Scan faster* and have more time for advanced MRI techniques

The abbreviated MS protocol for brain is only around 9 minutes, so in case of suspected multiple sclerosis, one or two more advanced sequences may be added, such as PSIR (phase sensitive inversion recovery) or susceptibility-weighted sequences to help us make more confident diagnoses in these inflammatory cases.

“We used to have long examination times for certain types of patients, a few lasting more than 40 minutes,” says Dr. Savatovsky. “What is remarkable, is that now all these examinations are below 30 minutes, which opens up opportunity to add more sequences when needed. It’s really hard to keep a patient for more than 40 minutes in the scanner, but because we have now cut scan times by at least 10 minutes, we can add more sequences without making the exam too long. And this is where the new system helps us make a difference. Examples include our examinations for informing brain tumor classification or giant cell arteritis workup, or for intracranial wall imaging – so in patients where we need several advanced sequences or high resolution sequences.”

“We added three additional sequences in our brain neoplasm classification exam: a 3D SWI sequence, APT and ASL on top of 3D morphologic sequences, an isotropic DSC (dynamic susceptibility contrast) and multivoxel spectroscopy. I think that in patients that need a classification for brain mass, for example, we can provide a more detailed and confident diagnosis than before, allowing the clinicians to decide for either a medical workup if no tumor is suspected, or for neurosurgery as soon as possible if a neoplasm is suspected.”

“In multiple sclerosis patients, we increasingly include a multishot susceptibility sequence [3] in our routine cases, thanks to the shorter scan times. Our abbreviated MS protocol for brain is around 8 to 9 minutes, so we can ask for one or two additional sequences to visualize the central veins, or to get an additional contrast to better depict posterior fossa lesions. In cases of white matter lesions of unknown significance on FLAIR images, for example when we see high signal hyperintensities in the brain, we can add on more advanced sequences such as PSIR (phase sensitive inversion recovery) or susceptibility-weighted sequences to help us in distinguishing between MS and nonspecific or vascular abnormalities in these inflammatory cases.”

So, what is the actual impact of having more information and more diagnostic confidence? According to Dr. Savatovsky, “One of the indications I’ve seen where using Elition is most impactful is in patients with suspected giant cell arteritis. As an ophthalmologic hospital, we see many patients with suspected giant cell arteritis. Usually we were performing MRI to help us rule out an ischemic stroke, and to verify that the supra aortic vessels are undamaged. With Elition, we still do this, but now we can add on more detailed high-resolution black-blood sequences on superficial arteries. This provides us with high confidence levels for diagnosis of giant cell arteritis (GCA) and as a result, some patients are not sent for a biopsy anymore. A patient who has a normal MRI will not require a biopsy and can be discharged from the hospital in the same day. Before, such a patient would have to stay for about a week, just to find that their biopsy results were negative. We have at least three or four patients a week with suspected giant cell arteritis. For a great deal of these patients we can have a direct impact on their hospital stay.”

Dr. Savatovsky recognizes that throughput in an MRI center not only depends on scanning time, but also on the time needed by the technologist to position the patient and operate the MRI scanner. “Scan time in very short exams will last from 5 to 9 minutes. Our goal is to keep our average scan time under 15 minutes.”

“The time needed for positioning the patient and the technologist’s workflow depends on the device. We particularly benefit from the lightweight FlexTrak dockable patient transport system for patient preparation outside the MRI room, which we purchased with the Elition. Currently, patient positioning is quite fast, even for heavy or bedridden patients, because with FlexTrak the patient and coils can be installed in the preparation room and then be brought into the scanner room immediately after the previous examination ended.” Other Elition features that support a fast workflow include the auto-start function that starts the scan as soon as the technologist closes the scanner room door.

“The fast scanning capabilities that came with Elition allow us to do a really quick examination and answer a lot of questions within a short time."

Dr. Savatovsky appreciates the improvements and flexibility that Elition with Compressed SENSE and MultiBand SENSE provides, particularly for stroke patients. “For stroke, it allows us to cut about 5 minutes off of our stroke protocol, or to keep the same acquisition time and get more insights.”

The ability to perform more sequences can help in making a swift and confident diagnosis. “For example, our stroke cases usually include the regular sequences that every center does (b1000 diffusion, FLAIR, time-of-flight angiography), but we also image supra aortic vessels, and we can replace a gradient echo sequence with a fast 50-second susceptibility-weighted sequence, and all of this doesn’t add much time. because all the regular sequences are accelerated on Elition.”

“The time savings with Compressed SENSE and MultiBand SENSE make it easier to add sequences to give us additional insights. Depending on the context and the first results, we might add a DSC perfusion to assess the ischemic penumbra, an ASL perfusion to help find an alternative cause in case of normal diffusion, or add a high-resolution T1 sequence for a stroke patient, to quickly assess wall imaging in emergency cases. The additional sequences can help improve patient management, because we can already consider some alternative diagnoses if the morphological MRI is normal.”

Using MultiBand SENSE allowed the staff to improve their diffusion quality. “Our diffusion sequence was already fast before, about 40 seconds. Now with Elition, it still lasts 40 seconds, but we improved the spatial resolution by 0.2 mm and use high b-values to be more sensitive to visualize changes related to acute stroke,” says Dr. Savatovsky.

“We now also developed a high resolution DTI sequence (1.3 x 1.3 x 2 mm) that can be reformatted and takes 2 to 5 minutes depending on the coverage. We use it every time we have a doubt, or when we expect the diffusion to be abnormal but don’t see that on the fast sequence. We occasionally spot small ischemic infarctions that would not have been visible with the regular diffusion sequence.”

Looking for inflammatory lesions of the spinal cord is usually challenging with MRI, says Dr. Savatovsky. “We solved some of the challenges by implementing sequences such as 3D PSIR, which allows us to see far more lesions than the usual T2 imaging. We are starting to see cases where the MRI images at 1.5T were normal, but then we do see lesions when performing the PSIR at 3.0T.” [1]

“Elition also performs very well in imaging of the bony spine, the discs and degenerative disease, especially now that we can include at least one 3D sequence in every scan. For example, we perform a lot of 3D spin-echo (TSE) sequences when imaging degenerative lumbar spines. Thanks to Compressed SENSE and the 3D SpineVIEW protocols, we have a very high signal intensity with no flow voids, so the image quality is very good. The possibility to reformat the images in every plane raises the diagnostic confidence, especially in patients who have to undergo surgery.”

Previously, about 30 patients a day were scanned on their Ingenia, 3.0T, during a 15-hour opening period. With the Elition system, the average number of patients scanned per day increased by approximately 10%. “On a day where we only scan outpatients, we can scan 35 to 40 patients a day. Also, routine MRI cases, such as IAC, headaches workup, memory impairment, acute neurological deficit, and multiple sclerosis, last less than 15 minutes, which is appreciated by patients who prefer short examination times,” says Dr. Savatovsky. “Elition really makes a difference. For example, sequences that lasted 6 minutes a few months ago are now completed in 3.5 minutes.”