RadiAnt DICOM Viewer - Discussion Forum
importing issues with a RadiAnt database located in an USB 3.0 key [resolved]

Jun 7, 2020 05:49 AM
by Tommy

Hello, I tried to set a RadiAnt DICOM database in a USB 3.0 thumbdrive.
The rationale is to have a portable database of DICOM cases that I can review both in my work PC and in my home laptop.

I tried importing DICOM cases either manually or using DICOM node transmission...

in both cases I frequently experienced freezing of RadiAnt during the transfer and incomplete importing of some images (i.e. in some sequences not all the images were imported)

I wonder if anyone else experienced this issues as well.

I confirm the USB is a 3.0 version and that was correctly plugged into a proper 3.0 port.

The USB thumbdrive is brand new and has a exFAT formatting (some computer geeks told me that is the best formatting in terms of copy-transfer) and I've already set "better performance" in the "policies" tab menu of the Windows 10 disk management...

I tried alto to "enable write caching on the device" but it was not supported by that thumbdrive.

Any idea how to improve the consistency and reliability of DICOM import into an USB-based thumbdrive database?

I came up with the theory that even if it's a 3.0 USB key, to number of files that are imported in a limited time causes a kind of overflow and freeze.... I wonder if it's possible to optimize the transfer, maybe limiting the average speed of transfer to allow the computer to keep the pace and complete a 100% copy of the images.
Jun 7, 2020 09:21 AM
by boskar
As far as I remember "better performance" means that data is physically written to the device during umounting/safe removal, until then it stays in your RAM, that's why the freeze due to overflow and possible data loss.

Try to change it, it will be slower, but should not freeze.
Jun 7, 2020 12:58 PM
by Tommy
basically I experienced the issue even when the "better performance" option was off by default...

so I made some research in the web and it seems that turning "better performance" on should have a positive effect in speeding up file transfer

however in the limited tests I made it seems there's no relavant difference between the 2 USB policies option status...

it seems that there's some bottleneck elsewhere...

probably during database import of a DICOM case, there's additional work needed to copy files and index them in the database at the same time while working on a USB stick (even if it's a 3.0)

there are no issue if the database is in the hard-disk but being on a USB stick probably disclose some performance issues...

maybe only the developer may tell me if my theory is right or wrong and if there's some workaround.

having a portable USB-based RadiAnt database would be a bless for moving cases from work to home and viceversa...

anyone else tried to do this trick with USB? is very easy to create a new database so I'd appreciate other users feedback about it
Jun 7, 2020 01:03 PM
by RadiAnt
When you open the RadiAnt archive, temporary database files are created in the database folder (*.shm, *.wal). These files can get pretty large. On SSD drives they speed things up substantially. However, on a slower USB flash, a slowdown can potentially be experienced. We will check this and probably add an option to disable these temporary files.
Jun 7, 2020 01:53 PM
by Tommy
thanks for your insight

as temporary workaround I will do this trick...

1- I'll create a classic dabatase on the SSD disk and load it with cases imported from the PACS

2- then I'll create ad empty database on the USB disk

3- using a file synchronization software such as PathSync I'll mirror the content of the SSD database in the USB disk

that way it would be just a question of file copy from SSD to USB and all the fuzz about temp files would be avoided

according to my tests any time I tried importing a DICOM case into the USB key, something went wrong... like freeze, incomplete import of some images etc. etc.

so in the current situation a direct USB based database is not technically functional...

better to use the file sync indirect method I described.

however, an optimization about a direct USB import of images should be considered... if these freeze/import issues could be resolved, this USB-portable database method would be an outstanding new feature...

I wonder if the temp files could be created in the SSD disk instaed of the USB key

Jun 13, 2020 10:30 AM
by RadiAnt
We made a few tweaks and fixes. Please check if the issues are gone with the latest RadiAnt DICOM Viewer 2020.2 BETA #16510
Jun 13, 2020 12:04 PM
by Tommy
made a fast test but it seems that importing into USB is kinda unstable...
cases keep being incompletely imported with missing images and I had freeze...

