Validation of diffuse correlation spectroscopic measurement of cerebral blood flow using phase-encoded velocity mapping magnetic resonance imaging

Buckley, Erin M.; Hance, Dalton; Pawlowski, Thomas; Lynch, Jennifer M.; Wilson, Felice B.; Mesquita, Rickson C.; Durdurán, Turgut; Diaz, Laura K.; Putt, Mary; Licht, Daniel J.; Fogel, Mark A.; Yodh, Arjun G.

doi:10.1117/1.jbo.17.3.037007

Cited by 83 publications

(92 citation statements)

References 38 publications

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“…This observation agrees with our previous experience in healthy adults 20 and with several other publications that examined cerebrovascular reactivity to hypercapnia in patients with congenital heart defects using localized measurement techniques, such as DOS and DCS. 15,24,38 In addition to generating new physiologic data, this work also achieved several technical goals. First, it demonstrates the feasibility of a combined MRI-susceptometry and phase-contrast method to measure S v O 2 , CBF and CMRO 2, in neonates with complex CHD, all in absolute physiologic units.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have shown that changes of BFI relative to a baseline are strongly correlated with changes in CBF relative to baseline values measured by other CBF techniques. 15,21,24 Diffuse Optical Spectroscopy and Diffuse Correlation Spectroscopy Instrumentation and Study Protocol A schematic of the measurement protocol is provided in Figure 1, and further details are given in Appendix 1. First, baseline DOS measurements of absolute tissue physiologic parameters, i.e., HbR, HbO 2 , THC, and StO 2 were made on the patient's forehead while the subject was sedated, stabilized, and while vascular access was obtained outside the MRI scanner.…”

Section: Magnetic Resonance Imaging Measurementsmentioning

confidence: 99%

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Cerebral Oxygen Metabolism in Neonates with Congenital Heart Disease Quantified by MRI and Optics

Jain

Buckley

Licht

et al. 2013

J Cereb Blood Flow Metab

173

192

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Neonatal congenital heart disease (CHD) is associated with altered cerebral hemodynamics and increased risk of brain injury. Two novel noninvasive techniques, magnetic resonance imaging (MRI) and diffuse optical and correlation spectroscopies (diffuse optical spectroscopy (DOS), diffuse correlation spectroscopy (DCS)), were employed to quantify cerebral blood flow (CBF) and oxygen metabolism (CMRO 2 ) of 32 anesthetized CHD neonates at rest and during hypercapnia. Cerebral venous oxygen saturation (S v O 2 ) and CBF were measured simultaneously with MRI in the superior sagittal sinus, yielding global oxygen extraction fraction (OEF) and global CMRO 2 in physiologic units. In addition, microvascular tissue oxygenation (StO 2 ) and indices of microvascular CBF (BFI) and CMRO 2 (CMRO 2i ) in the frontal cortex were determined by DOS/DCS. Median resting-state MRI-measured OEF, CBF, and CMRO 2 were 0.38, 9.7 mL/minute per 100 g and 0.52 mL O 2 /minute per 100 g, respectively. These CBF and CMRO 2 values are lower than literature reports for healthy term neonates (which are sparse and quantified using different methods) and resemble values reported for premature infants. Keywords: cerebral blood flow; cerebral hemodynamics; diffuse optics; MRI; near-infrared spectroscopy; neonatal ischemia INTRODUCTION Congenital heart disease (CHD) affects B35,000 neonates each year in the United States. These patients suffer both short-and long-term neurologic sequelae. Periventricular leukomalacia is the most common cerebral injury found in this population. This type of injury is characterized by focal necrosis in the periventricular white matter, and it is associated with pyknotic glial nuclei and reactive gliosis. 1,2 During the early stages of brain development, the oligodendrocyte (brain glial cells) precursors are metabolically very active and highly susceptible to injury from reduced blood flow and oxygen delivery. Hence, hypoxiaischemia has been implicated as a major cause of this injury in CHD neonates.Periventricular leukomalacia leads to impaired myelination and has been linked to worse neurodevelopmental outcomes in premature infants and postulated to cause (at least in part) the impaired cognition and cerebral palsy commonly seen in this cohort of infants with CHD. 3,4 Quantification of the hemodynamic and metabolic state of these neonates via measurements of cerebral blood flow (CBF) and the cerebral metabolic rate of oxygen consumption (CMRO 2 ) should provide valuable information toward understanding the interaction between cardiac pathophysiology and subsequent cerebral health. Potentially, such new knowledge could help predict and prevent adverse outcomes.

