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Bougia CΚ, Astrakas L, Pappa O, Maliakas V, Sofikitis N, Argyropoulou MI, Tsili AC. Diffusion tensor imaging and fiber tractography of the normal epididymis. Abdom Radiol (NY) 2024; 49:2932-2941. [PMID: 38836882 DOI: 10.1007/s00261-024-04372-y] [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: 03/23/2024] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 06/06/2024]
Abstract
PURPOSE To evaluate the feasibility of diffusion tensor imaging (DTI) and fiber tractography (FT) of the normal epididymis and to determine normative apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values. METHODS Twenty-eight healthy volunteers underwent MRI of the scrotum, including DTI on a 3.0 T system. For each anatomic part of the epididymis (head, body and tail) free-hand regions of interest were drawn and the mean ADC and FA were measured by two radiologists in consensus. Parametric statistical tests were used to determine intersubject differences in ADC and FA between the anatomic parts of each normal epididymis and between bilateral epididymides. Fiber tracts of the epididymis were reconstructed using the MR Diffusion tool. RESULTS The mean ADC and FA of the normal epididymis was 1.31 × 10-3 mm2/s and 0.20, respectively. No differences in ADC (p = 0.736) and FA (p = 0.628) between the anatomic parts of each normal epididymis were found. Differences (p = 0.020) were observed in FA of the body between the right and the left epididymis. FT showed the fiber tracts of the normal epididymis. Main study's limitations include the following: small number of participants with narrow age range, absence of histologic confirmation and lack of quantitative assessment of the FT reconstructions. CONCLUSION DTI and FT of the normal epididymis is feasible and allow the noninvasive assessment of the structural and geometric organization of the organ.
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Affiliation(s)
- Christina Κ Bougia
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, 45110, Ioannina, Greece
| | - Loukas Astrakas
- Department of Medical Physics, School of Health Sciences, Faculty of Medicine, University of Ioannina, 45110, Ioannina, Greece
| | - Ourania Pappa
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, 45110, Ioannina, Greece
| | - Vasileios Maliakas
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, 45110, Ioannina, Greece
- Department of Clinical Radiology, University Hospital of Ioannina, St. Niarchos, 45500, Ioannina, Greece
| | - Nikolaos Sofikitis
- Department of Urology, School of Health Sciences, Faculty of Medicine, University of Ioannina, 45110, Ioannina, Greece
| | - Maria I Argyropoulou
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, 45110, Ioannina, Greece
| | - Athina C Tsili
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, 45110, Ioannina, Greece.
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Pappa O, Astrakas L, Anagnostou N, Bougia CΚ, Maliakas V, Sofikitis N, Argyropoulou MI, Tsili AC. 3.0 T diffusion tensor imaging and fiber tractography of the testes in nonobstructive azoospermia. Abdom Radiol (NY) 2024:10.1007/s00261-024-04457-8. [PMID: 38940912 DOI: 10.1007/s00261-024-04457-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Revised: 06/15/2024] [Accepted: 06/17/2024] [Indexed: 06/29/2024]
Abstract
PURPOSE To assess the role of 3.0 T Diffusion Tensor Imaging (DTI) and Fiber Tractography (FT) of the testes in the work-up of nonobstructive azoospermia (NOA). METHODS This prospective study included consecutive NOA men and controls. A 3.0 T scrotal MRI was performed, including DTI. The testicular apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were calculated. FT reconstructions were created. The Kruskal-Wallis test, followed by pairwise comparisons, assessed differences in testicular ADC and FA between NOA histologic phenotypes (group 1: hypospermatogenesis; group 2: maturation arrest; and group 3: Sertoli cell-only syndrome) and normal testes. The Mann-Whitney-U test compared ADC and FA between NOA testes with positive and negative sperm retrieval. Visual assessment of the testicular fiber tracts was performed. Fiber tracts fewer in number, of reduced thickness, disrupted and/or disorganized were considered "abnormal". Chi-square tests and binary logistic regression analysis assessed variations in testicular fiber tracts morphology. RESULTS Twenty-nine NOA men (mean age: 39 ± 5.93 years) and 20 controls (mean age: 26 ± 5.83 years) were included for analysis. Higher ADC (p < 0.001) and FA (p < 0.001) was observed in NOA testes compared to controls. Differences in FA were found between groups 1 and 3 (0.07 vs 0.10, p = 0.26) and groups 2 and 3 (0.07 vs 0.10, p = 0.03), but not between groups 1 and 2 (p = 0.66). An increase in FA was observed in NOA testes with Sertoli cell-only syndrome compared to hypospermatogenesis and maturation arrest. FA was higher in NOA testes with negative results for the presence of sperm compared to those with positive results (0.09 vs 0.07, p = 0.006). FT showed "abnormal" fiber tracts in NOA testes (p < 0.001). CONCLUSION 3.0 T DTI and FT provide an insight into deranged spermatogenesis in NOA testes.
