Hi, from one of your posts above, I just bought the $11 Flow meter from Amazon. Hope you get commission for it. 😀 Hank
Have you compared your scanner results to your catheterized voids yet? I would try your method and compare the result to the catherized voids or natural void differences. But in general, at least with m machine, the larger readings tend to be the most accurate. Question: Does the machine generated bladder outline match the shape of your bladder sonogram?
I've never been catheterized. When you say "bladder sonogram" I'm not sure what you are referring to.
I just discovered that the gain on the machine is set to 30 when it should be kept at the default of 20.
Have you then compared for example with first taking a scan on a full bladder, then voiding into a marked container, then scanning after the natural void? Then you compare the difference between the two scans to the amount in the container.
On my machine you see a real ultrasound image of the bladder. Then when I hit the "scan" buton, a broken line appears around what the machine thinks is the bladder and a number pops up which is the estimated bladder volume in ml. Does your machine do that?
On my machine, if the broken line doesn't conform to the bladder shape I have the ability to re-draw the line conforming to the bladder shape. Then I push another button and the machine re-calculates the bladder volume based on the re-drawn area.
I have an irregular bladder so half the time the machine gets my bladder shape the first time and half the time I have to re-draw it before computing the volume.
What setting are you talking about?
Jim
Oh...I see, the "gain" setting. I believe I've left it at the default setting.
Jim
I did test it using pre and post scans. The first time the difference was within 9.7% of the amount voided into a marked container. The second time it was within 3.5% of the amount voided into a marked container. I was just looking at training videos and the training videos also show multiple takes by an experienced operator that were 53 ml different. I also have NOT been looking at the image after the scan is over to see how well it fits the circled area on the screen with crossed lines at the center.
Yes it was the gain and I just set it back to the default.
Your test using re and post scans suggest your machine is very accurate. So whatever protocol you used seems to work. I will have to look at a video on how your scanner works to comment on the other point as Im not sure we are talking about the same thing.
If you look at the youtube video around the 2;14 mark, you will see the outline created around the blackend part of the image which is the bladder. You should check to make sure that line is being drawn accurately. On my machine you can actually adjust that line to better conform to the bladder if necessary. Your machine doesn't have that capability but it may not be necessary because of the 3d accuracy. If you want to see how my machine works in comparison, go to youtube and search for "Portascan Plus"
Jim
Hi Jim:
I'm assuming you are looking at the Laborie instructional video titled "Portascan 3D Proper Scanning Technique Instructional Video", which can be viewed on the Laborie website. At the 2:18 mark you will see the circle with crosshair lines. This is what I was referring to earlier as something I have not been paying attention to. I have been looking at the earlier image where the bladder is outlined with green lines and have been attempting to get the green outlined bladder to be centered in that image.
With regards to accuracy, it's not as simple as I led you to believe. For example, yesterday morning upon waking up I ran a series of pre and post void scans. Here are the results:
Time: 7:35 AM Prevoid Scan = 431 ml. Voided amount in measuring container = 200 ml. Post-void scan = 224 ml.
This looks really good in that 431 - 224 = 207 ml. This is within 3.5% of the 200 ml measured in the calibrated beaker.
However I voided again 12 minutes later and look at the results now:
Time: 7:47 AM Voided amount in measuring container = 190 ml. Post-void scan = 150 ml.
I did not take a prevoid scan at 7:47 AM because I figured that the post void scan from 7:35 would still be reasonably accurate. If approximately true, though, how could I have voided 190 ml with a PVR of 150 (the sum of which is 340ml), when the Post void scan from 7:35 AM resulted in only 224 ml of liquid left in the bladder? Is it possible that the kidneys produced 116 ml of urine in 12 minutes??!
So you see these results make me wonder. At any rate, I took a PVR scan this morning and paid particular attention to the comments I made in the first paragraph (circle with crosshairs). It took three tries, but I seem to have gotten the largest image nicely centered and taking up most of the circle (even though the amount was only 111 ml). My scan looks better than the one in the Laborie video at the 2:18 mark. Also notice in that video that the two readings shown are 59 ml different. I've seen this in some other videos using the Laborie device where a technician did real time back-to-back scans. I like this scanner, but you really have to search for the largest image and have to run multiple scans. It seems to be a feel issue.
Do you think it might be a good idea to get a phantom bladder? Do you know where I can get one cheap?
The bladder should not be "centered" in the green line, the green line should actually outline the bladder. Take a look at the videos of my machine and maybe you'll see it more clearly.
Your results seem very accurate to me. I'll take a better look later, but being off even 100ml is not a big deal. The idea is to get a general idea. Even the scanners in the doctor's offices are off sometimes more than you would imagine.
Depending on how active the kidneys are producing, it's quite possible that amount of urine was produced in 12 minutes or at least part of it. On the other hand it could just be a normal variance.
When I first cathed at my urologist's they gave me a 1000ml beaker to cath into based on a bladder scan 20 minutes earlier. I ended up voiding around 1500ml!!!! The PA was very perplexed because she was expecting less than 1000ml based on the scan. It was either scanner error or urine production within the 20 minutes, or a combo of both.
Jim
I don't think you need a phantom bladder based on your numbers and I may be wrong but the phantom bladders may be specific to a machine and are usually costly. Calibrating it against known volumes like you are doing should be as or more accurate.
I'm beginning to wonder if I'm scanning correctly. I'm laying in a supine position with my head a bit elevated and have the probe angled towards my anus (as best as I can). I get the largest readings when I push in a bit but I can also feel the probe resting against a hard thing, which I assume is the pubic bone. If I reposition the probe an inch or so closer to my head (away from the pubic bone), it is harder to get a stable image. The reading in this latter position, though, is 60 to 80 ml or so less. If the probe is resting against the pubic bone, then I'm wondering if it is also measuring the pubic bone and giving me a high reading. I saw a video where the nurse said that the bladder is beneath the pubic bone, which is why the probe needs to be angled (45 to 60 degrees). There are also scanners that warn you that the scan might be including the pubic bone. So now I'm confused.