I'll test with a different USB key to see if the problem is about that particular key (is brand new though...)
Jun 13, 2020 12:07 PM
by RadiAnt
Are you importing from a PACS server/modality or some other source?
Jun 13, 2020 06:31 PM
by Tommy
Ok, I did some new tests this afternoon... I didn't find another USB key to test but I seems I've found where's the bottleneck...

I have a permanent PACS which is on a server in my network

RadiAnt is installed on a PC where I have an iQ-VIEW workstation that I use as a temporary archive and reviewing station for new cases.

If I try to import cases from the PACS into the USB key of the PC I always have issues... freezing or incomplete case download... sometimes the freeze not only affect RadiAnt but affect the whole computer so every app become unresponsive and I have to reboot the PC...

but, if I send the cases from the iQ-VIEW workstation to the USB-based database, the transmission seems smooth...

if my theory is correct, if the "sender" (in this case iQ-VIEW) and the "receiver" (RadiAnt) are on the same PC, the transmission is correct with no issues.

if instead the "sender" is another computer from the network all the flow of data has to pass trough the net, then reach the "receiver" computer and then be moved to the USB key... maybe too much traffic that impairs performance and reliability of the DICOM send job.

so it seems I have to send cases to the USB from the iQ-VIEW of the same PC where RadiAnt in installed and avoid download from a remote network server.

on the other hand if the RadiAnt database is on the hard-disk (I have an SSD) the import from the network is fast and reliable

so bottomline is:

- network to HD-based database is ok
- same PC to USB-based database is ok
- network to USB-based database is disfunctional

do you think my debugging is correct?

Jun 13, 2020 09:39 PM
by RadiAnt
Thanks for the extensive testing, Tommy. Yes, there are still some issues when importing from PACS to the database located on a (relatively) slow media. We should have a new beta version ready in a few days.
Jun 14, 2020 07:36 AM
by Tommy
it seems that if the transfer speed is too high and there are too many files to transfer the USB cannot keep the pace and causes freezing.

as said before, I tried a workaround to donwload cases into an HD-based database and then to synchronize that folder to a mirror folder in the USB drive

I used PathSync to do that... but I noticed that even the file synch had issues... it started at full speed then it often got stuck and started again after a variable pause...

I was able to overcome this issue applying a "speed limiter" to PathSync... it has an option that let's you limit the speed to 1MB/second... it's called "throttle"

this way the synchronization speed happen at a slower but constant speed and no issue of freezing took place...

a friend of mine who works in informatics told me that even if my USB is 3.0, having to transfer many multiple files from HD to USB impairs the performance...

if you have a single 1 GB file the copy and trasfer is smooth and can happen af very high speed but if you have 1GB made up of 10'000 files small files, the performance drops because of multiple "handshaking" operations that have to be done for each of those files.

so I think something similar happens with DICOM send and receive... many small files sent one ofter the other that need to be indexed into the database

probably this operation in impacted by the lower speed of USB (which even with USB3 is slower than a conventional HD) and the lower speed of network to USB transfer compared to HD to USB.

the mix of them causes RadiAnt to go crazy when importing cases from network to USB... so I wonder if you could workaround this just letting RadiAnt download the cases from the network to a temp HD folder and then from that folder to the USB

Jun 14, 2020 07:53 AM
by Tommy
another thing that I'd like to investigate is the possibility to handle case archiving as .zip files...

this way any case would be composed of a single .zip file achieving a minor drive space storage, a faster and more effective handling of downloading and uploading since it would be a single file with overall reduced size.

RadiAnt is already famous to be able to display zipped DICOM images with no performance glitch at all...