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Affiliation(s)
- Ourania Pappa
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, University Campus, 45110, Ioannina, Greece
| | - Loukas Astrakas
- Department of Medical Physics, School of Health Sciences, Faculty of Medicine, University of Ioannina, 45110, Ioannina, Greece
| | - Nikoletta Anagnostou
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, University Campus, 45110, Ioannina, Greece
| | - Christina Κ Bougia
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, University Campus, 45110, Ioannina, Greece
| | - Vasileios Maliakas
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, University Campus, 45110, Ioannina, Greece
- Department of Clinical Radiology, University Hospital of Ioannina, St. Niarchos 45500, Ioannina, Greece
| | - Nikolaos Sofikitis
- Department of Urology, School of Health Sciences, Faculty of Medicine, University of Ioannina, 45110, Ioannina, Greece
| | - Maria I Argyropoulou
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, University Campus, 45110, Ioannina, Greece
| | - Athina C Tsili
- Department of Clinical Radiology, School of Health Sciences, Faculty of Medicine, University of Ioannina, University Campus, 45110, Ioannina, Greece.
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Vinding MS, Aigner CS, Schmitter S, Lund TE. DeepControl: 2DRF pulses facilitating B 1 + inhomogeneity and B 0 off-resonance compensation in vivo at 7 T. Magn Reson Med 2021; 85:3308-3317. [PMID: 33480029 DOI: 10.1002/mrm.28667] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 01/26/2023]
Abstract
PURPOSE Rapid 2DRF pulse design with subject-specific B 1 + inhomogeneity and B0 off-resonance compensation at 7 T predicted from convolutional neural networks is presented. METHODS The convolution neural network was trained on half a million single-channel transmit 2DRF pulses optimized with an optimal control method using artificial 2D targets, B 1 + and B0 maps. Predicted pulses were tested in a phantom and in vivo at 7 T with measured B 1 + and B0 maps from a high-resolution gradient echo sequence. RESULTS Pulse prediction by the trained convolutional neural network was done on the fly during the MR session in approximately 9 ms for multiple hand-drawn regions of interest and the measured B 1 + and B0 maps. Compensation of B 1 + inhomogeneity and B0 off-resonances has been confirmed in the phantom and in vivo experiments. The reconstructed image data agree well with the simulations using the acquired B 1 + and B0 maps, and the 2DRF pulse predicted by the convolutional neural networks is as good as the conventional RF pulse obtained by optimal control. CONCLUSION The proposed convolutional neural network-based 2DRF pulse design method predicts 2DRF pulses with an excellent excitation pattern and compensated B 1 + and B0 variations at 7 T. The rapid 2DRF pulse prediction (9 ms) enables subject-specific high-quality 2DRF pulses without the need to run lengthy optimizations.
