Utilization of Low-Field MR Scanners

Hayashi, Naoto; Watanabe, Yasushi; Masumoto, T.; Mori, Hiromu; Aoki, Shigeki; Ohtomo, Kuni; Okitsu, Osamu; Takahashi, T.

doi:10.2463/mrms.3.27

Cited by 57 publications

(85 citation statements)

References 47 publications

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“…Because of its superior performance, the technique is also expected to be applied to interventional MR imaging and other applications utilizing an open MR system. 8,9 The slice position determined by ISC can be used for other kinds of scans with high spatial resolution. Figure 11 shows coronal-plane and sagittalplane images of the knee, in which the meniscus and the ligaments are clearly shown.…”

Section: Discussionmentioning

confidence: 99%

Interactive Scan Control for Kinematic Study in Open MRI

et al. 2007

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Purpose: A tool to support the subject is generally used for kinematic joint imaging with an open MRI apparatus because of di‹culty setting the image plane correctly. However, use of a support tool requires a complicated procedure to position the subject, and setting the image plane when the joint angle changes is time consuming. Allowing the subject to move freely enables better diagnoses when kinematic joint imaging is performed. We therefore developed an interactive scan control (ISC) to facilitate the easy, quick, and accurate setting of the image plane even when a support tool is not used.Methods: We used a 0.4T magnetic resonance (MR) imaging system open in the horizontal direction. The ISC determines the image plane interactively on the basis of ‰uoroscopy images displayed on a user interface. The imaging pulse is a balanced steady-state acquisition with rewound gradient echo (SARGE) sequence with update time less than 2 s. Without using a tool to support the knee, we positioned the knee of a healthy volunteer at 4 diŠerent joint angles and set the image plane through the patella and femur at each of the angles. Lumbar imaging is also demonstrated with ISC.Results: Setting the image plane was easy and quick at all knee angles, and images obtained clearly showed the patella and femur. Total imaging time was less than 10 min, a fourth of the time needed when a support tool is used. We also used our ISC in kinematic imaging of the lumbar.Conclusion: The ISC shortens total time for kinematic joint imaging, and because a support tool is not needed, imaging can be done more freely in an open MR imaging apparatus.

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Section: Discussionmentioning

confidence: 99%

Interactive Scan Control for Kinematic Study in Open MRI

et al. 2007

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“…Intraoperative imaging was performed with 0.4-T MRI (AP-ERTO Inspire, Hitachi Medical Co., Chiba, Japan) [8]. The running costs of a non-superconductive low-field MRI such as this scanner show a cost advantage [9]. In addition, the low-field MRI with a narrow 5-gauss line does not influence the devices used for surgery.…”

Section: Methodsmentioning

confidence: 99%

Skin shift and its effect on navigation accuracy in image-guided neurosurgery

Mitsui

Fujii

Tsuzaka

et al. 2010

Radiol Phys Technol

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Neuronavigation systems have been developed for image-guided neurosurgery to aid in the accurate resection of malignant brain tumors. Therefore, the accuracy of the neuronavigation is important. However, many factors can reduce the navigation accuracy during surgery. Before craniotomy, the patient's head is secured to a head frame with head pins; this fixation may cause displacement of fiducial markers and reduce the accuracy. We term this phenomenon skin shift. In this study, the extent of skin shift and its effect on navigation accuracy were determined by use of both preoperative magnetic resonance imaging (MRI) scans acquired before fixation and intraoperative MRI scans acquired after fixation. We measured the displacement of the fiducial markers by using fusion images obtained by integrating preoperative and intraoperative MRI scans. We also evaluated the navigation accuracy of registration based on preoperative and on intraoperative MRI. The mean (± SD) extent of skin shift was 5.34 (± 2.65) mm. The navigation accuracy of registration based on preoperative MRI was 4.06 (± 2.25) mm, and that of registration based on intraoperative MRI was 2.51 (± 1.32) mm. No significant correlation was observed between the extent of skin shift and the distance between the head pins and fiducial markers (p > 0.05). The navigation accuracy of registration based on intraoperative MRI was significantly higher than that of registration based on preoperative MRI (p < 0.001). The results indicated that skin shift was caused by the fixation, and that this shift reduced the navigation accuracy. Intraoperative MRI can correct the effect of skin shift.

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“…Iron oxide particles are strong contrast agents and are typically detected by the way they shorten the NMR signal and darken the images [47,48]. While this approach has proven useful in tissues that are rich and relatively uniform in proton concentration, it is not a viable solution for the lung, which has inherently low intensity and thus darkened areas in all airways and alveoli [49][50][51].…”

Section: Mri Of Drug Delivery Systemsmentioning

confidence: 98%

Image-guided drug delivery in lung cancer

Wiedmann

Sadhukha

Hammer

et al. 2012

Drug Deliv. and Transl. Res.

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Lung cancer continues to be the number one cause of cancer-related deaths in the USA. Early identification of the disease, availability of more effective drugs, and improved delivery of such drugs specifically to cancer cells are needed to decrease lung cancer-associated morbidity and mortality. The concept of image-guided drug delivery (IGDD), which envisions the utilization of imaging techniques for quantitative assessments of tumor-targeted drug delivery and therapeutic response, has the potential to make a significant impact in lung cancer. While the anatomic and physiological features of the lung pose distinct problems for imaging drug delivery, several new techniques are emerging that have the potential to overcome these problems. X-ray is a routinely used technique for diagnosing lung cancer; however, positron emission tomography (PET) and magnetic resonance imaging (MRI) are complementary approaches. PET- and MRI-based techniques (such as functional MRI) offer the possibility of imaging the delivery of specific molecules to cancer tissues in the lung. This paper reviews fundamentals of imaging with an emphasis on MRI and to some extent PET, since it will be argued that these techniques are the most promising for development in IGDD for lung cancer. Finally, key literature contributions will be highlighted, which exemplify the current successes in this area.

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Utilization of Low-Field MR Scanners

Cited by 57 publications

References 47 publications

Interactive Scan Control for Kinematic Study in Open MRI

Interactive Scan Control for Kinematic Study in Open MRI

Skin shift and its effect on navigation accuracy in image-guided neurosurgery

Image-guided drug delivery in lung cancer

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