Dataset Information

Quantification of whole-brain oxygenation extraction fraction and cerebral metabolic rate of oxygen consumption in adults with sickle cell anemia using individual T₂ -based oxygenation calibrations.

ABSTRACT:

Purpose

To evaluate different T₂ -oxygenation calibrations for estimating venous oxygenation in people with sickle cell anemia (SCA).

Methods

Blood T₂ values were measured at 3 T in the internal jugular veins of 12 healthy volunteers and 11 SCA participants with no history of stroke, recent transfusion, or renal impairment. T₂ -oxygenation relationships of both sickled and normal blood samples were calibrated individually and compared with values generated from published models. After converting venous T₂ values to venous oxygenation, whole-brain oxygen extraction fraction and cerebral metabolic rate of oxygen were calculated.

Results

Sickle blood samples' oxygenation values calculated from our individual calibrations agreed well with measurements using a blood analyzer, whereas previous T₂ calibrations based on normal blood samples showed 13%-19% underestimation. Meanwhile, oxygenation values calculated from previous grouped T₂ calibration for sickle blood agreed well with experimental measurement on averaged values, but showed up to 20% variation for several individual samples. Using individual T₂ calibrations, the whole-brain oxygen extraction fraction and cerebral metabolic rate of oxygen of SCA participants were 0.38 ± 0.08 and 172 ± 42 µmol/min/100 g, respectively, which were comparable to those values measured on healthy volunteers.

Conclusion

Our results confirm that sickle blood T₂ values not only depend on the hematocrit and oxygenation values, but also on other hematological factors. The individual T₂ calibrations minimized the effect of heterogeneity of sickle blood between different SCA populations and improved the accuracy of T₂ -based oximetry. The measured oxygen extraction fraction and cerebral metabolic rate of oxygen of this group of SCA participants were found to not differ significantly from those of healthy individuals.

SUBMITTER: Li W

PROVIDER: S-EPMC6879787 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

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Publications

Quantification of whole-brain oxygenation extraction fraction and cerebral metabolic rate of oxygen consumption in adults with sickle cell anemia using individual T<sub>2</sub> -based oxygenation calibrations.

Li Wenbo W Xu Xiang X Liu Peiying P Strouse John J JJ Casella James F JF Lu Hanzhang H van Zijl Peter C M PCM Qin Qin Q

Magnetic resonance in medicine 20190904 3

<h4>Purpose</h4>To evaluate different T<sub>2</sub> -oxygenation calibrations for estimating venous oxygenation in people with sickle cell anemia (SCA).<h4>Methods</h4>Blood T<sub>2</sub> values were measured at 3 T in the internal jugular veins of 12 healthy volunteers and 11 SCA participants with no history of stroke, recent transfusion, or renal impairment. T<sub>2</sub> -oxygenation relationships of both sickled and normal blood samples were calibrated individually and compared with values g ...[more]

PMID: 31483528

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Project description:Research in sickle cell anemia (SCA) has used, with limited race-matched control data, binary categorization of patients according to the presence or absence of silent cerebral infarction (SCI). SCI have primarily been identified using low-resolution MRI, with radiological definitions varying in lesion length and the requirement for abnormality on both fluid attenuated inversion recovery (FLAIR) and T1-weighted images. We aimed to assess the effect of published SCI definitions on global, regional, and lobar lesion metrics and their value in predicting cognition. One hundred and six patients with SCA and 48 controls aged 8–30 years underwent 3T MRI with a high-resolution FLAIR sequence and Wechsler cognitive assessment. Prevalence, number, and volume of lesions were calculated using a semi-automated pipeline for SCI defined as: (1) Liberal: any length (L-SCI); (2) Traditional: >3 mm in greatest dimension (T-SCI); (3) Restrictive; >3 mm in greatest dimension with a corresponding T1-weighted hypo-intensity (R-SCI). Globally, as hypothesized, there were large effects of SCI definition on lesion metrics in patients and controls, with prevalence varying from 24–42% in patients, and 4–23% in controls. However, contrary to hypotheses, there was no effect of any global metric on cognition. Regionally, there was a consistent distribution of SCI in frontal and parietal deep and juxta-cortical regions across definitions and metrics in patients, but no consistent distribution in controls. Effects of regional SCI metrics on cognitive performance were of small magnitude; some were paradoxical. These findings expose the challenges associated with the widespread use of SCI presence as a biomarker of white-matter injury and cognitive dysfunction in cross-sectional high-resolution MRI studies in patients with SCA. The findings indicate that with high-resolution MRI: (1) radiological definitions have a large effect on resulting lesion groups, numbers, and volumes; (2) there is a non-negligible prevalence of lesions in young healthy controls; and (3) at the group-level, there is no cross-sectional association between global lesion metrics and general cognitive impairment irrespective of lesion definition and metric. With high-resolution multi-modal MRI, the dichotomy of presence or absence of SCI does not appear to be a sensitive biomarker for the detection of functionally significant pathology; the search for appropriate endpoints for clinical treatment trials should continue.

Dataset Information

Quantification of whole-brain oxygenation extraction fraction and cerebral metabolic rate of oxygen consumption in adults with sickle cell anemia using individual T₂ -based oxygenation calibrations.

Purpose

Methods

Results

Conclusion

Publications

Quantification of whole-brain oxygenation extraction fraction and cerebral metabolic rate of oxygen consumption in adults with sickle cell anemia using individual T<sub>2</sub> -based oxygenation calibrations.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Quantification of whole-brain oxygenation extraction fraction and cerebral metabolic rate of oxygen consumption in adults with sickle cell anemia using individual T2 -based oxygenation calibrations.

Purpose

Methods

Results

Conclusion

Publications

Quantification of whole-brain oxygenation extraction fraction and cerebral metabolic rate of oxygen consumption in adults with sickle cell anemia using individual T<sub>2</sub> -based oxygenation calibrations.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Quantification of whole-brain oxygenation extraction fraction and cerebral metabolic rate of oxygen consumption in adults with sickle cell anemia using individual T₂ -based oxygenation calibrations.