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Affiliation(s)
- Mads Sloth Vinding
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus N, Denmark
| | | | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Germany.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA
| | - Torben Ellegaard Lund
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus N, Denmark
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Fang S, Bai HX, Fan X, Li S, Zhang Z, Jiang T, Wang Y. A Novel Sequence: ZOOMit-Blood Oxygen Level-Dependent for Motor-Cortex Localization. Neurosurgery 2020; 86:E124-E132. [PMID: 31642505 DOI: 10.1093/neuros/nyz441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 08/18/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Use of conventional blood oxygen level-dependent functional magnetic resonance imaging (conventional-BOLD-fMRI) presents challenges in accurately identifying the hand-motor cortex when a glioma involves the ipsilateral hand-knob. Zoomed imaging technique with parallel transmission (ZOOMit)-BOLD is a novel sequence allowing high spatial resolution with a relatively small field of view that may solve this problem. OBJECTIVE To compare the accuracy of ZOOMit-BOLD and conventional-BOLD in hand-motor cortex identification. METHODS A total of 20 patients with gliomas involving the sensorimotor cortex were recruited to identify the hand-motor cortex by both ZOOMit-BOLD and conventional-BOLD. Based on whether the entire or partial glioma directly invaded (was located within) the hand-knob or indirectly affected it by proximity, patients were placed into the involved or uninvolved groups, respectively. Direct cortical stimulation was applied intraoperatively to verify the location of the hand-motor cortex. Overlap indices were used to evaluate the accuracy of the hand-motor cortex identification. An overlap index equal to 0, indicating lack of overlap, was classified as inaccurate classification. RESULTS The accuracy of motor-cortex identification with ZOOMit-BOLD was 100% compared to only 65% with conventional-BOLD. The average overlap index yielded by ZOOMit-BOLD was higher than that of conventional-BOLD, regardless of whether gliomas directly invaded the hand-knob (P = .008) or not (P = .004). The overlap index in the involved group was significantly lower than that in the uninvolved group with both ZOOMit-BOLD (P = .002) and conventional-BOLD (P < .001). CONCLUSION ZOOMit-BOLD may potentially replace conventional-BOLD to identify the hand-motor cortex, particularly in cases in which gliomas directly invade the hand-knob.
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Affiliation(s)
- Shengyu Fang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Harrison X Bai
- Department of Diagnostic Imaging, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Providence, Rhode Island
| | - Xing Fan
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
| | - Shaowu Li
- Functional Neuroradiology Center, Beijing Neurosurgical Institute, Beijing, China
| | - Zhong Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Tao Jiang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Beijing Neurosurgical Institute, Capital Medical University, Beijing, China.,Beijing Institute for Brain Disorders Brain Tumor Center, Beijing, China
| | - Yinyan Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Beijing Neurosurgical Institute, Capital Medical University, Beijing, China
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Abstract
Magnetic resonance imaging (MRI) has been driven toward ultrahigh magnetic fields (UHF) in order to benefit from correspondingly higher signal-to-noise ratio and spectral resolution. Technological challenges associated with UHF, such as increased radiofrequency (RF) energy deposition and RF excitation inhomogeneity, limit realization of the full potential of these benefits. Parallel RF transmission (pTx) enables decreases in the inhomogeneity of RF excitations and in RF energy deposition by using multiple-transmit RF coils driven independently and operating simultaneously. pTx plays a fundamental role in UHF MRI by bringing the potential applications of UHF into reality. In this review article, we review the recent developments in pTx pulse design and RF safety in pTx. Simultaneous multislice imaging and inner volume imaging using pTx are reviewed with a focus on UHF applications. Emerging pTx design approaches using improved pTx design frameworks and calibrations are reviewed together with calibration-free approaches that remove the necessity of time-consuming calibrations necessary for successful pTx. Lastly, we focus on the safety of pTx that is improved by using intersubject variability analysis, proactively managing pTx and temperature-based pTx approaches.
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Affiliation(s)
- Cem M. Deniz
- Center for Advanced Imaging Innovation and Research (CAI2R) and Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY
- RF Test Labs, LLC, New York, NY
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Hedgire S, Kilcoyne A, Tonyushkin A, Mao Y, Uyeda JW, Gervais DA, Harisinghani MG. Effect of androgen deprivation and radiation therapy on MRI fiber tractography in prostate cancer: can we assess treatment response on imaging? Br J Radiol 2018; 92:20170170. [PMID: 30209952 DOI: 10.1259/bjr.20170170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To evaluate quantitative changes in Diffusion Tensor Magnetic Resonance Tractography in prostate cancer following androgen deprivation and radiation therapy. METHODS 22 patients with elevated PSA and biopsy proven prostate carcinoma who underwent MRI of the prostate at 1.5 T with an endorectal coil were included. Group A) was the study group (n = 11), participants who underwent androgen deprivation and/or radiation therapy and group B) were Gleason-matched control group (n = 11) participants who did not undergo such therapy. Diffusion weighted images were used to generate three-dimensional (3D) map of fiber tracts from DTI. 3D regions of interest (ROI) were drawn over the tumor and healthy prostatic parenchyma in both groups to record tract number and tract density. Tumor region and normal parenchymal tract densities within each group were compared. RESULTS Mean tract density in the tumor region and normal parenchyma was 2.3 and 3.3 in study group (tract numbers: 116.6 and 170.2 respectively) and 1.6 and 2.7 in the control group respectively (tract numbers: 252.5 and 346.3 respectively). The difference between these values was statistically significant for the control group (p = 0.0018) but not for the study group (p = 0.11). The difference between the tract numbers of tumor and normal parenchyma appears to narrow following therapy. CONCLUSION The study demonstrated utility in using tractography as a biomarker in prostate cancer patients post treatment. ADVANCES IN KNOWLEDGE Quantitative DTI fiber tractography is a promising imaging biomarker to quantitatively assess treatment response in the setting of post-androgen deprivation and radiation therapy for prostate cancer.
