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Sibbach BM, Karim HT, Lo D, Kasibhatla N, Santini T, Weber JC, Ibrahim TS, Banihashemi L. Manual segmentation of the paraventricular nucleus of the hypothalamus and the dorsal and ventral bed nucleus of stria terminalis using multimodal 7 Tesla structural MRI: probabilistic atlases for a stress-control triad. Brain Struct Funct 2024; 229:273-283. [PMID: 37812278 PMCID: PMC10917873 DOI: 10.1007/s00429-023-02713-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 09/18/2023] [Indexed: 10/10/2023]
Abstract
The paraventricular nucleus of the hypothalamus (PVN) is uniquely capable of proximal control over autonomic and neuroendocrine stress responses, and the bed nucleus of the stria terminalis (BNST) directly modulates PVN function, as well as playing an important role in stress control itself. The dorsal BNST (dBNST) is predominantly preautonomic, while the ventral BNST (vBNST) is predominantly viscerosensory, receiving dense noradrenergic signaling. Distinguishing the dBNST and vBNST, along with the PVN, may facilitate our understanding of dynamic interactions among these regions. T1-weighted MPRAGE and high resolution gradient echo (GRE) modalities were acquired at 7T. GRE was coregistered to MPRAGE and segmentations were performed in MRIcroGL based on their Atlas of the Human Brain depictions. The dBNST, vBNST and PVN were manually segmented in 25 participants; 10 images were rated by 2 raters. These segmentations were normalized and probabilistic atlases for each region were generated in MNI space, now available as resources for future research. We found moderate-high inter-rater reliability [n = 10; Mean Dice (SD); PVN = 0.69 (0.04); dBNST = 0.77 (0.04); vBNST = 0.62 (0.04)]. Probabilistic atlases were reverse normalized into native space for six additional participants that were segmented but not included in the original 25. We also found moderate to moderate-high reliability between the probabilistic atlases and manual segmentations [n = 6; Mean Dice (SD); PVN = 0.55 (0.12); dBNST = 0.60 (0.10); vBNST = 0.47 (0.12 SD)]. By isolating these hypothalamic and BNST subregions using ultra-high field MRI modalities, more specific delineations of these regions can facilitate greater understanding of mechanisms underlying stress-related function and psychopathology.
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Affiliation(s)
- Brandon M Sibbach
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Helmet T Karim
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Daniel Lo
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Nithya Kasibhatla
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Tales Santini
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Jessica C Weber
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Tamer S Ibrahim
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Layla Banihashemi
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15213, USA.
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Whiting ME, Mettenburg J, Novelli EM, Santini T, Martins T, Ibrahim TS, LeDuc PR, Cagan J. Inducing Vascular Grammars for Anomaly Classification in Brain Angiograms. JOURNAL OF ENGINEERING AND SCIENCE IN MEDICAL DIAGNOSTICS AND THERAPY 2022; 5:021002. [PMID: 35833206 PMCID: PMC8932082 DOI: 10.1115/1.4053424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 12/23/2021] [Indexed: 11/08/2022]
Abstract
Abstract
As machine learning is used to make strides in medical diagnostics, few methods provide heuristics from which human doctors can learn directly. This work introduces a method for leveraging human observable structures, such as macroscale vascular formations, for producing assessments of medical conditions with relatively few training cases, and uncovering patterns that are potential diagnostic aids. The approach draws on shape grammars, a rule-based technique, pioneered in design and architecture, and accelerated through a recursive subgraph mining algorithm. The distribution of rule instances in the data from which they are induced is then used as an intermediary representation enabling common classification and anomaly detection approaches to identify indicative rules with relatively small data sets. The method is applied to seven-tesla time-of-flight angiography MRI (n = 54) of human brain vasculature. The data were segmented and induced to generate representative grammar rules. Ensembles of rules were isolated to implicate vascular conditions reliably. This application demonstrates the power of automated structured intermediary representations for assessing nuanced biological form relationships, and the strength of shape grammars, in particular for identifying indicative patterns in complex vascular networks.
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Affiliation(s)
- Mark E. Whiting
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Joseph Mettenburg
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA 15213
| | - Enrico M. Novelli
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213
| | - Tales Santini
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260
| | - Tiago Martins
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260
| | - Tamer S. Ibrahim
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260
| | - Philip R. LeDuc
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Jonathan Cagan
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
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Bhosale AA, Ying LL, Zhang X. Design of a 13-Channel hybrid RF array with field rectification of dielectric material for foot/ankle imaging at 7T. PROCEEDINGS OF THE INTERNATIONAL SOCIETY FOR MAGNETIC RESONANCE IN MEDICINE ... SCIENTIFIC MEETING AND EXHIBITION. INTERNATIONAL SOCIETY FOR MAGNETIC RESONANCE IN MEDICINE. SCIENTIFIC MEETING AND EXHIBITION 2022; 30:4433. [PMID: 36071700 PMCID: PMC9444995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Affiliation(s)
| | - Leslie L Ying
- Biomedical Engineering, University at Buffalo, Buffalo, NY, United States
| | - Xiaoliang Zhang
- Biomedical Engineering, University at Buffalo, Buffalo, NY, United States
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Improved 7 Tesla transmit field homogeneity with reduced electromagnetic power deposition using coupled Tic Tac Toe antennas. Sci Rep 2021; 11:3370. [PMID: 33564013 PMCID: PMC7873125 DOI: 10.1038/s41598-020-79807-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 11/26/2020] [Indexed: 12/28/2022] Open
Abstract
Recently cleared by the FDA, 7 Tesla (7 T) MRI is a rapidly growing technology that can provide higher resolution and enhanced contrast in human MRI images. However, the increased operational frequency (~ 297 MHz) hinders its full potential since it causes inhomogeneities in the images and increases the power deposition in the tissues. This work describes the optimization of an innovative radiofrequency (RF) head coil coupled design, named Tic Tac Toe, currently used in large scale human MRI scanning at 7 T; to date, this device was used in more than 1,300 neuro 7 T MRI scans. Electromagnetic simulations of the coil were performed using the finite-difference time-domain method. Numerical optimizations were used to combine the calculated electromagnetic fields produced by these antennas, based on the superposition principle, resulting in homogeneous magnetic field distributions at low levels of power deposition in the tissues. The simulations were validated in-vivo using the Tic Tac Toe RF head coil system on a 7 T MRI scanner.
