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Malis V, Bae WC, Yamamoto A, Kassai Y, McDonald MA, Miyazaki M. Aliphatic and Olefinic Fat Suppression in the Orbit Using Polarity-altered Spectral and Spatial Selective Acquisition (PASTA) with Opposed Phase. Magn Reson Med Sci 2024; 23:193-203. [PMID: 36948628 PMCID: PMC11024719 DOI: 10.2463/mrms.mp.2022-0073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 02/12/2023] [Indexed: 03/24/2023] Open
Abstract
PURPOSE Fatty acid composition of the orbit makes it challenging to achieve complete fat suppression during orbit MR imaging. Implementation of a fat suppression technique capable of suppressing signals from saturated (aliphatic) and unsaturated (olefinic or protons at double-bonded carbon sites) fat would improve the visualization of an optical nerve. Furthermore, the ability to semi-quantify the fractions of aliphatic and olefinic fat may potentially provide valuable information in assessing orbit pathology. METHODS A phantom study was conducted on various oil samples on a clinical 3 Tesla scanner. The imaging protocol included three 2D fast spin echo (FSE) sequences: in-phase, polarity-altered spectral and spatial selective acquisition (PASTA), and a combination of PASTA with opposed phase in olefinic and aliphatic chemical shift. The results were validated against high-resolution 11.7T NMR and compared with images acquired with spectral attenuated inversion recovery (SPAIR) and chemical shift selective (CHESS) fat suppression techniques. In-vivo data were acquired on eight healthy subjects and were compared with the prior histological studies. RESULTS PASTA with opposed phase achieved complete suppression of fat signals in the orbits and provided images of well-delineated optical nerves and muscles in all subjects. The olefinic fat fraction in the olive, walnut, and fish oil phantoms at 3T was found to be 5.0%, 11.2%, and 12.8%, respectively, whereas 11.7T NMR provides the following olefinic fat fractions: 6.0% for olive, 11.5% for walnut, and 12.6% for fish oils. For the in-vivo study, on average, olefinic fat accounted for 9.9% ± 3.8% of total fat while the aliphatic fat fraction was 90.1% ± 3.8%, in the normal orbits. CONCLUSION We have introduced a new fat suppression technique using PASTA with opposed phase and applied it to human orbits. The purposed method achieves an excellent orbital fat suppression and the quantification of aliphatic and olefinic fat signals.
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Affiliation(s)
- Vadim Malis
- Department of Radiology, University of California San Diego, La Jolla, CA, USA
| | - Won C. Bae
- Department of Radiology, University of California San Diego, La Jolla, CA, USA
- Department of Radiology, VA San Diego Healthcare System, San Diego, CA, USA
| | - Asako Yamamoto
- Department of Radiology, Teikyo University, Tokyo, Japan
| | - Yoshimori Kassai
- CT-MR Solution Planning Department, Canon Medical Systems Corp., Otawara, Tochigi, Japan
| | - Marin A McDonald
- Department of Radiology, University of California San Diego, La Jolla, CA, USA
| | - Mitsue Miyazaki
- Department of Radiology, University of California San Diego, La Jolla, CA, USA
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Pseudo-T2 mapping for normalization of T2-weighted prostate MRI. MAGMA (NEW YORK, N.Y.) 2022; 35:573-585. [PMID: 35150363 PMCID: PMC9363383 DOI: 10.1007/s10334-022-01003-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/22/2021] [Accepted: 01/23/2022] [Indexed: 01/04/2023]
Abstract
Objective Signal intensity normalization is necessary to reduce heterogeneity in T2-weighted (T2W) magnetic resonance imaging (MRI) for quantitative analysis of multicenter data. AutoRef is an automated dual-reference tissue normalization method that normalizes transversal prostate T2W MRI by creating a pseudo-T2 map. The aim of this study was to evaluate the accuracy of pseudo-T2s and multicenter standardization performance for AutoRef with three pairs of reference tissues: fat/muscle (AutoRefF), femoral head/muscle (AutoRefFH) and pelvic bone/muscle (AutoRefPB). Materials and methods T2s measured by multi-echo spin echo (MESE) were compared to AutoRef pseudo-T2s in the whole prostate (WP) and zones (PZ and TZ/CZ/AFS) for seven asymptomatic volunteers with a paired Wilcoxon signed-rank test. AutoRef normalization was assessed on T2W images from a multicenter evaluation set of 1186 prostate cancer patients. Performance was measured by inter-patient histogram intersections of voxel intensities in the WP before and after normalization in a selected subset of 80 cases. Results AutoRefFH pseudo-T2s best approached MESE T2s in the volunteer study, with no significant difference shown (WP: p = 0.30, TZ/CZ/AFS: p = 0.22, PZ: p = 0.69). All three AutoRef versions increased inter-patient histogram intersections in the multicenter dataset, with median histogram intersections of 0.505 (original data), 0.738 (AutoRefFH), 0.739 (AutoRefF) and 0.726 (AutoRefPB). Discussion All AutoRef versions reduced variation in the multicenter data. AutoRefFH pseudo-T2s were closest to experimentally measured T2s. Supplementary Information The online version contains supplementary material available at 10.1007/s10334-022-01003-9.
