“The Pituitary within GRASP” – Golden-Angle Radial Sparse Parallel Dynamic MRI Technique and Applications to the Pituitary Gland

Lee, Matthew; Young, Matthew; Fatterpekar, Girish M.

doi:10.1053/j.sult.2021.04.007

Cited by 4 publications

(13 citation statements)

References 27 publications

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“…4,18 GRASP imaging offers several advantages over conventional DCE-MRI techniques, both generally and specifically for brain tumor imaging. 11 GRASP's continuous radial sampling and reconstruction process provides high isotropic spatial resolution over the entire brain and adjustable temporal resolution, whereas conventional DCE-MRI techniques often limit the field of view or image resolution to accommodate multiple separate acquisitions. Unlike conventional DCE-MRI, GRASP is robust against artifacts from respiratory motion and arterial pulsation while also providing homogeneous fat suppression, which can aid the differentiation of fat, hemorrhage, and surgical packing in the postoperative setting.…”

Section: Discussionmentioning

confidence: 99%

Distinguishing Brain Metastasis Progression From Radiation Effects After Stereotactic Radiosurgery Using Longitudinal GRASP Dynamic Contrast-Enhanced MRI

et al. 2022

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BACKGROUND:Differentiating brain metastasis progression from radiation effects or radiation necrosis (RN) remains challenging. Golden-angle radial sparse parallel (GRASP) dynamic contrast-enhanced MRI provides high spatial and temporal resolution to analyze tissue enhancement, which may differ between tumor progression (TP) and RN.OBJECTIVE:To investigate the utility of longitudinal GRASP MRI in distinguishing TP from RN after gamma knife stereotactic radiosurgery (SRS).METHODS:We retrospectively evaluated 48 patients with brain metastasis managed with SRS at our institution from 2013 to 2020 who had GRASP MRI before and at least once after SRS. TP (n = 16) was pathologically confirmed. RN (n = 16) was diagnosed on either resected tissue without evidence of tumor or on lesion resolution on follow-up. As a reference, we included a separate group of patients with non–small-cell lung cancer that showed favorable response with tumor control and without RN on subsequent imaging (n = 16). Mean contrast washin and washout slopes normalized to the superior sagittal sinus were compared between groups. Receiver operating characteristic analysis was performed to determine diagnostic performance.RESULTS:After SRS, progression showed a significantly steeper washin slope than RN on all 3 follow-up scans (scan 1: 0.29 ± 0.16 vs 0.18 ± 0.08, P = .021; scan 2: 0.35 ± 0.19 vs 0.18 ± 0.09, P = .004; scan 3: 0.32 ± 0.12 vs 0.17 ± 0.07, P = .002). No significant differences were found in the post-SRS washout slope. Post-SRS washin slope differentiated progression and RN with an area under the curve (AUC) of 0.74, a sensitivity of 75%, and a specificity of 69% on scan 1; an AUC of 0.85, a sensitivity of 92%, and a specificity of 69% on scan 2; and an AUC of 0.87, a sensitivity of 63%, and a specificity of 100% on scan 3.CONCLUSION:Longitudinal GRASP MRI may help to differentiate metastasis progression from RN.

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Section: Discussionmentioning

confidence: 99%

Distinguishing Brain Metastasis Progression From Radiation Effects After Stereotactic Radiosurgery Using Longitudinal GRASP Dynamic Contrast-Enhanced MRI

et al. 2022

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“…Recent studies have proven the importance of this technique via the detection of microadenomas in patients, particularly those with Cushing's disease, with a sensitivity of 67-95% compared with that of 50-60% under conventional contrast-enhanced MRI [30][31][32]. Microadenomas show delayed enhancement and regression, making them more visible on DCE-MRI than conventional sequences, and a few may only appear on dynamic sequences [33]. Dynamic contrast-enhanced magnetic resonance imaging has become routine for initial imaging studies in central endocrine disorders, namely, prolactinomas, due to its negative predictive value and high sensitivity in detecting microadenomas [33].…”

Section: Dynamic Contrast-enhanced Magnetic Resonance Imagingmentioning

confidence: 99%

“…Microadenomas show delayed enhancement and regression, making them more visible on DCE-MRI than conventional sequences, and a few may only appear on dynamic sequences [33]. Dynamic contrast-enhanced magnetic resonance imaging has become routine for initial imaging studies in central endocrine disorders, namely, prolactinomas, due to its negative predictive value and high sensitivity in detecting microadenomas [33]. Additionally, DCE-MRI advances surgical planning by distinguishing between normal tissue and lesions [8,34].…”

