ANA Discussion Forum
General Category => Inquiries => Topic started by: shygirl on July 20, 2008, 07:58:29 pm
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Hi all-
I was looking at the mri CD and found a different view. Well, I measured it on the "new" view and it measured 2.1 cm. The Drs told me it was 1.8 cm. Now I find this new measurement and I'm kinda freaked by it.
Has anyone else had a Dr mismeasure the size?
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Yes, but usually only by 1 mm. My doctors at Stanford came up with the same measurements as me, but the lab where both my MRIs were done cited some measurements that were 1 mm smaller or larger in both MRIs.
Be sure that you're only measuring that portion which is truly white. At the lateral extent of the IAC, the IAC may appear gray and you might mistake that to be part of the tumor. That can mistakenly add 1 or 2 mm to your measurement.
Best wishes,
Tumbleweed
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Tumbleweed-
It was just the bright white "blob". I first looked at it from the side view and it measured 1.8. When I found the view from the top of my head, that's when it got bigger. I assume the Drs didn't measure the "tail" which was extending from the IAC. It looks that way, at least.
Thanks for your reply.
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My initial MRI report stated that the "largest" dimension was 2.4 cm. The one 6 months afterwards, was more like 2.9 cm. Of course I totally freaked out, because I thought this was some kind of wacky growth. Then I went back and checked the original MRI scans on the CD myself. The 2.4 cm referred to the coronal (vertical dimension), whereas the axial dimension was more like 2.7 cm, according to my measurements. And the number of slices was much less, which means that it could have been even larger. To make things worse, some of the doctors I consulted afterwards counted the portion in the IAC in, and this gave a measurement of 3.5 cm :o. I have no idea to this day how the radiologist came up with the 2.4 cm measurement, but I am still upset about it.
Marianna
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Marianna, I've seen a few inconsistencies in my MRI reports, even though I've only had two! The first one said the medial extent of my then 1.8cm (I measured 1.9) tumor was 2 mm from the fundus of my IAC -- which is anatomically impossible. When I pointed out they must've meant to write lateral extent, they said they'd fix that sentence in the followup report.
Best,
Tumbleweed
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FWIW: I just let my neurosurgeon do the measuring. He is very well aware of all the variables involved in MRI scans and can analyze the AN and determine it's actual size much better than I ever could. Besides, that what he gets paid to do. But that's just me. :)
Jim
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I do understand that the measurements can be off a bit here and there. If the typical growth is 1-2mm a year, then how can the doctors be sure the AN has grown if the measurements can possibly be off by one mm. I have had four MRIs with contrast at the same place done by the same person. Three have shown no growth. However, the second one showed a measurement that was 2mm different from the first one. My doctor didn't think the AN had grown so he had another doc measure it, and that doc sided with my doc about no growth. This last MRI showed a slight amount of growth that I guess you could say is so small that it could be a measurement question. However, if you put all of the MRIs side by side you can definitely see by eye that the AN has a different shape. Can an AN stay basically the same size for the most part, but at the same time change its shape? In my case it went from about a 3/4 moon shape to a round moon. It is so obvious. I tend to think it really has grown and 8 doctors think so, too.
Nancy
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Thanks everyone. I really appreciate the input.
I knew the measurement could be off, but I didn't expect 3 mm. I talked to my ENT today and he said they just measured the largest part. Not the length. Okay. He said it was probably longer than 2.1 cm due to the part inside the IAC that was unseen. I guess the fact that it went from a small size to medium just got me wondering. It's gone, so I won't worry about it now. :)
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FWIW: I just let my neurosurgeon do the measuring. He is very well aware of all the variables involved in MRI scans and can analyze the AN and determine it's actual size much better than I ever could. Besides, that what he gets paid to do. But that's just me. :)
I'm with you Jim. I leave measurements up to my neurotologist and the radiologist who reads the MRI.
My degree is in business; not medicine, so I figure they understand this stuff much better than I do.
Jan
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At Stanford, they measured my AN in tenths of a mm. I trust their measurements more than those that the imaging center did.
Tumbleweed
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Just a side note off the subject. Some of you have done so much research that you should be given an honorary medical degree. This stuff is just way over my head.
Nancy
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Just a side note off the subject. Some of you have done so much research that you should be given an honorary medical degree. This stuff is just way over my head.
So, true, Nancy. I especially love to read posts by Mark. Where he learned everything he learned, I'll never know, but it truly fascinates me 8)
Jan
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The neurosurgeon never told me the measurements, the neurotologist did(and I had to ask him). No radiology report--I was simply curious is all.
