Friday, April 25, 2008

OsiriX Involved in 3-Way....
Fusion, that is

Image courtesy of

A long time ago, I posted a piece about a better way to link old and new CT's together. My thought was to mark at least two, and preferably more, landmarks on each study and have the computer morph the old study to match the new one.

Well, this product hasn't quite appeared as yet, but OsiriX has come up with something rather similar that allows the fusion of PET, CT, and MRI studies. As reported in AuntMinnie:

Using several pairs of reference points located in the area of interest, the OsiriX 3D application correlates anatomic landmarks from the CT element of the PET/CT scan (or SPECT image) with those of the MR scan. With these markers established -- a greater number of points may be selected for greater accuracy -- the program allows the user to realign the CT image with the MR image "in a matter of seconds," consequentially also combining the PET/MR information accurately, Ratib (Osman Ratib, chair of radiology and head of nuclear medicine at the University Hospital of Geneva) explained.

"Once you've done that, you can use the registration tool to create a new set of images that are perfectly aligned, and which you can manipulate and play with," he said. "It provides convenient and fast visualization and navigation capabilities across a large number of multimodality images, and, of course, it is free and runs on off-the-shelf software."

Why is this fusion a good thing?

"PET shows the extent of metabolically active tissue in tumors, while MR shows the tissue alterations and the spatial distribution of surrounding organs. Unfortunately, very often MR does not show the exact extent of tumors due to surrounding inflammatory reactions and edema. Therefore, image fusion of PET and MR is expected to provide significant information that is not obvious from the two modalities presented separately; this can increase the accuracy and therefore confidence in diagnosis," Ratib added.

"A three-way registration tool can provide clinicians and nonradiologists with a convenient way to review and localize focal abnormalities. That they can now interact and 'navigate' through these image sets rather than just rely on static prints provided by radiologists is a real improvement in clinical practice," Ratib concluded.

One minor problem for some of us: This program only runs on Macintoshs. I guess I'll break down and buy one sooner or later.


waikikiTed said...

Hi Doc!
I've been playing with OsiriX and think it's pretty interesting. I have downloaded their sample DICOM PET images, bur still can't seem to get a real accurate experience that reproduces a more full-featured PET/CT workstation review scenario.

In your playing with Osirix, would you just call this a typical PET limitation of PACS or am I just finding the right tool/option commands in OsiriX?

Just curious about your thoughts, I love following your opinions on this Blog!

Dalai said...

Sadly, Ted, I don't have a Mac, and I haven't tried OsiriX as yet. I will remedy that someday soon!

waikikiTed said...

Once ya get one, you'll be hooked. There's a certain "cool" factor about it.

Keep your eye out on the Apple Discount Store as with the new hardware refresh earlier in the month, you can get great deals on notebooks and iMacs right now.

Keep up the great work! Love the site!