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Willaert R, Degrieck B, Orhan K, Deferm J, Politis C, Shaheen E, Jacobs R. Semi-automatic magnetic resonance imaging based orbital fat volumetry: reliability and correlation with computed tomography. Int J Oral Maxillofac Surg 2020; 50:416-422. [PMID: 32814653 DOI: 10.1016/j.ijom.2020.07.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 04/19/2020] [Accepted: 07/23/2020] [Indexed: 12/22/2022]
Abstract
Post-processing analysis can provide valuable information for diagnosis and planning of orbital disorders. This cross-sectional study aims to evaluate the reliability of semi-automatic, orbital fat volumetry using magnetic resonance imaging (MRI). Two observers assessed the orbital fat volume using a standard MRI protocol (3T, T1w sequence) in 12 orbits diagnosed with Graves' orbitopathy (GO) and 10 healthy control orbits. MRI and computed tomography (CT) based analysis were compared. Intra-observer variability was good (intraclass correlation coefficient (ICC) 0.88; 95% confidence interval (CI) [0.70, 0.95]) and interobserver agreement was moderate (ICC 0.55; 95% CI [-0.09, 0.81]), which corresponds to a mean percentage difference of 1.3% and 17.9% of the total orbital fat volume. Mean differences between MRI and CT measurements were, respectively, 1.1 cm3 (P= 0.064, 95% CI [-0.20, 2.43]) and 1.4 cm3 (P=0.016, 95% CI [0.21, 2.56]) for the control and the GO group. MRI volumetry was strongly correlated with CT (Pearson's r= 0.7, P<0.001). We conclude that orbital fat volumetry is feasible with a semi-automatic segmentation procedure and standard MRI protocol. Correlation with CT volumetry is good, but considerable bias may derive from observer variability and these errors should be taken into account for the purpose of volumetric analysis. Better definition of error sources may increase measurement accuracy.
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Affiliation(s)
- R Willaert
- Department of Head and Neck Surgery, Ghent University Hospital, Ghent, Belgium; Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium.
| | - B Degrieck
- Department of Radiology, Ghent University Hospital, Ghent, Belgium
| | - K Orhan
- OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU Leuven, Leuven, Belgium; Ankara University, Faculty of Dentistry, Department of DentoMaxillofacial Radiology, Ankara, Turkey
| | - J Deferm
- Department of Oral and Maxillofacial Surgery, Radboud UMC, Nijmegen, The Netherlands
| | - C Politis
- Department of Oral and Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium; OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - E Shaheen
- OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - R Jacobs
- OMFS IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, KU Leuven, Leuven, Belgium; Department of Dental Medicine, Karolinska Institutet, Stockholm, Sweden
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Bontzos G, Mazonakis M, Papadaki E, Maris TG, Blazaki S, Drakonaki EE, Detorakis ET. Orbital volume measurements from magnetic resonance images using the techniques of manual planimetry and stereology. Natl J Maxillofac Surg 2020; 11:20-27. [PMID: 33041572 PMCID: PMC7518488 DOI: 10.4103/njms.njms_9_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 05/08/2020] [Accepted: 05/15/2020] [Indexed: 11/23/2022] Open
Abstract
Introduction: Current volume measurement techniques, for the orbit, are time-consuming and involve complex assessments, which prevents their routine clinical use. In this study, we evaluate the applicability and efficacy of stereology and planimetry in orbital volume measurements using magnetic resonance imaging (MRI). Materials and Methods: Prospective imaging study using MRI. Sheep craniums and human subjects were evaluated. Water-filling measurements were performed in animal skulls, as the standard validation technique. Planimetry and stereology techniques were used in each dataset. Intraobserver and interobserver reliability testing were applied. Results: In stereology customization, 1/6 systematic sampling scheme was determined as optimal with acceptable coefficient of error (3.09%) and low measurement time (1.2 min). In sheep craniums, the mean volume measured by water displacement, planimetry, and stereology was 17.81 ± 0.59 cm3, 18.53 ± 0.24 cm3, and 19.19 ± 0.17 cm3, respectively. Planimetric and stereological methods were highly correlated (r = 0.94; P ≈ 0.001). The mean difference of the orbital volume using planimetry and stereology was 0.316 ± 0.168 cm3. In human subjects, using stereology, the mean orbital volume was found to be 19.62 ± 0.2 cm3 with a CE of 3.91 ± 0.15%. Conclusions: The optimized stereological method was found superior to manual planimetry in terms of user effort and time spent. Stereology sampling of 1/6 was successfully applied in human subjects and showed strong correlation with manual planimetry. However, optimized stereological method tended to overestimate the orbital volume by about 1 cc, a considerable limitation to be taken in clinical practice.