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Nancy Drew's quote about honorary degree so funny, I do feel like I am taking a course. It makes me wonder about a couple things......seeing size matters here, does the shape? and I wonder if different places where you have MRI's can vary with their technique so there can be variations?
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Rivergirl, the shape does matter in so far as it determines the volume of the tumor -- which is really more important than the dimension along any one of the three axes of measurement. A spherical tumor has much greater volume than an elliptical one, for example. The larger the tumor volume is, the more important structures it presses against and the more difficult it is to treat without causing collateral damage. At least this is my understanding. Dr. Chang recently told me that most people place too much emphasis on the single greatest axial measurement and said in so many words that the tumor volume is generally more important.
There can be variations in MRI results depending on where it's taken, but I'm not sure if technique is one of the variables (I would think the specific equipment used would be a factor). All I know is that Stanford (where I was treated) and specifically Dr. Chang told me that they would prefer to perform my followup MRIs instead of me having it done elsewhere. I got the feeling that they felt doing so would either yield more consistent or more accurate results. They were open to me having the MRI performed elsewhere, but had a clear preference to do it in-house.
Best,
Tumbleweed
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Thanks Tumbleweed, there isn't a day I don't learn something new about these darn things.
I have another question: Why are so many here choosing CK? my understanding is it is not 100% and may damage more of the hearing and if you have regrowth it is alot harder to re-treat.
And what is the benefit of having a CAT scan? My Dr. is also looking at ruling out a condition called something, something dehiscence, as anyone else been worked up for this?
I am glad so many of you have honorary medical degrees.
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Hi Rivergirl,
Surgery and radiation both fail occasionally, and both fail at about the same rate, around 1-2%. Fairly recently, for instance, Carrie (CMP) had a regrowth after surgery, and Kathleen had a regrowth after radiation. Stanford has had about 1 failure in every 100 cases treated with CK.
Radiation is gentler to nerves than surgery. For hearing preservation, it is somewhat better, depending on which surgery you compare it to; for facial nerve, it is distinctly better, with very few cases of facial nerve issues after treatment. It has the best chance at preserving hearing for smaller tumors, as well as avoiding facial nerve issues.
The "what if it regrows and is harder to treat" argument has been discussed numerous times on the forum. First of all, the chance of it happening is small. Second, "harder to treat" doesn't mean much, unless it means facial nerve damage or some other side effect. Kathleen just sailed through surgery, apparently with facial nerve function in great shape. One study put it at about a 25% chance of damage. Multiply that by a 2% chance of regrowth in the first place, and you are talking about a 0.5% chance of a facial nerve issue - not enough to worry about.
Which is why I think so many here are choosing CK. :)
Steve
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I agree with Steve, but will add that, IMO, the chance of hearing preservation is greatest with treating large tumors with radiosurgery, too. That's because a large tumor virtually always requires either a translabyrinthine or retrosigmoid surgical approach. Translab destroys all hearing structures on the affected side, leaving the patient deaf. Retrosigmoid surgery for a large tumor almost always results in complete loss of hearing (although there are exceptions).
Here is an excerpt of a post I wrote a few months ago, before receiving CK. It goes into more detail comparing surgery with radiosurgery (both GK and CK):
With surgerical resection (cutting the tumor out), you run a much higher risk of damage to facial nerve function compared with radiosurgery's results in that regard. For example, with my size tumor, I stand about a 31% chance of permanent ipsilateral facial paralysis with surgery, but only 1% chance of same with GammaKnife or CyberKnife treatment. Resection also poses other risks: roughly 10-15% chance of chronic headaches (thought to be due to bone dust being left behind inside the cranium after the operation), a slight chance of cerebrospinal fluid (CSF) leakage, and (very rarely) cognitive or behavioral changes (memory loss and personality changes). And in many cases, surgery involves cutting the vestibular (balance) nerve, whereas radiation treatment preserves the anatomical continuity (but not always full function) of the vestibular nerve. So I personally think you're on the right track with choosing some type of radiosurgery (one-time radiation treatment) or radiotherapy (fractionated radiation treatment, or that which is split up into multiple smaller doses). That said, radiosurgery/radiotherapy only (hopefully) kills the tumor and does not remove it (like resection would). The recurrence rate for surgery and radiation are about the same (cited to be roughly 2 to 3% in most studies).
As for radiosurgery, GammaKnife (GK) and CyberKnife (CK) are both more accurate than standard FSR (fractionated stereotactic radiation) such as Novalis. CK is also a form of fractionated radiotherapy, but its accuracy gives it a leg up on standard FSR.
