OBJECTIVES: To compare ultra-high field, high-resolution bilateral magnetic resonance imaging (MRI) of the hips at 7 Tesla (T) with 3 T MRI in patients with avascular necrosis (AVN) of the femoral head by subjective image evaluations, contrast measurements, and evaluation of the appearance of imaging abnormalities. MATERIALS AND METHODS: Thirteen subjects with avascular necrosis treated using advanced core decompression underwent MRI at both 7 T and 3 T. Sequence parameters as well as resolution were kept identical for both field strengths. All MR images (MEDIC, DESS, PD/T2w TSE, T1w TSE, and STIR) were evaluated by two radiologists with regard to subjective image quality, soft tissue contrasts, B1 homogeneity (four-point scale, higher values indicating better image quality) and depiction of imaging abnormalities of the femoral heads (three-point scale, higher values indicating the superiority of 7 T). Contrast ratios of soft tissues were calculated and compared with subjective data. RESULTS: 7-T imaging of the femoral joints, as well as 3-T imaging, achieved "good" to "very good" quality in all sequences. 7 T showed significantly higher soft tissue contrasts for T2w and MEDIC compared with 3 T (cartilage/fluid: 2.9 vs 2.2 and 3.6 vs 2.6), better detailed resolution for cartilage defects (PDw, T2w, T1w, MEDIC, DESS > 2.5) and better visibility of joint effusions (MEDIC 2.6; PDw/T2w 2.4; DESS 2.2). Image homogeneity compared with 3 T (3.9-4.0 for all sequences) was degraded, especially in TSE sequences at 7 T through signal variations (7 T: 2.1-2.9); to a lesser extent also GRE sequences (7 T: 2.9-3.5). Imaging findings related to untreated or treated AVN were better delineated at 3 T (≤1.8), while joint effusions (2.2-2.6) and cartilage defects (2.5-3.0) were better visualized at 7 T. STIR performed much more poorly at 7 T, generating large contrast variations (1.5). CONCLUSIONS: 7-T hip MRI showed comparable results in hip joint imaging compared with 3 T with slight advantages in contrast detail (cartilage defects) and fluid detection at 7 T when accepting image degradation medially.
OBJECTIVES: To compare ultra-high field, high-resolution bilateral magnetic resonance imaging (MRI) of the hips at 7 Tesla (T) with 3 T MRI in patients with avascular necrosis (AVN) of the femoral head by subjective image evaluations, contrast measurements, and evaluation of the appearance of imaging abnormalities. MATERIALS AND METHODS: Thirteen subjects with avascular necrosis treated using advanced core decompression underwent MRI at both 7 T and 3 T. Sequence parameters as well as resolution were kept identical for both field strengths. All MR images (MEDIC, DESS, PD/T2w TSE, T1w TSE, and STIR) were evaluated by two radiologists with regard to subjective image quality, soft tissue contrasts, B1 homogeneity (four-point scale, higher values indicating better image quality) and depiction of imaging abnormalities of the femoral heads (three-point scale, higher values indicating the superiority of 7 T). Contrast ratios of soft tissues were calculated and compared with subjective data. RESULTS: 7-T imaging of the femoral joints, as well as 3-T imaging, achieved "good" to "very good" quality in all sequences. 7 T showed significantly higher soft tissue contrasts for T2w and MEDIC compared with 3 T (cartilage/fluid: 2.9 vs 2.2 and 3.6 vs 2.6), better detailed resolution for cartilage defects (PDw, T2w, T1w, MEDIC, DESS > 2.5) and better visibility of joint effusions (MEDIC 2.6; PDw/T2w 2.4; DESS 2.2). Image homogeneity compared with 3 T (3.9-4.0 for all sequences) was degraded, especially in TSE sequences at 7 T through signal variations (7 T: 2.1-2.9); to a lesser extent also GRE sequences (7 T: 2.9-3.5). Imaging findings related to untreated or treated AVN were better delineated at 3 T (≤1.8), while joint effusions (2.2-2.6) and cartilage defects (2.5-3.0) were better visualized at 7 T. STIR performed much more poorly at 7 T, generating large contrast variations (1.5). CONCLUSIONS: 7-T hip MRI showed comparable results in hip joint imaging compared with 3 T with slight advantages in contrast detail (cartilage defects) and fluid detection at 7 T when accepting image degradation medially.
Authors: Siegfried Trattnig; Stefan Zbýň; Benjamin Schmitt; Klaus Friedrich; Vladimir Juras; Pavol Szomolanyi; Wolfgang Bogner Journal: Eur Radiol Date: 2012-06-12 Impact factor: 5.315
Authors: Marnix C Maas; Eline K Vos; Miriam W Lagemaat; Andreas K Bitz; Stephan Orzada; Thiele Kobus; Oliver Kraff; Stefan Maderwald; Mark E Ladd; Tom W J Scheenen Journal: Magn Reson Med Date: 2013-06-24 Impact factor: 4.668
Authors: Cem Murat Deniz; Ryan Brown; Riccardo Lattanzi; Leeor Alon; Daniel K Sodickson; Yudong Zhu Journal: Magn Reson Med Date: 2012-06-19 Impact factor: 4.668
Authors: Andrea Lazik; Jens M Theysohn; Christina Geis; Sören Johst; Mark E Ladd; Harald H Quick; Oliver Kraff Journal: Eur Radiol Date: 2015-08-28 Impact factor: 5.315
Authors: Andrea Lazik-Palm; Oliver Kraff; Christina Geis; Sören Johst; Juliane Goebel; Mark E Ladd; Harald H Quick; Jens M Theysohn Journal: Eur Radiol Date: 2016-02-12 Impact factor: 5.315
Authors: Oliver Kraff; Andrea Lazik-Palm; Rahel Heule; Jens M Theysohn; Oliver Bieri; Harald H Quick Journal: MAGMA Date: 2016-04-25 Impact factor: 2.310
Authors: Emily S Mills; Jacob A Becerra; Katie Yensen; Ioanna K Bolia; Edward C Shontz; Kareem J Kebaish; Andrew Dobitsch; Laith K Hasan; Aryan Haratian; Charlton D Ong; Jordan Gross; Frank A Petrigliano; Alexander E Weber Journal: Orthop Res Rev Date: 2022-09-14