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Section: Discussionmentioning

confidence: 99%

Section: Magnetic Resonance Imaging Measurementsmentioning

confidence: 99%

Cerebral Oxygen Metabolism in Neonates with Congenital Heart Disease Quantified by MRI and Optics

Jain

Buckley

Licht

et al. 2013

J Cereb Blood Flow Metab

173

192

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“…In fact, DCS CBF i correlates well with MR arterial spin labeling 38 and with phase-encoded velocity mapping (VENC) MRI measures of relative blood flow in the jugular veins and superior vena cava in neonates/children with congenital heart defect. 39 Further support for the use of DCS CBF i measures was provided by the high correlation (r 2 ¼ 0.73, Po0.01) between relative CBF i and Xenon CT cerebral blood perfusion measures in critically brain-injured adults. 40 These comparisons show that CBF i measured by DCS offers reasonable agreement with other modalities, in particular those providing perfusion measurements, and therefore provides a reliable index of CMRO 2 .…”

Section: Indices Of Cerebral Oxygen Metabolism and Cerebral Blood Flowmentioning

confidence: 99%

Cerebral Oxygen Metabolism in Neonatal Hypoxic Ischemic Encephalopathy during and after Therapeutic Hypothermia

Dehaes

Aggarwal

Lin

et al. 2013

J Cereb Blood Flow Metab

108

121

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Pathophysiologic mechanisms involved in neonatal hypoxic ischemic encephalopathy (HIE) are associated with complex changes of blood flow and metabolism. Therapeutic hypothermia (TH) is effective in reducing the extent of brain injury, but it remains uncertain how TH affects cerebral blood flow (CBF) and metabolism. Ten neonates undergoing TH for HIE and seventeen healthy controls were recruited from the NICU and the well baby nursery, respectively. A combination of frequency domain near infrared spectroscopy (FDNIRS) and diffuse correlation spectroscopy (DCS) systems was used to non-invasively measure cerebral hemodynamic and metabolic variables at the bedside. Results showed that cerebral oxygen metabolism (CMRO 2i ) and CBF indices (CBF i ) in neonates with HIE during TH were significantly lower than post-TH and age-matched control values. Also, cerebral blood volume (CBV) and hemoglobin oxygen saturation (SO 2 ) were significantly higher in neonates with HIE during TH compared with age-matched control neonates. Post-TH CBV was significantly decreased compared with values during TH whereas SO 2 remained unchanged after the therapy. Thus, FDNIRS-DCS can provide information complimentary to SO 2 and can assess individual cerebral metabolic responses to TH. Combined FDNIRS-DCS parameters improve the understanding of the underlying physiology and have the potential to serve as bedside biomarkers of treatment response and optimization. Keywords: cerebral blood circulation; cerebral hemoglobin oxygen saturation; cerebral metabolic rate of oxygen consumption; near infrared spectroscopy; neonatal hypoxic ischemic encephalopathy; therapeutic hypothermia INTRODUCTION Neonatal hypoxic ischemic encephalopathy (HIE) occurs in B2 to 3 per 1,000 live births in the USA, with devastating consequences including neurodevelopmental disabilities such as cerebral palsy, life-long cognitive impairment, and epilepsy.1 In HIE, there is a period of reduced blood flow (ischemia) and oxygen delivery (hypoxia) followed by reperfusion with transient energy recovery, and then a secondary energy failure.2 Treatment is aimed at preventing the cascade of events that begin with reperfusion and lead to secondary energy failure and inevitable cell death; this is the 'window of opportunity.' 3 Theories for injury mechanisms in this window suggest a central role for excitotoxicity and oxidative stress with the injury evolving over hours to weeks.2 Therapeutic hypothermia (TH) is the treatment of choice for HIE, as it is the only treatment with proven efficacy and acts through a variety of mechanisms, including those associated with decreased neuronal energy metabolism. 4 Although early studies showed that TH decreased rates of both mortality and disability, recently published long-term outcomes have demonstrated significance only for decreased mortality rates.5 In addition, a recent