With regards to the green lines, I really can't see the bladder easily in these real time images (with green lines). All of the scans in the video show the vertical green line pretty much splitting the green outline down the middle. They also say that the bladder silhouette should appear in the center of the cross hairs (I don't think they are talking about the image with the green lines, but after the image has been taken where there is a circle with crosshairs and a bladder silhouette in white). I think that the green lines are part of the pre-scan phase that helps you find the bladder.
Finally, with regards to accuracy, my research suggests that being off 100 ml is a big deal. A PVR of around 50 ml would be great at my age and with the BPH. However, I read that PVR values greater than 100 ml are a guideline at which potential action should be considered and that a PVR of 150 ml or higher indicates urinary retention. Do you agree with these guidelines? Thanks.
Let us know how it works out for you Hank. Sometimes I find it hard to tell where the urine level is especially if the urine color is a light color.
Looking for advice from anyone who will answer. I'm having considerable difficulty getting consistent bladder scan results. For example, I just took five scans after voiding and they were 85, 174, 173, 163, 130. Both the post-scan image of the 85 ml and 174 ml were in the center of the cross hairs and looked pretty circular. I took a pre-void scan and it resulted in a nice post-scan image that was dead center in the crosshairs of 240. The measured void amount was 150ml, so the 85 ml result would seem to make sense (assuming the 240 ml result was correct.
Should I always take the largest amount as the correct amount, esp. if the after scan image shows that it is well centered in the crosshairs?
Hi. As I menioned before you will find your answers by comparing scanned results with actual voided volumes. except for the 85 your results are very consistent. Also, it's not just the cross hairs, that's just for aiming, but you want to make sure that the outline drawn by the machine actually conforms to the actual bladder shape. If it doesn't then your reading will not be accurate.
Jim
It works well for such a simple device. You'd have to bend over to see the level, and it's not constant. So I try not to blink. Thanks. Hank
Hi Jim: To my understanding this particular scanner doesn't work that way. During the pre-scan there is a bladder image, which is very hard to see. To help discern it, it is surrounded by a green outline and there is also a green vertical line contained within this green outline (this is not the cross hair I've mentioned). You're supposed to subtly move the scanner around until this green vertical line is in the center of the green outline of the bladder (bisecting this green outline). Then you let go of the button and the scan finishes up. After the scan is over an image is shown of a circle with cross hairs. Within this circle there is a white blob that represents the bladder. This white blob is supposed to be centered in the cross hairs of the circle. My issue is that I got this post-scan white blob centered in the cross hairs at both 85 and 174 ml.
After I posted, I think I figured out somewhat what was going on. The pre-void residual of 240 ml was taken about ten minutes before. I figured it would still be fairly representative. But I was also testing the effect of a diuretic (two 300 ml cups of peppermint tea). Within the space of 80 minutes I urinated six times with five at 150 ml and one at 120 ml (typically urinating every 15 minutes or less). So the 240 ml was most likely not very representative. We had this discussion before, but I was surprised at how fast urine is added to the bladder even though peppermint tea has always made me pee a lot.
I looked at the training video again today. I think I need to be more careful on the pre-scan green outlines. I need to look for a good outline as well as the green vertical line being centered. Today, I noticed I was getting some pretty weird looking green outlines - one actually had an arm sticking out to the right that was quite long (never saw that before). Thanks for the reply.
Hank: I agree. I think it's useful in looking for changes over time. I'm trying to baseline and record my current LUTS with bladder scans and peak flowrate. That way I can see how things change 1 year, 3 years, 5 years..... down the road. To me it's better than saying to myself - "I'm pretty sure things have gotten worse, but not having any quantitative data to define how much worse (or with any luck better) is. I probably need to get a scan to calculate the size of the prostate. My uro estimates 40 cubic centimeters based on a DRE. He's probably close, but he had the same number 15 months ago as well. With scans I can hopefully see if it is changing over time.
I will have to look at the video again, but i think we are talking about the same thing with the green outline. Is that the ultrasound picture of the actual bladder? If so then the green outline has to conform to the actual bladder and if not you will not get an accurate measurment. In other words the machine is only going to measure what is inside the green line. With my 2D scanner I can adjust the bladder outline in cases for example where "an arm (is) sticking out". Did you see the video of the Portascan Plus? Is the pre-scan picture you're getting similar to the picture depicted in the Portascan Plus video? If so, that is a real time image of the bladder and again the green line should conform to it or your measurement will not be accurate. The reason I got the older Portascan Plus is because it allloww me to manually adjust the bladder outline if the machine doesn't draw it correctly. You can see that in the video as well. I didn't follow your peppermint tea example but you want to take a PVR with the scanner as soon as possible after your void, so ideally right away. If you wait say 20 minutes the kidneys could produce a lot of urine so you would be getting an inflated PVR with the scanner.
Jim
Jim
OK. I looked at the video again. So we're on the same page the one I looked at was on Youtube and called Portascan™ 3D Proper Scanning Technique Instructional Video" The voice ttrack sounded like a female robotic voice. Look at the 2;42 mark where it says "calculating". The dark (black) portion inside the green line is the bladder where the black is fluid. This green line should conform to the black shape (bladder) If it doesn't then the bladder volume will be incorrect because all the machine is doing is measuring volume within the green line. The cross hairs is simply an aiming device but again, what is inside the green outline is what will be measured regardless of what the cross hairs say. I think if you look at the video of my scanner as menioned earlier you will more clearly see how the measurement process actually works.
Jim