From strength to precision: A systematic review exploring the clinical utility of 7-Tesla magnetic resonance imaging in abdominal imaging

Table 1 Overview of studies evaluating abdominal organs with 7T-magnetic resonance imaging

Ref.	Study Design	MRI model, RF Coil & Imaging Parameters	No. of patients	Endpoints/Applications
Fischer et al[17], 2014	Prospective study	Siemens Terra: 8-channel transmit/receive body coil; T1w 2D FLASH TOF MRA; transversal orientation; TR = 17ms; TE = 4.7 ms; TA = 0:33 s	12	For non-enhanced MR imaging of the arterial, venous and portal liver vessels in candidates for hepatectomy or liver transplantation with acute or chronic renal insufficiency
Traussnigg et al[20], 2017	Prospective Non-randomized feasibility study	Siemens Terra; surface coil (1H/31P, 10 cm diameter, Rapid Biomedical GmbH), 2D 31P-MR CSI sequence, TA = approximately 10 min	30	As a non-invasive tool for obtaining pathomechanistic insights to improve risk stratification using changes in energy metabolism including dynamic ATP flux in inflammation and fibrosis in non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH)
Beiderwellen et al[28], 2017	Prospective study	Siemens Terra; 8-channel transmit/receive body coil; T1w 3D spoiled gradient-echo VIBE sequence; coronal; post-contrast; TR = 2.90 ms; TE = 1.09 ms; TA = 27s; Resolution = 1.25 mm × 1.25 mm × 1.6 mm	10	For Gadobutrol dose reduction (to 0.025 mmol/kg of body weight) while maintaining diagnostic image quality for the diagnosis of renal artery stenosis in patients with renal impairment
Purvis et al[21], 2017	Prospective study	Siemens Terra; 16-channel 31P RF array heart/liver butterfly-loop coil pair; 3D UTE CSI sequence; TA = approximately 28 min	26	For studying metabolism in liver disease
Wu et al[30], 2010	Pilot study (ex-vivo)	Siemens Terra; T2w TSE and PRESS with CHESS water suppression; TE/TR = 30/1700 ms; resolution = 3 mm3 isotropic; TA = approximately 23 min; MRS data processed using NMR Software Nuts (Acorn NMR Inc., Livermore, CA, United States)	N/A	To construct a malignancy index based on prostate cancer metabolomic profiles
Rosenkrantz et al[33], 2015	Feasibility study	Siemens Terra: Axial TSE T2w sequence; TR = 11670 ms; TE = 80 ms; FA = 160; Resolution = 0.75 mm × 0.75 mm × 3 mm; BW 254 Hz/voxel; NEX = 1	3	For tumor localization using T2w MRI at 7T before prostatectomy
Luttje et al[32], 2014	Feasibility study	Siemens Terra: 2D 1H MRSI grid positioned in the tumor location as seen, 3D 31P MRSI grid positioned over whole prostate; TE/TR = 56/2000 ms; resolution = 5 mm × 5 mm × 5 mm; TA = 448s; 3D 31P MRSI TE/TR = 0.42/200 ms; FA = 20°, resolution = 12 mm × 12 mm × 12 mm, TA = 610s	5	To acquire both 1H and 31P MRS within the same scan session in patients with prostate cancer
Lagemaat et al[35], 2015	Prospective study	B0 and B1+ field-mapping to optimize B0 and B1 field homogeneity in the prostate; T2wTE = 71 ms; TR = 3000–3640 ms; resolution 0.75 mm × 0.75 mm × 3 mm with overlaid 2D 31P T1 3D 31P MRSI Nuclear Overhauser Effect (NOE) measurements	12	Optimization of phosphorus (31P) MRSI of the human prostate at 7 T by the evaluation of T1 relaxation times and the NOE of phosphorus-containing metabolites
Vos et al[31], 2014	Prospective study	Siemens Terra; 8-channel TxRx body array coil + an endorectal coil tuned to the P31 frequency; Axial/sagittal T2w FSE TR = 3000/3640 ms; TA = 90/113s	17	Prostate cancer is visualized on T2-weighted MRI with periprostatic lipids appearing hypo-intense compared to healthy peripheral zone tissue
Durand et al[34], 2017	Feasibility study (ex-vivo)		N/A	To determine high-resolution ex-vivo MRI protocol parameters for characterization of prostate tissue at histological length scales