CK delivers a more homogeneous dose to the tumor compared with GK. CK delivers only 15% higher dose to the center of the tumor than at the periphery, whereas GK delivers fully double (100% greater) dose at the center compared to at the periphery. CK advocates believe that GK's higher dose at the center of the tumor increases the chance of damage to nearby healthy tissue August 8,2008 P.S.: and especially to the vestibular nerve, which runs down the center of the internal auditory canal and therefore receives a full hit of radiation if the tumor fills the entire IAC. Also, GK delivers one large dose to the tumor because one treatment is all you can do with GK (this is because a ring is fitted to your head for the treatment and, once it's removed, there's no way to get it exactly in the same place for a second treatment). With CK, on the other hand, a thermoplastic mask is custom-fitted to your head and the tumor's location (in relation to the mask and your bony structures) is plotted into the computer; on followup visits for treatment, they put the mask on your head again and you're ready for the next dose. This flexibility allows CK to apply smaller doses to the tumor than GK with each treatment; together, the smaller doses add up to the same total biologically equivalent dose as you would get with GK's one and only treatment, but (theoretically, at least) the hearing nerve and other healthy tissue has time to recover in between treatments (whereas the tumor supposedly doesn't recover as quickly). Presumably due to the fractionating of dosage, studies show CK yields slightly better results at preserving hearing compared with results for GK. Furthermore, GK's ring is screwed into the head (the screws stop at the skull) to keep it stationary (so that the radiation stays focused on the tumor), a mildly invasive procedure. CK is totally non-invasive: a series of overhead X-rays tracks the patient's head movements and tells the computer-controlled CyberKnife machine which way to move to track any small movements the patient may make so that the radiation stays centered on the tumor. GK advocates say that's all well and good, but GK has about 40 years of track record, whereas CK has been around a lot less time and is not as proven of a treatment as GK. (CK was approved by the FDA in 1999, although Stanford University Medical Center has been using it since 1994 in clinical trials because their Dr. Adler invented CK.)
Best,
Tumbleweed
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Thanks Tumbleweed, there isn't a day I don't learn something new about these darn things.
I have another question: Why are so many here choosing CK? my understanding is it is not 100% and may damage more of the hearing and if you have regrowth it is alot harder to re-treat.
And what is the benefit of having a CAT scan? My Dr. is also looking at ruling out a condition called something, something dehiscence, as anyone else been worked up for this?
I am glad so many of you have honorary medical degrees.
It was suspected I had a temporal dehiscence when I complained to my doctor of oscillopsia, but this was ruled out as the MRI showed inflammation and hemorrhage in the inner ear. After 2nd surgery transcanal labyrinthectomy my surgeon noted "significant facial nerve prolapse/dehiscence."
What do your doctors feel is dehiscent?
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Tumbleweed, that was a great narrative, thanks.
Arushi, I do believe it was sub cranial dehiscence because when I cough or sneeze I want to lay on the floor where it is safe. I think it could be the tumor is a tube shape and fills the canal, perhaps it has itself pretty close to alot of the vestibular nerve. I ok with ruling it out though, he tells me it is fairly new diagnosis and rare (oh, I feel so special). What is oscillopsia? and was the hemorrhage caused by the AN?
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Tumbleweed, that was a great narrative, thanks.
What is oscillopsia?
Oscillopsia is a sensation that everything in your field of vision bounces up and down, most noticeable when you walk. Before I knew it had a medical name, I used to call it "shaky-camera syndrome," because everything bounced around like the view you get when you walk briskly or run with a camera and you're looking through the lens at the image. In my case, it was caused by severe damage to the vestibular nerve by the AN. It lasted 2 or 3 months, perhaps longer, and eventually went away as my balance systems compensated for my loss of vestibular function.
Dehiscence is the splitting open of a structure along definite structural lines (like a pea pod, for example, splits open when it ripens). If I remember correctly, dehiscence can be intracanicular, or pertaining to the internal auditory canal. I'm not sure what causes it, but obviously it can cause problems for the cranial nerves (facial, vestibular and hearing nerves) that run axially along the inside of the canal.
Best wishes,
Tumbleweed
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Rivergirl,
Never did find out what caused the hemhorrage, don't think the doc knows this either. My tumor had been removed three years prior, so not sure why these problems occured only to repeat what doc thinks might be autoimmune response? Who knows!
Tumbleweed,
Great explanations on oscillopsia and the dehiscence can also be present in the temporal bone too. I think some say it's caused by trauma to the head. Again, who knows for sure!