component to the process of informed consent, clinicians should also discuss and be able to offer an alternative, such as an MRI study, when it can be argued that the MRI examination may provide similar or superior diagnostic results with lower short- and long-term health risks.
When CT examinations are performed, the current responsibility falls on the radiologist who is interpreting the study to ensure that the optimal CT protocol is implemented and that this includes utilizing a technique that will minimize radiation exposure while maintaining the diagnostic sensitivity and specificity of the examination. This includes restricting the dose rate and the field of view imaged. Specific strategies could be considered for particular indications. For example, in many cases, liver examinations using multiple-pass contrast-enhanced studies may be restricted to a single pass, and MRI can be used if the CT study is nondiagnostic. If a patient and clinician choose an MR examination, challenges in our current system include having adequate availability, having adequate expertise in the performance and interpretation of these studies, and obtaining approval for coverage of the MRI costs from the medical insurer. These are surmountable problems, however, and the solution will largely depend upon a greater concerted effort of clinicians to act as patient advocates.

Barcode, thank you for the information about the SDHB gene. I have learnt my new thing for today. The risks of CT have to be balanced by the benefits of making a diagnosis as you correctly say. I am just pointing out that MRI can do this (in the abdomen/pelvis) with no known risk.

Need_More_Money_2

Barcode wrote: »

If my scans are clear, then follow up is annual. I think it's a CT scan of the abdomen/pelvis annually, and a scan of the thorax/head every three years (tumours are rarer there). Presumably, any "risks" of radiation are far outweighed by the benefits of detecting a potentially life-threatening tumour and treating it before it turns into a huge problem.

Exactly. There is an assumed theoretical risk which is almost certaintly much higher than the actual risk (if indeed there is a risk at all). By law, every medical procedure involving ionising radiation has to be individually clinically justified to show that the benefits outweigh these theoretical risks.

Need_More_Money_2

beechescomposter wrote: »

This is just wrong and you need to read the BEIR VII report if you work in the radiation field as I do. If you don't have special knowledge of the subject you should not be making such statements.

I do

beechescomposter wrote: »

Below is the conclusion of a recent article in Applied Radiology 2007; 36(6)

You have to remember that this is based on the linear no threshold HYPOTHESIS, which is incredibly bad science. There is no evidence of harm below about 100-200mSv. There is some (weak) evidence of beneficial effects of radiation at low doses though!
The exposure to radiation from medical sources is already very tightly regulated (over regulated in my opinion) by the Ionising Radiation (Medical Exposures) Regulations. These mean that the exposures have to be based on a net benefit to the patient, even based on the overstimates of risk.

If people are frightened into not having clinically necessary procedures, their health will almost certainly suffer.

Barcode

Thanks Beeches. In the booklet York hospital sent me, it says (to paraphrase) that the radiation exposure from a CT scan is about the same as that you would normally be exposed to in around three years by natural means.

I'm not sure if the MRI can do the same thing (?). This might be because some tumours tend to show up on certain scans and not others. My brother's pheo, for instance, was detected by a CT scan after he had some contrast dye. I don't know if it would have shown as clearly on an MRI.

I hadn't heard of words like pheochromocytoma and SDHB until last year. Now I'm a bit more informed. The only thing that surprises me is why more things DON'T go wrong in our bodies given the damage our DNA receives on a daily basis. As I understand it, having a mutation doesn't guarantee you will develop a tumour; but the soldier is not guarding the door, so to speak. And for that reason, it's sensible to have annual screening.

Need_More_Money_2

Barcode wrote: »

Thanks Beeches. In the booklet York hospital sent me, it says (to paraphrase) that the radiation exposure from a CT scan is about the same as that you would normally be exposed to in around three years by natural means.

That sounds about right. Dose from CT depends on exact procedure and body part but is around 6-8mSv if I recall correctly. Average natural background is around 2.6mSv in the UK but varies. It is particulary higher in Aberdeen and Cornwall, so if you lived there for a few years you would get the same extra dose as from a CT scan anyway. Data from the USA shows that states with higher natural background radiation actually have lower incidences of cancer than those with low natural background levels. There are many other variables so this is hard to interpret, but it certainly does not support the theory that low level radiation is harmful.

Barcode wrote: »

I'm not sure if the MRI can do the same thing (?). This might be because some tumours tend to show up on certain scans and not others. My brother's pheo, for instance, was detected by a CT scan after he had some contrast dye. I don't know if it would have shown as clearly on an MRI.

Someone (probably a radiologist) has a legal responsibility to ensure that the procedure performed is the appropriate one. If it can be done as sucessfully with MRI then that is what will be done.