MedWOW Explains Digital Radiology (DR)

Digital Radiology (DR) Replaces Standard X-Ray
Digital radiology (DR) may represent the top scientific breakthrough in medical imaging over the last ten years. The use of radiographic films in x-ray imaging might become obsolete in a few years, due to the superiority of digital radiology (DR). An appropriate comparison that is commonly understood is the replacement of standard film cameras with digital cameras. Images can be immediately acquired, deleted, modified, and subsequently sent to a network of computers, which is especially important in the medical field.

Benefits of Digital Radiology (DR)
The benefits from digital radiology (DR) are enormous. It can make a radiological clinic or department filmless. The referring physician can view the requested image on a desktop or a personal computer and often file a report just a few minutes after the examination was completed. The images are no longer held in a single location; but can be seen simultaneously by physicians who are miles apart. In addition, the patient can be given the x-ray images on a CD to take to another physician or hospital for consultation.

Advantages of digital radiology (DR) include time efficiency, as a result of being able to do without the standard chemical processing, as well as the ability to digitally transfer and enhance images. Being able to enlarge and highlight images is of paramount importance in x-rays, and digital radiology (DR) gives physicians and technicians better diagnostic tools, as a result. Also, less radiation can be used to produce an image of similar contrast, which is very important, especially in children and adolescents for whom it is important to keep exposure to radiation at a minimum.

MedWOW’s Digital Radiology (DR) Offerings
MedWOW, the multilingual, global medical equipment marketplace, features medical device inventories from dealers all over the world, so locating the specific digital radiography system or add-on you need from a variety of makes, models and manufacturers in a safe and protected environment, is easy and secure. MedWOW is the leading medical equipment portal for all types of medical equipment trade, and with over 12,000 users visiting the site daily; locating your particular digital radiography system or upgrade is a hassle-free experience. MedWOW also provides free Escrow service, so you can be sure you are getting exactly what you pay for.

Some of the digital radiography systems and add-ons currently available from imaging dealers throughout the world include: DIS Digital Radiography Upgrade Adapter #ezDR4000, RF System Digital Radiography Upgrade Adapter Naomi, DRTECH Digital Radiography Upgrade Adapter FLAATZ 330 and many more options.

Incorporating MRI Parallel Imaging Technologies

Advantages of MRI Parallel Imaging

MRI parallel imaging technology uses complex software algorithms to reconstruct the signals from multiple channels in a way that can reduce imaging times or increase image resolution, without the corresponding increase in imaging times associated with standard MRI scanner imaging. Although parallel imaging techniques have only recently been introduced into MRI scanners in hospitals and clinics, they have already achieved wide clinical acceptance in many imaging applications. Their considerable advantages in terms of better spatial and temporal resolution and enhanced image quality, have updated the position of MRI in a wide range of abnormality and disease imaging.

Multi-channel technology and parallel imaging allows for significant improvements in most clinical MRI scanner examinations. There is no significant degradation in performance, compared to non-parallel imaging. Faster scanning could increase the patient throughout, as well as dramatically improve patient comfort during scans.

This technology could potentially contribute to the use of MRI scanning as an alternative to CT scanning and play a significant role in radiation protection strategies, particularly in young patients.
MRI scanning offers superb soft tissue contrast. However, high- resolution scans are often excluded, due to long scan times. Parallel imaging offers much shorter acquisition times, while retaining the high resolution necessary for early lesion and/or tumor detection

Phased Array Coil System

MRI parallel imaging takes advantage of the numerous elements of phased array coil system. Each element of the coil system is associated with a dedicated radio frequency channel (a special single-channel radio receiver) whose output is processed and combined with the outputs of the other channels (signals acquired by the other coil elements). This technology improves the signal–to-noise ratio (the signal quality) as compared to a standard MRI scanner coil system; while covering the same explored body volume.

Multi-Channel Radio Frequency and Parallel Imaging

Multi-channel radio frequency and parallel imaging technologies are hardware and software implementations, respectively aimed at improving the coverage signal resolution and speed of MRI scanner examinations. With multi-channel technology, the MRI scanner signal used to form an image is collected by a collection of separate coil elements. Each element relays signal information along a separate channel to an image reconstruction computer. Such arrays of coil elements can improve imaging coverage and the ratio of signal-to-noise in the image. The number of elements in the array of detectors is an important factor in characterizing a parallel imaging system.