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Affiliation(s)
- Georgios Bontzos
- Department of Ophthalmology, University Hospital of Heraklion, Heraklion, Crete, Greece
| | - Michael Mazonakis
- Department of Medical Physics, University of Crete, Heraklion, Greece
| | - Efrosini Papadaki
- Department of Radiology, University Hospital of Heraklion, Heraklion, Greece
| | - Thomas G Maris
- Department of Medical Physics, University of Crete, Heraklion, Greece
| | - Styliani Blazaki
- Department of Ophthalmology, University Hospital of Heraklion, Heraklion, Crete, Greece
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Chen Q, Ma R, Gan L, Ren H, Yuan Y. Value of ultrasound biomicroscopy in assessment of small masses at medial canthal region. Graefes Arch Clin Exp Ophthalmol 2019; 257:827-834. [PMID: 30671657 DOI: 10.1007/s00417-019-04252-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/06/2019] [Accepted: 01/11/2019] [Indexed: 11/28/2022] Open
Abstract
PURPOSE Conventional imaging techniques are not sensitive enough to reveal detailed structures of lacrimal drainage system (LDS) and its surrounding tissue (ST). Our study aimed to explore utility of ultrasound biomicroscopy (UBM) in assessment of small masses at the medial canthal region and compare performance of UBM with conventional imaging techniques. METHODS We prospectively recruited cases with small mass (long axis < 1 cm) at the medial canthal region (upper LDS-located area) from June 2017 to October 2018. UBM ± color Doppler flow imaging (CDFI) and conventional imaging techniques (computed tomography, magnetic resonance imaging, and dacryocystography) were conducted by four independent practitioners. Results were analyzed against gold standards with Cohen's kappa test in three aspects including LDS patency, mass location, and presumptive diagnosis. Corresponding gold standards were syringe and dacryocystography, intraoperative findings, and pathological/empirical diagnosis. RESULTS Seventy-two cases were recruited, including 20 cases of LDS lesions and 52 cases of ST lesions. Female (odds ratio 7.14) and age ≥ 37 (odds ratio 9.80) were risk factors for LDS lesion, and age range of 15-25 (odds ratio 9.17) was a risk factor for inflammatory ST lesion. In terms of LDS patency, UBM results were reliable for the detection of pre-saccal obstruction (kappa = 0.920), but were not reliable for intra-saccal and post-saccal obstruction (kappa = 0.106). In terms of mass location, the UBM (kappa = 0.766) performed better than conventional techniques (except for dacryocystography) to sort out ST lesions, with sensitivity of 93.8% and specificity of 83.3%. In terms of diagnosis, the UBM (kappa = 0.882) outweighed conventional techniques (except for magnetic resonance imaging) to distinguish cysts from nodules, with sensitivity of 93.8% and specificity of 94.4%. Notably, the UBM + CDFI achieved better performance than the UBM when screen out inflammatory lesions (kappa = 0.926 vs kappa = 0.689) and LDS-adjacent lesions (kappa = 0.815 vs kappa = 0.673), resulting in sensitivity of 91.7% and specificity of 100% for both testing items. If deep lesions (at the lacrimal sac-harbored area) were excluded, UBM reliability to detect inflammatory lesions (kappa = 0.915) and LDS-adjacent lesions (kappa = 0.770) improved, achieving sensitivity of 90.0% and 88.9%, and specificity of 100.0% and 92.7%, respectively. CONCLUSIONS The UBM is a valuable tool to assess superficial masses at the medial canthal region regarding pre-saccal obstruction, mass location, and presumptive diagnosis. TRIAL REGISTRATION This work was registered on Chinese Clinical Trial Registry website with registration number ChiCTR1800018956 .
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Affiliation(s)
- Qian Chen
- Department of Ophthalmology, Fudan Eye and ENT Hospital, 83 Fen Yang Road, Xuhui District, Shanghai, 200031, China
| | - Ruiqi Ma
- Department of Ophthalmology, Fudan Eye and ENT Hospital, 83 Fen Yang Road, Xuhui District, Shanghai, 200031, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Lu Gan
- Department of Ophthalmology, Fudan Eye and ENT Hospital, 83 Fen Yang Road, Xuhui District, Shanghai, 200031, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Hui Ren
- Department of Ophthalmology, Fudan Eye and ENT Hospital, 83 Fen Yang Road, Xuhui District, Shanghai, 200031, China
| | - Yifei Yuan
- Department of Ophthalmology, Fudan Eye and ENT Hospital, 83 Fen Yang Road, Xuhui District, Shanghai, 200031, China.
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