Philips et al[36], 2019	Pilot study	Siemens Terra; Combined 31P Tx/Rx and 1H Rx endorectal coil (31P/ 1H ERC), 8-channel external multitransmit 1H array; T2w TSE, resolution 0.43 mm × 0.43 mm × 3 mm; TA = 119s; DWI EPI (RESOLVE) b0, b100, b400, and b800, resolution 1.75 mm × 1.75 mm × 3 mm, TA = 274s; 31P 3D MRSI with non-selective BIR-4 excitation, TA = 789s; 1H MRSI PRESS TA = 421s	4	To perform high resolution multiparametric MR imaging and 1H and 31P spectroscopy of the prostate using a 31P Tx/Rx 1H Rx endorectal coil in combination with an external multitransmit 1H body array
Hahnemann et al[37], 2016	Prospective comparative study	Siemens Terra; custom-built 8-channel Tx/Rx RF body coil with B1+ shimming; coronal bSSFP resolution 0.8mm × 0.8 mm × 2.0 mm, TA = 26s; axial bSSFP, resolution 0.7 mm × 0.7 mm × 2.0 mm, TA = 20s; coronal T2w HASTE, resolution 1.0 mm × 1.0 mm × 5.0 mm, TA = 25s	12	To perform non-enhanced high quality T2w MRI of the small bowel
Gajdošík et al[22], 2014	Prospective study	Siemens Terra; 10 cm diameter Tx/Rx surface coil (Rapid Biomedical GmbH, Rimpar, Germany); STEAM sequence; resolution 30 mm × 30 mm × 30 mm	11	To assess the proton T1 and T2 relaxation of in vivo hepatic water, choline and lipid metabolites with possible J-coupling behavior of lipids in healthy volunteers
Pang et al[15], 2011	Pilot study	bisected microstrip transceiver surface coil; SSFP sequence; TA < 20s	-	For liver imaging
Cervelli et al[23], 2022	Feasibility study (ex-vivo)	GE Signa; 8-channel Tx/Rx knee RF coil; morphologic sequences: 3D-T2w-CUBE, IDEAL T1w and T2w, 2D- and 3D-MRCP; Quantitative sequences: MP2-RAGE, MSE, IDEAL, 2D-MRF	N/A	For differentiating between tumour and non-target pancreatic tissue using conventional T1w-, T2w- sequences and MRF-derived relaxometry. The MRF sequence obtained reliable relaxation time data
Umutlu et al[24], 2011	Prospective study	Siemens Terra; a custom-built 8-channel Tx/Rx RF body coil; 2D FLASH, resolution = 0.8 mm × 0.8 mm × 2.0 mm, TA = 31s; 3D FLASH, resolution 1.3 mm × 1.3 mm × 1.6 mm, TA = 27s; IP and O/P GRE, resolution 1.1 mm × 1.1 mm × 3 .0 mm, TA = 20s; bSSFP, resolution 1.3 mm × 1.6 mm × 4.0 mm, TA = 19s; T2w TSE, resolution 1.4 mm × 1.4 mm × 5.5 mm, TA = 34s	8	For renal imaging
Umutlu et al[25], 2011	Prospective study	Siemens Terra; custom-built body Tx/Rx RF coil; T2w BSSFP, resolution 1.3 mm × 1.6 mm × 4.0 mm; T2w TSE; I/P and O/PGRE; T1w 2D FLASH, resolution 0.8 mm × 0.8 mm × 2.0 mm	10	To assess the feasibility of dynamic CE renal imaging
Umutlu et al[26], 2012	Prospective study	Siemens Terra; custom-built Tx/Rx RF body array coil; Coronal Fat-Saturated 2D FLASH , TA = 31s; Coronal Fat-Saturated 3D FLASH TA = 27s; Axial Fat-Saturated 2D TOF MRA TA = 33s	12	To investigate the feasibility of 7T nonenhanced high-field MRA of the renal vasculature and to evaluate the diagnostic potential of various non-enhanced T1-weighted spoiled gradient-echo sequences
Laader et al[29], 2018	Prospective study	Siemens Terra; custom-built eight-channel Tx/Rx RF body coil; axial 2D T1w TOF MRA TA = 33s; Coronal fat-saturated 3D low-dose CE T1w FLASH VIBE, TA = 27s	10	To evaluate the performance of time-of-flight MRA versus low-dose CE renal MRA at 7T in order to reduce and/or completely omit contrast agent use for renal MRA at 7T
Umutlu et al[27], 2013	Prospective study	Siemens Terra; custom-built Tx/Rx RF coil; coronal T1w3D FLASH sequence	8	To assess the feasibility of first-pass CE renal MRA at 7T

TR: Relaxation time; TE: Echo time; TA: Acquisition time; RF: Radiofrequency; T1w: T1 relaxation-weighting; T2w: T2 relaxation-weighting; TOF: Time-of-flight; MRA: Magnetic resonance angiography; CSI: Chemical shift imaging; MRSI: Magnetic resonance spectroscopic imaging; MSE: Multiple spin echo; MRF: Magnetic resonance fingerprinting; MP2RAGE: Magnetization-prepared 2 rapid acquisition gradient echo; MRCP: Magnetic resonance cholangiopancreatography; UTE: Ultrashort echo time; CE: Contrast-enhanced; FLASH: Fast low angle shot magnetic resonance imaging; FSE: Fast spin echo; TSE: Turbo spin echo; DWI: Diffusion weighted imaging; EPI: Echo planar imaging; HASTE: Half fourier single-shot turbo spin-echo; SSFP: Steady-state free precession MRI; N/A: Not applicable.