Section: Dynamic Contrast-enhanced Magnetic Resonance Imagingmentioning

confidence: 99%

“…In most instances, the lack of temporal resolution hinders quantitative pharmacokinetic analysis. In the postoperative setting, conventional techniques are insufficient in fat saturation, which typically is advantageous in contrasts of hemorrhage, fat, and surgical packing material [33].…”

Section: Dynamic Contrast-enhanced Magnetic Resonance Imagingmentioning

confidence: 99%

“…Golden-angle radial sparse parallel imaging develops all the dynamic data by completion in a single persistent scan. First, the data is separated into sequential time frames and then recreated via an iterative method, which connects compressed sensing and parallel imaging [33,36,37].…”

Section: Golden-angle Radial Sparse Parallel Imagingmentioning

confidence: 99%

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New Progress in Imaging of Pituitary Diseases

Wu¹

2024

Frontiers in Neuroimaging

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In the last 20 years, there have been advances in imaging techniques for pituitary diseases. Magnetic resonance imaging (MRI) particularly presents high-quality structural images and the essential information needed to authorize surgery, radiation therapy, and/or drug therapy. These images can assist in monitoring long-term outcomes. Recent technological advances, such as the advent of 7-Tesla MRI, have been used for measuring tumor consistency in pituitary adenomas. Microadenomas and other pituitary incidentaloma have been more recognized in the presence of golden-angle radial sparse parallel imaging and conventional dynamic contrast-enhanced techniques. However, standard structural (anatomical) imaging, mainly in the form of MRI, acts inadequately to identify all tumors, especially microadenomas (< 1 cm diameter), recurrent adenomas, and several incidentalomas. In this respect, nuclear isotope (radionuclide) imaging promotes tumor detection beneficially. All these imaging improvements may play a central role in clinical practice, especially when considering diagnosis, differential diagnosis, or definitive intervention. They further form accurate diagnosis, advise surgery, and decrease the risk of disrupting normal pituitary function.

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Understanding Permeability Changes in Vestibular Schwannomas as Part of the Dynamic Response to Radiosurgery Using Golden-Angle Radial Sparse Parallel Imaging: A Retrospective Study

Meng,

Lee,

Berger

et al. 2024

Neurosurgery

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BACKGROUND AND OBJECTIVES: Vestibular schwannomas demonstrate different responses after stereotactic radiosurgery (SRS), commonly including a transient loss of internal enhancement on postcontrast T1-weighted MRI thought to be due to an early reduction in tumor vascularity. We used dynamic contrast-enhanced based golden-angle radial sparse parallel (GRASP) MRI to characterize the vascular permeability changes underlying this phenomenon, with correlations to long-term tumor regression. METHODS: Consecutive patients with vestibular schwannoma who underwent SRS between 2017 and 2019, had a transient loss of enhancement after SRS, and had long-term longitudinal GRASP studies (6, 18, and 30 months) were included in this retrospective cohort analysis (n = 19). Using GRAVIS (https://gravis-imaging.org/gravis/), an analysis pipeline for GRASP studies, we extracted the key parameters normalized to the venous sinus from a region of interest within the tumor. RESULTS: The peak, area under the curve (AUC), and wash-in phase slope were significantly reduced at 6, 18, and 30 months after SRS (corrected P < .05), even while the internal enhancement returned in the tumors. Larger pre-SRS tumors were more likely to have a greater reduction in peak (P = .013) and AUC (P = .029) at 6 months. In a subset of patients (N = 13) with long-term follow-up, the median percentage reduction in tumor volume was 58% at a median of 62 months. These patients showed a strong correlation between peak, AUC, and wash-in phase slope changes at 6 months and tumor volume at the last follow-up. CONCLUSION: After SRS and loss of internal contrast uptake within vestibular schwannomas, a slow vascular permeability dynamic persisted, suggesting the presence of postradiation processes such as fibrosis. We show for the first time, using GRASP, a quantitative assessment of the vascular radiobiological effect.

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“The Pituitary within GRASP” – Golden-Angle Radial Sparse Parallel Dynamic MRI Technique and Applications to the Pituitary Gland

Cited by 4 publications

References 27 publications

Distinguishing Brain Metastasis Progression From Radiation Effects After Stereotactic Radiosurgery Using Longitudinal GRASP Dynamic Contrast-Enhanced MRI

Distinguishing Brain Metastasis Progression From Radiation Effects After Stereotactic Radiosurgery Using Longitudinal GRASP Dynamic Contrast-Enhanced MRI

New Progress in Imaging of Pituitary Diseases

Understanding Permeability Changes in Vestibular Schwannomas as Part of the Dynamic Response to Radiosurgery Using Golden-Angle Radial Sparse Parallel Imaging: A Retrospective Study

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