Renal imaging at 7 Tesla: preliminary results

Abstract

The results demonstrate the feasibility and diagnostic potential of dedicated 7T renal imaging. Further optimisation of imaging sequences and dedicated RF coil concepts are expected to improve the acquisition quality and ultimately provide high clinical diagnostic value.

7 Tesla MR Imaging: Opportunities and Challenges

“…One of the most challenging factors of ultra-high-field imaging is related to the increased power deposition in human tissue, which is characterized by the Specific Absorption Rate (SAR) [6 -8, 22, 23]. Energy deposition is known to increase with the square of the magnetic field [24]. Hence, the acquisition of RF-intense turbo-spin-echo (TSE) and fat-saturated sequences may be impaired in high-field MRI.…”

“…This is caused by the shortening of the wavelength, decreasing from 52 cm at 1.5 T to 12 cm at 7 T, which causes impeding standing waves or dielectric effects. Hence, RF shimming becomes crucial when a larger FOV is imaged [22,24,25,27]. In an attempt to overcome impeding B 1 field inhomogeneities, different shimming techniques have been introduced for 7 Tesla body imaging.…”

“…In an attempt to overcome impeding B 1 field inhomogeneities, different shimming techniques have been introduced for 7 Tesla body imaging. Specific circularly polarized modes have been applied for abdominal MRI [24,25,27] and individual RF mapping for female pelvis imaging [28] with successful reduction of impeding inhomogeneities and minor residual limitations. Orzada et al proposed another dedicated shimming technique by the name of TIAMO (Time-Interleaved Acquisition of Modes) [29,30].…”

“…Hence, the application of optimized sets of amplitude and phase shifts to achieve uniform excitation of dedicated body regions becomes possible [57]. The successful clinical implementation of this add-on system has been demonstrated in various abdominal trials [24,25,27] Fig. 6).…”

Development and evaluation of a small and mobile Magneto Alert Sensor (MALSE) to support safety requirements for magnetic resonance imaging

“…MRI accidents are listed as number 9 of the top 10 risks in modern medicine [1][2]. With the advent of (ultra)high field MR systems [3][4][5][6][7][8][9][10][11][12][13][14] this risk, which is commonly known as the missile or projectile effect is even more pronounced. These projectiles usually consist of common office and hospital items that contain a fair amount of ferromagnetic metal including for example hospital beds, intra venous poles, oxygen tanks, and conventional ECG devices used for patient monitoring, computer displays, ventilator etc.…”