Multi-channel coil and receiving systems and parallel imaging technologies were first implemented in brain examinations. Recent developments in both hardware and software have allowed for broader clinical applications of these technologies, such as in cardiac, lung, abdomen, and limb studies. For example, parallel imaging, in partnership with multi-channel radiofrequency systems allows for better visualization of small lesions and blood vessels that may allow for an earlier diagnosis of cancer and cardiovascular disease. Greater imaging coverage is possible with multi-channel radiofrequency system technology facilitating oncology screening and peripheral angiography. Finally, scan times are considerably reduced using parallel imaging, allowing for tolerable breath holds when scanning patients. The most current MRI scanners at 1.5T and 3T all feature multi-channel radiofrequency system technology and parallel imaging.

Locating Parallel Imaging Upgrades on MedWOW

MedWOW, the global medical equipment marketplace, is a good place to look when you are ready to upgrade your imaging department by adding multi-channel technology and parallel imaging to your MRI system.

MedWOW features imaging inventories from dealers all over the world, so locating the specific MRI parts you need from a variety of makes, models and manufacturers in a safe and protected environment, is easy and secure. MedWOW is the leading medical equipment portal for all types of medical equipment trade, and with over 12,000 users visiting the site daily; locating your particular MRI parallel imaging upgrade is a relaxed experience.

Explaining the MRI Receiver

What is the MRI Receiver’s Role?

An RF MRI receiver is used to process the signals from the MRI receiver coils. Most modern MRI systems have six or more MRI receivers to process the signals from multiple coils. The signals range from approximately 1MHz to 300MHz, with the frequency range highly dependent on applied-static magnetic field strength. The bandwidth of the received signal is small, typically less than 20kHz, and dependent on the size of the gradient field.

A traditional MRI receiver configuration has a low-noise amplifier followed by a mixer. The mixer combines the signal of interest to a low-frequency IF frequency for conversion by a high-resolution, low-speed, 12-bit to 16-bit analog-to-digital converter (ADC). In this receiver architecture, the ADCs used have relatively low sample rates below 1MHz. Because of the low-bandwidth requirements, ADCs with higher 1MHz to 5MHz sample rates can be used to convert multiple channels by time-multiplexing the receive channels through an analog multiplexer into a single ADC.

With the introduction of higher-performance ADCs, newer MRI receiver architectures are now possible. High-input bandwidth, high-resolution 12-bit to 16-bit ADCs with samples rates up to 100MHz can also be used to directly sample the signals, thus eliminating the need for analog mixers in the receive chain.

What are the Basic Elements of an MRI Receiver?

The basic elements of an analog MRI receiver chain are a pre-amplifier, a one- or two-staged modulator, aquadrature-phase-sensitive detector, low pass filters, two second-stage audio amplifiers with variable gain, and two analog-to-digital converters. As a result, the MRI receiver is very similar to a conventional superheterodyne radio receiver.

What to Look for in MRI Receivers When Purchasing

When dealing with MRI scanner receivers, it is important to take a good look at the signal-to-noise ratio and the bandwidth. In general, a wider bandwidth includes more noise. Decreasing the bandwidth by a factor of 4 results in an increase in the signal-to-noise ratio by a factor of 2 (less noise in the image).

When decreasing the bandwidth, we gain a better signal quality. However, there are also some trade-offs:

• the chemical shift artifact increases.
• longer echo time (TE) means some reduction.
• longer echo time means that fewer slices can be fitted into the repetition time (TR) period.

In the signal-to-noise ratio however, the overall effect of the reduction of the bandwidth is an improvement in the signal-to-noise ratio.
The initial bandwidth of the MRI signal produced by the MRI scanner is a function of the special encoding readout gradient strength, and the chemical shift.

Where to Buy MRI Scanner Receivers

MedWOW, the global medical equipment portal, specializes in imaging equipment, including an impressive selection of MRI scanner receivers. Currently, there is a broad selection of MRO scanner receivers for both stationary and mobile MRI units from GE Healthcare, Siemens, Marconi, Picker and Toshiba. MedWOW’s revolutionary search engine allows you to browse their catalogue in a number of ways, so finding the MRI scanner receiver you need is a simple procedure. You can filter by manufacturer, make, model, condition, location, year manufactured, Seller’s business type and more. So, when buying or selling MRI scanner receivers, MedWOW is a good place to find a varied selection at competitive prices, as well as safe and protected transactions.

A Must-Read for Used MRI System Shoppers

Congratulations on making the wise decision to upgrade your imaging department or clinic by purchasing a used MRI system. Thanks to all of the hospital liquidation sales taking place all over the world, there are many MRI systems available to choose from. As this major piece of imaging equipment is so important and as the technologies change relatively quickly, it is smart to be well-read on the topic before you set out to purchase.

