ABSTRACT
PURPOSE: To test the feasibility of regional fully quantitative ventilation measurement in free breathing derived by phase-resolved functional lung (PREFUL) MRI in the supine and prone positions. In addition, the influence of T2 * relaxation time on ventilation quantification is assessed. METHODS: Twelve healthy volunteers underwent functional MRI at 1.5 T using a 2D triple-echo spoiled gradient echo sequence allowing for quantitative measurement of T2 * relaxation time. Minute ventilation (ΔV) was quantified by conventional fractional ventilation (FV) and the newly introduced regional ventilation (VR), which corrects volume errors due to image registration. ΔVFV versus ΔVVR and ΔVVR versus ΔVVR with T2 * correction were compared using Bland-Altman plots and correlation analysis. The repeatability and physiological plausibility of all measurements were tested in the supine and prone positions. RESULTS: On global and regional scales a strong correlation was observed between ΔVFV versus ΔVVR and ΔVVR versus ΔVVRT2* (r > 0.93); however, regional Bland-Altman analysis showed systematic differences (p < 0.0001). Unlike ΔVVRT2* , ΔVVR and ΔVFV showed expected physiologic anterior-posterior gradients, which decreased in the supine but not in the prone position at second measurement during 3 min in the same position. For all quantification methods a moderate repeatability (coefficient of variation <20%) of ventilation was found. CONCLUSION: A fully quantified regional ventilation measurement using ΔVVR in free breathing is feasible and shows physiologically plausible results. In contrast to conventional ΔVFV, volume errors due to image registration are eliminated with the ΔVVR approach. However, correction for the T2 * effect remains challenging.
Subject(s)
Lung/physiology , Magnetic Resonance Imaging , Pulmonary Ventilation/physiology , Respiration , Adult , Female , Humans , Image Processing, Computer-Assisted , Lung/diagnostic imaging , Male , Middle Aged , Posture , Reproducibility of ResultsABSTRACT
A combined optical coherence tomography (OCT)-Raman probe was designed and built into a spectral domain OCT head, and its performance was evaluated and compared to the most common Raman probe setups, based on a fiber bundle and confocal free space optics. Due to the use of the full field of view of an OCT scanning lens, the combined probe has a superior performance within maximum permissible exposure limits, compared to the other two probes. Skin Raman spectra, recorded in vivo, further prove the feasibility of the OCT-Raman probe for the future in vivo clinical applications in skin cancer screening.
Subject(s)
Melanoma/diagnostic imaging , Skin Neoplasms/diagnostic imaging , Tomography, Optical Coherence , Early Detection of Cancer , Humans , Melanoma, Cutaneous MalignantABSTRACT
Enzymes in the cytochrome P450 1 family oxidize many common environmental toxicants. We identified a new CYP1, termed CYP1D1, in zebrafish. Phylogenetically, CYP1D1 is paralogous to CYP1A and the two share 45% amino acid identity and similar gene structure. In adult zebrafish, CYP1D1 is most highly expressed in liver and is relatively highly expressed in brain. CYP1D1 transcript levels were higher at 9h post-fertilization than at later developmental times. Treatment of zebrafish with potent aryl hydrocarbon receptor (AHR) agonists (3,3',4,4',5-pentachlorobiphenyl or 2,3,7,8-tetrachlorodibenzo-p-dioxin) did not induce CYP1D1 transcript expression. Morpholino oligonucleotide knockdown of AHR2, which mediates induction of other CYP1s, did not affect CYP1D1 expression. Zebrafish CYP1D1 heterologously expressed in yeast exhibited ethoxyresorufin- and methoxyresorufin-O-dealkylase activities. Antibodies against a CYP1D1 peptide specifically detected a single electrophoretically-resolved protein band in zebrafish liver microsomes, distinct from CYP1A. CYP1D1 in zebrafish is a CYP1A-like gene that could have metabolic functions targeting endogenous compounds.
