Quantification of Regional Intrapulmonary Oxygen Partial Pressure Evolution during Apnea by 3He MRI
✍ Scribed by A.J. Deninger; B. Eberle; M. Ebert; T. Großmann; W. Heil; H.-U. Kauczor; L. Lauer; K. Markstaller; E. Otten; J. Schmiedeskamp; W. Schreiber; R. Surkau; M. Thelen; N. Weiler
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 172 KB
- Volume
- 141
- Category
- Article
- ISSN
- 1090-7807
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✦ Synopsis
We present a new method to determine in vivo the temporal evolution of intrapulmonary oxygen concentrations by functional lung imaging with hyperpolarized 3 Helium ( 3 He 3 ). Single-breath, single-bolus visualization of 3 He 3 administered to the airspaces is used to analyze nuclear spin relaxation caused by the local oxygen partial pressure p O2 (t). We model the dynamics of hyperpolarization in the lung by rate equations. Based hereupon, a double acquisition technique is presented to separate depolarization by RF pulses and oxygen induced relaxation. It permits the determination of p O2 with a high accuracy of up to 3% with simultaneous flip angle calibration using no additional input parameters. The time course of p O2 during short periods of breathholding is found to be linear in a pig as well as in a human volunteer. We also measured the wall relaxation time in the lung and deduced a lower limit of 4.3 min.