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imaging is everything

From STORAGE Magazine Vol 7, Issue 4 - June 2007

Leading-edge imaging equipment is providing radiologists with ever more detailed images of their patients. And storage technology is flexing its own muscles to handle the vast quantities of data this generates

Twice the capacity at one half the price. Those kinds of numbers fundamentally change how diagnostic radiology centres serve their patients and improve patient care, while lowering their overall costs to deliver their services. To recognise these benefits, some radiology centres are starting to use new, lower-cost storage systems to store the increasing number of larger size, higher-resolution images the latest Magnetic Resonance Imaging (MRI) systems produce.

On-going improvements in MRI technologies continue to provide radiologists with ever more detailed images of their patients. Images produced by the newest MRIs reveal nuances in shadow that allow radiologists to determine precisely where a problem resides and establish what is the nature of the patient's problem.
The hidden downside associated with using higher resolution images is that they demand more storage to house the larger image files generated. Each two-dimensional cross-section, or slice of tissue, generated by an MRI produces an image that can range from hundreds of kilobytes to megabytes in size.

These increases most adversely impact the storage requirements for specialised diagnostic radiology centres such as Manhattan Diagnostic Radiology (MDR), which generate many thousands of MRI images each day. Taking about 400 pictures for each study they perform - compared to 16 pictures for the average hospital - storage requirements for each MDR study can easily reach from 100 MB to 1 GB.

"We see on average about 300 patients a day," says MDR's IT director Joe Gomez, "so our radiologists need to create thousands of MRI images daily that consume anywhere from three to three hundred gigabytes of storage space daily."

To keep costs down, MDR used medical grade 9.6 GB DVDs to store archived data, at a cost of $18 per DVD. However, not all DVDs could be stored in their Plasmon DVD jukebox and, with as many as 13 doctors using the system at any one time, technicians had to retrieve DVDs that contained the images associated with archived case studies and insert them into the jukebox. Retrieval times could take anywhere from 15 to 30 minutes per DVD to complete.

These delays were negatively impacting the ability of MDR's radiologists to access and view patient studies, and complete the diagnosis of their patients in a reasonable timeframe, so MDR began to evaluate alternative storage methods for storing archived case studies. They had twice looked at using disk systems in the past 36 months and again MDR considered this option. Only this time it widened the net, in terms of potential storage providers it might be willing to entertain as potential candidates.

Features that MDR's Gomez did not wish to compromise on were the integrity or availability of the storage system. A self-described "belt and suspenders" type of guy and "EMC fan", Gomez knew disk prices had dropped dramatically, but did not wish to risk bringing in another vendor's new storage system, if it would in any way adversely affect the quality of service he provided to either his radiologists or MDR.

Amongst vendors from whom Gomez requested a bid was Nexsan Technologies, which had been mentioned to him by an IT director at another diagnostic radiology centre. Working with Nexsan channel partner RADirect on the bid, the quotes he received back stood in stark contrast to one another. One storage array was priced at $130,000, he reports, while a similarly configured Nexsan SATABeast storage array containing 21TBs cost less than $60,000.

For Gomez, Nexsan's quote represented a significant savings that also delivered twice the storage capacity. Recognising that Nexsan would allow him to keep both his primary and archived data online, while eliminating or at least minimising the need for DVDs, Gomez still needed to compare the performance, availability and reliability of the SATABeast to his existing system for his production data.

To test the Nexsan SATABeast system, Gomez initially ran both the existing and Nexsan storage systems side by side with the same production image files on both. Gomez's users almost immediately witnessed a small percentage performance gain using the SATAbeast. "While five to ten per cent is not a lot," Gomez acknowledges, "with thirteen doctors accessing the system at the same time, even small incremental improvements in performance add up."

Another concern of Gomez was the reliability of the disk drives used in the Nexsan storage system. Using the same SATA disk drives as found in many PCs, Nexsan's use of these drives initially caused Gomez some concern about their reliability. But during testing, and afterwards in production use, Gomez has not experienced a single disk drive failure.

Nexsan Technologies VP of marketing, Brendan Kinkade, finds Gomez's positive experience with SATA drives a common experience. "Enterprise SATA drives now include five-year warranties, are rated at over one million hours MTBF [Mean Time Before Failure] and share many of the design features and components of more expensive Fibre Channel disk drives," he says. "With the new generation of SATA drives, we have seen overall failure rate of less than 0.5 per cent across thousands of systems in the field."

One unexpected benefit that Gomez realised when testing the SATAbeast was its smaller footprint on MDR's data centre floor. Though this feature was not a deal maker, Gomez points out, "in Manhattan, every square inch of space you save is valuable".

The main problem Gomez had with Nexsan SATAbeast was that its cooling fans were very noisy - so much so that Gomez requested that Nexsan reprogramme the storage system's software to cause the fans to run more slowly in order to reduce the noise. However, once testing was completed and the technical bugs resolved to Gomez's satisfaction, MDR made a complete switch from its existing vendor to Nexsan for both their primary and archived stores of case study image files.

The improvement in performance, coupled with the availability of higher storage capacities, has elevated the effectiveness of MDR's diagnostic radiology practice. By keeping all production and the majority of archived images online, retrieval times for images in a patient study are now often measured in seconds or minutes, thereby reducing the amount of time doctors need to spend waiting for patient study images and allowing them to be more productive in their jobs.

Gomez says the first Nexsan storage system he has purchased is already full, but that he plans to buy more. The savings generated, coupled with the additional capacity, is allowing him to perform tasks previously only dreamed of. Short term, he plans to buy more storage capacity for his production site and also set up a Nexsan SATABeast at an offsite location to mirror MDR's data in real time.

"Bottom line, we are lowering our cost per study and are able to store larger amounts per study," Gomez concludes. "MDR, doctors and patients are now being better served, because of this change in back-end storage." ST