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“…We then fit the diffusion correlation equation to the measured autocorrelation function, acquired sequentially, about once per second, to obtain the blood flow index (CBF i ) 10,11 . DCS measures of blood flow changes have been extensively validated 12,13 . By combining the FDNIRS measures of SO 2 with the DCS measures of CBF i , we achieve an estimate of cerebral oxygen metabolism (CMRO 2i ).…”

Section: Introductionmentioning

confidence: 99%

Non-invasive Optical Measurement of Cerebral Metabolism and Hemodynamics in Infants

Lin

Roche-Labarbe

Dehaes

et al. 2013

JoVE

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Perinatal brain injury remains a significant cause of infant mortality and morbidity, but there is not yet an effective bedside tool that can accurately screen for brain injury, monitor injury evolution, or assess response to therapy. The energy used by neurons is derived largely from tissue oxidative metabolism, and neural hyperactivity and cell death are reflected by corresponding changes in cerebral oxygen metabolism (CMRO 2 ). Thus, measures of CMRO 2 are reflective of neuronal viability and provide critical diagnostic information, making CMRO 2 an ideal target for bedside measurement of brain health.Brain-imaging techniques such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) yield measures of cerebral glucose and oxygen metabolism, but these techniques require the administration of radionucleotides, so they are used in only the most acute cases.Continuous-wave near-infrared spectroscopy (CWNIRS) provides non-invasive and non-ionizing radiation measures of hemoglobin oxygen saturation (SO 2 ) as a surrogate for cerebral oxygen consumption. However, SO 2 is less than ideal as a surrogate for cerebral oxygen metabolism as it is influenced by both oxygen delivery and consumption. Furthermore, measurements of SO 2 are not sensitive enough to detect brain injury hours after the insult 1,2 , because oxygen consumption and delivery reach equilibrium after acute transients 3 . We investigated the possibility of using more sophisticated NIRS optical methods to quantify cerebral oxygen metabolism at the bedside in healthy and brain-injured newborns. More specifically, we combined the frequency-domain NIRS (FDNIRS) measure of SO 2 with the diffuse correlation spectroscopy (DCS) measure of blood flow index (CBF i ) to yield an index of CMRO 2 (CMRO 2i ) 4,5 .With the combined FDNIRS/DCS system we are able to quantify cerebral metabolism and hemodynamics. This represents an improvement over CWNIRS for detecting brain health, brain development, and response to therapy in neonates. Moreover, this method adheres to all neonatal intensive care unit (NICU) policies on infection control and institutional policies on laser safety. Future work will seek to integrate the two instruments to reduce acquisition time at the bedside and to implement real-time feedback on data quality to reduce the rate of data rejection.

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Validation of diffuse correlation spectroscopic measurement of cerebral blood flow using phase-encoded velocity mapping magnetic resonance imaging

Cited by 83 publications

References 38 publications

Cerebral Oxygen Metabolism in Neonates with Congenital Heart Disease Quantified by MRI and Optics

Cerebral Oxygen Metabolism in Neonates with Congenital Heart Disease Quantified by MRI and Optics

Cerebral Oxygen Metabolism in Neonatal Hypoxic Ischemic Encephalopathy during and after Therapeutic Hypothermia

Non-invasive Optical Measurement of Cerebral Metabolism and Hemodynamics in Infants

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