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  • 1
    Keywords: -, BLOOD, blood flow, blood volume, BLOOD-FLOW, CONTRAST, CONTRAST-ENHANCED MRI, FLOW, Germany, HEAL
    Abstract: Purpose: Oxygen-enhanced magnetic resonance (MR)-ventilation imaging of the lung is based on the inhalation of a high concentration of oxygen (hyperoxia). However, the effect of hyperoxia on the pulmonary circulation is not yet fully understood. In this study the impact of hyperoxia on the pulmonary circulation was evaluated. Materials and Methods: Ten healthy volunteers were examined in a 1.5 T MRI system with contrast-enhanced perfusion MRI (saturation recovery 2D turboFLASH) of the lung and phase-contrast flow measurements in the pulmonary trunk. Both measurements were performed breathing room air (R-A) and, subsequently, 100% oxygen (15 L/mm) (O-2). Results: The perfusion measurements showed a significant difference between RA and 02 for the pulmonary blood flow (181 vs. 257 mL/min/100 mL, P = 0.04) and blood volume (14 vs. 21 mL/100 mL, P = 0.008). The mean transit time of the contrast bolus was not changed (P = 0.4) in the dorsal part of the lung, whereas it was significantly prolonged (P = 0.006) in the central part. The mean heart rate during flow measurements breathing RA (67 +/- 11 beats/min) and O-2 (61 +/- 12 beats/min) were not significantly different (P = 0.055). The average cardiac output (pulmonary trunk) was not significantly lower while breathing O-2 (R-A: 5.9 vs. O-2: 5.5 L/min, P = 0.054). Conclusion: Hyperoxia causes a significant increase and redistribution of the pulmonary perfusion, whereas it leads to a not significant decrease in cardiac output. Thus, for MR-perfusion and MR-flow measurements oxygen inhalation should be avoided, if possible. In the context of oxygen-enhanced MR-ventilation imaging of the lung the contribution of this effect needs to be further evaluated
    Type of Publication: Journal article published
    PubMed ID: 17414523
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  • 2
    Keywords: LUNG ; VENTILATION ; MRI ; SEQUENCE ; MR pulse sequence ; DIFFUSING-CAPACITY ; Inversion recovery ; PRELIMINARY CLINICAL-EXPERIENCE
    Abstract: The purpose of this study was to evaluate in vivo the influence of inversion pulse slice selectivity on oxygen-enhanced magnetic resonance imaging (MRI). Thirteen healthy volunteers were studied with a two-dimensional cardiac- and respiratory-gated adiabatic inversion-recovery half-Fourier single-shot turbo spin-echo (HASTE) sequence with either slice-selective or non-slice-selective inversion recovery (IR) pulse at inversion times increasing from 300 to 1400 ms. The signal-to-noise ratio (SNR) at every inversion time (TI), real signal difference (Delta SI), and relative enhancement ratio of lung parenchyma at TI a parts per thousand yen 800 ms were statistically compared for oxygen-enhanced and non-oxygen-enhanced MR images with slice-selective or non-slice-selective IR pulses. The SNRs of acquisitions with slice-selective IR pulses were significantly higher than those of non-sliceselective IR pulses (P 〈 0.05). At TI 800 ms, the Delta SI of lung parenchyma on IR-HASTE images with slice-selective inversion pulse type was significantly higher than on that with the non-slice-selective type (P 〈 0.05). Relative enhancement ratios of the slice-selective IR pulses were significantly lower than those of non-slice-selective IR pulses at TIs between 800 and 1400 ms (P 〈 0.05). Slice selectivity of inversion pulse type affects oxygen-enhanced MRI in vivo
    Type of Publication: Journal article published
    PubMed ID: 21607837
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  • 3
    Keywords: IN-VIVO ; LUNG ; VIVO ; IMAGES ; imaging ; VENTILATION ; NUCLEAR-MEDICINE ; TIME ; MR ; MRI ; SEQUENCE ; SIGNAL ; NO ; DIFFERENCE ; nuclear medicine ; OXYGEN ; radiology ; INHALATION ; HEALTHY-VOLUNTEERS ; ENHANCEMENT ; methods ; NUCLEAR ; USA ; in vivo ; phantom ; DIFFUSING-CAPACITY ; block ; TURBO SPIN-ECHO ; inversion-recovery ; fast imaging ; pulse sequence
    Abstract: Purpose: To demonstrate the influence of inversion pulse type and invesion time for assessment of oxygen-enhancement on centrically-reordered, non-slice-selective inversion-recovery (IR) half-Fourier single-shot turbo spin-echo (HASTE) sequence. Materials and Methods: Phantoms with and without 100% oxygen and there healthy volunteers were studied with two-dimensional (2D) centrically-reordered non-slice selective IR-HASTE sequence with either composite or block inversion-recovery pulse at increasing inversion times from 200 to 1800 msec. Signal-to-noise ratios (SNRs) of phatom, real signal differences, and relative enhanced and non-oxygen-enhanced MR images on composite and block pulse type were statistically compared at each TI. Results: SNRs at Tis of 200 and 400 msec using the composite inversion pulse type were significantly lower than those with the block inversion pulse in the in vivo study (P 〈 0.05), although no significantly differences were observed in the phantom study and in the in vivo study at inversion times greater than or equal to 600 msec. Real signal intensity (SI) differences at 400 and 600 msec of the composite inversion pulse type were significantly higher than those with the block inversion pulse type (P 〈 0.05). Relative enhancement ratio at 800 msec with the composite inversion pulse were significantly lower than that with the block inversion pulse (P 〈 0.05)
    Type of Publication: Journal article published
    PubMed ID: 17896357
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