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Affiliation(s)
- Sandeep Hedgire
- Department of Radiology, Division of Abdominal Imaging, Massachusetts General Hospital, Boston, MA, USA
| | - Aoife Kilcoyne
- Department of Radiology, Division of Abdominal Imaging, Massachusetts General Hospital, Boston, MA, USA
| | - Alexey Tonyushkin
- Department of Radiology, Division of Abdominal Imaging, Massachusetts General Hospital, Boston, MA, USA.,Physics Department, University of Massachusetts Boston, Boston, MA, USA
| | - Yun Mao
- Department of Radiology, The first affiliated hospital of Chongqing Medical University, Chongqing, China
| | - Jennifer W Uyeda
- Department of Radiology, Brigham and Women's Hospital, Boston, MA, USA
| | - Debra A Gervais
- Department of Radiology, Division of Abdominal Imaging, Massachusetts General Hospital, Boston, MA, USA
| | - Mukesh G Harisinghani
- Department of Radiology, Division of Abdominal Imaging, Massachusetts General Hospital, Boston, MA, USA
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Jomoto W, Tanooka M, Wakayama T, Minamoto T, Suzuki T, Ishikura R, Yamamoto S, Kotoura N. Evaluation of local look diffusion tensor imaging for magnetic resonance tractography of the periprostatic neurovascular bundle. Radiol Phys Technol 2018; 11:353-359. [DOI: 10.1007/s12194-018-0470-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/29/2018] [Accepted: 07/31/2018] [Indexed: 11/30/2022]
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Wang YT, Li YC, Kong WF, Yin LL, Pu H. Diffusion tensor imaging beyond brains: Applications in abdominal and pelvic organs. World J Meta-Anal 2017; 5:71-79. [DOI: 10.13105/wjma.v5.i3.71] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 04/12/2017] [Accepted: 04/24/2017] [Indexed: 02/06/2023] Open
Abstract
Functional magnetic resonance imaging (MRI) provided critical functional information in addition to the anatomic profiles offered by conventional MRI, and has been enormously used in the initial diagnosis and followed evaluation of various diseases. Diffusion tensor imaging (DTI) is a newly developed and advanced technique that measures the diffusion properties including both diffusion motion and its direction in situ, and has been extensively applied in central nerve system with acknowledged success. Technical advances have enabled DTI in abdominal and pelvic organs. Its application is increasing, yet remains less understood. A systematic overview of clinical application of DTI in abdominal and pelvic organs such as liver, pancreas, kidneys, prostate, uterus, etc., is therefore presented. Exploration of techniques with less artifacts and more normative post-processing enabled generally satisfactory image quality and repeatability of measurement. DTI appears to be more valuable in the evaluation of diffused diseases of organs with highly directionally arranged structures, such as the assessment of function impairment of native and transplanted kidneys. However, the utility of DTI to diagnose focal lesions, such as liver mass, pancreatic and prostate tumor, remains limited. Besides, diffusion of different layers of the uterus and the fiber structure disruption can be depicted by DTI. Finally, a discussion of future directions of research is given. The underlying heterogeneous pathologic conditions of certain diseases need to be further differentiated, and it is suggested that DTI parameters might potentially depict certain pathologic characterization such as cell density. Nevertheless, DTI should be better integrated into the current multi-modality evaluation in clinical practice.
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