I wonder if such a thing could be done for archiving as well
I don't know if DICOM send/receive transfer can support zipped files or require pure uncompressed DICOM images...

however this should be somthing to consider... a proprietary system of archiving and dysplaying zipped DICOMS would be a "killer feature" that no other DICOM viewer has...

think about it.
Jun 17, 2020 03:59 AM
by Tommy
latest 16703 beta seems much better when importing cases from a DICOM workstation that's phisically located in the same PC.... I'm not seeing incomplete series import anymore

I still have to do more extensive testing about the PACS import from an external PC using the network which was the trickiest scenario
Jun 18, 2020 01:39 PM
by Tommy
a very brief update...

still not very efficient when importing from network to USB expecially if the network is busy with other DICOM transfers (even if they involve other DICOM softwares rather than RadiAnt)

I've alse experienced a failed import from CD-ROM to USB...
this is probably due to a combination of slow read from CD and write to USB

but at lease the HD to USB transfer works fine, better than in earlier betas...

so I'm happy about it
Jun 18, 2020 02:16 PM
by RadiAnt
Tommy, what do you mean by "not very efficient" import from network to USB?
Is it only slow, or images are missing, or anything else?
Jun 19, 2020 03:03 AM
by Tommy
I mean that some image are missing at the end of the transfer...

I will do more extensive testings in the next few days but as I said it seems that when the computer is dealing at the same time with other DICOM send/receive jobs the RadiAnt import from newtork to USB suffers somehow...

when I work my MRI constantly sends DICOM images to iQ-VIEW once a sequence is completed, so there's always a concurrent and constant flow of images from the network trough the hard-disk

my impression is that this concorrent DICOM job from another application has an impact on the performance of RadiAnt when importing from network to USB...
on the other hand import from network to the HD has no issue even if other softwares like iQ-VIEW are working...

but please, consider that this was just an impression... I'm working with a tight schedule so I couldn't properly retest the network to USB import

regarding the CD import I've only did one test... and it downloaded just a couple of sequences instead of the full case... again, this was done during a very congested moment with many applications opened so limited computer resources could have been played a significant role in it.

I wonder if there's a DICOM log or debugging option to monitor and record what's really happening during this transfers from the network... it could be interesting to benchmark how RadiAnt handles import during moments of calm (being the only application running) and moments of storm (other DICOM jobs running, multiple applications opened etc etc)

I have also to check if my PC is directly plugged to a LAN port or if it connects trough a switch...

in the latter case that could explain part of the issues which is only limited to network to USB transfer

as said before HD to USB is now robust and works fine event when the PC is very busy

Jun 20, 2020 08:34 AM
by Tommy
using latest beta 17017 I'm having issues with USB...

now transfer seems not very efficient either from network or from the same PC

a 250 MB case made up 533 images took almost 10 minutes to be imported in the USB3 database

transfer seemed fast at the beginning than speed started declining and progress bar got stuck for several seconds. at the end all the images were downloaded but at the price of and endless wait...

interestingly if I download the same case in the viewer it takes just a 1minute to complete and save the images in the temp folder which is based in the HD

in previous betas it seemed that the PC to USB database import was faster and only the network to USB was laggy... but this may be a false impression I had

actually both have the same bad performance...

the tests I did today were done in an optimal scenario... only the PACS and the PC were turned on and no DICOM-modality was generating traffic...

the PC is directly connect to the LAN with no switch in the middle.

another interest thing is that when I send a case from iQ-VIEW, it's send progress bar says 100% after a minute, whilst RadiAnt takes 10 minutes to reach the 100%... so the send has the same speed as usual, but the import finds a bottleneck somewhere.

Jun 20, 2020 09:26 AM
by Tommy
for the record here's the reply i got from an email by the devs


As for the imports from PACS to USB database.
This is how it works:

1) All images received from PACS are stored in the temporary folder on your hard disk.

2) Only then they are distributed to proper databases or viewers.

3) So you get fast confirmation of transfer in IQ view

4) But the transfer from HDD to USB continues and it only depends on the speed of USB

Anyway, there will be some logging added to RadiAnt to confirm the theory that it's only the fault of a slow USB.


so this explains why the DICOM sender software says the transfert is already over, whilst RadiAnt is still importing
Jun 22, 2020 08:10 PM
by RadiAnt
Right now we're waiting for the log files that could pinpoint the reason of your issues.

