A time‐efficient acquisition protocol for multipurpose diffusion‐weighted microstructural imaging at 7 Tesla

Sepehrband, Farshid; O’Brien, Kieran; Barth, Markus

doi:10.1002/mrm.26608

Cited by 18 publications

(15 citation statements)

References 81 publications

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“…Notably, our previous study found that mouse sublayer 4 neurons had a high degree of interconnectivity along the transverse hippocampal axis and the fiber tract identified in the TDI fiber analysis suggests a similar connectivity pathway exists in humans. As the resolution of MRI imaging technology continues to improve and microstructural imaging becomes clinically feasible and quantitatively-specific [30][31][32] , we believe the data here provides an important foundation for an integrative approach to bridge the gap between MRI imaging and human tissue histology.…”

Section: Discussionmentioning

confidence: 82%

Homologous laminar organization of the mouse and human subiculum

Bienkowski

Sepehrband

Kurniawan

et al. 2019

Preprint

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The subiculum is the major output structure of the hippocampal formation and one of the brain regions most affected by Alzheimer's disease. Our previous work revealed a hidden laminar architecture within the mouse subiculum. However, the rotation of the hippocampal longitudinal axis across species makes it unclear how the laminar organization is represented in human subiculum. Using in situ hybridization data from the Allen Human Brain Atlas, we demonstrate that the human subiculum also contains complementary laminar gene expression patterns similar to the mouse. In addition, we provide evidence that the molecular domain boundaries in human subiculum correspond to microstructural differences observed in high resolution MRI and fiber density imaging. Finally, we show both similarities and differences in the gene expression profile of subiculum pyramidal cells within homologous lamina.Overall, we present a new 3D model of the anatomical organization of human subiculum and its evolution from the mouse.

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Section: Discussionmentioning

confidence: 82%

Homologous laminar organization of the mouse and human subiculum

Bienkowski

Sepehrband

Kurniawan

et al. 2019

Preprint

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“…These procedures are time consuming. For many clinical cases and studies, the scan time is limited because the patients are pediatric or elderly, have severe anxiety or other psychiatric conditions, or have difficulty holding their breath . Hence, longer SE or STE scans are not suitable, whereas ISTE is a viable way to increase the SNR in diffusion MRI in these conditions.…”

Section: Discussionmentioning

confidence: 96%

“…For many clinical cases and studies, the scan time is limited because the patients are pediatric or elderly, have severe anxiety or other psychiatric conditions, or have difficulty holding their breath. 15,29 Hence, longer SE or STE scans are not suitable, whereas ISTE is a viable way to increase the SNR in diffusion MRI in these conditions. Through improved SNRs, ISTE can facilitate clinical diagnosis and may potentially be applied to diffusion MRI radiomics to more accurately diagnose tumors.…”

Section: Discussionmentioning

confidence: 99%

Improved stimulated echo in diffusion magnetic resonance imaging: introducing a π pulse for SNR enhancement

Cao

Zhang

Wang

et al. 2019

Magnetic Resonance in Med

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Purpose Anomalous diffusion in biological tissues can be examined by diffusion MRI for various applications, including tumor diagnosis and measurement of brain fiber pathways. However, the measurement of anomalous diffusion requires high b‐values for the diffusion gradient in MRI, and current MRI methods cannot provide a high SNR. This study aimed to improve on the standard stimulated echo (STE) to enhance the SNR in diffusion MRI with high b‐values. Methods Because of hardware limitations and human safety considerations, prolonging the diffusion time (Δ) is 1 of the few methods available to realize high b‐values. Here, we propose a new echo mechanism for diffusion MRI to enhance SNRs under long Δ. By introducing a π pulse at the midpoint between 2nd and 3rd π/2 pulses of STE, we refocus the magnetic moment vectors in the longitudinal plane before the third π/2 pulse is applied, which preserves the full echo signals. This sequence was compared with STE and spin echo (SE). Nine Δs were tested in a phantom. Multi b‐values with 2 Δs were tested in a mouse liver, brain, and tumor. Results Compared with STE and SE, the proposed improved STE (ISTE) exhibited an improved SNR in the phantom experiment and improved performance in the in vivo experiments. Conclusion By using the proposed echo mechanism in diffusion MRI, we enhanced the SNR of the images, which enables us to investigate diffusion behavior at higher b‐values and further facilitates the development of quantitative diffusion MRI and radiomics.

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“…Multishell diffusion imaging, however, allows to decompose the diffusion signal into related tissue compartments [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] (see [46] , [47] for reviews), and therefore offers additional specificity to white matter composition. Here we utilized multishell diffusion images of ADNI-3 advanced neuroimaging data set to decipher the origin of the increased white matter MD associated with the cognitive decline.…”

Section: Introductionmentioning

confidence: 99%

Nonparenchymal fluid is the source of increased mean diffusivity in preclinical Alzheimer's disease

Sepehrband

Cabeen

Barisano

et al. 2019

Alz & Dem Diag Ass & Dis Mo

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Introduction Although increased mean diffusivity of the white matter has been repeatedly linked to Alzheimer’s disease pathology, the underlying mechanism is not known. Methods Here, we used ADNI-3 multishell diffusion magnetic resonance imaging data to separate the diffusion signal of the parenchyma from less hindered fluid pools within the white matter such as perivascular space fluid and fluid-filled cavities. Results We found that the source of the pathological increase of the mean diffusivity is the increased nonparenchymal fluid, often found in lacunes and perivascular spaces. In this cohort, the cognitive decline was significantly associated with the fluid increase and not with the microstructural changes of the white matter parenchyma itself. The white matter fluid increase was dominantly observed in the sagittal stratum and anterior thalamic radiation. Discussion These findings are positive steps toward understanding the pathophysiology of white matter alteration and its role in the cognitive decline.

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A time‐efficient acquisition protocol for multipurpose diffusion‐weighted microstructural imaging at 7 Tesla

Cited by 18 publications

References 81 publications

Homologous laminar organization of the mouse and human subiculum

Homologous laminar organization of the mouse and human subiculum

Improved stimulated echo in diffusion magnetic resonance imaging: introducing a π pulse for SNR enhancement

Nonparenchymal fluid is the source of increased mean diffusivity in preclinical Alzheimer's disease

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