title: Boosting (19) F MRI-SNR efficient detection of paramagnetic contrast agents using ultrafast sequences.
abstract: (19) F MRI offers high specificity but usually low sensitivity. Here, paramagnetic relaxation enhancement is assessed as a method to improve SNR efficiency in (19) F MRI. Compounds with short relaxation times are used that combine fluorine and a paramagnetic ion within the same molecule. Different molecular designs provide T1 values in the range of 1.4-15 ms and T2*/T1 ratios from 0.3 to 1. Gradient echo, as well as ultrafast radial MR sequences, is optimized to achieve highest SNR efficiency. Compared to nonparamagnetic compounds, ultrafast sequences can yield a gain of up to a factor 27 in sensitivity, whereas the gain with gradient echo is only factor 11. Comparison among the paramagnetic compounds shows that T2*/T1 close to unity is a prerequisite for highest SNR efficiency gain and that best results are obtained for compounds with T1 in the range of 1-5 ms.
authors.affiliation: Department of Clinical Radiology, University Hospital Münster, Münster, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Schmid
authors.forename: Carsten
authors.initials: C
authors.lastname: Höltke
authors.forename: David
authors.initials: D
authors.lastname: Parker
authors.forename: Cornelius
authors.initials: C
authors.lastname: Faber
mesh_terms: D000465:Algorithms; D003287:Contrast Media; D005462:Fluorine Radioisotopes; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio
chemical_list: D003287:Contrast Media; D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals