· Major Hospitals Install fMRI Systems
· MRI for Neck and Spinal: A Discussion with Allen Rothpearl, MD
· New Technique for CCTA Lowers Radiation, Eases Concerns

Major Hospitals Install fMRI Systems

On December 17, Neurognostics Inc, Milwaukee, announced two new installations of its fMRI system: one at Hoag Memorial Hospital, Pasadena, Calif, and another at North Shore-LIJ Health System, New York. Neurognostics will provide the two institutions with data-acquisition hardware and workflow software, as well as the company’s library of stimulation paradigms designed to map an array of cognitive and motor functions. Both institutions boast dedicated neuroscience institutes focusing on brain tumors, epilepsy, stroke, and neurodegenerative disorders.

An fMRI system is an invaluable tool for hospitals with dedicated neuroscience institutes.

“Primarily, we focus on standardization of fMRI exams,” said Cathy Elsinger, PhD, Neurognostics’ vice president of research and clinical operations. “It’s difficult to integrate into the existing workflow of a radiology department. A lot of work has to be done by the MR technologist in the room, and there aren’t the components for measuring patient responses in a way that’s standardized. So we provide that standardization via some workflow software for the tech.”

The software works independently from the scanner to walk the tech through all the patient instructions and training, Elsinger says. “It’s all synchronized,” she explained. “It gives real-time feedback on how the patient’s responding, and that verification is great for lowering your risks. So it really does help. We spend about 4 to 8 hours training the techs, and then they’re good to go to administer these exams.”

At Hoag, radiologists will work with Neurognostics to research further paradigms. “By forming a collaborative relationship to develop disorder-specific tasks for our research use, we plan on taking full advantage of our advanced fMRI capabilities,” said Michael Brant-Zawadzki, medical director of radiology at Hoag. “We hope to replace WADA testing in our patients’ work-up for temporal lobe resection, and better guide brain tumor resection.”

The Neurognostics fMRI system also allows clinicians to integrate processed fMRI images into neuronavigation systems, enabling viewing of functional brain images both before surgery and in the operating room. North Shore University Hospital will be looking into clinical applications of Neurognostics’ current paradigms, according to Michael Schulder, MD, director of the Harvey Cushing Brain Tumor Institute and vice-chairman of neurosurgery at North Shore.

“Neurognostics’ fMRI system will standardize our ability to identify areas of functional activity prior to performing surgical resections,” he said. “Their ability to import fMRI images into our neuronavigation systems, including intraoperative MRI, is essential when applying fMRI to the clinical setting. We plan to study the clinical application of these paradigms and compare them to other, more labor-intensive methods of acquiring fMRI.”

Elsinger also cites the system’s expanded library of paradigms as a key benefit.

“We’re very forward-thinking in that we understand that presurgical mapping is where you’re seeing a lot of reimbursement now,” said Elsinger. “But this is a technology that’s growing, so we’ve been developing paradigms to test for disorders like ADHD. We think a lot of these applications will be used in a more widespread way in the future.”

Next, Elsinger says Neurognostics will focus on developing a solution for data processing. Currently the company offers a data processing service, with a turnaround time of 24 to 48 hours, but as institutions begin performing more and more fMRI studies, in-house processing will be more economically viable.

“We’re trying to understand who’s going to be doing the data processing from a workflow perspective,” said Elsinger. “We’re still gathering a lot of feedback on that. But this is a very exciting time for this technology. We’re only touching the tip of the iceberg now. A lot of new applications will arise.”

—Cat Vasko

MRI for Neck and Spinal: A Discussion with Allen Rothpearl, MD

Medical Imaging talked with Allen Rothpearl, MD, a board-certified general radiologist specializing in MRI, about the challenges associated with neck and spinal imaging as well as the latest MRI advances. In addition to being president of Complete Radiology Reading Services, a teleradiology reading company based in New York, Rothpearl is CEO of Jericho Specialty Imaging, a New Hyde Park, NY-based imaging facility specializing in outpatient pediatric and adult sedation for MRI.

MI: What are some of the typical neck and spinal applications of MRI technology?

Rothpearl: The most frequent application of MRI in the cervical spine (neck), thoracic, and lumbar spine, is the diagnosis of disk disease such as disk herniation. Pathologically, a disk herniation consists of a tear of the annulus fibrosus of the disk, which allows the soft inner portion of the disk, the nucleus pulposus, to escape and produce pressure or compression of the nerve roots or the spinal cord itself. Disk herniations can be associated with a clear insult to the spine, such as occurs during sudden deceleration injury like a car accident, or improper lifting of a heavy weight. However, a disk herniation can also occur with no specific clear-cut injury or precursor the patient is aware of. On the MRI, the actual tear can be seen, and the extrusion of the soft inner disk material is particularly well-demonstrated.

In addition to visualization of intervertebral disks, MRI is particularly good at imaging the spinal cord itself. Therefore, pathology of the spinal cord such as hematoma, neoplasm, and demyelinating diseases such as multiple sclerosis are best diagnosed using MRI. Because of its superior imaging characteristics with regard to the spinal cord and intervertebral disks, the MRI examination can be used to follow the progression of these diseases or assess the effects of treatment interventions.

In contrast to disk herniation, a disease such as scoliosis is best diagnosed using an x-ray examination, not by MRI.

MI: What are some of the unique challenges when using MRI specifically to image neck and spinal problems?

Rothpearl: A major challenge to the performance of spinal and other MRI examinations is that of claustrophobia. Claustrophobia can affect up to 15% of patients presenting for an MRI examination. Moreover, it can be a major factor in producing suboptimal or nondiagnostic MRI results. MRI imaging of children and infants also represents a significant diagnostic challenge. Because of the length of time and cooperation required to obtain diagnostic MRI images of the spine and other organs, pediatric patients can be difficult to image correctly. The issue of claustrophobia can be addressed by the use of open MRI units and/or patient sedation protocols, whereas oral or intravenous sedation with appropriate monitoring is the only way to obtain diagnostic spine MRIs in the majority of pediatric patients.

MI: What are the latest advances in MRI neck and spinal imaging, and how has technology evolved over the years?

Rothpearl: Neck and spinal imaging in particular has greatly benefited from the newer open MRI designs. Initially, when open MRI units came to the market they were known for poor image quality and were often thought of as inferior to the more mainstream closed high-field units. This has changed over the years, and the technology has now reached the point where software and microprocessor improvements have resulted in excellent image quality for most contemporary low- and midfield open MRI units. Furthermore, open designs no longer preclude using high-field magnets in the open MRI to produce images more akin to the closed high-field units.

MI: Is there a particular type of MRI you favor for specific applications, and if so, why?

Rothpearl: I favor open MRI designs for pediatric imaging. Open designs allow for easier sedation and monitoring of children. They also seem to be less daunting for many adult claustrophobic and nonclaustrophobic patients.

MI: Have you worked with the upright/standing MRI for neck and spinal imaging? What are the benefits of this technology?

Rothpearl: Upright/standing MRI units have most of the benefits of other open MRI units. Additionally, they allow for so-called “dynamic” spinal MR imaging. Dynamic imaging refers to the ability to image multiple views such as flexion and extension, in addition to more ubiquitous neutral views of the spine. Some clinicians favor these dynamic views for patients they send for spinal MRIs. Claustrophobic patients also seem to do well in the standing units.

MI: How does MRI compare with other modalities when it comes to image quality and accurately diagnosing neck and spinal problems?

Rothpearl: MRI is currently the gold standard for imaging and diagnosing disk and spinal cord disease. Image quality is not really the issue when comparing MRI to the other available imaging modalities for diagnosing neck and spinal diseases. The differences in the imaging modalities lie in what specifically is being imaged, and for what reason. For instance, to diagnose an abnormality such as a cervical fracture, I would recommend using CT with three-dimensional reconstruction over MRI because of CT’s superior imaging of bone structure compared to MRI.

MI: What’s next for MRI as it concerns neck and spinal imaging? Are you aware of any enhancements manufacturers are working on presently?

Rothpearl: Although still in its very early stages, ultralow-frequency MRI (so-called microtesla MRI) is a new technology that ultimately will likely produce a whole new generation of MRI units. However, in the near future, continued advances and improvements in microprocessor speed and image-processing software will continue to improve image quality, and also decrease examination times for low-, mid-, and high-field MRI units.

—Elaine Sanchez

New Technique for CCTA Lowers Radiation, Eases Concerns

Matt Budoff, MD, FACC, a preventative cardiologist based in Torrance, Calif, performs up to 10,000 to 12,000 scans annually on his patients, who represent a mix of people interested in cardiac health, those with heart disease, and others considering bypass surgery or stents. After a light was recently shone on the potential risks associated with CT, Budoff said his new patients have been particularly mindful of unnecessary radiation.

GE?s LightSpeed VCT-XT with Snapshot Pulse can capture images of the heart and coronary arteries in as few as five heartbeats.

Yet, their minds can rest easy, according to Budoff, who 2 years ago began using GE’s LightSpeed VCT-XT with Snapshot Pulse. The technology is said to reduce a patient’s exposure to radiation by 83% while capturing high-quality, accurate images.

“There’s been an increase in concern and awareness in radiation and exposure,” Budoff said. “We feel very comfortable using these scans because we are able to perform them at a dose that is a little bit more than what is used during a dentist checkup.”

The technology’s vast coverage, powerful x-ray tube, and maintenance fees and services were all considered in Budoff’s decision to utilize the VCT-XT. Covering a wide 40-mm slab in one rotation, the technology has the ability to capture images of the heart and coronary arteries in as few as five heartbeats. X-rays are turned on only during the required cardiac phase, and they are turned off completely at all other times. Essentially, the technique takes a complete picture of the heart using a series of three to four x-ray axial snapshots, which are taken at precise patient table positions and are synchronized with a specific phase of the cardiac cycle.

In order to guarantee high-quality arterial imaging, data acquisition must occur at the right heart phase. Predicting the R-wave’s timing accurately is critical because the system decides its move before the ECG signal of the next R-wave appears. SnapShot Pulse monitors this signal in real time, adapting the timing of scans by analyzing heart rate changes. In order to ensure high visibility of small vessels, and minimize density changes from one axial scan to the next, it is necessary for the contrast bolus to be caught at the time of maximum and steady enhancement.

To achieve the highest-quality diagnostic results in coronary CT angiography, there is a requisite for very thin slices and relatively high current. GE’s scanner addresses this necessity by reconstructing individual 0.625-mm images from the 64 detector rows. According to GE, its exclusive algorithms allow for accurate 3D volume reconstructions, and they ensure uniform performance across the detector array.

—E. Sanchez