Before acquiring any new or used MRI system, it is important to take into consideration the following main technical points, compiled by MedWOW, in order to make the best decisions possible for your medical facility:

1. In most cases, it is a good idea to buy a name-brand MRI system. Not only will it be easier to find replacement parts, but if you would like to sell it in the future, an MRI system from one of the imaging industry leaders will be easier to sell.

2. The MRI system should be FDA-approved

3. The MRI system should comply with the IEC 60601-2-23 standard

4. The MRI system should comply with all Dicom 3.0 MRI working modalities

5. Consider the magnetic field strength of the MRI system: 1.5T ,3T or other. (1.5T is currently the most commonly accepted MRI magnetic field strength for general use).

6. Decide which bore diameter of the MRI system, 60 cm or the larger bore diameter, 70 cm is what you are looking for, keeping in mind that sometimes, the size of the useful volume of view and the image quality are lower with the larger bore diameter.

7. What is the maximum useful volume of view of the MRI system? (dimensions on Z axis and on X,Y axies).

8. What is the extent of the image degradation on the margins of the volume of view? (the margins may be specified in terms of the homogeneity of the magnetic field Or image linearity or quality).

9. What is the homogeneity of the magnetic field of the MRI system in the center? (should be, at least, better 1 ppm ) .

10. What is the stability of the magnetic field of the MRI system? (in terms of ppm/hour).

11. To what extent is the magnetic field of this MRI system shielded? It is necessary to check the contours of the 5 Gauss magnetic field strength.

12. Make sure that the magnet cooling block of the MRI system is efficient and in good condition.

13. At what rate does helium evaporate (e.g. in terms of liter/ month) and how frequently should helium in this MRI system be filled?

14. Is the MRI system you are considering well-protected from damages in the event of magnet quench?

15. What is the noise level of this MRI system (expressed in average dBA SPL) and what means are used to reduce patient inconvenience?

16. What MRI magnet length are you interested in? (shorter magnets are more convenient for the patient).

17. What are the specifications of the magnetic field gradient system? (coils and amplifiers) in Z axis and in X,Y axies:
i. Maximum amplitude of the field gradient (expressed in mT/m).
ii. Maximum allowable amplitude of the magnetic field gradient for
iii. 100% duty-cycle.
iv. Maximum slew rate of the magnetic field gradient (expressed in mT/m/ms).
v. Note: higher values make it possible to extend the range of the examinations and may increase the working speed.

18. Be sure that the MRI RF power amplifier is of good quality. Under some working conditions it is heavily loaded. Higher power ratings ensure better performance and higher reliability (recommended power rating is above 10 Kw).

19. What is the number of receivers? Keep in mind that better performance is obtained when each coil element is connected to a separate receiver. However, in some more economical configurations, a receiver may have several "inputs" and simultaneously accept more than one coil element.
Currently, 8 receivers seem to be the minimum demand. MRI systems with 32 receivers are very common, especially if parallel imaging mode is used).

20. Performance of the receivers should be examined carefully, as the possibility of wide-band reception (e.g. 1 mHz) is preferable. Low-noise figure is an absolute necessity. An efficient band-roofing filter will improve the overall performance of the MRI system.

21. Check if it is possible to operate the MRI system in parallel imaging mode. (operation in parallel imaging mode can save time or reduce the image noise).

22. When buying an MRI system, make sure to carefully look into what type of coils you need as coils are very expensive and the cost of buying replacement MRI coils should be taken into consideration.

23. We suggest ordering the basic coils necessary for the present tasks of the MRI system and in the future you can easily acquire more coils to extend the range of the examinations.

24. The computation power of the MRI system is a key issue. There are several tasks which are performed by the MRI computers:
i. System control: data acquisition, data storage and data communication.
ii. The performance capabilities of the computers determine the speed of data acquisition, processing time and local storage capabilities.

25. The MRI system operating console should be well-designed and user friendly.

26. The diagnostic work station should include best quality screens and it should be possible to display several clear images simultaneously.

27. There should be access to every modality and every existing program in the system.

28. Perfect RF shielding is an absolute necessity. "Faraday Cage" should be accurately designed and installed according to the IEC 60601-2-23 (2005-08) amendment.

29. External RF interference attenuation should be higher than 100 dB.


MedWOW features MRI Systems from all of the major manufacturers, including: Philips, Picker, GE Healthcare, Siemens, Toshiba, Hitachi and many others, so finding exactly what you need according to the above guidelines is an efficient and simple process. With over 600 complete MRI Systems and over 6,250 MRI parts currently featured through MedWOW’s comprehensive online catalogue ─ locating and buying your next MRI system is trouble free.