High quality and fast scanning with Compressed SENSE at KCH

At Kurashiki Central Hospital (KCH) in Japan, the MRI staff is always looking for ways to improve image quality and to scan faster. As one of the goals of faster scanning, they mention improving the MRI examination for patients, for instance by reducing breath hold duration and overall scanning time. This can make it easier for patients to comply, which in turn benefits the imaging results. An additional aim is to gain time for the MRI technologists, to relieve the pressure of their high workload and to give them more time to attend to their patients.

When the staff at Kurashiki heard about Compressed SENSE, they were eager to learn about its capabilities, and what these could mean for their staff workload and patient comfort. KCH is a general hospital that scans approximately 110 patients a day using seven MRI systems. Compressed SENSE was first installed on their Ingenia 1.5T scanner. The staff quickly appreciated substantial decreases in scan times and decreases in breath hold requirements, without having to compromise on image quality.

According to Fukushima, the high spatial resolution desired in brain and spine, used to typically require quite long scan times, but now the speed provided by Compressed SENSE may be traded for increased spatial resolution when necessary.

“For several brain examinations we use Compressed SENSE for faster¹ scanning, using C-SENSE factors from 2.0 to 3.5 for 2D and 3D protocols (except EPI diffusion). High resolution sequences such as TOF and 3D usually take the longest, but with Compressed SENSE we obtain really good quality, even when using a higher C-SENSE factor for decreasing scan time as compared to images with SENSE.”

“In the 3D TOF MR angiography sequence, we decided to use a C-SENSE factor of 3.5, after carefully examining the quality of the inflow signal and the detailed structure of the cerebral blood vessels using this higher factor. Compressed SENSE also allows us to use more 3D sequences instead of 2D sequences, providing higher resolution and allowing us to perform reformatting (MPR) in different orientations,” says Fukushima.

The KCH team has already changed most of their Ingenia 1.5T spine ExamCards by incorporating Compressed SENSE into their 2D TSE, mDIXON TSE, FFE, and 3D sequences.

“Previously with SENSE, our 2D mDIXON TSE scans required relatively long scan times. But now, with Compressed SENSE, we have reduced these scan times while maintaining a high SNR, because the Compressed SENSE technology helps reduce noise,” says Dr. Koyama.

“Because the faster scanning with Compressed SENSE saves us time, we can sometimes add a sequence to obtain high quality spine images in the same time slot for confident diagnoses. And in cervical spine exams, a 2D sequence is sometimes replaced by a 3D protocol, which provides us more information as it can be reformatted in different orientations. Compressed SENSE allows us to easily add this 3D sequence in the timeslot,” says Fukushima

“Incorporating Compressed SENSE in common spine sequences, such as mDIXON, 3D SpineVIEW and eTHRIVE, can substantially reduce the scanning time of these sequences, while maintaining adequate spatial resolution, resulting in high quality, multiple contrasts, multiple orientations,” says Dr. Koyama.

“In addition, fast sequences generally make it easier for patients to stay motionless throughout the scans, so it also helps us in that way.”

Dr. Koyama says that he used to believe that high resolution MRI at 1.5T required long scan times, and SNR was low. “With Compressed SENSE, however, it is possible to acquire high quality images, even with higher Compressed SENSE factors, so in a quite short time.”

“In breast scanning, high resolution is important to help me identify very small mammary lesions, so, we need high spatial resolution in 2D T1- and T2-weighted images, as well as a short scan time. Compressed SENSE has allowed us to increase spatial resolution, which benefits our diagnostic confidence.”

Dr. Koshi Miyake, cardiologist, explains that scanning of patients with cardiac arrhythmia can be challenging, as scanning times can become very long due to the varying heart rate. So his most important motive to implement Compressed SENSE in cardiac MRI exams was to reduce the burden of breath holds for the patient, while maintaining high image quality. He hopes this can also help to reduce motion caused by the difficulty for patients to hold their breath.

“Compressed SENSE has now been implemented in all cardiac exams. Thanks to the acceleration, fewer breath holds are now needed, or breath hold times are shortened. This reduces the burden of the exam for cardiac patients, without affecting the quality of information required for cardiac function analyses,” he says. “Because it’s easier for patients to comply with the breath hold times”

“In our previous cardiac cine sequence, we were acquiring two slices during one breath hold. With Compressed SENSE, we increased this to four slices per breath hold. It is also possible to shorten scanning time using a C-SENSE factor 6 without sacrificing image quality.”