Siemens is a premier manufacturer of MRI technology, so people often question what the differences are between their models.

Here at DMS Health, we are often asked about two of their models – the Espree and the Avanto. Both are used in our mobile MRI units. Here we offer a look at how they compare:

Siemens Avanto vs. Siemens Espree comparison

First of all, there are many similarities between these two models, so let’s look at what is the same on each:

• Both systems feature 1.5T magnets.
• Both systems are based on the TIM (Total Imaging Matrix) platform running Syngo software VB19. TIM technology allows the technologist to exploit maximum SNR (Signal to Noise Ratio) and gain seamless head to toe imaging with a total FOV of up to 205 square centimeters (on the Avanto). This can be done without repositioning the patients or changing any coil.
• Gradients: The gradient systems on both systems are identical. They use XXL power stages capable of driving up to 40mT, however, the Espree is limited by software to 33mT gradient strength.
• Helium consumption: Both systems feature “zero boil-off”, meaning that only the relatively negligible amount of cryogen lost during coldhead and/or compressor service will need to be replaced.
• Coils and electronics: All other components, coils, and electronics are the same in these two models, with only minor differences in a few coils.

Bore size and magnet length

Essentially both cameras have very similar software, but where they differ is the hardware. The Espree has the larger, 70cm bore, while the Avanto has closer to 60cm. This makes the Espree more appealing for larger patients or any patients who are claustrophobic. Additionally, the Espree has 30cm of face space which is more comfortable for patients.

From the technologist’s point of view, just the fact of having that larger bore will mean that you can get through more examinations in any given time. The Espree is also a good choice when imaging patients with special needs like pain and mobility issues, respiratory problems and kyphosis.

With the shorter bore, you can also do more “head out” exams which tend to be very helpful for anyone who is claustrophobic. In fact, the Espree claims to be able to do this for over 60% of routine applications.

However, one thing that can be a limiting factor for the larger bore is its shorter magnet length. The Espree has a 125cm magnet whereas the Avanto has a 150cm magnet. This can mean a shorter maximum field of view in the head to foot direction for scanning on the Espree. There is software available to overcome these limitations, such as image merging where you can combine two images taken from different angles. If a technologist needs to merge different images, this can increase the time taken to complete a scan.

Besides exams of long bones or the thoracic spine where images may need to be merged on the Espree, both types of MRI machine will produce similar results in terms of quality of images.

There are more possibilities with interventional MRI and kinematic studies with the Espree, allowing clinics to broaden their patient base for the machine. For example, pediatric and elderly patients are also more comfortable with the wide bore and shorter magnet length.

Table weight limit

When you look at the limits placed on weight for the tables in their standard configurations, the Espree has a higher weight limit available than the Avanto. This won’t always be an issue as there are different configurations of tables available for the Avanto, however not all machines out there have the configurations allowing for higher weight limit.

Homogeneity

You get your best image quality with higher homogeneity. The Espree has a smaller area of homogeneity, or a smaller “sweet spot”, we could say. This means that image quality can be more challenging on certain types of exams, which is where the Avanto would have an advantage.

In terms of field of view (FOV) the Avanto has a 50cm FOV. The Espree has an elliptical FOV- 450mm x 450mm x 300mm. In addition to the Espree’s slightly smaller FOV, some users do not prefer the elliptical shape because it makes imaging outer anatomy like shoulders and breasts a little more difficult.

Channel density and RF amplifiers

In terms of channel density, both the Espree and the Avanto come in two basic channel density varieties – 32×8 and 76×18. The first number in this designator is the number of coil elements that can be read simultaneously. The second is the number of dedicated receiver channels. The most common Espree is the 32×8, with the 76×18 found in higher-end models.

Looking at RF amplifiers, he Avanto uses the DORA RF amplifier with a max output of 15kW.  The Espree uses the PORA RF Amplifier, with a max output of 22.5kW. If you’re considering parts availability, the PORA is rarer on the third-party market. The DORA is much more common and parts can be readily purchased from third-party parts suppliers.

Technologist familiarity with the machine

Both the Espree and the Avanto essentially operate the same way, so technologists could easily switch to one from the other without needing further training. In terms of mobile use vs. internal clinic use, the setup is the same too with the exact same magnet used.

Cost

The Espree is a little less common on the secondary market than the Avanto, although some machines can be found there. The Avanto will cost you less both brand new and on the secondary market.

Approximate MRI prices installed will vary based on whether you purchase an 8, 18, or channel system and software and coil configurations. The ranges below are the usual for each:
Siemens Magnetom Espree MRI:  $550,000 to $700,000
Siemens Magnetom Avanto MRI:  $450,000 to $600,000.

Final thoughts

Is one system better than the other? Both the Siemens Avanto and the Siemens Espree are high-quality machines offering versatile usability. Each has different nuances that might be considered an edge in certain areas.

For example, the wider bore of the Espree is valuable when working with obese patients or those who are claustrophobic. On the other hand, the Avanto has a longer magnet giving a greater maximum field of view.

It will come down to budget constraints and preference. Either machine would be a good choice.