In our extensive tests on a multitude of USB flash devices (2.0/3.0/3.1) all PACS imports were completed without any missing images (although they were painfully slow on slower USB media, but this is how it goes when you place a database file on a drive with low IOPS numbers).
Jun 23, 2020 08:32 PM
by Tommy
just to know... which should be the the time I should expect that RadiAnt has to spend to import MRI cases that are composed by many small images?

I did a test right now

a 122 MB case made up of 1000 images... not a huge complexisive size but many small DICOM files to handle...

it took 3 minutes and 35 seconds...

is this an adequate speed or not, considering the limitations of an USB-based database you mentioned?
Jun 24, 2020 07:34 AM
by RadiAnt
MRI case: 1012 images, 356MB.
Database on USB Sandisk Extreme Pro 128GB.
Total time: ~10 seconds.
Jun 24, 2020 08:36 AM
by Tommy
my USB sucks
Jun 24, 2020 09:13 AM
by Tommy
I'll write a longer tonight regarding my misadventures with a chinese Netac USB3 key...

in the meantime I have a question... in the scenario of a portable database, who's gonna have a better transfer performance? a good quality USB3 key or a good quality USB3 external disk?
Jun 24, 2020 12:41 PM
by RadiAnt
I'd go with the high quality external SSD (like Samsung Portable SSD T5). Much better IOPS than pendrives.
Jun 25, 2020 03:07 AM
by Tommy
as said before I found that most of the issue were related to the poor quality of my USB3 key...

even if it was a brand new key it's just a cheap and unreliable Netac key

I was fooled by the low price, just 26 euros for a 256GB, but after benchmarking I figured out that the transfer of files has an inconstant and unpredictable speed... it's always very slow when dealing with multiple DICOM files of small size

that's why using it with RadiAnt had so many flaws.
my next tests will be performed on an external USB3 drive or from a professional USB3 key like Sandisk

bottomline is: never use RadiAnt on a cheap USB key

Jun 27, 2020 07:01 AM
by Tommy
here comes we reach the end of this issue...

as said in previous posts, the main issue was the bad quality of the USB3 key I was using (blame on Netac...)

now I'm using an external USB3 hard-drive (WD My Passport Ultra) and the speed and reliability of transfer is great...

even if it's not a SSD and not a brand new disk (I bought it 3 years ago) it's from a good brand and the performance is much better than a USB

probably a good quality USB3 key (i.e. Sandisk, WD or any other well known producer) could give an acceptable performance as well...

so bottomline is: if you wanna set a RadiAnt database on a portable device you should use hi-speed and hi-quality equipment...

so avoid old USB2 keys, beware of cheap USB3 keys and choose external USB3 disks (HD may offer a pretty good performance, whilst SSD will be like flying).

beware of cheap electronics... "buy cheap, buy twice"

Jun 27, 2020 05:29 PM
by Tommy
to give an idea of the perfomance of that WD MyPassport Ultra external HD I can tell you I moved a 290 MB case made up of 1822 images (DICOM lossless compression) from iQ-VIEW to the RadiAnt database in just 1 minute and 11 seconds.

that's not bad since that USB3 HD is a little bit old....
most important thing is that RadiAnt had no freeze or image loss
Jul 4, 2020 04:58 AM
by mark
Hi... i'm unable to import studies after windows update , kidly help

Post reply
Author (first name or pseudonym):


You have to accept cookies to be able to post messages.
Visitors can post messages on the forum without having to register. Please input your first name or pseudonym in the "Author" field. Do not publish any personally identifiable information (PII).

Please ensure you write your posts in English so that our international audience can understand and reply to your message.

The Administrator reserves the right to remove any messages that violate our forum rules; for example, those that are not related to the RadiAnt DICOM Viewer software, published in a language other than English, contravene regulations, etc.