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Krishnamurthy N, Santini T, Wood S, Kim J, Zhao T, Aizenstein HJ, Ibrahim TS. Computational and experimental evaluation of the Tic-Tac-Toe RF coil for 7 Tesla MRI. PLoS One 2019; 14:e0209663. [PMID: 30629618 PMCID: PMC6328242 DOI: 10.1371/journal.pone.0209663] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 12/10/2018] [Indexed: 01/18/2023] Open
Abstract
A variety of 7 Tesla RF coil systems have been proposed to produce spin excitation (B1+ field) and MR image acquisition. Different groups have attempted to mitigate the challenges at high and ultra-high field MRI by proposing novel hardware and software solutions to obtain uniformly high spin excitation at acceptable RF absorption levels. In this study, we extensively compare the designs of two distributed-circuit based RF coils: the Tic-Tac-Toe (TTT) head coil and TEM head coil on multiple anatomically detailed head models and in-vivo. Bench measurements of s-parameters and experimental B1+ field distribution were obtained in volunteers and compared with numerical simulations. RF absorption, quantified by both average and peak SAR, and B1+ field intensity and homogeneity, calculated/measured in terms of maximum over minimum and coefficient of variation (CV) in the region of interest (ROI), are presented for both coils. A study of the RF consistency of both coils across multiple head models for different RF excitation strategies is also presented.
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Affiliation(s)
- Narayanan Krishnamurthy
- University of Pittsburgh, Department of Bioengineering, Pittsburgh, PA, United States of America
| | - Tales Santini
- University of Pittsburgh, Department of Bioengineering, Pittsburgh, PA, United States of America
| | - Sossena Wood
- University of Pittsburgh, Department of Bioengineering, Pittsburgh, PA, United States of America
| | - Junghwan Kim
- University of Pittsburgh, Department of Bioengineering, Pittsburgh, PA, United States of America
| | - Tiejun Zhao
- Siemens Medical Solutions, New York, NY, United States of America
| | - Howard J. Aizenstein
- University of Pittsburgh, Department of Bioengineering, Pittsburgh, PA, United States of America
- University of Pittsburgh, Department of Psychiatry, Pittsburgh, PA, United States of America
| | - Tamer S. Ibrahim
- University of Pittsburgh, Department of Bioengineering, Pittsburgh, PA, United States of America
- University of Pittsburgh, Department of Psychiatry, Pittsburgh, PA, United States of America
- University of Pittsburgh, Department of Radiology, Pittsburgh, PA, United States of America
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Santini T, Zhao Y, Wood S, Krishnamurthy N, Kim J, Farhat N, Alkhateeb S, Martins T, Koo M, Zhao T, Aizenstein HJ, Ibrahim TS. In-vivo and numerical analysis of the eigenmodes produced by a multi-level Tic-Tac-Toe head transmit array for 7 Tesla MRI. PLoS One 2018; 13:e0206127. [PMID: 30481187 PMCID: PMC6258503 DOI: 10.1371/journal.pone.0206127] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 10/08/2018] [Indexed: 11/18/2022] Open
Abstract
Radio-frequency (RF) field inhomogeneities and higher levels of specific absorption rate (SAR) still present great challenges in ultrahigh-field (UHF) MRI. In this study, an in-depth analysis of the eigenmodes of a 20-channel transmit Tic-Tac-Toe (TTT) RF array for 7T neuro MRI is presented. The eigenmodes were calculated for five different Z levels (along the static magnetic field direction) of the coil. Four eigenmodes were obtained for each Z level (composed of 4 excitation ports), and they were named based on the characteristics of their field distributions: quadrature, opposite-phase, anti-quadrature, and zero-phase. Corresponding finite-difference time-domain (FDTD) simulations were performed and experimental B1+ field maps were acquired using a homogeneous spherical phantom and human head (in-vivo). The quadrature mode is the most efficient and it excites the central brain regions; the opposite-phase mode excites the brain peripheral regions; anti-quadrature mode excites the head periphery; and the zero-phase mode excites cerebellum and temporal lobes. Using this RF array, up to five eigenmodes (from five different Z levels) can be simultaneously excited. The superposition of these modes has the potential to produce homogeneous excitation with full brain coverage and low levels of SAR at 7T MRI.
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Affiliation(s)
- Tales Santini
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Yujuan Zhao
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Sossena Wood
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Narayanan Krishnamurthy
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Junghwan Kim
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Nadim Farhat
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Salem Alkhateeb
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Tiago Martins
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Minseok Koo
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Tiejun Zhao
- Siemens Medical Solutions, Pittsburgh, PA, United States of America
| | - Howard J. Aizenstein
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Psychiatry, University of Pittsburgh Medical Center, Pittsburgh, PA, United States of America
| | - Tamer S. Ibrahim
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Psychiatry, University of Pittsburgh Medical Center, Pittsburgh, PA, United States of America
- * E-mail:
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